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Percutaneous Mitral Valve Repair for Chronic Ischemic Mitral Regurgitation: A Real-Time Three-Dimensional Echocardiographic Study in an Ovine Model
Abstract
Although surgical annuloplasty is the standard repair for ischemic mitral regurgitation (IMR), its application is limited by high morbidity and mortality. Using 2D and real-time 3D echocardiography in an ovine model of chronic IMR, we evaluated the geometric impact and short-term efficacy of a percutaneous transvenous catheter-based approach for mitral valve (MV) repair using a novel annuloplasty device placed in the coronary sinus.
Six sheep developed IMR 8 weeks after induced posterior myocardial infarction. An annuloplasty device optimized to reduce anterior-posterior (A-P) mitral annular dimension and MR was placed percutaneously in the coronary sinus. Mitral annular A-P and commissure-commissure dimensions and MV tenting area (MVTa) in 3 parallel A-P planes (medial, central, and lateral) were assessed by real-time 3D echocardiography with 3D software. The annuloplasty device reduced MR jet area from 5.4+/-2.6 to 1.3+/-0.9 cm2 (P<0.01), mitral annular A-P dimension in both systole and diastole (24.3+/-2.5 to 19.7+/-2.4 mm; P<0.03; 31.0+/-3.9 to 24.7+/-2.1 mm; P<0.001), and MVTa at mid systole in all 3 planes (153+/-46 to 93+/-24 mm2, P<0.01; 140+/-47 to 88+/-23 mm2, P<0.03; and 103+/-23 to 87+/-26 mm2, P<0.03).
Percutaneous coronary sinus-based mitral annuloplasty reduces chronic IMR by reducing mitral annular A-P diameter and MVTa. This suggests the potential clinical application of a new nonsurgical therapeutic approach in patients with IMR.
... This is because the native valve still functions as a valve after the procedure. Previous animal studies have reported the low reproducibility of animal MR models [6][7][8], limiting the assessment of performance, efficacy and safety of MVr devices. The international standard for cardiac valve repair devices, ISO 5910, outlines in vitro, preclinical in vivo and clinical evaluations. ...
... If MR models can be successfully produced in in vivo animal models, they may be the best for preclinical studies. However, previous studies have indicated difficulty in producing in vivo models of MR [6][7][8][21][22][23][24][25]. Although Hill et al. [21] had successfully produced severe DMR in all 12 sheep by cutting the P2 chordae under direct vision, none of them could be weaned off the cardiopulmonary bypass and required immediate MR correction. ...
... The development of in vivo FMR models tended to be more difficult. In most studies, iatrogenic myocardial ischaemia models have been made to produce FMR [6,7,24,25]. Unlike DMR models, FMR developed $7-8 weeks after the procedure. ...
OBJECTIVES
Transcatheter mitral valve repair is an emerging alternative to the surgical repair. This technology requires preclinical studies to assess efficacy in mitigating mitral regurgitation. However, ex vivo mitral regurgitation models are not established. We developed two novel repairable models, functional and degenerative, which can quantitatively assess regurgitation and effect of intervention.
METHODS
We used porcine mitral valves and a pulsatile flow circulation system. In the functional mitral regurgitation model, the annulus was immersed in 0.1% collagenase solution and dilated using 3D-printed dilators. To control the regurgitation grade, the sizes of the dilator and silicone sheet in which the valve was sutured to were adjusted. Chordae of P2 were severed in the degenerative model, and the number of severed chordae was adjusted to control the regurgitation grade. Models were repaired using the edge-to-edge or artificial chordae technique.
RESULTS
Mean regurgitant fraction of the moderate–severe functional and degenerative models were 47.9% (SD: 2.2%) and 58.5% (SD: 8.0%), which were significantly reduced to 28.7% (SD: 4.4%) (p < 0.001) and 26.0% (SD: 4.4%) (p < 0.001) after the valve repair procedures. Severe functional model had a mean regurgitant fraction of 59.4% (SD: 6.0%).
CONCLUSIONS
Both functional and degenerative models could produce sufficient mitral regurgitation levels that meet the interventional indication criteria. The repairable models are valuable in evaluating the efficacy of valve repair procedures and devices. The ability to control amount of regurgitation enhances the versatility and reliability of these models. These reproducible models could expedite the development of novel devices.
... La proximité anatomique Étude de la relation entre l'anneau mitral et la circulation coronaire dans l'insuffisance mitrale par scanner cardiaque K Warin-Fresse et al. du SC et de l'AM permet de réduire le diamètre de l'AM au cours de son demicerclage entrainant ainsi une meilleure coaptation des feuillets mitraux. La faisabilité de cette technique a été testée et validée sur des modèles animaux (5)(6)(7)(8). Elle est encore en cours d'évaluation chez l'homme et des résultats préliminaires ont été décrits (9). Cette technique améliorerait la survie, réduirait le risque d'endocardite, des complications thromboemboliques et préserverait mieux la fonction ventriculaire gauche (10)(11)(12)(13)(14)(15)(16). ...
... Lors de cette mise en tension de l'anneau, s'il existe une artère coronaire entre le SC et la paroi atriale (surcroisement), l'écrasement de l'artère coronaire pourrait entraîner son occlusion, source potentielle d'ischémie myocardique. Des études réalisées chez l'animal (5)(6)(7)(8) (23). Avec l'augmentation du nombre de détecteurs des scanners MB, la résolution spatiale augmente et permet une analyse de plus en plus fine des rapports SC-artères coronaires (24). ...
PurposeTo evaluate anatomical relationships between mitral annulus (MA), coronary arteries and coronary sinus (CS) in two groups of patients with and without moderate mitral insufficiency on coronary CTA to identify candidates to percutaneous mitral valve annuloplasty via the coronary sinus without risk of coronary artery occlusion.
... Assim como no caso das próteses de valva aórtica, o modelo ovino é o preferido para avaliação in vivo de dispositivos percutâneos de valva mitral. Até hoje, foram publicados os dados de dois tipos de modelos animais [76][77][78][79] . Um deles é o modelo de insuficiência cardíaca induzida por estimulação rápida, e o outro é o modelo de insuficiência mitral (IM) isquêmica. ...
... Talvez não seja necessário um modelo "doente" para o desenvolvimento de dispositivos ou para a elaboração de testes de durabilidade dos protocolos de colocação ideal. Duas abordagens percutâneas -reparo borda a borda e anuloplastia -foram submetidas a extensos estudos pré-clínicos e a uma análise clínica preliminar, como mostra a tabela: 2) Anuloplastia: foram desenvolvidas diversas técnicas percutâneas para alterar a geometria do anel mitral, como anuloplastia baseada no seio coronário, anuloplastia intracavitária direta e outros dispositivos constritivos novos [76][77][78][79]85 . O encurtamento ou remodelamento do anel por meio da inserção de um dispositivo no seio coronário pode imitar uma anuloplastia cirúrgica. ...
The treatment of cardiovascular disease has changed dramatically over the past 2 decades, allowing patients to live longer and better quality lives. The introduction of new therapies has contributed much to this success. Nowhere has this been more evident than in interventional cardiology, where percutaneous cardiovascular intervention has evolved in the past 2 decades from a quirky experimental procedure to a therapeutic cornerstone for patients with symptomatic cardiovascular disease. The development of these technologies from the earliest stages requires preclinical experiments using animal models. Once introduced into the clinical arena, an understanding of therapeutic mechanisms of these devices can be ascertained through comparisons of animal model research findings with clinical pathological specimens. This review provides an overview of the emerging role, results of preclinical studies and development, and evaluation of animal models for percutaneous cardiovascular intervention technologies for patients with symptomatic cardiovascular disease.
... It has been reported that extracted 3D images obtained by multiplane transesophageal echocardiography could be used in the evaluation of non-planarity and area change of the mitral annulus in patients with an annuloplasty ring3839. Real-time 3D methods were also feasible in the evaluation of non-planarity and area change of the mitral annulus in animals and in patients404142434445. Saddle-shaped geometry of the mitral annulus is clearly visualized by 3D echocardiography . ...
... tion, such detailed geometric evaluation should be performed in order to improve surgical results in patients with ischemic mitral regurgitation.Figure 6 shows mitral annulus and valve morphology extracted from multiple annular points and curved leaflets' lines4445. A non-surgical approach to manage ischemic mitral regurgitation was introduced recently, and realtime 3D echo was used to evaluate geometric changes of the mitral annulus before and after percutaneous mitral valve repair [43]. ...
Three-dimensional (3D) echocardiography is one of the most promising methods for the diagnosis of cardiac disease. Left and right ventricular size and function are currently evaluated with 2D echocardiography. However, for unpredictable asymmetry of the chamber geometry, conventional 2D echocardiography cannot be used to accurately determine absolute chamber volumes and ejection fraction. As for valvular heart diseases, the 3D echo approach has proven to be the most unique, powerful, and convincing method for understanding the complicated anatomy of the valves and their dynamism. The method has been useful for surgical management, including robotic mitral valve repair. Moreover, this method has become indispensable for nonsurgical procedures such as edge-to-edge mitral valve repair. Color Doppler 3D echo has also been valuable to identify the location of the regurgitant orifice, and the severity and character of the valvular regurgitation. In addition, 3D echo is invaluable in the diagnosis and management of congenital heart disease and in certain other situations, such as evaluation of the aortic annulus for transcatheter aortic valve implantation or replacement. It is now clear that 3D echocardiography, especially with the continued development of real-time 3D transesophageal echo technology, will enhance the diagnosis and management of patients with heart diseases.
... Beneficial effects of transcatheter MV annuloplasty on MR have been reported. 20) The present study may suggest further beneficial influences of transcatheter annuloplasty on the MV annulus and PMs' dynamic instabilities. ...
The mechanism of systolic annular expansion in mitral valve prolapse (MVP) is not clarified. Since annular expansion is systolic outward shift of MV leaflet/chorda tissue complex at superior and outer ends, annular expansion could be related to inward (superior) shift of the complex at another inferior and inner end of the papillary muscle (PM) tip and/or systolic lengthening of the tissue complex, especially MV leaflets.
MV annulus systolic expansion, PMs' systolic superior shift, and MV leaflets' systolic lengthening were evaluated by echocardiography with a speckle tracking analysis in 25 normal subjects, 25 subjects with holo-systolic MVP and 20 subjects with late-systolic MVP.
PMs' superior shift, MV leaflets' lengthening, MV annular area at the onset of systole and subsequent MV annulus expansion were significantly greater in late-systolic MVP than in holo-systolic MVP (4.6 ± 1.6 versus 1.5 ± 0.7 mm/m², 2.5 ± 1.4 versus 0.6 ± 2.0 mm/m², 6.8 ± 2.5 versus 5.7 ± 1.0 cm²/m² and 1.6 ± 0.8 versus 0.1 ± 0.5 cm²/m², P < 0.001, respectively). Multivariate analysis identified MV leaflets' lengthening and PMs' superior shift as independent factors associated with MV annular expansion.
Conclusions: These results suggest that systolic MV annular expansion in MVP is related to abnormal MV leaflets' lengthening and PMs' superior shift.
... While isolated mitral valve surgery has not demonstrated a benefit in this scenario, new evidences have shown a benefit to transcatheter intervention in patients with secondary MR and LVEF ≥ 20%, who remained symptomatic in spite of optimized clinical treatment, provided that the procedure is not indicated in more advanced phases of the natural history of VHD. [67][68][69][70][71][72] For more appropriate indication and more thorough approach, cases of secondary MI should be discussed with the Heart Team before the decision is made ( Figure 4). ...
