Central pulse pressure and aortic stiffness determine renal hemodynamics: pathophysiological implication for microalbuminuria in hypertension

An In Silico Modelling Approach to Predict Hemodynamic Outcomes in Diabetic and Hypertensive Kidney Disease

Early diagnosis of kidney disease remains an unmet clinical challenge, preventing timely and effective intervention. Diabetes and hypertension are two main causes of kidney disease, can often appear together, and can only be distinguished by invasive biopsy. In this study, we developed a modelling approach to simulate blood velocity, volumetric flow rate, and pressure wave propagation in arterial networks of ageing, diabetic, and hypertensive virtual populations. The model was validated by comparing our predictions for pressure, volumetric flow rate and waveform-derived indexes with in vivo data on ageing populations from the literature. The model simulated the effects of kidney disease, and was calibrated to align quantitatively with in vivo data on diabetic and hypertensive nephropathy from the literature. Our study identified some potential biomarkers extracted from renal blood flow rate and flow pulsatility. For typical patient age groups, resistive index values were 0.69 (SD 0.05) and 0.74 (SD 0.02) in the early and severe stages of diabetic nephropathy, respectively. Similar trends were observed in the same stages of hypertensive nephropathy, with a range from 0.65 (SD 0.07) to 0.73 (SD 0.05), respectively. Mean renal blood flow rate through a single diseased kidney ranged from 329 (SD 40, early) to 317 (SD 38, severe) ml/min in diabetic nephropathy and 443 (SD 54, early) to 388 (SD 47, severe) ml/min in hypertensive nephropathy, showing potential as a biomarker for early diagnosis of kidney disease. This modelling approach demonstrated its potential application in informing biomarker identification and facilitating the setup of clinical trials.

Nephrotic syndrome induced by aortic regurgitation with Takayasu arteritis: an autopsy case with long-term clinical follow-up

Takayasu arteritis is a rare, chronic, and large-vessel vasculitis involving the aorta and its branches in a complex autoimmune reaction. Takayasu arteritis sometimes complicates aortic regurgitation and chronic kidney disease, but rarely accompanies nephrotic syndrome. We had a patient with Takayasu arteritis and concomitant aortic regurgitation. She had nephrotic syndrome that was refractory to immunosuppressive therapy but was promptly improved after surgical aortic valve replacement. In her kidney biopsy, glomeruli had mild mesangial proliferative changes without immune complex deposition. Her proteinuria remained negative until the recurrence of aortic regurgitation due to perivalvular leakage. Seventeen years after the surgery, she died suddenly. In her kidney autopsy, the arteriolar showed severe hyalinosis and the glomerulus showed mesangial proliferative changes with segmental mesangiolysis. Severe aortic regurgitation may have altered renal hemodynamics and caused glomerular lesions, resulting in nephrotic syndrome. We should be aware of the rare but critical comorbidity of nephrotic syndrome in patients with Takayasu arteritis and concomitant aortic regurgitation.

Positive Association of Pulse Pressure with Presence of Albuminuria in Chinese Adults with Prediabetes: A Community-Based Study

Purpose: There has been limited evidence for the association between pulse pressure (PP) and proteinuria in prediabetes. The aim of our study was to explore the association between PP and albuminuria in community-dwelling Chinese adults with prediabetes. Materials and Methods: PP and urinary albumin-to-creatinine ratio (ACR) were measured in 2012 prediabetic patients and 3596 control subjects with normal glucose tolerance. Multivariate logistic regression models were used to evaluate the possible association of PP with the risk of presence of albuminuria. Results: PP was positively associated with the presence of albuminuria, and subjects in the higher PP quartiles had higher urinary ACR and presence of albuminuria as compared with those in the lowest quartile in both prediabetes and control groups (all P < 0.01). Multivariate logistic regression analysis demonstrated that the highest PP quartile was positively associated with increased risk of presence of albuminuria in all prediabetic subjects [odds ratio (OR): 2.289, 95% confidence interval (CI) 1.364-3.842, P < 0.01) and prediabetic subjects without anti-hypertensive drugs (OR: 1.932, 95% CI 1.116-3.343, P < 0.01), whereas higher PP quartile has nothing to do with the risk of presence of albuminuria in control subjects with and without anti-hypertensive drugs after adjustment for potential confounders (all P > 0.01). Consistently, stratified analysis showed that in the prediabetes group, the risks of presence of albuminuria progressively elevated with increasing PP quartiles in men, those aged 60 years or older, and with overweight/obesity, normal high-density lipoprotein cholesterol, and appropriate low-density lipoprotein cholesterol (all P for trend <0.05). Conclusion: Higher PP is independently related to increased risk of presence of albuminuria in community-dwelling Chinese adults with prediabetes.

