Right atrial function and prognosis in idiopathic pulmonary arterial hypertension

Aim: To determine whether right atrial (RA) function has prognostic value in patients with idiopathic pulmonary arterial hypertension (PAH).

Methods and results: Overall, 104 patients (70 female, mean age 58±13years) with idiopathic PAH underwent standard Doppler echocardiography and strain and strain rate (SR) analysis before right heart catheterization. At a mean follow-up of 22±7months, 30 patients (29%) had clinical worsening. On Cox multivariable proportional-hazards regression analysis, RA reservoir function measured as peak longitudinal SR (hazard ratio [HR] 0.5; P<0.0001), RA area (HR 1.2; P<0.01), right ventricular (RV) SR (HR 0.6; P<0.0001), cardiac index (HR 0.79; P<0.01), and mixed venous oxygen saturation (HR 0.82; P<0.01) were found to be independent correlates of cardiac events. A RA SR reservoir cut-off value of <1.2s^-1 and a RV SR cut-off value of <1s^-1 well identified patients at higher risk of clinical worsening (sensitivity 85.5%; specificity 90.4%; test accuracy 88.8%). In particular, event rates and mean survival time free of clinical worsening were: 6.1% and 23.5±2.2months in patients with normal RA and RV SR; 45% and 20.9±5.5months in patients with impaired RA and normal RV SR; 56.2% and 17.7±6.6months in patients with normal RA and impaired RV SR; and 87.5% and 12.9±7.6months in patients with impairment of both RA and RV SR.

Conclusion: Our data suggest that RA function has prognostic value in idiopathic PAH, where a poorer RA function, as explored by strain and SR analysis, is associated with a worse outcome.