... In this study, the mechanical and structural properties of five types of aged human and ovine chordae tendinae were characterized and compared. Our mechanical testing data for aged human and ovine chords are consistent with published data on human [48] and porcine chords [49][50][51][52]. ...
Objective: Mitral regurgitation and prolapse are the two most common diseases of the mitral valve and result in the leakage of blood back into the left atrium during systole. Rupture of the chordae tendinae is the most common cause of mitral insufficiency. The goal of this study was to characterize the biomechanical properties of the mitral valve chordae tendineae of aged human and ovine hearts. Materials and Methods: A total of 115 chordae specimens from fresh ovine hearts (n=18, weight = 374.833 47.947g, age of 1-2 year old), and 152 from human hearts (n=14, weight = 516.538 125.718g, mean age of 76.29 10.35 years old) were subjected to uniaxial tensile tests using marker tracking technology. The elastic and failure properties of five types of chordae tendineae were characterized, namely the anterior strut, anterior marginal, anterior basal, posterior marginal, and posterior basal chordae. The elastic properties were fitted with the nonlinear hyperelastic Ogden material model. The microstructure of the chordae samples was assessed through histology. Results: Human anterior basal and strut chords were significantly larger than the corresponding ovine chords. The mechanical properties of human chords were all similar while there were variations in the mechanical properties among ovine chords of differing type. The human chords were significantly stiffer and less extensible, yet stronger, than the corresponding ovine chords. These findings can be explained by histology results: collagen fibers in the human chords were nearly straight which resulted in reduced extensibility, while the collagen fibers in the ovine chords were highly crimped which resulted in high extensibility. Conclusions: Aged human and ovine chordae tendinae have significantly different structure and material properties.
... Moreover, for prosthetic valve device approval, the Food and Drug Administration (FDA) mandates pre-clinical animal trials, using either porcine or ovine models, to demonstrate sufficient safety including performance and handling, as well as to study the efficacy of new valve devices [237]. While many disparate results between human and animal trials have been observed, the current assumption taken for heart valve device trials (such as for transcatheter valve intervention [137,138,[238][239][240][241])porcine and ovine animal models are similar to those of aged humans -is still prevailing. ...
Surgical treatment for severe functional MR often involves mitral annuloplasty to improve leaflet apposition and ultimately downsize the dilated mitral valve. However, the high rate of operative mortalities of up to 6 ~12% have limited the more expanded use of this procedure. Recently, minimally invasive percutaneous transvenous mitral annuloplasty (PTMA) approaches using entirely catheter-based methods have been developed to reduce procedural morbidity and mortality. One of the approaches is to utilize the proximal location of the coronary sinus (CS) to the mitral annulus (MA) to percutaneously deploy a PTMA device within CS vessel. When the device contracts, it indirectly reshapes the MA and decreases MR. Although the approach has been shown to be promising in several animal studies, device dysfunction and fatigue fracture have been reported in human clinical trials. In this research, integrated experimental and computational studies were performed to apply quantitative analysis to study the biomechanical tissue-stent interaction (TSI) between PTMA device and CS vessel. Both human and animal CS tissue properties were characterized experimentally and implemented into finite element (FE) simulation. Realistic patient-specific geometries of the CS vessel were obtained from clinical imaging data and reconstructed into three-dimensional (3D) FE model. By incorporating proper tissue material properties and realistic 3D patient-specific geometries, FE simulation of the device deployment into the vessel could be achieved to investigate TSI and the associated biomechanics involved in the system. Quantitative understanding of the biomechanics in PTMA intervention is clearly an enabling step for science-based design of the devices.
... A percutaneous mitral annuloplasty device (CARILLON) has been designed to be inserted into coronary sinus to improve leaflet coaptation. In animal models of ischemic MR, this device has demonstrated to be effective [75,76] . Initial data from clinical trials have demonstrated safety and feasibility for the CARILLON device [77,78]. ...
There is an increasing number of patients with mitral regurgitation secondary to dilated cardiomyopathy. Ischemic mitral regurgitation is a common complication of left ventricular dysfunction related to chronic coronary artery disease: it is present in 10-20% of these patients and is associated with a worse prognosis also after coronary revascularization. Currently, coronary artery bypass grafting combined with restrictive annuloplasty is the most commonly performed surgical procedure, although novel approaches have been used with varying degrees of success. The suboptimal results obtained with the commonly used surgical approaches require the development of alternative surgical techniques with the aim to correct the causal mechanisms of the disease. In fact the pathophysiology of ischemic mitral regurgitation is multifactorial involving global and regional left ventricular remodeling, as well as the dysfunction and distortion of the components of the entire mitral valve apparatus. The purpose of this review is to present the current surgical techniques available for the treatment of ischemic mitral regurgitation and to discuss novel approaches to the repair of this complex disease. (www.actabiomedica.it).
... Real-time 3D echocardiographic methods have been used to evaluate non-planarity and area changes in the mitral annulus in animals and humans [87][88][89][90][91][92][93][94][95][96][97][98]. Extracted 3D images obtained with multiplane TEE can also be used to evaluate non-planarity and area changes of the mitral annulus in patients with an annuloplasty ring [99,100]. ...
Three-dimensional (3D) echocardiography has been conceived as one of the most promising methods for the diagnosis of valvular heart disease, and recently has become an integral clinical tool thanks to the development of high quality real-time transesophageal echocardiography (TEE). In particular, for mitral valve diseases, this new approach has proven to be the most unique, powerful, and convincing method for understanding the complicated anatomy of the mitral valve and its dynamism. The method has been useful for surgical management, including robotic mitral valve repair. Moreover, this method has become indispensable for nonsurgical mitral procedures such as edge to edge mitral repair and transcatheter closure of paravaluvular leaks. In addition, color Doppler 3D echo has been valuable to identify the location of the regurgitant orifice and the severity of the mitral regurgitation. For aortic and tricuspid valve diseases, this method may not be quite as valuable as for the mitral valve. However, the necessity of 3D echo is recognized for certain situations even for these valves, such as for evaluating the aortic annulus for transcatheter aortic valve implantation. It is now clear that this method, especially with the continued development of real-time 3D TEE technology, will enhance the diagnosis and management of patients with these valvular heart diseases.
... A percutaneous mitral annuloplasty device (CARILLON) has been designed to be inserted into coronary sinus to improve leaflet coaptation. In animal models of ischemic MR, this device has demonstrated to be effective [75,76] . Initial data from clinical trials have demonstrated safety and feasibility for the CARILLON device [77,78]. ...
There is an increasing number of patients with mitral regurgitation secondary to dilated cardiomyopathy. Recent data suggest that mitral regurgitation (MR) can be surgically corrected in heart failure with sym-ptomatic improvements and favourable reverse left ventricular remodeling. However, several questions remain to be answered, regarding the optimal man-agement of functional mitral regurgitation, the cor-rect timing of surgery and the choice of the surgical technique to perform in patients affected by dilated cardiomyopathy. In the setting of ischemic chronic cardiomyopathy, data derived from the recent litera-ture suggest that concomitant severe ischemic MR should be addressed during CABG to improve sur-vival and quality of life. Most surgeons perform con-comitant CABG and mitral valve surgery in patients with ischemic chronic cardiomyopathy and moderate to severe MR. In the setting of chronic dilated car-diomyopathy, most clinicians would agree that cor-rection of severe MR in heart failure is warranted, mostly due to a symptomatic benefit and reduction of number of re-hospitalizations. Moreover, reverse ven-tricular remodeling has been demonstrated with un-dersized annuloplasty rings and correction of MR: this could lead to improved contractility, reduction in left ventricular end-diastolic and end-systolic vol-umes, and finally to improved NYHA functional class. Recent large studies suggest that patients undergoing mitral valve repair had improved perioperative sur-vival, shorter length of stay, and improved long-term survival than those undergoing mitral valve replace-ment because the preservation of the subvalvular ap-paratus seems to result in superior left ventricular remodelling and in greater improvement in NYHA class. In the near future, data from multi-institutional, randomized prospective trials will help to elucidate many of the questions and concerns regarding repair of severe functional mitral regurgitation. Finally, technology applied to heart surgery is continually evolving and will allow more exciting cellular and novel device therapies for the treatment of functional mitral regurgitation secondary to dilated cardiomyo-pathy.
... En experimentos animales ha sido posible colocar dispositivos dentro del seno coronario que permiten reducir el diámetro del anillo alrededor de un 25%. 32,33 Esta técnica, que parece prometedora, aún no ha sido probada en humanos. ...
La ecocardiografía se ha convertido en el método principal para la evaluación de las enfermedades valvulares. En el caso de la valvulopatía mitral, el ecocardiograma provee información detallada acerca de la anatomía y función ventricular. El uso de este método nos ha permitido el ahondar en el conocimiento de los mecanismos que participan en la génesis de insuficiencia mitral. El eco no sólo nos permite detectar la presencia de insuficiencia mitral sino también cuantificar su severidad, la cual contribuye al pronóstico del paciente. La ecocardiografía intraoperatoria ha servido para guiar los procedimientos quirúrgicos de reparación y mejorar sus resultados. Las nuevas técnicas dirigidas al tratamiento percutáneo de la insuficiencia mitral se apoyan fuertemente en la ecocardiografía para el monitoreo en tiempo real de estos procedimientos.
... O Viacor é um dispositivo que inclui um cateter triplo lúmen com uma ponta de silicone maleável que é avançada até a porção proximal da veia interventricular anterior. A rigidez do cateter produz uma pressão significante, que é máxima na parte póstero-lateral do ânulo mitral, resultando na redução do diâmetro desse anel 89 , aumentando a coaptação dos folhetos. O estudo de viabilidade e segurança inicial foi o PTOLEMY-1, e no momento o PTOLEMY-2 está sendo realizado em alguns locais da Europa e Canadá. ...
... The 3D measurements of mitral leaflet coaptation by 3DQ, such as tenting height, tenting area (TA), coaptation length, and tethering angles, were determined in 3 anteroposterior planes (medial, middle, and lateral) perpendicular to the commissure-commissure plane in the midsystole frame ( Figure 2). [13][14][15] ...
-The impact of transcatheter aortic valve replacement (TAVR) on the mitral valve apparatus and factors influencing reduction of mitral regurgitation (MR) with or without mitral leaflet tethering after TAVR are poorly understood. The present three-dimensional transesophageal echocardiography (3DTEE) study aimed to further elucidate early changes in the structure and function of the mitral valve apparatus after TAVR.
-We analyzed 90 patients (Non-Tenting group: 56 patients and Tenting group: 34 patients) who underwent TAVR using the Edwards SAPIEN and had intra-procedural 3DTEE evaluation of the mitral valve. Of all patients, MR improved in 54%, remained the same in 38% and worsened in 8% one day after TAVR. There were no statistically significant differences in mitral annular three-dimensional parameters before and after TAVR in both groups. In the Tenting group, tenting area (p <0.01) and tenting height (p <0.01) were decreased and coaptation length was increased (p <0.05) after TAVR. In a multivariable analysis, the predictors of improved MR were the decrease of tenting area (Odds ratio: 8.15; 95% CI: 1.31-50.7; p <0.05) and the decrease of valvulo-arterial impedance (Zva) (Odds ratio: 7.57; 95% CI: 1.15-49.9; p <0.05) in the Tenting group, and the decrease of Zva (Odds ratio: 6.96; 95% CI: 1.24-39.2; p <0.05) in the Non-Tenting group.
