Individual short-term responses to antiplatelet therapy vary

(HealthDay)—For patients with ischemic heart disease, responses to antiplatelet therapy (APT) vary between pre-discharge and one week after discharge from hospital, according to a study published online March 21 in the Journal of Thrombosis and Haemostasis.

Vikram Khanna, B.M., from the University of Southampton in the United Kingdom, and colleagues examined whether responses to APT varied significantly over time. Forty patients on dual APT underwent simultaneous assay with VerifyNow and Short thrombelastography (s-TEG) before and at four time points over six months following hospital discharge. The authors also measured serum thromboxane B₂ (TXB₂) levels.

The researchers found that aspirin response units by VerifyNow and serum TXB₂ levels remained stable over time. Compared with pre-discharge, arachidonic acid-mediated platelet aggregation with s-TEG increased at one week (P < 0.008). In addition, there were increases at one week in platelet reactivity units by VerifyNow (P = 0.046) and adenosine diphosphate-mediated platelet aggregation with s-TEG (P = 0.026), compared with pre-discharge. Beyond one week there were no significant changes in platelet reactivity or rates of high on-treatment platelet reactivity on clopidogrel.

"In conclusion, this study demonstrates important variability in responses to APT within individuals between pre-discharge and one week but not thereafter," the authors write. "The design of future strategies to assess individual responses for tailored therapy need to take this into account."

One author disclosed financial ties to medical device companies, including Haemonetics Corporation, which supported the study.

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