Ticagrelor versus Clopidogrel in Symptomatic Peripheral Artery Disease.

BACKGROUND: Peripheral artery disease is considered to be a manifestation of systemic atherosclerosis with associated adverse cardiovascular and limb events. Data from previous trials have suggested that patients receiving clopidogrel monotherapy had a lower risk of cardiovascular events than those receiving aspirin. We wanted to compare clopidogrel with ticagrelor, a potent antiplatelet agent, in patients with peripheral artery disease. METHODS: In this double-blind, event-driven trial, we randomly assigned 13,885 patients with symptomatic peripheral artery disease to receive monotherapy with ticagrelor (90 mg twice daily) or clopidogrel (75 mg once daily). Patients were eligible if they had an ankle-brachial index (ABI) of 0.80 or less or had undergone previous revascularization of the lower limbs. The primary efficacy end point was a composite of adjudicated cardiovascular death, myocardial infarction, or ischemic stroke. The primary safety end point was major bleeding. The median follow-up was 30 months. RESULTS: The median age of the patients was 66 years, and 72% were men; 43% were enrolled on the basis of the ABI and 57% on the basis of previous revascularization. The mean baseline ABI in all patients was 0.71, 76.6% of the patients had claudication, and 4.6% had critical limb ischemia. The primary efficacy end point occurred in 751 of 6930 patients (10.8%) receiving ticagrelor and in 740 of 6955 (10.6%) receiving clopidogrel (hazard ratio, 1.02; 95% confidence interval [CI], 0.92 to 1.13; P=0.65). In each group, acute limb ischemia occurred in 1.7% of the patients (hazard ratio, 1.03; 95% CI, 0.79 to 1.33; P=0.85) and major bleeding in 1.6% (hazard ratio, 1.10; 95% CI, 0.84 to 1.43; P=0.49). CONCLUSIONS: In patients with symptomatic peripheral artery disease, ticagrelor was not shown to be superior to clopidogrel for the reduction of cardiovascular events. Major bleeding occurred at similar rates among the patients in the two trial groups. (Funded by AstraZeneca; EUCLID ClinicalTrials.gov number, NCT01732822 .).

Ticagrelor Compared With Clopidogrel in Patients With Prior Lower Extremity Revascularization for Peripheral Artery Disease.

BACKGROUND: In patients with symptomatic peripheral artery disease with a history of limb revascularization, the optimal antithrombotic regimen for long-term management is unknown. METHODS: The EUCLID trial (Examining Use of Ticagrelor In PAD) randomized 13 885 patients with peripheral artery disease to treatment with ticagrelor 90 mg twice daily or clopidogrel 75 mg daily. Patients were enrolled based on an abnormal ankle-brachial index ≤0.80 or a previous lower extremity revascularization. This analysis focuses on the 7875 (57%) patients enrolled based on the previous lower extremity revascularization criterion. Patients could not be enrolled within 30 days of most recent revascularization, and patients with an indication for dual antiplatelet therapy were excluded. The primary efficacy end point was a composite of cardiovascular death, myocardial infarction, or ischemic stroke. The primary safety end point was major bleeding. RESULTS: Patients with a previous revascularization had a mean age of 66 years, 73% were male, and the median baseline ankle-brachial index was 0.78. After adjustment for baseline characteristics, patients enrolled based on previous revascularization had similar rates of the primary composite end point (hazard ratio [HR] 1.10, 95% confidence interval [CI] 0.98-1.23, P=0.12) and statistically significantly higher rates of myocardial infarction (HR 1.29, 95% CI 1.08-1.55, P=0.005) and acute limb ischemia (HR 4.23, 95% CI 2.86-6.25, P<0.001) when compared with patients enrolled based on ankle-brachial index criteria. No differences in ticagrelor- versus clopidogrel-treated patients were found for the primary efficacy end point (11.4% vs 11.3%; HR 1.01, 95% CI 0.88-1.15; P=0.90), all-cause mortality (9.2% vs 9.2%; HR 0.99, 95% CI 0.86-1.15; P=0.93), acute limb ischemia (2.5% vs 2.5%; HR 1.03, 95% CI 0.78-1.36; P=0.84), or major bleeding (1.9% vs 1.8%; HR 1.15, 95% CI 0.83-1.59; P=0.41). The median duration of follow-up was ≈30 months. CONCLUSIONS: After adjustment for baseline characteristics, patients enrolled based on previous revascularization for peripheral artery disease had higher rates of myocardial infarction and acute limb ischemia, with similar composite rates of cardiovascular death, myocardial infarction, and stroke when compared with patients enrolled based on the ankle-brachial index criterion. No significant differences were found between ticagrelor and clopidogrel for reduction of cardiovascular or acute limb events. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01732822.

