Researchers investigated whether monitoring patient responses to oral antiplatelet therapy, and then adjusting the therapy in those with a poor response, might improve outcomes in patients after coronary stenting. A total of 2,440 patients undergoing drug-eluting stent implantation were randomized into this open-label study. Platelet function was not regularly assessed in the conventional treatment group (n = 1,227) and platelet-function evaluations were conducted before stent implantation and for up to four weeks afterward in the monitoring group (n = 1,213); those with an inadequate platelet inhibitory response received antiplatelet drug and dose adjustments.

Monitoring in the evaluation group before stent implantation identified approximately one-third of patients who had high platelet reactivity with clopidogrel treatment; 83% of these received an additional loading dose of antiplatelet therapy during the procedure. Only five patients had high platelet reactivity to aspirin before implantation, and four received an additional bolus of aspirin. Platelet reactivity assessments two and four weeks after implantation revealed that approximately half of patients with a poor response to P2Y12 inhibitors at the time of implantation continued to have this response. Compared with patients in the conventional therapy group, those monitored for platelet functioning were more likely to be receiving a high dose of aspirin, clopidogrel, or prasugrel; a trend that continued during the one-year follow-up.

At one year after stent implantation, the primary end point-a composite of death, myocardial infarction, stroke or transient is-chemic attack, urgent coronary revascularization, and stent thrombosis-had occurred in 35% of patients in the monitored group and 31% of those in the conventional therapy group.

The authors concluded that platelet-function monitoring in patients receiving a coronary stent did not improve outcomes compared with standard care.

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