Subvalvular Left Ventricular Outflow Tract Modification During Robotic Mitral Valve Repair

D. Loulmet¹, M. Dorsey¹, X. Zhou¹, L. James¹, J. Scheinerman², K. G. Phillips¹, N. Naito³, E. Grossi^4
1NYU Langone Health, New York, New York ²NYU Langone Health, New York, Nebraska ³Shizuoka Medical Center/ Kitasato University, Shizuoka, New York ⁴New York University Medical Center, New York, New York

Purpose: As guidelines now recommend earlier intervention for mitral regurgitation(MR) prior to onset of ventricular dilation or depressed function, patients have smaller ventricular volumes and are at increased risk of systolic anterior leaflet motion(SAM) post-repair. We addressed this with aggressive left ventricular outflow tract(LVOT) modification in patients with elevated SAM risk.

Methods: A review of totally endoscopic robotic assisted mitral valve repairs (TERAMVR) (1/2019 through 5/2024) performed by an experienced two-surgeon team was conducted. Patients diagnosed with pre-operative SAM were excluded. Before cardiopulmonary bypass, the surgeons graded the post-operative risk of SAM as low (n = 610, 76.2%), moderate (n = 144, 0.18%), or high (n = 46, 0.58%) based on transesophageal echocardiography. Patients with moderate or high risk of SAM were categorized as having “increased risk of SAM” during further analysis. Surgical approaches to reduce SAM included LVOT modification through septal myomectomy or resection of obstructing muscle bundles (OMB). All patients with increased risk of SAM received ‘true-sized’ semi-rigid band posterior annuloplasty. Operative notes and pre-, intra-, and post-operative echocardiograms were coded using natural language processing and additional patient variables were obtained from the STS National database. Data was analyzed in SPSS.

Results: 800 patients underwent TERAMVR. Mean patient age was 63.8 years (range = 22 – 90); 45 (5.6%) had prior cardiac surgery. Five patients died within 30 days of procedure (0.6%). Before bypass, post-bypass risk of SAM was estimated to be increased in 190 (23.8%). LVOT modification was performed in the majority of patients with increased risk of SAM (144/190, 73.2%) and in a minority of patients at low risk of SAM (42/610, 6.9%). Of the patients undergoing LVOT modification (n = 181), isolated septal myomectomy was performed in 140 (77.3%), isolated OMB resection in 32 (17.7%), and both in 9 (5.0%). All of these procedures were done from a subvalvular approach without anterior leaflet detachment. Perioperative variables and outcomes are shown in Table 1. No patients required intraoperative repair revision for SAM; one experienced transient SAM while on inotropes prior to discharge.

Conclusion: Currently, a significant proportion of patients undergoing repair for MR are at elevated risk of SAM. In this report of 800 robotic mitral repairs, LVOT modification was performed through a subvalvular approach with minimal morbidity and no requirements for subsequent revision of the initial repair for SAM.

Identify the source of the funding for this research project: Internal Departmental Funding