Is CT pulmonary angiography overutilized in the evaluation of patients with suspected pulmonary embolism? A retrospective study

Introduction: Despite the high mortality rate of acute untreated pulmonary embolism (PE) at 30%, diagnosing PE is challenging. While the prevalence of PE has decreased in recent years, the overuse of computed tomography pulmonary angiography (CTPA) remains a concern. The National Institute for Health and Care Excellence (NICE) provides guidelines using the Wells score for PE assessment. The Royal College of Radiologists (RCR) recommends a positive yield of 15.4% - 37% for CTPA tests. This study assesses the positive yield of CTPA for suspected PE patients and evaluates the potential reduction through Wells score/D-dimer assessment as recommended by NICE.

Methods: All patients who underwent CTPA between September 1, 2019, and January 31, 2020, at Salmaniya Medical Complex were included. Data on patient demographics and pre-CTPA workup were collected from electronic patient records (EPR) and stored in MS Excel 2019 for analysis.

Results: Of 188 suspected PE patients (mean age 50 ±12.3 years; 62.8% female), 12.2% were diagnosed with PE. None had documented Wells scores. A low-risk Wells score (≤4) was assigned to 68.6% of patients, with only 26.1% undergoing D-dimer testing. PE was confirmed in 4 patients with low-risk Wells scores and elevated D-dimers. All 10 patients with low-risk Wells scores and negative D-dimers were PE-negative.

Conclusion: In total, 5.3% - 47.9% of the CTPAs conducted could have been avoided by following NICE guidelines. We propose integrating an algorithm-based checklist with validated tools like the Wells and Geneva scores into the ePMA system to guide appropriate CTPA referrals, promote evidence-based decision-making, reduce unnecessary imaging, and optimize patient care and resource use.