Early Detection of Arteriovenous Fistula Stenosis in Hemodialysis Patients through Routine Measurements of Dialysis Dose (Kt/V).

BACKGROUND: Monitoring of arteriovenous (AV) fistula to detect hemodynamically important stenosis is crucial for the prevention of AV fistula thrombosis. The aim of our study was to analyze the importance of dialysis dose (Kt/V) during online postdilution hemodiafiltration (HDF) for early detection of AV fistula stenosis. METHODS: Hemodialysis patients with AV fistula were included in this study. We compared a group of 44 patients who have undergone fistulography and subsequently percutaneous transluminal angioplasty (PTA) of significant AV fistula stenosis (active group) with a group of 44 age- and sex-matched patients without PTA (control group). Observational time in both groups was the same. RESULTS: All patients had postdilution online HDF using a F5008 dialysis machine, which can measure online single-pool Kt/V. All data were analyzed during the performance of 2056 HDF procedures. In the active group, we found statistically significantly lower values of Kt/V, all 8 weeks before PTA. In the active group, there was a significant improvement in Kt/V in the first (p < 0.001) and second week (p = 0.049) after PTA. Three and 8 weeks after PTA, we did not find any statistically significant difference in Kt/V between both groups (p = 0.114; p = 0.058). Patients in the active group had statistically significantly lower substitution volumes and blood pump flow rates during HDF over the whole observation period before and after PTA. In contrast, there were no differences in venous pressure in the dialysis circuit between both groups throughout the observation period. CONCLUSION: In hemodialysis patients with AV fistula, treated with online HDF, routine measurements of Kt/V during each HDF are a beneficial, quick, and straightforward method for early detection of hemodynamically significant AV fistula stenosis.

Assessment of volume status with bioimpendance prior to hemodialysis and its importance for predicting survival in hemodialysis patients.

BACKGROUND: Optimal fluid management is a physician's everyday challenge in patients on maintenance hemodialysis (HD). Bioimpedance spectroscopy (BIS) is a non-invasive method to estimate body composition, including estimates of fluid overload (FO). Our study aimed to analyze the association between FO and the mortality rate in HD patients. MATERIALS AND METHODS: We performed a retrospective single-center cohort study in 92 HD patients. The body composition was measured before HD using the portable whole-body BIS device Body Composition Monitor (BCM). We have analyzed the mortality rates of HD patients in two FO groups, a standard definition FO group (> 1.1 L), and a severe FO group (> 2.5 L) and compared them to mortality rates of patients without FO or without severe FO, respectively. RESULTS: The mean age of patients was 64.3 ± 13.0 years, mean dialysis vintage 64 months, 60.9% were men. 68 (73.9%) patients had FO of > 1.1 L and 30 (32.6%) had FO of > 2.5 L. During the follow-up period of 1,020 ± 417 days, 29 (31.5%) patients died. Kaplan-Meier survival analysis showed that patients with FO > 2.5 L had worse survival (p = 0.039). In a Cox regression model, which included FO > 2.5 L, age, dialysis vintage, hemoglobin, C-reactive protein, and albumin, only FO > 2.5 L and advanced age turned out to be predictors of death (p = 0.044 and p = 0.001, respectively). CONCLUSION: HD patients with FO > 2.5 L before HD have poorer survival than patients with normohydration or lower overhydration.

Relationship between subendocardial viability ratio and hemoglobin in patients with chronic kidney disease.

