Stressed Blood Volume in Severe Tricuspid Regurgitation: Implications for Transcatheter Treatment

Background: Although tricuspid transcatheter edge-to-edge repair (TEER) has been suggested to improve outcomes in patients with tricuspid regurgitation (TR), patients remain at substantial residual risk after the intervention. Total blood volume is divided between the unstressed volume, filling the vascular space, and stressed blood volume (SBV), generating intravascular pressure. SBV is an important mediator of hemodynamic derangements in heart failure and might pose an attractive adjunctive treatment target.

Objectives: The aim of this study was to investigate the role of SBV in patients with severe TR and its implications for tricuspid TEER.

Methods: In total, 279 patients underwent right heart catheterization prior to TEER. SBV was estimated from hemodynamic variables fit to a comprehensive cardiovascular model.

Results: Estimated stressed blood volume (eSBV) was associated with obesity, renal and hepatic dysfunction and cardiac remodeling (P < 0.05 for all). Hemodynamically, eSBV correlated with pulmonary artery and cardiac filling pressures as well as right ventricular-pulmonary artery coupling (P < 0.05 for all). After TEER, patients with eSBV greater than the median demonstrated less reduction in right atrial pressures, peripheral edema, and ascites compared with lower eSBV patients (P < 0.05 for all). Higher eSBV was an independent predictor of the occurrence of death and heart failure hospitalization during a median follow-up duration of 618 days (P < 0.05 for all).

Conclusions: In patients with severe TR, eSBV is associated with obesity, renal and liver dysfunction, more severe heart failure, attenuated reduction of venous congestion after TEER, and adverse clinical outcomes. Estimation of SBV should be incorporated in future trials in the field to identify patients in need of adjunctive therapies.