Lack of association between clopidogrel responsiveness tested using point-of-care assay and prognosis of patients with coronary artery disease
Abstract
Dual antiplatelet therapy is important treatment modality across the spectrum of coronary artery disease manifestations. However, a significant number of patients do not have a completely effective response to clopidogrel.
This study assessed the impact of response after clopidogrel with Verify Now device on prognosis on patients undergoing coronary interventions. Consecutive patients following percutaneous coronary intervention were prospectively enrolled.
A loading dose of 600 mg of clopidogrel was administered before or during PCI. Blood samples were drawn within 24 h after clopidogrel administration.
The effect of clopidogrel was measured using VerifyNow. All patients were evaluated at 6 months.
The primary end-point was the combination of death, MI and stroke. 378 patients (69.3 % men and 30.7 % women) were enrolled. The mean age was 67.2 +- 12.8 years, BMI 28.9 +- 17.7, and 116 patients had diabetes (30.7 %).
During the 6-months follow-up 30 patients (7.94 %) experienced a monitored end-point: 12 patients (3.17 %) had MI; five patients (1.32 %) strokes and 15 patients (3.97 %) died. The remaining 248 patients (71.26 %) were end-point free.
Factors associated with a poor prognosis were: leukocytes (OR 1.7 [1.2-2.4], p < 0.01), creatinine (OR 1.4 [1.1-2.5], p < 0.05) and at a borderline level the presence of AA allele of gene CYP2C19*2 (OR 2.5 [0.99-4.1], p = 0.052). The results using VerifyNow were similar between both groups (Group End-point: 208.5 +- 85.5, group No end-point 203.1 +- 91.3) and failed to show any prognostic value (OR 1.00 [0.992-1.007], p = 0.9).
The measurement of clopidogrel efficacy using VerifyNow had no prognostic value for our unselected cohort of patients after PCI