A 45-year-old physician is reviewing protocols for the diagnostic workup of pulmonary embolism (PE) in the emergency department. Match each of the following patient clinical presentations with the most appropriate next step in their diagnostic evaluation.
- A 65-year-old man with a high pretest probability of PE (Wells score 6.5) and an estimated glomerular filtration rate of 22 mL/min/1.73 m².Ventilation-perfusion (V/Q) scan
- A 45-year-old woman with a high pretest probability of PE who is persistently hypotensive (blood pressure 72/40 mm Hg) and too hemodynamically unstable for transport.Bedside transthoracic echocardiography
- A 30-year-old man with sudden-onset pleuritic chest pain, a low pretest probability of PE (Wells score 1.5), and no significant past medical history.Plasma D-dimer assay
- A 55-year-old woman with a high pretest probability of PE (Wells score 5), normal renal function, and stable hemodynamics.Computed tomography pulmonary angiography (CTPA)
Answer
The severe renal failure patient requires a V/Q scan. The hemodynamically unstable patient requires bedside echocardiography. The low clinical probability patient should receive a D-dimer assay. The stable, high clinical probability patient with normal renal function requires a CTPA.
Correct test sequencing requires triaging based on stability (unstable = bedside echo), then pretest probability (low = D-dimer rule out), and finally patient-specific contraindications (renal failure = V/Q scan instead of standard CTPA).
Step-by-Step Solution
Key Concept
The diagnostic algorithm for suspected pulmonary embolism depends heavily on hemodynamic stability, pretest probability, and absolute contraindications to intravenous contrast.