Ministernotomy versus conventional sternotomy for aortic valve replacement: matched propensity score analysis of 808 patients

OBJECTIVES: The proportion of minimally invasive approaches is rising in cardiac surgery, in part driven by increasing patient demand. This study aimed to perform a risk-adjusted comparison of mortality, rate of stroke and perioperative morbidity of aortic valve replacement (AVR) conducted through either partial ministernotomy or conventional sternotomy. METHODS: Between July 2009 and July 2012, data from 984 consecutive patients undergoing isolated AVR were prospectively recorded. In 44.3% (n = 436), the less invasive partial ministernotomy was used. Propensity score matching was performed based on 15 preoperative risk factors to correct for selection bias. In-hospital mortality, stroke rate as well as other major complications in the minimally invasive group and conventional sternotomy group were compared in 404 matched patient pairs (total 808). RESULTS: In-hospital mortality and rate of postoperative intra-aortic balloon pump use were identical for propensity-matched patients, 1.0% (4 in each group). The rate of stroke [OR (95% confidence interval (CI)): 0.80 (0.22–2.98)], perioperative myocardial infarction [OR (95% CI): 2.00 (0.18–22.06)], low-output syndrome [OR (95% CI): 0.90 (0.37–2.22)], new onset of dialysis [OR (95% CI): 1.25 (0.49–3.17)] and re-exploration for bleeding [OR (95% CI): 0.88 (0.50–1.56)] were similar. Likewise, resource utilization (operation time, duration of stay in the intensive care unit and in-hospital stay) and valve selection (type and size) was not affected by the surgical approach either. CONCLUSIONS: AVR can be safely conducted through a partial ministernotomy. This approach is not associated with an increased rate of complications. However, wide CIs reflect the still prevailing statistical uncertainty in estimates, not excluding patient-relevant differences between approaches. Large trials, which also address end points, such as postoperative pain, duration of postoperative recovery and quality of life, are needed to clarify the role of minimally invasive AVR.