Less Invasive Mitral Surgery Versus Conventional Sternotomy Stratified by Mitral Pathology

BACKGROUND: Our objective was to compare national mitral repair rates and outcomes after less invasive mitral surgery (LIMS) vs conventional sternotomy across the spectrum of mitral pathologies and repair techniques.

METHODS: Patients undergoing isolated primary mitral valve surgery in The Society of Thoracic Surgeons Adult Cardiac Surgery Database from July 2014 to December 2018 were evaluated. Propensity score models were constructed nonparsimoniously, and prediction models used to compute adjusted effects of surgical approach. Hypothesis tests were adjusted for propensity score with inverse-probability weighting.

RESULTS: A total of 41,082 patients met inclusion criteria; comprising 10,238 (24.9%) LIMS and 30,844 (75.1%) conventional sternotomy, with increased LIMS adoption annually. Surgeons reporting LIMS cases had higher annual median mitral case volumes than those who did not (23 vs 8, P < .001). Groups were well-balanced after propensity adjustment including mitral pathology. Propensity score-adjusted outcomes showed increased procedural volume (odds ratio 1.030 [95% confidence interval: 1.028-1.031]) and LIMS (odds ratio 2.139 [95% confidence interval 2.032-2.251]) were independently associated with higher mitral repair rates. Propensity-adjusted outcomes included reduced stroke (P < .001), atrial fibrillation (P < .001), pacemaker (P < .001), renal failure (P < .001), and length of stay (P < .001) for LIMS vs sternotomy, without differences in mortality. Operative volume influenced outcomes in both groups.

CONCLUSIONS: LIMS was associated with higher mitral repair rates, and lower morbidity. Further studies regarding the impact of surgeon volume on choice of operative approach are necessary.