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.