Long-term safety and efficacy of low-dose clopidogrel in Japanese patients undergoing coronary stenting: a preliminary study

Low-dose antiplatelet therapy survey after intracerebral hemorrhage in China: a retrospective hospital-based study

Restarting of antiplatelet therapy (AT) for patients with a history of intracerebral hemorrhage (ICH) is still a clinical dilemma in China. We aimed to investigate the association between low-dose AT and the long-term clinical outcome in Chinese ICH patients. A total of 312 patients with a history of ICH were retrospectively enrolled and followed. The ischemic vascular events, recurrent ICH, and all-cause death were reviewed retrospectively. We explored the predictors of ischemic vascular events and recurrent ICH from all patients using Cox proportional hazard regression model. One hundred fifty-one (48.4%) patients were treated with low-dose AT, and the median duration of follow-up was 4.0 years (interquartile range, 2.5-5 years). Compared to 30 (19.8%) of 151 participants who restarted low-dose AT had ischemic vascular events, 51 (31.7%) of 161 participants who did not receive AT showed ischemic vascular events (p=0.025). Eighteen (11.9%) of 151 participants treated with low-dose AT had recurrent ICH and 21 (13.0%) of 161 in non-AT participants (p=0.830). Cox regression analysis also showed that diabetes mellitus was an independent risk factor for ischemic vascular events (p=0.029). Uncontrolled blood pressure (BP) was independently associated with the risk for both ischemic vascular events (p=0.025) and recurrent ICH (p=0.001). Atrial fibrillation (AF) was an independent risk factor for recurrent ICH among patients with a history of ICH (p=0.018). In a Chinese population of patients with predominantly deep, mild to moderate severity ICH, restarting of low-dose AT at a median of 6.2 months was associated with a lower risk of ischemic vascular events without increased risk of recurrent ICH.

Evaluation of pharmacokinetic, pharmacodynamic, efficacy, and safety data of low-dose ticagrelor versus standard dose in East Asians: a systematic review

East Asians are prone to higher systemic exposure and increased risk of bleeding compared to other races after administration of antiplatelet agent(s). The aim of this systematic review was to compare and evaluate the appropriateness of a lower dose versus standard dose of ticagrelor in East Asians. A systematic search was conducted in PubMed, EMBASE, and Cochrane databases for studies comparing low versus standard doses of ticagrelor in East Asian populations; a total of seven studies were included in the review. Pharmacokinetic (PK), pharmacodynamic (PD), clinical efficacy, and safety data were collected. PK data demonstrated that the C_max and area under the curve (AUC) of ticagrelor increased dose-proportionally. PD data indicated that while the low dose of ticagrelor resulted in less antiplatelet activity in three of the five PD studies, in the other studies, there were no differences between low and standard doses. There were two clinical studies included in this review, which showed that the efficacy was similar between the low and standard doses, but both studies were limited by the number of patients included. While there were generally greater incidence of adverse events observed in the standard ticagrelor dose, the magnitude or actual difference between the two doses is difficult to determine due to lack of consistent data. In East Asians, the appropriateness of the low-dose ticagrelor cannot be determined based on the currently available evidence. Additional large-scale and longer duration studies are warranted.

Efficacy and safety of low-dose clopidogrel in Japanese patients after drug-eluting stent implantation: a randomized pilot trial

In Japan, a lower maintenance dose of ticlopidine is used than in the United States and Europe. Therefore a lower maintenance dose of clopidogrel may also be considered appropriate in Japanese patients. The present randomized pilot study evaluated the efficacy and safety of 50 mg clopidogrel in Japanese patients who underwent drug-eluting stent (DES) implantation. A total of 200 patients with 277 lesions who underwent intravascular ultrasound-guided DES implantation were enrolled. The subjects were allocated to the 50- or 75-mg clopidogrel group. All patients received 100 mg aspirin daily before the procedure, and this continued indefinitely. The duration of clinical follow-up was 21.8 ± 5.7 months in the 75-mg group and 21.9 ± 6.1 months in the 50-mg group (P = 0.96). During follow-up, no cardiac death, myocardial infarction, or stent thrombosis was observed in either group. Side effects of clopidogrel were observed in 4 patients (4.0 %) in the 75-mg group and in 4 patients (4.0 %) in the 50-mg group. Following this randomized pilot study, it may be justified to perform a large-scale randomized study comparing 50- and 75-mg dosing of clopidogrel in Japanese patients undergoing coronary stent implantation.