CORONARY ARTERY DISEASE TRIALS

10)CLARITY-TIMI 28 STUDY-The role of clopidogrel in early and sustained arterial patency after fibrinolysis for ST-segment elevation myocardial infarction: the ECG CLARITY-TIMI 28 Study.

Summary

OBJECTIVES: This study was designed to determine the relationship between clopidogrel and early ST-segment resolution (STRes) and the interaction of the two with clinical outcomes after fibrinolysis. BACKGROUND: ST-segment resolution is an early noninvasive marker of coronary reperfusion. METHODS: The CLARITY-TIMI 28 (Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis in Myocardial Infarction 28) trial randomized 3,491 patients with ST-segment elevation myocardial infarction (STEMI) undergoing fibrinolysis to clopidogrel versus placebo. ST-segment resolution was defined as complete (>70%), partial (30% to 70%), or none (<30%). RESULTS: Electrocardiograms were valid for interpretation in 2,431 patients at 90 min and 2,087 at 180 min. There was no difference in the rate of complete STRes between the clopidogrel and placebo groups at 90 min (38.4% vs. 36.6% at 90 min). When patients were stratified by STRes category, treatment with clopidogrel resulted in greater benefit among those with evidence of early STRes, with greater odds of an open artery at late angiography in patients with partial (odds ratio [OR] 1.4, p = 0.04) or complete (OR 2.0, p < 0.001) STRes, but no improvement in those with no STRes at 90 min (OR 0.89, p = 0.48) (p for interaction = 0.003). Clopidogrel was also associated with a significant reduction in the odds of an in-hospital death or myocardial infarction in patients who achieved partial (OR 0.30, p = 0.003) or complete STRes at 90 min (OR 0.49, p = 0.056), whereas clinical benefit was not apparent in patients who had no STRes (OR 0.98, p = 0.95) (p for interaction = 0.027). By 30 days, the clinical benefit of clopidogrel was predominately seen in patients with complete STRes. CONCLUSIONS: Clopidogrel appears to improve late coronary patency and clinical outcomes by preventing reocclusion of open arteries rather than by facilitating early reperfusion.

11)COMMIT trial- Addition of clopidogrel to aspirin in 45,852 patients with acute myocardial infarction: randomised placebo-controlled trial.

Summary

BACKGROUND: Despite improvements in the emergency treatment of myocardial infarction (MI), early mortality and morbidity remain high. The antiplatelet agent clopidogrel adds to the benefit of aspirin in acute coronary syndromes without ST-segment elevation, but its effects in patients with ST-elevation MI were unclear. METHODS: 45,852 patients admitted to 1250 hospitals within 24 h of suspected acute MI onset were randomly allocated clopidogrel 75 mg daily (n=22,961) or matching placebo (n=22,891) in addition to aspirin 162 mg daily. 93% had ST-segment elevation or bundle branch block, and 7% had ST-segment depression. Treatment was to continue until discharge or up to 4 weeks in hospital (mean 15 days in survivors) and 93% of patients completed it. The two prespecified co-primary outcomes were: (1) the composite of death, reinfarction, or stroke; and (2) death from any cause during the scheduled treatment period. Comparisons were by intention to treat, and used the log-rank method. This trial is registered with ClinicalTrials.gov, number NCT00222573. FINDINGS: Allocation to clopidogrel produced a highly significant 9% (95% CI 3-14) proportional reduction in death, reinfarction, or stroke (2121 [9.2%] clopidogrel vs 2310 [10.1%] placebo; p=0.002), corresponding to nine (SE 3) fewer events per 1000 patients treated for about 2 weeks. There was also a significant 7% (1-13) proportional reduction in any death (1726 [7.5%] vs 1845 [8.1%]; p=0.03). These effects on death, reinfarction, and stroke seemed consistent across a wide range of patients and independent of other treatments being used. Considering all fatal, transfused, or cerebral bleeds together, no significant excess risk was noted with clopidogrel, either overall (134 [0.58%] vs 125 [0.55%]; p=0.59), or in patients aged older than 70 years or in those given fibrinolytic therapy. INTERPRETATION: In a wide range of patients with acute MI, adding clopidogrel 75 mg daily to aspirin and other standard treatments (such as fibrinolytic therapy) safely reduces mortality and major vascular events in hospital, and should be considered routinely.

12) A randomized trial comparing clopidogrel versus ticlopidine therapy in patients undergoing infarct artery stenting for acute myocardial infarction with abciximab as adjunctive therapy.

Summary

AIM: To evaluate the impact of a clopidogrel therapy on the effectiveness of myocardial reperfusion in patients with ST-segment elevation acute myocardial infarction (AMI) undergoing routine infarct-related artery (IRA) stent implantation and receiving routine abciximab therapy. BACKGROUND: Inflammatory processes after mechanical restoration of flow in AMI play a central role in decreasing the effectiveness of reperfusion at microcirculatory level. Several studies suggest that clopidogrel may exert a protective effect against adverse cardiovascular events by virtue of its anti-inflammatory properties. METHODS: A total of 133 patients with a first ST-elevation AMI were randomized to clopidogrel (600-mg loading dose before IRA stenting followed by 75 mg daily, n = 66) or ticlopidine (500 mg before IRA stenting followed by 250 mg twice daily, n = 67). The primary end point was scintigraphic infarct size at 1 month. The secondary end points were ST-segment elevation resolution within 3 hours of procedure and 1-month clinical outcome, as a composite of death, reinfarction, target vessel revascularization, and stroke within 1 month of the index procedure. RESULTS: The 1-month technetium 99m sestamibi scintigraphy revealed similar infarct size (16.2% +/- 14.6% vs 15.0% +/- 14.1%, P = .703) and severity (0.48 +/- 0.18 vs 0.49 +/- 0.15, P = .592) in the clopidogrel group as compared with the ticlopidine group. Three-hour ST-segment resolution rate was similar in the 2 study groups (86% vs 89%, P = .642). At 1 month, there was no difference in major cardiovascular adverse event rate (3% vs 3%, P = .988). Discontinuation of thienopiridine therapy within the first month occurred in no patient randomized to clopidogrel and in 3 (4.5%) patients randomized to ticlopidine (P = .082). CONCLUSION: Clopidogrel has no impact on the effectiveness of myocardial reperfusion in patients with AMI treated routinely with stenting and abciximab. However, clopidogrel, administered as a 600-mg loading dose followed by 75 mg daily, is safe and at least as effective as the standard ticlopidine therapy in this subgroup of patients.