Ezetimibe Added to Statin Therapy after Acute Coronary Syndromes.

BACKGROUND: Statin therapy reduces low-density lipoprotein (LDL) cholesterol levels and the risk of cardiovascular events, but whether the addition of ezetimibe, a nonstatin drug that reduces intestinal cholesterol absorption, can reduce the rate of cardiovascular events further is not known. METHODS: We conducted a double-blind, randomized trial involving 18,144 patients who had been hospitalized for an acute coronary syndrome within the preceding 10 days and had LDL cholesterol levels of 50 to 100 mg per deciliter (1.3 to 2.6 mmol per liter) if they were receiving lipid-lowering therapy or 50 to 125 mg per deciliter (1.3 to 3.2 mmol per liter) if they were not receiving lipid-lowering therapy. The combination of simvastatin (40 mg) and ezetimibe (10 mg) (simvastatin-ezetimibe) was compared with simvastatin (40 mg) and placebo (simvastatin monotherapy). The primary end point was a composite of cardiovascular death, nonfatal myocardial infarction, unstable angina requiring rehospitalization, coronary revascularization (≥30 days after randomization), or nonfatal stroke. The median follow-up was 6 years. RESULTS: The median time-weighted average LDL cholesterol level during the study was 53.7 mg per deciliter (1.4 mmol per liter) in the simvastatin-ezetimibe group, as compared with 69.5 mg per deciliter (1.8 mmol per liter) in the simvastatin-monotherapy group (P<0.001). The Kaplan-Meier event rate for the primary end point at 7 years was 32.7% in the simvastatin-ezetimibe group, as compared with 34.7% in the simvastatin-monotherapy group (absolute risk difference, 2.0 percentage points; hazard ratio, 0.936; 95% confidence interval, 0.89 to 0.99; P=0.016). Rates of prespecified muscle, gallbladder, and hepatic adverse effects and cancer were similar in the two groups. CONCLUSIONS: When added to statin therapy, ezetimibe resulted in incremental lowering of LDL cholesterol levels and improved cardiovascular outcomes. Moreover, lowering LDL cholesterol to levels below previous targets provided additional benefit. (Funded by Merck; IMPROVE-IT ClinicalTrials.gov number, NCT00202878.).

Ticagrelor versus clopidogrel in patients with symptomatic peripheral artery disease and prior coronary artery disease: Insights from the EUCLID trial.

Patients with peripheral artery disease (PAD) are at heightened risk of cardiovascular morbidity and mortality. We sought to evaluate the risk of concomitant coronary artery disease (CAD) in patients with symptomatic PAD versus PAD without diagnosed CAD, and whether ticagrelor was superior to clopidogrel in reducing that risk. The EUCLID trial randomized 13,885 patients with PAD to antithrombotic monotherapy with ticagrelor or clopidogrel. CAD was defined as prior myocardial infarction (MI), percutaneous coronary intervention (PCI), or coronary artery bypass graft (CABG) surgery. Median follow-up was 30 months. Among 4032 (29%) patients with PAD and CAD, 63% had prior MI, 54% prior PCI, and 38% prior CABG. After adjustment for baseline characteristics, patients with PAD and CAD had significantly higher rates of the primary endpoint (cardiovascular death/MI/stroke, 15.3% vs 8.9%, hazard ratio (HR) 1.50, 95% CI: 1.13-1.99; p=0.005), but no statistically significant increase in acute limb ischemia (HR 1.28, 95% CI: 0.57-2.85; p=0.55) or major bleeding (HR 1.10, 95% CI: 0.49-2.48; p=0.81) versus PAD without CAD. Among patients with PAD and CAD, there was no differential treatment effect between ticagrelor versus clopidogrel for the primary efficacy endpoint (HR 1.02, 95% CI: 0.87-1.19; p=0.84), acute limb ischemia (HR 1.03, 95% CI: 0.63-1.69; p=0.89), or major bleeding (HR 1.06, 95% CI: 0.66-1.69; p=0.81). There was a statistically significant interaction between prior coronary stent placement and study treatment ( p=0.03) with a numerical reduction in the primary efficacy endpoint with ticagrelor versus clopidogrel (13.8% vs 16.8%, HR 0.82, 95% CI: 0.65-1.03; p=0.09). Patients with PAD and prior CAD had higher composite rates of cardiovascular death, MI, and ischemic stroke versus PAD without diagnosed CAD. There were no significant differences between ticagrelor and clopidogrel in cardiovascular events or major bleeding. ClinicalTrials.gov Identifier: NCT01732822.

