Clinical validity of a normal pulmonary angiogram in patients with suspected pulmonary embolism - A critical review

AIM: To determine the validity of a normal pulmonary angiogram in the exclu sion of pulmonary embolism (PE), based on the safety of withholding anticoa gulant therapy in patients with a normal pulmonary angiogram. MATERIALS AND METHODS: A review of English reports published between 1965 a nd April 1999 was carried out. Eligible articles described prospective stud ies in patients with suspected PE and a normal pulmonary angiogram, who rem ained untreated and were followed-up for a minimum of 3 months. Articles we re evaluated by two authors, using pre-defined criteria for strength of des ign. End points consisted of fatal and non-fatal recurrent thromboembolic e vents. A sensitivity analysis was performed, by removing one study at a tim e from the overall results and by comparing pre- and post-1990 publications . RESULTS: Among 1050 patients in eight articles included in the analysis, re current thromboembolic events were described in 18 patients (1.7% 95% CI: 1 .0-2.7%). These were fatal in three patients (0.3% 95% CI: 0.02-0.7%). The recurrence rate of PE decreased from 2.9% (95% CI: 1.4-6.8%) before 1990 to 1.1% (95% CI: 0.5-2.2%) after 1990. CONCLUSION: It would appear that the ability to exclude PE by angiography h as improved over the years, as indicated by recurrence rate of PE. The low recurrence rate of PE supports the validity of a normal pulmonary angiogram for the exclusion of PE. (C) 2001 The Royal College of Radiologists.