Sex-specific differences and postoperative outcomes of minimally invasive and sternotomy valve surgery

Objectives: Female sex is an established risk factor for postoperative complications after heart surgery, but the influence of sex on outcomes after minimally invasive cardiac surgery (MICS) for valvular replacement/repair remains controversial. We examined whether the role of sex as a risk factor varies by surgical approach [MICS vs conventional sternotomy (ST)] and further assessed outcomes among female patients including in-hospital mortality and postoperative complications by surgical approach. Methods: We analysed data from a multicentre registry for patients who underwent isolated aortic valve and mitral surgery with MICS or ST. The primary outcome was in-hospital mortality. Propensity score matching was used to minimize between-group differences. Results: Among the 15 155 patients included in the study, 7674 underwent MICS (50.6%). Female sex was equally distributed in the MICS and ST groups (47.3% vs 47.6%, respectively). Risk for surgery was higher in the ST group than in the MICS group {EuroSCORE II: 4.0 [standard deviation (SD): 6.8] vs 3.7 [SD: 6.4]; P = 0.005}, including among female patients only [ST vs MICS 4.6 (SD: 6.9) vs 4.2 (SD: 6.3); P = 0.04]. Mortality did not significantly vary by procedure among women [MICS vs ST, 2.4% vs 2.8%; hazard ratio 1.09, 95% confidence interval 0.71-1.73; P (surgical approach × sex) = 0.51]. The results also did not vary after adjusting for confounders. Conclusions: Female sex was associated with higher mortality in patients undergoing valve surgery, regardless of surgical approach. In female patients, MICS did not provide any benefits over ST in terms of in-hospital deaths or postoperative complications. Subject collection: 117, 125.