On-treatment analysis of the Improved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT).

BACKGROUND: We aimed to determine the efficacy and safety of adding ezetimibe (Ez) to simvastatin (S) in a post-acute coronary syndrome (ACS) population in a prespecified on-treatment analysis. METHODS: We evaluated 17,706 post-ACS patients from the IMPROVE-IT trial who had low-density lipoprotein cholesterol values between 50 and 125 mg/dL and who received Ez 10 mg/d with S 40 mg/d (Ez/S) or placebo with simvastatin 40 mg/d (P/S). The primary composite end point was cardiovascular death, myocardial infarction, unstable angina, coronary revascularization ≥30 days postrandomization, or stroke. The on-treatment analysis included patients who received study drug for the duration of the trial or experienced a primary end point or noncardiovascular death within 30 days of drug discontinuation. RESULTS: Mean low-density lipoprotein cholesterol values at 1 year were 71 mg/dL for P/S and 54 mg/dL for Ez/S (absolute difference -17 mg/dL = -24%; P < .001). The 7-year Kaplan-Meier estimate of the primary end point occurred in 32.4% in the P/S arm and 29.8% in the Ez/S arm (absolute difference 2.6%; HRadj 0.92 [95% CI 0.87-0.98]; P = .01). The absolute treatment effect favoring Ez/S was 30% greater than in the intention-to-treat analysis of IMPROVE-IT. CONCLUSIONS: This analysis provides additional support for the efficacy and safety of adding Ez to S in this high-risk, post-ACS population.

Design and rationale for the Effects of Ticagrelor and Clopidogrel in Patients with Peripheral Artery Disease (EUCLID) trial.

BACKGROUND: Despite overwhelming data demonstrating the efficacy of antiplatelet therapy in heart disease and stroke, data in peripheral artery disease (PAD) are less compelling. Aspirin has modest evidence supporting a reduction in cardiovascular events in patients with PAD, whereas clopidogrel monotherapy may be more effective in PAD. Ticagrelor, a potent, reversibly binding P2Y12 receptor antagonist, is beneficial in patients with acute coronary syndrome and prior myocardial infarction. The EUCLID trial is designed to address the need for effective antiplatelet therapy in PAD to decrease the risk of cardiovascular events. STUDY DESIGN: EUCLID is a randomized, double-blind, parallel-group, multinational clinical trial designed to evaluate the efficacy and safety of ticagrelor compared with clopidogrel for the prevention of major adverse cardiovascular events in subjects with symptomatic PAD. Subjects with established PAD will be randomized in a 1:1 fashion to ticagrelor 90 mg twice daily or clopidogrel 75 mg daily. The primary end point is a composite of cardiovascular death, myocardial infarction, or ischemic stroke. Other end points address limb events including acute leg ischemia, need for revascularization, disease progression by ankle-brachial index, and quality of life. The primary safety objective is Thrombolysis in Myocardial Infarction-defined major bleeding. Recruitment began in December 2012 and was completed in March 2014; 13,887 patients were randomized. The trial will continue until at least 1,364 adjudicated primary end points occur. CONCLUSIONS: The EUCLID study is investigating whether treatment with ticagrelor versus clopidogrel, given as antiplatelet monotherapy, will reduce the incidence of cardiovascular and limb-specific events in patients with symptomatic PAD.

