Athanasios Bikos

Evaluation of a novel brachial cuff-based oscillometric method for estimating central systolic pressure in hemodialysis patients.

Background/Aims: Elevated wave reflections and arterial stiffness, as well as ambulatory blood pressure (BP) are independent predictors of cardiovascular risk in end-stage-renal-disease. This study is the first to evaluate in hemodialysis patients the validity of a new ambulatory oscillometric device (Mobil-O-Graph, IEM, Germany), which estimates aortic BP, augmentation index (AIx) and pulse wave velocity (PWV). Methods: Aortic SBP (aSBP), heart rate-adjusted AIx (AIx(75)) and PWV measured with Mobil-O-Graph were compared with the values from the most widely used tonometric device (Sphygmocor, ArtCor, Australia) in 73 hemodialysis patients. Measurements were made in a randomized order after 10 min of rest in the supine position at least 30 min before a dialysis session. Brachial BP (mercury sphygmomanometer) was used for the calibration of Sphygmocors waveform. Results: Sphygmocor-derived aSBP and AIx(75) did not differ from the relevant Mobil-O-Graph measurements (aSBP: 136.3 ± 19.6 vs. 133.5 ± 19.3 mm Hg, p = 0.068; AIx(75): 28.4 ± 9.3 vs. 30.0 ± 11.8%, p = 0.229). The small difference in aSBP is perhaps explained by a relevant difference in brachial SBP used for calibration (146.9 ± 20.4 vs. 145.2 ± 19.9 mm Hg, p = 0.341). Sphygmocor PWV was higher than Mobil-O-Graph PWV (10.3 ± 3.4 vs. 9.5 ± 2.1 m/s, p < 0.01). All 3 parameters estimated by Mobil-O-Graph showed highly significant (p < 0.001) correlations with the relevant measurements of Sphygmocor (aSBP, r = 0.770; AIx(75), r = 0.400; PWV, r = 0.739). The Bland-Altman Plots for aSBP and AIx(75) showed acceptable agreement between the two devices and no evidence of systemic bias for PWV. Conclusion: As in other populations, acceptable agreement between Mobil-O-Graph and Sphygmocor was evident for aSBP and AIx(75) in hemodialysis patients; PWV was slightly underestimated by Mobil-O-Graph.

Blood pressure variability is increasing from the first to the second day of the interdialytic interval in hemodialysis patients

Objectives: Patients with end-stage renal-disease under hemodialysis have increased cardiovascular risk and experience severe blood pressure (BP) fluctuations during the dialysis session and the subsequent interdialytic period. BP variability (BPV) may be an additional risk factor for cardiovascular events and preliminary data suggest increased BPV with advancing stages of chronic kidney disease. This is the first study to examine BPV during the whole intradialytic and interdialytic period in hemodialysis patients with ambulatory BP monitoring. Methods: A total of 160 patients receiving maintenance hemodialysis had 48-h ambulatory BP monitoring with the Mobil-O-Graph device during a regular dialysis session and the subsequent interdialytic interval. Brachial and aortic BPV were calculated with validated formulas and were compared between Days 1 and 2 of the interdialytic period (44-h), Days 1 and 2 of the total 48-h interval (including the dialysis session), and between the two respective daytime periods and night-time periods. Results: All brachial SBPV indices [SD: 14.75 ± 4.38 vs. 15.91 ± 4.41, P = 0.001; weighted SD: 13.80 ± 4.00 vs. 14.89 ± 3.90, P < 0.001; coefficient of variation (CV): 11.34 ± 2.91 vs. 11.93 ± 2.94, P = 0.011; average real variability (ARV): 11.38 ± 3.44 vs. 12.32 ± 3.65, P < 0.001)] were increasing from Days 1 to 2 of the 44-h interdialytic period. Similarly, all indexes of DBPV were significantly increased in Day 2, except for CV. Aortic SBPV and DBPV indices displayed a similar pattern. Furthermore, all studied brachial SBPV and DBPV indexes were also lower during daytimes 1 than 2 (systolic ARV 11.56 ± 3.98 vs. 12.44 ± 4.03, P = 0.002); systolic ARV was lower in night-time 1 compared with night-time 2 (11.20 ± 5.09 vs. 12.18 ± 4.66, P = 0.045). In multivariate regression analysis prehemodialysis SBP, age and diabetes were independently associated with increased SBP ARV. Conclusion: BPV is increased in interdialytic Day 2 compared with Day 1 in hemodialysis patients; this could be another mechanism involved in the complex cardiovascular pathophysiology and increased cardiovascular mortality of these individuals.

