Effect of minimally invasive mitral valve surgery compared to sternotomy on short- and long-term outcomes: a retrospective multicentre interventional cohort study based on Netherlands Heart Registration

OBJECTIVES: Minimally invasive mitral valve surgery (MIMVS) has been performed increasingly for the past 2 decades; however, large comparative studies on short- and long-term outcomes have been lacking. This study aims to compare short- and long-term outcomes of patients undergoing MIMVS versus median sternotomy (MST) based on real-world data, extracted from the Netherlands Heart Registration. METHODS: Patients undergoing mitral valve surgery, with or without tricuspid valve, atrial septal closure and/or rhythm surgery between 2013 and 2018 were included. Primary outcomes were short-term morbidity and mortality and long-term survival. Propensity score matching analyses were performed. RESULTS: In total, 2501 patients were included, 1776 were operated through MST and 725 using an MIMVS approach. After propensity matching, no significant differences in baseline characteristics persisted. There were no between-group differences in 30-day mortality (1.1% vs 0.7%, P = 0.58), 1-year mortality (2.6% vs 2.1%, P = 0.60) or perioperative stroke rate (1.1% vs 0.6%, P = 0.25) between MST and MIMVS, respectively. An increased rate of postoperative arrhythmia was observed in the MST group (31.3% vs 22.4%, P < 0.001). A higher repair rate was found in the MST group (80.9% vs 76.3%, P = 0.04). No difference in 5-year survival was found between the matched groups (95.0% vs 94.3%, P = 0.49). Freedom from mitral reintervention was 97.9% for MST and 96.8% in the MIMVS group (P = 0.01), without a difference in reintervention-free survival (P = 0.30). CONCLUSIONS: The MIMVS approach is as safe as the sternotomy approach for the surgical treatment of mitral valve disease. However, it comes at a cost of a reduced repair rate and more reinterventions in the long term, in the real-world.