Comparison of VerifyNow-P2Y12 test and Flow Cytometry for monitoring individual platelet response to clopidogrel. What is the cut-off value for identifying patients who are low responders to clopidogrel therapy?

doi:10.1186/1477-9560-7-4

Thrombosis Journal

Volume 7

Viewing options:

Abstract
Full text
PDF (1.1MB)

Associated material:

Related literature:

Articles citing this article
on Google Scholar
on PubMed Central
Other articles by authors
on Google Scholar

Godino C
Mendolicchio L
Figini F
Latib A
Sharp AS
Cosgrave J
Calori G
Cera M
Chieffo A
Castelli A
Maseri A
Ruggeri ZM
Colombo A

on PubMed

Godino C
Mendolicchio L
Figini F
Latib A
Sharp AS
Cosgrave J
Calori G
Cera M
Chieffo A
Castelli A
Maseri A
Ruggeri ZM
Colombo A
Related articles/pages
on Google

on Google Scholar

on PubMed

Tools:

Post to:

Original clinical investigation

Comparison of VerifyNow-P2Y₁₂test and Flow Cytometry for monitoring individual platelet response to clopidogrel. What is the cut-off value for identifying patients who are low responders to clopidogrel therapy?

Cosmo Godino¹^,2 , Loredana Mendolicchio¹ , Filippo Figini¹ , Azeem Latib¹ , Andrew SP Sharp² , John Cosgrave² , Giliola Calori³ , Michela Cera¹ , Alaide Chieffo¹ , Alfredo Castelli¹ , Attilio Maseri¹ , Zaverio M Ruggeri⁴ and Antonio Colombo¹^,2

¹Department of Cardio-Thoracic and Vascular Diseases, San Raffaele Scientific Institute, Milan, Italy

²GVM Emo Centro Cuore Columbus, Milan, Italy

³Epidemiology and Medical Statistics Unit, San Raffaele Scientific Institute, Milan, Italy

⁴The Scripps Research Institute, Department of Molecular and Experimental Medicine, La Jolla, California, USA

author email corresponding author email

Thrombosis Journal 2009, 7:4doi:10.1186/1477-9560-7-4


Published:	6 May 2009

Abstract

Background

Dual anti-platelet therapy with aspirin and a thienopyridine (DAT) is used to prevent stent thrombosis after percutaneous coronary intervention (PCI). Low response to clopidogrel therapy (LR) occurs, but laboratory tests have a controversial role in the identification of this condition.

Methods

We studied LR in patients with stable angina undergoing elective PCI, all on DAT for at least 7 days, by comparing: 1) Flow cytometry (FC) to measure platelet membrane expression of P-selectin (CD62P) and PAC-1 binding following double stimulation with ADP and collagen type I either in the presence of prostaglandin (PG) E₁; 2) VerifyNow-P2Y₁₂test, in which results are reported as absolute P2Y₁₂-Reaction-Units (PRU) or % of inhibition (% inhibition).

Results

Thirty controls and 52 patients were analyzed. The median percentage of platelets exhibiting CD62P expression and PAC-1 binding by FC evaluation after stimulation in the presence of PG E₁was 25.4% (IQR: 21.4–33.1%) and 3.5% (1.7–9.4%), respectively. Only 6 patients receiving DAT (11.5%) had both values above the 1^stquartile of controls, and were defined as LR. Evaluation of the same patients with the VerifyNow-P2Y₁₂test revealed that the area under the receiver-operating-characteristic (ROC) curve was 0.94 (95% CI: 0.84–0.98, p < 0.0001) for % inhibition and 0.85 (0.72–0.93, p < 0.005) for PRU. Cut-off values of ≤ 15% inhibition or > 213 PRU gave the maximum accuracy for the detection of patients defined as having LR by FC.

Conclusion

In conclusion our findings show that a cut-off value of ≤ 15% inhibition or > 213 PRU in the VerifyNow-P2Y₁₂test may provide the best accuracy for the identification of patients with LR.