Related Experiment Video
Updated: Jun 21, 2026
Microfluidics in Assessing Platelet Function
Published on: November 8, 2024
Platelet inhibition assessed with VerifyNow, flow cytometry and PlateletMapping in patients undergoing heart surgery
Ulrica Alström1, Fredrik Granath, Jonas Oldgren
1Department of Cardiac and Thoracic Anesthesia and Surgery, Uppsala University Hospital, SE-75185 Uppsala, Sweden. u.a@surgsci.uu
Insights
Dual anti-platelet therapy discontinuation before cardiac surgery showed modest agreement between platelet inhibition tests. VerifyNowP2Y(12) correlated with bleeding and transfusion needs, but isn't helpful for individual patient risk assessment.
Area of Science:
- Cardiovascular medicine
- Hematology
- Surgical oncology
Background:
- Many patients with coronary artery disease undergo cardiac surgery shortly after stopping dual anti-platelet therapy (aspirin and clopidogrel).
- Assessing platelet inhibition is crucial for managing bleeding risks in these patients.
Purpose of the Study:
- To evaluate platelet inhibition levels in patients undergoing coronary artery bypass graft (CABG) surgery after dual anti-platelet therapy.
- To determine if measured platelet inhibition correlates with intra- and postoperative bleeding and transfusion requirements.
Main Methods:
- Sixty patients undergoing CABG surgery were included.
- Platelet inhibition was assessed using flow cytometry (VASP-assay) and two point-of-care devices: VerifyNow-System and PlateletMapping.
- All patients were tested with VerifyNow and PlateletMapping; a subset also underwent flow cytometry.
Main Results:
- A modest correlation was observed between the VASP-assay and VerifyNowP2Y(12) for ADP-receptor inhibition.
- VerifyNowP2Y(12) was the only assay that correlated with total blood loss and red blood cell transfusion requirements.
- Aprotinin treatment may have confounded the correlation between VerifyNowP2Y(12) and bleeding/transfusion outcomes.
Conclusions:
- There was limited agreement among the different methods used to measure preoperative platelet inhibition.
- Preoperative platelet inhibition measured by VerifyNowP2Y(12) correlated with surgical bleeding and transfusion needs.
- VerifyNowP2Y(12) is not currently a reliable tool for predicting individual patient bleeding or transfusion risk.
Introduction:
A substantial number of patients with coronary artery disease undergo cardiac surgery within five days of discontinuing anti-platelet treatment with aspirin and clopidogrel. The aims of this study were to describe the degree of platelet inhibition in patients with dual anti-platelet treatment scheduled for coronary artery bypass graft (CABG) surgery and to investigate whether the measured platelet inhibition correlated to intra- and postoperative risk for bleeding and transfusion requirements.
Material And Methods:
Sixty patients were included. Platelet inhibition was analysed with flow cytometry including phosphorylation status of the vasodilator-stimulated phosphoprotein (VASP-assay) and two bed-side analyzers, VerifyNow-System and PlateletMapping, a modified thrombelastograph. All 60 patients were analysed with VerifyNow and PlateletMapping, and 48 were analysed with flow cytometry and VASP-assay.
Results:
There was a correlation between the ADP-receptor inhibition as measured by VASP-assay and VerifyNowP2Y(12) (r = -0.29, p<0.05), and between VASP-assay and the expression of P-selectin (r = 0.29, p<0.05) as measured by flow cytometry when platelets were stimulated with 5 microM ADP. VerifyNowP2Y(12) was the only measurement of platelet inhibition correlated to total blood loss (Spearman r = 0.29, p=0.03) and red blood cell transfusion (Spearman r = 0.43, p<0.01) requirements, although this might be confounded by aprotinin treatment.
Conclusion:
We found a modest agreement between the methods for preoperative platelet inhibition, though not for PlateletMapping-MA(ADP). There was a correlation between preoperative platelet inhibition measured by VerifyNowP2Y(12) and surgical blood loss or transfusion requirements. However, for the individual patient, preoperative use of VerifyNowP2Y(12) as an instrument to decide bleeding and transfusion risk does not seem helpful.
