Allogeneic blood transfusion requirements after minimally invasive versus conventional aortic valve replacement: a risk-adjusted analysis

BACKGROUND: Aortic valve replacement (AVR) through a partial sternotomy (mini-AVR) has been suggested to significantly reduce postoperative morbidity compared with conventional AVR. This study sought to investigate whether mini-AVR patients require fewer transfusions than patients who had conventional AVR. METHODS: Of 511 patients who had AVR, 56 had mini-AVR and 455 had conventional AVR. A matched-case logistic regression analysis was used to adjust for these imbalances between groups. RESULTS: No patient in the mini-AVR cohort required conversion to a conventional AVR. Cardiopulmonary bypass time was longer in the mini-AVR group compared with the conventional AVR group, with a median of 102 minutes (range, 78 to 119 minutes) versus 75 minutes (range, 61 to 96 minutes; p < 0.01) in the conventional AVR group. A total of 31 patients (55%) in the mini-AVR group and 336 patients (74%) in the conventional sternotomy group required transfusions during their hospital stay (p < 0.01). After adjusting for differences in preoperative risk factors, year of operation, and surgeon, by matching on propensity score, the differences were not statistically significant (odds ratio = 0.84, 95% confidence interval = 0.40 to 1.75, p = 0.63). CONCLUSIONS: Mini-AVR produces better wound cosmesis and less surgical trauma but requires more time to perform. Matched-case analysis failed to show a significant difference in blood transfusion requirements after mini-AVR compared with the conventional AVR approach.