Atrial fibrillation and mortality among patients with acute coronary syndromes without ST-segment elevation: results from the PURSUIT trial.
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BACKGROUND: In the setting of percutaneous coronary revascularization, agents in the class known as platelet glycoprotein IIb/IIIa inhibitors have significantly reduced the incidence of death or nonfatal myocardial infarction at 30 days. We assessed whether there are differences in safety or efficacy between two such inhibitors, tirofiban and abciximab. METHODS: Using a double-blind, double-dummy design at 149 hospitals in 18 countries, we randomly assigned patients to receive either tirofiban or abciximab before undergoing percutaneous coronary revascularization with the intent to perform stenting. The primary end point was a composite of death, nonfatal myocardial infarction, or urgent target-vessel revascularization at 30 days. The trial was designed and statistically powered to demonstrate the noninferiority of tirofiban as compared with abciximab. RESULTS: The primary end point occurred more frequently among the 2398 patients in the tirofiban group than among the 2411 patients in the abciximab group (7.6 percent vs. 6.0 percent; hazard ratio, 1.26; one-sided 95 percent confidence interval of 1.51, demonstrating lack of equivalence, and two-sided 95 percent confidence interval of 1.01 to 1.57, demonstrating the superiority of abciximab over tirofiban; P=0.038). The magnitude and the direction of the effect were similar for each component of the composite end point (hazard ratio for death, 1.21; hazard ratio for myocardial infarction, 1.27; and hazard ratio for urgent target-vessel revascularization, 1.26), and the difference in the incidence of myocardial infarction between the tirofiban group and the abciximab group was significant (6.9 percent and 5.4 percent, respectively; P=0.04). The relative benefit of abciximab was consistent regardless of age, sex, the presence or absence of diabetes, or the presence or absence of pretreatment with clopidogrel. There were no significant differences in the rates of major bleeding complications or transfusions, but tirofiban was associated with a lower rate of minor bleeding episodes and thrombocytopenia. CONCLUSIONS: Although the trial was intended to assess the noninferiority of tirofiban as compared with abciximab, the findings demonstrated that tirofiban offered less protection from major ischemic events than did abciximab.
BACKGROUND: Troponin T (TnT) is valuable for short- and long-term risk stratification of patients with acute coronary syndromes (ACS). It also may predict which ACS patients will benefit from glycoprotein (GP) IIb/IIIa blockade. METHODS AND RESULTS: We prospectively studied 1160 patients with non-ST-segment elevation ACS randomized in PARAGON-B to receive lamifiban, an intravenous GP IIb/IIIa antagonist, or placebo. TnT levels were obtained before study treatment began and 24 to 72 hours later; assays were performed by a blinded core laboratory. At baseline, 40.2% of patients were TnT-positive (>/=0.1 ng/mL); these patients were older and more often male or smokers. Patients positive at baseline had a significantly higher rate of the primary end point (composite of death, myocardial [re]infarction, or severe recurrent ischemia at 30 days; odds ratio, 1.5; 95% CI, 1.1 to 2.1) than those who were TnT-negative. Lamifiban was associated with significant reduction in the primary end point (from 19.4% to 11.0%, P=0.01) among TnT-positive patients but not among TnT-negative patients (11.2% for placebo versus 10.8% for lamifiban, P=0.86; P=0.08 for test of interaction between TnT status and treatment assignment). This pattern held for the end points of death alone and death or myocardial (re)infarction at 30 days. Peak TnT level at 48 hours did not differ with lamifiban treatment. CONCLUSIONS: TnT predicts poor short-term outcomes in non-ST-segment elevation ACS. Treatment benefit with lamifiban is limited almost exclusively to TnT-positive patients, reducing 30-day adverse outcomes to a rate nearly identical to that of negative patients.
