Physiological and Clinical Consequences of Right Ventricular Volume Overload Reduction After Transcatheter Treatment for Tricuspid Regurgitation

OBJECTIVES This study sought to examine the impact of chronic right ventricular (RV) volume overload and implications of tricuspid regurgitation (TR) reduction on biventricular function. BACKGROUND Severe TR is a major determinant of adverse outcomes in advanced heart failure patients. The understanding of TR pathophysiology and implications of correction is still limited. Transcatheter tricuspid edge-to-edge repair (TTVR) is a new treatment option in patients at high surgical risk and provides a unique pathophysiological model without confounding effects of cardiac surgery. METHODS Twenty-nine patients (78 +/- 4 years of age) with severe isolated TR and high surgical risk underwent TTVR using the MitraClip system, and of these 18 underwent repeated cardiac magnetic resonance. Clinical follow-up was realized at 1 and 6 months after the intervention. RESULTS TR fraction was reduced from 41% to 21% (p < 0.01) without increase in RV afterload (p = 0.52) and RV end-diastolic volume (p < 0.01), and RV stroke volume decreased (p = 0.03), whereas RV effective forward flow increased (p = 0.03). Left ventricular (LV) filling improved with an increase in LV end-diastolic volume (p = 0.01) and LV stroke volume (p = 0.02), leading to an augmentation of cardiac indices (2.2 +/- 0.6 l/min/m(2) vs. 2.7 +/- 0.6 l/min/m(2); p < 0.01) with similar results at 6 months follow-up. After TTVR, New York Heart Association functional class significantly improved (p < 0.01), peripheral edema decreased (p = 0.01), and 6-min walk distance increased by 20% and 22% after 1 and 6 months, respectively (p < 0.01). CONCLUSIONS TTVR reduces chronic RV volume overload without increase in RV afterload, improves RV performance and LV filling, and enhances cardiac output. These changes translate into symptomatic and functional improvement. These implications for biventricular physiology and clinical status are maintained at 6 months follow-up. (C) 2019 by the American College of Cardiology Foundation.