Echocardiographic Pulmonary to Left Atrial Ratio (ePLAR) as novel non-invasive parameter for elevated pulmonary vascular resistance in adults with unrepaired atrial septal defect

The accurate evaluation of pulmonary vascular resistance (PVR) is critical for evaluating operability and guiding management in adults with unrepaired atrial septal defect (ASD). Non-invasive echocardiographic markers, such as the echocardiographic Pulmonary to Left Atrial Ratio (ePLAR), calculated by dividing the peak tricuspid regurgitation velocity (TR Vmax) by the ratio of the transmitral E-wave to mitral annular e' velocity, may facilitate early risk stratification and reduce reliance on invasive procedures. Eighty-nine adult patients with unrepaired ASD underwent comprehensive echocardiography and right heart catheterization. ePLAR and additional echocardiographic parameters were measured, and their ability to identify elevated PVR (≥5 Wood Units, WU) was assessed through correlation and receiver operating characteristic (ROC) analysis. PVR ≥ 5 group showed elevated ePLAR (0.41 vs. 0.29, p  0.05). ePLAR is a practical, novel non-invasive echocardiographic parameter for identifying elevated pulmonary vascular resistance in adults with unrepaired ASD. With high sensitivity and independent predictive value, ePLAR is suitable for initial screening and risk stratification, potentially reducing unnecessary invasive testing and improving clinical decision-making.