Arterial stiffness and pulse pressure in CKD and ESRD

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.

Association between serum elastin-derived peptides and abdominal aortic calcification in peritoneal dialysis patients: a cross-sectional study

Background

Peritoneal dialysis (PD) patients experience accelerated arterial aging, which is characterized by elastin degradation. Elastin-derived peptides (EDPs) are direct products of elastin fragmentation. This study tried to explore the association between serum EDPs and abdominal aortic calcification (AAC) in PD patients.

Methods

Serum levels of EDPs were analyzed in 126 eligible PD patients and 30 controls. PD patients were grouped according to the annularity of AAC evaluated by an abdominal computed tomography (CT) scan. Serum EDPs were analyzed in relation to the presence of AAC or severe AAC in PD patients by logistic regression analysis.

Results

Serum EDPs in PD patients were significantly higher than age-matched controls. In 126 PD patients, higher EDPs was associated with greater risk of present AAC (OR = 1.056, 95%CI 1.010–1.103) and severe AAC (OR = 1.062, 95%CI 1.004–1.123). A combination of EDPs substantially improved the accuracy of diagnostic performance for AAC and severe AAC.

Conclusions

EDPs can predict the presence and extent of AAC in PD patients, indicating its possible role to recognize PD patients at risk for AAC and severe AAC.

Role of arterial impairment in preeclampsia: should the paradigm shift?

Preeclampsia is a worldwide pregnancy complication with serious short- and long-term maternal and neonatal consequences. Our understanding of preeclampsia pathophysiology has significantly evolved over the last decades with the recognition that impaired arterial function and structure may occur early in the course of pregnancy, preceding the clinic-humoral syndrome and driving long-term cardiovascular disease risk in the future of these patients. Although an early abnormal placentation may be the inciting event for a large proportion of cases, there is growing evidence that challenges the placental hypothesis in all affected women, since placental histopathology lesions thought to be characteristic are neither sensitive nor specific markers for the disorder. Recent hemodynamic investigations and studies on left ventricular function and structure in women with preeclampsia further challenge this universal paradigm and propose that placental dysfunction could be secondary to a maternal cardiovascular maladaptation to pregnancy in certain patients. Supporting this hypothesis, certain vascular features, which are characteristically enhanced in normal pregnancy allowing a healthy vascular adaptation, are absent in preeclampsia and comparable to the nonpregnant population. However, arterial biomechanics in preeclampsia may only not cope with hemodynamic demands of pregnancy but also impose additional detrimental loads to the maternal heart ("impaired left-ventricle-aorta coupling") and transmit pressure and flow disturbances into the fetoplacental circulation ("impaired large arteries-microcirculation coupling"). In this review, we analyze the major role of the arterial dysfunction in the cardiovascular maladaptation hypothesis of preeclampsia, shed light on its potential etiopathogenic link, and discuss the complementary nature of the placental and cardiovascular theories.

Cardiovascular Risk Factor Profiles and Disease in Black Compared to Other Africans with Chronic Kidney Disease

Methods

Cardiovascular risk factors, aortic and cardiac function, atherosclerosis extent, and cardiovascular event rates were assessed in 115 consecutive predialysis (n = 67) and dialysis patients (n = 48) including 46 black and 69 other (32 Asian, 28 white, and 9 mixed race) participants. Data were analysed in multivariable regression models.

Results

Overall, black compared to other African CKD patients had less frequent carotid artery plaque (OR (95% CI) = 0.38 (0.16–0.91)) despite an increased cardiovascular risk factor burden. In receiver operator characteristic curve analysis, the Framingham score performed well in identifying non-black but not black CKD patients with carotid plaque (area under the curve (AUC) (95% CI) = 0.818 (0.714–0.921) and AUC (95% CI) = 0.556 (0.375–0.921), respectively). Black compared to other African predialysis patients experienced larger Framingham scores and more adverse nontraditional cardiovascular risk factors, impaired arterial and diastolic function but similar cardiovascular event rates (OR (95% CI) = 0.93 (0.22 to 3.87)). Among dialysis patients, black compared to other Africans had an overall similar traditional and nontraditional cardiovascular risk factor burden, similar arterial and diastolic function but increased systolic function (partial R = 0.356, p = 0.01 and partial R = 0.315, p = 0.03 for ejection fraction and stroke volume, respectively) and reduced cardiovascular event rates (OR (95% CI) = 0.22 (0.05 to 0.88)).

Conclusion

Black compared to other African CKD patients have less frequent very high risk atherosclerosis and experience weaker cardiovascular risk factor-atherosclerotic CVD relationships. These disparities may be due to differences in epidemiological health transition stages. Among dialysis patients, black compared to other Africans have less cardiovascular events, which may represent a selection bias as previously documented in black Americans.

Age dependence of brachial cuff-based ambulatory PWV in end-stage kidney disease patients undergoing long-term peritoneal dialysis

BACKGROUND

The newly introduced device Mobil-O-Graph (IEM, Stolberg, Germany) combines brachial cuff oscillometry and pulse wave analysis, enabling the determination of pulse wave velocity (PWV) via complex mathematic algorithms during 24-h ambulatory blood pressure monitoring (ABPM). However, the determinants of oscillometric PWV in the end-stage kidney disease (ESKD) population remain poorly understood.

METHODS

In this study, 81 ESKD patients undergoing long-term peritoneal dialysis underwent 24-h ABPM with the Mobil-O-Graph device. The association of 24-h oscillometric PWV with several demographic, clinical and haemodynamic parameters was explored using linear regression analysis.

RESULTS

In univariate analysis, among 21 risk factors, 24-h PWV exhibited a positive relationship with age, body mass index, overhydration assessed via bioimpedance spectroscopy, diabetic status, history of dyslipidaemia and coronary heart disease, and it had a negative relationship with female sex and 24-h heart rate. In stepwise multivariate analysis, age (β: 0.883), 24-h systolic blood pressure (BP) (β: 0.217) and 24-h heart rate (β: -0.083) were the only three factors that remained as independent determinants of 24-h PWV (adjusted R ² = 0.929). These associations were not modified when all 21 risk factors were analysed conjointly or when the model included only variables shown to be significant in univariate comparisons.

CONCLUSION

The present study shows that age together with simultaneously assessed oscillometric BP and heart rate are the major determinants of Mobil-O-Graph-derived PWV, explaining >90% of the total variation of this marker. This age dependence of oscillometric PWV limits the validity of this marker to detect the premature vascular ageing, a unique characteristic of vascular remodelling in ESKD.

The Association of Glomerular Filtration Rate With Echocardiographic Parameters in Chronic Kidney Disease

Background

Cardiovascular disease (CVD) is the primary cause of mortality and morbidity in chronic kidney disease (CKD) patients. Aortic propagation velocity (APV), epicardial fat thickness (EFT) and carotid intima-media thickness (CIMT) measurements could provide additional information on assessing renal decline in CKD patients. The study aimed to evaluate EFT, AVP and CIMT in CKD patients and then investigate the association among those parameters.

Methods

A total of 170 CKD consecutive subjects were enrolled in the study. Patients were divided into five groups according to their estimated glomerular filtration rate (eGFR) values. Each patient underwent complete transthoracic echocardiography examination. APV, EFT and CIMT were measured for analyses. A multivariate linear regression model was used for analysis to determine the independent predictors of eGFR.