AIMS: Pulse wave analysis (PWA) uses the technique of applanation tonometry to obtain a peripheral pulse pressure waveform from which central hemodynamic information is derived. Using PWA, subendocardial viability ratio (SEVR) can be measured. SEVR represents a noninvasive measure of myocardial perfusion. It is related to the work of the heart, the oxygen consumption, and the energy supply of the heart. Anemia is a common complication of chronic kidney disease (CKD). A complex relationship exists between CKD, cardiovascular disease (CVD), and anemia. The aim of our study was to assess the relationship between SEVR and hemoglobin in non-dialysis CKD patients. MATERIAL AND METHODS: We examined the associations between PWA hemodynamic parameters, 24-hour ambulatory blood pressure (BP) measurements, and laboratory variables including hemoglobin, cardiac biomarkers troponin I, NT-proBNP, and hs-CRP in a cohort of 91 nondialysis CKD patients. PWA was assessed by radial applanation tonometry (SphygmoCor, Atcor, Sydney, Australia). The patients were divided into two groups according to the median value of hemoglobin. RESULTS: Mean age of included patients was 60.2 years, 67% were men, 44% were smokers, 25.3% had diabetes. A significant correlation between hemoglobin and SEVR was found (r = 0.26; p = 0.012). With multivariate regression analysis, SEVR as dependent variable turned out to be statistically significantly associated with hemoglobin (ß = 0.344, p = 0.013) and with troponin I (ß = -0.217, p = 0.037). Patients in the group with lower hemoglobin had statistically-significantly higher serum creatinine, cystatin C, NT-proBNP, and 24-hour ambulatory systolic BP and lower e-GFR, SEVR, and office diastolic BP. CONCLUSIONS: Results of our study show that SEVR is independently associated with hemoglobin in nondialysis CKD patients. CKD patients with lower hemoglobin have lower SEVR.
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Albuminuria is Associated With Subendocardial Viability Ratio in Chronic Kidney Disease Patients.

BACKGROUND/AIMS: Albuminuria is a well-established marker of subclinical organ damage. Pulse-wave analysis (PWA) employs the technique of applanation tonometry to obtain a peripheral pulse pressure waveform, from which central hemodynamic data are derived by application of the transfer function. Using PWA we can measure the subendocardial viability ratio (SEVR) and ejection duration (ED). SEVR or the Buckberg index is a non-invasive estimate of myocardial workload, oxygen supply and perfusion and a measure of the ability of the arterial system to meet the heart`s energy requirements. ED is the duration of ventricular ejection. The objective of this study was to evaluate the relationship between albuminuria and PWA parameters in chronic kidney disease (CKD) patients. METHODS: We studied 86 CKD patients aged 59.8±13.5 years, 56 (65.1%) were male. PWA analysis and 24-hour ambulatory blood pressure (24hABP) monitoring were performed. The following parameters were calculated: (1) aortic augmentation index with and without correction for a heart rate of 75 (Aix and AIx@ HR75), (2) SEVR, calculated as the ratio of the diastolic pressure time index and the systolic pressure time index, (3) ED, (4) estimated central aortic systolic and diastolic pressure and (5) central aortic pulse pressure calculated as the difference between estimated aortic systolic and diastolic BP. Blood samples and urine albumin-to-creatinine ratio (UACR) were analyzed; UACR values were natural log transformed (lnUACR). RESULTS: Using CKD-EPI creatinine-cystatin C formula the eGFR in patients was 7-130 ml/min/1.73 m² (mean 32.6; SD±24.6). We found statistically significant correlation between lnUACR and cystatin C (r=0.308; P=0.004), eGFR (r=-0.219; P=0.04), hemoglobin (r=-0.255; P=0.02), phosphorus (r=0.222; P=0.04), iPTH (r=0.268; P=0.01), SEVR (r=-0.254; P=0.02) and ED (r=0.315; P=0.003). No statistically significant correlations between lnUACR and cardiac biomarkers TnI, NT-proBNP, central aortic BP and 24h ABP values were found. Using multiple regression analysis statistically significant association was found between SEVR as dependent variable and lnUACR (ß=-0.223, P=0.039), sex (ß=-0.216, P=0.035), and diabetes (ß=0.332, P=0.001). Multiple regression analysis with ED as dependent variable has shown statistically significant association with lnUACR (ß=0.242, P=0.031) and diabetes (ß=-0.275, P=0.01). Patients were stratified into tertiles according to the lnUACR. Statistically significant differences in serum creatinine (P=0.001), cystatin C (P=0.012), hemoglobin (P=0.03), calcium (P=0.036), iPTH (P=0.008), SEVR (P=0.007) and ED (P=0.004) were found between tertiles. In post hoc analysis we found statistically significant differences between first and third tertile in SEVR (P=0.002; 95% CI:10.5-45) and in ED (P=0.001; 95% CI:-6.89-(-1.87)). CONCLUSIONS: Nondialysis CKD patients with higher levels of albuminuria have lower SEVR and higher ED and our results have shown the importance of central hemodynamic parameters like are SEVR and ED as a better or earlier noninvasive hemodynamic indexes in these patients.

Blood pressure measurements and left ventricular mass index in hemodialysis patients.

