Discriminatory ability of right atrial volumes with two‐ and three‐dimensional echocardiography to detect elevated right atrial pressure in pulmonary hypertension

Summary Aims Pulmonary hypertension ( PH ) patients have high mortality due to right ventricular failure. Predictors of poor prognostic outcome are increased right atrial volume ( RAV ) and elevated mean right atrial pressure ( mRAP ). Our aim was to determine whether RAV measured with 2D echocardiography (2 DE ) and 3D echocardiography (3 DE ) can detect elevated mRAP in patients evaluated for PH. Methods Of 85 patients prospectively evaluated for PH , 44 patients (63 ± 15 years, 57% female) had 2 DE , 3 DE and right heart catheterization within 48 h and were in sinus rhythm. Maximum ( RAV max ) and minimum ( RAV min ) volumes were measured with 3 DE . 2D maximum RAV and RA area, inferior vena cava diameter and collapsibility were measured. Invasive mRAP  > 8 mmHg was predefined as elevated. Results RAV max and RAV min correlated with mRAP ( r  = 0·40 and r  = 0·35, P <0·05, for both), and so did 2 DE maximum RAV ( r  = 0·42, P  = 0·005) and RA area ( r  = 0·40, P  = 0·008). Area under the curve ( AUC ) from receiver‐operating characteristics curves was for 3 DE 0·77 for RAV max , 0·74 for RAV min , from 2 DE , 0·76 for maximum RAV and 0·75 for RA area to discriminate elevated mRAP ( P <0·01 for all). PH patients had larger 3D RAV compared with controls ( P <0·01). IVC diameter correlated with mRAP ( r  = 0·41, P  = 0·007), but collapsibility did not ( P  = 0·078). AUC was neither significant for IVC diameter nor for collapsibility for predicting mRAP >8 mmHg. The optimal threshold was 57 ml m −2 for RAV max , 31 ml m −2 for RAV min and 36 ml m −2 for 2DE RAV. Conclusions Enlarged RA measures with 2 DE and 3 DE have better discriminatory ability compared with IVC measures, to detect elevated mRAP in patients evaluated for PH .