Results

The lowest APV was observed in stage IV-V, and the highest APV was observed in stage I-II (P < 0.001). Stage IV-V patients had the highest EFT and stage I-II patients had the lowest EFT (P < 0.001). Moreover, the lowest CIMT was observed in stage III, and the highest CIMT was observed in stage V (P < 0.001). eGFR was significantly and positively correlated with APV and negatively correlated with EFT and CIMT. In multivariate analyses, APV (odds ratio (OR): 0.289, P < 0.001), EFT (OR: -0.135, P < 0.001) and CIMT (OR: -0.388, P < 0.001) were independent predictors of eGFR.

Conclusion

We found that APV decreased, and EFT and CIMT increased as CKD progress. The present study suggests that APV, EFT and CIMT might be incorporated with the examination of CKD patients in daily practice.

Positive Associations between Adipocyte Fatty Acid-Binding Protein Level and Central Arterial Stiffness in Peritoneal Dialysis Patients

Background

Adipocyte fatty acid-binding protein (A-FABP) plays essential roles in lipolysis, insulin resistance, and atherosclerosis. This study aimed to evaluate the relationship between serum A-FABP levels and carotid-femoral pulse wave velocity (cfPWV) in peritoneal dialysis (PD) patients.

Methods

This study obtained fasting blood samples from 76 PD patients. A validated tonometry system was used to measure cfPWV. Patients with cfPWV values >10 m/s were classified into the high arterial stiffness group, whereas patients with values ≤10 m/s were classified into the low arterial stiffness group, according to the ESH-ESC 2013 guidelines. Serum A-FABP levels were measured using a commercial enzyme-linked immunosorbent assay kit.

Results

Twenty-five (32.9%) of the 76 PD patients were classified in the high arterial stiffness group. Compared with the patients in the low arterial stiffness group, the high arterial stiffness group was older (P = 0.002) and had a longer PD vintage (P = 0.011), higher diastolic blood pressure (DBP, P = 0.036), higher fasting glucose levels (P = 0.012), higher serum C reactive protein levels (P = 0.001), and higher serum A-FABP levels (P < 0.001). A multivariate logistic regression analysis of the factors significantly associated with central arterial stiffness revealed that A-FABP (odds ratio (OR): 1.165, 95% confidence interval (CI): 1.056–1.284, P = 0.002), age (OR: 1.423, 95% CI: 1.153–1.757, P = 0.001), PD vintage (OR: 1.049, 95% CI: 1.015–1.085, P = 0.005), and DBP (OR: 1.152, 95% CI: 1.033–1.285, P = 0.011) were independent predictors of central arterial stiffness in PD patients. Furthermore, serum A-FABP levels (β = 0.476, adjusted R² change: 0.197, P < 0.001) were significantly positively correlated with cfPWV according to the multivariable forward stepwise linear regression analysis.

Conclusions

A-FABP levels are an independent marker of central arterial stiffness in PD patients.

Aortic Elasticity Evaluated by Pulsed Tissue Doppler Imaging of the Ascending Aorta in Different Diseases: A Systematic Review

Several methods have been applied for the evaluation of aortic elasticity. Pulsed tissue Doppler imaging of the ascending aorta is a noninvasive method applied for the evaluation of aortic elasticity in wide variety of diseases which are reviewed in this study. A comprehensive systematic literature search was carried out in November 2019 using the English databases including PubMed, Scopus, Science Direct, and Embase. All references of eligible articles and published reviews on tissue Doppler imaging were searched for relevant publications. Data were extracted according to predefined criteria (including country of study origin, patient population, number of patients in case and control groups, and results of aortic elasticity evaluation in the specific patient groups compared with controls). Two independent reviewers extracted the data, and the results were checked, compared, and edited by the third reviewer. No formal assessment of the statistics of the primary data was made. The results showed that decreased aortic elasticity is not only present in cardiovascular diseases but also can be identified in diseases of other systems that affect cardiovascular system.

The Optimal Haemoglobin Target in Dialysis Patients May Be Determined by Its Contrasting Effects on Arterial Stiffness and Pressure Pulsatility

Introduction

It remains unclear why the optimal haemoglobin target is lower in patients with chronic kidney disease (CKD) than in non-CKD persons. Arteriosclerosis and consequent impaired arterial function comprise a central cardiovascular risk mechanism in CKD. We hypothesized that the optimal haemoglobin target depends on its opposing effects on arterial stiffness and pressure pulsatility in CKD.

Methods

Arterial stiffness (aortic pulse wave velocity), wave reflection (augmentation index, reflected wave pressure and reflection magnitude), and pressure pulsatility (central systolic and pulse pressure, peripheral pulse pressure, pressure amplification and forward wave pressure) were assessed in 48 dialysis patients.

Results

In established confounder and diabetes adjusted linear regression models, haemoglobin levels were directly associated with arterial stiffness (partial R=0.366, p=0.03) and inversely with central systolic pressure (partial R=−0.344, p=0.04), central pulse pressure (partial R=−0.403, p=0.01), peripheral pulse pressure (partial R=−0.521, p=0.001) and forward wave pressure (partial R=−0.544, p=0.001). The presence of heart failure and use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers and erythropoietin stimulating agents did not materially alter these relationships upon further adjustment for the respective characteristics in the models, and in sensitivity analyses. In receiver operator characteristic curve analysis, the optimal haemoglobin concentration cut-off values in predicting arterial stiffness and increased central pulse pressure were remarkably similar at 10.95 g/dl and 10.85 g/dl, respectively, and with clinically useful sensitivities, specificities and positive and negative predictive values. In logistic regression models, a haemoglobin value of >10.9 mg/dl was associated with both arterial stiffness (>10 m/sec; OR (95% CI) = 10.48 (1.57–70.08), p=0.02) and normal central pulse pressure (>50 mmHg; OR (95% CI) = 7.55 (1.58–36.03), p=0.01).

Conclusion

This study suggests that the optimal haemoglobin target in dialysis patients is ~11g/dl and determined by its differential and contrasting effects on arterial stiffness and pressure pulsatility.

Fibrosis in Chronic Kidney Disease: Pathogenesis and Consequences

Fibrosis is a process characterized by an excessive accumulation of the extracellular matrix as a response to different types of tissue injuries, which leads to organ dysfunction. The process can be initiated by multiple and different stimuli and pathogenic factors which trigger the cascade of reparation converging in molecular signals responsible of initiating and driving fibrosis. Though fibrosis can play a defensive role, in several circumstances at a certain stage, it can progressively become an uncontrolled irreversible and self-maintained process, named pathological fibrosis. Several systems, molecules and responses involved in the pathogenesis of the pathological fibrosis of chronic kidney disease (CKD) will be discussed in this review, putting special attention on inflammation, renin-angiotensin system (RAS), parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), Klotho, microRNAs (miRs), and the vitamin D hormonal system. All of them are key factors of the core and regulatory pathways which drive fibrosis, having a great negative kidney and cardiac impact in CKD.

Arterial Stiffness and Hypertension in the Elderly

Hypertension prevalence increases with age. Age and high blood pressure are the two main determinants of arterial stiffness. In elderly hypertensives, large arteries stiffen and systolic and pulse pressures increase, due to wave reflections. A major reason for measuring arterial stiffness in clinical practice in elderly hypertensive patients comes from the repeated demonstration that arterial stiffness and wave reflections have a predictive value for CV events. A large body of evidence has been published during the last two decades, concerning the epidemiology, pathophysiology, and pharmacology of large arteries in hypertension in various settings of age. Particularly, two expert consensus documents have reviewed the methodological agreements for measuring arterial stiffness. The concepts of Early Vascular Aging (EVA) and Supernormal Vascular Aging (SUPERNOVA) help to better understand on which determinants of arterial stiffness it is possible to act, in order to limit target organ damage and cardiovascular complications. This review will address the issues of the cellular and molecular mechanisms of arterial stiffening in elderly hypertensives, the consequences of arterial stiffening on central systolic and pulse (systolic minus diastolic, PP) pressures and target organs, the methodology for measuring arterial stiffness, central pulse pressure and wave reflection, the epidemiological determinants of arterial stiffening in elderly hypertensives, the pharmacology of arterial destiffening, and how the concepts of EVA and SUPERNOVA apply to the detection of organ damage and prevention of CV complications.

