Weak within-individual association of blood pressure and pulse wave velocity in hemodialysis is related to adverse outcomes

Dialysate Sodium Levels, Ambulatory Aortic Blood Pressure, and Arterial Stiffness in Hemodialysis Patients

BACKGROUND

Increased aortic blood pressure (BP) and arterial stiffness are associated with higher cardiovascular risk in hemodialysis. Previous works showed that lower dialysate sodium is associated with lower brachial-BP; data on aortic-BP and arterial stiffness are limited. This study aimed to investigate the effects of different dialysate sodium concentrations on 72-hour aortic-BP and arterial stiffness parameters in hemodialysis patients.

METHODS

This analysis is part of a prospective, non-randomized interventional study. Twenty-five hemodialysis patients underwent a set of 3 periods of different dialysate sodium concentrations; 6 sessions with dialysate sodium of 137 mEq/l, followed consecutively by 6 sessions with 139 mEq/l and, finally, 6 sessions with 141 mEq/l. At the start of the sixth hemodialysis session on each sodium concentration, 72-hour ABPM (Mobil-O-Graph) was performed to evaluate aortic-BP and arterial stiffness indices during the overall 72-hour, different 24-hour, daytime, and nighttime periods.

RESULTS

Mean 72-hour aortic systolic blood pressure (SBP)/diastolic blood pressure (DBP) were higher with increasing dialysate sodium concentrations (137 mEq/l: 114.2 ± 15.3/77.0 ± 11.8 mm Hg vs. 139 mEq/l: 115.4 ± 17.3/77.9 ± 14.0 mm Hg vs. 141 mEq/l: 120.5 ± 18.4/80.5 ± 14.7 mm Hg, P = 0.002/P = 0.057, respectively). Wave-reflection parameters (AIx, AIx(75), AP) were not significantly different between the 3 dialysate sodium concentrations. Ambulatory pulse wave velocity (PWV) was significantly higher with increasing dialysate sodium concentrations (137 mEq/l: 8.5 ± 1.7 m/s vs. 139 mEq/l: 8.6 ± 1.6 m/s vs. 141 mEq/l: 8.8 ± 1.6 m/s, P < 0.001). In generalized linear mixed models including 72-hour brachial SBP as a random covariate, the adjusted marginal means of 72-hour PWV were not significantly different between groups.

CONCLUSIONS

This study showed that higher dialysate sodium concentrations are associated with significant increases in ambulatory aortic BP and PWV. These findings further support the need for modification of dialysate sodium concentration in hemodialysis.

Association of 24-h central hemodynamics and stiffness with cardiovascular events and all-cause mortality. The VASOTENS Registry

OBJECTIVES

In hemodialysis patients, central hemodynamics, stiffness, and wave reflections assessed through ambulatory blood pressure monitoring (ABPM) showed superior prognostic value for cardiovascular (CV) events than peripheral blood pressures (BPs). No such evidence is available for lower-risk hypertensive patients.

METHODS

In 591 hypertensive patients (mean age 58 ± 14 years, 49% males), ambulatory brachial and central BP, pulse wave velocity (PWV), and augmentation index (AIx) were obtained with a validated upper arm cuff-based pulse wave analysis technology. Information on treatment for hypertension (73% of patients), dyslipidemia (27%), diabetes (8%), CV disease history (25%), was collected. Patients were censored for CV events or all-cause death over 4.2 years.

RESULTS

One hundred and four events (24 fatal) were recorded. Advanced age [hazard ratio and 95% confidence interval: 1.03 (1.01, 1.05), P  = 0.0001], female sex [1.57 (1.05, 2.33), P  = 0.027], CV disease [2.22 (1.50, 3.29), P  = 0.0001], increased 24-h central pulse pressure (PP) [1.56 (1.05, 2.31), P  = 0.027], PWV [1.59 (1.07, 2.36), P  = 0.022], or AIx [1.59 (1.08, 2.36), P  = 0.020] were significantly associated with a worse prognosis (univariate Cox regression analysis). The prognostic power of peripheral and central BPs was lower. However, PWV [1.02 (0.64, 1.63), P  = 0.924], AIx [1.06 (0.66, 1.69), P  = 0.823], and central PP [1.18 (0.76, 1.82), P  = 0.471], were not significant predictors in multivariate analyses.

