New risk model by right ventricle - pulmonary arterial coupling and inferior vena cava from echocardiography in patients with conventional low-intermediate risk pulmonary artery hypertension under targeted treatment.

Background: Accurately stratifying patients with pulmonary arterial hypertension (PAH) is very important, and traditional risk scores still have internal heterogeneity. This study aimed to construct a risk stratification model that can accurately identify clinical worsening (CW) events in conventional low-intermediate risk patients with pulmonary hypertension under targeted drug treatment by using echocardiographic parameters.

Methods: This study is a single-center, prospective study, including 105 PAH patients who underwent regular follow-up at Guangdong Provincial People's Hospital from October 2021 to April 2023. The primary endpoint was the occurrence of CW, including death, hospitalization due to pulmonary hypertension, escalation of targeted drug therapy, and worsening of PAH. The predictive value of the echocardiography-based three-strata risk model was assessed using Kaplan-Meier curves and COX regression analysis.

Results: A total of 98 PAH patients were ultimately included in this study. The median follow-up duration was 26 months (range 7-28 months). The echocardiography-based three-strata model included the ratio of tricuspid annular plane systolic excursion and pulmonary artery systolic pressure (TAPSE/PASP) and inferior vena cava (IVC). The echocardiography-based three-strata model had higher diagnostic value (C-index = .76) compared to the 2022 ESC/ERS three-strata model and four-strata model (C-index = .66 and C-index = .61, respectively). PAH patients with lower TAPSE/PASP and wider IVC showed a higher CW rate compared to patients with higher TAPSE/PASP and normal IVC (HR = 15.1, 95%CI:4.4-51.9, p < .001).

Conclusion: The echocardiography-based three-strata model based on TAPSE/PASP and IVC can effectively improve the stratification of low-intermediate risk PAH patients under targeted treatment.