Aging and heparin-related bleeding

Background: Many studies have suggested that elderly patients are at increased risk of bleeding during heparin therapy. Objective: To establish whether the risk of bleeding in the elderly results from concomitant risk factors or is associated with the aging process itself. Methods: One hundred ninety-nine patients who presented with proximal deep vein thrombosis were treated with a standard intravenous heparin protocol in a double-blind, randomized, prospective study. Bleeding complications were monitored. Activated partial thromboplastin times and heparin levels were assessed 4 to 6 hours after a standard intravenous heparin bolus and infusion. Heparin doses and heparin levels were also assessed after stable therapeutic heparin infusion rates were established. Results: There was an increase in total and major bleeding complications with aging (P<.05) that was not accounted for by standard risk factors for bleeding. Aging was associated with an increase in heparin levels (r=.239, P=.003) and a tendency for an increase in activated partial thromboplastin time (r=.134, P=.07) after standard heparin doses. Aging was also associated with lower heparin dose requirements (r=-.267, P=.003) after therapeutic activated partial thromboplastin times were achieved. Conclusion: Aging is a risk for heparin-related bleeding that may be explicable by age-related changes in the pharmacologic characteristics of heparin.