Bypassing D-dimer Testing in Suspected High-Risk Pulmonary Embolism in the Emergency Department: A Case Report.

Pulmonary embolism (PE) remains a leading cause of sudden hemodynamic deterioration and death in emergency department patients. Although diagnostic algorithms frequently incorporate D-dimer testing, in patients with high clinical probability or hemodynamic instability, definitive imaging should not be delayed. We report a case of a 74-year-old man presenting with syncope, hypoxemia, and hypotension, in whom immediate computed tomography pulmonary angiography (CTPA) was performed without prior D-dimer testing due to strong clinical suspicion of high-risk PE. Imaging revealed extensive bilateral pulmonary emboli with radiological signs of right ventricular strain, which were subsequently supported by point-of-care echocardiography. Due to recent head trauma, systemic thrombolysis was contraindicated, and the patient was referred for urgent mechanical thrombectomy. This case highlights the importance of clinical judgment and early imaging in high-risk PE and emphasizes that laboratory testing should not delay life-saving diagnostic and therapeutic decisions in unstable patients.