-Mitral leaflet tethering was improved immediately by TAVR in patients with mitral leaflet tenting regardless of mitral annular geometry. Acute improvement in MR after TAVR is predominantly related to global left ventricular hemodynamics and mitral leaflet tethering change.
... Moreover, for prosthetic valve device approval, the Food and Drug Administration (FDA) mandates pre-clinical animal trials, using either porcine or ovine models, to demonstrate sufficient safety including performance and handling, as well as to study the efficacy of new valve devices [25]. While many disparate results between human and animal trials have been observed, the current assumption taken for heart valve device trials (such as for transcatheter valve intervention [26][27][28][29][30][31]) -porcine and ovine animal models are similar to those of aged humans -is still prevailing. ...
Objective: To characterize the mechanical properties of aged human anterior (AML) and posterior (PML) mitral leaflets. Materials and Methods: The AML and PML samples from explanted human hearts (n = 21, mean age of 82.62 ± 8.77 years old) were subjected to planar biaxial mechanical tests. The material stiffness, extensibility and degree of anisotropy of the leaflet samples were quantified. The microstructure of the samples was assessed through histology. Results: Both the AML and PML samples exhibited a nonlinear and anisotropic behavior with the circumferential direction being stiffer than the radial direction. The AML samples were significantly stiffer than the PML samples in both directions, suggesting that they should be modeled with separate sets of material properties in computational studies. Histological analysis indicated the changes in the tissue elastic constituents, including the fragmented and disorganized elastin network, the presence of fibrosis and proteoglycan/glycosaminoglycan infiltration and calcification, suggesting possible valvular degenerative characteristics in the aged human leaflet samples. Overall, stiffness increased and areal strain decreased with calcification severity. In addition, leaflet tissues from hypertensive individuals also exhibited a higher stiffness and low areal strain than normotensive individuals. Conclusion: There are significant differences in the mechanical properties of the two human mitral valve leaflets from this advanced age group. The morphologic changes in the tissue composition and structure also infer the structural and functional difference between aged human valves and those of animals.
... The vacuum runs the length of the therapy catheter lumen and divides into a three-way manifold, including a pressure line, vacuum pump with a blood-collection canister, and a saline bag with syringe for flushing purposes. Although preclinical trials demonstrated safe application of the Mobius II in swine, efficacy of the device is limited by a greater degree of annular dilation, which often results in suture dehiscence [11]. Therefore, further device development has been suspended, and no recent data are available. ...
... • CARILLON Mitral Contour System, Cardiac Dimensions, Kirkland, Washington, USA: il sistema è un dispositivo costituito da un cavetto in nitinolo con un sistema di ancoraggio prossimale e distale; una volta posizionato l'accorciamento del cavetto permette di ottenere una riduzione delle dimensioni dell'anulus mitralico. Il sistema ha mostrato buoni risultati nel modello sperimentale ed è stato impiantato in 5 pazienti 19,20 . ...
... Ischemic mitral regurgitation (IMR), a consequence of left ventricular dysfunction despite a structurally normal mitral valve, occurs in 19% of patients after myocardial infarction [2]. Chronic IMR is an independent predictor of mortality with a clear correlation to the degree of mitral regurgitation (MR): the greater the degree of MR, the worse the prognosis [3,4]. The repair of mitral and tricuspid incompetence with preservation of the native valve is a major target of modern valve surgery [5,6]. ...
Background
The prevalence of mitral regurgitation in cardiac diseases requires annuloplasty systems that can be implanted without excessive patient burden. This study was designed to examine the morphological and functional outcome of a new double helix mitral annuloplasty ring in an ovine model in comparison to the classical Carpentier-Edwards (CE) annuloplasty ring as measured by reduction of mitral regurgitation and tissue integration. The Medtentia annuloplasty ring (MAR) is a helical device that is rotated into the annulus self-restoring the valve geometry, enabling a faster fixation without the need of elaborate repair of the valve geometry. The ventricular part of the helical ring encircles the valve chords.
Methods
Twenty adult sheep were overpaced until 2+ level mitral valve regurgitation was achieved. Seven animals per group received either the MAR or the CE ring. Implantation was performed on-pump in a beating heart through the left atrial appendix. The animals were sacrificed 3.6 ± 0.3 months after surgery following an echocardiography for assessing mitral regurgitation as primary endpoint. The annuloplasty rings with surrounding tissue were harvested for histological analyses as secondary endpoints. The remaining six sheep received the MAR system and were sampled seven, nine or 12 months after surgery.
Results
Implantation time (p < 0.01) and perfusion time (p < 0.001) as clinical secondary endpoints were significantly shorter in the MAR group. Echocardiography follow-ups showed sufficient valve function repair in nearly all animals with a normalization of the ventricle diameters in both groups (group difference: p = 0.147). The weights of the hearts did not differ significantly. Histology revealed adequately covered atrial annuloplasty rings with functional endothelium and lack of excessive granulation tissue or fibrosis in all specimens. The ventricular projections of the MAR systems encircling the chordae tendineae were not completely covered with neointimal tissue, although in no case were microthrombi detected and no thromboembolic events were recorded.
Conclusions
The new MAR system is an easy to use annuloplasty system with a functional outcome comparable to that of the well–proven CE ring. Mitral valve regurgitation is effectively stopped both by restricting the pathological expansion of the annulus and by gathering the chords without thrombus formation.
Valvular heart disease remains as a major cause of morbidity and mortality in the aging population around the world. For patients with advanced, symptomatic disease, surgical open-heart valve replacement or repair remains the standard treatment with both excellent short- and long-term outcomes. However, there are many older patients that are not considered surgical candidates, especially those with comorbidities. Often medical management alone is not enough for these high-risk patients; thus, less-invasive transcatheter approaches for valve repair/implantation have been developed and are growing in use. This chapter will discuss advanced 3D imaging in such patients during the applications of such procedures.
Length of coronary sinus is important in the design of cannulation devices used in cardiac resynchronization therapy and percutaneous mitral valve annuloplasty. It displays gender and population variations that may account for the failure rate of these procedures. Cardiac conditions requiring these procedures are common in black African populations. Studies of the coronary sinus from African populations, however, are scarce and altogether absent for Kenya. The aim of the current study was to determine the length of coronary sinus among black Kenyans. Coronary sinuses of seventy-four hearts (43 males and 31 females) of adult age range (20-70years) black Kenyans obtained during autopsy were studied at the Department of Human Anatomy, University of Nairobi, Kenya. Heart samples were classified into male and female and weighed. Lengths of the heart, left atrio-ventricular groove and coronary sinus were measured in millimeters. The mean coronary sinus length was 39.55±5.32 mm while that of heart was 139.73±13.86 mm. The length of left atrio-ventricular groove length was 66.12±9.97 mm. The sinus occupied 60% of the groove and correlated positively with the length of the groove. The coronary sinus of the study population is shorter than those reported for Caucasian populations. The length correlated with that of the atrioventricular groove and the heart.
Objectives:
The purpose of our study is to verify, whether percutaneous mitral annuloplasty results in reverse remodeling in patients with functional mitral regurgitation (FMR) and impaired ejection fraction (EF) and to investigate which echo parameters may help in prediction of the efficacy of the procedure.
Background:
FMR exacerbates left ventricular (LV) dilatation and contributes to both LV remodeling and heart failure.
Methods:
We analyzed baseline and 1 month follow-up data in 22 consecutive patients with FMR, who underwent successful percutaneous trans-coronary venous mitral annuloplasty with the Carillon device.
Results:
Significant reduction of FMR echo parameters, including vena contracta (VC), effective regurgitant orifice area (EROA), and regurgitant volume (RV) were observed and maintained throughout 1 month follow up and did not correlate with baseline annular, LV or with the left atrial diameters. Baseline mitral tenting area correlated negatively with the relative improvement (% difference) of EROA (r = -0.5898) and RV (r = -0.4363), but not with VC (r = 0.1341). In addition, increased EF as well as a significant reduction in left ventricular diameters were noted. The increase in EF negatively correlated with the change in EROA (r = -0.50058), PISA (r = -0.5327), and RV (r = -0.5457). Baseline mitral tenting area significantly correlated with the 1 month change in EF (r = 0.5946) and stroke volume (r = 0.6913).
Conclusions:
The improvement of FMR after treatment with the Carillon device is associated with LV reverse remodeling and an increase in systolic performance, that correlates with the reduction in mitral regurgitation, being not dependent on baseline heart diameters. Mitral tenting area seems to be an important parameter in prediction of benefit from percutaneous mitral annuloplasty.
Mitral stenosis is an obstruction of blood flow from the left atrium to the left ventricle. It is generally caused by rheumatic heart disease [1, 2]. Other causes of mitral stenosis are: severe calcification of the valve leaflets, congenital defects of the mitral valve, systemic lupus erythematosus (SLE), tumors, left atrial thrombi, vegetations due to endocarditis, and causes linked to prior device implants.
In selected patient populations with valvular heart disease, minimally invasive surgical and transcatheter procedures are becoming an alternative to standard open surgical approaches. Because these procedures are characterized by limited or no direct exposure of the operative field, pre-procedural planning and intraoperative decision making rely heavily on image guidance.
Standard two-dimensional imaging with conventional angiography and echocardiography is integral part of the procedures, and novel three-dimensional (3D) imaging approaches are increasingly used for pre- and intraoperative visualization. Pre-procedural 3D imaging provides detailed understanding of the operative field for surgical/interventional planning, while subsequent integration of imaging during the procedure allows real-time guidance. These images are also used as inputs to computational modeling, which is fundamental to device design.
This chapter describes the role of advanced imaging for interventional guidance of valvular procedures and their input to computational models, based on the emerging experience with computed tomography and other modalities allowing 3D imaging, including C-arm computed tomography, echocardiography, and magnetic resonance imaging.
IntroductionPercutaneous annuloplastyPercutaneous edge-to-edge mitral repairConclusions
DisclosureReferences
Percutaneous aortic valve replacement and percutaneous mitral valve repair are emerging alternatives for high-risk patients with severe valve disease. Interventional cardiologists are faced with the challenge represented by this complex procedure. This practical guide specifically deals with a comprehensive knowledge of the techniques and approach to percutaneous treatment of left side cardiac valve disease and discusses the potential complications and expected or potential morbidity from the procedure.
Less invasive surgical and transcatheter procedures for valvular and structural heart disease are characterized by limited direct exposure of the operative field. Therefore pre-procedural planning and intra-operative decision-making increasingly relies on image guidance. The need for pre- and intra- operative visualization has been met by novel 3-dimensional imaging approaches. Pre-procedural 3-D imaging provides detailed understanding of the operative field for surgical/interventional planning. Subsequent integration of imaging during the procedure allows real-time guidance. This chapter describes the emerging experience with computed tomography for interventional guidance of valvular procedures. Other modalities allowing 3-D imaging, including rotational angiography (C-arm CT), echocardiography, and MRI are briefly compared, but are discussed in more detail in other chapter of the book.