Higher Arterial Stiffness Predicts Chronic Kidney Disease in Adults: The ELSA-Brasil Cohort Study

BACKGROUND

Central Illustration : Higher Arterial Stiffness Predicts Chronic Kidney Disease in Adults: The ELSA-Brasil Cohort Study.

BACKGROUND

Arterial stiffening can directly affect the kidneys, which are passively perfused by a high flow. However, whether the relation between arterial stiffness and renal function depends on diabetes and hypertension conditions, is a matter of debate.

OBJECTIVE

To investigate the relationship between arterial stiffening by carotid-to-femoral pulse wave velocity (cfPWV) and chronic kidney disease (CKD) incidence in individuals and verify whether this association is present in individuals without hypertension and diabetes.

METHODS

A longitudinal study of 11,647 participants of the ELSA-Brasil followed up for four years (2008/10-2012/14). Baseline cfPWV was grouped per quartile, according to sex-specific cut-offs. Presence of CKD was ascertained by glomerular filtration rate (eGFR-CKD-EPI) < 60 ml/min/1.73 m2 and/or albumin-to-creatinine ratio ≥ 30 mg/g. Logistic regression models were run for the whole cohort and a subsample free from hypertension and diabetes at baseline, after adjustment for age, sex, race, schooling, smoking, cholesterol/HDL ratio, body mass index, diabetes, use of antihypertensive, systolic blood pressure, heart rate, and cardiovascular disease. Statistical significance was set at 5%.

RESULTS

The chance of CKD was 42% (CI 95%: 1.05;1.92) greater among individuals in the upper quartile of cfPWV. Among normotensive, non-diabetic participants, individuals in the 2nd, 3rd, and 4th quartiles of cfPWV presented greater chances of developing CKD, as compared to those in the lower quartile, and the magnitude of this association was the greatest for those in the upper quartile (OR: 1.81 CI 95%: 1.14;2.86).

CONCLUSION

Higher cfPWV increased the chances of CKD and suggests that this effect is even greater in individuals without diabetes and hypertension.

Sleeve gastrectomy and one-year outcomes: Impact on cardiovascular, renal and metabolic parameters

Background

Cardiovascular and renal diseases represent a major determinant for the morbidity and mortality associated with obesity and type 2 diabetes mellitus (T2DM). Bariatric surgery is considered one of the few treatments with the potential to reverse cardiovascular, renal and metabolic disease.

Methods

Prospective study of patients undergoing sleeve gastrectomy collecting pre- and post-surgery creatinine, eGFR, glucose, insulin, total, LDL/HDL cholesterol, triglycerides, parathyroid hormone, vitamin D3, C- Reactive Protein (CRP), blood count, weight, body mass index (BMI), bilateral carotid intima media thickness (IMT), flow-mediated dilation (FMD) and epicardial adipose tissue (EAT). Measurements were compared at 1 year follow up.

Results

24 patients were included in the study. Cardiovascular parameters, as HDL-cholesterol (p = 0.002), IMT (p = 0.003), EAT (p < 0.001) and FMD (p = 0.001) showed significant improvement after surgery. Secondary renal outcomes including Vitamin D3 (p < 0.0001), Calcium (p = 0.006), RBCs (p = 0.007), HCO3- (p = 0.05) also ameliorated as well as BMI (p < 0.001).

