Comparison of the Antiplatelet Effects of Once and Twice Daily Low-Dose Ticagrelor and Clopidogrel After Percutaneous Coronary Intervention.

Although Asian people are believed to be more susceptible to bleeding on currently recommended dose of ticagrelor, there is limited evidence supporting low-dose ticagrelor. We prospectively randomized patients receiving dual antiplatelet therapy with aspirin and clopidogrel into 3 groups; aspirin plus clopidogrel 75 mg versus aspirin plus ticagrelor 90 mg once daily versus aspirin plus ticagrelor 45 mg twice daily. Platelet function assessments were conducted using VerifyNow P2Y12 assay at baseline and 28 days after randomization. No differences in baseline P2Y12 reaction unit (PRU) values were observed among the 3 groups. PRU values at the end of the treatment periods were significantly lower in low-dose ticagrelor (90 mg QD group, 98.6 ± 73.4 and 45 mg BID group, 65.5 ± 58.8) compared with clopidogrel (221.2 ± 50.1, both p <0.001). There was no significant difference in PRU values between 2 groups of low-dose ticagrelor (p = 0.208). The rates of high on-treatment platelet reactivity were significantly lower in low-dose ticagrelor compared with clopidogrel, whereas clopidogrel showed higher rate of optimal on-treatment platelet reactivity than ticagrelor 45 mg BID. However, similar rate of optimal on-treatment platelet reactivity was observed in clopidogrel and ticagrelor 90 mg QD. In conclusion, low-dose ticagrelor treatment, either with 90 mg QD or 45 mg BID, was associated with a more potent antiplatelet effect compared with clopidogrel treatment and once daily dose provided similar antiplatelet effect but favorable effect on optimal platelet inhibition compared with twice daily dose.

Randomized Comparison of the Platelet Inhibitory Efficacy between Low Dose Prasugrel and Standard Dose Clopidogrel in Patients Who Underwent Percutaneous Coronary Intervention.

BACKGROUND AND OBJECTIVES: Increased bleeding rates with standard dose prasugrel have led to increased questions about the effectiveness and safety of the lower maintenance dose. We compared platelet inhibitory efficacy between low dose prasugrel and standard dose clopidogrel in patients on maintenance dose dual antiplatelet therapy. SUBJECTS AND METHODS: Forty-three patients who underwent percutaneous coronary intervention were randomized to receive 75 mg clopidogrel (n=23) or 5 mg prasugrel (n=20). Another 20 patients were allocated to 10 mg prasugrel as a reference comparison group. All patients (weight, ≥60 kg; age, <75 years) had been receiving 100 mg aspirin and 75 mg clopidogrel daily. The platelet function test was performed at baseline and 30 days after randomization. The primary endpoint was P2Y12 reaction unit (PRU) at 30 days between 5 mg prasugrel and 75 mg clopidogrel. RESULTS: No differences in baseline PRU values were observed among the three groups. The prasugrel (5 mg) group had a significantly lower PRU value compared with that of 75 mg clopidogrel (174.6±60.2 vs. 223.4±72.9, p=0.022) group at 30 days, whereas the 10 mg prasugrel group showed a lower PRU value (71.9±34.4) compared with that of the 5 mg prasugrel (p<0.001). The rate of high on-treatment platelet reactivity (PRU >235) was significant lower in the 5 mg prasugrel group than that in the 75 mg clopidogrel group (15.0% vs. 56.5%, p=0.010). CONCLUSION: Prasugrel (5 mg) is more potent antiplatelet therapy than 75 mg clopidogrel in non-low body weight and non-elderly patients on a maintenance dose dual antiplatelet therapy.

Randomized comparison of new dual-antiplatelet therapy (aspirin, prasugrel) and triple-antiplatelet therapy (aspirin, clopidogrel, cilostazol) using P2Y12 point-of-care assay in patients with STEMI undergoing primary PCI.

BACKGROUND: Both new dual antiplatelet therapy (DAT; aspirin and prasugrel) and triple antiplatelet therapy (TAT; aspirin, clopidogrel and cilostazol) are more potent than classic DAT (aspirin and clopidogrel). We compared the antiplatelet efficacy between new DAT and TAT in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary coronary percutaneous coronary intervention (PCI). METHODS: Forty patients who were eligible for primary PCI were prospectively randomized to DAT group (n=20) or TAT group (n=20) immediately after hospital arrival. The primary end point was P2Y12 reaction unit (PRU) determined with the VerifyNow P2Y12 point-of-care assay at the time of discharge. RESULTS: PRU value at discharge was significantly lower in patients receiving DAT compared with that of TAT (84.5 ± 44.7 vs. 128.4 ± 74.9, p=0.032). Percent platelet inhibition was significantly higher for DAT compared with TAT at discharge (72.1 ± 12.2 vs. 57.5 ± 23.5, p=0.020). Inter-patient variability of PRU values at discharge was significantly smaller in patient taking DAT compared with TAT (p=0.026). CONCLUSION: A new DAT is more potent antiplatelet therapy than TAT in patients with STEMI undergoing primary PCI.

Meta-analysis of three randomized trials and nine observational studies comparing drug-eluting stents versus coronary artery bypass grafting for unprotected left main coronary artery disease.

Clinical outcomes for unprotected left main coronary artery (ULMCA) disease between coronary artery bypass grafting (CABG) and drug-eluting stents (DESs) remain controversial. We aimed to compare the safety and efficacy of percutaneous coronary intervention (PCI) using DESs with CABG in patients with ULMCA disease. Databases were searched for clinical studies that reported outcomes after PCI with DESs and CABG for treatment of ULMCA disease. End points of this meta-analysis were mortality; composite of death, myocardial infarction (MI), or stroke; and target vessel revascularization at 1-year follow-up. Pooled effects were calculated using fixed-effects model (Mantel-Haenszel method) or random-effects models (Dersimonian-Laird method). Twelve clinical studies (3 randomized trials and 9 observational studies) with 5,079 patients were involved in this study. At 1-year follow-up, there were trends toward lower risk of death (odds ratio [OR] 0.68, 95% confidence interval [CI] 0.45 to 1.02) and the composite end point of death, MI, or stroke (OR 0.70, 95% CI 0.49 to 1.00) in the DES group compared to the CABG group. However, target vessel revascularization was significantly higher in the DES group compared to the CABG group (OR 3.52, 95% CI 2.72 to 4.56). In conclusion, PCI with DESs is associated with favorable outcomes for mortality; composite end point of death, MI, or stroke; and a higher risk of target vessel revascularization compared to CABG in patients with ULMCA disease.