Changes in renal function in congestive heart failure

Extending the ambit of SGLT2 inhibitors beyond diabetes: a review of clinical and preclinical studies on non-diabetic kidney disease

BACKGROUND

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are novel antidiabetic agents with overwhelming cardiorenal protection. Recent trials focusing on the nephroprotective role of SGLT2i have underscored its success as a phenomenal agent in halting the progression of kidney disease in patients with and without Type 2 diabetes mellitus. Multitudes of pleiotropic effects on tubules have raised hopes for reasonable nephroprotection beyond the purview of the hyperglycemic milieu.

AREA COVERED

This review summarizes various animal and human data as evidence for the utility of SGLT2i in non-diabetic chronic kidney disease (CKD). Web-based medical database entries were searched. On the premise of existing evidence, we have discussed mechanisms likely contributing to nephroprotection by SGLT2i in patients with non-diabetic CKD.

EXPERT OPINION

Further elucidation of mechanisms of nephroprotection offered by SGLT2i is required to extend its use as a nephroprotective agent. The use of non-traditional markers of kidney damage in future studies would improve the evaluation of their role in attenuating CKD progression. Emerging animal data support the early use of SGLT2i in states of modest proteinuria for superior outcomes. Future long-term trials in patients should aim to address the time of intervention with SGLT2i during the natural disease course of CKD for best outcomes.

Differential efficacy profile of aldosterone receptor antagonists, depending on the type of chronic heart failure, whether with reduced or preserved left ventricular ejection fraction-results of a meta-analysis of randomized controlled trials

BACKGROUND

Because of renin-angiotensin-aldosterone system (RAAS) activation, the patients with chronic heart failure (CHF) manifest increased ventricular stress, with impaired left ventricular function, and a slowing down in systemic venous drainage. More importantly, a reduction of the patient's life expectancy has been proven in the case of RAAS overstimulation. For these reasons, huge efforts have been made to obtain molecules able to efficaciously antagonize the RAAS overstimulation, such as aldosterone receptor antagonists (ARAs). These drugs have been shown to improve clinical outcomes in patients with heart failure with reduced left ventricular ejection fraction (HFREF), but not in those with preserved left ventricular ejection fraction (HFpEF). In order to study this topic more deeply, we carried out a meta-analysis of selective and nonselective ARAs in HFREF and HFpEF.

METHODS

Only randomized controlled trials (RCTs) were incorporated in our meta-analysis. Studies were included if they satisfied the following criteria: experimental groups included patients with CHF treated with ARAs in addition to the conventional therapy; control groups included patients with CHF receiving conventional therapy without ARAs. Outcomes of interest were all-cause mortality, cardiovascular hospitalizations, hyperkalemia, or gynecomastia.

RESULTS

Overall, 15 RCTs including a total of 15,671 patients were eligible for inclusion in the meta-analysis. ARA use in patients with heart failure was associated with a significant reduction in adverse outcomes. Indeed, a significant reduced odds of all-cause death among CHF patients treated with ARAs compared to controls was found [odds ratio (OR) =0.79; 95% CI: 0.73-0.87]. Subgroup analysis based on the heart failure (HF) type revealed a statistically significant benefit as regards all- cause death for patients with HFREF (OR =0.77; 95% confidence interval (CI): 0.69-0.84), but not for those with HFpEF (OR =0.91; 95% CI: 0.76-1.1). Furthermore reduced odds of CV hospitalizations was detected in the entire group of CHF patients under treatment with ARAs (OR =0.73; 95% CI: 0.61-0.89) as well as among HFREF patients treated with ARAs, compared to controls (OR =0.66; 95% CI: 0.51-0.85). Hyperkalemia was significantly more frequent with ARA use. Besides, ARA use was shown to be associated with the occurrence of gynecomastia. In particular, selective ARAs didn't induce significant amounts of gynecomastia compared to controls (OR =0.74; 95% CI: 0.43-1.27), while nonselective ARAs did (OR =8.22; 95% CI: 4.9-13.81).

