Background:
In hypertrophic cardiomyopathy (HCM) with severe left ventricular outflow tract obstruction (LVOTO), surgical myectomy (SM) performed for relief of intractable symptoms is safe and associated with excellent long-term symptom-free survival. In such patients, we sought to determine if SM also results in improvement of long-term outcomes.
Methods:
We studied 1530 HCM patients with severe LVOTO (50±13 years, 63% men) that were evaluated at our center [excluding <18 years of age, LV ejection fraction (LVEF) <50%, LVOT gradient <30 mm Hg). Clinical, echocardiographic and surgical data were recorded. A composite endpoint of death and/or implantable defibrillator (ICD) discharge was recorded.
Results:
Hypertension, coronary artery disease (CAD), family history of HCM and syncope were present in 41%, 15%, 17% and 18%, while 73% patients were in Functional Class (FC) ≥ II. Mean LVEF, basal septal thickness, LVOT gradient (resting or provocable) and indexed left atrial dimensions were 62±5%, 2.2±1 cm, 101±39 mm Hg, 2.2±0.4 cm/m2. During 8±6 years of follow-up, 990 (65%) patients underwent SM (of which 65% were isolated SM), while 540 (35%) did not. 94 (6%) patients had alcohol septal ablation (66 in the non myectomy group), while 18% developed atrial fibrillation (AF), and 18% had ICD. There were 169 (11%) events (151 deaths), with 0% 30-day mortality in the SM group. On stepwise multivariable Cox Proportional Hazard analysis, increasing age (Hazard Ratio or HR 1.22 [1.06-1.40]), CAD (HR 1.57 [1.06-2.33]), worsening FC (HR 1.34 [1.05-1.71]) and AF (HR 1.73 [1.23-2.43]) predicted higher events, while SM as a time-dependent covariate (HR 0.58 [0.41-0.81]) was associated with improved event-free survival (all p<0.01). Kaplan-Meier curve showing impact of SM on outcomes is shown in Figure.
Conclusion:
In HCM patients with severe LVOTO, SM is associated with significant improvement in long-term outcomes when compared to watchful waiting.
Does relief of outflow tract obstruction in patients with hypertrophic cardiomyopathy improve long-term survival? Implications for lowering the threshold for surgical myectomy and alcohol septal ablation