BACKGROUND: Plasminogen activator therapy for acute myocardial infarction is limited by lack of achievement of early, complete, and sustained reperfusion in a substantial proportion of patients. Many phase II trials have supported the potential of combined fibrinolytic therapy and platelet glycoprotein IIb/IIIa inhibition for improving reperfusion. We did a randomised, open-label trial to compare the effect of reteplase alone with reteplase plus abciximab in patients with acute myocardial infarction. METHODS: 16588 patients in the first 6 h of evolving ST-segment elevation myocardial infarction were randomly assigned standard-dose reteplase (n=8260) or half-dose reteplase and full-dose abciximab (n=8328). The primary endpoint was 30-day mortality, and secondary endpoints included various complications of myocardial infarction. Analysis was by intention to treat. FINDINGS: At 30 days, 488 (5.9%) of patients in the reteplase group had died, compared with 468 (5.6%) in the combined reteplase and abciximab group (odds ratio 0.95 [95% CI 0.83-1.08], p=0.43). There were fewer deaths or non-fatal reinfarctions with the combination than with reteplase alone, and there was less need for urgent revascularisation and fewer major non-fatal ischaemic complications of acute myocardial infarction. On the other hand, there were more non-intracranial bleeding complications in the combination group. The rates of intracranial haemorrhage and non-fatal disabling stroke were similar. INTERPRETATION: Although combined reteplase and abciximab was not superior to standard reteplase, the 0.3% absolute (5% relative) decrease in 30-day mortality fulfilled the criteria of non-inferiority. Combination therapy led to a consistent reduction in key secondary complications of myocardial infarction including reinfarction, which was partly counterbalanced by increased non-intracranial bleeding complications.
OBJECTIVES: The goal of this study was to test: 1) if platelet glycoprotein IIb/IIIa (GP IIb/IIIa) blockade with abciximab bolus plus 12-h infusion reduces mortality after percutaneous coronary intervention (PCI); 2) if prevention of early myocardial infarction (MI) after PCI is a mechanism for reducing mortality; and 3) for risk factors for mortality after PCI. BACKGROUND: Studies of PCI suggest that MI after intervention is predictive of mortality. Abciximab, a platelet GP IIb/IIIa receptor inhibitor, has consistently reduced the incidence of MI among PCI patients in several trials. The presumed mechanism is prevention of platelet thrombus associated with vessel wall injury and downstream embolization into the microcirculation. METHODS: In eight trials, 5,154 patients were randomized to a regimen comprising conventional therapy plus a bolus of abciximab within 1 h before PCI followed by a 12-h infusion; 4,136 controls were randomized to conventional therapy alone. Patient follow-up from six months to three years was available. Survival differences are examined using proportional hazards regression and survival curves. RESULTS: A hazard ratio of 0.71 (95% confidence interval 0.57 to 0.89; p = 0.003) suggests a mortality benefit with abciximab. The absolute reduction in mortality was estimated to be 0.5% through 30 days, 0.7% through six months, 0.9% through one year and 1.8% through three years. Early MI explained 18% of the observed mortality benefit at one year. Multivariate regression suggests that patients with advanced cardiovascular disease may derive the greatest mortality benefit from abciximab. CONCLUSIONS: The evidence from 9,290 randomized PCI patients shows a mortality benefit provided by abciximab bolus plus 12-h infusion.
BACKGROUND: Lipid-lowering agents are known to reduce long-term mortality in patients with stable coronary disease or significant risk factors. However, the effect of lipid-lowering therapy on short-term mortality immediately after an acute coronary syndrome has not been determined. We did an observational study using data from two randomised trials to investigate this issue. METHODS: We used data from the GUSTO IIb and PURSUIT trials to compare all-cause mortality among patients with acute coronary syndromes who were discharged on lipid-lowering agents (n=3653) with those who were not (n=17,156). A propensity analysis was done to adjust for presumed selection biases in the prescription of lipid-lowering agents. FINDINGS: Lipid-lowering therapy was associated with a smaller proportion of deaths at 30 days (17 [0.5%] vs 179 [1.0%], hazard ratio 0.44 [95% CI 0.27-0.73], p=0.001) and at 6 months (63 [1.7%] vs 605 [3.5%], 0.48 [0.37-0.63], p<0.0001). After adjustment for the propensity to be prescribed lipid-lowering agents and other potential confounders, prescription of a lipid-lowering agent at discharge remained associated with a reduced risk of death at 6 months (0.67 [0.48-0.95], p=0.023). INTERPRETATION: Prescription of a lipid-lowering drug at hospital discharge was independently associated with reduced short-term mortality among patients after an acute coronary syndrome.
