B. Fekete

Pulse Wave Velocity in End-Stage Renal Disease: Influence of Age and Body Dimensions

Arterial stiffness increases with age. This process is accelerated by end-stage renal disease (ESRD). Pulse wave velocity (PWV) increases with arterial stiffness. In this study, PWV of 133 healthy individuals (6–23 y of age) and 11 patients on dialysis was measured to establish the normal values of PWV and to compare them with those in ESRD. Age-matched (A-C) and height- and weight-matched (H/W-C) control groups were used. Thereafter, PWV was indexed to height and the data were reevaluated. The role of the risk factors including serum calcium, phosphate, parathyroid hormone (PTH), and the time on dialysis was analyzed using a score system. PWV correlated with age, weight, height, blood pressure, and heart rate. ESRD patients were smaller than A-C and older than H/W-C. PWV of patients with ESRD did not differ from A-C; however, it was elevated in comparison to H/W-C. In both healthy and ESRD patients, the PWV/height ratio was independent of age. PWV/height was increased in ESRD. There was a correlation between PWV/height and the risk factor score. Controls matched for height and weight or PWV/height should be used in cases of growth failure. A number of risk factors responsible for increased arterial stiffness are present in ESRD.

Serum osteoprotegerin level, carotid-femoral pulse wave velocity and cardiovascular survival in haemodialysis patients

BACKGROUND Osteoprotegerin (OPG) is a marker and regulator of arterial calcification, and it is related to cardiovascular survival in haemodialysis patients. The link between OPG and aortic stiffening--a consequence of arterial calcification--has not been previously evaluated in this population, and it is not known whether OPG-related mortality risk is mediated by arterial stiffening. METHODS At baseline, OPG and aortic pulse wave velocity (PWV) were measured in 98 chronic haemodialysis patients who were followed for a median of 24 months. The relationship between OPG and PWV was assessed by multivariate linear regression. The role of PWV in mediating OPG related cardiovascular mortality was evaluated by including both OPG and PWV in the same survival model. RESULTS At baseline mean (standard deviation) PWV was 11.2 (3.3) m/s and median OPG (interquartile range) was 11.1 (7.5-15.9) pmol/L. There was a strong, positive, linear relationship between PWV and lnOPG (P = 0.009, model R(2) = 0.540) independent of covariates. During follow-up 23 patients died of cardiovascular causes. In separate univariate survival models both PWV and lnOPG were related to cardiovascular mortality [hazard ratios 1.31 (1.14-1.50) and 8.96 (3.07-26.16), respectively]. When both PWV and lnOPG were entered into the same model, only lnOPG remained significantly associated with cardiovascular mortality [hazard ratio 1.11 (0.93-1.33) and 7.18 (1.89-27.25), respectively). CONCLUSION In haemodialysis patients OPG is strongly related to PWV and OPG related cardiovascular mortality risk is, in part, mediated by increased PWV.

Pulse wave velocity in children following renal transplantation

BACKGROUND Arterial stiffness (ASt) increases with age, a process accelerated by uraemia and reversed by transplantation (Tx). Increased ASt results in an elevated pulse wave velocity (PWV). METHODS To compare the PWV of Tx patients (n = 25, age = 15.1/95% CI = 13.5-16.7/year) and healthy controls, three control groups were formed: matched for age (A), for height and weight (H/W) and for age and height (A/H), respectively. To avoid bias from the growth deficit of Tx, firstly Z-scores of PWV were calculated (PWV-Z). Second, the PWV/height (PWV/h) ratio was assessed. Pre-Tx serum Ca, P, PTH and the cumulative dose of calcitriol (cCTL) were also analysed. Finally, Tx patients were compared to ESRD patients (n = 11). PWV was measured by applanation tonometry. RESULTS Tx were smaller than A and older than H/W. The PWV of Tx differed only from H/W and A/H. PWV-Z and PWV/h of Tx were increased compared to all control groups. They correlated with the CaxP and cCTL before Tx and were independent of age. Patients with creatinine clearance >90 ml/min/1.73 m(2) or <1 year on dialysis had lower PWV-Z and PWV/h than ESRD. CONCLUSION Controls that matched for both age and height should be used to assess PWV in children with growth failure. PWV-Z is a universal age-independent parameter of PWV in cases of growth retardation; PWV/h is a simple alternative of PWV-Z. CaxP and cCTL are major determinants of ASt after Tx. PWV may be reduced after Tx suggesting that the uraemia-induced cardiovascular changes might be reversible.

