RANDOMIZED COMPARISON OF SUBCUTANEOUS HEPARIN, INTRAVENOUS HEPARIN, AND ASPIRIN IN UNSTABLE ANGINA

Intravenous heparin has been used in the control of myocardial ischaem ia in patients with unstable angina. We set out to assess the efficacy of subcutaneous heparin in reducing myocardial ischaemia in patients with unstable angina. 343 of 399 patients with unstable angina were mo nitored for 24 h and 108 were refractory to conventional antianginal t reatment and were entered into a randomised multicentre trial. 37 pati ents were assigned to heparin infusion (partial thromboplastin time 1. 5-2 times baseline), 35 to subcutaneous heparin (adjusted dose with pa rtial thromboplastin time 1.5-2 times baseline), and 36 to aspirin (32 5 mg daily). All had additional conventional antianginal therapy. Afte r the run-in patients were monitored for 3 days. The primary endpoint was reduced myocardial ischaemia assessed by the number of anginal att acks, silent ischaemic episodes, and duration:of ischaemia per day. At 1 week and 1 month we accounted for anginal attacks and other clinica l events (myocardial infarction, revascularisation procedures, and dea th). Aspirin did not significantly affect the incidence of myocardial ischaemia. On the first 3 days, infused and subcutaneous heparin signi ficantly decreased the frequency of angina (on average by 91% and 86%, respectively), episodes of silent ischaemia (by 56% and 46%), acid th e overall duration of ischaemia (66% and 61%) versus run-in day and as pirin (p<0.001 for all variables). The favourable effects of heparin t herapy remained evident during follow-up. Only minor bleeding complica tions occurred. Subcutaneous heparin is effective in the control of my ocardial ischaemia in patients with unstable angina.