History and Objectives: Due to prevalence of cardiovascular diseases particularly unstable angina pectoris and its known and controllable prognosis and considering the present controversies about the route of administration of heparin, this study was performed on patients with unstable angina pectoris referred to Shaheed Beheshti hospital in Kashan in 1374 to compare the effects of subcutaneous versus intravenous administration of heparin.

Materials and Methods: A clinical trial was performed on 100 patients in 2 groups of subcutaneous versus intravenous heparin administration. Patients, selected by random and matching, were divided into 2 experimental (Subcutaneous) and control (Intravenous) groups. The effects on number of pain attacks, occult ischemia and complications such as mortality, myocardial infarction and severe bleeding in a minimum of 5 days follow-up were evaluated and statistical analysis was performed by X² test.

Results: This study was performed on 50 patients in 2 experimental and age, sex and risk factors (Hypertension, diabetes, hyperlipidemia and cigarette smoking) matched control group. Pain attacks in the different days following treatment were similar in both groups, 15.6% and 14% in intravenous and subcutaneous groups respectively. Occult ischemia was less commonly observed in the subcutaneous heparin group than intravenous one, but the difference was not statistically meaningful. There was no mortality. 2 patients had myocardial infarction in each group and one had severe hemorrhage in the intravenous group.

Conclusion: subcutaneous heparin has therapeutic effects similar to intravenous heparin. Further studies especially complemented by angiography and scan are recommended.