High residual platelet reactivity during aspirin therapy in patients with non-st segment elevation acute coronary syndrome: Comparison between initial and late phases

Background: High platelet reactivity (HPR) during therapy with acetylsalicylic acid (ASA) is a poor prognostic factor in acute coronary syndromes (ACS). The prevalence of HPR during ACS is greater than that reported in stable diseases. However, it is unclear whether this prevalence of HPR is a transient phenomenon or a characteristic of this high-risk population. Objective; The main objective is to compare the effects of ASA on platelet function in the initial and late phases of ACS in a single population. Secondary objectives are: correlation between the tests between themselves and the relationship between the tests and the variation of the inflammatory markers (C-reactive protein and interleukin-6). Methods: Seventy patients with non-ST segment elevation (NSTE) ACS in use of 100-200 mg of ASA per day for at least 7 days were prospectively studied. Platelet function was assessed in the first 48 hours and subsequently after 3 months using four methods: VerifyNow (TM) (VFN), whole blood platelet aggregation (WBPA) with arachidonic acid (AA) and collagen as agonists, and platelet function analyzer (PFA). The level of statistical significance considered was < 0.05. Results: According to the more specific methods (WBPA with AA and VFN), the incidence of HPR was significantly higher in the early phase than in the late phase: WBPA with AA: 31% versus 13%, p = 0.015; VFN: 32% versus 16%, p = 0.049. The other methods tested, which were less specific for ASA, did not show significant differences between phases. The correlation between the methods was weak or moderate (r ranging from 0.3 to 0.5, p < 0.05), and there were no significant associations between HPR and inflammatory markers. Conclusion: The prevalence of HPR during AAS therapy, assessed by specific methods for cyclooxygenase 1 (COX-1), is higher during the acute phase than in the late phase of NSTE ACS

What is the Optimal Duration of Dual Antiplatelet Therapy After Stenting?

The optimal duration of dual antiplatelet therapy (DAPT) of aspirin and a P2Y12 receptor blocker after stenting is still being debated. The current recommendations for DAPT duration are significantly focused on reducing stent thrombosis; a less frequent event with later than earlier generation drug eluting stents (DES). A persistent occurrence of late and very late stent thrombosis with first generation DES supported extended use of DAPT beyond one year. However, recent studies have demonstrated that extended duration DAPT is associated with increased bleeding; an independent predictor for poor outcomes, including long-term mortality. Second-generation DES are associated with less late and very late stent thrombosis. Some recent studies have supported a shorter duration of DAPT for second generation DES. However, these studies were inadequately powered to assess significant differences in stent thrombosis. Furthermore, extended duration DAPT has been associated with a reduced risk of thrombotic events in non-culprit vessels in addition to stent thrombosis in patients with acute coronary syndromes (ACS). The higher risk of bleeding associated with extended DAPT therapy provides a strong rationale for personalized DAPT based on patient risk factors (e.g. ACS vs. non-ACS), type of stents, and cost-benefit analyses

Acetylsalicylic acid and clopidogrel hyporesponsiveness following acute coronary syndromes

This review discusses the response variability to acetylsalicylic acid (ASA) and particularly to clopidogrel, and their relation to adverse recurrent ischaemic events in patients with arterial diseases. The higher rate of ASA resistance reported in the literature may be mainly due to the cyclooxygenase-1 non-specific assays, non-compliance, and underdosing. Clopidogrel response variability and non-responsiveness are established concepts. Moreover, high platelet reactivity (HPR) to adenosine diphosphate during clopidogrel therapy is now a known risk factor for recurrent ischaemic events in high-risk percutaneous coronary intervention/acute coronary syndrome patients. Variable active metabolite generation is the primary explanation for clopidogrel response variability and non-responsivenes. Variable levels of active metabolite generation following clopidogrel administration could be mainly explained by functional variability in hepatic cytochrome (CYP)P450 isoenzyme activity that is influenced by drug–drug interactions and single nucleotide polymorphisms of specific genes encoding CYP450 isoenzymes. Treatment with more potent P2Y12 receptor blockers, such as prasugrel and ticagrelor are credible alternative strategies to overcome HPR during clopidogrel therapy

Increased Risk in Patients With High Platelet Aggregation Receiving Chronic Clopidogrel Therapy Undergoing Percutaneous Coronary Intervention Is the Current Antiplatelet Therapy Adequate?

