CONGRESS ABSTRACT

Background: Right ventricular–pulmonary arterial (RV–PA) coupling, expressed as the ratio of end-systolic to arterial elastance (Ees/Ea), is a key marker of RV efficiency and prognosis in advanced tricuspid regurgitation (TR). Non-invasive surrogates of coupling may help identify patients who could benefit from transcatheter tricuspid valve repair (TTVR). Methods: Forty-three symptomatic patients with at least severe TR referred for TTVR at Tampa General Hospital underwent comprehensive echocardiographic, computed tomographic, and invasive hemodynamic assessment. Pressure–volume (PV) loops were acquired using a conductance catheter (INCA®, CD Leycom) to determine Ees/Ea at end-expiration. Ea was calculated using both the conventional single-beat formula (Ea = end-systolic pressure/stroke volume) and the modified Brener equation. Correlations between invasive and echocardiographic indices (TAPSE/PASP, S′/PASP, RVFWLS/PASP, FAC/ESA, SV/ESA) and Ea and PASP/SVLV were analyzed using Spearman’s test and ROC curves. Results: Ea values derived from the Brener’s formula showed no correlation with invasive hemodynamic parameters, whereas significant associations were found when Ea was computed using the forward stroke volume (SV)–based method. SV and RV–PA coupling were markedly reduced, reflecting advanced VA uncoupling and maladaptation characterized by high afterload, poor contractile reserve, and inefficient energy transfer. Consistent with this advanced stage, only nine patients (20%) were ultimately treated with TTVR. Among echocardiographic surrogates, SV/ESA (r = 0.9, AUC 0.95, p < 0.0001) and FAC/ESA (r = 0.88, AUC 0.73, p < 0.0001) demonstrated the strongest correlations with invasive coupling, whereas TAPSE/PASP and S′/PASP were not significant. Conclusions: In patients with severe TR and advanced RV–PA uncoupling, volumetric indices such as SV/ESA and FAC/ESA most accurately reflect invasive coupling, whereas Doppler-based surrogates perform poorly. The Brener-derived Ea formula appears inapplicable in populations with pulmonary hypertension, supporting Tedford’s observations that its correction is appropriate only in physiologic coupling conditions.