Aortic Stiffness in Youth with Hypertrophic Cardiomyopathy Genotype.

Clinical events in hypertrophic cardiomyopathy (HCM) patients are related to the degree of hypertrophy. Aortic stiffness in adult HCM patients has been reported to be higher than control patients. Increased stiffness may cause more LV hypertrophy and thus lead to more clinical events. We sought to (a) noninvasively compare aortic structure and function between youth with sarcomeric HCM genotype versus control youth and (b) explore the relation between aortic function and degree of left ventricular (LV) hypertrophy. In a prospective study from a single referral center, clinical, anthropometric, and hemodynamic data were acquired on 28 consecutive pathogenic HCM gene mutation carriers and 26 unrelated controls (mean age 16.3, 50 % girls). Hemodynamic data included applanation tonometry measured central pulse pressure, carotid-femoral pulse wave velocity (CFPWV), reflected wave augmentation index (AIx). In the HCM gene carriers, LV mass-to-volume ratio was extracted from clinically indicated echocardiograms as an index of hypertrophy. Associations were assessed using multivariable adjusted linear regression. The HCM group was comprised of 14 myosin binding protein C3 carriers, 13 myosin heavy chain 7 carriers, and 1 child with both. HCM and control groups did not differ by age, sex, height, body mass index, heart rate, or blood pressure. HCM carriers had significantly lower CFPWV than controls (4.46 ± 0.88 vs. 4.97 ± 0.44 m/s, p = 0.01) and higher AIx magnitude (27 ± 19 vs. 18 ± 7 %, p = 0.04). These associations persisted after adjustment for age, sex, height, heart rate, mean pressure, and medication use. Within the HCM group, LV hypertrophy was related to AIx but not CFPWV. CFPWV nor AIx differed by genotype. Aortic stiffness appears lower, but wave reflection appears higher in youth carrying HCM gene mutations. The degree of wave reflection appears correlated with LV hypertrophy in this high-risk cohort, suggesting that mitigation of wave reflection may possibly attenuate LV hypertrophy.