Acute pulmonary embolism during warfarin therapy and long-term risk of recurrent fatal pulmonary embolism

John Paul Moutzouris; Austin Chin Chwan Ng; Vincent Chow; Tommy Chung; Jennifer Curnow; Leonard Kritharides

doi:10.1160/TH13-04-0288

Thrombosis and Haemostasis, Table of Contents

Thromb Haemost 2013; 110(03): 523-533
DOI: 10.1160/TH13-04-0288

Blood Coagulation, Fibrinolysis and Cellular Haemostasis

Schattauer GmbH

Acute pulmonary embolism during warfarin therapy and long-term risk of recurrent fatal pulmonary embolism

Authors

John Paul Moutzouris

¹Cardiology Department, Concord Hospital, The University of Sydney, Hospital Road, Concord, New South Wales, Australia
Austin Chin Chwan Ng

¹Cardiology Department, Concord Hospital, The University of Sydney, Hospital Road, Concord, New South Wales, Australia
Vincent Chow

¹Cardiology Department, Concord Hospital, The University of Sydney, Hospital Road, Concord, New South Wales, Australia
Tommy Chung

¹Cardiology Department, Concord Hospital, The University of Sydney, Hospital Road, Concord, New South Wales, Australia
Jennifer Curnow

²Haematology Department, Concord Hospital, The University of Sydney, Hospital Road, Concord, New South Wales, Australia
Leonard Kritharides

¹Cardiology Department, Concord Hospital, The University of Sydney, Hospital Road, Concord, New South Wales, Australia

Abstract

Summary

The clinical characteristics and long-term outcomes of patients presenting with acute pulmonary embolism (PE) during treatment with warfarin have not been described. Clinical details of all patients admitted to a tertiary institution from 2000-2007 with acute PE were retrieved retrospectively, baseline warfarin status and the international normalised ratio (INR) were recorded, and their outcomes tracked using a statewide death registry. Of 923 patients with clearly documented warfarin status included in this study, 83 (9%) were taking warfarin. Mean (± standard deviation) day-1 INR of those taking warfarin was 2.3 ± 0.9, with 67% of patients therapeutically anti-coagulated (INR ≥2.0) at presentation (49 patients with INR <2.5 and 34 with INR ≥2.5). Patients taking warfarin on admission were more likely to have heart failure, atrial fibrillation and valvular heart disease, with similar prevalence of malignancy and ischaemic heart disease, compared to patients not on warfarin. Total mortality of the cohort (mean follow-up 4.0 ± 2.5 years) was 31.6% (in-hospital mortality 1.5%), and was similar between warfarin and no warfarin groups. There was however a greater than four-fold increased risk of post-discharge death due to recurrent PE for the patients taking warfarin on admission (hazard ratio [HR] 4.43, 95% confidence interval [CI] 1.36-14.42, p=0.01). Among patients taking warfarin on admission, day-1 INR <2.5 significantly increased long-term all-cause mortality compared to INR ≥2.5 (adjusted HR 2.51, 95% CI 1.08-5.86, p=0.03). In conclusion, patients presenting with PE during treatment with warfarin have an increased risk of death from recurrent PE. Admission INR appears to have independent long-term prognostic importance in these patients.

Keywords

Pulmonary embolism - anticoagulation - warfarin - international normalized ratio

Full Text

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