Frequency of major hemorrhage in patients treated with unfractionated intravenous heparin for deep venous thrombosis or pulmonary embolism - A study in routine clinical practice

Background: The rate of major hemorrhage during the initial treatment with, unfractionated heparin (UFH) in patients with deep venous thrombosis (DVT) and pulmonary embolism (PE) in routine clinical practice is understudied. In recent clinical trials an overall average of 3.8% was reported. However, the incidence of this complication in routine patient care might be higher owing to less strict patient selection and lack of standardization in the administration of heparin. We have determined major bleeding rates during h eparin treatment for DVT or PE in routine practice and compared these rates with data from clinical trials. Methods: Data on the occurrence of major hemorrhage were retrieved accordin g to strict criteria from the records of patients who had received continuo us intravenous UFH therapy to treat objectively documented DVT or PE in 3 h ospitals. Results: After exclusion of 29 patients because of lack of objective diagno sis of DVT or PE and 25 patients because of initial treatment with low-mole cular-weight heparin, 424 consecutive patients were available for detailed analysis. Among them, 17 patients (4.0%; 95% confidence interval, 2.1%-5.9% ) experienced major hemorrhage during UFH treatment, which in most patients occurred at the end of planned heparin therapy; one of the hemorrhages was fatal. Six patients (1.4%; 95% confidence interval, 0.3%-2.5%) developed c linically suspected recurrent venous thromboembolism (fatal in 1 case) duri ng UFH treatment or within 7 days' cessation. Conclusions: Administration of continuous intravenous UFH in patients with DVT or PE in routine clinical practice leads to a major bleeding rate of 4. 0%. This rate is comparable to the rate of major bleeding in patients who r eceived UFH in clinical trials. Our findings are relevant to the discussion of major bleeding rates in patients with DVT and PE treated in daily clini cal practice with subcutaneous low-molecular-weight heparin and newer antit hrombotic drugs.