Background:In the ARCTIC trial (Assessment by a Double Randomization of a Conventional Antiplatelet Strategy Versus a Monitoring-Guided Strategy for Drug-Eluting Stent Implantation and of Treatment Interruption Versus Continuation One Year After Stenting), treatment adjustment following platelet function testing failed to improve clinical outcomes. However, high-on-treatment platelet reactivity (HPR) is considered as a predictor of poor ischemic outcome. This prespecified substudy evaluated clinical outcomes according to the residual platelet reactivity status after antiplatelet therapy adjustment.Methods:We analyzed the 1213 patients assigned to the monitoring arm of the ARCTIC trial in whom platelet reactivity was evaluated by the VerifyNow P2Y₁₂ test before percutaneous coronary intervention and during the maintenance phase (at 14 days). HPR was defined as platelet reaction unit≥235U. The primary ischemic end point, a composite of death, myocardial infarction, stent thrombosis, stroke, or urgent revascularization and the safety end point of major bleeding were assessed according to the platelet reactivity status.Results:Before percutaneous coronary intervention, 35.7% of patients displayed HPR (n=419). During the acute phase, between percutaneous coronary intervention and the 14-day platelet function testing, ischemic (adjusted hazard ratio, 0.94 [95% CI, 0.74–1.18]; P=0.58) and safety outcomes (hazard ratio, 1.28 [95% CI, 0.22–7.59]; P=0.78) were similar in HPR and non-HPR patients. During the maintenance phase, the proportion of HPR patients (n=186, 17.4%) decreased by 56%. At 1-year, there was no difference for the ischemic end point (5.9% versus 6.0%; adjusted hazard ratio, 0.79 [95% CI, 0.40–1.58]; P=0.51) and a nonsignificant higher rate of major bleedings (2.7% versus 1.0%, hazard ratio, 2.83 [95% CI, 0.96–8.41]; P=0.06) in HPR versus non-HPR patients.Conclusions:The proportion of HPR was halved after platelet function testing and treatment adjustment but without significant ischemic benefit at 1 year. HPR seems more as a modifiable risk marker than a risk factor of ischemic outcome.Clinical Trial Registration:URL: https://www.clinicaltrials.gov. Unique identifier: NCT00827411.

中文翻译：

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血小板功能测试无法调整抗血小板治疗的原因：来自ARCTIC研究的药效学见解。

背景：在ARCTIC试验中（常规抗血小板策略与药物洗脱支架植入和治疗中断的监测指导策略（在支架置入后一年继续进行）的双重随机评估）中，血小板功能测试后的治疗调整未能改善临床结果。然而，高治疗性血小板反应性（HPR）被认为是缺血性预后不良的预测指标。该预先设定的子研究根据抗血小板治疗调整后的残余血小板反应性状态评估临床结局。方法：我们分析了1213例入ARCTIC试验监测组的患者，他们通过VerifyNow P2Y ₁₂评估了血小板反应性在经皮冠状动脉介入治疗之前和维持阶段（第14天）进行测试。HPR定义为血小板反应单位≥235U。根据血小板反应性状况，评估主要的缺血性终点，死亡，心肌梗死，支架血栓，中风或紧急血运重建的综合因素以及大出血的安全性终点。结果：经皮冠状动脉介入治疗前，有35.7％的患者显示的HPR（n = 419）。在急性期，从经皮冠状动脉介入治疗到14天血小板功能测试之间，缺血（调整后的危险比，0.94 [95％CI，0.74–1.18]；P = 0.58）和安全性结果（危险比，1.28 [95％]） CI，0.22-7.59]；P= 0.78）在HPR和非HPR患者中相似。在维持阶段，HPR患者的比例（n = 186，17.4％）下降了56％。在1年时，缺血终点无差异（5.9％比6.0％；调整后的危险比，0.79 [95％CI，0.40-1.58]；P = 0.51），大出血率无统计学意义（2.7）相对于非HPR患者，HPR的风险百分比为1.0％，风险比为2.83 [95％CI，0.96-8.41]；P = 0.06）。结论：血小板功能测试和治疗调整后，HPR的比例减半，但无明显缺血性1年受益。HPR似乎更是一种可改变的危险标志物，而不是缺血性结局的危险因素。临床试验注册：URL：https://www.clinicaltrials.gov。唯一标识符：NCT00827411。