Yes, obtain the CT pulmonary angiogram urgently (stat)
In this 47-year-old woman with echocardiographic evidence of right ventricular enlargement, a CT pulmonary angiogram should be performed urgently to confirm or exclude pulmonary embolism, as the RV dysfunction indicates potential hemodynamic compromise that requires immediate diagnosis and treatment.
Clinical Reasoning
The presence of RV enlargement on echocardiography is a critical finding that elevates this patient's risk stratification, regardless of the mildly elevated D-dimer or negative lower extremity ultrasound. Here's why this needs urgent imaging:
Key Clinical Indicators Requiring Urgent Action
Right ventricular dysfunction signals potential hemodynamic significance. The 2019 ESC guidelines emphasize that echocardiographic findings of RV dysfunction are used for PE severity assessment and risk stratification 1. When RV enlargement is present, this suggests the PE (if present) may be causing significant cardiovascular strain, which directly impacts mortality risk.
The negative lower extremity duplex does not exclude PE. Compression ultrasonography has only 41% sensitivity for PE, though it maintains 96% specificity 1. The ESC guidelines state that if CUS is used to confirm PE and shows proximal DVT, assessment of PE severity should still be performed 1. In your case, the negative CUS simply means you cannot use it to confirm PE—it doesn't rule it out.
Why the Mildly Elevated D-dimer Matters
A positive D-dimer in the context of RV enlargement creates high clinical suspicion. The ACR Appropriateness Criteria (2022) clearly states that CTPA is the first-line diagnostic imaging tool after positive D-dimer examination and is routinely performed in this clinical scenario 2. The guidelines recommend CTPA is highly sensitive and specific for PE diagnosis 2.
The Diagnostic Algorithm Here
- Clinical probability assessment: This patient has intermediate-to-high probability given the RV enlargement finding
- D-dimer positive: Requires imaging regardless of the level being "mildly" elevated
- RV dysfunction present: Elevates urgency due to potential hemodynamic significance
- Negative CUS: Does not exclude PE given its low sensitivity
The ESC guidelines recommend initiating anticoagulation without delay in patients with high or intermediate clinical probability while diagnostic workup is in progress 1. Given the RV enlargement, you should consider starting anticoagulation immediately while arranging urgent CTPA.
Critical Pitfalls to Avoid
Do not be falsely reassured by "mildly" elevated D-dimer. Recent case reports demonstrate that PE can occur even with negative D-dimer results 3, 4, 5, so a mildly elevated value in the context of RV dysfunction is concerning. The D-dimer level itself doesn't determine urgency—the clinical picture does.
Do not delay imaging based on the negative lower extremity ultrasound. The meta-analysis cited in ESC guidelines shows CUS has poor sensitivity (41%) for PE 1. A negative CUS with RV dysfunction and positive D-dimer still requires CTPA.
The RV enlargement finding changes everything. One study showed that an echocardiogram without RV dysfunction combined with normal venous ultrasound had 96% negative predictive value for excluding PE 1. Your patient has the opposite scenario—RV enlargement is present, which significantly increases concern for PE.
Timing Considerations
"Stat" is appropriate here because:
- RV dysfunction indicates potential hemodynamic compromise
- The patient may progress to high-risk PE with hemodynamic instability
- Early diagnosis allows for risk-stratified treatment decisions
- If PE is confirmed with RV dysfunction, this may require escalated therapy beyond standard anticoagulation
The ESC guidelines specifically state that in suspected high-risk PE with hemodynamic instability, emergency CTPA is recommended 1. While your patient isn't currently unstable, the RV enlargement suggests she's at risk for decompensation, warranting urgent rather than routine imaging.