McMaster University

Pulmonary Embolism Diagnosis: Let’s practice what we preach. A quality improvement project to increase adherence to evidence-based PE diagnosis in the emergency department

Project Lead: Federico Germini, MD

Project AIM(s): The primary aim of the study is to reduce the number of non-appropriate
imaging for pulmonary embolism (PE) from 23% to 9%. We defined as non-appropriate imaging the computed tomographies or ventilation/perfusion scans ordered without D-dimer or despite a negative D-dimer.

Narrative Description

We developed a simple pulmonary embolism (PE) testing pathway and tested the clinical impact of a multi-faceted intervention to reduce the number of non-appropriate imaging for PE. Despite guidelines and recommendations aimed at reducing the use of advanced imaging techniques such as computed tomography pulmonary angiography (CTPA) or ventilation- perfusion scan (VQ) for diagnosis of PE, there is overuse of CTPA, which translates into excess radiation exposure, contrast- induced nephropathy, overtreatment, and wastage of time and healthcare resources. The intervention was based on an analysis of a series of think-aloud interviews with 63 ED physicians from four sites on barriers to using evidenced-based PE diagnosis algorithms in the ED as well as semi-structured interviews with 24 ED patients who were waiting to be tested for PE.  

We defined as non-appropriate imaging the CTPA or VQ scans ordered without D-dimer or despite a negative D-dimer. We also assessed the effect of the intervention on the following effect measures: proportion of patients tested for PE, proportion of patients tested for PE in adherence with the proposed protocol, diagnostic yield (percentage of positive exams) of imaging. Balancing measure will be the number of D-dimer ordered and the number of missed PE diagnosis.

We conducted a prospective multicenter intervention study in two emergency departments (EDs). The components of the intervention are as follows: (1) clinical leadership endorsement; (2) new diagnostic PE pathway that starts with D-dimer blood testing in all patients; (3) physician education; (4) personalized confidential physician feedback; and (5) patient information that informs patients on the testing process, as well as the risks and benefits of undergoing CT scanning.  

Between January 2018 and June 2021, 16,170 patients were tested for PE, 33.4% after intervention, 30.7% in the historical control, and 35.9% in the external control. Following intervention, 97.6% of patients were tested for PE in adherence with the PE pathway (aOR post- versus pre-intervention 8.30 (3.19, 21.57). The proportion who had imaging decreased from 38.7% to 35.9% (aOR 0.90: 0.82, 0.98). PE prevalence amongst all visits increased from 0.3 to 0.5% (aOR 1.60: 0.92, 2.77). The diagnostic yield of PE imaging, the proportion of proximal PEs, and the rate of missed PEs did not change. PE testing increased from 7.0 to 10.8% (aOR 2.01: 1.81, 2.24) and D-dimer testing from 6.5 to 10.6% (+4.1%: 3.8, 4.4). Conclusions, implementation of a simple PE testing pathway led to a proportional reduction in PE imaging and an increased rate of PE diagnosis.


Feasibility report: Germini F, Hu Y, Afzal S, Al-Haimus F, Puttagunta SA, Niaz S, Chan T, Clayton N, Mondoux S, Thabane L, de Wit K. Feasibility of a quality improvement project to increase adherence to evidence-based pulmonary embolism diagnosis in the emergency department. Pilot Feasibility Stud. 2021 Jan 4;7(1):4. doi: 10.1186/s40814- 020-00741-8. PMID: 33390190; PMCID: PMC7779326.


Presented as a poster at the 2021 conference of the International Society of Thrombosis and Haemostasias (ISTH):

Germini F, Al-haimus F, Hu Y, Niaz S, Clayton N, Mondoux S, Ibrahim Q, Thabane L, de Wit K. Pulmonary Embolism Diagnosis: Let’s Practice what we Preach. A Quality Improvement Study to Increase Adherence to Evidence-based PE Diagnosis in the Emergency Department [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). Accessed May 6, 2022.

Accepted as an oral presentation at the 2022 conference of the Canadian Association of Emergency Physician (CAEP), receiving the CAEP-CanVECTOR Research Abstract award.

Diagnostic quality problem type, failure, or category (symptoms, observed problems, gaps in performance) addressed by the intervention

  • Information gathering
  • Information integration
  • Information interpretation
  • Establishing an explanation (diagnosis)

Root causes/causative factors addressed by the intervention

  • Workflow (includes testing, follow-up, and referrals)

Setting of the diagnostic quality improvement intervention

  • Emergency department
  • Radiology/imaging