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![Fig. 5 The internal channels of the multi-lumen device, from [10]](profile/John-Abraham-9/publication/268795315/figure/fig9/AS:668700021645322@1536441917942/The-internal-channels-of-the-multi-lumen-device-from-10_Q320.jpg)
Infusion catheters, when used in combination with balloons, are subjected to pressure created by inflation of the balloon. The compression can reduce the catheter flow area and cause elevated shear stresses in the fluid. A model and experiments were developed with a range of applied balloon pressures to investigate whether such situations may cause...
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... first design to be analyzed by simulation is the representative single-lumen over the wire balloon angioplasty catheter, which is illustrated in Fig. 2. The figure shows a close-up view of a small section of the catheter, in the region near the inflation balloon. In this image, medication or cells travel from left to right. The inner lumen for cell or medication passage is shown as a straight channel with circular cross section. How- ever, if the balloon is inflated, it is possible to have a local reduction of the passageway and a concurrent increase in fluid stress. Figure 3 shows an image of central lumen collapse. The photograph was taken for balloon inflation pressures of 10 atm. The finding of Fig. 3 is reinforced by a flow study which showed a significant reduction in flow through a single- lumen catheter when balloon pressures exceeded approximately 6 atm. Details of the flow study showed a complete cessation of flow for elevated balloon pressures. An experiment was performed in the laboratory with se- quentially increased balloon pressures applied to the single- lumen catheter. During the experiments, high-precision pin gauges were used to measure the open lumen size. It was found that the single-lumen diameter decreased very slightly (and linearly) as the pressure increased from 0 to 6 atm. Then, a more rapid decrease occurred as balloon pressures further increased to 10 atm. At that pressure, there was no measurable open area in the single-lumen catheter; at this pressure, the balloon was nearly fully occluded. Confirming experiments that measured fluid flow showed that balloon pressures in excess of 10 atm resulted in very little flow through the inner lumen. Figure 4 shows the change in catheter open diameter with pressure, individual measurements are shown by the data ...
Citations
... Similarly, who could imagine small machines that break blood clots and increase life expectancy? Nanotechnology is also being used to deliver therapeutics to targeted locations within the human body [5][6][7][8][9]. ...
The advent of nanotechnology is an advancement that represents a fundamental change that will lead to the development of materials and tools in the future. The possibility of using nano-building blocks in size and composition is revolutionizing material science. Currently there are many ongoing studies of nanotechnology, its applications, benefits, and future prospects. In the marine industry, which includes a wide range of industries such as shipbuilding, submarines, and offshore platforms, nanotechnology is providing many uses. In fact, nanotechnology has valuable applications in various sectors of the marine industry where it can revolutionize the marine industry. Studies have shown that nanoparticles added to fuel can reduce fuel consumption in diesel engines and can reduce pollutants. The addition of these nanoparticles to the fuel leads to the decomposition of burnt hydrocarbons and soot, which improves efficiency. Consequently, the amount of soot, HC and CO decreases. The results of physical testing have confirmed the role of nanoparticles for increasing efficiency and reducing pollution. In this study, some applications of nanotechnology in the marine industry are discussed. For example, nanoparticle matrices in battery electrodes can drastically increase their ability to store lithium ions, increasing the storage density of the battery. Graphene can be used as a self-lubricating solid or as an additive for lubricating oils. Application of nanotechnology for the fabrication of cellular ceramic can improve its thermal stability and mechanical strength. Overall, nanotechnologies seem to have huge potential in areas as diverse as drug development, water decontamination, information and communication infrastructures, and the production of stronger, lighter and perfect nanomaterials. The benefits of nanotechnology to marine applications is no less significant.
... We did not consider the effects of the drill bit angle and geometry on the thermal necrosis of the artery wall vascular nerves during the DCP process. In previous studies, thermal stress has been investigated in a rotational atherectomy process, however, it is suggested that future studies should investigate mechanical impact on the blood (hemolysis) during this process [38]. ...
Objective: Drilling of calcifed plaque (DCP) inside the artery is a method for removing calcifed plaques. This study
investigated the efect of drill. To validate the maximum temperature calculated by computer simulation, this value
was also measured by an experimental on a phantom model.
Results: Increasing drill bit diameter during drilling would increase the temperature in vascular nerves. In a drill bit
with a diameter of 4 mm, the risk of thermal necrosis in vascular nerves of the artery wall decreased by 8.57% by
changing the drill from WC to NT. The same value for a drill bit with a diameter of 6 mm was 10.17%. However, the
trend of the generated temperature in the vascular nerves did not change signifcantly with change of the material
and diameter of the drill bit. The results showed that for DCP with the least risk of thermal necrosis in vascular nerves
and subsequently the lowest risk of restenosis, coagulation and thermal stroke of the patient, the best option is to use
a drill bit with a diameter of 4 mm and NT material for drilling.