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.

Aortic pulse wave velocity, central pulse pressure, augmentation index and chronic kidney disease progression in individuals with type 2 diabetes: a 3- year prospective study

BACKGROUND

Pulse wave velocity (PWV), central pulse pressure and augmentation index are arterial stiffness- related hemodynamic parameters but their associations with renal outcome are still controversial. We hereby aim to study, 1) which hemodynamic parameter is independently associated with progressive chronic kidney disease (CKD), 2) the association of 3-year change in PWV with CKD progression and, 3) the additive predictive value of PWV for progressive CKD.

METHODS

Carotid- femoral PWV, central pulse pressure and augmentation index were measured in 1444 participants with type 2 diabetes at baseline and 3 years apart. Progressive CKD was defined as confirmed eGFR decline 40% or greater.

RESULTS

In the follow-up, 102 participants experienced progressive CKD. All 3 hemodynamic parameters were significantly associated with progressive CKD In univariable analysis. However, only PWV remained statistically significant after adjustment for known clinical risk factors and the other 2 hemodynamic parameters (OR 1.14 [95% CI 1.01-1.29] per m/s increment). One m/s regression (decrement) in PWV in the 3-year follow-up was associated with 26% lower adjusted- risk of progressive CKD (OR 0.74, 95% CI 0.56-0.97). Adding PWV onto traditional risk factor- based model significantly improved classification (net reclassification improvement 0.25, 95% CI 0.05-0.45, P = 0.01) and positive prediction rate (24.5 to 32.3%).

CONCLUSIONS

Of 3 arterial stiffness- related hemodynamic parameters, only PWV is independently associated with progressive CKD. PWV may be a potential intervention target to mitigate risk of CKD progression and also a biomarker to improve risk-stratification of adverse renal outcome in individuals with type 2 diabetes.

Relationship between high-normal albuminuria and arterial stiffness in Chinese population

High-normal albuminuria is related to the morbidity and mortality of cardiovascular disease. Arterial stiffness has been regarded as a predictor of cardiovascular disease. However, the relationship between high-normal albuminuria and arterial stiffness is uncertain in Chinese population. A total of 1343 Chinese participants (aged 58.9 ± 12.1 years, 63.53% male) were included in this study. High-normal albuminuria was defined as urinary albumin-to-creatinine ratio (UACR) above the median within normal albuminuria. Based on the level of UACR, all participants were divided into low-normal albuminuria group (UACR < 6.36 mg/g, n = 580), high-normal albuminuria group (6.36 mg/g ≤ UACR < 30 mg/g, n = 581), microalbuminuria (30 mg/g ≤ UACR < 300 mg/g, n = 162), and macroalbuminuria (UACR ≥ 300 mg/g, n = 20). Arterial stiffness was assessed by measuring carotid-femoral pulse wave velocity (cfPWV). With the increment of UACR, the level of cfPWV was increased gradually (P < .001). Stepwise multiple regression analysis showed that systolic blood pressure, age, serum creatinine, heart rate, logarithmic (LG)-transformed UACR, and fasting plasma glucose were independently associated with cfPWV in all subjects (P < .001). LG-UACR was found to be related to cfPWV in high-normal albuminuria and macroalbuminuria subjects. After further stratification in the high-normal albuminuria subjects, their relation remained in male, elderly over 65 years old, or normotensives. In summary, UACR is associated with arterial stiffness in subjects with proteinuria excretion in high normal level. High-normal albuminuria might be an early indicator of arterial stiffness, especially in male, elderly, or normotensives in Chinese population. Furthermore, age and blood pressure are still observed to be the most important risk factor of arterial stiffness.

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.

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

OBJECTIVES

Hemodialysis patients have premature arterial stiffness, and the relationship between pulse wave velocity (PWV) and blood pressure (BP) may be different than in other hypertensives. Previous studies in such patients showed that when BP decrease is accompanied by PWV decrease the survival is improved. This study examines the prognostic role of the mean BP (MBP)-PWV association for cardiovascular outcomes and all-cause mortality in hemodialysis.

METHODS

A total of 242 hemodialysis patients underwent 48-h ambulatory BP monitoring with Mobil-O-Graph-NG and were followed for 33.17 ± 19.68 months. The within-individual MBP-PWV association (MBP, dependent and PWV independent variable) was evaluated using the β-coefficient value from simple linear regression analysis for each patient. The primary end-point was first occurrence of all-cause death, nonfatal myocardial infarction or nonfatal stroke. Secondary end-points were all-cause mortality, cardiovascular mortality and a combination of cardiovascular events.

RESULTS

Higher quartiles of β-coefficients (indicating strong within-individual association of MBP with PWV) were related to greater cumulative freedom from the primary end-point (50.8, 60.0, 70.0 and 80.3% for quartiles 1-4, respectively; log-rank P = 0.001), better overall survival (60.7, 61.7, 73.3, 86.9%; log-rank P = 0.002) and better cardiovascular survival (78.7, 75.0, 81.7, 91.8% for quartiles 1-4; log-rank P = 0.044). The future risks of the primary end-point, all-cause and cardiovascular mortality and the combined outcome were progressively increasing with lower quartiles of β-coefficients, indicating patients with weak MBP-PWV association (hazard ratios for all-cause mortality 3.395; 95% confidence interval: 1.524-7.563, P = 0.003 for quartile 1 vs. quartile 4).

CONCLUSION

Weaker within-individual MBP-PWV association, based on ABPM recordings, is associated with higher risk of death and cardiovascular events in hemodialysis. These findings support that arterial stiffness insensitive to BP changes is the underlying factor for adverse outcomes in these individuals.

Transition of metabolic phenotypes and risk of subclinical atherosclerosis according to BMI: a prospective study

AIMS/HYPOTHESIS

The cardiometabolic risk associated with metabolically healthy obesity (MHO) remains the subject of debate. It is unclear whether MHO is a transient condition that affects subclinical atherosclerosis risk. In this study, we aimed to investigate the association of MHO and its transition over time with incident subclinical atherosclerosis.

METHODS

A prospective study was conducted with 6220 Chinese adults who were free of cardiovascular disease (CVD) at baseline. Obesity was defined as BMI ≥25.0 kg/m². Metabolic health was defined as an individual having fewer than two of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP ATP III) criteria for components of the metabolic syndrome (excluding waist circumference). Subclinical atherosclerosis was measured by brachial-ankle pulse wave velocity, pulse pressure and albuminuria, separately or combined. Participants were cross-classified by BMI categories and by metabolic health status and its transition during follow-up. Inverse probability weighted logistic regression models were used to estimate ORs and 95% CIs for subclinical atherosclerosis.

RESULTS

The MHO phenotype accounted for 16.3% of the total population and 32.8% of the population with obesity at baseline. Baseline MHO was not significantly associated with incident subclinical atherosclerosis. During a follow-up period of 4.4 years, 46.8% of individuals with MHO developed a metabolically unhealthy status. Those with transient MHO had an increased risk of composite subclinical atherosclerosis compared with those in the metabolically healthy non-obesity reference group (OR 2.52 [95% CI 1.89, 3.36]). A transition from metabolically unhealthy to healthy status was shown to decrease the outcome risk. The relationship between BMI and subclinical atherosclerosis was partly mediated by BP and plasma glucose.

