PROSPECTIVE, RANDOMIZED, PLACEBO-CONTROLLED, DOUBLE-BLIND, MULTICENTER STUDY OF EXERCISE WITH ENOXAPARIN PRETREATMENT FOR STABLE-EFFORT ANGINA

In this double-blind, placebo-controlled, multicenter trial, we examin ed the combined effects of repeated exercise and intravenous enoxapari n (low-molecular-weight heparin) on treadmill exercise capacity and an giographic collateral growth and compared them with the effect of repe ated exercise with placebo. Fifty-two patients with stable-effort angi na were randomly assigned to receive one of two doses of enoxaparin (4 0 or 60 mg) or placebo. In each patient, 20 treadmill exercise session s were performed with the pretreatment of enoxaparin or placebo for 2 to 3 weeks. Before and after treatment, coronary cineangiography was r epeated to evaluate the changes in coronary and collateral circulation . Improvement of rate-pressure product (RPP) at the onset of angina wa s taken as an index of enhanced collateral flow reserve. Although the mean differences in the magnitude of increase in RPP were not signific antly different between the 3 groups, a heterogeneous response was obs erved: 1620 beats/min . mm Hg in 40 mg (p = 0.12), 3060 beats/min . mm Hg in 60 mg (p = 0.02), and 1090 beats/min . mm Hg in placebo (p = 0. 44). The end-points of the exercise test were changed from chest disco mfort to leg fatigue or dyspnea in 10 (28%) of 36 enoxaparin-treated p atients but in only 1 (6%) of 16 placebo patients (p = value not signi ficant (NS)). Similarly, the extent of coronary and collateral circula tion to the completely obstructed coronary artery was increased in 17 (47%) of 36 enoxaparin-treated patients but only in 4 (25%) of 16 plac ebo patients (p = NS). In this short-term study in patients with chron ic-effort angina, treatment with a combination of exercise and enoxapa rin resulted in a statistically significant improvement in treadmill e xercise capacity, presumably as a result of the growth of collaterals to the jeopardized myocardium.