Conclusions

Sleeve gastrectomy has a positive impact on cardiovascular, renal, and metabolic parameters in patients with morbid obesity, suggesting it may halt the progression of these diseases even in the preclinical stage. Further research is needed to explore the long-term effects underlying these improvements.

Association of Lower Extremity Muscle Strength and Function with Renal Resistive Index in Individuals with and without Chronic Kidney Disease

Age-related loss of lower extremity muscle strength is pronounced in individuals with chronic kidney disease (CKD). In contrast, an increase in intrarenal flow pulsatility results in initial age-related changes in renal hemodynamics, leading to the development of CKD. To date, it remains unclear whether lower extremity muscle strength determines elevated renal flow pulsatility. This study aimed to determine the association of lower extremity muscle strength and function with intrarenal hemodynamics in individuals with and without CKD. One hundred seventy-six individuals without CKD (aged 63 ± 9 years) and 101 individuals with CKD (aged 66 ± 8 years) were included in this study. Using Doppler ultrasound, the renal resistive index (RI) was measured as a parameter of renal hemodynamics. Knee extensor muscle strength (KES), gait speed (GS), and the 30 s chair stand test (30s-CST) were used to measure lower extremity muscle strength and function. Multivariate analyses showed that GS and 30s-CST scores were independent determinants of renal RI, whereas the KES score was not associated with renal RI in individuals with and without CKD. In the two-way analysis of covariance, renal RI was the highest in individuals with CKD who had lower KES, GS, and 30s-CST scores. Reduced lower extremity muscle strength and function are independent determinants of elevated renal flow pulsatility in individuals with and without CKD.

Being overweight worsens the relationship between urinary sodium excretion and albuminuria: the Wakuya study

BACKGROUND/OBJECTIVES

(Micro)albuminuria (a manifestation of renal microvascular damage) is an independent predictor of mortality risk, even when the urinary albumin/creatinine ratio is ≥ 10 mg/g in the general population. Excessive sodium intake and obesity are strong predictors of cardiovascular disease. However, the effect of obesity on the relationship between sodium intake and albuminuria is not fully understood.

SUBJECTS/METHODS

The purpose of the present study was to investigate the cross-sectional relationships among dietary sodium intake, obesity, and albuminuria in a general population cohort. Subjects were 928 apparently healthy adults. Body mass index was calculated using the height and body weight. Urinary sodium/creatinine and albumin/creatinine ratios were measured in spot urine samples. Estimated 24-h urinary sodium/creatinine ratio (e24UNa/Cr) was assessed using age, height, body weight, and spot urinary sodium/creatinine ratio.

RESULTS

Both the body mass index and e24UNa/Cr positively correlated with the urinary albumin/creatinine ratio (both, P < 0.001), and had a synergistic effect on increasing urinary albumin/creatinine ratio independent of age, sex, mean arterial pressure, and diabetes (interaction P = 0.04). When subjects were divided into 6 groups according to the tertiles of e24UNa/Cr and body mass index < (normal-weight) or ≥ 25 (overweight), the prevalence rate of urinary albumin/creatinine ratio ≥ 10 mg/g increased with rising e24UNa/Cr and being overweight (P < 0.001).

CONCLUSION

An increase in body mass index increases the positive association between urinary sodium excretion and (micro)albuminuria in the general population. Excess sodium intake may strengthen cardiovascular risk by increasing (micro)albuminuria, particularly in overweight individuals.

Research on the correlation between the renal resistive index, renal microvessel density, and fibrosis

BACKGROUND

This study was designed to investigate the relationship between the renal resistive index (RRI), renal microvessel density (RMD), and fibrosis in patients with chronic kidney disease (CKD).

METHODS

A total of 73 CKD patients were included in the study. Prior to kidney biopsy, we recorded the RRI of the interlobar artery and the estimated glomerular filtration rate (eGFR). Immunohistochemical analysis was performed to assess CD34 expression, and Masson staining was used to evaluate histopathological specimens for RMD and the degree of fibrosis. The percentage of the positive area (PPA) was recorded. Subsequently, we investigated the correlation between RRI, RMD, and kidney fibrosis.