CONCLUSIONS/INTERPRETATION

MHO is not a stable condition and transient MHO conferred an increased risk of subclinical atherosclerosis, the early stage of CVD. Hence, individuals may benefit from early behavioural or medical management in order to avoid a deterioration of metabolic status and prevent atherosclerosis and CVD.

Impact of Kidney Disease on Peripheral Arterial Interventions: A Systematic Review and Meta-Analysis

BACKGROUND

There are limited data on outcomes of patients undergoing peripheral arterial disease (PAD) interventions who have comorbid CKD/ESRD versus those who do not have such comorbid condition. We performed a systematic review and meta-analysis to analyze outcomes in this patient population.

METHODS

Five databases were searched for studies comparing outcomes of lower extremity PAD interventions for claudication and critical limb ischemia (CLI) in patients with CKD/ESRD versus non-CKD/non-ESRD from January 2000 to June 2019.

RESULTS

Our study included 16 observational studies with 44,138 patients. Mean follow-up was 48.9 ± 27.4 months. Major amputation was higher with CKD/ESRD compared with non-CKD/non-ESRD (odds ratio [OR 1.97] [95% confidence interval [CI] 1.39-2.80], p = 0.001). Higher major amputations with CKD/ESRD versus non-CKD/non-ESRD were only observed when indication for procedure was CLI (OR 2.27 [95% CI 1.53-3.36], p < 0.0001) but were similar for claudication (OR 1.15 [95% CI 0.53-2.49], p = 0.72). The risk of early mortality was high with CKD/ESRD patients undergoing PAD interventions compared with non-CKD/non-ESRD (OR 2.55 [95% CI 1.65-3.96], p < 0.0001), which when stratified based on indication, remained higher with CLI (OR 3.14 [95% CI 1.80-5.48], p < 0.0001) but was similar with claudication (OR 1.83 [95% CI 0.90-3.72], p = 0.1). Funnel plot of included studies showed moderate bias.

CONCLUSIONS

Patients undergoing lower extremity PAD interventions for CLI who also have comorbid CKD/ESRD have an increased risk of experiencing major amputations and early mortality. Randomized trials to understand outcomes of PAD interventions in this at-risk population are essential.

Upstroke Time as a Novel Predictor of Mortality in Patients with Chronic Kidney Disease

Upstroke time (UT), measured from the foot-to-peak peripheral pulse wave, is a merged parameter used to assess arterial stiffness and target vascular injuries. In this study, we aimed to investigate UT for the prediction of cardiovascular and all-cause mortality in patients with chronic kidney disease (CKD). This longitudinal study enrolled 472 patients with CKD. Blood pressure, brachial pulse wave velocity (baPWV), and UT were automatically measured by a Colin VP-1000 instrument. During a median follow-up of 91 months, 73 cardiovascular and 183 all-cause mortality instances were recorded. Multivariable Cox analyses indicated that UT was significantly associated with cardiovascular mortality (hazard ratio (HR) = 1.010, p = 0.007) and all-cause mortality (HR = 1.009, p < 0.001). The addition of UT into the clinical models including traditional risk factors and baPWV further increased the value in predicting cardiovascular and all-cause mortality (both p < 0.001). In the Kaplan–Meier analyses, UT ≥ 180 ms could predict cardiovascular and all-cause mortality (both log-rank p < 0.001). Our study found that UT was a useful parameter in predicting cardiovascular and all-cause mortality in CKD patients. Additional consideration of the UT might provide an extra benefit in predicting cardiovascular and all-cause mortality beyond the traditional risk factors and baPWV.

Circulating let-7g-5p and miR-191-5p Are Independent Predictors of Chronic Kidney Disease in Hypertensive Patients

BACKGROUND

Hypertension (HTN) is associated with target organ damage such as cardiac, vascular, and kidney injury. Several studies have investigated circulating microRNAs (miRNAs) as biomarkers of cardiovascular disease, but few have examined them as biomarker of target organ damage in HTN. We aimed to identify circulating miRNAs that could serve as biomarkers of HTN-induced target organ damage using an unbiased approach.

METHODS AND RESULTS

Fifteen normotensive subjects, 16 patients with HTN, 15 with HTN associated with other features of the metabolic syndrome (MetS), and 16 with HTN or chronic kidney disease (CKD) were studied. Circulating RNA extracted from platelet-poor plasma was used for small RNA sequencing. Differentially expressed (DE) genes were identified with a threshold of false discovery rate <0.1. DE miRNAs were identified uniquely associated with HTN, MetS, or CKD. However, only 2 downregulated DE miRNAs (let-7g-5p and miR-191-5p) could be validated by reverse transcription-quantitative PCR. Let-7g-5p was associated with large vessel stiffening, miR-191-5p with MetS, and both miRNAs with estimated glomerular filtration rate (eGFR) and neutrophil and lymphocyte fraction or number and neutrophil-to-lymphocyte ratio. Using the whole population, stepwise multiple linear regression generated a model showing that let-7g-5p, miR-191-5p, and urinary albumin/creatinine ratio predicted eGFR with an adjusted R2 of 0.46 (P = 8.5e-7).

CONCLUSIONS

We identified decreased circulating let-7g-5p and miR-191-5p as independent biomarkers of CKD among patients with HTN, which could have pathophysiological and therapeutic implications.

Large-Artery Stiffness in Health and Disease: JACC State-of-the-Art Review

A healthy aorta exerts a powerful cushioning function, which limits arterial pulsatility and protects the microvasculature from potentially harmful fluctuations in pressure and blood flow. Large-artery (aortic) stiffening, which occurs with aging and various pathologic states, impairs this cushioning function, and has important consequences on cardiovascular health, including isolated systolic hypertension, excessive penetration of pulsatile energy into the microvasculature of target organs that operate at low vascular resistance, and abnormal ventricular-arterial interactions that promote left ventricular remodeling, dysfunction, and failure. Large-artery stiffness independently predicts cardiovascular risk and represents a high-priority therapeutic target to ameliorate the global burden of cardiovascular disease. This paper provides an overview of key physiologic and biophysical principles related to arterial stiffness, the impact of aortic stiffening on target organs, noninvasive methods for the measurement of arterial stiffness, mechanisms leading to aortic stiffening, therapeutic approaches to reduce it, and clinical applications of arterial stiffness measurements.

Plasma Endothelin-1 and Risk of Death and Hospitalization in Patients Undergoing Maintenance Hemodialysis

BACKGROUND AND OBJECTIVES

Endothelin-1 is a potent endothelium-derived vasoconstrictor peptide implicated in the pathogenesis of hypertension, congestive heart failure, and inflammation, all of which are critical pathophysiologic features of CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

To test the hypothesis that plasma endothelin-1 levels are associated with increased risks of mortality and hospitalization in patients with chronic kidney failure, we measured plasma endothelin-1 levels in a prospective cohort of 794 individuals receiving maintenance hemodialysis. The primary outcomes were time to death and time to hospitalization.

RESULTS

The median plasma endothelin-1 level was 2.02 (interquartile range, 1.57-2.71) pg/ml. During a median follow-up period of 28 (interquartile range, 21-29) months, 253 individuals (32%) died and 643 individuals (81%) were hospitalized at least once. In multivariable models adjusted for demographic, clinical, and laboratory variables, individuals in the highest quartile of plasma endothelin-1 had a 2.44-fold higher risk of death (hazard ratio, 2.44; 95% confidence interval, 1.61 to 3.70) and a 1.54-fold higher risk of hospitalization (hazard ratio, 1.54; 95% confidence interval, 1.19 to 1.99) compared with individuals in the lowest quartile. The Harrell C-statistic of the fully adjusted model increased from 0.73 to 0.74 after addition of natural log-transformed plasma endothelin-1 (P<0.001) for all-cause mortality, and increased from 0.608 to 0.614 after addition of natural log-transformed plasma endothelin-1 (P=0.002) for hospitalization.

