P2Y12 Assay Identifies Patients at Risk for Blood Transfusion Following Cardiac Surgery

Timing of surgical intervention after administration of P2Y12 inhibitors remains a clinical challenge balancing ischemia and bleeding risks. This study assessed whether preoperative P2Y12 assay results correlate with perioperative transfusions, postoperative chest tube (CT) output, and reoperation for bleeding following cardiac surgery.

All patients undergoing cardiac surgery at a single institution with a preoperative P2Y12 assay value from 2012 to 2022 were included. The P2Y12 assay closest to surgery and relevant bleeding outcomes was obtained. A cutpoint analysis was used to determine a P2Y12 reaction unit (PRU) lab value that identified patients requiring >1 unit of postoperative blood transfusion. A risk-adjusted multivariable regression analyzed bleeding-related outcomes and operative mortality for patients stratified by the PRU cutpoint.

There were 729 patients with a median P2Y12 level of 173.0 PRU, 89% of whom underwent coronary artery bypass grafting. Patients with PRU <194 had a greater decrease in postoperative hematocrit, postoperative day 1 CT output, and average daily CT output. A PRU cutpoint of 101 was selected that classified patients requiring postoperative transfusion of ≥1 unit of packed red blood cell (PRBC). In the risk-adjusted analysis, patients with PRU <101 were found to have higher odds of ≥1 unit postoperative PRBC administration (OR 3.2, 95% CI 1.95-5.44; P < 0.001).

Preoperative P2Y12 assay can help guide the estimation of postoperative bleeding risk. The cutpoint provided by the reference range may be too conservative, and a lower cutpoint can more accurately identify patients at risk of requiring postoperative PRBC transfusion.