... According to the literature, it can be understood that there are many attempts to investigate the efficiency of IABP and generally LVAD in the view aspects of manufacturing, biocompatibility and hemodynamic through modeling and simulation. It needs to mention that hemolysis [14,15] is a crucial factor which definitely must be taken into account when a company fabricates an assist device. Cardiac assist devices may damage red blood cells (RBC) when they are working and this should be considered while implanting in the patient's heart. ...
AVICENA is a new cardiac assist device which helps the patients suffering from left ventricular failure. This study aims to investigate the performance of this device and its effect on the aortic valve within different patterns of inflation and deflation of the balloon. Twelve different displacement factor curves which are applied to the balloon part of AVICENA and required for the performing of balloon inflation and deflation are selected and examined in three cases named low-pressure, normal-pressure, and high-pressure subjects. The results of generated energy, aortic valve force and pressure required for the balloon’s inflation and deflation are presented within a heart cycle. The outcomes of the present study can be utilized in designing of the AVICENA with more power generation and less aortic valve force for different subjects.
... There, an illustration of the multi-lumen catheter is provided. This catheter is termed the ND ® Infusion Catheter which was also subject to prior published research [36][37][38]. ...
p>A new device has been designed, developed and tested to improve the capacity of vascular drug and stem cell delivery. The device consists of a catheter with a multitude of small lumens (instead of a large central channel lumen). The use of multiple lumens provides a number of benefi ts to medical intervention. First, the multiple lumens are spread across the catheter cross section. As a consequence, the medication/stem cells are more effectively dispersed into the artery. Second, the construction of the new catheter has an increased mechanical strength compared to the standard single-lumen catheter – therefore, it is able to resist compressive forces caused by a pressurized balloon. This fact makes the new design able to preserve medication/stem cell flowrates without causing mechanical hemolysis to the cells. Finally, the newly designed device prohibits clumping of stem cells carried in solution.</p
... Regardless, cell retention remains very low within the heart, and hence, additional research for alternative devices is necessary. Dib et al. [90] investigated the effect of balloon inflation on the viability of the infused cells, and suggested that multi-lumen catheters are superior. Behfar et al. [91] modelled alternative needle designs to the conventional straight or helical needles with an end-hole. ...
When stressed by ageing or disease, the adult human heart is unable to regenerate, leading to scarring and hypertrophy and eventually heart failure. As a result, stem cell therapy has been proposed as an ultimate therapeutic strategy, as stem cells could limit adverse remodelling and give rise to new cardiomyocytes and vasculature. Unfortunately, the results from clinical trials to date have been largely disappointing. In this review, we discuss the current status of the field and describe various limitations and how future work may attempt to resolve these to make way to successful clinical translation.
Infusion catheters, when used with balloons, are susceptible to compression of the catheter lumen. A consequence is that shear stress is increased in the fluid that passes through the lumen. When the injected fluid contains viable cells, hemolysis of the cells can result. This study investigates the effect of a new injection catheter design which is intended to resist the deleterious effect of balloon compression on cell viability for various flowrates, balloon pressures, and fluid viscosity values. Two types of catheters were employed for the study; a standard single-lumen device and a newly designed multi-lumen alternate. Experimental and numerical simulations show that for a single-lumen injection catheter, balloon pressures in excess of 7–8 atm have the potential for causing hemolysis for flows of approximately 1–4 ml/min. The critical balloon pressure is dependent on the viscosity of the cell-carrying fluid and the injectant flowrate. Higher injection rates and viscosities lead to lower threshold balloon pressures. The results show a sharp rise in cell death when pressures rose above approximately 7 atm. On the other hand, the multi-lumen design was shown to resist hemolysis for all tested and simulated balloon pressures and flowrates up to 10 ml/min. Experimental results confirmed the numerical findings that hemolysis-causing shear stress was not found with the multi-lumen, up to 12 atm. This study indicates that a pressure-resistant multi-lumen catheter better preserves cell viability compared to the standard.
Hemodynamics and the interaction between the components of the cardiovascular system are complex and involve a structural/fluid flow interaction. During the cardiac cycle, changes to vas-cular pressure induce a compliant response in the vessels as they cyclically stretch and relax. The compliance influences the fluid flow throughout the system. The interaction is influenced by the disease state of the artery, and in particular, a plaque layer can reduce the compliance. In order to properly quantify the fluid-structural response, it is essential to consider whether the tissue surrounding the artery provides a support to the vessel wall. Here, a series of calculations are provided to determine what role the supporting tissue plays in the vessel wall and how much tissue must be included to properly carry out future fluid-structure calculations. Additionally, we calculate the sensitivity of the compliance to material properties such as the Young's modulus or to the transmural pressure difference.
