Early Septal Reduction Therapy for Patients with Obstructive Hypertrophic Cardiomyopathy

Abstract Objective This study was conducted to determine the impact of early septal reduction therapy (SRT) after referral on survival in patients with obstructive hypertrophic cardiomyopathy (HCM). Methods We reviewed the patients with obstructive HCM ( resting pressure gradient ≥30 mmHg or provoked pressure gradient ≥50 mmHg) who were evaluated at our clinic from 2000 to 2012. Early SRT was defined as undergoing septal myectomy or alcohol septal ablation during the six months after index evaluation. Survival after the six-month landmark period was analyzed in a multivariable Cox model. Results A total of 1,351 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.years, the survival was comparable (p=0.207) but patients undergoing early SRT had on average improved survival compared to medical treatment group (HR 0.66, 95% CI: 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 (HR 0.51, 95% CI: 0.35 - 0.75), those who are in NYHA functional class III-IV (HR 0.52, 95% CI: 0.36 - 0.76), and non-diabetics (HR 0.59, 95% CI: 0.42 – 0.82). Conclusions In experienced HCM centers, early SRT is similar to continued medical treatment for patients with obstructive HCM. Importantly, it appears to improve survival of female patients and those who are in NYHA functional class III-IV.