Prevalence and control of hypertension by 48-h ambulatory blood pressure monitoring in haemodialysis patients: a study by the European Cardiovascular and Renal Medicine (EURECA-m) working group of the ERA-EDTA

Background Population-specific consensus documents recommend that the diagnosis of hypertension in haemodialysis patients be based on 48-h ambulatory blood pressure (ABP) monitoring. However, until now there is just one study in the USA on the prevalence of hypertension in haemodialysis patients by 44-h recordings. Since there is a knowledge gap on the problem in European countries, we reassessed the problem in the European Cardiovascular and Renal Medicine working group Registry of the European Renal Association-European Dialysis and Transplant Association. Methods A total of 396 haemodialysis patients underwent 48-h ABP monitoring during a regular haemodialysis session and the subsequent interdialytic interval. Hypertension was defined as (i) pre-haemodialysis blood pressure (BP) ≥140/90 mmHg or use of antihypertensive agents and (ii) ABP ≥130/80 mmHg or use of antihypertensive agents. Results The prevalence of hypertension by 48-h ABP monitoring was very high (84.3%) and close to that by pre-haemodialysis BP (89.4%) but the agreement of the two techniques was not of the same magnitude (κ statistics = 0.648; P <0.001). In all, 290 participants were receiving antihypertensive treatment. In all, 9.1% of haemodialysis patients were categorized as normotensives, 12.6% had controlled hypertension confirmed by the two BP techniques, while 46.0% had uncontrolled hypertension with both techniques. The prevalence of white coat hypertension was 18.2% and that of masked hypertension 14.1%. Of note, hypertension was confined only to night-time in 22.2% of patients while just 1% of patients had only daytime hypertension. Pre-dialysis BP ≥140/90 mmHg had 76% sensitivity and 54% specificity for the diagnosis of BP ≥130/80 mmHg by 48-h ABP monitoring. Conclusions The prevalence of hypertension in haemodialysis patients assessed by 48-h ABP monitoring is very high. Pre-haemodialysis BP poorly reflects the 48 h-ABP burden. About a third of the haemodialysis population has white coat or masked hypertension. These findings add weight to consensus documents supporting the use of ABP monitoring for proper hypertension diagnosis and treatment in this population.

PREVALENCE AND CONTROL OF HYPERTENSION WITH THE USE OF AMBULATORY BLOOD PRESSURE RECORDING IN HEMODIALYSIS PATIENTS

Objective: To date, there is no commonly accepted definition for hypertension in patients with chronic kidney disease undergoing hemodialysis. A recent expert consensus suggests hypertension in dialysis to be defined based on ambulatory blood pressure monitoring (ABPM). The aim of this study is to evaluate the prevalence and control of hypertension using ABPM in a large hemodialysis population according to the latest definitions. Design and method: A total of 160 hemodialysis patients underwent 48-hour ABPM, during a regular hemodialysis session and the subsequent interdialytic interval. Hypertension was defined as (i) pre-hemodialysis BP >  = 140/90 mmHg or use of antihypertensive agents (ii) ambulatory BP >  = 130/80 mmHg (over 44-hours or over the second 24hour period) or use of antihypertensive agents. Phenotypes of hypertension control were defined as: 1) concordant control (pre-hemodialysis BP < 140/90 mmHg and ambulatory-BP < 130/80 mmHg), 2) concordant lack of control (pre-hemodialysis BP >  = 140/90 mmHg and ambulatory-BP >  = 130/80 mmHg), 3) “white coat” phenomenon (pre-hemodialysis BP >  = 140/90 mmHg and ambulatory-BP < 130/80 mmHg) and 4) masked hypertension (pre-hemodialysis BP < 140/90 mmHg and ambulatory-BP >  = 130/80 mmHg). Results: Based on pre-hemodialysis BP levels, the prevalence of hypertension was 91.3% Based on the ABPM covering the total 44-hour or the 2nd 24-hour interdialytic period, the prevalence was 88.8%. The proportion of hypertensive patients receiving treatment was 124 (84,9%). With the use of pre-hemodialysis BP and ABPM during 44-hours, 12 (10.1%) of hypertensive patients had concordant BP control, 87 (58.8%) of patients had lack of control, 29 (19.6%) had a white-coat phenomenon, and 17 (11.5) masked hypertension, respectively. In multivariate logistic regression analysis, only use of antihypertensive agents was independently associated with increased odds for lack of control (reverse causation). Conclusions: Hypertension prevalence in hemodialysis patients is overwhelmingly high. The rates of control rates are different when calculated from office and ambulatory BP recordings. In the population studied, almost one out of three patients had white-coat or masked hypertension.

