Cardiology Trials Cardiology Trials

N Engl J Med 2019;381:1524-1534
Background Dual antiplatelet therapy after percutaneous coronary intervention had become a standard of care. Both prasugrel and ticagrelor had been shown to provide more rapid and consistent platelet inhibition than clopidogrel. Randomized controlled trials had shown both drugs were superior to clopidogrel in patients with acute coronary syndromes.
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The two drugs have different loading strategies in patients who have acute coronary syndromes without ST-segment elevation. In these patients, ticagrelor is usually administered as pretreatment before diagnostic angiography, but prasugrel is administered only after the coronary anatomy has been assessed by means of diagnostic angiography since no advantage has been observed when prasugrel is used as pretreatment.
Before ISAR-REACT 5, there had been no direct comparisons of the two antiplatelet drugs. ISAR-REACT 5 was an investigator-initiated multicenter, non-industry funded RCT to compare the efficacy and safety of the two treatments in patients with acute coronary syndrome.
Patients The trial enrolled 4013 patients from 23 centers. Patients were eligible with either STEMI, NSTEMI or unstable angina for which intervention was planned. Exclusion criteria included intolerance of either drugs, history of stroke or intracranial bleeding or any condition that increased the risk of bleeding. Patients could not be on concomitant oral or i.v. therapy with drugs affecting CYP3A4 system.
Baseline Characteristics There were 2012 patients assigned to ticagrelor and 2006 patients assigned to prasugrel. The suspected diagnosis at admission was STEMI in 41%, NSTEMI in 46%, and unstable angina in 13% of the patients. The average age was 64 years. Female sex was 24%. Average systolic blood pressure and heart rate was 144 mmHg and 77 bpm. All factors were well balanced.
Trial Procedures Therapy with ticagrelor was started at a loading dose of 180 mg and continued at a maintenance dose of 90 mg twice daily. Patients who were assigned to ticagrelor received the loading dose as soon as possible after randomization. Therapy with prasugrel was started at a loading dose of 60 mg and continued at a maintenance dose of 10 mg once per day. A reduced maintenance dose of 5 mg daily was recommended in patients who were 75 years of age or older and in those who had a body weight of less than 60 kg.
Prasugrel therapy turned on presentation. STEMI patients were given prasugrel as soon as possible after randomization. In those without STEMI, the loading dose was delayed until knowledge of the coronary anatomy. Prasugrel loading was given before crossing the lesion. In patients with a coronary angiography–confirmed acute coronary syndrome who were not considered to be candidates for PCI but who were considered to be candidates for conservative therapy, dual antiplatelet therapy (aspirin and the randomly assigned trial medication) was recommended.
About 83% of patients received PCI, 2% CABG and 13-14% were managed conservatively. Clinical follow-up was scheduled at 30 days, 6 and 12 months.
Endpoints The primary end point was a composite of death, MI, or stroke at 1 year after randomization. Secondary end points included the safety end point, which was the incidence of bleeding at 1 year (type 3, 4, or 5 on the Bleeding Academic Research Consortium [BARC] scale, which ranges from 0 to 5, with higher values indicating more severe bleeding), the incidence of the individual components of the primary end point at 1 year, and the incidence of definite or probable stent thrombosis at 1 year.
The sample-size calculation assumed a primary endpoint would occur in 10% in the ticagrelor group vs 12.9% in the prasugrel group. This led to an estimate of 1900 patients in each group and 80% power to detect a relative risk reduction of 22%

N Engl J Med 2013;369:999-1010
Background: Adding P2Y12 inhibitors to aspirin improves outcomes in patients with acute coronary syndrome. Yet, debate persisted regarding the optimal timing for administering these drugs in patients undergoing percutaneous coronary intervention (PCI). The ATLANTIC trial showed that pre-hospital administration of ticagrelor did not improve outcomes compared to in-hospital administration, in patients with ST elevation myocardial infarction.
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The ACCOAST trial sought to test the hypothesis that administering the P2Y12 inhibitor, prasugrel, 2-48 hours before angiography in non-ST elevation myocardial infarction patients is superior to administering it during PCI.
Patients: Patients were enrolled if they had non-ST elevation myocardial infarction. Patients were scheduled to undergo angiography with possible PCI within 2-48 hours after randomization. Patients were excluded if they had cardiogenic shock, refractory ventricular arrhythmias, prior hemorrhagic or ischemic stroke or TIA, history of intracranial neoplasms, history of intracranial AV malformations or aneurysm, surgery within 4 weeks, active bleeding or history of bleeding diathesis or had high risk of bleeding based on the judgement of the investigator.