13)PCI-CLARITY: Effect of clopidogrel pretreatment before percutaneous coronary intervention in patients with ST-elevation myocardial infarction treated with fibrinolytics: the PCI-CLARITY study

Summary

CONTEXT: The benefit of clopidogrel pretreatment before percutaneous coronary intervention (PCI) remains debated and its use has not been universally adopted. OBJECTIVE: To determine if clopidogrel pretreatment before PCI in patients with recent ST-segment elevation myocardial infarction (STEMI) is superior to clopidogrel treatment initiated at the time of PCI in preventing major adverse cardiovascular events. DESIGN, SETTING, AND PARTICIPANTS: The PCI-Clopidogrel as Adjunctive Reperfusion Therapy (CLARITY) study was a prospectively planned analysis of the 1863 patients undergoing PCI after mandated angiography in CLARITY-Thrombolysis in Myocardial Infarction (TIMI) 28, a randomized, double-blind, placebo-controlled trial of clopidogrel in patients receiving fibrinolytics for STEMI. Patients were enrolled at 319 sites in 23 countries from February 2003 through October 2004. INTERVENTIONS: Patients received aspirin and were randomized to receive either clopidogrel (300 mg loading dose, then 75 mg once daily) or placebo initiated with fibrinolysis and given until coronary angiography, which was performed 2 to 8 days after initiation of the study drug. For patients undergoing coronary artery stenting, it was recommended that open-label clopidogrel (including a loading dose) be administered after the diagnostic angiogram. MAIN OUTCOME MEASURES: The primary outcome was the incidence of the composite of cardiovascular death, recurrent MI, or stroke from PCI to 30 days after randomization. Secondary outcomes included MI or stroke before PCI and the aforementioned composite from randomization to 30 days. RESULTS: Pretreatment with clopidogrel significantly reduced the incidence of cardiovascular death, MI, or stroke following PCI (34 [3.6%] vs 58 [6.2%]; adjusted odds ratio [OR], 0.54 [95% CI, 0.35-0.85]; P = .008). Pretreatment with clopidogrel also reduced the incidence of MI or stroke prior to PCI (37 [4.0%] vs 58 [6.2%]; OR, 0.62 [95% CI, 0.40-0.95]; P = .03). Overall, pretreatment with clopidogrel resulted in a highly significant reduction in cardiovascular death, MI, or stroke from randomization through 30 days (70 [7.5%] vs 112 [12.0%]; adjusted OR, 0.59 [95% CI, 0.43-0.81]; P = .001; number needed to treat = 23). There was no significant excess in the rates of TIMI major or minor bleeding (18 [2.0%] vs 17 [1.9%]; P>.99). CONCLUSIONS: Clopidogrel pretreatment significantly reduces the incidence of cardiovascular death or ischemic complications both before and after PCI and without a significant increase in major or minor bleeding. These data add further support to the early use of clopidogrel in STEMI and the strategy of routine clopidogrel pretreatment in patients undergoing PCI.

14) ExTRACT TIMI 25:Enoxaparin versus unfractionated heparin with fibrinolysis for ST-elevation myocardial infarction

Summary

BACKGROUND: Unfractionated heparin is often used as adjunctive therapy with fibrinolysis in patients with ST-elevation myocardial infarction. We compared a low-molecular-weight heparin, enoxaparin, with unfractionated heparin for this purpose. METHODS: We randomly assigned 20,506 patients with ST-elevation myocardial infarction who were scheduled to undergo fibrinolysis to receive enoxaparin throughout the index hospitalization or weight-based unfractionated heparin for at least 48 hours. The primary efficacy end point was death or nonfatal recurrent myocardial infarction through 30 days. RESULTS: The primary end point occurred in 12.0 percent of patients in the unfractionated heparin group and 9.9 percent of those in the enoxaparin group (17 percent reduction in relative risk, P<0.001). Nonfatal reinfarction occurred in 4.5 percent of the patients receiving unfractionated heparin and 3.0 percent of those receiving enoxaparin (33 percent reduction in relative risk, P<0.001); 7.5 percent of patients given unfractionated heparin died, as did 6.9 percent of those given enoxaparin (P=0.11). The composite of death, nonfatal reinfarction, or urgent revascularization occurred in 14.5 percent of patients given unfractionated heparin and 11.7 percent of those given enoxaparin (P<0.001); major bleeding occurred in 1.4 percent and 2.1 percent, respectively (P<0.001). The composite of death, nonfatal reinfarction, or nonfatal intracranial hemorrhage (a measure of net clinical benefit) occurred in 12.2 percent of patients given unfractionated heparin and 10.1 percent of those given enoxaparin (P<0.001). CONCLUSIONS: In patients receiving fibrinolysis for ST-elevation myocardial infarction, treatment with enoxaparin throughout the index hospitalization is superior to treatment with unfractionated heparin for 48 hours but is associated with an increase in major bleeding episodes. These findings should be interpreted in the context of net clinical benefit.

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