Left Ventricular Outflow Tract Modification During Robotic Mitral Valve Repair

Earlier intervention for mitral valve (MV) regurgitation leads to smaller left ventricles and potentially increases the risk of postoperative systolic anterior motion (SAM). This study performed left ventricular outflow tract (LVOT) modification in patients with an increased risk of SAM.

From January 2019 to May 2024, 800 consecutive, totally endoscopic robotic MV repairs (TERMVRs) were performed. On the basis of prebypass transesophageal echocardiography, postoperative SAM risk was graded as low (n = 610; 76.2%), moderate (n = 144; 18%), or high (n = 46; 5.8%). Patients with a moderate or high risk of SAM were categorized as "increased risk of SAM." To prevent postoperative SAM, LVOT modification consisted of ventricular septal bulge (VSB) myectomy or septal myocardial trabeculation (SMT) resection, or both. Operative notes, echocardiograms, and The Society of Thoracic Surgeons data set were analyzed.

Mean patient age was 63.8 years (range, 22-90 years); 45 (5.6%) patients had previous 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 of patients with an increased risk of SAM (139 of 190; 73.2%) and in a minority with a low risk of SAM (42 of 610; 6.9%). In patients undergoing LVOT modification (n = 181), isolated VSB myectomy was performed in 140 (77.3%), isolated SMT resection was performed in 32 (17.7%), and both procedures were performed in 9 (5.0%). The anterior leaflet was never detached. One patient experienced transient SAM during inotropic therapy. There was no need for intraoperative MV repair revision for SAM.

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