LAUSR

OBJECTIVES Little is known about the safety and clinical utility of retrograde autologous priming (RAP) in patients undergoing minimally invasive mitral valve surgery. The study authors hypothesized that RAP would increase the oxygen delivery index (DO2i) while decreasing red blood cell transfusion requirements compared to valve surgery without RAP. DESIGN The study was an observational analysis. SETTING A single institutional study. PARTICIPANTS The authors analyzed data from 500 consecutive patients who underwent minimally invasive isolated mitral valve repair from December 31, 2012, to December 31, 2019. INTERVENTION RAP was performed in 235 patients (47%) prior to the initiation of cardiopulmonary bypass (CPB). MEASUREMENT AND MAIN RESULTS A continuous monitoring system was used for DO2 management during CPB. The mean arterial pressure was maintained between 55 and 70 mmHg, and the cardiac index was set at 2.4 L/min/m2, with adjustments in accordance with DO2i. The trigger point for red cell blood transfusion during CPB was hemoglobin <7 g/dL. Baseline hematocrit was lower in the RAP group compared to the no-RAP group (33.4 ± 3.6 v 38.1 ± 4.9, respectively; p < 0.001). Both CPB and cross-clamp times were similar between groups. Hematocrit during CPB was significantly higher in the RAP group compared to the no-RAP group (27.6 ± 2.6 v 25.9 ± 5.1, respectively; p < 0.001). RAP was also associated with significantly higher mean DO2i (292 ± 19.5 v 282.9 ± 35.1 mL/min/m2, respectively; p < 0.001) and fewer red blood cells transfusions during the intraoperative and immediate postoperative periods (p < 0.001). CONCLUSIONS In a minimally invasive mitral valve context, RAP was safe and associated with better DO2i, higher hematocrit, and fewer intraoperative and postoperative red blood cell transfusions.