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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 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]

Importance: The role of vascular closure devices (VCD) for the achievement of hemostasis in patients undergoing transfemoral coronary angiography remains controversial.Objective: To compare outcomes with the use of 2 hemostasis strategies after diagnostic coronary angiography performed via transfemoral access-a VCD-based strategy with 2 types of devices, an intravascular device and an extravascular device, vs standard manual compression. The primary hypothesis to be tested was that femoral hemostasis achieved through VCD is noninferior to manual compression in terms of vascular access-site complications. A secondary objective was the comparison of the 2 types of VCD.Design, Setting, and Participants: Randomized, large-scale, multicenter, open-label clinical trial. We enrolled 4524 patients undergoing coronary angiography with a 6 French sheath via the common femoral artery from April 2011 through May 2014 in 4 centers in Germany. Last 30-day follow-up was performed in July 2014.Interventions: After angiography of the access site, patients were randomized to hemostasis with an intravascular VCD, extravascular VCD, or manual compression in a 1:1:1 ratio.Main Outcomes and Measures: Primary end point: the composite of access site-related vascular complications at 30 days after randomization with a 2% noninferiority margin. Secondary end points: time to hemostasis, repeat manual compression, and VCD failure. An α-level of .025 was chosen for primary and secondary comparisons.Results: Of the 4524 enrolled patients, 3015 were randomly assigned to a VCD group (1509 received intravascular VCD and 1506 received extravascular VCD) and 1509 patients were randomly assigned to the manual compression group. Before hospital discharge, duplex sonography of the access site was performed in 4231 (94%) patients. The primary end point was observed in 208 patients (6.9%) assigned to receive a VCD and 119 patients (7.9%) assigned to manual compression (difference, -1.0% [1-sided 97.5% CI, 0.7%]; P for noninferiority<.001). Time to hemostasis was significantly shorter in patients with VCD (1 minute [interquartile range {IQR}, 0.5-2.0]), vs manual compression (10 minutes [IQR, 10-15]; P < .001). Time to hemostasis was significantly shorter among patients with intravascular VCD (0.5 minute [IQR, 0.2-1.0]), vs extravascular VCD (2.0 minutes [IQR, 1.0-2.0]; P <.001) and closure device failure was also significantly lower among those with intravascular vs extravascular VCD (80 patients [5.3%], vs 184 patients [12.2%]; P < .001).Conclusions and Relevance: In patients undergoing transfemoral coronary angiography, VCDs were noninferior to manual compression in terms of vascular access-site complications and reduced time to hemostasis.Trial Registration: clinicaltrials.gov Identifier: NCT01389375. [ABSTRACT FROM AUTHOR]

IMPORTANCE The role of vascular closure devices (VCD) for the achievement of hemostasis in patients undergoing transfemoral coronary angiography remains controversial. OBJECTIVE To compare outcomes with the use of 2 hemostasis strategies after diagnostic coronary angiography performed via transfemoral access--a VCD-based strategy with 2 types of devices, an intravascular device and an extravascular device, vs standard manual compression. The primary hypothesis to be tested was that femoral hemostasis achieved through VCD is noninferior to manual compression in terms of vascular access--site complications. A secondary objective was the comparison of the 2 types of VCD. DESIGN, SETTING, AND PARTICIPANTS Randomized, large-scale, multicenter, open-label clinical trial. We enrolled 4524 patients undergoing coronary angiography with a 6 French sheath via the common femoral artery from April 2011 through May 2014 in 4 centers in Germany. Last 30-day follow-up was performed in July 2014. INTERVENTIONS After angiography of the access site, patients were randomized to hemostasis with an intravascular VCD, extravascular VCD, or manual compression in a 1:1:1 ratio. MAIN OUTCOMES AND MEASURES Primary end point: the composite of access site--related vascular complications at 30 days after randomization with a 2%noninferiority margin. Secondary end points: time to hemostasis, repeat manual compression, and VCD failure. An α-level of .025 was chosen for primary and secondary comparisons. RESULTS Of the 4524 enrolled patients, 3015 were randomly assigned to a VCD group (1509 received intravascular VCD and 1506 received extravascular VCD) and 1509 patients were randomly assigned to the manual compression group. Before hospital discharge, duplex sonography of the access site was performed in 4231 (94%) patients. The primary end point was observed in 208 patients (6.9%) assigned to receive a VCD and 119 patients (7.9%) assigned to manual compression (difference, --1.0% [1-sided 97.5%CI, 0.7%]; P for noninferiority <.001). Time to hemostasis was significantly shorter in patients with VCD (1 minute [interquartile range {IQR}, 0.5-2.0]), vs manual compression (10 minutes [IQR, 10-15]; P < .001). Time to hemostasis was significantly shorter among patients with intravascular VCD (0.5 minute [IQR, 0.2-1.0]), vs extravascular VCD (2.0 minutes [IQR, 1.0-2.0]; P <.001) and closure device failure was also significantly lower among those with intravascular vs extravascular VCD (80 patients [5.3%], vs 184 patients [12.2%]; P < .001). CONCLUSIONS AND RELEVANCE In patients undergoing transfemoral coronary angiography, VCDs were noninferior to manual compression in terms of vascular access-site complications and reduced time to hemostasis. [ABSTRACT FROM AUTHOR]

A response by Doctors Stefanie Schulz-Schüpke and Adnan Kastrati to a letter to the editor about their article on the benefit of vascular closure devices following femoral artery puncture in an early 2015 issue is presented.

