Importance of anemia in the chronic Cardiorenal syndrome: effects on renal function after heart transplantation

Left ventricular assist devices: a kidney's perspective

The left ventricular assist device (LVAD) has become an established treatment option for patients with refractory heart failure. Many of these patients experience chronic kidney disease (CKD) due to chronic cardiorenal syndrome type II, which is often alleviated quickly following LVAD implantation. Nevertheless, reversibility of CKD remains difficult to predict. Interestingly, initial recovery of GFR appears to be transient, being followed by gradual but significant late decline. Nevertheless, GFR often remains elevated compared to preimplant status. Larger GFR increases are followed by a proportionally larger late decline. Several explanations for this gradual decline in renal function after LVAD therapy have been proposed, yet a definitive answer remains elusive. Mortality predictors of LVAD implantation are the occurrence of either postimplantation acute kidney injury (AKI) or preimplant CKD. However, patient outcomes continue to improve as LVAD therapy becomes more widespread, and adverse events including AKI appear to decline. In light of a growing destination therapy population, it is important to understand the cumulative effects of long-term LVAD support on kidney function. Additional research and passage of time are required to further unravel the intricate relationships between the LVAD and the kidney.

Renal perfusion index reflects cardiac systolic function in chronic cardio-renal syndrome

BACKGROUND

Cardiac dysfunction can modify renal perfusion, which is crucial to maintain sufficient kidney tissue oxygenation. Renal cortex perfusion assessed by dynamic ultrasound method is related both to renal function and cardiac hemodynamics. The aim of the study was to test the hypothesis that Renal Perfusion Index (RPI) can more closely reflect cardiac hemodynamics and differentiate etiology of chronic cardio-renal syndrome.

MATERIAL AND METHODS

Twenty-four patients with hypertension and chronic kidney disease (CKD) at 2-4 stage (12 with hypertensive nephropathy and 12 with CKD prior to hypertension) were enrolled in the study. Blood tests, 24-h ABPM, echocardiography, and ultrasonography with estimation of Total renal Cortical Perfusion intensity and Renal Perfusion Index (RPI) were performed.

RESULTS

In the group of all patients, RPI correlated with left ventricular stoke volume (LVSV), and cardiac index, but not with markers of renal function. In multiple stepwise regression analysis CKD-EPI(Cys-Cr) (b=-0.360), LVSV (b=0.924) and MAP (b=0.376) together independently influenced RPI (R2=0.74; p<0.0001). RPI<0.567 allowed for the identification of patients with chronic cardio-renal syndrome with sensitivity of 41.7% and specificity of 83.3%.

CONCLUSIONS

Renal perfusion index relates more strongly to cardiac output than to renal function, and could be helpful in recognizing chronic cardio-renal syndrome. Applicability of RPI in diagnosing early abnormalities in the cardio-renal axis requires further investigation.

Combination of hemoglobin and left ventricular ejection fraction as a new predictor of contrast induced nephropathy in patients with non-ST elevation myocardial infarction

BACKGROUND

Hemoglobin concentration (Hb) and left ventricular ejection fraction (EF) are known predictors of contrast induced nephropathy (CIN). We hypothesized that combination of Hb concentration and left ventricular EF is superior to either variable alone in predicting contrast induced nephropathy in patients with acute coronary syndrome (ACS).

MATERIAL AND METHODS

Consecutive patients with ACS were prospectively enrolled. Patients considered for invasive strategy were included. Baseline creatinine levels were detected on admission and 24, 48 and 72 hours after coronary intervention. 25% or 0,5 umol/L increase in creatinine level was considered as CIN.

RESULTS

268 patients with ACS (mean age 58±11 years, 77% male) were enrolled. Contrast induced nephropathy was observed in 26 (9.7%) of patients. Baseline creatinine concentration, left ventricular EF, and Hemoglobin was significantly different between two groups. Contrast volume to estimated glomerular filtration rate ratio (OR: 1.310, 95% CI: 1.077-1.593, p=0.007) and the combination of Hb and left ventricular EF (OR: 0.996, 95% CI: 0.994-0.998, p=0.001) were found to be independent predictors for CIN. Hb × LVEF ≤690 had 85% sensitivity and 57% specificity to predict CIN (area under curve: 0.724, 95% CI: 0.625-0.824, p<0.001). In addition, Hb × LVEF ≤690 had a negative predictive value of 97% in our analysis

CONCLUSIONS

The combination of Hb and left ventricular EF is better than either variable alone at predicting CIN in patients with ACS that undergone percutaneous coronary intervention. The prediction was independent of baseline renal function and volume of contrast agent.

Effect of methoxy polyethylene glycol-epoetin beta on oxidative stress in predialysis patients with chronic kidney disease

Background

There is data in the literature indicating increased oxidative stress in chronic kidney disease (CKD). Erythropoiesis-stimulating agents (ESAs), which are commonly used to treat anemia in patients with CKD, seem to have an antioxidant action, which could be a part of nephroprotection. The aim of the current study was to investigate the effect of a long half-life ESA, methoxy polyethylene glycol-epoetin beta (Mircera), on some markers of oxidative stress in predialysis patients with CKD.

Material/Methods

Peripheral blood was collected from 28 predialysis CKD patients 2 times, before Mircera treatment and after achieving target hemoglobin (Hb), and 15 healthy subjects (control group). Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activity in erythrocytes were measured according to commonly used methods as a function of the antioxidant defense system. To assess reactive oxygen species (ROS) production, malondialdehyde (MDA) concentration in erythrocytes and in plasma was measured according to a commonly used method.

Results

SOD, GSH-Px, and CAT activity were similar, but plasma and erythrocyte MDA concentrations were significantly higher in CKD patients before ESA treatment in comparison to the control group. SOD, GSH-Px, and CAT activity was significantly higher, but plasma and erythrocyte MDA concentrations were significantly lower, in CKD patients after ESA treatment in comparison to these patients before treatment. We did not find a significant correlation between Hb concentration and SOD, GSH-Px, and CAT activity and plasma, as well as erythrocyte MDA concentrations. Analysis of all investigated groups showed a significant negative correlation between Hb concentration and plasma MDA concentration.

Conclusions

Our results suggest that treatment of anemia with methoxy polyethylene glycol-epoetin beta may inhibit oxidative stress in predialysis patients with CKD by enhancing the antioxidant defense system and reducing ROS production.