Coexistence of hypertrophic cardiomyopathy and bicuspid aortic valve: Diagnostic challenges and clinical implications – a review of literature and our experience

Hypertrophic cardiomyopathy (HCM) is the most common monogenetic cardiomyopathy. It is characterized by cardiomyocyte hypertrophy, disarray, and interstitial fibrosis. There are well-described abnormalities of the mitral valve leaflets and sub-valvular apparatus with HCM that are not attributable to sarcomeric gene mutations. Bicuspid aortic valve (BAV) is a congenital heart condition characterized by fusion of two of the three aortic valve leaflets, occurring during embryological development. The estimated prevalence of HCM and BAV is 0.2% and 1-2%, respectively. Studies on families and individuals suggest a possible association between these conditions. We reviewed imaging studies from 399 patients within our institutional HCM registry, and found BAV in 2% (8/399) of subjects, similar to the reported prevalence in the general population. Among the 8 patients with BAV, 5 had phenotypic HCM, and 3 had a strong family history of HCM. One patient with BAV had a family history of a known HCM gene mutation, but had no phenotypic or genotypic evidence of HCM. Clinical manifestations in the patients varied widely and ranged from being asymptomatic to requiring septal reduction procedures for refractory symptoms, valve replacement and cardiac transplant. Our findings suggest that despite the associations between HCM and mitral valve abnormalities, the coexistence of HCM and BAV is likely coincidental. The coexistence of these conditions may have significant clinical implications in diagnosis and management.