The causes of mitral regurgitation are numerous; they can be grouped in three main categories, as popularized by Alain Carpentier. The natural history of chronic MR is highly variable, depending of the volume of regurgitation, the LV function, and the underlying cause of MR. Chronic severe MR is associated with a 1% per year risk of major complications which include congestive heart failure, infective endocarditis, cerebrovascular events due to LA enlargement and development of AF, need for mitral valve surgery, and death. Echocardiography is essential for establishing the presence of MR, quantitate its severity and hemodynamic consequences, determine its etiology and assess the potential for repairability. The only effective treatment of chronic severe MR is surgical repair or replacement of the mitral valve. The indications for surgery are based on natural history data. The medical treatment is limited to the management of heart failure (ACE inhibitors, diuretics) and AF (anticoagulation). The optimal timing of corrective surgery is determined by the severity of MR, the presence of symptoms, the LV systolic function, the feasibility of valve repair, the presence of AF, the presence of PHT, and fi nally the preference and expectations of the patient (see figure 2). Whenever feasible, mitral valve repair is the preferred surgical treatment for MR. It is associated with a very lower operative mortality, particularly in asymptomatic individuals aged 65 years or less, and a better overall survival at 10 years (68 vs 52 %) than mitral valve replacement.
The study was to observe hemodynamic alterations of cardiac function to design a model of canine mitral valve insufficiency (MVI) based on chordae tendinae rupture (CTR). Ten healthy beagles with normal heart function were used in this study. To measure hemodynamics, the patient monitor was equipped for invasive blood pressure and a Swan-Ganz catheter. Hemodynamic alterations were checked promptly during CTR procedures. MVI model was made by transection of the chordae tendinae with small arthroscopy hook knife through 5th intercostal open chest. Color Doppler at the level of the mitral valve showed high-velocity regurgitant flow immediately after CTR at intraoperative echocardiography. In hemodynamic measurements, pulmonary capillary wedge pressure (PCWP) was significantly increased, while mean arterial pressure (MAP), venous pressure (VP), pulmonary arterial pressure (PAP), cardiac output (CO) and cardiac index (CI) were significantly decreased after CTR. It was known that the left atrium was overloaded by regurgitant volume from the left ventricle. In conclusion, the MVI model induced by CTR technique in this study should be used as suitable one for the effective research of canine mitral valve disease. Further study should be needed to measure the chronic alternation of mitral valve in the model. © 2014, Korean Society of Veterinary Clinics. All rights reserved.
Recent advances in a number of surgical and catheter-based therapeutic approaches in cardiology have allowed less invasive treatment with a better prognosis even in complex cases. These techniques include electrophysiological examination and ablation, surgical and transcatheter mitral valve repair as well as transfemoral aortic valve implantation, and percutaneous closure of atrial appendage, septal defects, and paravalvular leaks.
In most countries, cardiovascular disease is one of the leading causes of death. The treatment and management of cardiovascular disease has advanced over the past 2 decades, largely due to the use of experimental animal models. Although a large amount of information can be generated with the use of experimental animal models, non-human animal models cannot fully replicate the complexity of human pathological conditions. Thus, a deeper understanding of the differences and similarities between humans and each animal model is important in preclinical research. Small animal models provide insight into the molecular and cellular basis of cardiovascular biology, but significant differences exist with regard to cardiovascular characteristics between small animal models and humans. Large animal models which simulate human cardiovascular physiology, anatomy and function are also crucial to develop clinical therapies and interventions. Here, we will mainly focus on the large animal models of cardiovascular disease, including coronary artery disease, heart failure, peripheral artery disease and structural heart disease.
The distribution of mitral stenosis (MS) in the general population is closely associated with rheumatic fever, since it is its main cause. Recent data of the World Health Organisation (WHO) suggest that acute rheumatic fever and, as a consequence, rheumatic disease, affect about 15.6 million people throughout the world. Females are affected more frequently than males with a ratio ranging between 2:1 and 3:1 [1].
Mitral regurgitation is increasing in Europe despite the reduction in the incidence of rheumatic disease. The development of surgical mitral valve repair by Alain Carpentier has changed the management and prognosis of patients with severe mitral regurgitation. Imaging techniques provide precise information on the type and extent of anatomic lesions, mechanisms of regurgitation, etiology, amount of regurgitation, and reparability of the valve. Two-dimensional transesophageal echocardiography is routinely used for planning mitral valve surgery. However, this technique has several potential pitfalls with regards to spatial relationships and valvular morphological abnormalities. Recently introduced, live, real-time three-dimensional transesophageal echocardiography has improved our understanding of the functional anatomy and pathophysiology of mitral valve disease, especially in functional mitral regurgitation. Nowadays, three-dimensional transesophageal echocardiography is a powerful tool, not only for the accurate diagnosis of mitral lesions, but also for the intraoperative monitoring and the guidance of invasive procedures in the catheterization laboratory. It allows evaluating online all cardiac structures and offers new views like the “surgeon view” of the mitral valve morphology with only one acquisition. The aims of this article are to review the contribution of two-dimensional and three-dimensional transesophageal echocardiography to the evaluation of the mitral valve functional anatomy and to summarize their clinical applications and therapeutic implications.
Zusammenfassung Gegenwrtig existieren nur wenig Daten zu Vernderungen der Myokardfunktion nach koronarchirurgischem Eingriff und einem sog.Downsizingder Mitralklappe (MK) bei Patienten mit relevanter chronisch ischmischer Mitralklappeninsuffizienz (Ischemic Mitral Valve Regurgitation=IMR) und eingeschrnkter linksventrikulrer (LV) Funktion. Bei 63 Patienten (Alter: 719 Jahre) mit koronarer Herzkrankheit (KHK), chronischerIMRGrad 3-4 und ischmischer Kardiomyopathie (LV-Ejektionsfraktion (LVEF): 309%) erfolgte ein chirurgisches Vorgehen aus MK-Downsizingum 2–4 (2,70,7) Annuloplastie-Ringgren und Koronarrevaskularisation. Zur Ermittlung der berlebensrate, des postoperativen Funktionsstatus (New York Heart Association=NYHA), dem MK-Insuffizienzgrad und Vernderungen der Myokardfunktion wurden klinische und echokardiographische Untersuchungen mit Bestimmung der linksventrikulren und linksatrialen (LA) Dimensionen, Volumina und Volumenindexe (LVESD, -EDD; LVESV, -EDV; LVESVI, -EDVI) sowie von Verkrzungsfraktion (FS) und LVEF durchgefhrt. Die postoperative 30-Tage-Letalitt betrug 1,6%, die berlebensrate nach 31 Monaten 95% und nach 21 Jahren 83%. Postoperativ kam es zu einer signifikanten Verbesserung derNYHA-Klasse von 3,40,6 auf 1,50,6 (pIMR-Rezidiv trat nicht auf. Auerdem konnte eine signifikante Verkleinerung der LV-/LA-Dimensionen, -Volumina und -Volumenindexe im Sinne einesReverse Remodelingmit einem Anstieg von FS und LVEF dokumentiert werden. Auch bei Patienten mit properativ bereits erheblich eingeschrnkter LV-Funktion (LVEF ≤25%, n=23) waren diese positiven Vernderungen nachweisbar. Ein kombiniertes chirurgisches Vorgehen aus MK-Downsizingund Koronarrevaskularisation fhrte bei geringer perioperativer Letalitt und ohne Auftreten einesIMR-Rezidivs zu einer signifikanten Verbesserung der LV-Funktion.
The ischemic mitral regurgitation is defined by a left ventricular muscle disease affecting the function of normal mitral valve leaflets. This kind of mitral regurgitation is founded in about 20% of the ischemic cardiomyopathy and is attributed to the remodelling of the left ventricular shape. Its development is associated to a significantly worse prognosis. Frequently this ischemic mitral regurgitation will be associated to episode of acute heart failure decompensation. Its diagnosis is sometimes challenging as the degree of regurgitation might be extremely variable and affected by loading conditions. Echocardiography and especially exercise stress echocardiography has been demonstrated as an extremely powerful tool for its diagnosis and the prognostic evaluation. Its treatment should include the pharmacological treatment of the chonic heart failure and we are still waiting data in regard to the prognostic role of surgical mitral valvuloplastie. Works are still ongoing.
Background and Objectives:In clinical practice, significant recurrence of mitral regurgitation (MR) is ob- served frequently even after surgical treatment for ischemic MR (IMR). The purpose of this study is to evaluate the recurrence rate of MR and to investigate perioperative predictors for its recurrence following surgery for IMR. Subjects and Methods:We retrospectively analyzed 106 patients who underwent surgical management for IMR. Echocardiographic parameters, such as severity of MR, ejection fraction, diastolic left ventricular (LV) dimen- sion, systolic LV dimension, left atrial size, LV sphericity index, mitral valve (MV) tenting area, MV tenting height (TH), tethering distance, MV intraleaflet angle (MVILa), and MV intraleaflet height (MVILh) were me- asured. Results:Two types of surgery were performed to treat IMR, including valvuloplasty combined with coronary artery bypass graft (CABG)(group A, n=79) and LV volume reduction surgery combined with CABG (group B, n=27). Significant MR was detected echocardiographically 5.4±6.7 months after the surgery. The overall recurrence rate of MR was 17% (n=18), and 15.2% (n=12) in group A and 22.2% (n=6) in group B. The preoperative TH and the postoperative MVILh were independent perioperative predictors for the recurrence of significant MR according to multiple logistic regression analysis (p
This article contains a review of the most significant publications on non-invasive recent cardiac imaging techniques in 2005. The increasing importance of technological innovation in echocardiography is reflected in the sections on three dimensional echocardiography, contrast echocardiography, and myocardial deformation measurement techniques (i.e., strain echocardiography). The most important developments affecting cardiology in the techniques of magnetic resonance imaging and multidetector computed tomography are also summarized. This review ends with a detailed description of the contributions made by imaging techniques to the diagnosis of aortic disease.
Recent developments in three-dimensional echocardiography have made it possible to obtain images in real time, without the need for off-line reconstruction. These developments have enabled the technique to become an important tool for both research and daily clinical practice. A substantial proportion of the studies carried out using three-dimensional echocardiography have focused on the mitral valve, the pathophysiology of mitral valve disease and, in particular, functional mitral regurgitation. The aims of this article were to review the contribution of three-dimensional echocardiography to understand the functional anatomy of the mitral valve and to summarize the resulting clinical applications and therapeutic implications.
The mitral valve is a complex, bi-leaflet structure that separates the left atrium (LA) and the left ventricle (LV). It consists
of two leaflets, a fibrous annulus, chordae tendinae, two papillary muscles, and their left ventricular attachments (Fig.
3.1).
Recent innovations have occurred in the treatment of valvular heart disease so that we now stand at the very beginning of
a field that is likely to show considerable growth in the future. These innovations include the introduction of self-expanding
and balloon-expandable stents containing bioprosthetic heart valves, and other valvular implants and techniques for the repair
and treatment of valvular heart disease. Previously, the field of nonsurgical cardiac valve repair and replacement consisted
solely of the use of balloon valvuloplasty for valvular stenosis. The ability to address aortic stenosis more definitively
than with balloon valvuloplasty and to address regurgitant valve lesions will greatly expand the patients who can be treated
without surgery. Percutaneous valve repair and replacement is at an early stage with a variety of techniques that are undergoing
investigation. Similar to the initial development of balloon angioplasty for coronary artery disease, improvements in technology,
techniques, and experience will be necessary before we can reproduce the excellent results achieved today with surgery.