ObjectivesWe sought to determine whether patients receiving chronic clopidogrel therapy undergoing nonemergent stenting who display high on-treatment preprocedural platelet aggregation measured by standard light transmittance aggregometry and thrombelastography (TEG) will be at increased risk for poststenting ischemic events.BackgroundPatients exhibiting heightened platelet reactivity to adenosine diphosphate (ADP) might be at increased risk for recurrent ischemic events after coronary stenting.MethodsA total of 100 consecutive patients receiving chronic antiplatelet therapy consisting of aspirin (325 mg qd) and clopidogrel (75 mg qd) were studied before undergoing nonemergent stenting. Patients were followed for 1 year after coronary stenting for the occurrence of death, myocardial infarction, stent thrombosis, stroke, or ischemia requiring a hospital stay.ResultsAll patients were aspirin responsive. Patients with ischemic events (23 of 100, 23%) within 1 year had greater on-treatment prestent ADP-induced platelet aggregation than patients without ischemic events by aggregometry and TEG (p < 0.001 for both measurements). Of patients with an ischemic event, 70% and 87% displayed high on-treatment platelet reactivity at baseline by aggregometry and TEG, respectively. High on-treatment platelet reactivity as measured by aggregometry and TEG were the only variables significantly related to ischemic events (p < 0.001 for both assays). The administration of eptifibatide reduced periprocedural elevation in platelet reactivity, with no significant differences in bleeding events.ConclusionsPatients receiving chronic clopidogrel therapy undergoing nonemergent percutaneous coronary intervention who exhibit high on-treatment ADP-induced platelet aggregation are at increased risk for postprocedural ischemic events. These findings might have implications for the alteration in clopidogrel maintenance dose and use of glycoprotein IIb/IIIa inhibitors in selected patients

Updated evidence on intracoronary abciximab in ST-elevation myocardial infarction: A systematic review and meta-analysis of randomized clinical trials

Abstract Background: Intracoronary (IC) abciximab administration remains a promising approach aimed to increase a drug concentration in the target area and possibly improve clinical outcomes in the setting of ST-segment elevation myocardial infarction (STEMI). The goal of this literature review and meta-analysis is to update available knowledge comparing IC and intravenous (IV) abciximab administration in STEMI patients. Methods: A total of 7 randomized clinical trials (RCTs) with a median follow-up of 3 months were included in the meta-analysis (n = 3311). All-cause mortality was selected as the primary end point while recurrent myocardial infarction (re-MI), target vessel revascularization (TVR) and major bleeding complications were the secondary end points. Results: IC abciximab did not provide any benefits in terms of all-cause mortality as compared with IV abciximab (odds ratio [OR] 0.67; 95% confidence interval [CI] 0.34 1.34). However, this neutral effect was driven by the AIDA STEMI trial. The IC route was associated with a reduced rate of re-MI when compared with IV administration (OR 0.61; 95% CI 0.40 0.92) but the difference disappeared after one of the RCTs was excluded from the analysis. Both strategies were equal regarding TVR (OR 0.66; 95% CI 0.40 1.09) and major bleeding complications (OR 1.18; 95% CI 0.76 1.83). Conclusions: Our updated meta-analysis shows that the clinical superiority of IC over IV abciximab administration in STEMI patients is no longer clear after the release of the AIDA STEMI trial results. Further research in high-risk STEMI patients is warranted to finally determine clinical advantages of IC vs IV abciximab administration. (Cardiol J 2012; 19, 3:230 242

Incidence of Dyspnea and Assessment of Cardiac and Pulmonary Function in Patients With Stable Coronary Artery Disease Receiving Ticagrelor, Clopidogrel, or Placebo in the ONSET/OFFSET Study