Primary-care physicians' views about the use of home/self blood pressure monitoring: nationwide survey in Hungary.

Objective To obtain unbiased views of primary-care physicians about home blood pressure monitoring (HBPM). Methods A mail survey was conducted in a random sample (n = 700) of all Hungarian primary-care physicians (n = 5112). Items in the questionnaire related to the extent and indications for use of HBPM, to the significance attributed to its results, to the methods of its use, and to concerns physicians had with HBPM. Results Of the 700 questionnaires, 405 (58%) could be analysed. HBPM was popular among the respondents: 60% of them had more then 50 patients on HBPM, 90% of them were recommending its use either ‘often’ or ‘almost all the time’, and 75% of them considered the results of HBPM of either ‘considerable’ or of ‘extreme importance’. The most frequent indications for use were white-coat hypertension (97%), assessing 24-h drug effects (87%), improving compliance (82%), suspicion of hypotension (63%), and resistant hypertension (61%). Physicians actively recommended devices with an upper-arm cuff (83%), equipped with a built in memory (63%). Most respondents (67%) had someone in their offices to teach the patient the correct measurement technique. Surprisingly, 65% of the physicians only reviewed the data to obtain a ‘general picture’ and did not analyse the data. Most of the respondents (78%) encouraged their patients to call their offices, and 90% of them did receive a call. Main concerns with HBPM were the use of non-validated devices (75%), and patient preoccupation with blood pressure (55%). Areas for suggested improvements were the need for patient training facilities (48%), established measurement protocols (44%) and better methods of displaying readings (30%). Conclusions We found an unexpected popularity in the use of HBPM among primary-care physicians. In order to fully exploit the benefits of HBPM, the concerns raised (validated devices, patient preoccupation) and areas to be improved upon (patient training, better methods of displaying results) will have to be addressed by researchers, societies and the industry.

The Method of Distance Measurement and Torso Length Influences the Relationship of Pulse Wave Velocity to Cardiovascular Mortality

BACKGROUND The method of estimating distance traveled by the pulse wave, used in the calculation of pulse wave velocity (PWV), is not standardized. Our objective was to assess whether different methods of distance measurement influenced the association of PWV to cardiovascular mortality in hemodialysis (HD) patients. METHODS Ninety-eight chronic HD patients had their PWV measured using three methods for distance estimation; PWV1: suprasternal notch-to-femoral site minus suprasternal notch-to-carotid site, PWV2: carotid-to-femoral site, PWV3: carotid-to-femoral site minus suprasternal notch-to-carotid site. Carotid-to-femoral distance was used to approximate torso length. Patients were followed for a median of 30 months and the association of PWV and cardiovascular mortality was assessed using survival analysis before and after stratification for torso length. RESULTS The three methods resulted in significantly different PWV values. During follow-up 50 patients died, 32 of cardiovascular causes. In log-rank tests, only tertiles of PWV1 was significantly related to outcome (P values 0.017, 0.257, 0.137, for PWV1, PWV2, and PWV3, respectively). In adjusted Cox, proportional hazards regression only PWV1 was related to cardiovascular mortality. In stratified analysis, however, among patients with below median torso length all PWV values were related to outcome, whereas in patients with above median torso length none of the PWV methods resulted in significant relationship to outcome. CONCLUSIONS PWV calculated using suprasternal notch-to-femoral distance minus suprasternal notch-to-carotid distance provides the strongest relationship to cardiovascular mortality. Longer torso weakens the predictive value of PWV, possibly due to more tortuosity of the aorta hence, more error introduced when using surface tape measurements.

The effect of low-dose carvedilol, nebivolol, and metoprolol on central arterial pressure and its determinants: a randomized clinical trial.