CONCLUSIONS

Higher plasma endothelin-1 is associated with adverse clinical events in patients receiving hemodialysis independent of previously described risk factors.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_05_15_CJN11130919.mp3.

Arterial Stiffness Assessed by Oscillometric Method in Kidney Transplant, Predialysis, and Dialysis Patients

INTRODUCTION

Chronic kidney disease (CKD) is strongly associated with a higher risk of cardiovascular disease (CV). An important nontraditional risk factor of cardiovascular disease in renal patients is vascular stiffness, which currently can be evaluated by oscillometric measuring of pulse wave velocity (PWV) and heart rate-corrected augmentation index (AIx@75).

AIM

The aim of our study was to compare vascular stiffness between kidney transplant (KTx) recipients, patients on dialysis maintenance, and those in the predialysis period.

MATERIALS AND METHODS

A cross-sectional study of 140 patients (52 in CKD stage 3-4; 37 in CKD stage 5 on hemodialysis maintenance [HD]; and 51 KTx recipients) had their PWV and AIx@75 measured with Mobil-O-Graph (IEM Gmbh, Stolberg, Germany) blood and pulse pressure monitor.

RESULTS

KTx, HD, and CKD G3-4 were comparable in term of age, sex, body mass index, and diagnoses of diabetes mellitus and hypertension. The PWV was higher in the HD group than in the KTx and CKD G3-4 (9.4 m/s vs 8.4 m/s vs 7.9 m/s respectively; P < .05 for HD vs other groups), while the difference between the KTx and CKD G3-4 was not significant. AIx@75 values were similar in the HD and KTx groups (27.1 and 25.6; P > .05) and significantly lower in CDK G3-4 (17.8; P < .05).

CONCLUSIONS

According to our results, the highest CV risk expressed by PWV (vascular stiffness) was found in hemodialysis patients. Although patients with CKD 3-4 and after KTx showed comparable large artery stiffness, transplant recipients additionally showed higher stiffness in smaller arteries as measured by heart rate-corrected AIx.

The impact of chronic kidney disease on cerebral hemodynamics: A transcranial Doppler study

Chronic kidney disease (CKD) independently increases the risk of stroke and small vessel disease (SVD). This study compared SVD and a transcranial Doppler (TCD)-based marker of intracranial vascular resistance (pulsatility index, PI) in post-stroke patients with and without CKD. Between January 2015 and December 2017, 118 individuals with stable eGFR (50 with CKD) had cerebral MRI and TCD within three months of a stroke. The means of bilateral PI in anterior (anterior cerebral [ACA] and middle cerebral arteries [MCA]) and posterior vessels (posterior cerebral [PCA] and vertebral arteries [VA]) were computed. CKD strongly correlated with higher distal resistance (median CKD ACA PI 1.2, IQR 1.0 to 1.35 vs. controls 0.91 IQR 0.79 to 1.1 [p < 0.0001]; median MCA PI 1.14 IQR 1.03 to 1.39 vs. controls 0.93 IQR 0.79 to 1.1 [p < 0.0001]) and MRI SVD burden (median CKD SVD 4.98 × 10⁴ IQR 2.66 to 7.76 × 10⁴ voxels vs. controls median SVD 6.7 × 10³ IQR 2.4 to 24.0 × 10³ [p < 0.0001]). In conclusion, in patients with recent stroke, CKD is an independent determinant of increased intracranial vascular resistance in both anterior and posterior cerebral circulations. MRI SVD volume is significantly associated with anterior and posterior circulation PI.

Assessment of Arterial Stiffness in Patients With Resistant Hypertension: Additional Insights Into the Pathophysiology of This Condition?

BACKGROUND

Good understanding of the pathophysiological mechanism(s) of resistant hypertension (RH) and the relationship to vascular dysfunction is important for optimal blood pressure control.

METHODS AND RESULTS

The aim of this review article is to summarize the available data on the methods of arterial stiffness assessment, and their usefulness in RH. Several studies that provide information on the noninvasive methods of evaluation of arterial stiffness have been discussed; specifically, pulse wave velocity (PWV) and augmentation index (AIx) tests. Increased arterial stiffness, elevated AIx, and impaired endothelial function all act as indicators and predictors of cardiovascular events in patients with hypertension (HTN).

CONCLUSION

Our review suggests that PWV and AIx are impaired in patients with severe HTN. Early assessment of these characteristics can potentially be of value in patients with RH.

Cardiac calcium dysregulation in mice with chronic kidney disease

Cardiovascular complications are leading causes of morbidity and mortality in patients with chronic kidney disease (CKD). CKD significantly affects cardiac calcium (Ca²⁺) regulation, but the underlying mechanisms are not clear. The present study investigated the modulation of Ca²⁺ homeostasis in CKD mice. Echocardiography revealed impaired fractional shortening (FS) and stroke volume (SV) in CKD mice. Electrocardiography showed that CKD mice exhibited longer QT interval, corrected QT (QTc) prolongation, faster spontaneous activities, shorter action potential duration (APD) and increased ventricle arrhythmogenesis, and ranolazine (10 µmol/L) blocked these effects. Conventional microelectrodes and the Fluo‐3 fluorometric ratio techniques indicated that CKD ventricular cardiomyocytes exhibited higher Ca²⁺ decay time, Ca²⁺ sparks, and Ca²⁺ leakage but lower [Ca²⁺]_i transients and sarcoplasmic reticulum Ca²⁺ contents. The CaMKII inhibitor KN93 and ranolazine (RAN; late sodium current inhibitor) reversed the deterioration in Ca²⁺ handling. Western blots revealed that CKD ventricles exhibited higher phosphorylated RyR2 and CaMKII and reduced phosphorylated SERCA2 and SERCA2 and the ratio of PLB‐Thr17 to PLB. In conclusions, the modulation of CaMKII, PLB and late Na⁺ current in CKD significantly altered cardiac Ca²⁺ regulation and electrophysiological characteristics. These findings may apply on future clinical therapies.

Uric Acid and Arterial Stiffness

Hyperuricemia is usually associated with hypertension, diabetes mellitus, metabolic syndrome and chronic kidney disease. Accumulating data from epidemiological studies indicate an association of increased uric acid (UA) with cardiovascular diseases. Possible pathogenic mechanisms include enhancement of oxidative stress and systemic inflammation caused by hyperuricemia. Arterial stiffness may be one of the possible pathways between hyperuricemia and cardiovascular disease, but a clear relationship between increased UA and vascular alterations has not been confirmed. The review summarizes the epidemiological studies investigating the relationship between UA and arterial stiffness and highlights the results of interventional studies evaluating arterial stiffness parameters in patients treated with UA-lowering drugs.

Endothelins in cardiovascular biology and therapeutics

Cardiovascular disease is a major contributor to global morbidity and mortality and is the common end point of many chronic diseases. The endothelins comprise three structurally similar peptides of 21 amino acids in length. Endothelin 1 (ET-1) and ET-2 activate two G protein-coupled receptors - endothelin receptor type A (ET_A) and endothelin receptor type B (ET_B) - with equal affinity, whereas ET-3 has a lower affinity for ET_A. ET-1 is the most potent vasoconstrictor in the human cardiovascular system and has remarkably long-lasting actions. ET-1 contributes to vasoconstriction, vascular and cardiac hypertrophy, inflammation, and to the development and progression of cardiovascular disease. Endothelin receptor antagonists have revolutionized the treatment of pulmonary arterial hypertension. Clinical trials continue to explore new applications of endothelin receptor antagonists, particularly in treatment-resistant hypertension, chronic kidney disease and patients receiving antiangiogenic therapies. Translational studies have identified important roles for the endothelin isoforms and new therapeutic targets during development, in fluid-electrolyte homeostasis, and in cardiovascular and neuronal function. Novel pharmacological strategies are emerging in the form of small-molecule epigenetic modulators, biologics (such as monoclonal antibodies for ET_B) and possibly signalling pathway-biased agonists and antagonists.

