Is echocardiography (echo) indicated for all patients with pulmonary embolism (PE)?

Is Echocardiography Indicated for All Pulmonary Embolism Cases?

No, echocardiography is not indicated for all pulmonary embolism cases—it should be reserved for hemodynamically unstable patients (high-risk PE) and for risk stratification in confirmed intermediate-risk PE, but is explicitly not recommended as part of routine diagnostic workup in hemodynamically stable patients with suspected PE. 1, 2

Specific Indications for Echocardiography in PE

High-Risk PE (Hemodynamically Unstable Patients)

Echocardiography is strongly recommended in the following scenarios:

• Immediate bedside TTE when shock or hypotension is present and CT pulmonary angiography is not immediately available or the patient is too unstable for transport 1, 2
• The absence of echocardiographic signs of right ventricular overload or dysfunction virtually excludes massive PE as the cause of hemodynamic instability 1, 2
• In highly unstable patients, unequivocal echocardiographic evidence of RV dysfunction is sufficient to prompt immediate reperfusion treatment without further testing 2
• TTE helps differentiate other causes of shock including pericardial tamponade, acute valvular dysfunction, severe LV dysfunction, or aortic dissection 2

Intermediate-Risk PE (Hemodynamically Stable with RV Dysfunction)

Echocardiography is recommended for:

• Risk stratification in confirmed PE to identify patients at intermediate risk who may benefit from more intensive monitoring or escalated treatment 1, 2
• Guiding therapeutic decisions in patients with PE at intermediate risk 1, 2
• Evidence of RV dysfunction on TTE identifies normotensive patients at higher risk, with a 2.29-fold increase in mortality compared to those without RV dysfunction 2

When Echocardiography May Be Reasonable

• Distinguishing cardiac versus non-cardiac etiology of dyspnea when all clinical and laboratory clues are ambiguous 1, 2
• Searching for pulmonary emboli and suspected clots in the right atrium, ventricle, or main pulmonary artery branches 1

When Echocardiography Is NOT Recommended

The European Society of Cardiology explicitly states that TTE is not recommended for:

• Elective diagnostic strategy in hemodynamically stable, normotensive patients with suspected PE 1, 2
• Routine diagnostic workup in hemodynamically stable patients with suspected PE 2

This recommendation is based on the limited sensitivity of echocardiography for detecting PE in stable patients (sensitivity ranges from 29-56% in research studies) 3, 4, making it inadequate as a screening or diagnostic test in this population.

Key Echocardiographic Findings in PE

When echocardiography is performed, the following findings suggest RV pressure overload and dysfunction:

• RV dilatation: RV/LV end-diastolic diameter ratio >0.6 or RV/LV area ratio >1.0 1, 2
• RV hypokinesia: May be global or limited to mid-RV free wall with sparing of apex (McConnell sign, though not specific for PE) 1
• Abnormal interventricular septal motion 1, 2
• Tricuspid regurgitation with elevated gradient 2
• Decreased tricuspid annular plane systolic excursion (TAPSE <16 mm) 2

Important Clinical Caveats

Pulmonary artery systolic pressure interpretation:

• In acute PE, the RV can only generate PAsP up to 60 mmHg acutely, corresponding to tricuspid regurgitant jet velocities of 2.5-3.5 m/s 1
• PAsP >60 mmHg suggests a chronic process (repeated PE episodes or chronic pulmonary disease) rather than acute PE 1

Diagnostic limitations:

• Echocardiography has high specificity (87-96%) but poor sensitivity (29-56%) for diagnosing PE in unselected patients 3, 4
• The ACR Appropriateness Criteria note that all patients with echocardiographic findings suggestive of PE will still require CT pulmonary angiography to confirm the diagnosis 1
• Adding echocardiography to routine diagnostic workup would avoid only 12-28% of standard diagnostic procedures but would cause inappropriate treatment in 4-14% of patients 4

Prognostic Value Beyond Diagnosis

When PE is confirmed, echocardiographic detection of the following carries prognostic significance:

• Right heart thrombi (present in 4-18% of PE patients) are associated with high early mortality 2
• Patent foramen ovale with right-to-left shunt increases risk of death, stroke, and peripheral arterial embolism through paradoxical embolism 2
• Serial echocardiography can monitor treatment response and RV recovery 5

Practical Algorithm

For suspected PE:

1. Hemodynamically unstable (shock/hypotension)? → Immediate bedside TTE 1, 2
2. Hemodynamically stable? → CT pulmonary angiography is first-line; do not perform TTE for diagnosis 1, 2
3. PE confirmed and hemodynamically stable? → Consider TTE for risk stratification to assess RV function 1, 2