Safety of Outpatient Treatment In Acute Pulmonary Embolism.

Systematic reviews have shown that subcutaneous low molecular weight heparins (LMWH) are at least as safe and effective in the treatment of venous thromboembolism (VTE) as intravenous unfractionated heparin (UFH). LMWH allows patients with VTE to be treated as outpatients. However, patients with pulmonary embolism (PE) are still systematically admitted to the hospital for a few days to avoid potential complications. Physicians are reluctant to discharge patients due to insufficient data supporting the safety of outpatient management of PE. This study evaluates the safety of outpatient treatment of acute PE at the Ottawa Hospital.

This is a retrospective cohort study of consecutive patients presenting at the Ottawa Hospital with acute PE diagnosed between January 1, 2007 and December 31, 2008. PE was defined as an arterial filling defect on CTPA or a high probability V/Q scan. Patients diagnosed with PE during hospitalization, patients with chronic PE and patients in whom anticoagulation treatment was not initiated (e.g. palliative care patients, small clinical non-significant PE) were excluded from the analyses. Patients were managed as outpatients if they were hemodynamically stable, did not require supplemental oxygenation and did not have contraindications to low molecular weight heparin therapy.

In this cohort of 473 patients with acute PE, 260 (55.0%) were treated as outpatients and 213 (45.0%) were admitted to the hospital. The majority of the patients were admitted because of severe comorbidities (45.5%) or hypoxia (22.1%).No outpatient died of fatal PE during the 3 month follow-up period. At the end of follow-up, the overall mortality was 5.0% (95% CI: 2.7 to 8.4%). The rates of recurrent venous thromboembolism (VTE) in the outpatient group were 0.4% (95% CI: 0.0 to 2.1%) and 3.8% (95% CI: 1.9 to 7.0%) within 14 days and 3 months, respectively. The rates of major bleeding episodes were 0% (95% CI: 0 to 1.4%) and 1.5% (95% CI: 0.4 to 3.9%) within 14 days and 3 months, respectively. Four (1.5%) outpatients were admitted to hospital within the first 14 days because of progressive shortness of breath and pain, a pre-syncopal episode or heparin induced thrombocytopenia.

A majority of patients with acute PE can be managed as outpatients with a low risk of mortality, recurrent VTE and major bleeding episodes. Outpatient treatment in PE is feasible and safe in uncomplicated patients.

Rodger:Pfizer: Research Funding; Leo Pharma: Research Funding; Sanofi Aventis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Canadian Institutes of Health Research: Research Funding; Heart and Stroke Foundation: Research Funding.