Aortic stiffness is not only associated with structural but also functional parameters of retinal microcirculation

OBJECTIVE

The aim of the study was to test the hypothesis that alterations in large arteries are associated with microvascular remodelling and decreased retinal capillary blood flow.

METHODS

The study group comprised of 88 patients with essential hypertension and 32 healthy controls. Retinal microcirculation was evaluated by scanning laser Doppler flowmetry. Macrovascular changes were assessed on the basis of arterial stiffness measurement (carotid-femoral pulse wave velocity), its hemodynamic consequences (central pulse pressure, augmentation pressure, augmentation index) and intima media thickness of common carotid artery.

RESULTS

Pulse wave velocity was inversely correlated to mean retinal capillary blood flow in hypertensive patients (R = -0.32, p < 0.01). This relationship remained significant in multivariate regression analysis after adjustment for age, sex, central systolic blood pressure (BP) and body mass index (β = -31.27, p < 0.001). Lumen diameter (LD) of retinal arterioles was significantly smaller in hypertensive then normotensive subjects (79.4 vs. 83.8, p = 0.03). Central and brachial systolic, diastolic and mean BPs were significantly correlated with LD and outer diameter of retinal arterioles. The relationship between LD and central BPs remained significant in multivariate analysis (β = -0.15, p = 0.03 for cSBP; β = -0.22, p = 0.04 for cDBP; β = -0.21, p = 0.03 for cMBP). Moreover, in a subgroup with cardiac damage central and brachial pulse pressure were positively associated with retinal wall thickness, wall cross sectional area, and wall to lumen ratio.

CONCLUSION

In conclusion, the study provides a strong evidence that microcirculation is coupled with macrocirculation not only in terms of structural but also functional parameters.

Fibroblast growth factor 21; review on its participation in vascular calcification pathology

Vascular calcification (VC) is an independent cardiovascular event and also a complication commonly found in chronic kidney disease (CKD) and diabetic patients. The mechanisms underpinning pathophysiology of VC is yet to be fully understood. Nevertheless, certain processes are generally believed to participate in its onset and progression. VC pathology is characterized by disequilibrium in the amount of natural inhibitors and active inducers of VC process. The imbalance may favor ectopic deposition of calcium-phosphate in form of hydroxyapatite in media or intima tunica compartments of blood vessels. This eventually could trigger phenotypic switch of smooth muscle cells to osteoblasts related cells. Thus, VSMC phenotypic trans-differentiation is currently considered as one of the hallmarks of VC. At the moment, there is no approved treatment. Fibroblast growth factors (FGFs) are a protein family that participates in varieties of biological processes. More recently, FGF21 seems to be gaining more attention with recent findings showing its anti-calcifying efficacy. In this review, the aim is to point out specific processes involved in VC and also to highlight the participation of FGF21 in the pathology of vascular calcification.

Pulse Pressure and the Risk of End-Stage Renal Disease Among Chinese Adults in Singapore: The Singapore Chinese Health Study

Background Although hypertension is an established risk factor for chronic kidney disease, less is known about the relationship of pulse pressure (PP), a measure of arterial stiffness, with chronic kidney disease. We investigated the association of systolic blood pressure (BP), diastolic BP, PP, and mean arterial pressure with the risk of end-stage renal disease (ESRD) in the prospective population-based Singapore Chinese Health Study. Methods and Results We used data from 30 636 participants who had BP measured at ages 46 to 85 years during follow-up I interviews between 1999 and 2004. Information on lifestyle factors was collected at recruitment from 1993 to 1998, and selected factors were updated at follow-up I. We identified 463 ESRD cases over an average 11.3 years of follow-up I by linkage with the nationwide Singapore Renal Registry. Cox proportional hazards regression models were used to assess the relations between different BP indexes and ESRD risk. Each BP index was positively associated with ESRD when studied individually. However, when PP was included as a covariate, systolic and diastolic BP and mean arterial pressure were no longer associated with ESRD. Conversely, PP remained significantly associated with ESRD risk in a dose-dependent manner (Ptrend<0.001) after adjusting for systolic or diastolic BP. Compared with the lowest group (<45 mm Hg) of PP, the hazard ratio was 5.25 (95% CI, 3.52-7.84) for the highest group (≥85 mm Hg). The association between hypertension and ESRD risk was attenuated and no longer significant after adjusting for PP. Conclusions Our findings provide a basis for targeting reduction of arterial stiffness to decrease ESRD risk.

Inter-leg systolic blood pressure difference predicts cardiovascular events and mortality in incident hemodialysis patients

BACKGROUND

High inter-arm blood pressure difference, a marker of vascular disease, may be difficult to assess in hemodialysis patients with arm arteriovenous fistulae. We investigated if high inter-leg systolic blood pressure difference associates with cardiovascular events and increased mortality in hemodialysis patients.

METHODS

Among 118 incident Japanese dialysis patients, bilateral leg blood pressure, arm blood pressure, brachial-ankle pulse wave velocity, and ankle-brachial index were measured, and the relative risk associated with inter-leg systolic blood pressure difference and other indices of vascular status was analyzed.

RESULTS

During follow-up (median, 46 months), 18 deaths and 75 cardiovascular events occurred in 38 patients. Kaplan-Meier curves showed that higher inter-leg systolic blood pressure difference was associated with overall (log-rank 9.35, p = 0.002) and cardiovascular (log-rank 5.81, p = 0.02) mortality. The period from the start of dialysis therapy to the first cardiovascular event was shorter as inter-leg systolic blood pressure difference increased (log-rank 23.7, p < 0.0001). In Cox hazard models, inter-leg systolic blood pressure difference greater than median independently predicted deaths (relative risk, 3.8; 95% confidence interval, 1.3-13.9) and cardiovascular events (relative risk, 3.9; 95% confidence interval, 1.9-9.21) after adjustments for age, sex, nutritional status, and diabetes, whereas other indices were not related to the risks. For well-nourished, moderately malnourished, and severely malnourished patients, the cumulative number of cardiovascular events in the high-inter-leg systolic blood pressure difference patients were 4.96, 31.44, and 55.18 events per 100 patient-years.

CONCLUSIONS

Higher inter-leg systolic blood pressure difference associated with increased risk of mortality and cardiovascular events suggesting that wider application of inter-leg systolic blood pressure difference measurements may be warranted in hemodialysis patients.

Diagnostic Tests for Vascular Calcification

Vascular calcification (VC) is the heterogeneous endpoint of multiple vascular insults, which varies by arterial bed, the layer of the arterial wall affected, and is propagated by diverse cellular and biochemical mechanisms. A variety of in vivo and ex vivo techniques have been applied to the analysis of VC in preclinical studies, but clinical examination has principally relied on a number of noninvasive and invasive imaging modalities for detection and quantitation. Most imaging methods suffer from suboptimal spatial resolution, leading to the inability to distinguish medial from intimal VC and insufficient sensitivity to detect microcalcifications that are indicative of active mineral deposition and of vulnerable plaques which may be prone to rupture. Serum biomarkers lack specificity for VC and cannot discriminate pathology. Overall, uncertainties surrounding the sensitivity and specificity of different VC testing modalities, the absence of a clear cause-effect relationship, and lack of any evidence-based diagnostic or therapeutic protocols in relation to VC testing in chronic kidney disease has yielded weak or ungraded recommendations for their use in clinical practice. While VC is recognized as a key manifestation of chronic kidney disease-mineral and bone disorder and those with an increasing burden of VC are considered to be at higher cardiovascular risk, routine screening is not currently recommended.

