Randomized trial of bioelectrical impedance analysis versus clinical criteria for guiding ultrafiltration in hemodialysis patients: effects on blood pressure, hydration status, and arterial stiffness.

BACKGROUND: Chronic fluid overload is common in maintenance hemodialysis (HD) patients and is associated with severe cardiovascular complications, such as arterial hypertension, left ventricular hypertrophy, congestive heart failure, and arrhythmia. Therefore, a crucial target of HD is to achieve the so-called dry weight; however, the best way to assess fluid status and dry weight is still unclear. Dry weight is currently determined in most dialysis units on a clinical basis, and it is commonly defined as the lowest body weight a patient can tolerate without developing intra-dialytic or inter-dialytic hypotension or other symptoms of dehydration. One of the most promising methods that have emerged in recent years is bioelectrical impedance analysis (BIA), which estimates body composition, including hydration status, by measuring the body's resistance and reactance to electrical current. Our objective was to study the effect BIA-guided versus clinical-guided ultrafiltration on various cardiovascular disease risk factors and markers in HD patients. MATERIALS AND METHODS: We included 135 HD patients from a single center in a prospective study, aiming to compare the long-term (12 months) effect of BIA-based versus clinical-based assessment of dry weight on blood pressure (BP), pulse wave velocity (PWV), and serum N-terminal fragment of B-type natriuretic peptide (NT-proBNP). The body composition was measured using the portable whole-body multifrequency BIA device, Body Composition Monitor-BCM(®) (Fresenius Medical Care, Bad Homburg, Germany). RESULTS: In the "clinical" group there were no changes in BP, body mass index (BMI), and body fluids. The PWV increased from 7.9 ± 2.5 to 9.2 ± 3.6 m/s (P = 0.002), whereas serum NT-proBNP decreased from 5,238 to 3,883 pg/ml (P = 0.05). In the "BIA" group, BMI and body volumes also did not change; however, there was a significant decrease in both systolic BP, from 144.6 ± 14.7 to 135.3 ± 17.8 mmHg (P < 0.001), and diastolic BP, from 79.5 ± 9.7 to 73.2 ± 11.1 mmHg (P < 0.001). In this group, PWV also decreased from 8.2 ± 2.3 to 6.9 ± 2.3 m/s (P = 0.001) and NT-proBNP decreased from 7,552 to 4,561 pg/ml (P = 0.001). CONCLUSION: BIA is not inferior and possibly even better than clinical criteria for assessing dry weight and guiding ultrafiltration in HD patients.

Nutritional status evaluation and survival in haemodialysis patients in one centre from Romania.

BACKGROUND: Protein-energy wasting is a common complication and an important predictive factor for mortality in chronic dialysis patients. Therefore, nutritional status needs to be regularly assessed in these patients, by using several methods, and, if malnutrition is present, its possible causes should be thoroughly searched for and properly treated. MATERIAL AND METHODS: In 149 prevalent haemodialysis patients (82 men, mean age 53.9 +/- 13.7 years), we evaluated the nutritional status by anthropometrics [post-dialysis height (H), body weight (BW), body mass index (BMI), mid-arm circumference (MAC), tricipital skin-fold thickness (TST), mid-arm muscle circumference (MAMC), corrected mid-arm muscle area (cMAMA) and three-category subjective global assessment score (SGA)], biochemical tests [protein equivalent of nitrogen appearance (nPNA), and pre-dialysis serum albumin, creatinine, total cholesterol, bicarbonate and haemoglobin (Hb) levels] and bioelectrical impedance analysis (BIA) to estimate body composition [percent body fat (%BF), fat-free mass (%FFM), body cell mass (%BCM), extracellular mass (%ECM) and the phase angle (PhA)]. RESULTS: Age was found to be positively correlated with BMI (P = 0.001), and inversely correlated with %BCM (P = 0.013). Patients with A-category SGA were significantly younger (50.1 versus 63.7 years) than those with B-category SGA. Patients with diabetes had lower %BCM (32.9 versus 35.9%; P = 0.035) and PhA (5.5 versus 6.9 degrees ; P = 0.0007) than those without diabetes. The presence of heart failure was associated with significantly reduced nPNA (1.17 versus 1.34 g/kg day; P = 0.014), MAMC (22.0 versus 23.6 cm(2); P = 0.041), %BCM (33.0 versus 36.1; P = 0.021), PhA (5.8 versus 7.0 degrees ; P = 0.031), serum albumin (39.7 versus 42.4 g/l; P = 0.013) and serum creatinine (8.1 versus 9.4 mg/dl; P = 0.010), and with a higher percent of B-category SGA (47.8% versus 22.6%; P = 0.019). Eleven deaths (7.4%) occurred during the follow-up period. Among general factors, age >or= 55, the presence of diabetes, and dialysis vintage <2 years were associated with significantly reduced survival. Among nutritional factors, B-category SGA, nPNA <1.2 g/kg day, %BF <15% and PhA <6 degrees significantly predicted mortality in both Kaplan-Meier and Cox analyses. The most important risk factor appeared to be nPNA; for every 0.1 g/kg day increase in nPNA, death risk decreased by 15%. CONCLUSIONS: In our haemodialysis patients, advancing age, diabetes and heart failure were associated with worse nutritional status, as estimated by anthropometry, biochemical markers and BIA. Age >or=55 years, the presence of diabetes, nPNA <1.2 g/kg day, lower SGA score, %BF <15% and PhA <6 degrees were associated with significantly increased death risk.

