Age-Stratified Performance of the TAPSE/sPAP Ratio as a Marker of Right Ventricular-Pulmonary Arterial Coupling in Chronic Kidney Disease

Abstract

Background Right ventricular (RV) dysfunction in chronic kidney disease (CKD) remains underrecognized. The tricuspid annular plane systolic excursion to systolic pulmonary artery pressure ratio (TAPSE/sPAP) reflects RV-pulmonary arterial coupling, but its relationship with CKD severity is unknown. To evaluate the association between TAPSE/sPAP ratio and CKD stage severity and assess age-related effect modification. Methods This cross-sectional study enrolled 120 participants: 40 patients with stage I-II CKD, 40 with stage III-IV CKD, and 40 healthy controls. All underwent echocardiography and nephrologist evaluation. Proportional odds regression models adjusted for cardiovascular risk factors evaluated the TAPSE/sPAP-CKD association. ROC analysis assessed discriminatory performance. Age-stratified analyses (<65 vs. >= 65 years) evaluated effect modification. Results TAPSE/sPAP ratio declined progressively across CKD stages (controls: 0.67 +/- 0.11, stage I-II: 0.61 +/- 0.13, stage III-IV: 0.53 +/- 0.13 mm/mmHg; p < 0.01). Each 0.10-unit decrease was independently associated with advanced CKD (adjusted OR 2.08, 95% CI 1.49-2.89, p < 0.001). TAPSE/sPAP ratio achieved the highest AUC (0.734, 95% CI 0.625-0.833), outperforming TAPSE alone (AUC 0.615; DeLong p = 0.049), while statistically comparable to sPAP (AUC 0.715; DeLong p = 0.400). Age-stratified analysis revealed excellent performance in patients <65 years (AUC 0.819, sensitivity 78.6%, specificity 86.8%) but limited utility in those >= 65 years (AUC 0.579; p = 0.015). Random forest analysis identified age (35.8%) and TAPSE/sPAP (22.0%) as dominant predictors. Conclusions TAPSE/sPAP ratio is an independent marker of CKD severity enabling non-invasive detection of RV-PA uncoupling, with excellent discriminatory performance in younger but limited utility in older patients, suggesting that age-specific interpretation and integration with renal biomarkers are recommended.