Characteristics of Patients with Pulmonary Embolism Requiring High Doses of Intravenous Heparin

Objective: ­­­­­Anticoagulation is the cornerstone of treatment of pulmonary embolism (PE). The treatment of intermediate risk patients is not clear and there is wide inter-individual variability in the dose of heparin needed to attain effective anticoagulation. In this study we assessed the baseline characteristics and outcomes of patients requiring high doses of unfractioned heparin (UFH).

Patients and methods: 106 patients admitted to Sheba Medical Center Cardiac Intensive Care Unit with intermediate risk PE were enrolled into the study. Patients’ baseline data, therapy, hospital course and outcomes were abstracted from the patients’ electronic charts. Patients were then stratified into 2 groups by the UFH dose required to achieve therapeutic anticoagulation as assessed by the activated prothrombin time (aPTT) and compared. A second stratification was conducted by time needed to achieve anti-coagulant therapeutic threshold.

Results: Patients receiving higher doses of UFH were significantly younger (by 10 years on average) and were markedly less overweight (by 5 BMI points). They also had longer times to therapeutic anticoagulation threshold, were less likely to be within the anticoagulant therapeutic window and had longer hospital stays. No significant differences in in-hospital outcomes or long-term mortality were noted.

Conclusion: Patients with intermediate-risk PE treated with weight-adjusted UFH have favourable outcomes. We did not find any association between UFH dose needed to achieve therapeutic anticoagulation and the development of in-hospital adverse events or long-term mortality.

Keywords: Pulmonary Embolism, venous thromboembolism, anti-coagulation, unfractioned heparin, obesity.