Indexed on: 27 Feb '14Published on: 27 Feb '14Published in: Journal of investigative medicine : the official publication of the American Federation for Clinical Research
The current standard of care is to delay noncardiac procedure (NCP) 5 to 7 days after discontinuation of antiplatelet agents (APAs) in patients with coronary stents. However, it is often difficult to follow because of concerns over stent thrombosis. The point-of-care aspirin/P2Y(12) assay (VerifyNow; Accumetrics Inc, San Diego, CA) is useful to evaluate platelet reactivity in conjunction with APAs. In this study, we evaluated the feasible timing after discontinuation of APAs.Sixty-two patients taking APAs, who were scheduled to undergo elective NCP, were enrolled. All patients took either aspirin 100 mg or aspirin 100 mg plus clopidogrel 75 mg daily. The aspirin-reactivity unit (ARU) and P2Y(12)-reactivity unit (PRU) were measured from 0 days (day 0, no discontinuation) to as long as 5 days (day 5, 5 days after discontinuation) depending on each procedure schedule. For 15 patients, baseline ARU and PRU (592 and 288) before aspirin/clopidogrel loading at index percutaneous coronary intervention were collected as control. For ARU after discontinuation of APA, days 0 to 5 values progressively increased over time (489.4 T 85.3, 512.6 T 77.0, 589.9 T 58.8, 613.6 T 47.3, 632.6 T 49.2, 662.0 T 4.2). Likewise, for PRUs, days 0 to 5 values also increased over time (245.0 T 96.9, 253.9 T 80.9, 270.9 T 45.8, 289.0 T 68.6, 306.5 T 29.2, 351.0 T 8.5). The ARU and PRU well correlated with days after APA discontinuation by linear regression analysis ( y = 490.897 + 39.238 * x, R(2) = 0.43, P G 0.001; y = 241.739 + 16.701 * x, R(2) = 0.092, P = 0.018, respectively). Assuming baseline ARU and PRU as 592 and 288, the mean days after complete reversal of platelet reactivity by APAs are 2.6 and 2.8, respectively.The feasible timing of NCP after discontinuation of APAs showed less than 5 days. VerifyNow is useful in the evaluation of antiplatelet reversal after discontinuation of APAs. .