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OBJECTIVES: We sought to determine the incidence of and risk factors for thrombotic events early after discontinuing antithrombin therapy in patients with acute coronary syndromes. BACKGROUND: Discontinuation of treatment with heparin and other thrombin inhibitors in patients with unstable coronary syndromes has related to clinical and biochemical evidence of early reactivation of thrombosis. METHODS: We studied 8,943 of the 12,142 patients with acute coronary syndromes enrolled in the Global Use of Strategies To Open occluded arteries in acute coronary syndromes trial of hirudin versus heparin. We excluded patients who received no study drug, lacked timing data, died or had myocardial (re)infarction [(re)MI] during study-drug infusion, or began heparin treatment within 2 h after treatment with the study drug was stopped. We assessed the incidence and timing of (re)MI by type and timing of antithrombin treatment. RESULTS: In all, 215 patients (2.4%) suffered (re)MI, 49 within 12 h of antithrombin therapy discontinuation and 166 between hour 12 and hospital discharge. The duration of infusion did not differ between the hirudin and heparin groups. The rate of early re(MI) after drug therapy discontinuation was significantly higher in patients given heparin versus hirudin (0.8% vs. 0.3%, p = 0.002). Patients with (re)MI had higher mortality at 30 days (23.6% vs. 2.4%, p = 0.001) and 1 year (35.2% vs. 6.7%, p = 0.001) compared with patients without (re)MI. CONCLUSIONS: The incidence of (re)MI was clustered within 12 h of heparin therapy discontinuation, with the greatest risk within 4 h. There was no evidence of early reactivation of thrombotic events after hirudin. Patients who had (re)infarction had worse outcomes. Better understanding of the mechanism and possible prevention of recurrent thrombosis is needed.
BACKGROUND: Platelet inhibition at the time of a percutaneous coronary intervention has consistently been shown to decrease the risk of thrombotic adverse events but not restenosis. The role of enhanced antiplatelet protection through pretreatment with the platelet ADP-receptor antagonist ticlopidine in preventing both the early and late complications of coronary stenting has not previously been explored. METHODS AND RESULTS: In the Evaluation of Platelet IIb/IIIa Inhibitor for Stenting (EPISTENT) trial, approximately 1600 patients were randomized to stenting with either placebo or abciximab in addition to aspirin and heparin. All stented patients also received ticlopidine after the procedure, but 58% of these patients were given ticlopidine before stenting at the discretion of the investigating physician. Among patients randomized to placebo, ticlopidine pretreatment was associated with a significant decrease in the incidence of the composite end point of death, myocardial infarction, or target vessel revascularization (TVR) at 1 year (adjusted hazard ratio, 0.73; 95% CI, 0.54 to 0.98; P:=0.036). Ticlopidine pretreatment did not significantly influence the risk of death or myocardial infarction in patients randomized to abciximab. Controlling for patient characteristics and for the propensity of being on ticlopidine, Cox proportional hazards regression identified ticlopidine pretreatment as an independent predictor of the need for TVR at 1 year (hazard ratio, 0.62; 95% CI, 0.43 to 0.89; P:=0.010) in both placebo-treated and abciximab-treated patients. CONCLUSIONS: In the EPISTENT trial, among patients randomized to stenting, starting ticlopidine before the percutaneous coronary intervention was associated with a significant decrease in the incidence of the 12-month composite end point for patients not receiving abciximab and the need for TVR among all patients.
