Low-molecular-weight heparin alone versus a combination of unfractionated heparin and low-molecular-weight heparin.

OBJECTIVES

We analyzed the effect of the pharmacologic combination of 2 indirect antithrombin drugs--enoxaparin (low-molecular-weight heparin) and unfractionated heparin--versus enoxaparin alone on the recurrence of ischemia.

BACKGROUND

Blocking some key factors of the coagulation cascade supports the concept that an antithrombin effect is needed during the acute phase of ischemia.

METHODS

This was a prospective, randomized, pilot trial in patients with an acute coronary ischemic event occurring within the previous 24 hours. A total of 126 patients were allocated to receive aspirin (200 mg/day orally) plus 1 mg/kg subcutaneous enoxaparin at 8 AM and 12.500 IU of subcutaneous unfractionated heparin at 8 PM (group A) or subcutaneous enoxaparin 1 mg/kg (group B).

RESULTS

Severe recurrent ischemia provoking urgent coronary revascularization occurred in 12 patients (9.5%), 3 (5%) in group A and 9 (13%) in group B (P = .1). Refractory angina was present in 27 patients (21%), 10 (17%) in group A and 17 (25%) in group B (P = .45). The combination of severe recurrent ischemia and refractory angina occurred in 23% of group A, and 37% of group B (odds ratio 0.49; 95% confidence intervals, 0.21-1.15; P = .07). A total of 7 patients (5%) had acute nonfatal myocardial infarction develop, 3 (5%) in group A and 4 (6%) in group B. Two (1.6%) deaths were observed in the study, both in group B. The incidence of the double end point (death plus nonfatal myocardial infarction) was 5% in group A versus 9% in group B (P = .5) and the triple end point (death, nonfatal myocardial infarction, and severe recurrent ischemia) was 10.5% in group A vs 22% in group B (odds ratio 0.42, 95% confidence intervals, 0.13-1.29; P = .09).

CONCLUSIONS

The combination of 2 indirect antithrombin drugs capable of intermittently blocking the coagulation system is not associated with a significant loss of safety.