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The sample size of a clinical trial has to be large enough to ensure sufficient power for achieving the aim the study. On the other side, for ethical and economical reasons it should not be larger than necessary. The sample size allocation is one of the parameters that influences the required total sample size. For two‐arm superiority and non‐inferiority trials with binary endpoints, we performed extensive computations over a wide range of scenarios to determine the optimal allocation ratio that minimizes the total sample size if all other parameters are fixed. The results demonstrate, that for both superiority and non‐inferiority trials the optimal allocation may deviate considerably from the case of equal sample size in both groups. However, the saving in sample size when allocating the total sample size optimally as compared to balanced allocation is typically small. [ABSTRACT FROM AUTHOR]

BACKGROUND: The comparative efficacy and safety of ticagrelor and prasugrel in patients with acute coronary syndrome undergoing complex percutaneous coronary intervention (PCI) has not been defined. METHODS: This post hoc analysis included all patients with acute coronary syndrome treated with PCI and randomized to either ticagrelor or prasugrel in the ISAR-REACT 5 trial (Intracoronary Stenting and Antithrombotic Regimen: Rapid Early Action for Coronary Treatment). Complex PCI was defined as at least one of the following: multivessel PCI, ≥3 stents implanted, ≥3 lesions treated, and total stented length >60 mm. The primary efficacy end point was the composite of all-cause death, myocardial infarction, or stroke; the safety end point was Bleeding Academic Research Consortium types 3 to 5 bleeding. Outcomes were assessed out to 12 months after randomization. RESULTS: Among the 3377 patients treated with PCI in the ISAR-REACT 5 trial, 1429 underwent complex PCI (ticagrelor, N=696 and prasugrel, N=733) and 1948 underwent noncomplex PCI (ticagrelor, N=980 and prasugrel, N=968). There was no interaction between PCI complexity, assignment to either ticagrelor or prasugrel, and the primary efficacy or safety end points (P for interaction: ≥0.13). In the complex PCI group, the primary efficacy end point (11.0% versus 9.2%, hazard ratio: 1.19 [0.85-1.66], P=0.303) and the safety end point (5.2% versus 6.1%, hazard ratio: 0.83 [0.53-1.31], P=0.419) were not statistically different in patients receiving either ticagrelor or prasugrel. In the noncomplex PCI group, the primary efficacy end point occurred more frequently in patients assigned to ticagrelor as compared to prasugrel (8.9% versus 5.5%, hazard ratio: 1.66 [1.18-2.34], P=0.004) without significant difference in terms of the safety end point (5.4% versus 4.1%, hazard ratio: 1.41 [0.92-2.17], P=0.110). CONCLUSIONS: In patients with acute coronary syndrome, PCI complexity does not influence the comparative efficacy and safety of ticagrelor and prasugrel. The observed comparable performance of ticagrelor and prasugrel in patients with acute coronary syndrome undergoing complex PCI requires further confirmation. [ABSTRACT FROM AUTHOR]

Background: The efficacy and safety of a reduced dose of prasugrel versus a standard dose of ticagrelor in elderly patients or those with a low body weight presenting with an acute coronary syndrome (ACS) are unknown.Objective: To investigate the effect of an age- and weight-adapted dose of prasugrel versus a standard dose of ticagrelor in patients with ACS. (ClinicalTrials.gov: NCT01944800).Design: Prespecified analysis of the multicenter, randomized ISAR-REACT 5 trial.Setting: 23 centers in Germany and Italy.Patients: 3997 patients with ACS planned for invasive management.Intervention: Participants were randomly assigned to receive a standard dose of ticagrelor or prasugrel (reduced dose in the elderly or low-weight group and standard dose in the neither elderly nor low-weight group).Measurements: The efficacy end point was a composite of death, myocardial infarction, or stroke, and the safety end point was bleeding, both at 12 months.Results: In the elderly or low-weight group, the efficacy end point occurred in 12.7% of patients assigned to receive prasugrel and 14.6% of those assigned to receive ticagrelor (hazard ratio [HR], 0.82 [95% CI, 0.60 to 1.14]); in the neither elderly nor low-weight group, the efficacy end point occurred in 4.8% of patients assigned to receive prasugrel and 7.3% of those assigned to receive ticagrelor (HR, 0.65 [CI, 0.48 to 0.88]; P for interaction > 0.2). In the elderly or low-weight group, Bleeding Academic Research Consortium type 3 to 5 bleeding occurred in 8.1% of patients assigned to receive prasugrel and 10.6% of those assigned to receive ticagrelor (HR, 0.72 [0.46 to 1.12]), and in 3.7% and 3.8%, respectively, of patients in the neither elderly nor low-weight group (HR, 0.98 [CI, 0.65 to 1.47]; P for interaction > 0.2).Limitation: The study is a subgroup analysis.Conclusion: In elderly or low-weight patients with ACS, a reduced dose of prasugrel compared with the standard dose of ticagrelor is associated with maintained anti-ischemic efficacy while protecting these patients against the excess risk for bleeding.Primary Funding Source: German Center for Cardiovascular Research and Deutsches Herzzentrum München. [ABSTRACT FROM AUTHOR]

