The role of point-of-care assessment of platelet function in predicting postoperative bleeding and transfusion requirements after coronary artery bypass grafting

OBJECTIVE: Objective platelet function assessment after cardiac surgery can predict postoperative blood loss, guide transfusion requirements and discriminate the need for surgical re-exploration. We conducted this study to assess the predictive value of point-of-care testing platelet function using the Multiplate(®) device. METHODS: Patients undergoing isolated coronary artery bypass grafting were prospectively recruited (n = 84). Group A (n = 42) patients were on anti-platelet therapy until surgery; patients in Group B (n = 42) stopped anti-platelet treatment at least 5 days preoperatively. Multiplate(®) and thromboelastography (TEG) tests were performed in the perioperative period. Primary end-point was excessive bleeding (>2.5 ml/kg/h) within first 3 h postoperative. Secondary end-points included transfusion requirements, re-exploration rates, intensive care unit and in-hospital stays. RESULTS: Patients in Group A had excessive bleeding (59% vs. 33%, P = 0.02), higher re-exploration rates (14% vs. 0%, P < 0.01) and higher rate of blood (41% vs. 14%, P < 0.01) and platelet (14% vs. 2%, P = 0.05) transfusions. On multivariate analysis, preoperative platelet function testing was the most significant predictor of excessive bleeding (odds ratio [OR]: 2.3, P = 0.08), need for blood (OR: 5.5, P < 0.01) and platelet transfusion (OR: 15.1, P < 0.01). Postoperative “ASPI test” best predicted the need for transfusion (sensitivity - 0.86) and excessive blood loss (sensitivity - 0.81). TEG results did not correlate well with any of these outcome measures. CONCLUSIONS: Peri-operative platelet functional assessment with Multiplate(®) was the strongest predictor for bleeding and transfusion requirements in patients on anti-platelet therapy until the time of surgery. Study registration: ISRCTN43298975 (http://www.controlled-trials.com/ISRCTN43298975/).