Comparison of platelet reactivity between prasugrel and ticagrelor in patients with acute coronary syndrome: a meta-analysis.

BACKGROUND This meta-analysis aimed to compare the effects of prasugrel and ticagrelor on high (HTPR) and low on-treatment platelet reactivity (LTPR) in patients with acute coronary syndrome (ACS). METHODS Eligible studies were retrieved from PubMed, Embase, and the Cochrane Library. HTPR and LTPR were evaluated on the basis of the vasodilator-stimulated phosphoprotein platelet reactivity index (VASP-PRI) and P2Y12 reaction units (PRUs). HTPR and LTPR were analyzed using risk ratios (RRs) and their 95% confidence intervals (CIs). Weighted mean difference (WMD) and 95% CI were used to calculate the pooled effect size of platelet reactivity (PR). RESULTS Fourteen eligible studies were obtained, which included 2629 patients treated with ticagrelor (n = 1340) and prasugrel (n = 1289). The pooled results showed that the prasugrel-treated patients had higher platelet reactivity than the ticagrelor-treated patients (PRU: WMD = - 32.26; 95% CI: - 56.48 to - 8.76; P < 0.01; VASP-PRI: WMD = - 9.61; 95% CI: - 14.63 to - 4.60; P = 0.002). No significant difference in HTPR based on PRU was identified between the ticagrelor and prasugrel groups (P = 0.71), whereas a lower HTPR based on VASP-PRI was found in the ticagrelor-treated patients than in the prasugrel-treated patients (RR = 0.30; 95% CI: 0.12-0.75; P = 0.010). In addition, the results showed a lower LTPR was observed in the prasugrel group than in the ticagrelor group (RR = 1.40; 95% CI: 1.08-1.81; P = 0.01). CONCLUSIONS Prasugrel might enable higher platelet reactivity than ticagrelor. Ticagrelor could lead to a decrease in HTPR and increase in LTPR. However, this result was only obtained in pooled observational studies. Several uncertainties such as the nondeterminancy of the effectiveness of ticagrelor estimated using VASP-PRI or the definition of HTPR (a high or modifiable risk factor) might have affected our results.