Survival After Myectomy for Obstructive Hypertrophic Cardiomyopathy: What Causes Late Mortality?

Background: Survival of patients with obstructive hypertrophic cardiomyopathy who undergo septal myectomy appears to be excellent and, in some series, is similar to that of matched populations. In this study, we investigated causes of late death in a large cohort of surgical patients. Methods: Between January 1961 and October 2017, 2,956 patients underwent surgery for hypertrophic cardiomyopathy. We reviewed medical records of these patients. Vital status and causes of mortality were verified using 2 methods: LexisNexis Accurint, a commercially available resource, and the National Death Index, a government database. Results: The median age was 56 (interquartile range, 44 to 65) years, and 1,624 (55%) were men. Genetic testing was performed in 416, and 97 (23%) had a positive genetic test. After operation, 1-year, 10-year, and 20-year survival estimates were 98%, 85%, and 52%, respectively. Mortality occurred in 460 (16%) patients, and cause of death could be obtained in 398 (87%). Cardiac-related deaths occurred in 224 (56%), with hypertrophic cardiomyopathy the primary cause of death in 64. Other cardiac causes of mortality included coronary artery disease (n = 64), stroke (n = 23), other cardiomyopathy (n = 20), and heart failure (n = 15). Noncardiac deaths occurred in 174 (44%). Gene-positive status was not associated with overall mortality. Conclusions: This study, using 2 independent sources to verify vital status and cause of mortality, confirms that survival after septal myectomy is excellent. Hypertrophic cardiomyopathy was identified as the primary cause of death in less than 20%, with mortality in most patients unrelated to hypertrophic cardiomyopathy.