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Background: The relative merits of ticagrelor as compared with prasugrel in patients with acute coronary syndromes for whom invasive evaluation is planned are uncertain.Methods: In this multicenter, randomized, open-label trial, we randomly assigned patients who presented with acute coronary syndromes and for whom invasive evaluation was planned to receive either ticagrelor or prasugrel. The primary end point was the composite of death, myocardial infarction, or stroke at 1 year. A major secondary end point (the safety end point) was bleeding.Results: A total of 4018 patients underwent randomization. A primary end-point event occurred in 184 of 2012 patients (9.3%) in the ticagrelor group and in 137 of 2006 patients (6.9%) in the prasugrel group (hazard ratio, 1.36; 95% confidence interval [CI], 1.09 to 1.70; P = 0.006). The respective incidences of the individual components of the primary end point in the ticagrelor group and the prasugrel group were as follows: death, 4.5% and 3.7%; myocardial infarction, 4.8% and 3.0%; and stroke, 1.1% and 1.0%. Definite or probable stent thrombosis occurred in 1.3% of patients assigned to ticagrelor and 1.0% of patients assigned to prasugrel, and definite stent thrombosis occurred in 1.1% and 0.6%, respectively. Major bleeding (as defined by the Bleeding Academic Research Consortium scale) was observed in 5.4% of patients in the ticagrelor group and in 4.8% of patients in the prasugrel group (hazard ratio, 1.12; 95% CI, 0.83 to 1.51; P = 0.46).Conclusions: Among patients who presented with acute coronary syndromes with or without ST-segment elevation, the incidence of death, myocardial infarction, or stroke was significantly lower among those who received prasugrel than among those who received ticagrelor, and the incidence of major bleeding was not significantly different between the two groups. (Funded by the German Center for Cardiovascular Research and Deutsches Herzzentrum München; ISAR-REACT 5 ClinicalTrials.gov number, NCT01944800.). [ABSTRACT FROM AUTHOR]

Background: We performed an updated meta-analysis of all randomized-controlled trials (RCTs) comparing patent foramen ovale (PFO) closure with medical therapy for prevention of recurrent ischemic stroke.Methods and results: We searched Medline, EMBASE, and Cochrane databases, and proceedings of international meetings for RCTs of patients with cryptogenic stroke and PFO comparing percutaneous PFO closure versus medical therapy for prevention of recurrent ischemic stroke. The primary outcome was a composite ischemic/embolic endpoint comprising stroke, transient ischemic attack (TIA), peripheral embolism, and early death in the intention-to-treat population. Secondary outcomes were all-cause death, stroke, TIA, atrial fibrillation (AF), and major bleeding. Of 3440 enrolled patients across five RCTs, 1829 were allocated to PFO closure and 1611 to medical therapy. The follow-up ranged from 2 to 5.9 years. PFO closure reduced the risk of the composite outcome [HR 0.52, (0.36-0.77); p < 0.01], and stroke, [HR 0.39, (0.19-0.83); p < 0.01], and increased the risk of AF [OR 3.75, (2.44-5.78); p < 0.01] as compared to medical therapy. NNT for stroke was 37 and NNH for AF 49, indicating a net clinical benefit of PFO closure. The meta-analysis had 95% power to detect a 50% relative risk reduction (RRR) in the primary outcome and 89% power to detect a 70% RRR in ischemic stroke. The risk of all-cause death (HR 1.08, p = 0.90), TIA [HR 0.73, (0.49-1.09); p = 0.12], and major bleeding [OR 0.97, (0.44-2.17); p = 0.95] was comparable between the groups.Conclusions: Among patients with cryptogenic stroke and PFO, percutaneous closure of PFO is superior to medical therapy in preventing recurrent ischemic/embolic events and stroke but is associated with an increased risk of AF. [ABSTRACT FROM AUTHOR]

