Hemodialysis patients with intradialytic rise in blood pressure display higher baseline aortic stiffness and negligible drop in augmentation index with dialysis.

BACKGROUND: In hemodialysis patients, the intradialytic rise in blood pressure (BP) is associated with increased mortality risk. However, the mechanisms of this adverse effect are not yet elucidated. This study examined whether intradialytic rise in BP is associated with increased arterial stiffness and wave reflections, which are powerful cardiovascular risk predictors in hemodialysis. METHODS: The pattern of intradialytic hemodynamic response was evaluated in 70 prevalent hemodialysis patients, by measuring seated brachial BP before and after the mid-week dialysis session. All patients had pre- and post-dialysis determination of aortic pulse wave velocity (PWV) and heart rate-adjusted augmentation index [AIx(75)], as measures of arterial stiffness and wave reflections, with the Sphygmocor device. RESULTS: Intradialytic rise in brachial systolic BP (SBP) was evident in 17 patients, whereas intradialytic change in SBP (ΔSBP) of -10 to 0 mmHg was observed in 23 and ΔSBP greater than -10 mmHg in 30 patients. Participants with intradialytic SBP rise had significantly higher pre-dialysis aortic PWV (10.4 ± 1.6 vs 8.3 ± 1.9 vs 9.4 ± 2.4 m/s, P < 0.01) and AIx(75) (28.1 ± 7.3 vs 21.7 ± 8.6 vs 25.8 ± 8.2%, P < 0.05) than those experiencing intradialytic ΔSBP of -10 to 0 and greater than -10 mmHg, respectively. Patients with rise in SBP during dialysis exhibited also lower intradialytic reduction in AIx(75) (-1.5 ± 4.9 vs -5.4 ± 5.9 vs -6.7 ± 5.3%, P < 0.001). CONCLUSIONS: This study shows that aortic stiffness and wave reflections are higher and not affected by dialysis procedure in patients with intradialytic SBP rise, suggesting that accelerated arteriosclerosis may be one possible explanation for the heightened cardiovascular risk associated with intradialytic hypertension.

Ambulatory recording of wave reflections and arterial stiffness during intra- and interdialytic periods in patients treated with dialysis.

BACKGROUND AND OBJECTIVES: Wave reflections and arterial stiffness are independent cardiovascular risk factors in ESRD. Previous studies in this population included only static recordings before and after dialysis. This study investigated the variation of these indices during intra- and interdialytic intervals and examined demographic, clinical, and hemodynamic variables related to arterial function in patients undergoing hemodialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Between February 2013 and May 2014, a total of 153 patients receiving maintenance hemodialysis in five dialysis centers of northern Greece underwent ambulatory BP monitoring with the newly introduced Mobil-O-Graph device (IEM, Stolberg, Germany) over a midweek dialysis session and the subsequent interdialytic period. Mobil-O-Graph is an oscillometric device that records brachial BP and pulse waves and estimates, via generalized transfer function, aortic BP, augmentation index (AIx) as a measure of wave reflections, and pulse wave velocity (PWV) as an index of arterial stiffness. RESULTS: AIx was lower during dialysis than in the interdialytic period of dialysis-on day (Day 1) (mean±SD, 24.7%±9.7% versus 26.8%±9.4%; P<0.001). In contrast, PWV remained unchanged between these intervals (9.31±2.2 versus 9.29±2.3 m/sec; P=0.60). Both AIx and PWV increased during dialysis-off day (Day 2) versus the out-of-dialysis period of Day 1 (28.8%±9.8% versus 26.8%±9.4% [P<0.001] and 9.39±2.3 versus 9.29±2.3 m/sec [P<0.001]). Older age (odds ratio [OR], 1.09; 95% confidence interval [95% CI], 1.02 to 1.15), female sex (OR, 7.56; 95% CI, 1.64 to 34.81), diabetic status (OR, 8.84; 95% CI, 1.76 to 17.48), and higher mean BP (OR, 1.17; 95% CI, 1.09 to 1.27) were associated with higher odds of high AIx; higher heart rate was associated with lower odds (OR, 0.71; 95% CI, 0.63 to 0.80) of high AIx. Older age (OR, 2.04; 95% CI, 1.61 to 2.58) and higher mean BP (OR, 1.15; 95% CI, 1.05 to 1.27) were independent correlates of high PWV. CONCLUSIONS: This study showed a gradual interdialytic increase in AIx, whereas PWV was only slightly elevated during Day 2. Future studies are needed to elucidate the value of these ambulatory measures for cardiovascular risk prediction in ESRD.