Demographic change presents great challenges to medicine. Especially, heart disease has become more common as people live
longer. In addition to other age-related physiological changes to the coronary vasculature, mitral valve disease in elderly
has become center of attention for a rapidly expanding research in this field. The etiology in such population refers to the
cause of the disease or syndrome (e.g., degenerative, rheumatic, ischemic), to the abnormalities of components of the mitral
valve apparatus (e.g., chordal rupture, elongated chordae, excess leaflet tissue, dilated annulus) and the combinations of
lesions leading to different types of valve dysfunction (e.g., leaflet prolapsed or restriction). Today, increasing numbers
of elderly patients are referred for mitral valve surgery but still it has been unclear whether the results offset the risk
of intervention in such patient population. The current chapter will examine, in elderly patients, the myriad surgical options
with focus on clinical outcomes, advantages of repair versus replacement, the quality of life and survival benefits of surgery
compared to medical management. Notably, an open question that concerns is the disease-independent influence of the biological
aging process and therefore associated operative risk. This is also focused in this chapter by examining selected literature.
KeywordsSurgery-Mitral valve disease-Degenerative regurgitation-Mitral leaflets-Replacement-Alfeiri repair-Mitral valve repair-Octogenarians-Carpentier’s triad-Endocarditis
The predominant cause of mitral stenosis is rheumatic heart disease.
The most frequent ECG abnormality with mitral stenosis is atrial fibrillation.
The occurrence of atrial fibrillation (or atrial flutter) in the patient with atrial fibrillation requires anticoagulation initially by heparin followed by coumadin and often of treatment aiming at control of rapid ventricular response using digoxin, beta-blockade, and calcium-channel blockade.
Guidance by transesophageal echocardiography (TEE) is useful to rule out atrial thrombus before cardioversion.
Prolapse of the mitral valve is a fall below its normal position, and billowing (bulge beyond its normal place) of the mitral valve is an abnormal movement of the mitral valve during systole beyond its normal position and into the left atrium.
Often mitral valve prolapse is a progressive disease with flail leaflets and chordal rupture being found in older patients.
Mitral insufficiency is an organic mechanism if there is intrinsic mitral valve disease or a functional mechanism if the valve is structurally normal but regurgitates due to an extravalvular abnormality.
Surgical correction of mitral regurgitation (MR) is indicated in patients with severe MR and symptoms or with reduced LV systolic function.
Prevention of infective endocarditis using the appropriate antibiotic prophylaxis is necessary in patients with MR.
The most frequent cause of mortality after surgical correction of MR is left ventricle dysfunction due to chronic irreversible myocardial damage.
Papillary muscle dysfunction (PMD) has been implicated in the pathogenesis of ischemic mitral regurgitation (MR). We hypothesized that ischemic MR is not caused by PMD and/or dysfunction of the myocardial regions from where the papillary muscles arise but is related to reduction in global left ventricular (LV) function. To test this hypothesis, three groups of dogs were studied.
In group 1 dogs (n = 8), varying degrees of regional and global LV dysfunction were produced. In group 2 dogs (n = 7), the circulation to the papillary muscles was isolated from that of the rest of the LV. Dysfunction of one or both papillary muscles was produced without producing global LV dysfunction. Global LV dysfunction was also produced while keeping papillary muscle function intact. The degree of MR (assessed using contrast echocardiography) was correlated in both groups of dogs with thickening of the papillary muscles and regional and global LV function. In the group 3 dogs (n = 6), the spatial distribution of blood flow within each papillary muscle was determined during ischemia by using radiolabeled microspheres. Thickening of the papillary muscles was assessed at three different levels along their lengths and was correlated with average blood flow at these levels. In group 1 dogs, MR was noted only when global LV function was affected and its severity correlated inversely with global LV function (r = -0.84 with peak positive LV dP/dt and r = -0.95 with global LV thickening, respectively). In comparison, there was poor correlation between MR and anterior and posterior papillary muscle thickening (r = -0.38 and r = -0.49, respectively). In group 2 dogs, MR did not occur in the presence of either PMD or akinesia of the immediately adjacent LV myocardium. MR occurred only when global LV dysfunction was produced (with the papillary muscle function intact), and its severity correlated inversely with global LV function (r = -0.92 with LV dP/dt and r = -0.86 with global LV thickening, respectively). There was poor correlation between the degree of MR and thickening of the anterior and posterior papillary muscles (r = -0.24 and r = -0.38, respectively). In both groups of dogs, MR was associated with incomplete mitral leaflet closure (IMLC), and the severity of MR correlated linearly with the degree of IMLC (r = 0.98). MR was never associated with mitral valve prolapse. In the group 3 dogs, despite more inhomogeneous flow during ischemia to the anterior compared with the posterior papillary muscle, mean thickening of these muscles was similar (3 +/- 10% and 3 +/- 4%, respectively). Furthermore, there was minimal variability in thickening between different parts of the muscles (3 +/- 2% and 5 +/- 3%, respectively).
It is concluded that PMD and/or dysfunction of the immediately adjacent LV myocardium does not result in MR. MR occurs during ischemia only when global LV function is affected, even when thickening of the papillary muscles and the immediately adjacent LV remains intact. MR in this situation is related to IMLC; the greater the degree of IMLC, the greater the MR. These findings suggest that the mechanism of ischemic MR is not related to PMD. There may also be important therapeutic implications of these findings.
Mitral regurgitation is a frequent finding in patients with end-stage cardiomyopathy predicting poor survival. Conventional treatment consists medical treatment or cardiac transplantation. However, despite severely decreased left ventricular function, mitral annuloplasty may improve survival and reduce the need for allografts.
From January 1996 to July 2002, 121 patients with severe end-stage dilated (DCM) or ischemic cardiomyopathy (ICM), mitral regurgitation > or =2, and left ventricular ejection fraction < or =30% underwent mitral valve annuloplasty using a flexible posterior ring. DCM was diagnosed in 30 patients (25%), whereas ICM was found in 91 patients (75%). Concomitant tricuspid valve repair was performed in 14 (46.6%) patients in the DCM, and in 11 (12%) in the ICM group (P=0.0001), coronary artery bypass grafting in three (10%) in the DCM, and in 78 patients (86%) in the ICM group (P<0.00001). The mean follow-up time was 567+/-74 days in the DCM and 793+/-63 days in the ICM group (ns).
Early mortality was 6.6% (8/121), and was equal for both groups. Improvement in NYHA class (DCM 3.3+0.1-1.8+/-0.16; ICM from 3.2+0.04 to 1.7+/-0.07) were equal between groups after 1 year. Seventeen (15%) late deaths occurred during the follow-up period. There was no difference in the 2-year actuarial survival between groups (DCM/ICM 0.93/0.85). Risk factors for mitral reconstruction failure, defined as regurgitation > or =2 after 1 year, were preoperative NYHA IV in the DCM group (P=0.03), a preoperative posterior infarction (P=0.025), decreased left ventricular function (P=0.043), larger ring size (P=0.026) and preoperative renal failure (P=0.05) in the ICM group. Risk factors for death were larger ring size (P=0.02) and an increased LVEDD (P=0.027) in the DCM group and the postoperative use of IABP (P=0.002), renal failure (P=0.001), and a larger preoperative LVESD (P=0.035) in the ICM group.
Mitral reconstruction with a posterior annuloplasty using a flexible ring is effective in patients with severely depressed left ventricle function and has an acceptable operative mortality. Mid-term results are superior to medical treatment alone and comparable to cardiac transplantation.
Mitral regurgitation (MR) frequently accompanies congestive heart failure (CHF) and is associated with poorer prognosis and more significantly impaired symptomatic status. Although surgical mitral valve annuloplasty has the potential to offer benefit, concerns about the combined surgical risk and possible effects on ventricular performance have limited progress. We evaluated the feasibility and short-term efficacy of a novel device placed in the coronary sinus to reduce MR in the setting of CHF.
CHF and MR were induced in 9 adult sheep by rapid ventricular pacing for 5 to 8 weeks. A mitral annular constraint device was implanted percutaneously through the right internal jugular vein in the coronary sinus and great cardiac vein to create a short-term stable reduction (24.9+/-2.5%) in the mitral annular septal-lateral dimension as assessed echocardiographically. Right and left heart pressures and cardiac output were determined before and 15 minutes after device implantation. MR extent was examined echocardiographically and expressed as a ratio of left atrial area (MR/LAA). After device placement, MR was substantially reduced from an MR/LAA of 42+6% to 4+/-3% (P<0.01). In association, mean pulmonary wedge pressure was significantly reduced (26+/-3 to 18+/-3 mm Hg; P<0.01) and mean cardiac output significantly increased (3.4+/-0.3 to 4.3+/-0.4 L/min; P=0.01).
In this model of CHF, percutaneous placement of a mitral annular constraint device in the coronary sinus resulted in the short-term elimination or minimization of MR and was accompanied in the short term by favorable hemodynamic effects.
More precise understanding of annular remodeling in the evolution of chronic ischemic mitral regurgitation is needed to provide a more rational basis for optimal annuloplasty ring sizing and selection as well as the design of new reparative techniques. Three-dimensional in vivo data describing these geometric perturbations however are lacking. Using an ovine model of chronic myocardial infarction we determined the three-dimensional distortions of the mitral annulus associated with the development of chronic ischemic mitral regurgitation.
Ten sheep underwent placement of radiopaque markers on the left ventricle and mitral annulus as well as placement of snares around the second and third obtuse marginal coronary arteries. After 8 days biplane cinefluoroscopy provided three-dimensional marker data and snare occlusion created an inferior infarction. After 7 more weeks the animals were studied again.
Severity of mitral regurgitation increased (0.6 +/- 0.5 to 2.5 +/- 0.7). Septal-lateral (2.99 +/- 0.20 cm to 3.64 +/- 0.35 cm, maximum dimension) and commissure-commissure (3.71 +/- 0.32 cm to 4.40 +/- 0.30 cm) mitral annular diameters and the lengths of the muscular (7.77 +/- 0.39 cm to 9.51 +/- 0.72 cm) and fibrous annular perimeters (3.36 +/- 0.37 cm to 3.85 +/- 0.39 cm, p < 0.0001 for all) increased while the height of the annular "saddle horn" above a best-fit plane fell (0.73 +/- 0.52 cm to 0.57 +/- 0.42 cm, minimum dimension, p = 0.01).
These three-dimensional in vivo data reflect annular remodeling in chronic ischemic mitral regurgitation and suggest that mitral repair in this context should be aimed at preventing further lengthening of the intertrigonal distance, reducing the septal-lateral annular diameter to reestablish adequate leaflet coaptation, and restoring the saddle shape of the annulus.
Background— This study was conducted to elucidate the geometric differences of the mitral apparatus in patients with significant mitral regurgitation caused by ischemic cardiomyopathy (ICM-MR) and by idiopathic dilated cardiomyopathy (DCM-MR) by use of real-time 3D echocardiography (RT3DE).
