Right atrial function index is an independent predictor of functional status in patients with pulmonary hypertension

Objectives: Right atrium (RA) plays an essential role in modulating right ventricular (RV) function. RA dysfunction is associated with poor survival in patients with pulmonary hypertension (PH). Right atrial function index (RAFI) which is defined as (RAEF×RVOT-VTI)/(RAVmax index) represents an easily obtainable echocardiographic variable of RA function assessment, synthesizing expressions of RA size, RA reservoir function and cardiac output. The purpose of our study was to evaluate RAFI and explore its association with functional status in PH subjects.Methods: A total of 63 PH patients were retrospectively studied. Patients were classified into high RAFI group and low RAFI group based on the median of RAFI. Echocardiography parameters of right heart dimension, RV overload, RV function and RA strain were assessed. Patients’ data of clinical characteristics were documented.Results: Elevated pulmonary arterial pressure, dilated RV dimension, RV overload and worsen cardiac function were observed in low RAFI group (P < 0.05). RAFI was significantly correlated with clinical and echocardiographic indices of pulmonary arterial pressure, pulmonary vascular resistance, RV dimension, RV overload and cardiac function (P < 0.05). In multivariable binary logistic regression analysis, RAFI independently predicted World Heart Organization functional class (WHO FC) III or IV (odds ratio = 0.847; 95% confidence interval, 0.722-0.994; P = 0.041). RAFI < 9.7 was the best cutoff to identify patients with WHO FC III or IV, with sensitivity of 70% and specificity of 79% (area under the curve = 0.777; 95% confidence interval, 0.660-0.894).Conclusions: RAFI provided an easy and valid alternative approach to evaluating RA function. RAFI showed correlation with most clinical and echocardiographic indices of right heart. RAFI was the independent determinant of WHO FC III or IV implying clinical deterioration.