CONCLUSIONS

Based on this meta-analysis, ARAs should be systematically used in patients with HFREF, in whom these drugs proved to reduce all-cause mortality and hospitalizations from cardiac cause. Conversely, ARA usage in HFpEF patients is questionable since in this CHF setting no significant improvement in clinical endpoints has been demonstrated so far. New selective ARAs are devoid of the risk of gynecomastia, while are similar to nonselective ARAs with regard to the efficacy profile as well as to the risk of eliciting hyperkalemia.

The Impact Exerted on Clinical Outcomes of Patients With Chronic Heart Failure by Aldosterone Receptor Antagonists: A Meta-Analysis of Randomized Controlled Trials

Background

Aldosterone receptor antagonists (ARAs) have been associated with improved clinical outcomes in patients with heart failure with reduced left ventricular ejection fraction (HFREF), but not in those with heart failure with preserved left ventricular ejection fraction (HFpEF). With the aim to study this topic more deeply, we carried out a meta-analysis of selective and non-selective ARAs in HFREF and HFpEF.

Methods

We searched PubMed and Scopus databases. We decided to incorporate in the meta-analysis only randomized controlled trials (RCTs) of ARAs in patients with chronic heart failure (CHF) if they met the following criteria: experimental groups included patients with CHF treated with ARAs in addition to the conventional therapy; control groups included patients with CHF receiving conventional therapy without ARAs. Outcomes of interest were all-cause death, hospitalizations from cardiovascular cause, hyperkalemia, or gynecomastia.

Results

We detected 15 studies representing 15,671 patients. ARAs were associated with a reduced odds of all-cause death (odds ratio (OR): 0.79; 95% confidence interval (CI): 0.73 - 0.87) and hospitalizations from cardiovascular cause (OR: 0.73; 95% CI: 0.61 - 0.89). However, subgroup analysis showed that these advantages were limited to HFREF (all-cause death: OR: 0.77, 95% CI: 0.69 - 0.84; hospitalizations from cardiovascular cause: OR: 0.66, 95% CI: 0.51 - 0.85), but they did not affect the HFpEF group (all-cause death: OR: 0.91, 95% CI: 0.76 - 1.1; hospitalizations from cardiovascular cause: OR: 0.85, 95% CI: 0.7 - 1.09). ARAs increased the risk of hyperkalemia (OR: 2.17; 95% CI: 1.88 - 2.5). Non-selective ARAs, but not selective ARAs, increased the risk of gynecomastia (OR: 8.22, 95% CI: 4.9 - 13.81 vs. OR: 0.74, 95% CI: 0.43 - 1.27).

Conclusions

ARAs reduced the risk of adverse cardiac events in HFREF but not HFpEF. In particular, ARA use in HFpEF patients is questionable, since in this CHF type, no significant improvement in all-cause death and cardiovascular hospitalizations was demonstrated with ARA treatment, in the face of the well-known risks of hyperkalemia and/or gynecomastia that chronic ARA therapy entails. Selective ARAs were equally effective as non-selective ARAs, without the risk of gynecomastia.

Type 4 cardiorenal syndrome

The Acute Dialysis Quality Initiative consensus conference proposed a classification of cardiorenal syndrome (CRS), aiming for a better delineation of each subtype. Although the exact pathophysiology of type 4 CRS is not completely understood, the mechanisms involved are probably multifactorial. There is growing evidence that oxidative stress is a major connector in the development and progression of type 4 CRS. Giving its complexity, poor prognosis and increasing incidence, type 4 CRS is becoming a significant public health problem. Patients with chronic kidney disease are particularly predisposed to cardiac dysfunction, due to the high prevalence of traditional cardiovascular risk factors in this population, but the contribution of risk factors specific to chronic kidney disease should also be taken into account. Much remains to be elucidated about type 4 CRS: despite progress over the last decade, there are still significant questions regarding its pathophysiology and there is as yet no specific therapy. A better understanding of the mechanisms involved may provide potential targets for intervention. The present review will provide a brief description of the definition, epidemiology, diagnosis, prognosis, biomarkers and management strategies of type 4 CRS, and the pathophysiological mechanisms and risk factors presumably involved in its development will be particularly highlighted.

