Does the genotype of hypertrophic cardiomyopathy impact the outcomes of septal myectomy?

Abstract

This study investigated the relationship between genetic profiles and clinical, pathologic, and surgical outcomes in patients undergoing septal myectomy for obstructive hypertrophic cardiomyopathy (oHCM). Clinical, echocardiographic, and histopathologic data were compared across 3 groups: variant-positive (VP), variant of undetermined significance (VUS), and variant-negative (VN). Genetic testing was conducted in 533 patients undergoing transaortic septal myectomy for oHCM between 2000 and 2022; 153 patients were classified as VP, 73 as VUS, and 307 as VN. Patients in VP and VUS groups were generally younger (mean age 46 [VP] vs 46 [VUS] vs 56 [VN], P < .001) and had fewer comorbidities but had greater prevalences of ICDs at baseline (29 vs 21 vs 9%, P < .001), compared with those in the VN group. The VP and VUS groups more frequently exhibited asymmetrical septal hypertrophy (70 vs 63 vs 53%, P < .001) with slightly more prominent hypertrophy (22 vs 22 vs 20 mm, P < .001) compared to the VN group. Histologically, severe myocardial hypertrophy and interstitial fibrosis were most common in the VP group, followed by VUS, whereas endocardial thickening was more prominent in the VN group. The predischarge median maximal gradient and the long-term survival were similar among all groups. No individual gene mutation significantly affected survival. In this study of patients with oHCM who underwent septal myectomy and genetic testing, septal myectomy provided effective relief of obstruction and comparable long-term survival across genetic groups.