Outcomes of Concomitant Mitral Intervention in Hypertrophic Obstructive Cardiomyopathy Surgery?: A Systematic Review and Meta-Analysis of Contemporary Evidence.

Abstract

The 2020 American Heart Association Guidelines advise not to perform mitral valve replacement (MVR) during septal myectomy (SM) to alleviate outflow obstruction. This study aims to review outcomes after concomitant mitral valve (MV) intervention versus SM alone. We conducted a comprehensive literature search across Embase, PubMed, and Scopus. Studies published up to June 15, 2024 were considered. We included studies that compared SM alone to concomitant MV repair or replacement. Subgroup analyses based on MV intervention were performed. Seven studies met our criteria, including 1 randomized and 6 observational studies. The total sample size was 17,565 patients with hypertrophic cardiomyopathy (11,849 SM, 2303 SM + MVR, and 3390 SM + MV repair). Patients who underwent SM + MV intervention had more pronounced preoperative MV regurgitation. SM + MVR was associated with significantly higher early mortality [risk ratio (RR): 2.85, 95% confidence interval (CI): 2.37-3.43, P < 0.00001, I ² = 0%]. However, there was no difference in early mortality in patients who underwent SM + MV repair compared with SM alone (RR: 1.14, 95% CI: 0.88-1.49, P = 0.33, I ² = 0%). Thirty days systolic anterior motion was significantly lower in patients who underwent SM + MV repair compared with SM alone (RR: 0.15, 95%CI: 0.05-0.45, P = 0.0007). Peak pressure left ventricular outflow tract gradient was significantly lower in the SM + MV repair group compared with SM alone (mean difference: -3.47, 95% CI: -5.55 to -1.39, P = 0.001). Current observational evidence suggests an increased risk of in-patient mortality in patients who underwent SM + MVR. SM + MV repair did not affect early mortality but was linked to improved outcomes. Future comprehensive and matched studies are warranted.