Left ventricular hypertrophy (LVH) is the most frequent cardiac abnormality in hemodialysis (HD) patients. It is related to cardiovascular diseases and is an important risk factor for mortality in HD patients. Arterial hypertension is an established risk factor for LVH in HD patients. Inferior vena cava (IVC) diameter is a good indicator of circulating fluid volume; hypervolemia is an important pathogenetic factor of hypertension in HD patients. The purpose of our study was to evaluate possible association between LVH, IVC diameter, and different blood pressure (BP) measurements in HD patients. In the present study, 85 HD patients were included. BP was measured with a standard mercury sphygmomanometer before and after the HD session; the average 1-monthly values of the routine BP measurements were also analyzed. 24- and 48-h ambulatory blood pressure measurements (ABPMs) were performed after the end of HD sessions using a noninvasive ABPM. Average values of systolic and diastolic BP were analyzed separately for the first (HD) and second (interdialytic) day ABPM and for both days together. Using echocardiography, left ventricular mass was measured and left ventricular mass index (LVMI) was calculated. Using ultrasonography, IVC diameter was measured on the interdialytic day. Using multiple regression analysis, we found statistically significant correlations between LVMI and mean monthly postdialysis systolic BP (P < 0.05) and mean 48-h diastolic BP (P < 0.05). Only longer BP measurements (average 1-month post-HD and 48-h ABPM) were associated with LVMI in HD patients.

Statin-Associated Necrotizing Myopathy Leading to Acute Kidney Injury: A Case Report.

Statins or 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors are a mainstay of cardiovascular disease therapy. In addition to their lipid-lowering capabilities, they exhibit several pleiotropic effects. Their adverse reactions such as myalgias are not uncommon, but in rare cases, the resulting rhabdomyolysis can be fatal. Recently, more insight has been brought into the pathogenesis of statin-induced rhabdomyolysis, and immune-mediated necrotizing myopathies are diagnosed more frequently. We present a case of a female patient who was on chronic rosuvastatin therapy and developed necrotizing myopathy. The disease progressed to acute kidney and liver injury. We discontinued the drug, started supportive measures, and initiated renal replacement therapy with a high cutoff dialysis membrane once. Her recovery was prompt, with a normal control electromyography 2 weeks after discharge.

The effect of high-flux hemodialysis and post-dilution hemodiafiltration on platelet closure time in patients with end stage renal disease.

INTRODUCTION: We aimed to compare prospectively the effect of high-flux hemodialysis and post-dilution hemodiafiltration on platelets. METHODS: Twenty-two hemodialysis patients were treated with one high-flux hemodialysis and one post-dilution hemodiafiltration procedure. PFA-100 closure times (collagen/epinephrine-CEPI and collagen/adenosine diphosphate-CADP) were measured before and after the procedure, as well as platelet count, hemoglobin, hematocrit, and red blood cell count. All pre-dialysis and post-dialysis samples were taken from the afferent line. FINDINGS: The platelet count after vs. before hemodialysis did not change significantly (229.3 ± 55.0 x109 /L vs. 233.6 ± 55.8 × 109 /L; P = 0.269), but was significantly lower after post-dilution hemodiafiltration (215.5 ± 51.7 × 109 /L vs. 245.3 ± 59.9 × 109 /L; P < 0.0001). CEPI after vs. before hemodialysis was not significantly prolonged (192.9 ± 60.8 s vs. 173.4 ± 52.5 s; P = 0.147), and the same applied to CADP (143.6 ± 40.3 s vs. 142.6 ± 38.4 s; P = 0.897). CEPI after vs. before post-dilution hemodiafiltration was significantly prolonged (268.3 ± 41.3 s vs. 176.4 ± 54.0 s; P < 0.0001) as was CADP (221.0 ± 53.9 s vs.133.9 ± 31.1 s; P < 0.0001). DISCUSSION: Only after post-dilution hemodiafiltration, we found a lower platelet count and prolonged platelet closure times.

Ankle-Brachial Index and Long-Term (10 Years) Survival of Nondiabetic Hemodialysis Patients.

