Biochemical evidence of mild hepatic dysfunction identifies decompensated heart failure patients with reversible renal dysfunction

Evidence of Mild Liver Dysfunction Identifies Stable Heart Failure Outpatients with Reversible Renal Dysfunction

BACKGROUND

In decompensated heart failure (HF), reversible renal dysfunction (RD) is more frequently observed in patients with mild liver dysfunction likely due to the shared pathophysiologic factors involved. The objective of this study was to determine if these findings also apply to stable HF outpatients.

METHODS

Patients in the Beta-Blocker Evaluation of Survival Trial (BEST) were studied. Improvement in renal function (IRF) was defined as a 20% improvement in the estimated glomerular filtration rate from baseline to 3 months.

RESULTS

Elevated bilirubin (BIL), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were significantly associated with signs of congestion or poor perfusion. IRF occurred in 12.0% of all patients and was more common in those with elevated BIL (OR = 1.5, p = 0.003), ALT (OR = 1.4, p = 0.01), and AST (OR = 1.4, p = 0.01). In a model containing all 3 liver parameters and baseline characteristics, including markers of congestion/poor perfusion, BIL (OR = 1.6, p = 0.001) and ALT (OR = 1.7, p < 0.001) were independently associated with IRF.

CONCLUSIONS

Biochemical evidence of mild liver dysfunction is significantly associated with IRF in stable HF outpatients. Given the widespread availability and low cost of these markers, additional research is necessary to determine the utility of these parameters in identifying patients with reversible RD who may benefit from cardiorenal interventions.

Novel renal biomarkers to assess cardiorenal syndrome

Renal dysfunction (RD) in heart failure portends adverse outcomes and often limits aggressive medical and decongestive therapies. Despite the high prevalence in this population, not all forms of RD are prognostically or mechanistically equivalent: RD can result from irreversible nephron loss secondary to diabetic or hypertensive kidney disease or it can develop secondary to heart failure (HF) itself, i.e., the cardiorenal syndrome. Furthermore, filtration is only one aspect of renal performance such that significant renal impairment secondary to cardiorenal syndrome can exist despite a normal glomerular filtration rate. Renal biomarkers have the potential to inform some of the intricacies involved in accurately assessing cardiorenal interactions. This article discusses novel biomarkers for cardiorenal syndrome and their utility in the prognosis, diagnosis, and targeted treatment of heart failure-induced RD.

A patient with heart failure and worsening kidney function

There is high prevalence of CKD, defined by reduced GFR, in patients with heart failure. Reduced kidney function is associated with increased morbidity and mortality in this patient population. The cardiorenal syndrome (CRS) involves a bidirectional relationship between the heart and kidneys whereby dysfunction in either may exacerbate the function of the other, but this syndrome has been difficult to precisely define because it has many complex physiologic, biochemical, and hormonal abnormalities. The pathophysiology of CRS is not completely understood, but potential mechanisms include reduced kidney perfusion due to decreased forward flow, increased right ventricular and venous pressure, and neurohormonal adaptations. Treatment options include inotropic medications; diuretics; ultrafiltration; and medications, such as β-blockers, inhibitors of the renin-angiotensin-aldosterone system, and more novel treatments that focus on unique aspects of the pathophysiology. Recent observational studies suggest that treatments that result in a decrease in venous pressure and lead to hemoconcentration may be associated with improved outcomes. Patients with CRS that is not responsive to medical interventions should be considered for ventricular assist devices, heart transplantation, or combined heart and kidney transplantation.