Computed Tomography Angiography for Detection of Pulmonary Embolism in Western Australia Shows Increasing Use with Decreasing Diagnostic Yield

Computed tomography pulmonary angiogram ordering, adherence to decision rules and yield in the emergency department: An observational study

OBJECTIVE

Pulmonary embolism (PE) frequently requires diagnosis through CT pulmonary angiogram (CTPA). Appropriate application of evidence-based clinical decision tools can reduce unnecessary CTPAs. This study assessed adherence to and the efficacy of various aspects of the Queensland Health suspected PE diagnostic pathway, including Wells score, PE rule out criteria (PERC) and age-adjusted D-dimer interpretation.

METHODS

Retrospective study of CTPAs ordered from 1 January to 30 April 2023 in a tertiary and urban ED in Southeast Queensland. Data on clinical variables, D-dimer and CTPA results were collected through medical record and radiology database review. Descriptive analyses were used to determine adherence to Queensland guidelines and performance of D-dimer interpretation tools (including comparison of age-adjusted PE with a new pre-test probability [PTP]-based model using D-dimer cut-off <1000 ng/mL for Wells score ≤4 and 500 ng/mL for Wells score 4.5-6).

RESULTS

A total of 573 CTPAs were available for analysis with a 12.4% (95% confidence interval 10.0-15.4) diagnostic yield. Stratification by Wells score showed yields of 4.0%, 18.5% and 41% for low-, moderate- and high-risk patients, respectively. Twenty-five patients with low-PTP who received CTPA could have been excluded with the PERC rule. Age-adjusted D-dimer interpretation may have prevented 26 CTPAs with no false negatives, whereas PTP approach may have prevented 128 CTPAs with four false negatives.

CONCLUSION

Guideline adherence can be improved, and adherence to existing clinical decision tools may reduce unnecessary CTPA ordering and increase diagnostic yield. The use of the age-adjusted D-dimer had good sensitivity, whereas the new PTP approach will require further prospective research.

Influencing factors on the time to CT in suspected pulmonary embolism: an explorative investigation

Pulmonary embolism is a potentially fatal condition with increased mortality if anticoagulation is delayed. This study aimed to find influencing factors on the duration from requesting a computed tomography (CT) pulmonary angiography (CTPA) to performing a CTPA in suspected acute pulmonary embolism. In 1849 cases, automatically generated time data were extracted from the radiological information system. The impact of the distance to the scanner, case-related features (sector of patient care, triage), and workload (demand for CTs, performed CTs, available staff, hospital occupancy) were investigated retrospectively using multiple regression. The time to CTPA was shorter in cases from the emergency room (ER) than in inpatients and outpatients at distances below 160 m and 240 m, respectively. While requests from the ER were also performed faster than cases from regular wards (< 180 m), no difference was found between the ER and intensive care units. Compared to "not urgent" cases, the workflow was shorter in "urgent" (- 17%) and "life-threatening" (- 67%) situations. The process was prolonged with increasing demand (+ 5%/10 CTs). The presented analysis identified relevant in-hospital influences on the CTPA workflow, including the distance to the CT together with the sector of patient care, the case triage, and the demand for imaging.

Overuse of Computed Tomography Pulmonary Angiography and Low Utilization of Clinical Prediction Rules in Suspected Pulmonary Embolism Patients at a Regional Australian Hospital

A pulmonary embolism (PE) is an obstruction in the pulmonary arterial system and may include non-specific signs and symptoms. Clinical prediction rules (CPRs) assess the pretest probability (PTP) of a PE to prevent the overuse of computed tomography pulmonary angiography (CTPA). CTPA overuse results in patient harm and health system waste. This study aimed to evaluate CTPA usage in an Australian regional hospital through analyzing CTPA encounters. A retrospective chart analysis was undertaken of 100 CTPAs conducted at an Australian regional hospital from April to May 2023. Analysis was undertaken for parameters including risk factors, signs and symptoms, investigations, and the use of CPRs. Overall, 86% of patients had signs and/or symptoms of a PE within a week of examination, and 6% of the population had signs of deep vein thrombosis. More than half of the population had no risk factors, while the most prevalent risk factors were a recent history of immobilization/trauma and/or having surgery that required general anesthesia in the last 4 weeks. The most common co-morbidity was chronic lung disease (11%). For the pre-test diagnostic workup, the ECG was the most ordered investigation. The Wells' score was used at 10%, while most patients did not have any CPRs applied. The prevalence of PEs discovered on CTPAs was 9%. CPRs were under-utilized in this Australian regional hospital. The D-dimers for ruling out subjects with low PTP derived from CPRs were also underused. This led to the inappropriate overordering of CTPAs, resulting in negative implications for patients and unnecessary costs to the health system.

The Utilisation of Computed Tomography Pulmonary Angiography in a Regional Victorian Emergency Department

BACKGROUND

Pulmonary embolism (PE) is a critical condition with various recognized risk factors. This study investigates these factors in a regional Australian population.

AIMS

The primary aim is to examine the significance of traditional risk factors in the clinical decision to request a computed tomography pulmonary angiography (CTPA) scan for suspected PE within this population and assess the association between the timing of CTPA requests (office vs. after-hours) and PE occurrence.

METHODS

In this single-center retrospective study, we analyzed data from 434 patients undergoing CTPA at Goulburn Valley Health's (GVH) emergency department (ED) between January and August 2022. Covariates included age, clinical indications, and medical background. Statistical tests were applied with a p-value <0.05 indicating significance.

RESULTS

Pulmonary embolism was diagnosed in 39 (20.9%) males and 17 (6.9%) females, with a mean age of 65.04 years (SD: 16.11). Univariate regression indicated a positive association between age and PE. Multivariate analysis showed a significant positive association for unilateral lower limb (LL) swelling/deep vein thrombosis (DVT) (OR: 5.474, p=0.003) and a significant negative association for being female (OR: 0.308, p<0.001). Variables such as shortness of breath, tachycardia, syncope, and chest pain were not significantly associated with PE. No association was found between CTPA request time and PE (χ²=0.9535, df=1, p=0.3288).

CONCLUSION

Increasing age and unilateral LL swelling/DVT are significantly associated with PE. Some signs and symptoms showed negative or positive odds but were not statistically significant. The timing of CTPA requests did not correlate with PE incidence.

How Tasmanian Emergency Departments 'Choose Wisely' When Investigating Suspected Pulmonary Embolism

Overuse of computed tomography pulmonary angiograms (CTPAs) for diagnosis of pulmonary embolism (PE) has been recognised as an issue for over ten years, with Choosing Wisely Australia recommending that CTPAs only be ordered if indicated by a clinical practice guideline (CPG). This study aimed to explore the use of evidence-based practice within regional Tasmanian emergency departments in relation to CTPA orders by determining whether CTPAs were ordered in accordance with validated CPGs. We conducted a retrospective medical record review of all patients who underwent CTPA across all public emergency departments in Tasmania between 1 August 2018 and 31 December 2019 inclusive. Data from 2758 CTPAs across four emergency departments were included. PE was reported in 343 (12.4%) of CTPAs conducted, with yield ranging from 8.2% to 16.1% between the four sites. Overall, 52.1% of participants had neither a CPG documented, nor a D-dimer conducted before their scan. A CPG was documented before 11.8% of scans, while D-dimer was conducted before 43% of CTPAs. The findings presented in this study indicate that Tasmanian emergency departments are not consistently 'Choosing Wisely' when investigating PE. Further research is required to identify explanations for these findings.