Background Patients with chronic kidney disease (CKD) have elevated bleeding and ischemic outcomes. We aim to assess the short- and long-term efficacy and safety of bivalirudin compared to heparin plus glycoprotein IIb/IIIa inhibitors (GPIs) in coronary artery disease (CAD) patients with CKD. Methods Randomized trials were searched in PubMed, Cochrane, and Embase databases up to January 2017. Among the trials retrieved, efficacy endpoints were defined as mortality, myocardial infarction (MI), repeat revascularization, stent thrombosis, and major adverse cardiac events (MACEs). Safety endpoints were reported as non-coronary artery bypass grafting (CABG) related major bleeding and thrombolysis in myocardial infarction (TIMI) major bleeding. Risk ratio (RR) and 95% confidence interval (CI) were calculated for each outcome using a fixed effect model. Results Five studies with a total of 3796 patients were included. In short-term follow up (30 days), bivalirudin significantly reduced non-CABG related major bleeding ( p = 0.0004) and TIMI major bleeding ( p = 0.007) compared to heparin plus GPIs. No significant differences were observed in rates of mortality, MI, repeat revascularization, stent thrombosis, and MACEs between the two groups in short- and long-term follow up (6 months to 3 years). In patients with ST elevated myocardial infarction (STEMI) with concurrent CKD, the decreased non-CABG related major bleeding ( p = 0.04) without increasing ischemic events was also observed after short-term follow up. Conclusions (1) Bivalirudin is safer than and as effective as heparin plus GPIs in CAD patients with CKD. (2) Impaired renal function does not affect the safety benefits of bivalirudin. (3) Similar efficacy profiles were identified between the two groups after both short- and long-term follow up in the CAD patients with CKD. [ABSTRACT FROM AUTHOR]

Aims The differential impact on ischaemic and bleeding events of the type of drug-eluting stent [durable polymer stents [DES] vs. biodegradable polymer stents vs. bioresorbable scaffolds (BRS)] and length of dual antiplatelet therapy (DAPT) remains to be defined. Methods and results Randomized controlled trials comparing different types of DES and/or DAPT durations were selected. The primary endpoint was Major Adverse Cardiovascular Events (MACE) [a composite of death, myocardial infarction (MI), and target vessel revascularization]. Definite stent thrombosis (ST) and single components of MACE were secondary endpoints. The arms of interest were: BRS with 12 months of DAPT (12mDAPT), biodegradable polymer stent with 12mDAPT, durable polymer stent [everolimus-eluting (EES), zotarolimus-eluting (ZES)] with 12mDAPT, EES/ ZES with <12 months of DAPT, and EES/ZES with >12 months of DAPT (DAPT > 12 m). Sixty-four studies with 150 arms and 102 735 patients were included. After a median follow-up of 20 months, MACE rates were similar in the different arms of interest. EES/ZES with DAPT > 12 m reported a lower incidence of MI than the other groups, while BRS showed a higher rate of ST when compared to EES/ZES, irrespective of DAPT length. A higher risk of major bleedings was observed for DAPT > 12 m as compared to shorter DAPT. Conclusion Durable and biodegradable polymer stents along with BRS report a similar rate of MACE irrespective of DAPT length. Fewer MI are observed with EES/ZES with DAPT > 12 m, while a higher rate of ST is reported for BRS when compared to EES/ZES, independently from DAPT length. Stent type may partially affect the outcome together with DAPT length. [ABSTRACT FROM AUTHOR]