CONCLUSIONS

In hypertensive patients, ambulatory central PP, PWV, and AIx are associated with an increased risk of CV morbidity and all-cause mortality. However, this association is not independent of other patient characteristics.

Aortic Stiffness: A Major Risk Factor for Multimorbidity in the Elderly

Multimorbidity, the coexistence of multiple health conditions in an individual, has emerged as one of the greatest challenges facing health services, and this crisis is partly driven by the aging population. Aging is associated with increased aortic stiffness (AoStiff), which in turn is linked with several morbidities frequently affecting and having disastrous consequences for the elderly. These include hypertension, ischemic heart disease, heart failure, atrial fibrillation, chronic kidney disease, anemia, ischemic stroke, and dementia. Two or more of these disorders (multimorbidity) often coexist in the same elderly patient and the specific multimorbidity pattern depends on several factors including sex, ethnicity, common morbidity routes, morbidity interactions, and genomics. Regular exercise, salt restriction, statins in patients at high atherosclerotic risk, and stringent blood pressure control are interventions that delay progression of AoStiff and most likely decrease multimorbidity in the elderly.

Association of peridialytic, intradialytic, scheduled interdialytic and ambulatory BP recordings with cardiovascular events in hemodialysis patients

BACKGROUND

Ambulatory-BP-monitoring (ABPM) is recommended for hypertension diagnosis and management in hemodialysis patients due to its strong association with outcomes. Intradialytic and scheduled interdialytic BP recordings show agreement with ambulatory BP. This study assesses in parallel the association of pre-dialysis, intradialytic, scheduled interdialytic and ambulatory BP recordings with cardiovascular events.

METHODS

We prospectively followed 242 hemodialysis patients with valid 48-h ABPMs for a median of 45.7 months to examine the association of pre-dialysis, intradialytic, intradialytic plus pre/post-dialysis readings, scheduled interdialytic BP, and 44-h ambulatory BP with outcomes. The primary end-point was a composite one, composed of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, resuscitation after cardiac arrest, hospitalization for heart failure, coronary revascularization procedure or peripheral revascularization procedure.

RESULTS

Cumulative freedom from the primary end-point was significantly lower with increasing 44-h SBP (group 1, < 120 mmHg, 64.2%; group 2, ≥ 120 to < 130 mmHg 60.4%, group 3, ≥ 130 to < 140 mmHg 45.3%; group 4, ≥ 140 mmHg 45.5%; logrank-p = 0.016). Similar were the results for intradialytic (logrank-p = 0.039), intradialytic plus pre/post-dialysis (logrank-p = 0.044), and scheduled interdialytic SBP (logrank-p = 0.030), but not for pre-dialysis SBP (logrank-p = 0.570). Considering group 1 as the reference group, the hazard ratios of the primary end-point showed a gradual increase with higher BP levels with all BP metrics, except pre-dialysis SBP. This pattern was confirmed in adjusted analyses. An inverse association of DBP levels with outcomes was shown with all BP metrics, which was no longer evident in adjusted analyses.

CONCLUSIONS

Averaged intradialytic and scheduled home BP measurements (but not pre-dialysis readings) display similar prognostic associations with 44-h ambulatory BP in hemodialysis patients and represent valid metrics for hypertension management in these individuals.

Ambulatory monitoring of central arterial pressure, wave reflections, and arterial stiffness in patients at cardiovascular risk

This paper reviews current 24 h ambulatory noninvasive technologies for pulse wave analysis (PWA) providing central arterial pressure, pulse wave velocity, and augmentation index and the scientific evidence supporting their use in the clinical management of patients with arterial hypertension or at risk for cardiovascular complications.The most outstanding value of these techniques lies in the fact that they are user-friendly, mostly operator independent, and enable the evaluation of vascular function during daily-life conditions, allowing to obtain repeated measurements in different out-of-office circumstances, less artificial than those of the laboratory or doctor's office.Studies performed so far suggest that 24 h PWA may represent a potentially promising tool for evaluating vascular function, structure, and damage in daily-life conditions and promoting early screening in subjects at risk. The current evidence in favor of such an approach in the clinical practice is still limited and does not recommend its routine use. In particular, at the moment, there is a shortage of long-term prognostic studies able to support the predictive value of 24 h PWA. Finally, the accuracy of the measures is strongly dependent on the type of technology and device employed with lack of interoperability among the devices that deeply affects comparability of results among studies using different technologies. It is thus mandatory in the near future to promote proper validation studies, for instance using the ARTERY protocol, and to plan well-designed long-term longitudinal studies that may prove the accuracy and high predictive value of PWA in ambulatory conditions.