In this prospective, open‐label, randomized, controlled clinical trial the effects of low‐dose carvedilol, nebivolol, and metoprolol on central arterial pressure and augmentation index (AIx) and its heart rate–corrected value (AIx@75) were assessed. The authors randomized 75 hypertensive patients (18–70 years) to carvedilol 12.5/25 mg, metoprolol 50/100 mg, or nebivolol 2.5/5 mg daily and followed them up for 3 months. Central arterial pressure and AIx were measured with applanation tonometry at baseline and at the end of follow‐up. Analyses were restricted to 60 completers. Central systolic pressure decreased equally in all 3 treatment arms. AIx remained unchanged, while AIx@75 decreased significantly by 5.4%±2.5% in the nebivolol group. According to general linear models, individual change in heart rate was a strong predictor of change in AIx in the carvedilol group (r2=0.23, P=.03) although no similar association was found in the nebivolol group (r2=0.09). The impact of β‐blockers with vasodilator effects on pressure augmentation seems to be different with nebivolol having the largest potential of decreasing AIx@75. While AIx changes associated with carvedilol treatment are strongly driven by heart rate changes, those associated with nebivolol treatment seem to be the result of other mechanisms.

Effect of sevelamer on aortic pulse wave velocity in patients on hemodialysis: A prospective observational study

Aortic stiffening and aortic calcification are risk factors for cardiovascular events in hemodialysis (HD) patients, and these 2 risk factors are interrelated. Sevelamer decreases aortic calcification but its effect on aortic stiffness has not been investigated previously. Thirteen HD patients commencing sevelamer treatment and 13 matched controls were followed for 11 months. Aortic pulse wave velocity (PWV), augmentation index (AIx), and levels of inhibitors of vascular calcification (fetuin‐A, matrix‐GLA‐protein, osteoprotegerin/RANKL) were measured at baseline and at the end of follow‐up, and the differences between the groups were compared. Determinants of the changes in PWV during follow‐up were assessed by multivariate linear regression. At baseline, PWV was 9.93 (2.10) m/s in sevelamer‐treated patients and 9.20 (2.84) m/s in control patients (p=0.464). By the end of follow‐up, PWV decreased by 0.83 (2.3) m/s in sevelamer‐treated patients while it increased by 0.93 (1.88) m/s in controls (p=0.042). The direction of changes in AIx were similar, but not statistically significant. There were no significant differences in the levels of inhibitors of calcification either at baseline or during follow‐up. In multivariate linear regression sevelamer treatment, diabetes, heart rate, and C‐reactive protein were related to the change in PWV. These data suggest that sevelamer treatment is associated with an improvement in aortic stiffness in HD patients, but it does not seem to affect serum levels of inhibitors of vascular calcification.

Arterial Stiffness in Hemodialysis: Which Parameter to Measure to Predict Cardiovascular Mortality?

In previous studies, different parameters of arterial stiffness were related to cardiovascular mortality in hemodialysis patients, but their relative prognostic value has not previously been evaluated in 1 cohort. Carotid-femoral pulse wave velocity (PWV), the carotid augmentation index, carotid pulse pressure (CPP) and carotid-brachial pulse pressure amplification (AMP) were measured in 98 patients before and after hemodialysis. Patients were followed for a median of 29 months (1–34) and the association of these parameters with cardiovascular mortality were assessed using log-rank tests and Cox proportional hazards regressions. During follow-up, 25 patients died of cardiovascular causes. Increasing pre- and postdialysis PWV tertiles and decreasing predialysis AMP tertiles were significantly related to cardiovascular mortality (p = 0.012 and 0.011 for PWV, respectively; < 0.001 for AMP). Neither the carotid augmentation index nor carotid pulse pressure were related to cardiovascular mortality. The adjusted hazard ratios for 1 m/s higher pre- and postdialysis PWV were 1.24 (1.07–1.44) and 1.17 (1.06–1.28), respectively. The hazard ratio for 10% lower predialysis AMP was 1.41 (1.03–1.92). When included in the same model, both predialysis PWV and AMP remained significantly associated with cardiovascular mortality. Among different stiffness parameters, PWV is consistently related to cardiovascular mortality, irrespective of the timing of measurement. Predialysis AMP seems to provide additional prognostic information.