CT pulmonary angiography after total joint arthroplasty: overdiagnosis and iatrogenic harm?

Background: CT pulmonary angiography (CTPA) has become widely adopted to detect pulmonary embolism (PE) after total joint arthroplasty (TJA). CTPA is a sensitive tool, which has the ability to detect emboli that may be clinically insignificant. This may lead to iatrogenic harm from overtreatment.

Questions/purposes: The purpose of this study was to assess changing prevalence, mortality, treatment complications, and resource consumption associated with PE after TJA before and after the introduction of CTPA.

Methods: The Nationwide Inpatient Sample was used to identify 2,335,248 patients undergoing TJA from 1993 to 1998 before the introduction of CTPA and 6,321,671 patients from 1999 to 2008 after the introduction of CTPA. Bivariate and multivariate regression analysis was performed to compare changing prevalence of PE, mortality, potential treatment complications of anticoagulation, length of stay, and total charges before and after the introduction of CTPA in patients with PE.

Results: In-hospital diagnosis of PE after TJA increased (p < 0.001) from an average of 0.27% to 0.37% after the introduction of CTPA. All-cause mortality in patients with a diagnosis of PE decreased (p < 0.001) from 11.5% to 4.6% (odds ratio, 2.3; 95% confidence interval, 2.1-2.6) after the introduction of CTPA. Overall, PE was associated with increased (p < 0.001) risks for hematoma/seroma, postoperative infection, gastrointestinal bleed, and drug-related thrombocytopenia, although the prevalence of these complications has decreased after 1998 (p < 0.001). Length of stay doubled for patients with PE (both before and after CTPA) and total charges increased over 69% in both study periods for these patients.

Conclusions: Adoption of CTPA appears to be associated with an increase in the diagnosis of PE after TJA and an associated decrease in case-fatality. Although CTPA may improve our ability to diagnose PE and possibly reduce mortality, the observed decrease in case-fatality could also be explained by the overdiagnosis of clinically unimportant emboli. The diagnosis of PE was strongly associated with potential iatrogenic harm from anticoagulation and increased length of stay and hospital charges in this study, emphasizing the importance of further investigation to define the role of CTPA in the diagnosis and treatment of PE after TJA.