Pulse Wave Velocity Assessment for Cardiovascular Risk Prognostication in ESKD: Weighting Recent Evidence

BACKGROUND

Among patients with end-stage kidney disease (ESKD), arterial stiffness is considered as a powerful predictor of cardiovascular (CV) morbidity and mortality. However, the relevance of aortic pulse wave velocity (PWV) as a prognostic biomarker for CV risk estimation is not yet fully clear.

METHODS

We performed a systematic search of Medline/PubMed database from inception through August 21, 2019 to identify observational cohort studies conducted in ESKD patients and exploring the association of PWV with CV events and mortality.

RESULTS

Whereas "historical" cohort studies showed aortic PWV to be associated with higher risk of CV and all-cause mortality, recent studies failed to reproduce the independent predictive value of aortic PWV in older ESKD patients. Studies using state-of-the-art prognostic tests showed that the addition of aortic PWV to standard clinical risk scores could only modestly improve CV risk reclassification. Studies associating improvement in PWV in response to blood pressure (BP)-lowering with improvement in survival cannot demonstrate direct cause-and-effect associations due to their observational design and absence of accurate methodology to assess the BP burden.

CONCLUSION

Despite the strong pathophysiological relevance of arterial stiffness as a mediator of CV disease in ESKD, the assessment of aortic PWV for CV risk stratification in this population appears to be of limited value. Whether aortic PWV assessment is valuable in guiding CV risk factor management and whether such a therapeutic approach is translated into improvement in clinical outcomes, is an issue of clinical relevance that warrants investigation in properly-designed randomized trials.

The association between peri-dialytic pulse wave velocity measurements and hemodialysis patient mortality

INTRODUCTION

Arterial stiffness in the general population is an independent prognostic factor for cardiovascular mortality, and can be measured noninvasively by pulse wave velocity (PWV). PWV is increased in hemodialysis (HD) patients, but the prognostic additional value remains debatable, with variable results reported. We wished to review whether increased PWV was associated with mortality in our HD patients.

METHODS

Aortic pulse wave velocity (PWVao) was measured peridialytic using an oscillograph technique (Arteriograph TensioMed, Hungary), in a cohort of HD patients in 2012.

FINDINGS

Three hundred and eighty-three HD patients, 238 (62.1%) male, median age 67.7 (54.2-78.0) years, 163 (42.6%) diabetic, Charlson comorbidity score 7 (5-9) and PWVao 8.9 (7.4-11.2) m/s were studied. Two hundred and twenty-nine deaths occurred during a median 61.1-month follow-up. PWVao was associated with all-cause mortality in unadjusted models (odds ratio [OR] for PWVao as a continuous variable 1.084, 95% confidence limits [CL] 1.046-1.124), P < 0.001, and for patients with PWVao>10 m/s (OR 1.61, CL 1.240-2.098, P < 0.001), but not after adjusting for clinical confounders (OR 1.024, CL 0.987-1.063, P = 0.208), whereas age (OR 1.049, CL 1.038-1.060, P < 0.001), and Charlson comorbidity (OR 1.131, CL1.065-1.201, P < 0.001) remained significantly associated with mortality.

DISCUSSION

Although our HD patients with an increased PWVao had greater all-cause mortality, after adjustment for age and comorbidity, the prognostic value of a single PWVao measurement was no longer an independent prognostic factor for mortality. Future studies are required to determine whether changes in PWV offer additional prognostic value for HD patients.

Significance of acPWV for Survival of Hemodialysis Patients

BACKGROUND AND OBJECTIVES

Abnormal arterial stiffness (AS) is a major complication in end-stage kidney disease (ESKD) patients treated by dialysis. Our study aimed to determine the significance of AS for survival of prevalent dialysis patients, as well as its association with cardiovascular parameters or vascular calcification promoters/inhibitors or both and AS.