Background: The association between coronary atherosclerosis progression or regression and long-term prognosis remains poorly defined. We assessed the association of atherosclerosis progression or regression with long-term mortality and factors that promote angiographic progression or regression of coronary atherosclerosis in patients with angiographically proven coronary artery disease.Methods: The study included 605 patients with coronary artery disease who underwent coronary angiography at baseline and at 2 years later. Pan-coronary artery tree quantitative coronary angiography was performed. Of 6259 coronary segments (10.3 lesions per patient) analyzed, 1790 non-stented segments with ≥25% diameter stenosis at baseline were included. Atherosclerosis progression or regression was defined as a decrease or increase in the mean minimal lumen diameter (MLD) of the non-stented segments of ≥0.2 mm in the 2-year angiography compared to baseline angiography. The primary outcome was all-cause mortality.Results: Based on the change in mean MLD between baseline and 2-year angiography, patients were divided into 3 groups: the group with progression of atherosclerosis (n=53; 8.8%), the group with no progression or regression of atherosclerosis (n=472; 78.0%) and the group with regression of atherosclerosis (n=80; 13.2%). There were 126 deaths over 8-year follow-up: 17 deaths among patients with progression, 103 deaths among patients with no progression/regression and 6 deaths among patients with regression (Kaplan-Meier estimates of mortality, 37.5%, 25.2% and 8.9%, respectively; adjusted hazard ratio=1.16, 95% confidence interval 1.05 to 1.29, P=.004 for 0.1 mm reduction in mean MLD).Conclusions: Progression or regression of coronary atherosclerosis in non-treated coronary segments was significantly associated with 8-year mortality. [ABSTRACT FROM AUTHOR]

Background. A relevant number of patients receive triple therapy with clopidogrel, aspirin, and oral anticoagulation. Clopidogrel’s efficacy on ADP induced platelet function may be influenced by concomitant antithrombotic therapies. Data regarding the effect of dabigatran on platelet function is limited to in vitro studies and healthy individuals. Methods. The “Dabi-ADP-1” and “Dabi-ADP-2” trials randomized patients with atrial fibrillation to either dabigatran or phenprocoumon for a 2-week period. In Dabi-ADP-1 (n=70) patients with clopidogrel therapy were excluded and in Dabi-ADP-2 (n=46) patients had to be treated concomitantly with clopidogrel. The primary endpoint was ADP-induced platelet aggregation between dabigatran and phenprocoumon at 14 days. Secondary endpoints were ADPtest HS-, TRAP-, and COL-induced platelet aggregation. Results. There was no significant difference regarding the primary endpoint between both groups in either trial (Dabi-ADP-1: Dabigatran: 846 [650–983] AU × min versus phenprocoumon: 839 [666–1039] AU × min, P=0.90 and Dabi-ADP-2: 326 [268–462] versus 350 [214–535], P=0.70) or regarding the secondary endpoints, ADPtest HS-, TRAP-, and COL-induced platelet aggregation. Conclusion. Dabigatran as compared to phenprocoumon has no impact on ADP-induced platelet aggregation in atrial fibrillation patients neither with nor without concomitant clopidogrel therapy. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is available in the text. Background: Even among biomarker-negative patients undergoing elective percutaneous coronary intervention (PCI), periprocedural thrombotic and bleeding complications can lead to increased morbidity and mortality. Whether stronger platelet inhibition by an intensified oral loading strategy (ILS) before PCI impacts on outcomes among these patients in contemporary practice remains unclear. Methods: This multicenter, randomized, assessor-blinded trial tested the hypothesis that in elective PCI prasugrel 60 mg (ILS) is superior to standard loading strategy with clopidogrel 600 mg regarding a composite primary end point of all-cause death, any myocardial infarction, definite/probable stent thrombosis, stroke, or urgent vessel revascularization. After PCI, all patients were on clopidogrel 75 mg/day and aspirin. The trial was terminated prematurely because of slower-than-expected recruitment and funding discontinuation. Results: Of 781 patients included in the final analysis, 382 were assigned to ILS and 399 to standard loading strategy. At 30 days, the primary end point occurred in 66 patients (17.3%) assigned to ILS and 74 patients (18.6%) assigned to standard loading strategy (odds ratio, 0.92 [95% CI, 0.63–1.32]; P =0.64). Any myocardial infarction and Bleeding Academic Research Consortium ≥2 bleeding rates were similar among ILS and standard loading strategy groups 16.2% versus 17.5%, odds ratio, 0.91 (95% CI, 0.62–1.32), P =0.62 and 4.2% versus 4.8%, odds ratio 0.87 (95% CI, 0.44–1.73), P =0.70, respectively. Conclusions: In biomarker-negative stable and unstable angina patients undergoing elective PCI, the trial did not find a conclusive difference in efficacy or safety. This observation should be interpreted in the context of wide CIs and premature termination of the trial. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02548611. [ABSTRACT FROM AUTHOR]

