Right ventricular base/apex ratio in the assessment of pediatric pulmonary arterial hypertension: Results from the European Pediatric Pulmonary Vascular Disease Network

Abstract

Background: Echocardiographic determination of RV end-systolic base/apex (RVES b/a) ratio was proposed to be of clinical value for assessment of pulmonary arterial hypertension (PAH) in adults.

Hypothesis: We hypothesized that the RVES b/a ratio will be affected in children with PAH and aimed to correlate RVES b/a ratio with conventionally used echocardiographic and hemodynamic variables, and with New York Heart Association (NYHA) functional class.

Methods: First we determined normal pediatric values for RVES b/a ratio in 157 healthy children (68 males; age range, 0.5-17.7 years). We then conducted an echocardiographic study in 51 children with PAH (29 males; age range, 0.3-17.8 years).

Results: RVES b/a ratio was lower compared with age- and sex-matched healthy controls (P < 0.001). In children with PAH, RVES b/a ratio decreased with worsening NYHA class. RVES b/a ratio inversely correlated with RV/LV end-systolic diameter ratio (ρ = -0.450, P = 0.001) but did not correlate with RV systolic function parameters (eg, tricuspid annular plane systolic excursion) and correlated with cardiac catheterization-determined pulmonary vascular resistance index (ρ = -0.571, P < 0.001). ROC analysis unraveled excellent performance of RVES b/a ratio to detect PAH in children (AUC: 0.95, 95% CI: 0.89-1.00, P < 0.001).

Conclusions: The RVES b/a ratio decreased in children with PAH compared with age- and sex-matched healthy subjects. The RVES b/a ratio inversely correlated with both echocardiographic and hemodynamic indicators of increased RV pressure afterload and with NYHA class, suggesting that RVES b/a ratio reflects disease severity in PAH children.

Keywords: Echocardiography; End-Systolic Base/Apex Ratio; Pediatric; Pulmonary Arterial Hypertension; Right Ventricle.

Figure 1

(A) An 11‐year‐old male child with normal RV and LV size and function. (B) An 11‐year‐old male child with IPAH. The red lines show the end‐systolic basal diameter and the end‐systolic apical diameter, respectively. The RVES b/a ratio represents a ratio of these 2 RV dimension parameters. Abbreviations: IPAH, idiopathic pulmonary arterial hypertension; LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle; RVES b/a, right ventricular end‐systolic base/apex

Figure 2

Age‐specific RVES b/a ratio z‐values for children with PAH (n = 51) and for age‐ and sex‐matched controls (n = 51). Abbreviations: PAH, pulmonary arterial hypertension; PH, pulmonary hypertension; RVES b/a, right ventricular end‐systolic base/apex

Figure 3

Differences in age specific RVES b/a ratio z‐values between different NYHA FC groups (n = 20 in class I, n = 22 in class II, n = 9 in class III). Abbreviations: FC, functional class; NYHA, New York Heart Association; RVES b/a, right ventricular end‐systolic base/apex