Methods and Results— Twenty-six patients with ICM-MR caused by posterior infarction, 18 patients with DCM-MR, and 8 control subjects were studied. With the 3D software, commissure-commissure plane and 3 perpendicular anteroposterior (AP) planes were generated for imaging the medial, central, and lateral sides of the mitral valve (MV) during mid systole. In 3 AP planes, the angles between the annular plane and each leaflet (anterior, Aα; posterior, Pα) were measured. In ICM-MR, Aα measured in the medial and central planes was significantly larger than that in the lateral plane (39±5°, 34±6°, and 27±5°, respectively; P<0.01), whereas Pα showed no significant difference in any of the 3 AP planes (61±7°, 57±7°, and 56±7°, P>0.05). In DCM-MR, both Aα (38±8°, 37±9°, and 36±7°, P>0.05) and Pα (59±6°, 58±5°, and 57±6°, P>0.05) revealed no significant differences in the 3 planes.
Conclusions— The pattern of MV deformation from the medial to the lateral side was asymmetrical in ICM-MR, whereas it was symmetrical in DCM-MR. RT3DE is a helpful tool for differentiating the geometry of the mitral apparatus between these 2 different types of functional mitral regurgitation.
Objectives
We sought to test whether isolated mitral annular (MA) dilation can cause important functional mitral regurgitation (MR).
This study tests the hypothesis that neither small nor large myocardial infarctions that include the anterior papillary muscle produce mitral regurgitation in sheep.
Coronary arterial anatomy to the anterior left ventricle and papillary muscle was determined by dye injection in 41 sheep hearts and by triphenyl tetrazolium chloride in 13. Development of acute or chronic mitral regurgitation and changes in left ventricular dimensions were studied by use of transdiaphragmatic echocardiography in 21 sheep after infarction of 24% and 33% of the anterior left ventricular mass. These data were compared with previous data from large and small posterior left ventricular infarctions.
Ligation of two diagonal arteries infarcts 24% of the left ventricular mass and 82% of the anterior papillary muscle. Ligation of both diagonals and the first circumflex branch infarcts 33% of the left ventricle and all of the anterior papillary muscle. Neither infarction causes mitral regurgitation, although left ventricular cavity dimensions increase significantly at end systole. After the smaller infarction, the left ventricular cavity enlarges 150% over 8 weeks without mitral regurgitation.
In sheep small and large infarctions of the anterior wall that include the anterior papillary muscle do not produce either acute or chronic mitral regurgitation despite left ventricular dilatation. In contrast large posterior infarctions produce immediate mitral regurgitation owing to asymmetric annular dilatation and discoordination of papillary muscle relationships to the valve. After small posterior infarctions that include the posterior papillary muscle, mitral regurgitation develops because of annular and ventricular dilatation during remodeling.
Ischemic mitral regurgitation is a serious and increasingly common clinical disorder, but at present, little is known of the associated prognostic implications, especially in specific therapeutic subgroups. Over a 6.5-year period beginning January 1, 1981, postinfarction mitral regurgitation was demonstrated ventriculographically in 2,343 (19%) of 11,748 patients having significant coronary artery disease defined at cardiac catheterization. Moderate or severe regurgitation was observed in 381 (3%), and among these patients, four treatment groups were defined: Group I (medical, n = 165), Group II (reperfusion, n = 63), Group III (coronary artery bypass only, n = 94), and Group IV (valve replacement or repair in addition to coronary bypass, n = 59). Multivariable regression analysis of survival data in the overall population and in specific treatment groups was performed with the Cox proportional hazards model. Defined and undefined selection biases precluded formal quantitative survival comparisons among some treatment groups; however, unadjusted and adjusted survival analysis for each group revealed several interesting concepts. First, increasing severity of mitral regurgitation had a progressively negative impact on survival prognosis regardless of treatment. Congestive heart failure, the number of associated disorders, acute presentation requiring cardiac care unit admission, diminished ejection fraction, increasing coronary obstruction, and advanced age all worsened prognosis (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
A large animal model of ischemic mitral regurgitation (MR) that resembles the multiple presentations of the human disease was developed in sheep. In 76 sheep hearts, the anatomy of the coronary arterial circulation was determined by observation and polymer casts. Two variations, types A and B, which differed by the vessel that supplied the left ventricular apex, were found. In all hearts, the circumflex coronary artery has three marginal branches and terminates in the posterior descending coronary artery. The amount and location of left ventricular (LV) mass supplied by each marginal circumflex branch was determined by dye injection and planimetry. In type A hearts, ligation of the first and second marginal branches infarcts 23% +/- 3.0% of the LV mass, does not infarct either papillary muscle, significantly (p < 0.001) increases LV cavity size 48% at the high papillary muscle level by 8 weeks, and does not cause MR. Ligation of the second and third marginal branches infarcts 21.4% +/- 4.0% of the LV mass, includes the posterior papillary muscle, significantly increases (p < 0.001) LV cavity size 75%, and causes severe MR by 8 weeks. Ligation of the second and third marginal branches and the posterior descending coronary artery infarcts 35% to 40% of the LV mass, increases LV cavity size 39% within 1 hour, and causes massive MR. After moderate (21% to 23%) LV infarction, development of ischemic MR requires both LV dilatation and posterior papillary muscle infarction; neither condition alone produces MR. Large posterior wall infarctions (35% to 40%) that include the posterior papillary muscle produce immediate, severe MR.(ABSTRACT TRUNCATED AT 250 WORDS)
Mitral regurgitation (MR) may complicate acute myocardial infarction (MI). However, it is not known whether mild MR is an independent predictor of post-MI outcome.
The study cohort consisted of 727 Survival and Ventricular Enlargement Study patients who underwent cardiac catheterization, including left ventriculography, up to 16 days after MI. Left ventriculograms were analyzed for diastolic and systolic volumes, global left ventricular sphericity, extent of wall motion abnormality, and endocardial curvature. The presence of MR was related to the risk of developing a cardiovascular event during 3.5 years of follow-up. MR was present in 141 patients (19.4%). Severe (3+) MR was present in only 2 patients. Patients with MR were more likely to have a persistently occluded infarct artery (MR versus no MR, 27.3% versus 15.2%; P=.001). Although the ejection fractions were similar, MR patients had larger end-systolic and end-diastolic volumes and more spherical ventricles than patients without MR. Sphericity change from diastole to systole was also significantly reduced in MR patients. Patients with MR were more likely to experience cardiovascular mortality (29% versus 12%; P<.001), severe heart failure (24% versus 16%; P=.0153), and the combined end point of cardiovascular mortality, severe heart failure, or recurrent myocardial infarction (47% versus 29%; P<.001). The presence of MR was an independent predictor of cardiovascular mortality (relative risk, 2.00; 95% CI, 1.28 to 3.04).
Mild MR is an independent predictor of post-MI mortality. As such, it adds important information for risk stratification of post-MI patients.
Acute posterior myocardial infarction that produces immediate mitral regurgitation alters the mitral annulus and its spatial relationship with both papillary muscles. The precise deformations that cause valve insufficiency are not understood and impair efforts to repair the valve.
In six Dorsett hybrid sheep, sonomicrometry transducers were placed around the mitral annulus (6) and at the tips and bases of both papillary muscles (4). Two weeks later, three branches of the circumflex coronary artery were occluded to infarct approximately 32% of the posterior left ventricle. This infarction produced acute 2 to 3+ mitral regurgitation in all animals, as determined by color flow Doppler velocity mapping. Before and after infarction, distance measurements between sonomicrometry transducers were used to produce the three-dimensional coordinates of each transducer every 5 ms. After infarction, the area of the annulus increased only 9.2+/-6.3% at end systole (ES). In addition, the normal shortening of the posterior papillary muscle was obliterated to allow its tip to move 1.4+/-0.6 mm closer to the centroid of the annulus at ES. After infarction, the anterior papillary muscle continued to shorten normally, but at ES, its tip and base were 0.9+/-0.7 mm and 1.3+/-0.7 mm farther from the centroid, respectively.
These deformations tend to produce a relative prolapse of leaflet tissue attached to the posterior papillary muscle and restriction of leaflet tissue attached to the anterior papillary muscle. This papillary muscle discoordination with minimal annular dilatation distorts leaflet coaptation sufficiently to produce severe mitral regurgitation.
To determine whether precise left-sided accessory pathway localization is possible from the coronary sinus, electrocardiogram (ECG) characteristics from the coronary sinus pair demonstrating earliest activation via the accessory pathway were compared to simultaneous mitral annular ablation catheter ECGs at successful ablation sites in 48 patients. To define the coronary sinus-mitral annular relation, the coronary sinus to mitral annulus distance (D) was measured at sequential distances from the coronary sinus os in 10 cadaver hearts. Mitral annular ECGs demonstrated earliest activation via the accessory pathway more frequently than the earliest coronary sinus pair (p < 0.001), more frequent continuous electrical activity (p < 0.001), and more frequent accessory pathway potentials (p < 0.01). D was >10 mm at 20, 40, and 60 mm, respectively, from the coronary sinus os. Coronary sinus ECGs do not precisely localize left-sided accessory pathways, which may be due in part to an average anatomic separation of more than 10 mm between the coronary sinus and accessory pathways bridging the mitral annulus.
Functional mitral regurgitation (FMR) occurs with a structurally normal valve as a complication of systolic left ventricular dysfunction (LVD). Determinants of degree of FMR are poorly defined; thus, mechanistic therapeutic approaches to FMR are hindered.
In a prospective study of 21 control subjects and 128 patients with LVD (defined as ejection fraction <50%, mean 31+/-9%) in sinus rhythm, we quantified simultaneously by echocardiography the effective regurgitant orifice (ERO) of FMR by using 2 methods: mitral deformation (valve and annulus) and left ventricular (LV) global (volumes, stress, function, and sphericity) and local (papillary muscle displacements and regional wall motion index) remodeling. A wide range of ERO (15+/-14 mm(2), 0 to 87 mm(2)) was observed, unrelated to ejection fraction (P:=0.32). The major determinant of ERO was mitral deformation, ie, systolic valvular tenting and annular contraction in univariate (r=0.74 and r=-0.61, respectively; both P:<0.0001) and multivariate (both P:<0. 0001) analyses, independent of global LV remodeling. Systolic valvular tenting was strongly determined by local LV alterations, particularly apical (r=0.75) and posterior (r=0.70) displacement of papillary muscle, with confirmation in multivariate analysis (both P:<0.0001), independent of LV volumes, function, and sphericity.
The presence and degree of FMR complicating LVD are unrelated to the severity of LVD. Local LV remodeling (apical and posterior displacement of papillary muscles) leads to excess valvular tenting independent of global LV remodeling. In turn, excess tenting and loss of systolic annular contraction are associated with larger EROs. These determinants of FMR warrant consideration for specific approaches to the treatment of FMR complicating LVD.
The perturbed mitral leaflet geometry that leads to acute ischemic mitral regurgitation during acute left ventricular ischemia has not been quantified, nor is it known whether annuloplasty rings affect these detrimental changes in leaflet geometry.
Radiopaque markers were implanted on both mitral leaflets and around the anulus in 3 groups of sheep: one group without rings served as the control group (n = 7); the others underwent Duran (n = 6; Medtronic Heart Valve Division, Minneapolis, Minn) or Carpentier-Edwards Physio (n = 5; Baxter Cardiovascular Division, Santa Ana, Calif) ring annuloplasty. After recovery, 3-dimensional marker coordinates were obtained by means of biplane videofluoroscopy before and during acute posterolateral left ventricular ischemia. Leaflet geometry was defined by measuring distances between annular and leaflet markers and perpendicular distances to the leaflet markers from a best-fit annular plane.
