Effect of Transcatheter Aortic Valve Replacement on Right Ventricular-Pulmonary Artery Coupling

Abstract

Objectives: The aim of this study was to test the hypothesis that the acute left ventricular (LV) unloading effect of transcatheter aortic valve replacement (TAVR) would improve right ventricular (RV) function and RV-pulmonary artery (PA) coupling in patients with severe aortic stenosis (AS).

Background: RV dysfunction is an ominous prognostic marker in patients undergoing TAVR, suggesting that relief of obstruction might be less beneficial in this cohort. However, the left ventricle and right ventricle influence each other through ventricular interaction, which could lead to improved RV function through LV unloading.

Methods: Prospective invasive hemodynamic measurements with simultaneous echocardiography were performed in symptomatic patients with severe AS before and immediately after TAVR.

Results: Forty-four patients (mean age 81 ± 8 years, 27% women) with severe AS underwent TAVR. At baseline, right atrial, PA mean (27 ± 7 mm Hg), and pulmonary capillary wedge (16 ± 4 mm Hg) pressures were mildly elevated, with a low normal cardiac index (2.3 l/min/m²). Pulmonary vascular resistance was mildly elevated (222 ± 133 dynes · s/cm⁵) and PA compliance mildly reduced (3.4 ± 01.4 ml/mm Hg). Following TAVR, aortic valve area increased (from 0.8 ± 0.3 to 2.7 ± 1.1 cm²; p < 0.001) with a reduction in mean aortic gradient (from 37 ± 11 to 7 ± 4 mm Hg; p < 0.001) and an increase in cardiac index (from 2.3 ± 0.5 to 2.5 ± 0.6 l/min/m²; p = 0.03). LV stroke work, end-systolic wall stress, and systolic ejection period decreased by 23% to 27% (p < 0.001 for all), indicating substantial LV unloading. RV stroke work (from 16 ± 7 to 18 ± 7 mm Hg · ml; p = 0.04) and tricuspid annular systolic velocities (from 9.5 ± 2.0 to 10.4 ± 3.5 cm/s; p = 0.01) increased, along with a decrease in PVR (194 ± 113 dynes · s/cm⁵; p = 0.03), indicating improvement in RV-PA coupling. Increased RV stroke work following TAVR directly correlated with the magnitude of increase in aortic valve area (r = 0.58; p < 0.001).

Conclusions: Acute relief in obstruction to LV ejection with TAVR is associated with improvements in RV function and RV-PA coupling. These findings provide new insights into the potential benefits of LV unloading with TAVR on RV dysfunction in patients with severe AS.

Keywords: aortic stenosis; pulmonary vascular function; right ventricular function; transcatheter aortic valve replacement.