Clot Burden and Comorbidity in Natural History of Untreated Pulmonary Thromboembolism-To the Editor

Abstract

Dr. Iles is correct: the mortality of untreated pulmonary embolism (PE) in the small (but only) randomized clinical trial reported by Barritt and Jordan 1 Barritt DW Jordan SC Anticoagulant drugs in the treatment of pulmonary embolism: a controlled trial. Lancet. 1960; 1: 1309-1312 Abstract PubMed Scopus (1080) Google Scholar was five deaths among 19 patients (26%), not 38% as shown in Table 1 in my article. 2 Dalen JE Pulmonary embolism: what have we learned since Virchow? Treatment and prevention. Chest. 2002; 122: 1801-1817 Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar I apologize for this error. Their findings, 1 Barritt DW Jordan SC Anticoagulant drugs in the treatment of pulmonary embolism: a controlled trial. Lancet. 1960; 1: 1309-1312 Abstract PubMed Scopus (1080) Google Scholar coupled with the other reports of the mortality of untreated PE, 3 Coon WW Willis PW Symous MJ Assessment of anticoagulant treatment of venous thromboembolism. Am J Surg. 1969; 170: 559-567 Google Scholar ,4 Zilliacus H On specific treatment of thrombosis and pulmonary embolism with anticoagulants. Acta Med Scand. 1946; 171: 1-221 Google Scholar ,5 Hermann RE Davis JH Holden WD Pulmonary embolism: a clinical and pathological study with emphasis on the effect of prophylactic therapy with anticoagulants. Am J Surg. 1961; 102: 19-28 Abstract Full Text PDF PubMed Scopus (64) Google Scholar ,6 Morrell MT Truelove SC Barr A Pulmonary embolism. BMJ. 1963; 2: 830-835 Crossref PubMed Scopus (52) Google Scholar would indicate that the mortality of untreated PE is approximately 30%. Given the fact that the mortality of PE in patients treated with heparin and warfarin is < 5%, 7 Carson JL Kelley MA Duff A et al. The clinical course of pulmonary embolism. N Engl J Med. 1992; 326: 1240-1245 Crossref PubMed Scopus (970) Google Scholar ,8 Douketis JD Kearon C Bates S et al. Risk of fatal pulmonary embolism in patients with treated venous thromboembolism. JAMA. 1998; 279: 458-462 Crossref PubMed Scopus (557) Google Scholar it is unlikely that there will be additional randomized clinical trials comparing heparin to placebo in patients with PE, or additional reports of the mortality of untreated PE.