Left Ventricular Outflow Tract Modification During Robotic Mitral Valve Repair.

Abstract

Background: Earlier intervention for mitral valve (MV) regurgitation leads to smaller left ventricles (LV) and potentially increases the risk of post-operative systolic anterior motion (SAM). We performed left ventricular outflow tract (LVOT) modification in patients with an increased risk of SAM.

Methods: From January 2019 to May 2024, 800 consecutive totally endoscopic robotic MV repairs (TERMVR) were performed. Based on pre-bypass TEE, post-operative SAM risk was graded as low(n=610,76.2%), moderate(n=144, 18%), or high(n=46, 5.8%). Patients with moderate or high risk of SAM were categorized as "increased risk of SAM". To prevent post-operative SAM, LVOT modification consisted in ventricular septal bulge(VSB) myectomy and/or septal myocardial trabeculations(SMT) resection. Operative notes, echocardiograms, and STS dataset were analyzed.

Results: Mean patient age was 63.8 years (range= 22-90); 45(5.6%) had prior cardiac surgery. Thirty-day mortality was 5(0.6%). A total of 190(23.8%) patients had an increased risk of SAM. LVOT modification was performed in the majority with increased risk of SAM (139/190, 73.2%) and in a minority with low risk of SAM (42/610,6.9%). In those undergoing LVOT modification(n=181), isolated VSB myectomy was performed in 140(77.3%), isolated SMT resection in 32(17.7%), and both in 9(5.0%). The anterior leaflet was never detached. One patient experienced transient SAM while on inotropes. There was no need for intraoperative MV repair revision for SAM.

Conclusions: Currently, a significant proportion of MV repairs are at elevated risk of post-operative SAM. In our TERMVR experience, LVOT modification was performed with minimal morbidity and prevented any subsequent MV repair revision for SAM.