Underuse of Clinical Decision Rules and d-Dimer in Suspected Pulmonary Embolism: A Nationwide Survey of the Veterans Administration Healthcare System

Abstract

Purpose: The diagnosis of pulmonary embolism (PE) remains a challenge. CT pulmonary angiography (CTPA) for suspected PE has become the primary imaging modality, but concerns regarding overutilization, overdiagnosis, radiation, and costs have led to algorithms that combine a clinical decision rule (CDR) and highly sensitive d-dimer to identify patients in whom PE can be safely excluded without further studies. This has been identified as a top five Choosing Wisely recommendation in pulmonary medicine, but adherence is modest at best and actual utilization is unknown. Therefore, a survey was conducted to determine the prevalence of this approach in the Veterans Administration (VA) healthcare system.

Methods: A web-based questionnaire survey (SurveyGizmo.com) was developed and validated to query the utilization of CDR ± d-dimer in suspected PE. Key stakeholders identified from national VA mailing lists of radiology, pulmonary, and emergency medicine chiefs were sent an email describing the survey and provided a link for response. This study was reviewed and approved by our local institutional review board and accessing the link represented consent for participation. No personally identifiable data were collected and a drawing for a gift card was provided as an incentive.

Results: There were a total of 159 responses, with 120 fully completed surveys for analysis. The majority of respondents were chiefs (63%) with 11+ years of experience (80%), from hospitals with house staff (86%) and an emergency department (97%). Respondents were from emergency medicine (31%), pulmonary (27%), radiology (26%), and other departments (9%). The overwhelming majority of respondents (85%) did not require results of a CDR ± d-dimer before ordering a CTPA. Only 6.7% required a CDR + d-dimer, with others requiring either only a CDR (5.8%) or d-dimer (2.5%). The most common CDR was the Wells score, with only one using the Pulmonary Embolism Rule-Out Criteria. Nine of 18 (50%) regional Veterans Integrated Service Networks reported at least one site requiring a CDR before CTPA. An average of 9.6 CTPAs were estimated to be performed per week. Sorted by CDR and d-dimer use, 8 (CDR + d-dimer), 6.9 (CDR only), 8 (d-dimer only), 10.1 (no requirements) CTPA studies were performed weekly. The average CTPA yield for PE was estimated at 11.9% (CDR + d-dimer), 8% (CDR only), 2.5% (d-dimer only), and 7.6% (no requirements).

Conclusions: The vast majority of hospitals within the VA system do not use a CDR ± d-dimer in the evaluation of patients with suspected PE. Utilization of a CDR and d-dimer may decrease CTPA utilization and increase yield, but this assessment is limited by the scope of the survey.

Clinical implications: CDR-guided strategies are recommended in the evaluation of suspected PE. Adherence within the VA healthcare system is very low. Further investigation is warranted to better characterize and improve the adherence to CDR-guided strategies and CTPA utilization.

Keywords: CT pulmonary angiography; Clinical decision rule; d-dimer; pulmonary embolism; ventilation-perfusion scans.