What is the best echocardiogram (echo) parameter to assess right ventricular (RV) failure?

Best Echocardiographic Parameters for Assessing Right Ventricular Failure

Right ventricular ejection fraction (RVEF) is the gold standard parameter for assessment of RV systolic function and failure, with established prognostic value at baseline and during follow-up. 1

Primary Parameters for RV Failure Assessment

Most Valuable Parameters (in order of clinical utility)

1. RVEF (Right Ventricular Ejection Fraction)

   • Gold standard for RV systolic function assessment
   • Highly reproducible
   • Strong prognostic value at baseline and during follow-up
   • Abnormal when <40%
   • Limitations: Assessment is time-consuming; tricuspid regurgitation can overestimate RVEF 1

2. TAPSE (Tricuspid Annular Plane Systolic Excursion)

   • Easy and quick assessment
   • High reproducibility
   • Strong prognostic value at baseline
   • Normal: >17 mm; Abnormal: <17 mm
   • Limitations: Less suitable for serial assessment; may be misleading in severe tricuspid regurgitation 1, 2

3. RV FAC (Fractional Area Change)

   • Good correlation with RVEF
   • Reflects both longitudinal and radial components of RV contraction
   • Normal: 49 ± 7%; Abnormal: <35%
   • Prognostic value at baseline in pulmonary arterial hypertension
   • Limitations: Less reproducible than TAPSE; neglects RV outflow tract contribution 1, 2

4. TAPSE/PASP Ratio

   • Provides an index of in vivo RV length-force relationship
   • Improved prognostic resolution compared to individual parameters
   • Abnormal when <0.36 mm/mmHg
   • Reflects RV contractile function regardless of LV dysfunction type 3

Secondary Parameters

1. Tissue Doppler-derived tricuspid annular systolic velocity (S')

   • Normal: >9.5 cm/sec; Abnormal: <9.5 cm/sec
   • Reflects longitudinal RV function
   • Has prognostic value 2

2. RV Free Wall Strain

   • Shows closest association with 3D-derived RVEF
   • Normal: >-20%; Abnormal: >-20% (less negative)
   • Early detection of RV dysfunction
   • Can detect differences when other measurements fail 1, 2

3. Hepatic Vein Flow

   • Systolic flow reversal indicates severe tricuspid regurgitation and RV dysfunction
   • Normal: Systolic dominance; Abnormal: Systolic blunting or reversal 1

4. RV Volumes

   • Prognostic value at baseline and during follow-up
   • RV enlargement is a sign of chronic RV failure
   • Normal values: RV basal diameter 25-41 mm, RV mid diameter 19-35 mm 1, 2

Integrated Assessment Approach

For comprehensive RV failure evaluation, use this algorithm:

1. Start with RVEF assessment (when available via 3D echo or CMR)

   • If RVEF <40%, RV failure is present 1

2. If RVEF unavailable, use this combination:

   • TAPSE <17 mm
   • RV FAC <35%
   • S' <9.5 cm/sec
   • When all three parameters are abnormal with severe RV enlargement, severe RV dysfunction is present 2

3. Calculate TAPSE/PASP ratio

   • Ratio <0.36 mm/mmHg indicates poor prognosis 3

4. Assess for additional signs of RV failure:

   • Moderate/severe tricuspid regurgitation
   • Systolic flow reversal in hepatic veins
   • Increased right atrial pressure
   • Paradoxical ventricular septal motion 1

Common Pitfalls and Caveats

• TAPSE and S' may be misleading in patients with severe tricuspid regurgitation 2
• Doppler gradients may be unreliable (overestimation) in patients with tubular stenosis and in patients with stenoses in series 1
• RV FAC calculation requires accurate endocardial border tracing, which can be challenging in patients with poor acoustic windows 2
• RVEF assessment by 3D echocardiography tends to underestimate volumes compared to CMR 1
• When assessing RV function in patients with left ventricular assist devices, parameters like TAPSE combined with other scores provide better prediction of RV failure than individual measurements 4

By using these parameters in a systematic approach, clinicians can accurately assess RV failure, which has significant implications for patient morbidity, mortality, and quality of life.