Platelet glycoprotein IIb/IIIa inhibitors have been extensively studied in the treatment of patients with ischemic heart disease. Data regarding the use of these agents in the absence of concomitant intravenous heparin have been conflicting. We sought to determine, using propensity analysis, whether the benefit of eptifibatide, a IIb/IIIa inhibitor, in the treatment of acute coronary syndromes is affected by the concurrent administration of heparin. By trial design, patients were randomized to either eptifibatide or placebo, whereas use of intravenous heparin was left to the discretion of treating physicians. The effect of eptifibatide on the 30-day composite end point of death or myocardial infarction was studied in patients who received heparin and those who did not. Propensity analysis methods were used to control for confounding and presumed selection biases. Among 5,576 patients who were receiving heparin when the bolus dose of the study drug was administered, eptifibatide was associated with a reduced composite end point rate (13%) compared with that of placebo (14.5% vs 16.6%, p = 0.03). In contrast, among 1,441 patients who were not receiving heparin, there was no difference in 30-day event rates with eptifibatide compared with placebo (13.7% vs 13.1%, p > 0.7). After a propensity score for use of heparin was developed, however, use of heparin did not affect the reduced risk associated with eptifibatide (adjusted relative risk [RR] for heparin-eptifibatide interaction term 0.90, 95% confidence interval [CI] 0.61 to 1.32, p > 0.5), but the propensity for heparin use was a strong predictor of events (adjusted RR 1.76, 95% CI 1.42 to 2.17, p < 0.001). The use of eptifibatide independently predicted a lower risk of events (adjusted RR 0.31, 95% CI 0.10 to 0.93, p = 0.04). Thus, the apparent positive impact of heparin on the benefits of eptifibatide therapy was largely due to confounding and bias.
BACKGROUND: Early reinfarction after thrombolytic therapy is associated with adverse outcomes and increased mortality. Among patients with reinfarction in the 1992 Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO I) and the 1998 Assessment of the Safety of a New Thrombolytic (ASSENT 2) trials, we investigated temporal and regional differences in the use of repeat thrombolysis, revascularization (angioplasty and/or bypass surgery), or conservative measures and the outcomes of each management strategy. METHODS AND RESULTS: Data from the 4% of patients (n=2301) who experienced reinfarction after thrombolytic therapy were studied. Baseline characteristics, 30-day mortality, and incidence of total and hemorrhagic strokes were compared among the 3 treatment groups. The 30-day mortality did not differ between the repeat thrombolysis and revascularization groups (P=0.72), and it was significantly lower among patients treated by these 2 strategies than in those treated conservatively (11% and 11% versus 28%, respectively; P<0.001). Stroke rates did not differ significantly between the 3 treatment strategies (P=0.49). From 1992 to 1998, the percentage of reinfarction patients treated with repeat thrombolysis decreased from 29.3% to 18.5% in US centers and from 51.4% to 41.9% in all other centers (P<0.001). In contrast, use of revascularization procedures increased from 33.5% to 47.9% in US centers and from 8.1% to 23.0% in all other centers (P<0.001). CONCLUSIONS: Repeat thrombolysis and revascularization are associated with significantly lower mortality among reinfarction patients. Randomized trials are necessary to assess the exact risks and benefits of rethrombolysis versus interventional revascularization in this subset of high-risk patients presenting with reinfarction after thrombolytic therapy.
BACKGROUND: Unfractionated heparin has been the primary anticoagulant therapy for percutaneous coronary intervention for >20 years. Despite the availability of rapid "point of care" testing, little clinical data defining the optimal level of anticoagulation are available. Furthermore, recent reports have advocated the use of low-dose heparin regimens in the absence of large-scale, well-conducted studies to support this practice. METHODS AND RESULTS: We pooled the data from 6 randomized, controlled trials of novel adjunctive antithrombotic regimens for percutaneous coronary interventions in which unfractionated heparin constituted the control arm. Patients were divided into 25-s intervals of activated clotting times (ACTs), from <275 s to >476 s. In a total of 5216 patients, the incidence of death, myocardial infarction, or any revascularization and major or minor bleeding at 7 days were calculated for each group and compared. An ACT in the range of 350 to 375 s provided the lowest composite ischemic event rate of 6.6%, or a 34% relative risk reduction in 7-day ischemic events compared with rates observed between 171 and 295 s by quartile analysis (P=0.001). CONCLUSIONS: Contrary to recent reports, the optimal suppression of ischemic events with unfractionated heparin therapy in patients undergoing percutaneous coronary intervention demands treatment to ACT levels that are substantially higher than currently appreciated. These data define a goal for heparin dosing within coronary interventions and establish a benchmark of optimal unfractionated heparin therapy against which future trials of novel antithrombotic regimens in percutaneous interventions can be compared.
