Trends in the utilization of computed tomography chest for acute pulmonary embolism in the emergency department and the yield in treatment
Authors: Wazzan Mohammad Abdulrahim , Abduljabbar Ahmed H. , Nasr Ranim Yahya , Shafi Ruba M. , Mimish Reem L. , Hashem Dalia A. 
Published: April 2024

Background:
Acute pulmonary embolism (PE) is a life-threatening condition with high mortality rates. Prompt and accurate diagnosis is crucial to prevent morbidity and mortality. Overutilizing computed tomography pulmonary angiography (CTPA) in low-risk patients can lead to unnecessary health-care costs and radiation exposure. Proper pretest probability assessment is recommended to guide the use of CTPA.

Aim:
This study aimed to evaluate the utilization of CTPA in the diagnosis of acute PE in the emergency department, with a focus on the application of pretest probability assessment (modified Wells score [MWS] and D-dimer). The primary objectives were to assess the extent of CTPA usage in low-risk patients, determine the effectiveness of D-dimer levels and the MWS in predicting PE, and identify areas for potential improvement in CTPA utilization to reduce unnecessary imaging and enhance patient care. In addition, the study aimed to evaluate the appropriateness of anticoagulant treatment in patients diagnosed with acute PE, particularly in cases of segmental/subsegmental PE.

Settings and Design:
A retrospective analysis was done on all suspected PE patients in the emergency room at our facility who underwent CTPA over 5 years. Patient demographic information, presenting complaints, physical examination findings, laboratory test results, and imaging findings were all included in the data collection.

Materials and Methods:
A retrospective review of 758 patient records at a tertiary hospital was conducted over 5 years. Data included demographics, presenting symptoms, test results, and imaging findings. D-dimer levels and the MWS were used for pretest probability evaluation. Anticoagulant treatment and appropriateness were also assessed.

Statistical Analysis:
Statistical analysis was carried out using RStudio (R version 4.3.0). Numerical variables were expressed as median (interquartile range), and frequencies and percentages were used to present categorical variables. A Fisher’s exact test was applied to assess the differences between patients who received anticoagulants and those who did not, as well as patients with PE statuses across D-dimer levels, Wells score categories, and receiving anticoagulants. A Kruskal–Wallis test explored the time to read reports between PE categories. P <0.05 indicated statistical significance.

Results:
Among 758 patients, 18.8% had acute PE, with 6.2% being segmental/subsegmental PE. The majority of cases (79.8%) were negative for PE. A high rate of CTPA utilization was observed, especially in low-risk patients. Sixty-eight percent of low-risk patients had negative PE results. Among patients with acute PE, lobar PE (36.4%) and segmental/subsegmental PE (32.9%) were the most common locations. D-dimer and MWS were underutilized.

Conclusions:
By identifying low-risk patients who might not need CTPA, compliance with pretest probability evaluation using the MWS and D-dimer levels can help minimize unnecessary imaging and its associated risks. The results showed that efforts should be made to adhere to guidelines and recommendations, especially if the patients were categorized as low risk based on MWS or normal D-dimer levels. This will eventually improve patient outcomes and lower health-care costs.