In all control animals, left ventricular ischemia was associated with acute ischemic mitral regurgitation and apical displacement (away from the annular plane) of the posterior leaflet edge and base markers by 0.6 +/- 0.4 mm (P =.01) and 0.7 +/- 0.2 mm (P <.001), respectively. The distance between the posterior leaflet markers and the mid-posterior anulus did not change significantly during ischemia. The anterior leaflet edge marker extended 1.0 +/- 0. 5 mm (P =.01) away from the mid-anterior anulus during ischemia, but compared with its nonischemic position, the anterior leaflet was not displaced apically away from the annular plane. In all animals in the Duran and Physio groups, leaflet geometry was unchanged during ischemia, and acute ischemic mitral regurgitation was not detected.
Acute ischemic mitral regurgitation was associated with restricted motion of the posterior leaflet and extension of the anterior leaflet. Annuloplasty rings prevented these geometric perturbations of the mitral leaflets during acute left ventricular ischemia and preserved valvular competence.
This study aimed to separate proposed mechanisms for segmental ischemic mitral regurgitation (MR), including left ventricular (LV) dysfunction versus geometric distortion by LV dilation, using models of acute and chronic segmental ischemic LV dysfunction evaluated by three-dimensional (3D) echocardiography.
Dysfunction and dilation-both mechanisms with practical therapeutic implications-are difficult to separate in patients.
In seven dogs with acute left circumflex (LCX) coronary ligation, LV expansion was initially restricted and then permitted to occur. In seven sheep with LCX branch ligation, LV expansion was also initially limited but became prominent with remodeling over eight weeks. Three-dimensional echo reconstruction quantified mitral apparatus geometry and MR volume.
In the acute model, despite LV dysfunction with ejection fraction = 23 +/- 8%, MR was initially trace with limited LV dilation, but it became moderate with subsequent prominent dilation. In the chronic model, MR was also initially trace, but it became moderate over eight weeks as the LV dilated and changed shape. In both models, the only independent predictor of MR volume was increased tethering distance from the papillary muscles (PMs) to the anterior annulus, especially medial and posterior shift of the ischemic medial PM, measured by 3D reconstruction (r2 = 0.75 and 0.86, respectively). Mitral regurgitation volume did not correlate with LV ejection fraction or dP/dt.
Segmental ischemic LV contractile dysfunction without dilation, even in the PM territory, fails to produce important MR. The development of MR relates strongly to changes in the 3D geometry of the mitral apparatus, with implications for approaches to restore a more favorable configuration.
Myocardial infarction (MI) can directly cause ischemic mitral regurgitation (IMR), which has been touted as an indicator of poor prognosis in acute and early phases after MI. However, in the chronic post-MI phase, prognostic implications of IMR presence and degree are poorly defined.
We analyzed 303 patients with previous (>16 days) Q-wave MI by ECG who underwent transthoracic echocardiography: 194 with IMR quantitatively assessed in routine practice and 109 without IMR matched for baseline age (71+/-11 versus 70+/-9 years, P=0.20), sex, and ejection fraction (EF, 33+/-14% versus 34+/-11%, P=0.14). In IMR patients, regurgitant volume (RVol) and effective regurgitant orifice (ERO) area were 36+/-24 mL/beat and 21+/-12 mm(2), respectively. After 5 years, total mortality and cardiac mortality for patients with IMR (62+/-5% and 50+/-6%, respectively) were higher than for those without IMR (39+/-6% and 30+/-5%, respectively) (both P<0.001). In multivariate analysis, independently of all baseline characteristics, particularly age and EF, the adjusted relative risks of total and cardiac mortality associated with the presence of IMR (1.88, P=0.003 and 1.83, P=0.014, respectively) and quantified degree of IMR defined by RVol >/=30 mL (2.05, P=0.002 and 2.01, P=0.009) and by ERO >/=20 mm(2) (2.23, P=0.003 and 2.38, P=0.004) were high.
In the chronic phase after MI, IMR presence is associated with excess mortality independently of baseline characteristics and degree of ventricular dysfunction. The mortality risk is related directly to the degree of IMR as defined by ERO and RVol. Therefore, IMR detection and quantification provide major information for risk stratification and clinical decision making in the chronic post-MI phase.
This study was undertaken to compare mitral valve repair and replacement as treatments for ischemic mitral regurgitation.
From 1985 through 1997, a total of 482 patients with ischemic mitral regurgitation underwent either valve repair (n = 397) or valve replacement (n = 85). Patients more likely (P < or =.01) to undergo repair had functional mitral regurgitation or coronary revascularization with an internal thoracic artery graft; those more likely to receive valve replacement were in higher New York Heart Association functional classes or underwent emergency operations. These factors were used for multivariable propensity matching. Risk factors for early and late death were identified by multivariable, multiphase hazard function analysis.
Within the propensity-matched better-risk group, survivals after valve replacement were 81%, 56%, and 36% at 30 days, 1 year, and 5 years, but survivals after repair were 94%, 82%, and 58% at these intervals (P =.08). In contrast, within the poor-risk group, survivals after repair and replacement were similar (P =.4). Risk factors (P < or =.01) included older age, higher functional class, greater wall motion abnormality, and renal dysfunction. Approximately 70% of patients were predicted to benefit from repair; the benefit lessened or was negated if an internal thoracic artery graft was not used, if a lateral wall motion abnormality was present, or if the mitral regurgitation jet pattern was complex. Freedom from repair failure at 5 years was 91%.
Late survival is poor after surgery for ischemic mitral regurgitation. Most patients with ischemic mitral regurgitation benefit from mitral valve repair. In the most complex, high-risk settings, survivals after repair and replacement are similar.
This study reviews the 223 consecutive mitral valve operations for ischemic mitral insufficiency performed at New York University Medical Center between January 1976 and January 1996. The results for mitral valve reconstruction are compared with those for prosthetic mitral valve replacement.
From January 1976 to January 1996, 223 patients with ischemic mitral insufficiency underwent mitral valve reconstruction (n = 152) or prosthetic mitral valve replacement (n = 71). Coronary artery bypass grafting was performed in 89% of cases of mitral reconstruction and 80% of cases of prosthetic replacement. In the group undergoing reconstruction, 77% had valvuloplasty with a ring annuloplasty and 23% had valvuloplasty with suture annuloplasty. In the group undergoing prosthetic replacement, 82% of patients received bioprostheses and 18% received mechanical prostheses.
Follow-up was 93% complete (median 14.6 mo, range 0-219 mo). Thirty-day mortality was 10% for mitral reconstruction and 20% for prosthetic replacement. The short-term mortality was higher among patients in New York Heart Association functional class IV than among those in classes I to III (odds ratio 5.75, confidence interval 1.25-26.5) and was reduced among patients with angina relative to those without angina (odds ratio 0.26, confidence interval 0.05-1.2). The 30-day death or complication rate was similarly elevated among patients in functional class IV (odds ratio 5.53; confidence interval 1.23-25.04). Patients with mitral valve reconstruction had lower short-term complication or death rates than did patients with prosthetic valve replacement (odds ratio 0.43, confidence interval 0.20-0.90). Eighty-two percent of patients with mitral valve reconstruction had no insufficiency or only trace insufficiency during the long-term follow-up period. Five-year complication-free survivals were 64% (confidence interval 54%-74%) for patients undergoing mitral valve reconstruction and 47% (confidence interval 33%-60%) for patients undergoing prosthetic valve replacement. Results of a series of statistical analyses suggest that outcome was linked primarily to preoperative New York Heart Association functional class.
Initial mortalities were similar among patients undergoing prosthetic replacement and valve reconstruction. Poor outcome was primarily related to preexisting comorbidities. Patients undergoing valve reconstruction had fewer valve-related complications. Valve reconstruction resulted in excellent durability and freedom from complications. These findings suggest that mitral valve reconstruction should be considered for appropriate patients with ischemic mitral insufficiency.
We sought to test whether isolated mitral annular (MA) dilation can cause important functional mitral regurgitation (MR).
Mitral annular dilation has been considered a primary cause of functional MR. Patients with functional MR, however, usually have both MA dilation and left ventricular (LV) dilation and dysfunction. Lone atrial fibrillation (AF) can potentially cause isolated MA dilation, offering a unique opportunity to relate MA dilation to leaflet function.
Mid-systolic MA area, MR fraction, LV volumes and papillary muscle (PM) leaflet tethering length were compared by echocardiography among 18 control subjects, 25 patients with lone AF and 24 patients with idiopathic or ischemic cardiomyopathy (ICM).
Patients with lone AF had a normal LV size and function but MA dilation (isolated MA dialtion) significant and comparable to that of patients with ICM (MA AREA: 8.0 +/- 1.2 vs. 11.6 +/- 2.3 vs. 12.5 +/- 2.9 cm(2) [control vs. lone AF vs. ICM]; p < 0.001 for both lone AF and ICM). However, patients with lone AF had only modest MR, compared with that of patients with ICM (MR fraction: -3 +/- 8% vs. 3 +/- 9% vs. 36 +/- 25%; p < 0.001 for patients with ICM). Multivariate analysis identified PM tethering length, not MA dilation, as an independent primary contributor to MR.
Isolated annular dilation does not usually cause moderate or severe MR. Important functional MR also depends on LV dilation and dysfunction, leading to an altered force balance on the leaflets, which impairs coaptation.
Coronary arterial disease is the major cause of congestive heart failure, but suitable animal models of postinfarction, dilated cardiomyopathy do not exist. This article describes an ovine model that develops after an anterobasal infarction.
The distribution of ovine myocardium supplied by the first two diagonal branches of the left homonymous artery were determined in 20 slaughterhouse hearts and eight live sheep using methylene blue and tetrazolium injections, respectively. Seven additional animals had the infarction and underwent serial hemodynamic, microsphere and echocardiographic studies more than 8 weeks and histologic studies at the eighth week. Infarcts represented 24.6% +/- 4.7% and 23.9% +/- 2.2% of the left ventricular mass in slaughterhouse and live hearts, respectively.
During remodeling, left ventricular end-systolic and end-diastolic volumes increased 115% and 73%, respectively, ejection fraction decreased from 41.2% +/- 6.7% to 29.1% +/- 5.7%, systolic wall thickening remote from the infarct decreased by 68%, sphericity index increased from 0.465 +/- 0.088 to 0.524 +/- 0.038, and left ventricular end-diastolic pressure increased from 1.7 +/- 1.0 to 8.2 +/- 3.5 mm Hg. Serial microsphere measurements documented normal blood flow (1.34 mL/g per minute) to all uninfarcted myocardium and 22% of normal to the infarct. Viable myocardium showed mild interstitial fibrosis.
This ovine model meets all criteria for postinfarction, dilated cardiomyopathy and has the advantages of controlling for variations in coronary arterial anatomy, collateral vascularity, and differences in the numbers, location, and severity of atherosclerotic lesions that confound human studies of the pathogenesis of this disease. This simple model contains only infarcted and fully perfused, hypocontractile myocardium produced by a moderate-sized, regional infarction.
Annuloplasty rings are used to treat ischemic mitral regurgitation (IMR), but their exact effects on 3-D geometry of the overall mitral valve complex during acute left ventricular (LV) ischemia remain unknown.
