High Dose Heparin as Pretreatment for Primary Angioplasty in Acute Myocardial Infarction: The Heparin in Early Patency (HEAP) Trial - HEAP


HEAP was an open-label, randomized trial of high dose heparin versus low dose heparin for patients with acute myocardial infarction (AMI) scheduled to undergo primary angioplasty.


High dose heparin will achieve lysis of coronary thrombi and improve early patency of the infarct related vessel.

Study Design

Study Design:

Patients Enrolled: 584
Mean Follow Up: Hospital discharge
Mean Patient Age: <75
Female: 21

Patient Populations:

Patients with ST segment elevation myocardial infarction (>/=2mm in two or more contiguous leads) presenting within 6 hours of symptom onset, or within 24 hours if they had evidence of ongoing ischemia.


Age > 75, contraindication to heparin, recent MI.

Primary Endpoints:

TIMI flow grade at angioplasty.

Secondary Endpoints:

Enzymatic infarct size, LVEF, Bleeding, Death.

Drug/Procedures Used:

Before primary angioplasty, patients with ST elevation myocardial infarction were randomized to either high dose heparin (300 IU/kg) or low dose heparin (0 or 5000 IU). The low dose group received 5000 U of heparin if they were transferred from an outside facility for catheterization, and no heparin if they presented directly to the primary angioplasty center.

Concomitant Medications:

All patients received aspirin and nitroglycerine. Thrombolytics and glycoprotein IIB/IIIA inhibitors were not allowed.

Principal Findings:

A total of 585 patients were enrolled (299 high dose arm, 285 low dose arm). The groups were well matched at baseline in terms of age, gender, infarct location by ECG, and comorbid conditions. In the low dose arm, 74 patients received 5000 U of heparin and 212 received no heparin. 278 patients (93%) in the high dose arm and 266 patients (93%) in the low dose arm underwent primary angioplasty.

Rates of TIMI grade 2 or 3 flow were similar between arms at angiography (22% vs. 21%, p>0.1). TIMI 3 flow was observed in 13% of the high dose arm and 8% of the low dose arm (p=0.11). Success rate for angioplasty, enzymatic infarct size, LVEF, major bleeding, and death rates were similar between arms.


Among patients with acute ST segment elevation myocardial infarction undergoing primary angioplasty, administration of high dose heparin was not associated with improved early patency or clinical outcomes compared to low dose heparin.


Liem A, Zijlstra F, Ottervanger J, Hoorntje J, Suryapranta H, Boer M, Verheugt F. High Dose Heparin as Pretreatment for Primary Angioplasty in Acute Myocardial Infarction: The Heparin in Early Patency (HEAP) Trial. J Am Coll Cardiol 2000;35:600-4.

Clinical Topics: Anticoagulation Management, Invasive Cardiovascular Angiography and Intervention

Keywords: Myocardial Infarction, Catheterization, Heparin, Electrocardiography, Angioplasty, Balloon, Coronary

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