Evaluating cardiovascular event reduction with ezetimibe as an adjunct to simvastatin in 18,144 patients after acute coronary syndromes: final baseline characteristics of the IMPROVE-IT study population.

BACKGROUND: The IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) is evaluating the potential benefit for reduction in major cardiovascular (CV) events from the addition of ezetimibe versus placebo to 40 mg/d of simvastatin therapy in patients who present with acute coronary syndromes and have low-density lipoprotein cholesterol (LDL-C) ≤ 125 mg/dL. METHODS: The primary composite end point is CV death, nonfatal myocardial infarction (MI), nonfatal stroke, rehospitalization for unstable angina (UA), and coronary revascularization (≥ 30 days postrandomization). The simvastatin monotherapy arm's LDL-C target is <70 mg/dL. Ezetimibe was assumed to further lower LDL-C by 15 mg/dL and produce an estimated ~8% to 9% treatment effect. The targeted number of events is 5,250. RESULTS: We enrolled 18,144 patients with either ST-segment elevation MI (STEMI, n = 5,192) or UA/non-ST-segment elevation MI (UA/NSTEMI, n = 12,952) from October 2005 to July 2010. Western Europe (40%) and North America (38%) were the leading enrolling regions. The STEMI cohort was younger and had a higher percentage of patients naive to lipid-lowering treatment compared with the UA/NSTEMI cohort. The UA/NSTEMI group had a higher prevalence of diabetes, hypertension, and prior MI. Median LDL-C at entry was 100 mg/dL for STEMI and 93 mg/dL for UA/NSTEMI patients. CONCLUSIONS: This trial is evaluating LDL-C lowering beyond previously targeted LDL-C levels. The results depend on achieving the desired separation of LDL-C with ezetimibe and on the assumption that ezetimibe's lowering of LDL-C will have similar event reduction efficacy as the LDL-C lowering from a statin. The results could affect future therapies and guidelines.

Determinants of plasma vitamin D levels in patients with acute coronary syndromes.

BACKGROUND: Vitamin D is implicated in various biological functions ranging from cellular proliferation to immunity. Vitamin D deficiency is associated with an increased risk of several diseases including coronary atherosclerosis. MATERIALS AND METHODS: We measured plasma 25(OH)D3 level in 224 patients with acute coronary syndromes (ACS) and 209 control individuals by ELISA. We genotyped the study populations for 11 single nucleotide polymorphisms (SNPs) in seven genes involved in vitamin D biosynthesis and metabolism by 5' nuclease assays. RESULTS: The mean and median plasma 25(OH)D3 levels were not significantly different between patients with ACS and controls (median: 22·06 vs. 22·24 ng mL(-1) , respectively, P = 0·618). Plasma 25(OH)D3 level was < 20 ng mL(-1) in 175/433 (40%) and < 30 ng mL(-1) in 333/433 (77%) participants. Only four individuals had plasma 25(OH)D3 levels of above 60 ng mL(-1) . African-American and Hispanic populations, women and those with diabetes mellitus had significantly lower plasma 25(OH)D3 levels. In multivariable regression analysis, age, sex, diabetes mellitus, body weight, rs2762933 (CYP24A1) and rs6055987 (PLCB1) SNPs were independent predictors of plasma 25(OH)D3 level in the Caucasian population. CONCLUSIONS: We found no difference in mean plasma vitamin D levels between patients with ACS and controls. Differences in population characteristics between the two study groups including medications use and the lack of data on vitamin D, calcium and multivitamin supplements intake as well as the relatively small sample size of the populations could confound the results. Ethnic background, sex, age, body weight and SNPs in CYP24A1 and PLCB1 were independent determinants of plasma vitamin D levels.

Heparin-associated anti-Xa activity and platelet-derived prothrombotic and proinflammatory biomarkers in moderate to high-risk patients with acute coronary syndrome.