Radiopaque markers were sutured to the mitral leaflet edges, annulus, papillary muscle tips, and ventricle in three groups of sheep. One group served as control (n = 5), and the others underwent Duran (n = 6) or Physio (n = 5) ring annuloplasty. One week later, 3-D marker coordinates at end-systole were obtained before and during balloon occlusion of the circumflex artery.
In all control animals, acute LV ischemia was associated with: (i) septal-lateral separation of the leaflet edges, which was predicted by lateral displacement of the lateral annulus during septal-lateral mitral annular dilatation; (ii) apical restriction of the posterior leaflet edge, which was predicted by displacement of the lateral annulus away from the non-ischemic anterior papillary muscle; (iii) displacement of the posterior papillary muscle, which was not predictive of either septal-lateral leaflet separation or leaflet restriction; and (iv) mitral regurgitation. In the Duran group during ischemia, the posterior leaflet edge shifted posteriorly due to posterior movement of the lateral annulus, but no IMR occurred. In the Physio group during ischemia, neither the posterior leaflet edge nor the lateral annulus changed positions, and there was no IMR. In both the Duran and Physio groups, displacement of the posterior papillary muscle did not lead to IMR.
Either annuloplasty ring prevented the perturbations of mitral leaflet and annular--but not papillary muscle tip--3-D geometry during acute LV ischemia. By fixing the septal-lateral annular dimension and preventing lateral displacement of the lateral annulus, annuloplasty rings prevented systolic septal-lateral leaflet separation and posterior leaflet restriction, and no acute IMR occurred. The flexible ring allowed posterior displacement of the posterior leaflet edge and the lateral annulus, which was not observed with a semi-rigid ring.
This study was conducted to elucidate the geometric differences of the mitral apparatus in patients with significant mitral regurgitation caused by ischemic cardiomyopathy (ICM-MR) and by idiopathic dilated cardiomyopathy (DCM-MR) by use of real-time 3D echocardiography (RT3DE).
Twenty-six patients with ICM-MR caused by posterior infarction, 18 patients with DCM-MR, and 8 control subjects were studied. With the 3D software, commissure-commissure plane and 3 perpendicular anteroposterior (AP) planes were generated for imaging the medial, central, and lateral sides of the mitral valve (MV) during mid systole. In 3 AP planes, the angles between the annular plane and each leaflet (anterior, Aalpha; posterior, Palpha) were measured. In ICM-MR, Aalpha measured in the medial and central planes was significantly larger than that in the lateral plane (39+/-5 degrees, 34+/-6 degrees, and 27+/-5 degrees, respectively; P<0.01), whereas Palpha showed no significant difference in any of the 3 AP planes (61+/-7 degrees, 57+/-7 degrees, and 56+/-7 degrees, P>0.05). In DCM-MR, both Aalpha (38+/-8 degrees, 37+/-9 degrees, and 36+/-7 degrees, P>0.05) and Palpha (59+/-6 degrees, 58+/-5 degrees, and 57+/-6 degrees, P>0.05) revealed no significant differences in the 3 planes.
The pattern of MV deformation from the medial to the lateral side was asymmetrical in ICM-MR, whereas it was symmetrical in DCM-MR. RT3DE is a helpful tool for differentiating the geometry of the mitral apparatus between these 2 different types of functional mitral regurgitation.
Annuloplasty is the cornerstone of surgical mitral valve repair. A percutaneous transvenous catheter-based approach for mitral valve repair was tested by placing a novel annuloplasty device in the coronary sinus of sheep with acute ischemic mitral regurgitation. Mitral regurgitation was reduced from 3-4+ to 0-1+ in all animals (P < 0.03). The annuloplasty functioned by reducing septal-lateral mitral annular diameter (30 +/- 2.1 mm preinsertion vs. 24 +/- 1.7 mm postinsertion; P < 0.03). These preliminary experiments demonstrate that percutaneous mitral annuloplasty is feasible. Further study is necessary to demonstrate long-term safety and efficacy of this novel approach.
We plan to determine whether the cause of mitral valve regurgitation, ischemic or degenerative, affects survival after combined mitral valve repair or replacement and coronary artery bypass grafting (CABG) surgery and to assess the influence of residual mitral regurgitation on late outcome.
A retrospective study was made of 302 patients having mitral valve repair or replacement and CABG from January 1987 through December 1996. Risk factors for death, for development of New York Heart Association class III or IV congestive heart failure (CHF), and recurrent mitral valve regurgitation were identified by proportional hazards analysis.
The cause of mitral regurgitation was ischemic in 137 patients (45%) and degenerative in 165 patients (55%). Valve replacement was performed in 51 patients (17%) and valve repair in 251 patients (83%). Median follow-up was 64 months. Ten-year actuarial survival rates were 33% (95% confidence interval: 22% to 47%) in the ischemic group and 52% (95% confidence interval: 42% to 64%) in the degenerative group. Univariate predictors of death, were entered into a multivariate model. Older age, ejection fraction of 35% or less, three-vessel coronary artery disease, replacement of the mitral valve, and residual mitral regurgitation at dismissal were independent risk factors for death. The cause of mitral valve regurgitation (ischemic or degenerative) was not an independent predictor of long-term survival, class III or IV CHF, or recurrent regurgitation.
Survival after mitral valve surgery and CABG is determined by the extent of coronary disease and ventricular dysfunction and by the success of the valve procedure; etiology of mitral valve regurgitation has relatively little impact on late outcome.
Ring annuloplasty, the current treatment of choice for chronic ischemic mitral regurgitation, abolishes dynamic annular motion and immobilizes the posterior leaflet. In a model of chronic ischemic mitral regurgitation, we tested septal-lateral annular cinching aimed at maintaining normal annular and leaflet dynamics.
Twenty-five sheep had radiopaque markers placed on the mitral annulus and anterior and posterior mitral leaflets. A transannular suture was anchored to the midseptal mitral annulus and externalized through the midlateral mitral annulus. After 7 days, biplane cinefluoroscopy provided 3-dimensional marker data (baseline) prior to creating inferior myocardial infarction by snare occlusion of obtuse marginal branches. After 7 weeks, the 9 animals that developed chronic ischemic mitral regurgitation were restudied before and after septal-lateral annular cinching. Anterior and posterior mitral leaflet angular excursion and annular septal-lateral and commissure-commissure dimensions and percent shortening were computed.
Septal-lateral annular cinching reduced septal-lateral dimension (baseline: 3.0 +/- 0.2; chronic ischemic mitral regurgitation: 3.5 +/- 0.4 [P <.05 vs baseline by repeated measures analysis of variance and Dunnett's test]; septal-lateral annular cinching: 2.4 +/- 0.3 cm; maximum dimension) and eliminated chronic ischemic mitral regurgitation (baseline: 0.6 +/- 0.5; chronic ischemic mitral regurgitation: 2.3 +/- 1.0 [P <.05 vs baseline by repeated measures analysis of variance and Dunnett's test]; septal-lateral annular cinching: 0.6 +/- 0.6; mitral regurgitation grade [0 to 4+]) but did not alter dynamic annular shortening (baseline: 7 +/- 3; chronic ischemic mitral regurgitation: 10 +/- 5; septal-lateral annular cinching: 6 +/- 2, percent septal-lateral shortening) or posterior mitral leaflet excursion (baseline: 46 degrees +/- 8 degrees; chronic ischemic mitral regurgitation: 41 degrees +/- 13 degrees; septal-lateral annular cinching: 46 degrees +/- 8 degrees ).
In this model, septal-lateral annular cinching decreased chronic ischemic mitral regurgitation, reduced annular septal-lateral diameter (but not commissure-commissure diameter), and maintained normal annular and leaflet dynamics. These findings provide additional insight into the treatment of chronic ischemic mitral regurgitation.
Better understanding of the precise 3-dimensional geometric changes of the mitral valvular-ventricular complex in chronic ischemic mitral regurgitation (CIMR) is needed in order to devise better surgical repair techniques. We hypothesized that changes after inferior myocardial infarction would be different in hearts that developed CIMR compared with those that did not.
Twenty-four sheep underwent coronary snare and marker placement (annulus, papillary muscles, and anterior and posterior leaflets). After 8 days, cinefluoroscopy provided 3-dimensional marker data, and snare occlusion of obtuse marginal branches created inferior myocardial infarction, including the posterior papillary muscle. After 7 weeks, the 16 surviving animals were studied again and grouped by mitral regurgitation grade (>or= 2+, n=10 versus <or= 1+, n=6). End-systolic mitral annulus dimensions, components of papillary muscle and leaflet displacement, were calculated. After inferior myocardial infarction, total displacement of the posterior papillary muscle from the midseptal annulus ("saddle horn") was greater in CIMR(+) animals: 6.5+/-3.2 versus 3.1+/-2.7 (P=0.02), with the posterior papillary muscle moving more laterally (6.8+/-3.4 versus 2.5+/-3.5 mm, P=0.01). Increase in mitral annular septal-lateral diameter was greater in animals with CIMR (4.9+/-2.7 versus 2.3+/-2.0, P=0.02), and apical displacement of the posterior leaflet (PL) margin was also greater in the CIMR(+) group (1.7+/-1.0 versus 0.3+/-0.5, P=0.01).
The CIMR(+) group had greater septal-lateral annular dilatation, lateral posterior papillary muscle displacement, and apical PL restriction, indicating that these associated geometric alterations may be important in the pathogenesis of CIMR. Treatment of CIMR should address both annular septal-lateral dilatation and lateral displacement of the posterior papillary muscle.
Local displacement and sym-metrical deformation in ischemic mitral regurgitation: a novel comput-erized 3D echo method
- M Daimon
- G Saracino
- Y Koyama
- Qin Jx
- V Kongsaerepong
- S Fukuda
- Da Agler
- Gillinov
- Am
- Thomas
- Jd
Daimon M, Saracino G, Koyama Y, Qin JX, Kongsaerepong V, Fukuda S, Agler DA, Gillinov AM, Thomas JD. Local displacement and sym-metrical deformation in ischemic mitral regurgitation: a novel comput-erized 3D echo method. Circulation. 2004;110(suppl III):III-422.
Correspondence to Takahiro Shiota, MD, Department of Cardiovascular Medicine, Desk F15, Cleveland Clinic Foundation E-mail shiotat@ccf.org ©
- Viacor
- Inc
- Wilmington
- S J B Mass
and Viacor, Inc, Wilmington, Mass (S.J.B.). Correspondence to Takahiro Shiota, MD, Department of Cardiovascular Medicine, Desk F15, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195. E-mail shiotat@ccf.org © 2005 American Heart Association, Inc. Circulation is available at http://www.circulationaha.org DOI: 10.1161/01.CIR.0000163547.03188.AC References
Local displacement and symmetrical deformation in ischemic mitral regurgitation: a novel computerized 3D echo method
- M Daimon
- G Saracino
- Y Koyama
- J X Qin
- V Kongsaerepong
- S Fukuda
- D A Agler
- A M Gillinov
- J D Thomas
Daimon M, Saracino G, Koyama Y, Qin JX, Kongsaerepong V, Fukuda
S, Agler DA, Gillinov AM, Thomas JD. Local displacement and symmetrical deformation in ischemic mitral regurgitation: a novel computerized 3D echo method. Circulation. 2004;110(suppl III):III-422.
Abstract.