The impact of acute kidney injury on short-term survival in an Eastern European population with stroke.

BACKGROUND: Stroke is one of the leading causes of death and of serious disability with significant impact on patients' long-term survival. The short-term evolution following stroke can associate acute kidney injury (AKI) as a possible complication, frequently overlooked and underestimated in clinical trials. We aimed to describe in an East European cohort (i) the incidence of AKI and its risk factors; (ii) the 30-day mortality and its risk factors and (iii) the relationship between mortality, pre-existent renal function and subsequent AKI. METHODS: A total of 1090 consecutive cases hospitalized-during a 12-month period-with a CT-confirmed diagnosis of stroke, from a distinct administrative region were included. Demographic details, comorbidities, laboratory and outcome data were retrieved from the electronic hospital database. All patients included in the study were followed for 30 days or until death. RESULTS: The mean age of this population was 66.1 +/- 11.5 years, 49.3% were males, mean glomerular filtration rate (GFR) 68.9 +/- 22.6 ml/min/1.73 m(2). The 30-day mortality rate was 17.2%. One hundred and fifty-eight patients presented with haemorrhagic stroke and 932 patients had ischaemic stroke. Stroke mortality was-14% for ischaemic stroke and almost twice as high for haemorrhagic stroke-36.3%. One hundred fifty-eight (14.5%) patients were classified as developing AKI. The AKI patients were older, had a higher baseline serum creatinine, lower GFR, higher serum glucose, higher prevalence of chronic heart failure and ischaemic heart disease, were more likely to have suffered a haemorrhagic stroke, and had a significantly higher 30-day mortality rate (43.1 vs 12.8%) (P < 0.05 for all). Independent predictors for AKI development in the logistic regression analysis were age, GFR, presence of comorbidities (ischaemic heart disease and chronic heart failure) and type of stroke (Cox and Snell R(2) 0.244; Nagelkerke R(2) 0.431; P < 0.05). In our study, we demonstrated that the occurrence of AKI is not a rare finding in stroke patients. This is the first study to report the incidence of AKI in a distinct geographic population base, in patients with stroke. Baseline renal function emerged as both a significant independent marker for short-term survival after an acute stroke (even after adjustment for baseline comorbidities) and as a risk factor for subsequent AKI.

Intradialytic changes in reflective properties of the arterial system during a single hemodialysis session.

Increased aortic stiffness-measured as aortic augmentation index (AIx), a global stiffness marker-has emerged as a powerful predictor of survival in hemodialysis (HD). A single HD session is known to produce considerable improvement in aortic stiffness. We set out, for the first time, to examine the relative contributions to the post-HD drastic improvement in aortic stiffness of ultrafiltration rate and volume, or blood pressure (BP) changes. Aortic AIx (difference between the first and the second systolic peak of the aortic pressure waveform divided by pulse wave height) was determined hourly and recorded by applanation tonometry using a SphygmoCor device in 20 chronic HD patients (9 males, age 55.1 years). The other parameters recorded were: weight pre- and post-HD, ultrafiltration volume (UFV), hemoglobin, albumin, creatinine, urea reduction rate (URR), calcium and PTH, and BP. The dialysis significantly decreased AIx from 24.2+/-11.27% to 15.57+/-12.58% (p<0.05). In a univariate analysis, the intradialytic decrease in AIx (AIx 0-4) did not correlate with UFV, URR or with any of the biochemical markers. Significant correlations for AIx 0-4 were age (p=0.018), systolic blood pressure (SBP) at the beginning of HD (p=0.049), the intradialytic decrease in the SBP (p=0.001), and in pulse pressure (PP) (p=0.009). Multivariate stepwise regression showed that the decrease in SBP, PP, and intradialytic percentage reduction in weight explained 64.9% of the total variation in AIx 0-4. The decrease in SBP was the most important factor influencing the AIx variation (b=1.54, p=0.007). The most significant reduction in AIx was from the beginning of HD to the third hour (p=0.039), and correlated with the reduction in SBP (p=0.006) and PP (p=0.025) between the same moments. A single HD session produces a drastic improvement in aortic stiffness. The effect is not explained by the UFV depletion but is highly correlated with the decrease in SBP and PP. Further work is now needed to explore a potential role for endothelin and nitric oxide metabolism.