Quantitative fluid overload in severe aortic stenosis refines cardiac damage and associates with worse outcomes

Abstract

Abstract Background Cardiac decompensation in aortic stenosis (AS) involves extra-valvular cardiac damage (CD) and progressive fluid overload (FO). FO can be objectively quantified using bioimpedance spectroscopy (BIS). Objectives We aimed to assess the prognostic value of FO beyond established CD markers to guide risk stratification. Methods Consecutive patients with severe AS scheduled for transcatheter aortic valve implantation (TAVI) underwent prospective risk assessment with BIS and echocardiography. FO by BIS was defined as ≥1.0L (0.0L=euvolemia). The extent of CD was assessed by echocardiography according to an established staging classification. Right-sided CD (rCD) was defined as pulmonary vasculature/tricuspid/right ventricular CD. Heart failure hospitalization (HHF) and/or death served as primary endpoint. Results In total, 880 patients (81±7y/o, 47% female) undergoing TAVI were included. 360 (41%) had FO. Clinical examination in patients with FO was unremarkable for congestion signs in >50%. A quarter had FO but no rCD (FO+/rCD-). FO+/rCD+ had the highest CD markers, including NT-proBNP levels. After 2.4±1.0 years of follow-up, 236 patients (27%) had reached the primary endpoint (29 HHF, 194 deaths, 13 both). Quantitatively, every 1.0L increase in BIS was associated with a 12% increase in event hazard (adjHR 1.12, 95% CI 1.05-1.20, P=0.001). FO provided incremental prognostic value to traditional risk markers (NT-proBNP, EuroSCORE-II, CD on echocardiography). Stratification according to FO and rCD yielded worse outcomes for FO+/rCD+ and FO+/rCD-, but not FO-/rCD+, compared to FO-/rCD-. Conclusion Quantitative FO in patients with severe AS improves risk prediction of worse post-interventional outcomes compared to traditional risk assessment.