BACKGROUND: The benefit:risk profile of bivalirudin versus heparin anticoagulation in patients with non--ST-segment--elevation myocardial infarction undergoing percutaneous coronary intervention (PCI) is uncertain. Study-level meta-analyses lack granularity to provide conclusive answers. We sought to compare the outcomes of bivalirudin and heparin in patients with non--ST-segment--elevation myocardial infarction undergoing PCI. METHODS: We performed an individual patient data meta-analysis of patients with non--ST-segment--elevation myocardial infarction in all 5 trials that randomized ≥1000 patients with any myocardial infarction undergoing PCI to bivalirudin versus heparin (MATRIX [Minimizing Adverse Hemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox], VALIDATE-SWEDEHEART [Bivalirudin Versus Heparin in ST-Segment and Non--ST-Segment Elevation Myocardial Infarction in Patients on Modern Antiplatelet Therapy in the Swedish Web System for Enhancement and Development of Evidence- Based Care in Heart Disease Evaluated According to Recommended Therapies Registry Trial], ISAR-REACT 4 [Intracoronary Stenting and Antithrombotic Regimen: Rapid Early Action for Coronary Treatment 4], ACUITY [Acute Catheterization and Urgent Intervention Triage Strategy], and BRIGHT [Bivalirudin in Acute Myocardial Infarction vs Heparin and GPI Plus Heparin Trial]). The primary effectiveness and safety end points were 30-day all-cause mortality and serious bleeding. RESULTS: A total of 12 155 patients were randomized: 6040 to bivalirudin (52.3% with a post-PCI bivalirudin infusion), and 6115 to heparin (53.2% with planned glycoprotein IIb/IIIa inhibitor use). Thirty-day mortality was not significantly different between bivalirudin and heparin (1.2% versus 1.1%; adjusted odds ratio, 1.24 [95% CI, 0.86--1.79]; P=0.25). Cardiac mortality, reinfarction, and stent thrombosis rates were also not significantly different. Bivalirudin reduced serious bleeding (both access site--related and non--access site--related) compared with heparin (3.3% versus 5.5%; adjusted odds ratio, 0.59; 95% CI, 0.48--0.72; P<0.0001). Outcomes were consistent regardless of use of a post-PCI bivalirudin infusion or routine lycoprotein IIb/IIIa inhibitor use with heparin and during 1-year follow-up. CONCLUSIONS: In patients with non--ST-segment--elevation myocardial infarction undergoing PCI, procedural anticoagulation with bivalirudin and heparin did not result in significantly different rates of mortality or ischemic events, including stent thrombosis and reinfarction. Bivalirudin reduced serious bleeding compared with heparin arising both from the access site and nonaccess sites. [ABSTRACT FROM AUTHOR]

The efficacy and safety of ticagrelor versus prasugrel according to smoking status in patients with acute coronary syndromes (ACS) are not known. We assessed the efficacy and safety of ticagrelor versus prasugrel according to smoking status in patients with ACS undergoing invasive management. This pre-specified analysis of the ISAR-REACT 5 trial included 1349 smokers and 2652 nonsmokers randomized to receive ticagrelor or prasugrel. The primary endpoint was the incidence of death, myocardial infarction, or stroke; the secondary endpoint was the incidence of Bleeding Academic Research Consortium (BARC) type 3 to 5 bleeding (both endpoints assessed at 12 months). There was no significant treatment arm-by-smoking status interaction regarding the efficacy outcome. The primary endpoint occurred in 47 patients (7.0%) in the ticagrelor group and 41 patients (6.2%) in the prasugrel group in smokers (hazard ratio [HR] = 1.15; 95% confidence interval [CI] 0.76–1.75; P = 0.510) and in 133 patients (10.2%) in the ticagrelor group and 94 patients (7.2%) in the prasugrel group in nonsmokers (HR = 1.44 [1.10–1.87]; P = 0.007; P for interaction = 0.378). The secondary endpoint occurred in 27 patients (4.6%) in the ticagrelor group and 33 patients (5.6%) in the prasugrel group in smokers (HR = 0.81 [0.49–1.35]; P = 0.412) and in 66 patients (6.0%) in the ticagrelor group and 46 patients (4.4%) in the prasugrel group in nonsmokers (HR = 1.38 [0.94–2.01]; P = 0.097). In patients with ACS undergoing an invasive management strategy, the smoking status did not significantly interact with the relative treatment effect of ticagrelor vs. prasugrel. NCT01944800 • In ACS patients, ticagrelor and prasugrel showed similar efficacy regardless of smoking status. • Bleeding risk was comparable between ticagrelor and prasugrel in smokers and nonsmokers. • Smoking status does not interfere with the relative treatment effect of ticagrelor vs. prasugrel. [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]

