Native T1 values in discrimination of subclinical profibrotic phenotype in relatives of patients with hypertrophic cardiomyopathy

Abstract

Background Hypertrophic cardiomyopathy (HCM) is associated with significant associated morbidity and mortality. Increased maximal left ventricular wall thickness (LVWT) has been postulated as major risk factor of sudden death; however, relatives with normal LVWT are also at risk. Genetically driven interstitial collagenesis has been proposed as a possible mechanism of diffuse myocardial fibrosis and increased extracellular volume fractions (ECV) has been demonstrated in genotype positive subjects. We investigated whether native T1 can also separate genotype positive subjects in the absence of increase in LVWT and how does it relate to ECV measurements.

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POSTER PRESENTATION Open Access
Native T1 values in discrimination of subclinical
profibrotic phenotype in relatives of patients with
hypertrophic cardiomyopathy
Rocio Hinojar
*
, Benjamin P Goodman, Adriana Villa, Darius Dabir, Eduardo Arroyo Ucar, Thomas Jackson,
Tobias Schaeffter, Eike Nagel, Valentina Puntmann
From 17th Annual SCMR Scientific Sessions
New Orleans, LA, USA. 16-19 January 2014
Background
Hypertrophic cardiomyopathy (HCM) is associated with
significant associated morbidity and mortality. Increased
maximal left ventricular wall thickness (LVWT) has
been postulated as major risk factor of sudden death;
however, relatives with normal LVWT are also at risk.
Genetically driven interstitial collagenesis has been pro-
posed as a possible mechanism of diffuse myocardial
fibrosis and increased extracellular volume fractions
(ECV) has been demonstrated in genotype positive sub-
jects. We investigated whether native T1 can also sepa-
rate genotype positive subjects in the absence of
increase in LVWT and how does it relate to ECV
measurements.
Methods
Seventeen genotype positive first-degree relatives of
HCM patients, and seventeen healthy volunteers under-
went assessment of T1 mapping, function and scar by
CMR at 3-Tesla scanner. T1 values were measured con-
servatively within the septal myocardium in a midventri-
cular short-axis slice prior to and 15-20 minutes after
administration of 0.2 mmol/kg of gadobutrol.
Results
Relatives of HCM patients were well matched for age,
gender and traditional cardiovascular risk factors. The
groups did not differ in the conventional LV parameters,
including volumes, left and right ejection fraction or LV
mass. None of the studied subjects showed late gadoli-
nium enhancement. Compared to controls, T1native
values were increased in HCM relatives (control vs.
relatives, T1native (msec) 1045 ± 17 vs. 1104 ± 16, p <
0.0001), whereas T1postcontrast and lambda did not
vary between groups. T1nativewasidentifiedasthe
independent discriminator to differentiate between rela-
tives of HCM patients and controls.
Conclusions
We demonstrate that T1native values are increased in
genotype positive relatives of HCM patients. We pro-
pose that T1 native may serve as an early marker of car-
diomyopathy, adding valuable information to genetic
testing in this increasing population, possibly without a
need for a contrast CMR study.
Cardiovascular Imaging Department, King’s College London, London, UK
Figure 1 ROC curves. Diagnostic Performance of T1 derived
indices (T1native, T1postcontrast, lambda) by T1 Mapping in the
detection of genotype positive first-degree relatives of HCM
patients.
Hinojar et al.Journal of Cardiovascular Magnetic
Resonance 2014, 16(Suppl 1):P241
http://www.jcmr-online.com/content/16/S1/P241
© 2014 Hinojar et al.; licensee B ioMed Central Ltd. This is an Open Access article distributed under the terms of the Crea tive Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unr estricted use, distribution, and reproduction in
any medium, pro vided the original work is properly cited. The Creativ e Commons Public Domain Dedication waiver (http://
creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stat ed.

Funding
We would like to acknowledge Department of Health
via the National Institute for Health Research (NIHR)
comprehensive Biomedical Research Centre award to
Guy’s&StThomas’NHS Foundation Trust in partner-
ship with King’s College London and King’s College
Hospital National Health Service Foundation Trust.
Dr. Rocio Hinojar was supported by the Fundacion
Alfonso Martin Escudero.
Published: 16 January 2014
doi:10.1186/1532-429X-16-S1-P241
Cite this article as: Hinojar et al.: Native T1 values in discrimination of
subclinical profibrotic phenotype in relatives of patients with
hypertrophic cardiomyopathy. Journal of Cardiovascular Magnetic
Resonance 2014 16(Suppl 1):P241.
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Hinojar et al.Journal of Cardiovascular Magnetic
Resonance 2014, 16(Suppl 1):P241
http://www.jcmr-online.com/content/16/S1/P241
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