Low (<0.9) and high (>1.4) ankle brachial index (ABI) is associated with a higher cardiovascular (CV) mortality in the general and hemodialysis (HD) population. The aim of our study was to determine the impact of ABI on long-term survival of 52 non-diabetic HD patients. The ABI was determined using an automated, non-invasive waveform analysis device. Patients were divided into three groups: low (<0.9), normal (0.9-1.4) and high (>1.4) ABI. Patients were observed from the date of ABI measurement until their death or ten years. Survival analysis showed higher risk for CV death in HD patients with high ABI compared to normal ABI (log rank test P < 0.027). In Cox regression model adjusted for arterial hypertension, smoking, serum cholesterol and triglycerides, high ABI (P < 0.049) remained a predictor of mortality. The results indicate an association between ABI and long-term survival of non-diabetic HD patients and only high ABI was associated with higher CV mortality.

[Sterile peritonitis after administration of icodextrin]. / Sterilni peritonitis nakon primjene ikodekstrina.

INTRODUCTION: Icodextrin is an 7.5% isoosmotic solution of the glucose polymer maltodextrin, recently frequently used in continuous ambulatory peritoneal dialysis (CAPD). It improves ultrafiltration and decreases glucose absorption. Among side effects of icodextrin, skin reactions and sterile peritonitis have been described. The authors present two cases of sterile peritonitis after icodextrin. CLINICAL PRESENTATION: In these two patients, the adverse events included peritoneal reaction to icodextrin solution. The reaction did not occur immediately after the initial administration of icodextrin, but after 70 (case 1) and 412 days (case 2) of regular use. This reaction to icodextrin solution resembled chemical peritonitis, however, the clinical picture was not absolutely typical of bacterial peritonitis either. Both patients had cloudy dialysate, elevated WBC in dialysate, no microorganisms were isolated, and no signs of allergic reaction could be detected. The clinical course was characterized by rapid remission upon isodextrin withdrawal. One patient received empiric antibiotic therapy, the other did not. Upon switching from icodextrin to glucose-based dialysate, the two patients were not challenged to icodextrin, and were doing well, without any symptoms of peritonitis. DISCUSSION AND CONCLUSION: The icodextrin solution contains an isoosmolar glucose polymer which allows longterm stable ultrafiltration. Among side effects, cutaneous reactions have been described (exfoliative, in the form of vesicles, psoriatic plaque or generalized exanthema in the form of pustules), which may occur in as many as 15% of patients. These symptoms and signs disappear upon discontinuation of icodextrin. Icodextrin side effects also include mild abdominal pain, allergic and hypersensitivity reactions, and recently sterile peritonitis. The patients described developed a clinical picture suggestive of chemical peritonitis. From the effluent no microorganisms were isolated, and the clinical picture was not absolutely typical of bacterial peritonitis either. Discontinuation of icodextrin was followed by immediate clearing of the effluents and normalization of WBC count.

Ascorbic Acid for the prevention of contrast-induced nephropathy after coronary angiography in patients with chronic renal impairment: a randomized controlled trial.

To determine the incidence of contrast-induced nephropathy (CIN) and to assess the effectiveness of ascorbic acid in the prevention of CIN after coronary angiography in patients with chronic renal impairment. CIN is the third most common cause of hospital-acquired renal failure. It is well documented that periprocedural hydration is effective in the prevention of CIN. Little data exist on the effectiveness of ascorbic acid, a vitamin with antioxidative action. Patients with stable serum creatinine level >107 µmol/L (n = 81) undergoing coronary angiography were randomized to receive either ascorbic acid (N = 40) or placebo (N = 41) before the procedure. All patients received intravenous volume expansion with normal saline before the procedure. CIN was defined as an increase of serum creatinine level >25% from baseline measured 3 to 4 days after the procedure. CIN occurred totally in 5/81 patients (6.2%); in two patients (3%) in the ascorbic acid group and in three patients (7.3%) in the placebo group (P = 0.512). Postprocedural worsening of renal function (postprocedural increase of serum creatinine level) was present in 10/81 patients (12.3%) in the ascorbic acid group and in 19/81 patients (23.4%) in the placebo group (P = 0.038). No patient required dialysis treatment. We found no statistically significant impact of ascorbic acid on the incidence of CIN in patients with chronic renal impairment undergoing coronary arteriography or angioplasty. Ascorbic acid may still have some protective role in CIN reflected in lower incidence of worsening of renal function in the treated group.

Ankle-brachial index and cardiovascular mortality in nondiabetic hemodialysis patients.