Hemodiafiltration does not have additional benefits over hemodialysis on arterial stiffness, wave reflections and central aortic pressures.

BACKGROUND/AIMS: The hypothesis that dialytic modality affects arterial stiffness was never investigated. This study includes comparative evaluation of hemodiafiltration versus hemodialysis on arterial function during first and second weekly dialysis sessions. METHODS: 24 patients receiving hemodiafiltration and another 24 age- and sex-matched controls receiving hemodialysis were included. Patients were evaluated before and after first and second weekly dialysis sessions. Applanation tonometry of peripheral arteries was applied to determine aortic and brachial pulse wave velocity and heart rate-adjusted augmentation index (AIx(75)). RESULTS: Hemodiafiltration and hemodialysis reduced AIx(75), but not aortic and brachial pulse wave velocity. Intradialytic reductions in AIx(75) did not differ between hemodiafiltration and hemodialysis in first and mid-week dialysis. In multivariate linear regression, predictors of intradialytic reduction in AIx(75) were changes in body weight and central aortic systolic blood pressure, but not dialytic modality. CONCLUSION: This study showed that hemodiafiltration has similar effects with hemodialysis on wave reflections and stiffness.

Elevated leptin fragments in renal failure correlate with BMI and haematopoiesis and are normalized by haemodialysis.

OBJECTIVE: Leptin is an adipocyte hormone important in appetite, energy homeostasis, neuroendocrine and haematopoietic function. Patients with renal failure often have elevated total and free leptin levels. Biologically active leptin fragments (leptin(22-56) and leptin(57-92)) have been identified, but whether these fragments are affected by renal failure and/or haemodialysis (HD) is not known. RESEARCH METHODS: Leptin, leptin(22-56) and leptin(57-92) levels were measured in 28 HD patients [14 men, 14 women, age 45.5 +/- 16.4 years, body mass index (BMI) 23.8 +/- 3.6 kg/m2] and 25 healthy controls with similar age and BMI. In 18 HD patients, leptin and fragment levels were measured before and after 2 consecutive dialysis treatments and on the intermediate, dialysis-free day. RESULTS: Baseline leptin levels were higher in HD patients vs. controls (69.3 +/- 62.2 ng/ml vs. 30.4 +/- 32.7, P < 0.02) as were leptin(22-56) (7.14 +/- 7.04 ng/ml vs. 1.86 +/- 1.84, P < 0.02) and leptin(57-92) (5.94 +/- 6.08 ng/ml vs. 1.58 +/- 1.98, P < 0.02). Baseline leptin and fragment levels correlated significantly and independently with BMI in HD patients (r = 0.70, r = 0.59, r = 0.72, respectively, P < 0.001). After each HD session, leptin levels were reduced to levels not different from controls, but increased on the intermediate, dialysis-free day. Similar to and independently from total leptin, both leptin fragments were reduced after the first HD session to levels not different from controls. The reduction in leptin levels was higher with synthetic vs. cellulosic membrane types (37.7 +/- 23.5%vs. 18.1 +/- 21.8%, P < 0.03). Leptin correlated weakly with the erythropoietin to haematocrit ratio (T = -0.20, P = 0.14), while leptin(22-56) had a significant negative correlation with this index (T = -0.42, P < 0.01), suggesting that this fragment may favour haematopoiesis. DISCUSSION: Leptin fragments are detected in human serum, and both leptin and leptin fragments correlate with BMI, are significantly elevated in HD patients compared to controls, and are significantly decreased by haemodialysis. The elevated leptin fragments may have important physiological significance for the anorexia, hypogonadism, and anaemia commonly seen in HD patients, but this remains to be conclusively shown by interventional trials.