BACKGROUND: After coronary artery bypass surgery, patients have a high cumulative rate of graft closure and recurrent ischemic events. We sought to determine whether antiplatelet therapy with clopidogrel would be more effective than aspirin, the accepted standard, in these patients. METHODS AND RESULTS: The event rates for all-cause mortality, vascular death, myocardial infarction, stroke, and rehospitalization were determined for the 1480 patients with a history of cardiac surgery randomized to either clopidogrel or aspirin in a trial of 19 185 patients. The event rate per year of vascular death, myocardial infarction, stroke, or rehospitalization was 22.3% in the 705 patients randomized to aspirin and 15.9% in the 775 patients randomized to clopidogrel (P:=0.001). A risk reduction was also seen in each of the individual end points examined, including a 42.8% relative risk reduction in vascular death in patients on clopidogrel versus aspirin (P:=0.030). In a multivariate model incorporating baseline clinical characteristics, clopidogrel therapy was independently associated with a decrease in vascular death, myocardial infarction, stroke, or rehospitalization in patients with a history of cardiac surgery, with a 31.2% relative risk reduction (95% CI, 15.8 to 43.8; P:=0.0003). Although clopidogrel therapy was efficacious in the entire Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) population, multivariate analysis demonstrated that patients with previous cardiac surgery derived particular benefit (P:=0.015). CONCLUSION: Compared with aspirin, clopidogrel therapy results in a striking reduction in the elevated risk for recurrent ischemic events seen in patients with a history of prior cardiac surgery, along with a decreased risk of bleeding.
BACKGROUND: Numerous clinical trials have established the benefits of intravenous glycoprotein IIb/IIIa inhibition in the management of coronary artery disease. In contrast, the recent large-scale, placebo-controlled, randomized trials of the oral glycoprotein IIb/IIIa antagonists have failed to provide commensurate reductions in late composite ischemic end points despite potent inhibition of platelet aggregation. METHODS AND RESULTS: The ORs for death, myocardial infarction, urgent revascularization, and major bleeding from the 4 large-scale, placebo-controlled, randomized trials with oral glycoprotein IIb/IIIa inhibitors were calculated and combined. Stratification by low-dose or high-dose therapy and the use of concurrent aspirin was also undertaken. In 33 326 patients followed for >30 days, a consistent and statistically significant increase in mortality was observed with oral glycoprotein IIb/IIIa therapy (OR, 1.37; 95% CI, 1.13 to 1.66; P:=0.001). This effect was evident regardless of aspirin coadministration and treatment with either low-dose or high-dose therapy. Although a reduction in urgent revascularization was observed with oral glycoprotein IIb/IIIa inhibition, pooled analysis favored an increase in myocardial infarction that did not demonstrate statistical significance. CONCLUSIONS: Although we found a highly significant excess in mortality consistent across 4 trials with 3 different oral glycoprotein IIb/IIIa inhibitor agents, this was associated with a reduction in the need for urgent revascularization and no increase in myocardial infarction. These findings suggest the potential for a direct toxic effect with these agents and argue against a prothrombotic mechanism. Further investigation to elucidate the cause of this increased fatality risk is warranted.
OBJECTIVES: We aimed to evaluate the benefits of the glycoprotein (GP) IIb/IIIa antagonist, eptifibatide, after patients with acute coronary syndromes (ACS) were admitted to hospitals that approach revascularization for ACS through early transfer to tertiary referral centers. BACKGROUND: Across a variety of hospital settings, GP IIb/IIIa inhibition, after patients were admitted to the hospital for non-ST segment elevation ACS, is associated with a reduction in death or myocardial infarction (MI) before and during a percutaneous coronary intervention. METHODS: The outcomes of 429 patients from 153 sites in the Platelet glycoprotein IIb/IIIa in unstable angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) trial, who were transferred during study drug infusion ("transfer patients"), were compared with those of 1,987 patients who either remained in the hospital at those sites or were transferred after study drug termination ("nontransfer patients"). RESULTS: The baseline characteristics of transfer and nontransfer patients were similar. Patients receiving eptifibatide were transferred less frequently than those receiving placebo (16% vs. 20%, p = 0.014). Transfer patients underwent more procedures and experienced a greater 30-day incidence of death or MI, as compared with nontransfer patients (21% vs. 12%, p = 0.001). Eptifibatide was associated with a reduction in death or MI through 30 days, independent of transfer status (2.5% absolute reduction), as well as for those transferred (5.5% absolute reduction). CONCLUSIONS: For patients with ACS admitted to community hospitals, eptifibatide is associated with a reduced need for transfer and improved clinical outcomes.
