Introduction:
Chronic heart failure (CHF) and impaired renal function are two co-existing medical conditions and known to be associated with adverse outcome. The cardiorenal interaction has not yet been analyzed thoroughly. The aim of this study was to assess renal and intraglomerular hemodynamics by constant infusion input clearance technique in subjects with CHF compared to healthy controls.
Methods:
This was a cross-sectional observational study including 85 subjects. The group of subjects with CHF consisted of 27 individuals with HFpEF and 27 individuals with HFrEF, who were compared to 31 controls. All subjects underwent renal clearance examination to determine measured -not estimated- glomerular filtration rate (GFR), renal blood and plasma flow (RBF, RPF) and to calculate renal hemodynamic parameters such as filtration fraction (FF), renal vascular resistance (RVR), intraglomerular pressure (P
glom
) and resistances of the afferent (R
A
) and efferent arterioles (R
E
).
Results:
GFR was lower in subjects with CHF (88.6±13.1ml/min/1.73m
2
) compared to controls (108.6±17. ml/min/1.73m
2
) after adjustment for age and BP (p
adj
=0.037). There were no significant differences regarding RPF, RBF, FF, RVR, P
glom
, R
A
as well as R
E
after adjustment for age and BP. Similarly, there were no significant differences regarding renal hemodynamic parameters between HFpEF and HFrEF subjects. Bivariate correlation analysis in the group of subjects with CHF revealed an inverse association between NT-proBNP and RPF (R=-0.421, p=0.002), RBF (R=-0.414, p=0.002) and a positive association with FF (R=0.324, p=0.019), RVR (R=0.346, p=0.012) and R
E
(R=0.318, p=0.022).
Conclusions:
The findings of this study indicate that in CHF renal function is slightly reduced even though renal perfusion is preserved. With progressive severity of CHF as indicated by increasing NT-proBNP, renal vascular resistance in particular at the postglomerular side increases. Our data are in accordance with neuroendocrine activation in CHF since vasoconstriction at the postglomerular site points towards angiotensin II as mediator. The association between NT-proBNP and renal hemodynamics documents a close cardiorenal interaction in CHF.
Intermittent Hypoxia Adversely Affects Renal Hemodynamics and Oxygen Flux in Chronic Heart Failure
