Platelet reactivity after receiving clopidogrel compared with ticagrelor in patients with kidney failure treated with hemodialysis: a randomized crossover study

Background: Patients with kidney failure treated with maintenance hemodialysis (HD) are poor responders to clopidogrel. More beneficial platelet-inhibiting strategies in HD patients therefore are required.

Study design: Single-center, prospective, randomized, crossover study.

Setting & participants: 25 HD patients in Seoul, Korea.

Intervention: Patients were randomly assigned to receive clopidogrel (300mg loading, 75mg once daily for maintenance dose) or ticagrelor (180mg loading, 90mg twice daily for maintenance dose) for 14 days, and after a 14-day washout period, crossover treatment for another 14 days. All patients received aspirin (100mg/d).

Outcomes & measurements: Platelet function was evaluated predosing and at 1, 5, and 48 hours and 14 days after the first loading dose. During the offset phase, platelet function was assessed at 1 hour and 2, 4, and 14 days after the last dose by light transmittance aggregometry and the VerifyNow P2Y12 assay, and patients were genotyped for the CYP2C19*2 allele. Maximal extent of aggregation, inhibition of platelet aggregation (IPA), P2Y12 reaction units (PRUs), and percentage of inhibition were evaluated. We performed per-protocol analysis, excluding patients who did not complete the protocol.

Results: 9 patients did not complete the protocol (7 patients due to adverse events; 2, nonadherence). Higher IPA occurred with ticagrelor than with clopidogrel at 1, 5, and 48 hours and 14 days after loading. By 5 hours after loading, a greater proportion of patients in the ticagrelor group than in the clopidogrel group achieved IPA>50% (75% vs 12%, respectively; P<0.05) and IPA>70% (44% vs 0%, respectively; P<0.05). Rates (slope) of onset and offset of the antiplatelet effect were faster in patients receiving ticagrelor than for those receiving clopidogrel (P<0.05). Regardless of CYP2C19*2 allele, the ticagrelor group had significantly lower PRUs at all times than the clopidogrel group.

Limitations: Single-center study with a small number of patients, not a double-blind study, and not intention-to-treat analysis.

Conclusions: Ticagrelor may result in more rapid and greater platelet inhibition than clopidogrel in patients with kidney failure receiving HD.