Heparin compounds, to include fractionated and unfractionated preparations, exert both antithrombotic and antiinflammatory effects through combined inhibition of factor Xa and thrombin. The contribution of modulated platelet activity in vivo is less clearly defined. The SYNERGY library was a prospectively designed repository for candidate clinical, hemostatic, platelet, and molecular biomarkers from patients participating in SYNERGY--a large-scale, randomized clinical trial evaluating the comparative benefits of unfractionated heparin (UFH) and enoxaparin in high-risk patients with acute coronary syndrome (ACS). Samples were collected from 201 patients enrolled at 26 experienced, participating sites and shipped to established core laboratories for analysis of platelet, endothelium-derived, inflammatory and coagulation activity biomarkers. Tissue factor pathway inhibitor (TFPI)--a vascular endothelial cell-derived factor Xa regulatory protein-correlated directly with plasma anti-Xa activity (unadjusted: r = 0.23, P < 0.0001; adjusted: ß = 0.10; P = 0.001), as did TFPI-fXa complexes (unadjusted: r = 0.34, P < 0.0001; adjusted: ß = 0.38; P = < 0.0001). In contrast, there was a direct and inverse relationship between anti-Xa activity and two platelet-derived biomarkers-plasminogen activator inhibitor-1 (unadjusted: r = -0.18, P = 0.0012; adjusted: ß = -0.10; P = 0.021) and soluble CD40 ligand (unadjusted: r = -0.11, P = 0.05; adjusted: ß = -0.13; P = 0.049). All measured analyte relationships persisted after adjustment for age, creatinine clearance, weight, sex, and duration of treatment. Differences in biomarkers between patients receiving UFH and those randomized to enoxaparin were not observed. The ability of heparin compounds to affect the prothrombotic and proinflammatory states which characterize ACS may involve factor Xa-related modulation of platelet activation and expression. Whether this potentially beneficial effect is direct or indirect and achieved, at least in part, through the release of endothelial cell-derived coagulation regulatory proteins will require further investigation.

Assessment of North American Clinical Research Site Performance During the Start-up of Large Cardiovascular Clinical Trials.

Importance: Randomized clinical trials (RCTs) are critical in advancing patient care, yet conducting such large-scale trials requires tremendous resources and coordination. Clinical site start-up performance metrics can provide insight into opportunities for improved trial efficiency but have not been well described. Objective: To measure the start-up time needed to reach prespecified milestones across sites in large cardiovascular RCTs in North America and to evaluate how these metrics vary by time and type of regulatory review process. Design, Setting, and Participants: This cohort study evaluated cardiovascular RCTs conducted from July 13, 2004, to February 1, 2017. The RCTs were coordinated by a single academic research organization, the Duke Clinical Research Institute. Nine consecutive trials with completed enrollment and publication of results in their target journal were studied. Data were analyzed from December 4, 2019, to January 11, 2021. Exposures: Year of trial enrollment initiation (2004-2007 vs 2008-2012) and use of a central vs local institutional review board (IRB). Main Outcomes and Measures: The primary outcome was the median start-up time (from study protocol delivery to first participant enrollment) as compared by trial year and type of IRB used. The median start-up time for the top 10% of sites was also reported. Secondary outcomes included time to site regulatory approval, time to contract execution, and time to site activation. Results: For the 9 RCTs included, the median site start-up time shortened only slightly over time from 267 days (interquartile range [IQR], 185-358 days) for 2004-2007 trials to 237 days (IQR, 162-343 days) for 2008-2012 trials (overall median, 255 days [IQR, 177-350 days]; P < .001). For the top 10% of sites, median start-up time was 107 days (IQR, 95-121 days) for 2004-2007 trials vs 104 days (IQR, 84-118 days) for 2008-2012 trials (overall median, 106 days [IQR, 90-120 days]; P = .04). The median start-up time was shorter among sites using a central IRB (199 days [IQR, 140-292 days]) than those using a local IRB (287 days [IQR, 205-390 days]; P < .001). Conclusions and Relevance: This cohort study of North American research sites in large cardiovascular RCTs found a duration of nearly 9 months from the time of study protocol delivery to the first participant enrollment; this metric was only slightly shortened during the study period but was reduced to less than 4 months for top-performing sites. These findings suggest that the use of central IRBs has the potential to improve RCT efficiency.