Predictive value of non-invasive right ventricle to pulmonary circulation coupling in systemic lupus erythematosus patients with pulmonary arterial hypertension

Aims: Pulmonary arterial hypertension (PAH) is a serious and devastating complication of systemic lupus erythematosus (SLE), especially when the right ventricle (RV) fails. Whether the ratio between tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP) measured by echocardiography as a simple surrogate of RV to pulmonary circulation (PC) coupling predicts the outcome of SLE-associated PAH has not been investigated.

Methods and results: Between February 2010 and August 2015, 112 consecutive patients with a diagnosis of SLE-associated PAH confirmed by right heart catheterization were enrolled prospectively. The endpoint was a composite of all-cause mortality and clinical worsening. Baseline clinical characteristics and echocardiographic assessment were analysed. Among all the patients, 47 (42%) patients experienced the endpoint (mean follow-up period 18.1 ± 12.0 months), including 20 patients who died during a median follow-up period of 48.5 months. Multivariable Cox regression analysis showed that TAPSE/PASP ratio [hazard ratio (HR) 0.004, P = 0.017] and 6-min walk distance (6MWD) (HR 0.997, P = 0.036) were the independent predictors for the endpoint. A three-group prediction risk was created based on combined assessment of the TAPSE/PASP ratio and 6MWD relative to their cut-off values. The patients with the worse RV-PC coupling (TAPSE/PASP <0.184 mm/mmHg) and the lower 6MWD (<395 m) had the highest risk (HR 4.62, confidence interval 2.27-9.41, P < 0.001) of experiencing the endpoint.

Conclusion: The TAPSE/PASP ratio, combined with 6MWD, provides clinical and prognostic insights into patients with SLE-associated PAH. A low TAPSE/PASP and low 6MWD identifies the subgroup of patients with high risk of poor prognosis.