3D echo derived right ventricular principal surface strain in pulmonary arterial hypertension

Traditional echocardiographic metrics of right ventricular (RV) function, including tricuspid annular plane systolic excursion and two-dimensional (2-D) strain, are limited to the description of longitudinal systolic function. These metrics, however, fail to account for the complex, three-dimensional (3-D) deformation of the RV. 3-D echocardiograms (3DE) were obtained simultaneously during clinically indicated right heart catheterization (RHC). We determined the maximum principal surface strain (PS_Max) and angle (ϴ_Max) of RV surface deformation in pulmonary arterial hypertension (PAH) and control patients. We compared 22 control patients to 37 patients with PAH, of whom 11 met hemodynamic criteria for right heart (RH) failure. Compared with 2-D descriptors of RV function, PS_Max was significantly different between controls and patients with PAH and between PAH patients with and without RH failure. ϴ_Max was progressively oriented longitudinally in PAH patients without RH failure compared to PAH patients with RH failure [37.5° (34.3° to 40.8°) vs. 34.3° (32.1° to 36.2°), <i>P</i> = 0.042] and in PAH patients with worse New York Heart Association functional class. Thirty-day outcomes were significantly different with an optimal cutoff of PS_Max of -21.4%, with a hazard ratio of 6.8 (95% CI 1.3 to 35.2, <i>P</i> = 0.022). PS_Max is a robust marker of RH failure and provides prognostic value in PAH beyond conventional 2-D descriptors of RH function. Progressive longitudinal deformation of ϴ_Max is associated with worse RH function and functional class.<b>NEW & NOTEWORTHY</b> Impaired PS_Max is associated with worse RV systolic function and outcomes in PAH when compared with conventional 2-D metrics of RV systolic function, while ϴ_Max is progressively oriented longitudinally in PAH patients with RH failure compared to those without RH failure, potentially reflecting an echocardiographic representation of maladaptive RV myofiber reorientation. PS_Max and ϴ_Max represent a powerful and concise way to describe RV systolic function that may prove useful in the care of PAH patients.