For patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) who received a ticagrelor loading dose, platelet reactivity (PR) assessed by the vasodilator-stimulated phosphoprotein index (VASP) did not predict major adverse cardiac (MACE) or bleeding events, according to study results published in the Journal of Thrombosis and Haemostasis.

The aim of this prospective, observational, multicenter study was to assess the relationship between ticagrelor-inhibited PR and thrombotic and bleeding events in a cohort of patients with ACS receiving PCI. Patients were included after admission to the hospital for ACS, with or without persistent stent thrombosis (ST)-segment elevation, and after a successful PCI of the problem lesion.

Patients received an intravenous bolus of aspirin 250 mg plus a loading dose of ticagrelor 180 mg and then continued ticagrelor 90 mg twice daily, in addition to aspirin 75-100 mg once daily for 12 months. Researchers measured PR by analyzing whole blood samples collected 6-12 hours after the loading dose of ticagrelor using the vasodilator-stimulated phosphoprotein PR index. During the 30-day follow-up time frame, researchers collected data using outpatient visits and telephone conversations. Primary endpoints were definite acute ST, recurrent ACS, stroke, and cardiovascular death. The safety endpoint was defined by Bleeding Academic Research Consortium (BARC) type ≥2.


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Of the 530 patients included in this study, 80.6% were men, the mean age was 64±12.7 years old, 34.5% presented with ST-segment elevation myocardial infarction, 56.4% had hypertension, 42.8% had hypercholesterolemia, and 35.7% had diabetes mellitus. After the loading dose of ticagrelor, the PR, measured by the mean vasodilator-stimulated phosphoprotein index, was 19.1%±16.6%; high on-treatment PR was exhibited in 5.3% of patients, and low on-treatment PR was exhibited in 55.8% of patients.

At the 30-day follow-up, 1.9% of patients reported recurring ACS, 0.9% reported definite acute ST, 0.4% reported a stroke, cardiovascular death occurred in 0.7% of patients, and 5.5% reported a BARC≥2 bleeding event.

No relationship was noted between PR and the occurrence of MACE (P =.34) or a BARC≥2 bleeding event (P =.78), but an association was found between PR and definite acute ST (P =.03).

Patients with a PR >23% were at a greater risk for a definite acute ST than patients with a lower PR (odds ratio 11.11; 95% CI, 1.23-100.3; P =.02).

Limitations of this study include the short follow-up time frame, only assessing a single assay to evaluate PR, and the inability to perform a multivariate analysis because of the lower number of patients with an ST.

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The researchers concluded that “patients receiving a ticagrelor [loading dose] while undergoing PCI for ACS, PR using the [vasodilator-stimulated phosphoprotein index] did not predict MACE or bleeding, but it was significantly associated with the occurrence of definite acute [ST].”

Disclosure: This clinical trial was supported by AstraZeneca Pharmaceuticals LP. Please see the original reference for a full list of authors’ disclosures.

Reference

Laine M, Panagides V, Frère C, et al. Platelet reactivity inhibition following ticagrelor loading dose in patients undergoing percutaneous coronary intervention for acute coronary syndrome [published online July 27, 2019]. J Thromb Haemost. doi:10.1111/jth.14592