ObjectivesWe prospectively assessed cardiac and pulmonary function in patients with stable coronary artery disease (CAD) treated with ticagrelor, clopidogrel, or placebo in the ONSET/OFFSET (A Multi-Centre Randomised, Double-Blind, Double-Dummy Parallel Group Study of the Onset and Offset of Antiplatelet Effects of AZD6140 Compared With Clopidogrel and Placebo With Aspirin as Background Therapy in Patients With Stable Coronary Artery Disease) study.BackgroundTicagrelor reduces cardiovascular events more effectively than clopidogrel in patients with acute coronary syndromes. Dyspnea develops in some patients treated with ticagrelor, and it is not known whether this is associated with changes in cardiac or pulmonary function.MethodsIn all, 123 stable aspirin-treated CAD patients randomly received either ticagrelor (180 mg load, then 90 mg twice daily; n = 57), clopidogrel (600 mg load, then 75 mg daily; n = 54), or placebo (n = 12) for 6 weeks in a double-blind, double-dummy design. Electrocardiography, echocardiography, serum N-terminal pro-brain natriuretic peptide, and pulmonary function tests were performed before (baseline) and 6 weeks after drug administration and/or after development of dyspnea.ResultsAfter drug administration, dyspnea was reported by 38.6%, 9.3%, and 8.3% of patients in the ticagrelor, clopidogrel, and placebo groups, respectively (p < 0.001). Most instances were mild and/or lasted <24 h, although 3 patients discontinued ticagrelor because of dyspnea. Eight of 22 and 17 of 22 ticagrelor-treated patients experiencing dyspnea did so within 24 h and 1 week, respectively, after drug administration. In all treatment groups, and in ticagrelor-treated patients with dyspnea, there were no significant changes between baseline and 6 weeks in any of the cardiac or pulmonary function parameters.ConclusionsDyspnea is commonly associated with ticagrelor therapy, but was not associated in this study with any adverse change in cardiac or pulmonary function. (A Multi-Centre Randomised, Double-Blind, Double-Dummy Parallel Group Study of the Onset and Offset of Antiplatelet Effects of AZD6140 Compared With Clopidogrel and Placebo With Aspirin as Background Therapy in Patients With Stable Coronary Artery Disease [ONSET/OFFSET]; NCT00528411

PAR1 (Protease-Activated Receptor 1) Pepducin Therapy Targeting Myocardial Necrosis in Coronary Artery Disease and Acute Coronary Syndrome Patients Undergoing Cardiac Catheterization: A Randomized, Placebo-Controlled, Phase 2 Study

OBJECTIVE: Arterial thrombosis leading to ischemic injury worsens the prognosis of many patients with cardiovascular disease. PZ-128 is a first-in-class pepducin that reversibly inhibits PAR1 (protease-activated receptor 1) on platelets and other vascular cells by targeting the intracellular surface of the receptor. The TRIP-PCI (Thrombin Receptor Inhibitory Pepducin in Percutaneous Coronary Intervention) trial was conducted to assess the safety and efficacy of PZ-128 in patients undergoing cardiac catheterization with intent to perform percutaneous coronary intervention. Approach and Results: In this randomized, double-blind, placebo-controlled, phase 2 trial, 100 patients were randomly assigned (2:1) to receive PZ-128 (0.3 or 0.5 mg/kg), or placebo in a 2-hour infusion initiated just before the start of cardiac catheterization, on top of standard oral antiplatelet therapy. Rates of the primary end point of bleeding were not different between the combined PZ-128 doses (1.6%, 1/62) and placebo group (0%, 0/35). The secondary end points of major adverse coronary events at 30 and 90 days did not significantly differ but were numerically lower in the PZ-128 groups (0% and 2% in the PZ-128 groups, 6% and 6% with placebo, p=0.13, p=0.29, respectively). In the subgroup of patients with elevated baseline cardiac troponin I, the exploratory end point of 30-day major adverse coronary events + myocardial injury showed 83% events in the placebo group versus 31% events in the combined PZ-128 drug groups, an adjusted relative risk of 0.14 (95% CI, 0.02-0.75); P=0.02. CONCLUSIONS: In this first-in-patient experience, PZ-128 added to standard antiplatelet therapy appeared to be safe, well tolerated, and potentially reduced periprocedural myonecrosis, thus providing the basis for further clinical trials. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02561000