Relationship between arterial stiffness and chronic kidney disease in patients with primary hypertension

To investigate the association of noninvasive indices of arterial stiffness with chronic kidney disease (CKD) in patients with primary hypertension, 547 (mean age 60 years, 63% males) hypertensive hospital inpatients were recruited, comprising 337 hypertensives without CKD and 210 hypertensives with CKD. Noninvasive arterial stiffness indices were obtained, including central arterial haemodynamics derived from the radial artery waveform using SphygmoCor V8.0 system, carotid-femoral pulse wave velocity (cfPWV), large and small artery elasticity indices (C1, C2 respectively). Intima-media thickness (IMT) was evaluated by ultrasonography. The diagnosis of CKD was assessed by the estimated glomerular filtration rate (eGFR) or urinary albumin creatinine ratio (ACR). Compared with hypertension without CKD, hypertensive patients with CKD were older, had higher central systolic blood pressure, cfPWV, and IMT (all P < 0.01). With decreasing eGFR, cfPWV and augmentation index adjusted to heart rate of 75 bpm increased progressively whereas C2 decreased (P < 0.05) in subjects with CKD. In the overall population, cfPWV showed a significant trend of a negative association with eGFR (P = 0.04) after adjusting for age, gender, and brachial systolic blood pressure. Multiple logistic analysis showed that 1 SD (3 m/s) increase in cfPWV entailed a 1.35 (95% Cl: 1.018-1.790) times higher likelihood of the presence of CKD even after adjustment for confounding factors. The association of arterial stiffness and CKD suggests that cfPWV may be a potential hemodynamic index to evaluate cardiovascular risk in CKD patients with primary hypertension.

Nutraceuticals as a potential adjunct therapy toward improving vascular health in CKD

Chronic kidney disease (CKD) is a major public health epidemic and increases risk for developing cardiovascular disease (CVD). Vascular dysfunction is a major independent risk factor toward increased risk for CVD in CKD. Several mechanisms have been postulated to result in vascular dysfunction in CKD, including oxidative stress-mediated inflammation by redox imbalance and reduced nitric oxide (NO) bioavailability and synthesis. Therefore, strategies that decrease oxidative stress and/or increase NO bioactivity may have major clinical implications toward improving vascular health and reducing the burden of CVD in CKD. Nutraceutical therapy in the form of polyphenols, dietary nitrates, or selective mitochondria-targeting therapies has recently been shown to improve vascular function by reducing oxidative stress and/or increasing NO bioavailability and synthesis. This review, therefore, highlights these three emerging nutraceuticals recently implicated in pathophysiological improvement of vascular function in CKD. This review also describes those pathophysiological mechanisms thought to be responsible for the beneficial effects on the vasculature and possible experimental considerations that may exist within human CKD populations. It is clear throughout this review that human-based mechanistic preclinical and health-related clinical studies are lacking regarding whether nutraceuticals do indeed improve vascular function in patients with CKD. As such, a comprehensive, detailed, and fully integrated understanding of nutraceuticals and vasculature function is necessary in patients with CKD. Many opportunities exist for original mechanistic and therapeutic discoveries and investigations on select nutraceuticals and their impact on vascular outcomes in patients with CKD, and these will remain exciting avenues of research in the future.

Prevalence and Sex-Specific Distribution of Cardiovascular Risk Factors in University Students in an Urban-Rural Environment of the Democratic Republic of the Congo

A recent qualitative study on health promotion in non-communicable diseases in Sub-Saharan University students suggested sex differences in knowledge and beliefs concerning a healthy lifestyle. However, the extent to which this is reflected in sex-specific distribution of cardiovascular risk factors among Sub-Saharan African students have not been fully evaluated. The objective of this study was to assess the prevalence and the sex-specific distribution of some modifiable cardiovascular risk factors among students at University of Kikwit in the Democratic Republic of the Congo. This cross-sectional descriptive study included 780 students (62.2% men) at the University of Kikwit between January and March of 2016. Data on physical measurements, lifestyle factors, and medical history were collected. The median age (interquartile range) of the students was 23 years (21-25 years). The modifiable cardiovascular risk factors identified were: alcohol consumption (53.1%), overweight (16.4%), general obesity (1.9%), abdominal obesity (10.4%), tobacco consumption (8.1%), hypertension (7.6%) and high pulse pressure (6.4%). Compared to women, men had a higher prevalence of hypertension (9.9 vs. 3.7%; p = 0.002), tobacco consumption (10.7 vs. 3.7%; p = 0.001), and alcohol consumption (58.4 vs. 44.4%; p < 0.001). In contrast, abdominal obesity was more predominant in women than in men (23.1 vs. 2.7%; p < 0.001). This study suggests a sex-specific distribution of several modifiable cardiovascular risk factors in students at the University of Kikwit. Design of sex-specific, student-targeted health promotion programs may be warranted to reduce the prevalence of risk factors and the subsequent burden of cardiovascular diseases.

Chronic Kidney Disease as a Risk Factor for Heart Failure With Preserved Ejection Fraction: A Focus on Microcirculatory Factors and Therapeutic Targets

Heart failure (HF) and chronic kidney disease (CKD) co-exist, and it is estimated that about 50% of HF patients suffer from CKD. Although studies have been performed on the association between CKD and HF with reduced ejection fraction (HFrEF), less is known about the link between CKD and heart failure with preserved ejection fraction (HFpEF). Approximately, 50% of all patients with HF suffer from HFpEF, and this percentage is projected to rise in the coming years. Therapies for HFrEF are long established and considered quite successful. In contrast, clinical trials for treatment of HFpEF have all shown negative or disputable results. This is likely due to the multifactorial character and the lack of pathophysiological knowledge of HFpEF. The typical co-existence of HFpEF and CKD is partially due to common underlying comorbidities, such as hypertension, dyslipidemia and diabetes. Macrovascular changes accompanying CKD, such as hypertension and arterial stiffening, have been described to contribute to HFpEF development. Furthermore, several renal factors have a direct impact on the heart and/or coronary microvasculature and may underlie the association between CKD and HFpEF. These factors include: (1) activation of the renin-angiotensin-aldosterone system, (2) anemia, (3) hypercalcemia, hyperphosphatemia and increased levels of FGF-23, and (4) uremic toxins. This review critically discusses the above factors, focusing on their potential contribution to coronary dysfunction, left ventricular stiffening, and delayed left ventricular relaxation. We further summarize the directions of novel treatment options for HFpEF based on the contribution of these renal drivers.

