Declining Mortality From Pulmonary Embolism In Surgical Patients

The frequency and clinical characteristics of autopsied surgical patients dying with pulmonary embolism (PE) were studied at a University hospital from 1966-1976. During this period a standard autopsy protocol was in use. All patients in whom PE occluded the equivalent of at least one lobar artery were studied. Information collected in all adult deaths confirmed the year to year similarity of patient characteristics and likelihood of autopsy. In order to assess the role of PE in a patient’s death, cases were grouped separately by 2 criteria: 1) according to size of PE (3 groups: greater than 2/3 of pulmonary vasculature occluded, 1/2 - 2/3 occluded, less than 1/2 occluded); 2) weighing competing causes of death by having 3 physicians (randomly selected from a pool of 25) judge the likelihood of death after 1 month had PE been prevented (classifying them as primary PE death, contributory PE death, and death from competing causes). Sixty percent (900/1489) of surgical deaths were autopsied and 7.7% (69) had large emboli. The percentage of deaths from PE, using either criteria, has declined significantly (p<0.01) over time (1966-71 vs 1972-76): 10.5% to 4.5% for all cases studied and 5.5% to 2.1% in those where PE was the primary or a contributory cause of death. PE was the primary or a contributory cause of death in 3.9% (34 cases) of these autopsies. The clinical diagnosis of PE was considered in only 17% (6) of these cases but 63% (22) had no symptoms suggestive of PE prior to death. An infiltrate or effusion, however, was present in 60% (21) of cases and 80% (28) had 2 or more major risk factors for PE. In contrast to previous studies, this study demonstrates an impressive decline in surgical deaths from PE from 1966-1976 despite no routine use of prophylactic anticoagulation.