Review of 6-month mortality following low-probability lung scans

Background: Ventilation perfusion lung scanning is widely used as a diagnos tic method for evaluating patients suspected of having pulmonary embolism ( PE). While lung scan interpretation is traditionally performed in terms of probability of PE (usually low, moderate or intermediate, and high), in rec ent years concern has been raised that the term low probability may be misl eading because adverse and even fatal sequelae of PE occasionally occur in such patients. To assess these concerns, a review of mortality in a large s eries of patients following low-probability lung scans was performed. Objective: To determine the B-month mortality in a consecutive series of pa tients following low-probability ventilation perfusion (V/Q) lung scans. Methods: Records of all patients who had low-probability V/Qscans during a 9-year period (1987-1995) were reviewed. Causes of mortality for those pati ents who died during the 6-month period after the index scan were establish ed from patients' charts, autopsy reports, and computer record data. Results: Of the total 536 evaluable patients, 83 (15%) died within 6 months of the date of the lung scan; 73 (88%) died while inpatients at the Seattl e Veterans Affairs Medical Center, Seattle, Wash, and the other 10 (12%) di ed at other facilities or at home. Pulmonary embolism was not reported as a suspected or probable contributing factor in any of the 83 deaths. Sixty-t hree patients (76%) who died had a diagnosis of either cancer (n = 32) or a dvanced cardiovascular disease (n = 31) at the time of their lung scans. Tw enty-six patients (31%) underwent autopsies, and PE was not identified on e xamination of the lungs in any of them. Of the 27 patients who died within 1 month of the scan date, 17 (63%) underwent autopsies. Conclusion: Review of data from all patients with low-probability V/Q scans and a follow-up of 6 months showed no documentation to attribute any death s to PE.