Prognostic value of deep echocardiographic phenotyping in pulmonary arterial hypertension

Abstract

Background: A novel approach to derive prognostic information from echocardiography in pulmonary arterial hypertension (PAH) is to define a phenotype of right heart function combining standard echocardiographic parameters which describe right ventricular pump function and systemic venous congestion. We tested the hypothesis that the combination of advanced strain imaging parameters could yield high prognostic accuracy.

Methods: This was a prospective observational study with a single centre derivation cohort and a second centre validation cohort. The derivation cohort included 49 naive PAH patients who underwent right heart catheterisation and echocardiographic evaluation at baseline and 4-12 months after diagnosis. The validation cohort included 83 prevalent PAH patients who underwent the same examinations at 12 months after diagnosis. We stratified the risk of the derivation cohort according to three models: Model 1, based on haemodynamic parameters; Model 2, based on standard echocardiographic parameters; and Model 3, based on advanced echocardiographic parameters. The median follow-up period was 21 months; the end point of the analysis was clinical worsening.

Results: In the derivation cohort, haemodynamic and echocardiographic parameters obtained at diagnosis were not associated with outcome, whereas a significant association was observed at first reassessment. Model 3 yielded a better predictive accuracy (Harrell's C index 0.832) as compared to Model 2 (Harrell's C index 0.667), and to Model 1 (Harrell's C index 0.713). The validation cohort confirmed the accuracy of Model 3.

Conclusions: A comprehensive assessment of right heart function using right ventricular strain, right atrial reservoir strain and degree of tricuspid regurgitation provides accurate prognostic information in prevalent PAH patients.

Risk stratification based on advanced echocardiographic parameters. The illustration depicts the comprehensive assessment of right ventricular pump function and of systemic venous congestion based on strain imaging parameters and on the degree of tricuspid regurgitation at re-evaluation. This approach is conforming with the haemodynamic approach recommended by international guidelines to stratify prognosis in PAH patients, based on the association of an indicator of pump function and an indicator of systemic venous congestion. RV: right ventricular; RA: right atrial; SVi: stroke volume index; RAP: right atrium pump; TR: tricuspid regurgitation; RAR: right atrial reservoir.

FIGURE 1

Risk stratification based on haemodynamic parameters at re-evaluation. Kaplan–Meier curves for low-, intermediate- and high-risk patients, defined on the basis of stroke volume index and right atrial pressure.

FIGURE 2

Risk stratification based on standard echocardiographic parameters at re-evaluation. Kaplan–Meier curves for low-, intermediate- and high-risk patients, defined on the basis of tricuspid annular plane systolic excursion, degree of tricuspid regurgitation and diameter of inferior vena cava.

FIGURE 3

Risk stratification based on advanced echocardiographic parameters in the validation cohort. Kaplan–Meier curves for low-, intermediate- and high-risk patients, defined on the basis of strain imaging parameters and on the degree of tricuspid regurgitation.