Abstract P234: Cost-Effectiveness of Platelet Reactivity Testing in Clopidogrel Exposed Patients Scheduled for Coronary Artery Bypass Surgery

Background: Coronary artery bypass surgery (CABG) is typically delayed until 5 days after last clopidogrel dose, waiting for restoration of platelet reactivity units (PRU). We have investigated cost-effectiveness of CABG timing strategy involving daily platelet PRU testing and operating when platelet inhibition (PI) is less than 30%. Material and Methods: All consenting patients underwent daily PRU testing with point of care VerifyNow P2Y12 assay after receiving 600 mg of clopidogrel at the time of catheterization. Twenty-four hour interval was given between integrillin administration and testing. 29 patients (41% females, 34% with diabetes) comprised study cohort. Daily hospital cost for room and board was $3,770; cost of PRU testing was $49.The study was approved by the institutional IRB. Results: 83% of patients were operated on day 6 after the last clopidogrel dose; an additional 5 patients waited for more than 6 days. At least 75% of the tested patients demonstrated less than 30% PI, traditionally considered “safe” for a surgical intervention. There were no significant differences in RBC (p=0.949) or platelet (p=0.864) transfusion, fresh frozen plasma (p=0.295) or cryoprecipitate (p=0.654) administration in patients whose surgery was delayed for more than 6 days. Employing a strategy of operating on the day when PI is less than 30%, time to the surgery can be decreased from 5.3+/- 0.6 days to 2.8+/-1.5 days, Mann-Whitney p Conclusions: Unless dictated by other clinical considerations, delaying CABG beyond 5 days after last clopidogrel dose is not justified. Five day waiting period is excessive with the majority of clopidogrel-treated patients achieving “safe” platelet responsiveness in less than 5 days. A strategy, involving daily platelet reactivity testing and performing CABG when PI is less than 30%, promises to bring significant cost-savings without compromising quality of delivered care.