Enoxaparin Restenosis (ERA) Trial. - ERA


ERA was a randomized, placebo-controlled, double-blind trial designed to evaluate whether enoxaparin given subcutaneously daily for 28 days after successful angioplasty would be associated with a reduction in restenosis.

Study Design

Study Design:

Patients Enrolled: 457

Patient Populations:

Age ≥21 years and had successful angioplasty performed.


Patients were excluded if they met one of the following criteria: woman of childbearing potential, history of bleeding disorders or recent active bleeding, uncontrolled asthma or hypertension (blood pressure >180/105 mm Hg), active peptic ulcer disease, history of heparin-associated thrombocytopenia, acute MI within 5 days, abrupt vessel closure after angioplasty, or other complications requiring heparin therapy for >24 hours after percutaneous transluminal coronary angioplasty (PTCA), a left main artery stenosis of >50%, angioplasty of a saphenous vein graft, or prior PTCA at the same site.

Primary Endpoints:

Loss of 50% of the initial gain in lumen diameter achieved at angioplasty or clinical evidence of restenosis. In the absence of angioplasty, clinical evidence of restenosis was defined as death, myocardial infarction, repeat revascularization, or worsening angina.

Secondary Endpoints:

Other angiographic categorical definitions of restenosis as well as the change in minimal lumen diameter were also analyzed. Additional efficacy assessment included the presence of >0.1 mV of ST-segment depression and exercise duration on the exercise stress test and clinical events including worsening angina, death, myocardial infarction, bypass surgery, and angioplasty.

Drug/Procedures Used:

Patients meeting qualifying criteria were randomized to receive either placebo or Enoxaparin (40 mg SC daily for 28 days) after a successful procedure. The drug was begun 2 hours after femoral sheath removal and was administered no later than 24 hours after the procedure. Patients returned at 1, 4, and 24 weeks after angioplasty for clinical and bleeding assessment. Laboratory assessment measured at each time point included complete blood count, coagulation profile, and liver function tests. A treadmill exercise test using the modified Bruce protocol was obtained before and at 1 and 24 weeks after randomization. All patients returned for repeat coronary angiography 24 weeks after randomization.

Concomitant Medications:

Heparin was administered during the PTCA procedure. Aspirin (325 mg) was administered 1 day before and throughout the treatment period.

Principal Findings:

The "all-treated" patient group included all patients who received at least one dose of the study medication (n=231 for placebo and n=227 for enoxaparin). The "evaluable" patient group included all treated patients who also had angiography performed at 26+-12 weeks after randomization or earlier if warranted by recurrence of angina or clinical symptoms and had study medication administered within 36 hours of successful PTCA and had received a minimum of 22 doses (n=176 for placebo and n=181 for enoxaparin). Treatment failure, defined as a loss of 50% of the gain in lumen diameter achieved at angioplasty or clinical evidence of restenosis, occurred in 51% of placebo patients and 52% ofEnoxaparin patients in the all-treated group (P=0.625). In the evaluable patient group, restenosis occurred in 49% of the placebo group and 50% of the Enoxaparin group (odds ratio, 1.04; P=NS). The acute gain in MLD was 1.10 mm for the placebo group and 1.15 mm for the Enoxaparin group. The late loss in lumen diameter was 0.49 mm and 0.54 mm, respectively (P=0.78). The cumulative distribution of the minimal lumen diameter before PTCA, immediately after PTCA, and at follow-up similarly showed no differences between groups. Asymptomatic angiographic restenosis occurred in 29% of the placebo group and 27% of the Enoxaparin group. Comparison of the 109 patients in the placebo group and the 106 patients in the Enoxaparin group in whom adequate paired exercise tests were obtained showed no differences in anginal ST-segment changes. The overall incidence of major and minor bleeding was 34% in the placebo group and 48% in the Enoxaparin group (P<0.0008). This difference primarily was confined to minor bleeding episodes.


Among patients undergoing successful angioplasty, the ERA trial demonstrated that Enoxaparin, a low molecular weight heparin, given for 28 days after angioplasty was not associated with a reduction in the incidence of restenosis or of adverse clinical outcomes when compared with placebo. Furthermore, enoxaparin was associated with an increase in bleeding complications, although most of the bleeding was defined as minor.


Faxon DP, et al. Angioplasty/Artherectomy/Stents (Cardiac and Peripheral): Low Molecular Weight Heparin in Prevention of Restenosis After Angioplasty: Results of Enoxaparin Restenosis (ERA) Trial. Circulation 1994;90(2):908-914

Clinical Topics: Anticoagulation Management, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Blood Cell Count, Liver Function Tests, Treatment Failure, Coronary Angiography, Enoxaparin, Coronary Disease, Angioplasty, Balloon, Coronary, Exercise Test

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