Comparison of Heparin Therapy for ≤48 Hours to >48 Hours in Unstable Angina Pectoris

Of 450 consecutive patients with unstable angina admitted to a tertiary care, university-based medical center over a 24-month period, 334 were administered heparin and aspirin for some length of time. Two groups of 98 patients matched for acuity and gender at baseline were treated with either ≤48 hours (group 1) or >48 hours (group 2) of heparin. The acuity model used in this study incorporates 6 factors: age, recent myocardial infarction, treatment with intravenous nitroglycerin, previous therapy with β blockers or calcium antagonists, baseline ST depression, and diabetes. Despite similar risks and overall clinical outcome, group 2 had significantly more myocardial infarction or death after 48 hours than group 1 (p = 0.01). In part, this was due to a delay in the performance of coronary angiography (2.8 ± 1.4 vs 3.5 ± 15 days, p = 0.01), coronary intervention (2.7 ± 1.8 vs 5.1 ± 2.3 days, p = 0.01), and bypass surgery (3.8 ± 3.6 vs 7.0 ± 5.6 days, p = 0.02). There was no difference between groups regarding the success of coronary intervention (90% vs 88%, p = NS). Heparin duration was influenced by the finding of intracoronary thrombus or ulceration on angiography before revascularization, as each finding was seen more often in group 2 (thrombus, 12% vs 24%; ulceration, 38% vs 60%). These results suggest that the optimal duration of heparin therapy is up to 48 hours after admission in unstable angina; a longer time period is associated with increased adverse consequences. rospectively designed, matched case trial compares clinical outcome in patients with unstable angina treated with heparin and aspirin ≤48 hours and >48 hours. Results demonstrate that the optimal duration of therapy is up to 48 hours, as a longer time period is associated with increased risk of complications.