NEBIVOLOL AND IRBESARTAN REDUCE POST-HEMODIALYSIS AND AMBULATORY BP IN PATIENTS WITH INTRADIALYTIC HYPERTENSION: A RANDOMIZED CROSS-OVER STUDY

Objective: Blood pressure (BP) increase during or immediately after hemodialysis is an abnormal hemodynamic response to ultrafiltration and occurs in 5–20% of patients. Intradialytic hypertension is associated with adverse clinical outcomes and is often poorly diagnosed and controlled. This study aimed to evaluate the effects of nebivolol and irbesartan in 24hour ambulatory BP in hemodialysis patients with intradialytic hypertension. Design and method: This is a randomized cross-over study in 38 hemodialysis patients (age: 60.4 ± 11.1 years, male: 65.8%) with intradialytic hypertension, defined as mean intradialytic rise >  = 10 mmHg in systolic BP (SBP) over 6 consecutive hemodialysis sessions. After baseline evaluation, patients were randomly assigned to nebivolol 5 mg and subsequently irbesartan 150 mg, or vice versa. Half of the patients received a single drug-dose 1 hour before hemodialysis (n = 19) or for a whole week, before evaluation (n = 19). A two-week wash-out period took place before the initiation of the second drug. All subjects underwent 24hour ambulatory BP monitoring starting before a midweek session. Results: In total, 20 (52.6%) patients received nebivolol first and 18 (47.4%) received irbesartan first. Patients receiving a single dose of either nebivolol or irbesartan had lower post-dialysis SBP and diastolic BP (DBP) [Baseline: 161.6 ± 16.3/95.4 ± 12.3; Nebivolol: 146.1 ± 20.4 (p = 0.003), 84.5 ± 11.8 (p < 0.001); Irbesartan: 144.7 ± 29.9 (p = 0.003), 86.8 ± 18.0 (p = 0.047) mmHg; respectively], non-significantly lower 24-hour SBP and lower DBP [Baseline: 147.8 ± 16.0/87.7 ± 11.9; Nebivolol: 144.0 ± 19.5 (p = 0.070), 83.3 ± 11.7 (p = 0.015); Irbesartan: 143.1 ± 21.7 (p = 0.171), 84.7 ± 12.8 (p = 0.095) mmHg]. Patients on weekly administration of either nebivolol or irbesartan had significantly lower post-dialysis SBP and DBP (Baseline: 167.1 ± 13.6/99.8 ± 10.6 Nebivolol: 145.2 ± 16.6 (p < 0.001), 91.0 ± 11.8 (p = 0.003); Irbesartan: 147.1 ± 23.8 (p = 0.002), 87.6 ± 12.5 (p = 0.001) mmHg), significantly lower 24-hour SBP and DBP (Baseline: 148.2 ± 12.5/91.7 ± 9.7 Nebivolol: 139.2 ± 10.4 (p < 0.001), 85.2 ± 7.7 (p = 0.001); Irbesartan: 142.9 ± 15.7 (p = 0.188), 85.5 ± 9.9 (p = 0.015) mmHg; accordingly) and significantly lower daytime and nighttime ambulatory SBP and DBP. No significant differences in BP reduction between nebivolol and irbesartan were observed. Conclusions: Both nebivolol and irbesartan reduce post-dialysis and 24-hour BP in patients with intradialytic hypertension. Weekly administration had greater effect and nebivolol seemed numerically slightly more potent than irbesartan; permanent administration of these agents may be more effective than pre-dialysis dosing.

A Comparative Study of Short-Term Blood Pressure Variability in Hemodialysis Patients with and without Intradialytic Hypertension

Background: Short-term blood pressure (BP) variability (BPV) is associated with increased cardiovascular risk in hemodialysis. Patients with intradialytic hypertension have high risk of adverse outcomes. Whether BPV is increased in these patients is not clear. The purpose of this study was to compare short-term BPV in patients with and without intradialytic hypertension. Methods: Forty-one patients with and 82 patients without intradialytic hypertension (intradialytic SBP rise ≥10 mm Hg to > 150 mm Hg) matched in a 1: 2 ratio for age, sex, and hemodialysis vintage were included. All subjects underwent 48-h ambulatory BP monitoring during a regular hemodialysis and the subsequent interdialytic interval. Brachial and aortic BPV were calculated with validated formulas and compared between the 2 groups during the 48-h and the 44-h periods and during the 2 daytime and nighttime periods respectively. Results: During 48-h or 44-h periods and daytime or nighttime, brachial SBP/DBP and aortic SBP/DBP were significantly higher in cases than in controls. All brachial SBP/DBP BPV indexes [SD, weighted SD (wSD), coefficient-of-variation (CV) and average-real-variability (ARV)] were not significantly different between groups during the 48- or 44-h periods (48-h: SBP-ARV 11.59 ± 3.05 vs. 11.70 ± 2.68, p = 0.844, DBP-ARV: 8.60 ± 1.90 vs. 8.90 ± 1.63, p = 0.357). Analysis stratified by day or night between days 1 and 2 revealed, in general, similar results. No significant differences in dipping pattern were observed between groups. Analysis of aortic BPV had similar findings. Conclusions: BPV is similar between those with and without intradialytic hypertension. However, those with intradialytic hypertension have a sustained increase in systolic and diastolic BP during the entire interdialytic interval.