Background: Although some randomized controlled trials (RCTs) and meta-analyses have suggested that prolonged dual-antiplatelet therapy (DAPT) may be associated with increased mortality, the mechanistic underpinnings of this association remain unclear.Objectives: The aim of this study was to analyze the associations among bleeding, mortality, and DAPT duration after drug-eluting stent implantation in a meta-analysis of RCTs.Methods: RCTs comparing different DAPT durations after drug-eluting stent placement were sought through the MEDLINE, Embase, and Cochrane databases and the proceedings of international meetings. Deaths were considered possibly bleeding related if occurring within 1 year of the episodes of bleeding. Primary analysis was by intention-to-treat. Secondary analysis was performed in a modified intention-to-treat population in which events occurring when all patients were on DAPT were excluded.Results: Individual patient data were obtained for 6 RCTs, and aggregate data were available for 12 RCTs. Patients with bleeding had significantly higher rates of mortality compared with those without, and in a time-adjusted multivariate analysis, bleeding was an independent predictor of mortality occurring within 1 year of the bleeding episode (hazard ratio: 6.93; 95% confidence interval: 4.53 to 10.60; p < 0.0001). Shorter DAPT was associated with lower rates of all-cause death compared with longer DAPT (hazard ratio: 0.85; 95% confidence interval: 0.73 to 1.00; p = 0.05), which was driven by lower rates of bleeding-related deaths with shorter DAPT compared with prolonged DAPT (hazard ratio: 0.65; 95% confidence interval: 0.43 to 0.99; p = 0.04). Mortality unrelated to bleeding was comparable between the 2 groups. Similar results were apparent in the modified intention-to-treat population.Conclusions: Bleeding was strongly associated with the occurrence of mortality within 1 year after the bleeding event. Shorter compared with longer DAPT was associated with lower risk for bleeding-related death, a finding that may underlie the lower all-cause mortality with shorter DAPT in the RCTs of different DAPT durations after DES. [ABSTRACT FROM AUTHOR]

Background Patients receiving oral anticoagulation (OAC) who undergo drug-eluting stent (DES) implantation require additional dual antiplatelet therapy with aspirin and clopidogrel. Such triple therapy confers an elevated bleeding risk, and its optimal duration is not known. Objectives The goal of this study was to evaluate whether shortening the duration of clopidogrel therapy from 6 months to 6 weeks after DES implantation was associated with a superior net clinical outcome in patients receiving concomitant aspirin and OAC. Methods In this randomized, open-label trial, we enrolled patients receiving OAC who underwent DES implantation at 3 European centers between September 2008 and December 2013. A total of 614 patients receiving concomitant aspirin and OAC were randomized to either 6-week clopidogrel therapy (n = 307) or 6-month clopidogrel therapy (n = 307). The primary endpoint was a composite of death, myocardial infarction (MI), definite stent thrombosis, stroke, or Thrombolysis In Myocardial Infarction (TIMI) major bleeding at 9 months. Results The primary endpoint occurred in 30 patients (9.8%) in the 6-week group compared with 27 patients (8.8%) in the 6-month group (hazard ratio [HR]: 1.14; 95% CI: 0.68 to 1.91; p = 0.63). There were no significant differences for the secondary combined ischemic endpoint of cardiac death, MI, definite stent thrombosis, and ischemic stroke (12 [4.0%] vs. 13 [4.3%]; HR: 0.93; 95% CI: 0.43 to 2.05; p = 0.87) or the secondary bleeding endpoint of TIMI major bleeding (16 [5.3%] vs. 12 [4.0%]; HR: 1.35; 95% CI: 0.64 to 2.84; p = 0.44). Conclusions Six weeks of triple therapy was not superior to 6 months with respect to net clinical outcomes. These results suggest that physicians should weigh the trade-off between ischemic and bleeding risk when choosing the shorter or longer duration of triple therapy. (Triple Therapy in Patients on Oral Anticoagulation After Drug Eluting Stent Implantation [ISAR-TRIPLE]; NCT00776633 ) [ABSTRACT FROM AUTHOR]