RESULTS

RMD (CD34 PPA-total and CD34 PPA-peritubular capillary) showed a slight increase in early CKD stages (1-2) and gradually declined from CKD stages 2 to 5. No correlation was observed between the RRI and RMD or between the RRI and fibrosis across CKD stages 1 to 5. However, across CKD stages 2 to 5, RRI negatively correlated with CD34 PPA-glomerulus (r = -0.353, p = 0.022), but no correlation was found with CD34 PPA-total, CD34 PPA-peritubular capillary, or kidney fibrosis. eGFR showed a positive correlation with RMD (CD34 PPA-total, CD34 PPA-peritubular capillary, and CD34 PPA-glomerulus) across CKD stages 2 to 5, while no correlation was found from CKD stages 1 to 5.

CONCLUSION

There was no correlation between RRI and RMD or between RRI and fibrosis across CKD stages 1 to 5 (RRI ≤ 0.7).

Brachial-ankle pulse wave velocity is associated with intracranial artery calcification in acute stroke patients

BACKGROUND

Intracranial artery calcification (IAC) is closely associated with cerebrovascular disease. Brachial-ankle pulse wave velocity (baPWV) is a noninvasive method for estimating arterial stiffness, which reflects the stiffness of peripheral arteries. This study aimed to examine the association of baPWV with the presence and degree of IAC in patients with acute ischemic stroke.

METHODS

A total of 143 ischemic stroke subjects were recruited. A head computed tomography (CT) scan was used to assess the presence and severity of IAC. The oscillometric method was used to simultaneously measure bilateral brachial and posterior tibial arterial pulse waveforms and arterial BP. Multiple logistic regression analysis was used to identify the independent relationship between baPWV and IAC.

RESULTS

143 subjects were included in this study. The demographic and clinical characteristics of the study population were classified according to the baPWV quartile. A higher prevalence of IAC was noted across increasing baPWV quartiles (Q1: 53 %, Q2: 69 %, Q3: 86 %, Q4: 94 %, P < 0.001). IAC scores were also increased with elevated ccPWV values (1.60 ± 1.71; 2.56 ± 1.99; 3.44 ± 1.91; 4.64 ± 1.58. P < 0.001). After an additional adjustment for age and hypertension, the odds ratio (95 % confidence interval) for the IAC scores was 1.61 (1.06-2.45; P = 0.025) in the top quartile of baPWV compared with those in the lowest quartile.

CONCLUSIONS

Arterial stiffness as defined by baPWV was positively associated with the degree of IAC in patients with acute ischemic stroke, suggesting the severity of IAC may also be a marker of peripheral or systemic arterial stiffness.

Excess adiposity contributes to higher ambulatory central blood pressure and arterial stiffness in physically inactive young adults

BACKGROUND

It remains unknown if physical inactivity and excess adiposity increases 24-h central blood pressure and arterial stiffness in young adults. This study examined 24-h central blood pressure and indirect measures of arterial stiffness (e.g., central pulse pressure) in physically inactive young adults with and without excess adiposity.

METHODS

Body fat and ambulatory 24-h blood pressure were measured in 31 young adults (men: 22±4 years, N.=15; women: 22±5 years, N=16). Multi-frequency bioelectrical impedance measured body fat. Normal adiposity was defined as <20% body fat in men and <32% body fat in women, whereas excess adiposity was defined as ≥20% and ≥32% in men and women, respectively. Ambulatory 24-h central blood pressure was calculated based on brachial blood pressure and volumetric displacement waveforms.

RESULTS

By design, the normal adiposity group had a lower body fat percentage (men: 15.5±4.6%; women: 20.8±2.5%) compared to the physically inactive excess adiposity group (men: 29.8±5.4%; women: 34.3±7.5%). Men and women with excess adiposity group had elevated central blood pressure (central systolic, P<0.05 vs. normal adiposity groups). Central pulse pressure was elevated in the excess adiposity group (men: 45±5 mmHg; women: 41±9 mmHg) compared to normal adiposity groups (men: 36±4 mmHg; women: 32±3 mmHg, P<0.05 for both), while other arterial stiffness (augmentation index and ambulatory arterial stiffness index) measures trended toward significance only in men with excess adiposity.

