Early discharge and home supervision of patients with pulmonary embolism treated with low-molecular weight heparin

Abstract

Background: The objective of the study is to determine the efficacy, safety and feasibility of home treatment with low-molecular weight heparin (LMWH) in patients with symptomatic pulmonary embolism (PE). Methods: All patients with PE on the home treatment programme between January 1998 and December 1999 were identified. Age, sex, length of hospital stay, risk factors for PE, ventilation perfusion (V/Q) lung scanning results, baseline investigations and treatment regimen were recorded. PE was defined as a clinical diagnosis supported by a high, intermediate or low probability V/Q lung scan. The efficacy of the treatment is defined as the event rate of recurrent PE. The safety outcome is defined as the rate of haemorrhage and the mortality that was related to the treatment during the 6-month follow-up period. Results: Seventy patients were identified. Of these, 68 were hospitalised initially with a mean±S.D. length of hospital stay of 4.0±3.3 (range 0–17) days; their mean±S.D. age was 54.6±20.5 (range 19–87) years. Cardiopulmonary disease was the commonest pre-existing condition and 86% patients had at least one risk factor. All except one was haemodynamically stable. During the 6 months after discharge, 20 patients (28.6%) were readmitted at least once. One patient (1.4%) had symptomatic recurrent PE, one (1.4%) had haemoptysis and the remainder had unrelated pathology. There were no episodes of serious haemorrhage, and the two deaths that occurred in this period were not due to further PE. Conclusion: Early discharge home for stable patients with PE treated with LMWH (tinzaparin) is feasible, effective and safe, provided that patients are clinically stable, accessible by phone, receive daily administration of LMWH and have their international normalised ratio (INR) monitored.

Introduction

Pulmonary emboli are responsible for approximately 10% of all hospital deaths [1]. Recent studies have shown that the incidence of pulmonary embolism (PE) is 69 per 100 000 [2], [3] and commonly occurs in patients presenting to hospital [2], [3], [4], [5]. The standard treatment for PE has been initial treatment with dose-adjusted, continuous, intravenous unfractionated heparin, followed by warfarin anticoagulant therapy, with initial treatment and monitoring being in hospital.

Low-molecular weight heparins (LMWH) are an important new class of antithrombotic agents. They differ from unfractionated heparin in having greater bioavailabilty, a longer plasma half-life and a higher ratio of anti-factor Xa to anti-factor IIa activity. They are also less likely to induce haemorrhage and give a more predictable anticoagulant response [6], [7], [8]. They are administered as a single subcutaneous injection and have a lower incidence of heparin-induced thrombocytopenia than unfractionated heparin [9]. Although LMWH are more expensive than unfractionated ones, once daily administration and the absence of the need for dosage adjustment has been shown to reduce the cost of care [10]. Out-patient treatment of patients with PE using LMWH has the potential to reduce health costs, but it is unclear if most PE can be treated safely and effectively in this less supervised environment.

The efficacy and safety of LMWH for the treatment of deep vein thrombosis (DVT) and PE are well established [11], [12], [13], [14]. In most studies of out-patient treatment of DVT, patients with symptomatic PE were excluded [15], [16], [17]. Little is known about the efficacy, safety and feasibility of home treatment with LMWH in patients with symptomatic PE. We therefore conducted a retrospective study of the use of LMWH for patients with PE managed at home.