Should ticagrelor be taken with aspirin after PCI?

Ticagrelor plus acetylsalicylic acid (aspirin) demonstrates comparable antithrombotic potency to ticagrelor monotherapy in terms of ex vivo blood thrombogenicity among high-risk patients receiving drug-eluting stents, reveals a study. In contrast, markers sensitive to cyclo-oxygenase-1 blockade are higher in the absence of aspirin.

This mechanistic substudy within the TWILIGHT* trial randomly assigned patients undergoing percutaneous coronary intervention (PCI) to either ticagrelor plus aspirin or ticagrelor plus placebo following 3 months of dual antiplatelet therapy.

Substudy participants were enrolled following randomization, in which ex vivo assays to quantify thrombus size under dynamic flow conditions and platelet reactivity were carried out. The investigators repeated pharmacodynamic assessments 1 to 6 months subsequently and performed analysis of covariance to analyse results.

Fifty-one patients were included, of whom 42 underwent perfusion assays at baseline and follow-up, with a median time of 1.5 months between studies. There was comparable adjusted mean difference in postrandomization thrombus area between patients receiving ticagrelor with and without aspirin (−218.2 μm², 95 percent confidence interval [CI], −575.9 to 139.9 μm²; p=0.22).

Patients receiving placebo showed higher markers sensitive to cyclo-oxygenase-1 blockade, including platelet reactivity in response to arachidonic acid (mean difference, 10.9 U, 95 percent CI, 1.9–19.9 U) and collagen (mean difference, 9.8 U, 95 percent CI, 0.8–18.8 U) stimuli. On the other hand, platelet reactivity levels were similar with adenosine diphosphate and thrombin.

“An evolving strategy in the setting of PCI involves withdrawal of acetylsalicylic acid, or aspirin, while maintaining P2Y₁₂ inhibition,” the investigators noted.

*Ticagrelor With Aspirin or Alone in High-Risk Patients After Coronary Intervention