Effect of P2Y12 platelet reactivity level on peri- and postoperative outcomes of cardiac surgery patients

BACKGROUND: Evidence surrounding P2Y12 platelet reactivity units (PRU) impact on bleeding outcomes in patients undergoing coronary artery bypass is varied. This study sought to assess whether on-pump CABG procedures result in increased bleeding in patients with high compared to low PRUs. METHODS: This retrospective cohort study compared those with a PRU level ≤237 (low PRU group) to >237 (high PRU group). The primary outcome assessed massive or severe bleeding in accordance with universal definition of perioperative bleeding criteria. Secondary outcomes assessed mortality, length of stay and relevant bleeding related outcomes (e.g., rates of moderate or lower classifications of bleeding, chest tube output, blood product receipt). RESULTS: A total of 69 patients were included, 47 in the low and 22 in the high PRU groups. Patients were a median (IQR) 66 (62-74) years and 84.1% (N.=58) were male. Most patients received clopidogrel prior to procedure (39 [83%] in low and 18 [81.8%] in high PRU group; P=1.0000). The rate of the primary outcome was 14.9% (N.=7) in patients with a low PRU and 18.2% (N.=4) in patients with a high PRU; P=0.7345. The rate of moderate bleeding was 59.6% (N.=28) in the low and 27.3% (N.=6) in the high PRU group (P=0.0124). Packed red blood cells (PRBCs) were administered to more patients in the low (23 [48.9%]) than the high PRU group (2 [22.7%]; P=0.0388). There were no differences in other blood product requirement, chest tube output, factor products administered, mortality, or length of stay. CONCLUSIONS: This study determined that low preoperative P2Y12 PRU levels may influence moderate bleeding in patients undergoing cardiac surgery, but not massive or severe bleeding.