Investigation of Systolic Blood Pressure, Diastolic Blood Pressure, and Pulse Pressure in Living Kidney Donors After Donor Nephrectomy

Kidney transplants from living donors have increased, but few studies have examined the long-term risks of live donor nephrectomy. This is the first study to report the blood pressure (BP) changes associated with cardiovascular disease and linked to chronic kidney disease (CKD) 1 year after live donor nephrectomy. This study examined a prospective cohort of patients who underwent donor nephrectomy between March 1, 2006, and December 31, 2016, at the Severance Hospital, Seoul, South Korea. CKD was defined as a glomerular filtration rate (GFR) of < 60 mL/min/1.73m². Patients with a history of hypertension or CKD or an estimated GFR < 60 mL/min/1.73m² were excluded; those examined after 1 year post-nephrectomy were included in the study population. Among 420 patients who underwent donor nephrectomy, 137 (32.6%) developed a first-time onset of a GFR < 60 mL/min/1.73m² by the first year after surgery. After propensity score-matching the age, systolic BP (P < .001) and pulse pressure (P = .006) were significantly associated with the groups with newly developed CKD. Systolic BP and pulse pressure decreased significantly at 1 year after donor nephrectomy. These differences decreased after donor nephrectomy, possibly lowering the risk of cardiovascular disease.

Impact of Abdominal Aortic Calcification on Central Haemodynamics and Decline of Glomerular Filtration Rate in Patients with Chronic Kidney Disease Stages 3 and 4

BACKGROUND/AIM

Calcifications of large arteries are frequent in chronic kidney disease (CKD) and may contribute to the high cardiovascular risk in this population. The aim of this study was to examine whether abdominal aortic calcification volume (AACV) was a predictor of the rate of decline in glomerular filtration rate (GFR) in a cohort of patients with CKD stages 3 and 4.

METHODS

Eighty-four patients with CKD stages 3 and 4 were enrolled in this prospective observational study. At study entry, and annually, GFR was measured by plasma 51Cr-EDTA clearance. At baseline, haemodynamics was assessed and AACV was determined by computer tomography.

RESULTS

The mean follow-up time was 3.4 years and mean decline in GFR was -2.69 mL/min/1.73 m2 per year. At baseline, abdominal aortic calcification (AAC) was detected in 66 patients (79%). A binary logistic regression analysis revealed that age was the only statistically significant independent predictor of AAC. In patients with AAC, male gender (B = 0.413, p = 0.030), aortic diastolic blood pressure (B = -0.025, p = 0.001) and ankle-brachial index (B = -1.666, p = 0.002) were independently associated with AACV using a multiple linear regression analysis. Neither the presence nor the extent of AAC was significantly associated with the rate of change in GFR during follow-up.

CONCLUSION

In this cohort of patients with CKD stages 3 and 4, only age was an independent predictor of the presence of AAC. AACV was not associated with the rate of decline in GFR.

Arterial Stiffness Assessed by Cardio-Ankle Vascular Index

Arterial stiffness is an age-related disorder. In the medial layer of arteries, mechanical fracture due to fatigue failure for the pulsatile wall strain causes medial degeneration vascular remodeling. The alteration of extracellular matrix composition and arterial geometry result in structural arterial stiffness. Calcium deposition and other factors such as advanced glycation end product-mediated collagen cross-linking aggravate the structural arterial stiffness. On the other hand, endothelial dysfunction is a cause of arterial stiffness. The biological molecular mechanisms relating to aging are known to involve the progression of arterial stiffness. Arterial stiffness further applies stress on large arteries and also microcirculation. Therefore, it is closely related to adverse outcomes in cardiovascular and cerebrovascular system. Cardio-ankle vascular index (CAVI) is a promising diagnostic tool for evaluating arterial stiffness. The principle is based on stiffness parameter β, which is an index intended to assess the distensibility of carotid artery. Stiffness parameter β is a two-dimensional technique obtained from changes of arterial diameter by pulse in one section. CAVI applied the stiffness parameter β to all of the arterial segments between heart and ankle using pulse wave velocity. CAVI has been commercially available for a decade and the clinical data of its effectiveness has accumulated. The characteristics of CAVI differ from other physiological tests of arterial stiffness due to the independency from blood pressure at the time of examination. This review describes the pathophysiology of arterial stiffness and CAVI. Molecular mechanisms will also be covered.

Loss of the Normal Gradient in Arterial Compliance and Outcomes of Chronic Kidney Disease Patients

BACKGROUND

In dialysis patients, loss of the normal gradient in arterial compliance, assessed by the pulse wave velocity (PWV) ratio, predicts all-cause mortality better than does carotid-femoral PWV (CF-PWV) alone. However, the prognostic significance of the PWV ratio for outcome in chronic kidney disease (CKD) patients remains unclear.

METHODS

In this longitudinal cohort study, CKD patients who visited our CKD management clinic between April 27, 2006, and March 27, 2008, were included and followed up. To assess the gradient in arterial compliance, the PWV ratio was calculated using CF-PWV divided by carotid-radial PWV.

RESULTS

A total of 209 patients in CKD stages 1-4 with a median follow-up of 3.74 years were included. Patients with higher PWV ratio were relatively older (p < 0.001) and had worse renal function (p < 0.001), more hypertension (p < 0.001), diabetes mellitus (p < 0.001), and cardiovascular or cerebrovascular disease (p < 0.001). The median time to patient outcome (death, renal replacement therapy, or double increase in serum creatinine from baseline) in the group with a PWV ratio above the median (89.8 months, 95% CI 84.2-95.5) was shorter than that in the group with a PWV ratio below the median (105.3 months, 95% CI 101.3-109.3, p = 0.001). Univariate Cox regression analysis showed that both PWV ratio and CF-PWV were significantly associated with patient outcome. In multivariate Cox regression analysis, both PWV ratio and CF-PWV were associated with patient outcome. However, the HR for CF-PWV (2.177, 95% CI 1.064-4.453, p = 0.033) was slightly higher than that for PWV ratio (2.091, 95% CI 1.049-4.167, p = 0.036). There was a significant interaction effect between PWV ratio and CKD stage. It was shown that patients with advanced CKD stages and higher PWV ratios had a significantly higher risk of adverse CKD outcome (p = 0.006).

CONCLUSIONS

The PWV ratio, as a measure of loss of the normal gradient in arterial compliance, was associated with CKD patient outcome. Patients with advanced CKD and a higher PWV ratio had a significantly higher risk of adverse CKD outcome.

Histopathological and proteomic analyses identify integrin-β1 as a potential mediator of phlebosclerosis in uremic patients

BACKGROUND

Patients with uremia have an excessive mortality from cardiovascular disease (CVD). Arterial remodeling is mainly responsible for uremia-induced CVD and has been well studied, yet venous remodeling is poorly understood. Here we investigate the histopathology and proteomic profiles of venous remodeling in uremic patients.

METHODS

Forearm cephalic veins were isolated from nine uremic patients during surgeries for arteriovenous fistula, and from nine healthy controls when applying surgical debridement. Hematoxylin-eosin, Masson's trichrome, von Kossa, and immunohistochemistry (IHC) against proliferating cell nuclear antigen were stained for histopathology. Isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis was executed to explore the proteome of the veins. The core regulatory protein was validated by western blot, IHC, and immunofluorescence.

RESULTS

Phlebosclerosis, characterized by intimal rarefaction and medial thickening with disordered proliferation of vascular smooth muscle cells (VSMCs), was the prominent pathological manifestation of peripheral veins in uremic patients, while inflammatory cell infiltration, atherosclerosis or calcification were not obviously detected. iTRAQ analysis showed that 350 proteins were significantly changed in phlebosclerosis of uremic patients compared with healthy controls, of which integrin-β1 (ITGβ1) exhibited the strongest regulatory ability by intermolecular interaction network analysis. The enhanced ITGβ1 expression was mainly co-expressed with the disordered proliferation of VSMCs while a little with vascular endothelial cells in the forearm cephalic veins of uremic patients.

CONCLUSIONS

Phlebosclerosis is the prominent pathological manifestation in peripheral veins of uremic patients. This pathological alteration mainly attributes to the disordered proliferation of VSMCs, which is potentially mediated by ITGβ1.