Early septal reduction therapy for patients with obstructive hypertrophic cardiomyopathy

Objective: This study was conducted to determine the influence of early septal reduction therapy (SRT) after referral on survival in patients with obstructive hypertrophic cardiomyopathy.

Methods: We reviewed the patients with obstructive hypertrophic cardiomyopathy (resting pressure gradient ≥30 mm Hg or provoked pressure gradient ≥50 mm Hg) who were evaluated at our clinic from 2000 to 2012. Early SRT was defined as undergoing septal myectomy or alcohol septal ablation during the 6 months after index evaluation. Survival after the 6-month landmark period was analyzed in a multivariable Cox model.

Results: A total of 1351 patients were included in the landmark analysis. Patients who were more symptomatic and had received more medical treatment at index evaluation were more likely to undergo early SRT. Over a median follow-up period of 10.2 years, the survival was comparable (P = .207) but patients undergoing early SRT had, on average, improved survival compared with the medical treatment group (hazard ratio, 0.66; 95% confidence interval, 0.48-0.90) after adjustment by age and comorbidities. Further analysis revealed significant treatment heterogeneity, with increased benefit of early SRT seen in women (hazard ratio, 0.51; 95% confidence interval, 0.35-0.75), those who are in New York Heart Association functional class III or IV (hazard ratio, 0.52; 95% confidence interval, 0.36-0.76), and patients without diabetes (hazard ratio, 0.59; 95% confidence interval, 0.42-0.82).

Conclusions: In experienced hypertrophic cardiomyopathy centers, early SRT is similar to continued medical treatment for patients with obstructive hypertrophic cardiomyopathy. It appears to improve survival of female patients and those who are in New York Heart Association functional class III or IV.