Atherosclerosis is a leading cause of morbidity and mortality in hemodialysis (HD) patients. Low (<0.90) and high (>1.40) ankle-brachial index (ABI) is known as a non-invasive diagnostic marker for generalized atherosclerosis associated with higher cardiovascular (CV) mortality in the general population. Less is known about associations between ABI and CV mortality in HD patients. The aim of our study was to determine the impact of the ABI on CV mortality in nondiabetic HD patients. Fifty-two nondiabetic HD patients (mean age 59 years, range 22 - 76 years) were enrolled in our study. Twenty-three (44%) were women and 29 (56%) men. The ABI was determined using an automated, non-invasive, waveform analysis device. All patients were divided according to the ABI into three groups: low ABI (<0.9), normal ABI (0.9-1.4) and high ABI (>1.4). The presence of arterial hypertension and smoking was established. Serum cholesterol (HDL and LDL) and triglycerides were measured by routine laboratory methods. Survival rates were analyzed using Kaplan-Meier survival curves. The Cox regression model was used to assess the influence of the ABI on CV outcomes. The model was adjusted for age, arterial hypertension, smoking, cholesterol and triglycerides. Mean ABI value was 1.2 ± 0.3 (range 0.2-2.2). Patients were observed from the date of the ABI measurement until their death or maximally up to 1620 days. Kaplan-Meier survival analysis showed that the risk for CV death was higher for HD patients with low and high ABI compared to normal ABI (log rank test: P < 0.006; P < 0.0001). In the adjusted Cox multivariable regression model low and high ABI (P < 0.011; P < 0.003) remained predictors of mortality in our patients. The results indicate a U-shaped association between the ABI and CV mortality in nondiabetic HD patients and showed that low and high ABI were directly associated with higher mortality of our patients.

Blood pressure measurements and carotid intima media thickness in hemodialysis patients.

In hemodialysis (HD) patients, routine dialysis center blood pressure (BP) measurements may be a poor indicator of BP control. Ambulatory blood pressure monitoring (ABPM) improves the predictability of BP as a risk factor for target organ damage. Carotid intima-media thickness (IMT) is an important indicator of asymptomatic atherosclerosis and a predictor of cardiovascular events. The purpose of our study was to evaluate the possible association between different BP measurements and carotid IMT in HD patients. Eighty-five HD patients were included in our study. BP was measured with a standard mercury sphygmomanometer before and after each HD session. The average one-monthly values of routine BP measurements were also analyzed. 24- and 48-h ABPM was performed after the end of each HD session using non-invasive ABPM. The average values of systolic and diastolic BP were analyzed separately for the first (HD) and second (interdialytic) days ABPM, and for both days together. Using B-mode ultrasonography, carotid IMT was measured and plaque occurrence investigated. We found a statistically significant correlation between carotid IMT and the average one-monthly pre-HD diastolic BP (P < 0.05), diastolic BP on the HD-day ABPM, the interdialytic-day ABPM, and during 48-h ABPM (P < 0.05). By multiple regression analysis, we found a statistically significant correlation only between carotid IMT and diastolic BP on the HD-day ABPM, the interdialytic-day ABPM, and during 48-h ABPM (P < 0.05). Only longer BP measurements (24- and 48-h ABPM) were associated with carotid IMT in HD patients.

Homocysteine and vascular access thrombosis in hemodialysis patients.

BACKGROUND: Vascular access remains the Achilles' heel of successful hemodialysis, and thrombosis is the leading cause of vascular access failure. Hyperhomocystinemia is common in hemodialysis patients and is associated with venous and arterial thrombosis in patients without end-stage renal disease. SUBJECTS AND METHODS: In the study, 65 hemodialysis patients with native arteriovenous fistula were included. Two groups of patients were defined: group A including 45 patients with their vascular access either never or only once thrombosed, and group B including 20 patients with two or more thromboses of their vascular access. We determined serum concentrations of total homocysteine (immunoassay, Abbott) in our patients. RESULTS: In 63 (96.9%) patients, hyperhomocystinemia was presented. There was no statistically significant difference between group A and B regarding age, gender and duration of hemodialysis treatment. Total homocysteine concentrations were higher in group A (42.1 +/- 18.6 micromol/l) than in group B (36.1 +/- 18.1 micromol/l) patients but the difference was small and not statistically significant. CONCLUSION: We found no significant differences in total homocysteine concentrations between group A (thrombosis non-prone) and group B (thrombosis prone) patients. Our results suggest that thrombosis of native arteriovenous fistulas may not be caused by hyperhomocystinemia in these patients.