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.