OBJECTIVES: Our objectives were to develop a risk-stratification model addressing the importance of the magnitude and distribution of ST segment depression in predicting long-term outcomes and to validate the model in an analogous patient population. BACKGROUND: Although patients without ST segment elevation presenting with acute coronary syndromes represent an increasingly frequent population admitted to coronary care units, little attention has been paid to quantifying their ST segment abnormalities. METHODS: ST segment depression was categorized into three groups: 1) no ST segment depression; 2) 1-mm ST segment depression in two contiguous leads; and 3) ST segment depression > or =2 mm in two contiguous leads. A logistic regression model was developed using Platelet IIb/IIIa Antagonism for the Reduction of Acute coronary syndrome events in a Global Organization Network (PARAGON-A) data to assess the prognostic value of the extent and distribution of ST segment depression in predicting one-year mortality. The model was validated using the non-ST segment elevation population in Global Use of Strategies To Open occluded arteries in acute coronary syndromes (GUSTO-IIb). RESULTS: ST segment depression was the strongest predictor of one-year mortality, accounting for 35% of the model's predictive power. Patients with ST segment depression > or =2 mm were approximately 6 times (odds ratio [OR] 5.73, 95% confidence interval [CI] 2.8 to 11.6) more likely to die within one year than patients with no ST segment depression. On validation, the model showed good discriminatory power (c-index = 0.75). Patients with ST segment depression > or =2 mm in more than one region were almost 10 times more likely to die within one year than patients with no ST segment depression. CONCLUSIONS: These data provide new evidence supporting the powerful prognostic value of the baseline electrocardiogram and, in particular, the magnitude and distribution of ST segment depression in predicting unfavorable events.
OBJECTIVES: The role of P-selectin in the process of restenosis was evaluated using a recombinant immunoglobulin (Ig) chimera form of its ligand, soluble P-selectin glycoprotein ligand-Ig (rPSGL-Ig), as a competitive inhibitor for the natural ligand on leukocytes. BACKGROUND: Inflammation and coagulation activation after vascular injury may be an important factor in the development of restenosis. P-selectin has been shown to mediate leukocyte-endothelium and leukocyte-platelet interaction. These interactions are mediated through binding of P-selectin to P-selectin glycoprotein ligand-1 (PSGL-1) located on the surface of leukocytes. METHODS: Balloon injury was induced in the left anterior descending and right coronary arteries of 16 pigs at a balloon/artery diameter ratio of 1.5:1. Either rPSGL-Ig (1 mg/kg) or saline was randomly administered 15 min before balloon injury as an intravenous bolus. Four weeks after injury, morphometric analysis, immunohistochemistry and histological evaluation were performed on injured arterial segments. RESULTS: Increased luminal area was found in the rPSGL-Ig group compared with the placebo group (1.63 +/- 0.57 mm2 vs. 1.26 +/- 0.32 mm2, p = 0.044) owing to significantly reduced neointimal hyperplasia (cross-sectional area, 0.46 +/- 0.45 mm2 vs. 0.13 +/- 0.11 mm2, p = 0.013). Immunohistochemistry and histological evaluation showed a significant decrease in the presence of tumor necrosis factor-alpha, interleukin-1 beta, and infiltration of macrophages in the injured vessel segments in the rPSGL-Ig group. CONCLUSIONS: P-selectin antagonism using rPSGL-Ig decreases neointimal hyperplasia following balloon injury, by inhibiting the inflammatory and thrombotic responses at the site of balloon injury, which appears to play a pivotal role in the pathogenesis of restenosis.