Ordering CT pulmonary angiography to exclude pulmonary embolism: defense versus evidence in the emergency room

Abstract

Purpose: To identify reasons for ordering computed tomography pulmonary angiography (CTPA), to identify the frequency of reasons for CTPA reflecting defensive behavior and evidence-based behavior, and to identify the impact of defensive medicine and of training about diagnosing pulmonary embolism (PE) on positive results of CTPA. Methods: Physicians in the emergency department of a tertiary care hospital completed a questionnaire before CTPA after being trained about diagnosing PE and completing questionnaires. Results: Nine hundred patients received a CTPA during 3 years. For 328 CTPAs performed during the 1-year study period, 140 (43 %) questionnaires were completed. The most frequent reasons for ordering a CTPA were to confirm/rule out PE (93 %), elevated D-dimers (66 %), fear of missing PE (55 %), and Wells/simplified revised Geneva score (53 %). A positive answer for ''fear of missing PE'' was inversely associated with positive CTPA (OR 0.36, 95 % CI 0.14-0.92, p = 0.033), and ''Wells/simplified revised Geneva score'' was associated with positive CTPA (OR 3.28, 95 % CI 1.24-8.68, p = 0.017). The proportion of positive CTPA was higher if a questionnaire was completed, compared to the 2-year comparison period (26.4 vs. 14.5 %, OR 2.12, 95 % CI 1.36-3.29, p \ 0.001). The proportion of positive CTPA was nonsignificantly higher during the study period than during the comparison period (19.2 vs. 14.5 %, OR 1.40, 95 % CI 0.98-2.0, p = 0.067). Conclusion: Reasons for CTPA reflecting defensive behavior-such as ''fear of missing PE''-were frequent, and were associated with a decreased odds of positive CTPA. Defensive behavior might be modifiable by training in using guidelines.

Perfusion SPECT in patients with suspected pulmonary embolism: how much sensitivity is needed to keep patients alive?

“…This trend has also been observed in Europe. In Switzerland, such defensive behaviour is frequent and is consistent with a low prevalence of positive CTPA findings [28]. The increased incidence of PE has been found to be strongly correlated with the increased use of CTPA [16].…”

The Economic Value of Hybrid Single‐photon Emission Computed Tomography With Computed Tomography Imaging in Pulmonary Embolism Diagnosis

“…A recent survey of physicians ordering CTPA scans for diagnosing PE found that defensive behavior (e.g., fear of missing PE, threat of malpractice litigation) was a factor in nearly three of five scans. These factors kept pace with other evidence‐based medicine factors for driving the post‐imaging clinician decision making 30. A 2005 survey of Pennsylvania ED physicians found that 63% ordered radiologic tests that were not indicated, while 93% of physicians, in general, practice defensive medicine 31.…”

“…A Massachusetts‐based survey revealed that 23% of all types of CTs were ordered for defensive reasons 32. While the role of defensive medicine in driving up healthcare costs is controversial, these behaviors are estimated to cost the US healthcare system up to $45 billion to $100 billion annually and are thought to account for 5% to 25% of all US medical care costs 30. While behavior modification in dealing with physician risk aversion has a definite role to play in using imaging resources judiciously and efficiently, this also highlights an unmet need that SPECT/CT can potentially fill as a result of its superior diagnostic accuracy and efficiency, which reduces the overall cost burden.…”

Medical emergencies: pulmonary embolism and acute severe asthma

“…It appears that, even with risk prediction tools, only a small minority (10-20%) of patients who have a CT pulmonary angiogram (CTPA) have a PE [13]. As a profession, we are ordering CTPAs out of paranoia [14] and ignoring the radiation dose required, which is equivalent Figure 1Pathophysiology of pulmonary embolus. Copied with permission from [50].…”