Background: Whether there are sex differences in the outcome of patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) remains controversial. We undertook this study to assess whether there are sex-related differences in the long-term mortality in a large series of patients with CAD after PCI.Methods: The study included 18,334 patients (4735 women and 13,599 men) with CAD treated with PCI. Propensity matching was performed to obtain a group of patients (3000 women and 3000 men) matched for all characteristics available in database. The primary outcome was a composite of cardiac mortality, myocardial infarction or stroke at 3 years of follow-up.Results: The primary outcome occurred in 660 women and 1440 men (Kaplan-Meier [KM] estimates, 15.2% in women and 11.6% in men, unadjusted hazard ratio [HR] = 1.35, 95% confidence interval [CI] 1.24 to 1.49; P < 0.001). Women were at higher risk of all-cause mortality (15.4% vs. 12.3%; P < 0.001), cardiac mortality (10.2% vs. 7.6%; P < 0.001) and stroke (2.6% vs. 1.4%; P < 0.001) than men. In matched patients, the primary outcome occurred in 371 women and 322 men (KM estimates, 13.4% vs. 11.6%, HR = 1.18 [1.01-1.36], P = 0.033). Women were at higher risk of myocardial infarction (4.2% vs. 3.1%; P = 0.044) but not cardiac (8.7% vs. 8.2%; P = 0.306) or all-cause death (12.5% vs. 12.9%; P = 0.991) or stroke (1.9% vs. 1.6%; P = 0.550) than men.Conclusions: After propensity matching, women remained at a higher risk of a composite of cardiac mortality, myocardial infarction or stroke up to 3 years after PCI than men. [ABSTRACT FROM AUTHOR]

Background: In the ISAR-CABG (Is Drug-Eluting-Stenting Associated with Improved Results in Coronary Artery Bypass Grafts?) trial, clinical outcomes at 1 year in patients undergoing treatment of saphenous vein graft lesions were superior with drug-eluting stents (DES) versus bare-metal stents.Objectives: The authors compared outcomes between treatment groups at 5 years.Methods: Patients were randomized (1:1:1:3) to receive DES (either permanent-polymer paclitaxel-eluting stents, permanent-polymer sirolimus-eluting stents, or biodegradable-polymer sirolimus-eluting stents) or bare-metal stents. The primary endpoint was the combined incidence of death, myocardial infarction (MI), or target lesion revascularization (TLR). Secondary endpoints were the composite of death or MI and TLR.Results: A total of 610 patients were allocated to treatment with DES (n = 303) or bare-metal stents (n = 307). At 5 years, the primary endpoint occurred in 159 (55.5%) versus 157 (53.6%) patients in the DES and bare-metal stent groups, respectively (hazard ratio [HR]: 0.98; 95% confidence interval [CI]: 0.79 to 1.23; p = 0.89). There was interaction between treatment effect and time (pinteraction = 0.005), with a lower event rate in the DES group at 1 year (HR: 0.64; 95% CI: 0.44 to 0.94; p = 0.02) but a numerically higher rate between 1 and 5 years (HR: 1.24; 95% CI: 0.94 to 1.63; p = 0.13). Death or MI occurred in 93 (32.8%) versus 108 (36.6%) patients, respectively (HR: 0.85; 95% CI: 0.64 to 1.12; p = 0.24), without significant interaction between treatment effect and time (pinteraction = 0.57). TLR occurred in 84 (33.1%) versus 69 (25.5%) patients in the DES and bare-metal stent groups, respectively (HR: 1.20; 95% CI: 0.87 to 1.64; p = 0.27). There was interaction between treatment effect and time (pinteraction <0.001): TLR was significantly lower in the DES group at 1 year (HR: 0.49; 95% CI: 0.28 to 0.86; p = 0.01) but significantly higher thereafter (HR: 2.02; 95% CI: 1.32 to 3.08; p = 0.001).Conclusions: In patients undergoing treatment of saphenous vein graft lesions, the advantage of DES over bare-metal stents demonstrated at 1 year was lost at 5 years due to higher attrition of efficacy in the DES group. (Efficacy Study of Drug-Eluting and Bare Metal Stents in Bypass Graft Lesions [ISAR-CABG]; NCT00611910). [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. 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]

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]