Treatment with ticagrelor did not improve endothelial function or increase systemic adenosine plasma levels compared with prasugrel or clopidogrel in patients with stable post-acute coronary syndrome (ACS), according to results from the HI-TECH study presented on May 24 at EuroPCR in Paris and published in JACC: Cardiovascular Interventions.

In the randomized, open-label, crossover study, Sara Ariotti, MD, et al., examined 54 stable post-ACS patients in five European centers to assess whether treatment with ticagrelor improves endothelium-dependent dilation. Each patient was sequentially exposed to ticagrelor, prasugrel and clopidogrel following a three-period balanced Latin square crossover design with four weeks per treatment. The investigators also measured systemic adenosine plasma levels and several markers of endothelial function.

Results showed that the primary endpoint of reactive hyperemia index did not differ after ticagrelor vs. prasugrel (1.970 vs. 2.007; p=0.557) or vs. clopidogrel (1.970 vs. 2.072; p=0.685). No differences were seen between the drugs for systemic adenosine plasma levels or vascular biomarkers at any time points. Additionally, P2Y12 platelet reactivity units were lower after ticagrelor vs. clopidogrel at all time points and after a maintenance dose vs. prasugrel. Flow-mediated dilatation did not differ after the maintenance dose of ticagrelor vs. clopidogrel and prasugrel.

The authors explain that further research is needed to assess the effect of ticagrelor on tissue adenosine plasma levels in humans compared with other oral P2Y12 inhibitors and its relationship with clinical outcomes.

In an accompanying editorial comment, Jay S. Giri, MD, MPH, and Ashwin Nathan, MD, note that "it is imperative to ascertain whether these medications are accessible for individual patients." They add, "although studies will attempt to identify nuanced differences among different antiplatelet agents to maximize benefits to patients, the best antiplatelet agent in the current era is likely the one the patient can afford to obtain."

Keywords: Platelet Aggregation Inhibitors, Purinergic P2Y Receptor Antagonists, Acute Coronary Syndrome, Cross-Over Studies, Dilatation, Blood Platelets, Research Personnel, Hyperemia, Ticlopidine, Adenosine, Research, Biomarkers, Endothelium

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