# Computed Tomography Pulmonary Angiography (CTPA) Utilization in Suspected Pulmonary Embolism Patients Based on Age-Adjusted D-dimer Thresholds and Pulmonary Embolism Rule-Out Criteria (PERC) Score: A Retrospective Analysis

## TL;DR

This study found that many low-risk patients received unnecessary CT scans for suspected blood clots in the lungs, suggesting better use of risk tools could reduce overuse.

## Contribution

The study highlights overuse of CTPA in low-risk PE patients and advocates for better adherence to risk stratification tools.

## Key findings

- Only 14.6% of CTPA scans confirmed pulmonary embolism.
- 46.93% of patients under 50 with a PERC score of 0 had unnecessary imaging.
- 13 patients aged 50+ with normal D-dimer levels had negative CTPA results.

## Abstract

Computed tomography pulmonary angiography (CTPA) is the gold standard for diagnosing pulmonary embolism (PE), but its overuse can lead to unnecessary radiation exposure and increased healthcare costs. This clinical audit evaluated adherence to National Institute for Health and Care Excellence (NICE) guidelines (NG 158) for CTPA utilization in suspected PE cases. A retrospective analysis of 164 patients at the Royal Stoke University Hospital assessed the application of the pulmonary embolism rule-out criteria (PERC) score in patients aged 18-49 and age-adjusted D-dimer thresholds in those aged 50 and above. Findings revealed that only 14.6% of CTPA scans confirmed PE. Notably, 46.93% of patients under 50 with a PERC score of 0 underwent unnecessary imaging, and 13 patients aged 50 and above with normal age-adjusted D-dimer levels had CTPA, all yielding negative results. These findings indicate a significant overuse of CTPA in low-risk patients. Improving adherence to risk stratification tools through clinician education, decision-support tools, and increased awareness could reduce unnecessary imaging, minimize radiation exposure, and optimize healthcare resource utilization.