Baseline characteristics: The average age of patients was 64 years with 72% being men. The average weight was 82 kg. About 20% had diabetes, 45% had hyperlipidemia, 62% had hypertension and 33% were current smokers. Creatinine clearance was ≤ 30 ml/min in 3% of the patients and GRACE score was After randomization, 68.7% of the patients underwent PCI while 25.1% were treated medically. CABG within 7 days was performed in 6.2% of the patients.
Procedures: Patients were randomized 1:1 to receive pretreatment with prasugrel or matching placebo (control group). Those in the pretreatment group received a 30 mg loading dose of prasugrel before coronary angiography with an additional 30 mg if angiography confirmed the need for PCI. Patients in the control group received placebo before coronary angiography and a 60 mg loading dose of prasugrel in patients undergoing PCI. Only the initial 30 mg loading dose of prasugrel or placebo were administered, if a decision, after coronary angiography, was made to pursue CABG or medical therapy.
Endpoints: The primary efficacy end point was a composite endpoint of death from cardiovascular causes, myocardial infarction, stroke, urgent revascularization, or the need for rescue therapy with glycoprotein IIb/IIIa inhibitors. Follow up for the primary endpoint was 7 days post randomization. Secondary endpoints included death from any cause, stent thrombosis and a composite endpoint of death from cardiovascular causes, myocardial infarction, or stroke.
Safety end points were major or minor bleeding according to Thrombolysis in Myocardial Infarction (TIMI) criteria.
Statistical analysis was performed on the intention-to-treat principle. To achieve 80% power with two-sided alpha of 0.05 for detecting 24% relative risk reduction in the pretreatment compared to the control group, 400 patients with the primary outcome and approximately 4,100 enrolled patients would be needed.
Results: The trial randomized 2,037 patients to the pre-treatment group and 1,996 to the control group. The median time from the initial loading dose to PCI was 4.3 hours.
The incidence of the composite primary end point was similar between both treatment groups (10.0% in the pre-treatment group vs 9.8% in the control group, HR: 1.02, 95% CI: 0.84 – 1.25; p= 0.81). There was no significant difference between both treatment groups in any of the components of the primary end point, death from any cause, or stent thrombosis. Results were similar for patients who underwent PCI (about two thirds of study participants).
There were more major bleeding

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N Engl J Med 2014;371:1016-1027
Background: Prior trials have demonstrated that combining P2Y12 inhibitors with aspirin in patients with acute coronary syndrome reduces cardiovascular events. Prasugrel, in the TRITON-TIMI 38 trial, and ticagrelor, in the PLATO trial, were administered in the hospital.
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Older trials had suggested that early administration of glycoprotein IIb/IIIa inhibitors improves outcomes in patients with ST elevation myocardial infarction (STEMI).
The ATLANTIC trial sought to test the hypothesis that pre-hospital compared to in-hospital administration of the P2Y12 inhibitor, ticagrelor, improves outcomes in patients with STEMI.
Patients: Patients were enrolled if they had STEMI and had experienced symptoms for at least 30 minutes but no longer than 6 hours, and were expected to have EKG to balloon inflation of less than 120 minutes. Patients were excluded if they had prior intracranial bleeding, moderate to severe liver disease, gastrointestinal bleeding within 6 months, planned fibrinolytic therapy or required dialysis.
Baseline characteristics: The average age of patients was 61 years with 80% being men. The average weight was 80 kg. About 14% had diabetes, 9% had prior myocardial infarction, 4% had chronic obstructive pulmonary disease and 2% had chronic renal failure. TIMI risk score was 0-2 in 61% of the patients. About 90% had Killip class I. Coronary angiography was performed in 98% of the patients and percutaneous coronary intervention (PCI) with stent placement was performed in 82%. The use of glycoprotein IIb/IIIa inhibitors was high in the study and was administered before percutaneous coronary intervention in 29% of the patients.
Procedures: Patients were randomized 1:1 to receive ticagrelor en route to the hospital/ catheterization lab (group 1) or at the catheterization lab (group 2). In group 1, patients received ticagrelor 180mg en route to the hospital and placebo in the catheterization lab. In group 2, patients received placebo en route to the hospital and ticagrelor 180mg in the catheterization lab. Following that, all patients received ticagrelor 90mg twice daily for at least 30 days and the treatment was recommended to continue for 12 months. Clinical endpoints were adjudicated up to 30-days post randomization.
Endpoints: There were two coprimary endpoints – proportion of patients who did not have 70% or greater resolution in their ST-segment elevation before PCI and proportion of patients without TIMI grade III flow in the infarcted artery before PCI. Review of EKG and angiographic data was blinded.