Dipeptidyl Peptidase IV Inhibition Exerts Renoprotective Effects in Rats with Established Heart Failure

Circulating dipeptidyl peptidase IV (DPPIV) activity is associated with worse cardiovascular outcomes in humans and experimental heart failure (HF) models, suggesting that DPPIV may play a role in the pathophysiology of this syndrome. Renal dysfunction is one of the key features of HF, but it remains to be determined whether DPPIV inhibitors are capable of improving cardiorenal function after the onset of HF. Therefore, the present study aimed to test the hypothesis that DPPIV inhibition by vildagliptin improves renal water and salt handling and exerts anti-proteinuric effects in rats with established HF. To this end, male Wistar rats were subjected to left ventricle (LV) radiofrequency ablation or sham operation. Six weeks after surgery, radiofrequency-ablated rats who developed HF were randomly divided into two groups and treated for 4 weeks with vildagliptin (120 mg/kg/day) or vehicle by oral gavage. Echocardiography was performed before (pretreatment) and at the end of treatment (post-treatment) to evaluate cardiac function. The fractional area change (FAC) increased (34 ± 5 vs. 45 ± 3%, p < 0.05), and the isovolumic relaxation time decreased (33 ± 2 vs. 27 ± 1 ms; p < 0.05) in HF rats treated with vildagliptin (post-treatment vs. pretreatment). On the other hand, cardiac dysfunction deteriorated further in vehicle-treated HF rats. Renal function was impaired in vehicle-treated HF rats as evidenced by fluid retention, low glomerular filtration rate (GFR) and high levels of urinary protein excretion. Vildagliptin treatment restored urinary flow, GFR, urinary sodium and urinary protein excretion to sham levels. Restoration of renal function in HF rats by DPPIV inhibition was associated with increased active glucagon-like peptide-1 (GLP-1) serum concentration, reduced DPPIV activity and increased activity of protein kinase A in the renal cortex. Furthermore, the anti-proteinuric effect of vildagliptin treatment in rats with established HF was associated with upregulation of the apical proximal tubule endocytic receptor megalin and of the podocyte main slit diaphragm proteins nephrin and podocin. Collectively, these findings demonstrate that DPPIV inhibition exerts renoprotective effects and ameliorates cardiorenal function in rats with established HF. Long-term studies with DPPIV inhibitors are needed to ascertain whether these effects ultimately translate into improved clinical outcomes.

Variability in inpatient serum creatinine: its impact upon short- and long-term mortality

BACKGROUND

Long-staying medical inpatients carry a significant burden of acute and chronic illness. Prediction of their in-hospital and longer-term mortality risk is important.

AIM

The aim of this study was to determine to what extent creatinine variability predicts in-hospital and 1-year mortality in inpatients.

DESIGN

Retrospective cohort analysis.

METHODS

Patients were included if aged 18 years or older and if admitted for 7 days or longer. The main outcome variables were mortality in hospital and after discharge.

RESULTS

Increasing age, the presence of heart failure and a reduced estimated glomerular filtration rate (eGFR) on admission (<60 ml/min/1.73 m(2)) all associated with death risk (both in hospital and within a year of discharge). The creatinine change was related to mortality risk for the patient whilst in hospital and within 1 year after discharge independently of these other factors. The threshold of creatinine change, above which the in-hospital mortality rose significantly was 25 µmol/l (P < 0.001). A creatinine change of >10 µmol/l predicted significantly higher mortality within a year of discharge (P < 0.001). Every 5 µmol/l change in creatinine was associated with an in-hospital mortality increase of 3% (P < 0.001) and a 1-year mortality increase of 1% (P < 0.007).

CONCLUSIONS

Patients with a creatinine rise or fall of >10 µmol/l during admission are at higher risk of death after discharge than those with more stable creatinine. These patients therefore merit further attention that might include more focused nutritional assessment, cardiovascular risk factor management or advance care planning.