Implications of the VerifyNow P2Y12 Assay on Patient Outcomes

Gregory S. King,Denise A. Sutter,Marintha R. Short

doi:10.4236/ojts.2014.43016

Abstract

Background: The platelet inhibitory response of clopidogrel is substantially variable among patients, and numerous studies have shown that post-percutaneous intervention, patients with high on-treatment platelet reactivity have an increase in risk of major adverse cardiovascular events. No published studies to date have utilized platelet function monitoring assays prior to coronary artery bypass graft (CABG) surgery, but determination of patients’ antiplatelet effects prior to surgery may decrease time to surgery and length of hospital stay. The purpose of the study was to evaluate the clinical outcomes of non-elective CABG patients analyzed by the VerifyNow P2Y12 platelet-function monitoring assay prior to surgery compared to a similar set of patients not analyzed by the VerifyNow P2Y12 assay. Methods: This was a retrospective, single center, cohort study. The primary endpoints of this study were time to surgery and length of hospital stay. Results: From March 2013 to July 2013, 60 patient charts were reviewed and included in this study. 49 patients were analyzed by the VerfiyNow P2Y12 assay, and 16 of these patients underwent non-elective CABG surgery. Eleven patients underwent non-elective CABG surgery and were not analyzed by the VerifyNow P2Y12 assay. There was no difference between groups regarding time to surgery (p = 0.75) or length of stay (p = 0.42). Based on the assay’s P2Y12 reaction unit results, 69% of VerifyNow P2Y12 patients went to surgery sooner than the institution’s recommendations which generated more bleeding events, half of which were considered major bleeds. Conclusions: Utilization of the VerifyNow P2Y12 assay prior to non-elective CABG surgery does not shorten time to surgery or overall length of hospital stay. However, insufficient P2Y12 reaction units prior to surgery may lead to more bleeding events, thus the application of platelet function monitoring assays prior to procedures may be beneficial as a bleeding risk-assessment tool.

Highlights

Dual anti-platelet therapy is part of the standard of care provided to acute coronary syndrome (ACS) patients
The ACCF/AHA guidelines for coronary artery bypass graft (CABG) surgery recommend patients referred for elective CABG discontinue clopidogrel and ticagrelor for at least 5 days prior to surgery and prasugrel for at least 7 days to limit bleeding complications
Numerous studies have shown that high on-treatment platelet reactivity with clopidogrel is associated with an increased risk of cardiovascular events after percutaneous coronary intervention (PCI) [7]-[11]

Summary

Introduction

Dual anti-platelet therapy is part of the standard of care provided to acute coronary syndrome (ACS) patients. Numerous studies have shown that high on-treatment platelet reactivity with clopidogrel is associated with an increased risk of cardiovascular events (e.g. cardiovascular death, nonfatal myocardial infarction, stent thrombosis) after PCI [7]-[11] Through these findings, platelet function monitoring assays have been developed to provide better risk stratification of patients and to help guide clinical decisions. LTA has proven to be time-consuming, requires intensive sample preparation by an experienced technician, and the results are not instantaneous [12] [13] In lieu of these disadvantages, alternative platelet function assays have been developed to provide point-of-care testing. No published studies to date have utilized platelet function monitoring assays prior to coronary artery bypass graft (CABG) surgery, but determination of patients’ antiplatelet effects prior to surgery may decrease time to surgery and length of hospital stay. Insufficient P2Y12 reaction units prior to surgery may lead to more bleeding events, the application of platelet function monitoring assays prior to procedures may be beneficial as a bleeding risk-assessment tool

Objectives

Methods

Results

Conclusion