Thoracoscopic trans-mitral myectomy for hypertrophic obstructive cardiomyopathy: a retrospective single-centre study

OBJECTIVES: Transaortic myectomy is a common procedure for patients with hypertrophic obstructive cardiomyopathy. Thoracoscopic trans-mitral myectomy has been described in a few small-sample studies and has been recommended as preferable. We herein report our clinical outcomes using the thoracoscopic trans-mitral approach with 76 patients. METHODS: This is a retrospective single-centre analysis of the safety and efficacy of thoracoscopic trans-mitral myectomy by comparing the clinical outcomes with that of transaortic myectomy. RESULTS: Between April 2019 and October 2021, 132 patients underwent either a transaortic (n = 56) or a thoracoscopic trans-mitral myectomy (n = 76). Compared with those in the transaortic group, patients in the trans-mitral group were more likely to be weaned off the ventilator within 24 h after surgery (80.3% vs 60.7%, P < 0.05) and to require a shorter duration of ventilation [29.01 (43.91) vs 51.12 (94.96) h, P = 0.08] and lower transfusion rate (26.3% vs 48.2%, P < 0.05). The in-hospital mortality rate of the transaortic and trans-mitral groups was 3.6% (n = 2) and 1.3% (n = 1), respectively. No significant inter-group differences were observed regarding in-hospital mortality, the incidence of low cardiac output syndrome or permanent pacemaker implantations. In the trans-mitral group, the thickness of the interventricular septum was significantly reduced postoperatively, with resultant relief of the left ventricular outflow tract obstruction [89.37 (27.5) vs 10.51 (0.65) mmHg, P < 0.01]. Transaortic myectomy also resulted in a significant reduction in left ventricular outflow tract gradient [90.41 (33.31) vs 11.35 (9.43) mmHg, P < 0.01]. And the incidence of residual systolic anterior motion of the trans-mitral group and the transaortic group was 2.67% and 1.9%, respectively. CONCLUSIONS: The thoracoscopic trans-mitral approach provides excellent exposure to the septum and anomalies of the mitral valve and papillary muscle. It relieves obstruction effectively, without increasing the incidence of major complications.

Automated summary

In this study, the clinical outcomes of thoracoscopic trans-mitral myectomy were compared with transaortic myectomy in patients with hypertrophic obstructive cardiomyopathy. The results showed that patients in the trans-mitral group had a higher rate of early extubation, shorter ventilation duration, and lower transfusion rate compared to the transaortic group. There were no significant differences in in-hospital mortality, low cardiac output syndrome, or permanent pacemaker implantations between the two groups. Thoracoscopic trans-mitral myectomy effectively relieved left ventricular outflow tract obstruction without increasing major complications.