Echocardiographic Predictors of Survival in Paediatric Pulmonary Hypertension

Background: Transthoracic echocardiography (TTE) remains the most important non-invasive tool for clinical-follow up of patients with pulmonary hypertension (PH). Data on which echocardiographic parameters are predictive of survival in children are sparse.

Methods: Forty-one children (age 8.0 ± 5.6 years, 44% male, 58% WHO class III) with confirmed PH and structurally normal hearts were included (66% with idiopathic PH). All underwent a standardized, protocolized TTE at a tertiary center for pediatric PH. A combined end-point of death and transplantation was used.

Results: During a median follow-up of 4.4 years [IQR 2.0–9.2 years], 16 patients met the combined endpoint (including 13 deaths). On univariate Cox proportional survival analysis, the following echocardiographic parameters were significantly related to outcome: left ventricular systolic and diastolic eccentricity indices (HRs: 1.06; p = 0.02 and 1.16; p = 0.004, respectively), right ventricular systolic and diastolic diameters (HRs: 1.06; p = 0.02 and 1.75; p = 0.01), pulmonary valve dimension z-score (HRs: 1.26; p = 0.02), right atrial area z-score (HR: 1.21, p = 0.002) as well as E- and A-wave tissue Doppler velocities on the left ventricular side (HRs: 1.25; p = 0.04 and 0.80;p = 0.04). On multivariable analysis left ventricular diastolic eccentricity index (HR: 1.26, p = 0.03) and right atrial area z-score (HR: 1.16, p = 0.02) remained predictive of outcome (joint c-statistic 0.73, p = 0.003). In addition, mixed venous oxygen saturation on cardiac catheterization (HR: 0.95, p = 0.04), oxygen saturation in room air (HR 0.85, p = 0.01) and heart rate at rest (HR: 0.97, p = 0.045) were predictive of outcome.

Conclusion: Larger right atrial size, as well as the degree of interseptal shift toward the left ventricle (eccentricity index), appears to be particularly associated with adverse outcome in pediatric PH patients. These parameters were superior to RV function in the current study. These findings underline the importance of interventricular interaction and left-ventricular compromise in patients with PH. Standardized TTE protocols focusing on outcome prediction require further attention and should be integrated into clinical practice. Ideally, these results should be confirmed in larger multi-center trials.