Midterm results of latent outflow tract obstruction in hypertrophic cardiomyopathy after septal myectomy: A propensity score‐matched study

Abstract

Background and Aim of the Study The midterm clinical outcomes of patients with latent left ventricular outflow tract (LVOT) obstruction who undergo septal myectomy are unclear. Therefore, this study aimed to evaluate the clinical outcomes of patients with latent LVOT obstruction who underwent septal myectomy. Methods We studied 34 patients with hypertrophic cardiomyopathy (HCM) and latent LVOT obstruction who underwent septal myectomy in 2011–2019 at Anzhen Hospital. After 2:1 propensity score matching, the study cohort included 34 patients with latent LVOT obstruction and 68 patients with resting LVOT obstruction. Results Compared to patients with resting LVOT obstruction, patients with latent LVOT obstruction had a thinner interventricular septal thickness (18.2 ± 3.2 mm vs. 20.4 ± 5.6 mm; p = .01), while the proportion of moderate or severe mitral regurgitation was significantly higher (26.5% vs. 5.9%; p = .003). Moreover, the proportion of mitral valve procedures (26.5% vs. 5.9%; p = .004) was significantly higher in patients with latent LVOT obstruction. However, there was no intergroup difference in cardiovascular death (5.9% vs. 1.5%, p = .26). Furthermore, the 5‐year survival rates after sudden cardiac death (100.0% vs. 91.7%; p = .26) and cardiovascular death (95.5% vs. 89.0%; p = .32) were similar between HCM patients with latent versus resting LVOT obstruction. Conclusions Midterm clinical outcomes were similar and excellent in a matched cohort of HCM patients with latent versus resting LVOT obstruction after septal myectomy.

Transapical beating-heart septal myectomy for hypertrophic cardiomyopathy with latent obstruction

“…Although numerical differences were observed, the incidence of major adverse events was not statistically significant (6.1% vs 2.3%, P = 0.649), which included a composite of 30-day mortality, ventricular septal perforation, LV apical tear, median sternotomy conversion, iatrogenic valvular injury, instrument-related embolization or stroke. In this study, the differences in overall 30-day survival were not statistically significant (100% vs 98.9%), which was similar to previous studies [ 8 , 21 ]. Ventricular septal perforation occurred in 1 (0.8%) patient with a preoperatively maximal septal thickness of 15.2 mm and with a postoperatively minimum residual septal thickness of 5.9 mm.…”

“…Our previous study has shown that, enabled by an innovative beating-heart myectomy device (BMD), the novel minimally invasive transapical beating-heart septal myectomy (TA-BSM) procedure achieved favourable results for patients with obstructive HCM, without median sternotomy and cardiopulmonary bypass (CPB) [ 7 ]. However, several studies reported that patients with latent obstruction had a higher prevalence of mitral subvalvular abnormalities and needed concomitant mitral subvalvular management [ 8 , 9 ]. Therefore, it is unclear whether the TA-BSM procedure is also appropriate for patients with latent obstruction.…”