Clinical and echocardiographic determinants of long-term survival after surgical myectomy in obstructive hypertrophic cardiomyopathy

Background - Surgical myectomy has been the standard treatment for patients with drug-refractory obstructive hypertrophic cardiomyopathy. The clinical and echocardiographic predictors of long-term survival and freedom from cardiovascular morbidity after myectomy have been unclear. Methods and Results - We studied a consecutive cohort of 338 adult patients ( age at operation 47 +/- 14 [ range 18 to 77] years, 60% male) who underwent myectomy at our institution. Preoperative resting left ventricular outflow tract (LVOT) gradient was 66 +/- 32 mm Hg ( range 5 to 158 mm Hg). Early postoperative mortality was 1.5% ( 5 deaths): 4 deaths occurred between 1978 and 1992, and 1 death occurred between 1993 and 2002. During long-term follow-up, 83% of patients reported an improvement to functional class I or II. The majority of patients (98%) had no resting LVOT gradient. Long-term survival was excellent, with 98 +/- 1% survival at 1 year, 95 +/- 1% at 5 years, and 83 +/- 3% at 10 years after myectomy. Multivariable Cox regression analysis identified 5 predictors of overall mortality: ( 1) age >= 50 years at surgery ( hazard ratio [HR] 2.8, 95% CI 1.5 to 5.1, P = 0.001), ( 2) female gender ( HR 2.5, 95% CI 1.5 to 4.3, P = 0.0009), ( 3) history of preoperative atrial fibrillation ( HR 2.2, 95% CI 1.2 to 4.0, P = 0.008), ( 4) concomitant CABG ( HR 3.7, 95% CI 1.7 to 8.2, P = 0.001), and ( 5) preoperative left atrial diameter >= 46 mm ( HR 2.9, 95% CI 1.6 to 5.4, P = 0.0008). Significant predictors of late major cardiovascular events found on multivariable analysis were ( 1) female gender ( HR 3.3, 95% CI 2.0 to 5.4, P < 0.0001), ( 2) history of preoperative atrial fibrillation ( HR 1.9, 95% CI 1.1 to 3.3, P = 0.02), and ( 3) preoperative left atrial diameter >= 46 mm ( HR 2.5, 95% CI 1.5 to 4.3, P = 0.0008). Conclusions - Myectomy provides excellent relief for LVOT obstruction in patients with hypertrophic cardiomyopathy. Preoperative clinical and echocardiographic variables can predict long-term outcome after myectomy.