MATERIALS AND METHODS

The study involved 80 adult hemodialysis patients. Besides standard laboratory analyses, we also determined promoters and inhibitors of vascular calcification (bone biomarkers): serum levels of fibroblast growth factor 23 (FGF23), soluble Klotho, intact parathormone (iPTH), 1,25-dihydroxyvitamin D3, osteoprotegerin, sclerostin, AS measured as ankle carotid pulse wave velocity (acPWV), Ankle Brachial Index (ABI), and vascular calcification (VC) score. Patients were monitored for up to 28 months. According to the median acPWV value, we divided patients into a group with acPWV ≤ 8.8 m/s, and a group with acPWV > 8.8 m/s, and the two groups were compared.

RESULTS

Values for bone biomarkers were similar in both groups. Mean arterial blood pressure (MAP), central systolic and diastolic brachial blood pressure, heart rate, and pulse pressure were higher in the group with acPWV > 8.8 m/s than in the group with acPWV ≤ 8.8 m/s. The mortality was higher for patients with acPWV > 8.8 m/s at any given time over 28 months of follow-up. In multivariable analysis, predictors of higher acPWV were age >60.5, higher pulse rate, and higher central systolic or brachial diastolic blood pressure.

CONCLUSIONS

According to our results, we advise the measurement of acPWV preferentially in younger dialysis patients for prognosis, as well as intervention planning before the development of irreversible changes in blood vessels. In addition, measuring central systolic blood pressure seems to be useful for monitoring AS in prevalent hemodialysis patients.

A comparative study of ambulatory central hemodynamics and arterial stiffness parameters in peritoneal dialysis and hemodialysis patients

BACKGROUND

Ambulatory pulse-wave velocity (PWV), augmentation pressure, and augmentation index (AIx) are associated with increased cardiovascular events and death in hemodialysis. The intermittent nature of hemodialysis generates a distinct ambulatory pattern, with a progressive increase of augmentation pressure and AIx during the interdialytic interval. No study so far has compared the ambulatory course of central hemodynamics and PWV between peritoneal dialysis and hemodialysis patients.

METHODS

Thirty-eight patients under peritoneal dialysis and 76 patients under hemodialysis matched in a 1 : 2 ratio for age, sex and dialysis vintage underwent 48-h ambulatory blood pressure (BP) monitoring with the oscillometric Mobil-O-Graph device. Parameters of central hemodynamics [central SBP, DBP and pulse pressure (PP)], wave reflection [AIx, heart rate-adjusted AIx; AIx(75) and augmentation pressure] and PWV were estimated from the 48-h recordings.

RESULTS

Over the total 48-h period, no significant differences were observed between peritoneal dialysis and hemodialysis patients in mean levels of central SBP, DBP, PP, augmentation pressure, AIx, AIx(75) and PWV. However, patients under peritoneal dialysis and hemodialysis displayed different trajectories in all the above parameters over the course of the recording: in peritoneal dialysis patients no differences were noted in central SBP (125.0 ± 19.2 vs. 126.0 ± 17.8 mmHg, P = 0.25), DBP, PP, augmentation pressure (13.0 ± 6.8 vs. 13.7 ± 7. mmHg, P = 0.15), AIx(75) (25.9 ± 6.9 vs. 26.3 ± 7.8%, P = 0.54) and PWV (9.5 ± 2.1 vs. 9.6 ± 2.1 m/s, P = 0.27) from the first to the second 24-h period of the recording. In contrast, hemodialysis patients showed significant increases in all these parameters from the first to second 24 h (SBP: 119.5 ± 14.4 vs. 124.6 ± 15.0 mmHg, P < 0.001; augmentation pressure: 10.9 ± 5.3 vs. 13.1 ± 6.3 mmHg, P < 0.001; AIx(75): 24.7 ± 7.6 vs. 27.4 ± 7.9%, P < 0.001; PWV: 9.1 ± 1.8 vs. 9.3 ± 1.8 m/s, P < 0.001). Peritoneal dialysis patients had numerically higher levels than hemodialysis patients in all the above parameters during all periods studied and especially during the first 24-h.

CONCLUSION

Central BP, wave reflection indices and PWV during a 48-h recording are steady in peritoneal dialysis but gradually increase in hemodialysis patients. During all studied periods, peritoneal dialysis patients have numerically higher levels of all studied parameters, a fact that could relate to higher cardiovascular risk.