Hypertrophic obstructive cardiomyopathy: comparison of outcomes after myectomy or alcohol ablation adjusted by propensity score.

Objective: In November 1998, our center began offering alcohol ablation as an alternative to surgical myectomy for patients with hypertrophic obstructive cardiomyopathy. Patients with concomitant lesions were referred for surgical intervention, and the others were offered either treatment option. We sought to review the early outcomes for both protocols.
Methods: One hundred fifty patients had intervention for hypertrophic obstructive cardiomyopathy to June 30, 2003. Sixty patients elected to have alcohol ablation, and 5 crossed over to surgical intervention. A total of 95 patients had a myectomy. Patients having an isolated myectomy (n = 48) are compared with those who had an ablation. Hospital records were reviewed, and follow-up contact (mean, 2.2 years) with the patient or referring cardiologist and recent echocardiographic reports were obtained. Differences in clinical and hemodynamic outcomes between achieved treatment groups were compared after adjustment for differing baseline patient characteristics, including use of a propensity score, to adjust for the non-randomization.
Results: The patients undergoing alcohol ablation (n = 60) were older (58 vs 48 years) and had fewer associated lesions (1 vs 39 patients), lower pressure gradients (67 vs 73 mm Hg), and similar symptomatic status and degrees of mitral regurgitation compared with those in the myectomy group. Alcohol ablation was abandoned in 6 patients, 5 of whom underwent myectomy. Among the completed alcohol ablations, there were 5 late deaths, and 1 other patient was referred for myectomy. One late death occurred after myectomy. At latest follow-up, 3-year survival is 97%, and 92% of the patients are in New York Heart Association class II or I. Adjusted comparisons showed significantly lower postintervention left ventricular outflow gradients at rest in the myectomy group (5 vs 15 mm Hg), with provocation (14 vs 42 mm Hg), mitral systolic anterior motion (67% vs 29%), and New York Heart Association class. No significant difference was present in postintervention septal thickness or freedom from postintervention pacing, although in time-related analysis, the 3-year freedom from pacing is 88% versus 59% (P = .02), favoring myectomy.
Conclusion: Either alcohol ablation or myectomy offers substantial clinical improvement for patients with hypertrophic obstructive cardiomyopathy. Hemodynamic resolution of the obstruction and its sequelae is more complete with myectomy. Residual lesions after alcohol ablation might affect longer-term outcomes.