A secondary prespecified endpoint included the composite of all-cause death, myocardial infarction, stent thrombosis, stroke or urgent revascularization at 30 days.
Analysis was performed based on the modified intention-to-treat principle, defined as patients who received at least one loading dose of the study drug. Patients with missing EKG or angiographic data were excluded from the primary endpoint analysis.
The sample size estimate was based on an anticipated event rate of 15% in the control group for the EKG endpoint. They estimated that 779 patients would be needed in each group to show a 6% absolute difference with 80% power and an alpha of 2.5%.
Results: The trial randomized 1,862 patients, 909 patients to the prehospital group and 953 to the in-hospital group. The median time from randomization to angiography was 48 minutes and the median time between the two loading doses was 31 minutes.
There was no significant difference in the proportion of patients who did not have 70% or more ST segment resolution before PCI (86.8% for the pre-hospital group vs 87.6% for the in-hospital group, OR: 0.93, 95% CI: 0.69 – 1.25; p= 0.63) or the proportion of patients who did not have TIMI III flow in the infarcted artery before PCI (82

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JAMA. 2013;309(12):1241-1250
Background Case reports as early as the 1950s suggested chelation of lead might reduce angina. The popularity of chelation accelerated around the turn of the century. Small underpowered trials of chelation were inconclusive. Mainstream medicine considered chelation unproven and potentially hazardous.
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Chelation with disodium EDTA binds divalent and some trivalent cations, including calcium, magnesium, lead, cadmium, zinc, iron, aluminum, and copper, which facilitates their urinary excretion. High dose vitamins are often co-administered with chelation.
The NIH-funded Trial to Assess Chelation Therapy (TACT) trial was conducted to respond to the public health problem posed by EDTA chelation therapy: namely, that large numbers of patients could be exposed to undefined risks for unproven benefits. TACT was a double-blind placebo-controlled 2x2 factorial randomized trial enrolling 1708 patients to test chelation therapy.
Patients Eligibility for TACT required patients be older than 50 years, have a creatinine of 160/100 mm Hg, past intolerance to the chelation or vitamin components, chelation therapy within 5 years, coronary or carotid revascularization planned or having taken place within 6 months, cigarette smoking within 3 months, active heart failure or heart failure hospitalization within 6 months, or inability to tolerate 500-mL infusions weekly. Enrollment began in 2003 and follow-up continued until 2011. There were 134 sites; 60% of which were established chelation centers.
Baseline Characteristics The median age of patients was 65 years, 18% were women and the median body mass index was 30. More than 90% of patients had had either percutaneous coronary intervention or coronary bypass surgery. Approximately 31% of patients had diabetes. Use of guideline directed medications was typical of a well-treated population of post-MI patients. Procedures The active 10-component chelation solution consisted of up to 3 g of disodium EDTA; 7 g of ascorbic acid; 2 g of magnesium chloride; 100 mg of procaine; 2500 U of unfractionated heparin; 2 mEq of potassium chloride; 840 mg of sodium bicarbonate; 250 mg of pantothenic acid; 100 mg of thiamine; 100 mg of pyridoxine; and sterile water to make up 500 mL of solution. The identical-appearing placebo solution consisted of 500 mL of normal saline and 1.2% dextrose (2.5 g total).
The chelation or placebo infusions were administered through a peripheral intravenous line, weekly for the first 30 infusions, followed by an additional 10 infusions 2 to 8 weeks apart.
Patient also received an oral vitamin-mineral regimen vs an oral placebo.
In this review, we focus on the intention-to-treat comparison of EDTA chelation vs placebo.Endpoints The primary endpoint was a composite of death, reinfarction, stroke, coronary revascularization, or hospitalization for angina.
TACT trialists had planned to enroll 2300 patients over three years with a follow-up of one year. Enrollment was slow, and with permission from the data safety monitoring board (DSMB) enrollment was decreased to 1700 patients and follow-up was extended. The resultant power was 85% to detect a 25% reduction in the primary endpoint assuming a 2.5% per year event rate in the placebo arm.
Over the course of the trial, the DSMB requested 11 interim analyses of the data. Because of the increased monitoring, the level of statistical significance required for the primary endpoint was enhanced to a P value of less than 0.036.
Results After a median follow-up of 55 months, a primary end point occurred in 222 (26%) of the chelation group and 261 (30%) of the placebo group (hazard ratio [HR]: 0.82 [95% CI: 0.69-0.99]; p= .035). There was no effect on total mortality (10% vs 11%, HR: 0.93, 95% CI: 0.70-1.25; p= 0.64). Myocardial infarction and coronary revascul