1.   This practice is based largely on the belief that intravenous heparin increases coronary artery patency rates.

2.   In fact, the two trials that directly compared intravenous heparin with no heparin as adjunctive therapy to thrombolysis in the absence of aspirin give contradictory results.

3.   Furthermore, patency studies provide inconsistent evidence of efficacy, and no trial has shown a benefit of intravenous heparin over aspirin in adequate doses.

4.   For tPA, intravenous heparin added to aspirin seems to provide a small additional patency benefit.

5.   Sobel and Collen suggested that clinical decisions on intravenous heparin should await the outcome of unfinished trials.

6.   At present, the only available data on the addition of intravenous heparin to full-dose aspirin plus thrombolysis are from non-randomised comparisons.