Abstract
Background/Introduction
Intravascular volume is regulated by the kidneys but the interconnection of the extent of volume expansion with renal function and outcomes in patients with chronic HF has not been assessed. Therefore, we evaluated how GFR-defined renal function and HF-related clinical outcomes are impacted by the relative extent of intravascular volume expansion. Our hypothesis was that greater rather than lesser volume expansion would be protective of worse renal function and contribute to better clinical outcomes than mild-moderate volume expansion.
Purpose
Assess the impact of quantitated intravascular volume expansion on heart failure (HF) outcomes in relation to renal function in post-hospital clinically determined “euvolemic” chronic HF patients.
Methods
Blood volume (BV) was prospectively measured in 87 HF patients considered clinically “euvolemic” post-diuresis at the time of hospital discharge using a standardized radiolabeled albumin indicator-dilution technique (Daxor Corp., NY, NY). A volume cut-point of ≥+25% above normal expected BV was used to define the greater degree of volume expansion from more mild-moderate expansion. These volume subgroups were then stratified by cohort median eGFR (46 mL/min/1.73m2) and analyzed for 1-year outcomes of HF-related mortality or 1st re-hospitalization using the Kaplan-Meier method.
Results
Volume expansion ≥+25% was demonstrated in 53% of the cohort at the time of hospital discharge despite hospital diuretic therapy. In this subgroup over 1.0 year of follow-up the risk for the composite outcome was significantly lower than in the group with mild-moderate volume expansion (Log-Rank p=0.017). Further, in the clinical setting of greater volume expansion, worse renal function with eGFR below the cohort median (<46 mL/min/1.73m2) was not associated with increased risk for the composite end-point (Figure). In contrast, low eGFR in the presence of mild-moderate volume expansion stratified risk and was associated with worse outcome relative to a higher eGFR above the median (Figure).
Figure 1
Conclusions
In post-hospital chronic HF patients significant intravascular volume expansion is common, and importantly the extent of BV expansion impacts outcomes including HF-related mortality. However, greater rather than lesser volume expansion appears to favorably mitigate the impact of worse renal function (low eGFR), while normal or mild-moderate expansion does not spare the impact of worse renal function on outcomes. Thus, a favorable degree of volume expansion appears to balance the risks of worse renal function. Volume-kidney interconnections are complex with volume status modulating the impact of impaired renal function on outcomes in chronic HF.
Acknowledgement/Funding
None
Intravascular Volume Modulates the Outcome Predictive Capacity of Clinical Renal Function Biomarkers in Clinically “Euvolemic” Chronic Heart Failure Patients
