Surgical myectomy for hypertrophic cardiomyopathy: procedural volume and outcomes

Outcomes after surgical myectomy in hypertrophic obstructive cardiomyopathy (HOCM) patients have not been investigated in a multicentre registry with detailed clinical data. Hence, the objectives of this multicentre Dutch study are to describe the 30-day clinical outcomes after surgical myectomy, and to assess factors associated with increased 30-day complication rates.

All HOCM patients (n = 335) who underwent surgery between 2012 and 2020 across 12 Dutch hospitals were analysed using data from the Netherlands Heart Registration. Multiple logistic regression analyses assessed factors associated with a higher 30-day complication rate.

Isolated surgical myectomy was performed in 22%, surgical myectomy with one concomitant procedure in 54%, and surgical myectomy with two or more concomitant procedures in 24%. Thirty-day complication rates concerned mortality (5%), ventricular septal defect (2%), stroke (3%), and surgical reoperation (2%). Mean resting left ventricular outflow tract (LVOT) gradient improved from 61 ± 30 mmHg to 13 ± 12 mmHg postoperatively, systolic anterior motion from 80% to 8%, and mitral regurgitation grade 3 or 4 from 31% to 6%. Low-volume hospital (<10 surgical myectomy procedures/year), female sex, and ≥2 concomitant procedures were significantly associated with increased 30-day complication rates. The adjusted 30-day complication rate was increased in low-volume hospitals (odds ratio 3.23 (95% confidence interval: 1.43-8.09); P = .007).

Surgical myectomy with or without concomitant procedures effectively relieved LVOT obstruction in 93% of patients in this multicentre cohort. Female sex, ≥ 2 concomitant procedures, and low-volume hospitals were associated with higher 30-day complication rates. Although an inverse volume-complication relation was observed, this finding should be interpreted cautiously, and further investigation in larger sample size studies is warranted.