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Updated: Apr 17, 2026
Microfluidics in Assessing Platelet Function
Published on: November 8, 2024
Point-of-care platelet function testing predicts bleeding in patients exposed to clopidogrel undergoing coronary
Grant W Reed1, Amit Kumar, Jianping Guo
1TIMI Study Group, Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts; Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio.
Insights
Point-of-care platelet function testing can predict bleeding risk in patients undergoing coronary artery bypass grafting (CABG) after clopidogrel exposure. This allows for personalized management, potentially improving surgical outcomes.
Area of Science:
- Cardiovascular Surgery
- Hematology
- Pharmacology
Background:
- Current guidelines recommend a 5-day delay between clopidogrel discontinuation and coronary artery bypass grafting (CABG).
- Individual platelet function recovery after clopidogrel cessation can vary significantly.
- This variability poses a challenge for optimizing surgical timing and managing bleeding risk.
Purpose of the Study:
- To investigate the hypothesis that perioperative platelet function assessment can predict bleeding during CABG in patients exposed to clopidogrel.
- To evaluate the utility of a point-of-care P2Y12 inhibitor assay in this context.
- To identify potential cutpoints for predicting bleeding events.
Main Methods:
- A prospective pilot study (Verify Pre-Op TIMI 45) involving 39 patients undergoing CABG after clopidogrel exposure.
- Preoperative platelet reactivity was measured using VerifyNow P2Y12 Reaction Units (PRU).
- Outcomes were analyzed based on PRU quartiles and specific cutpoints (173, 207, 230) for bleeding risk stratification.
Main Results:
- Higher PRU quartiles correlated with smaller hemoglobin/hematocrit decreases and less major/minor bleeding.
- Patients above PRU cutpoints of 207 and 230 exhibited reduced chest-tube output and bleeding.
- Receiver operator curve analysis indicated that a preoperative PRU ≤ 207 effectively discriminated between patients with and without major bleeding (AUC: 0.76, P=0.018).
Conclusions:
- Point-of-care platelet function testing, specifically PRU measurement, can predict bleeding risk in patients undergoing CABG after recent clopidogrel use.
- This assessment may enable more individualized perioperative management strategies.
- Further research is warranted to validate these findings in larger cohorts.
Background:
Guidelines recommend delaying coronary artery bypass grafting (CABG) for 5 days after discontinuing clopidogrel. However, platelet function may recover quicker in certain individuals.
Hypothesis:
We hypothesized that perioperative measurement of platelet function with a point-of-care P2Y12 inhibitor assay could predict bleeding during CABG in patients exposed to clopidogrel.
Methods:
Verify Pre-Op TIMI 45 was a prospective pilot study of 39 patients on clopidogrel who subsequently underwent CABG. Preoperative on-treatment platelet reactivity was assessed with VerifyNow P2Y12 Reaction Units (PRU), with higher PRU indicating more reactive platelets. Outcomes were stratified by PRU quartiles, as well as prespecified cutpoints for the lowest quartile (PRU 173), a cutpoint for major bleeding determined by the Youden index using receiver operator curve analysis (PRU 207), and clopidogrel resistance (PRU 230).
Results:
Patients in higher PRU quartiles experienced smaller decreases in hemoglobin and hematocrit (P < 0.05 for all comparisons), less major bleeding (P = 0.021), and less major or minor bleeding (P = 0.003). Patients above the PRU 207 and 230 cutpoints had less chest-tube output (P = 0.041 and P = 0.012, respectively), less major bleeding (P = 0.005 and P = 0.036, respectively), and less major or minor bleeding (P = 0.013 and P < 0.001, respectively). By receiver operator curve analysis, preoperative PRU ≤ 207 discriminated between patients with and without major bleeding during surgery (area under the curve: 0.76, 95% confidence interval: 0.59-0.94, P = 0.018).
Conclusions:
In this pilot study, we found that point-of-care platelet function assessment could predict bleeding in patients recently exposed to clopidogrel undergoing CABG.
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