Current effectiveness and risks of isolated septal myectomy for hypertrophic obstructive cardiomyopathy

Background. Septal myectomy is the gold-standard therapy for hypertrophic obstructive cardiomyopathy (HOCM). However, it is being challenged by a less-invasive alternative: alcohol septal ablation. This study examined the clinical effectiveness and risks of isolated septal myectomy for HOCM. Methods. From January 1994 to January 2005, 323 patients underwent isolated septal myectomy (mean age 50 +/- 14 years, 53% male). Preoperative septal thickness was 2.3 +/- 0.46 cm and peak left ventricular outflow tract (LVOT) gradient 68 +/- 43 mm Hg. Effectiveness of myectomy was assessed by echocardiography, sudden death, and functional limitation, early risks by intraoperative and postoperative complications, and late risks by follow-up for HOMC-related reoperation, heart block, and all-cause mortality (mean 3.6 +/- 2.8 years, 1,152 patient-years, 10% followed >= 8 years). Results. Myectomy was effective, resulting in sustained decrease in septal thickness and LVOT gradient, absence of sudden death, and improved functional status. Early in-hospital morbidity was low, with no hospital deaths; two iatrogenic ventricular septal defects were repaired uneventfully, and 22 pacemakers were required for heart block. In the intermediate term, 10 patients required HOCM-related reoperations (4 redo myectomies, 6 mitral valve procedures), with 92% freedom from reoperation at eight years. Seventy-nine percent were free of pacemakers by 8 years, and survival was 90%, equivalent to that of the general population. Conclusions. Isolated septal myectomy is effective in eliminating LVOT obstruction and sudden death and in improving functional status, with low operative morbidity and mortality. Few reoperations are required late and outcomes are excellent. It should be considered the treatment of choice for HOCM.