Pulmonary embolism (PE) is the third most common presenting acute cardiovascular syndrome behind myocardial infarction and cerebral vascular event, resulting in significant harm and death. Different clinical decision-making rules exist to guide clinicians investigating PE, to risk stratify patients based on presenting signs and symptoms; into low, moderate or high-risk. This helps direct further investigations and imaging, such as blood tests (D.dimer), computed tomography pulmonary angiogram (CTPA), and ventilation/perfusion scan (V/Q).
Currently, a blood test is a first line test used to help identify which lower risk patients might require further investigation with medical imaging. Medical imaging adds cost, prolongs hospital stay and exposes the patient to radiation and IV contrast. This retrospective study will determine in the Australian context, whether applying a higher cut off D.dimer to low risk patients who present to an urban emergency department is a safe strategy in ruling out PEs. An Australian study is important due to significant contextual issues in the D.dimer testing across different countries despite decision rules currently available.
The research team at the Caboolture Hospital evaluated 1672 patients retrospectively. Out of this cohort, 413 patients were identified with the higher D.dimer cut-off. 323 of these patients underwent further imaging, which could have been avoided if using the higher D.dimer cut-off.
The research team also compared between the patients who received imaging vs those who did not, and they observed that the patients in the non-imaging group had significantly shorter average length of stay in the ED.
When looking at the number of potential PEs missed by applying the higher D.dimer cut-off, there was one patient that would have been missed.
- Furlong, K., D.dimer adjusted to low clinical probability in the diagnosis of suspected pulmonary embolism – is it safe in the urban emergency department?. Caboolture and Kilcoy Hospitals and Woodford Corrections Health 2022 Research Symposium, Oct 2022.