Hemorrhagic complications of intravenous heparin use.

To document the incidence of bleeding complications occurring in patients admitted to a cardiology service treated with intravenous heparin and to identify the major risk factors for these adverse events. Intravenous heparin is effective treatment for a variety of cardiologic conditions but is associated with a number of adverse effects, including hemorrhage. During the study, 1,253 consecutive patients were admitted for acute cardiac care and of these, 416 were treated with intravenous heparin. A total of 39 complications occurred in 37 heparin-treated patients (8.9%), of which 23 were hemorrhagic complications occurring in 21 heparin-treated patients (5.5%). Of these hemorrhagic complications, 12 were directly related to a vascular access site and 11 were apparently "spontaneous" hemorrhages. There was no apparent relation between the dose (mean 1,021 U/hour [range 531 to 1,882]) or duration (6.7 +/- 5.7 days) of heparin therapy and hemorrhagic complications. In a multivariate analysis, female gender (odds ratio [OR] 4.76 [14.39 to 1.56]; p = 0.006), recent thrombolytic therapy (OR 12.9 [4.1 to 40.6]; p <0.0001), and a reduced admission hemoglobin (OR 1.41 [0.52 to 0.97]; p = 0.031) were significantly predictive of a hemorrhagic event. The incidence of cardiac catheterization procedures was not significantly higher in the complication group (OR 3.9 [0.84 to 18.4]; p = 0.082). Aspirin therapy, admission platelet count, and weight were noncontributory. Hemorrhagic complications occurred in 5.5% of patients receiving a continuous infusion of heparin. The use of thrombolytic therapy, female gender (independent of weight), and a reduced admission hemoglobin were significant independent predictors of hemorrhagic events.