CONCLUSIONS

Physically inactive men and women with excess adiposity have increased 24h central blood pressure and pulse pressure compared to physically inactive young adults with normal adiposity.

Elevated urinary angiotensinogen excretion links central and renal hemodynamic alterations

Inappropriate activation of intrarenal renin-angiotensin system (RAS) may contribute to the pathogenesis of cardio-renal syndrome (CRS). We aimed to examine the cross-sectional associations of urinary angiotensinogen (AGT) excretion, a biomarker of intrarenal RAS activity, with central (aortic) and renal hemodynamic parameters in middle-aged and older adults, including patients with chronic kidney disease. Aortic and renal hemodynamic parameters were measured using applanation tonometry and duplex ultrasonography in 282 participants. Urinary AGT, liver-type fatty acid-binding protein (L-FABP), and plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were measured for each participant. Multiple linear regression analyses demonstrated that urinary AGT levels were associated with aortic blood pressures, pulsatile measures of renal blood flow, plasma NT-proBNP and urinary L-FABP levels after adjusting for potential covariates, including age, sex, body mass index, estimated glomerular filtration rate (GFR), and medication use. Additionally, when classified based on GFR stages and urinary AGT levels, plasma NT-proBNP and urinary L-FABP levels increased in participants with lower GFR and higher AGT groups. Our findings suggest that urinary AGT excretion is a shared determinant of central (aortic) and renal hemodynamics in middle-aged and older adults, providing clinical evidence for the potential role of intrarenal RAS activity in the development of CRS.

The renal resistive index is associated with microvascular remodeling in patients with severe obesity

BACKGROUND

Renal hemodynamics is impaired since the early stage of cardiometabolic disease. However, in obesity, its noninvasive ultrasound assessment still fails to provide pathophysiologic and clinical meaningfulness. We aimed to explore the relationship between peripheral microcirculation and renal hemodynamics in severe obesity.

METHODS

We enrolled fifty severely obese patients with an indication for bariatric referring to our outpatient clinic. Patients underwent an extensive reno-metabolic examination, paired with Doppler ultrasound and measurement of the renal resistive index (RRI). On the day of the surgery, visceral fat biopsies were collected to perform an ex-vivo complete microcirculatory assessment. Media-to-lumen ratio (M/L) and vascular response to acetylcholine (ACh), alone or co-incubated with N G -nitro arginine methyl ester (L-NAME), were measured.

RESULTS

Patients were stratified according to their normotensive (NT) or hypertensive (HT) status. HT had lower estimated glomerular filtration rate and higher RRI compared to NT, while the presence and extent of albuminuria were similar between the two groups. Concerning microcirculatory assessment, there were no differences between groups as regards the microvascular structure, while the vasorelaxation to ACh was lower in HT ( P = 0.042). Multivariable analysis showed a relationship between M/L and RRI ( P  = 0.016, St. β 0.37) and between albuminuria and the inhibitory response of L-NAME to Ach vasodilation ( P   =  0.036, St. β = -0.34). Notably, all these correlations were consistent also after adjustment for confounding factors.

CONCLUSIONS

The RRI and albuminuria relationship with microvascular remodeling in patients affected by severe obesity supports the clinical implementation of RRI to improve risk stratification in obesity and suggests a tight pathophysiologic connection between renal haemodynamics and microcirculatory disruption.

Effect of night shift work on the reduction of glomerular filtration rate using data from Korea Medical Institute (2016-2020)

Background

Shift work increases the risk of chronic diseases, including metabolic diseases. However, studies on the relationship between shift work and renal function are limited. The aim of this study was to investigate the association between shift work and a decreased glomerular filtration rate (GFR).

Methods

Data were evaluated for 1,324,930 workers who visited the Korean Medical Institute from January 1, 2016 to December 31, 2020 and underwent a health checkup. Daytime workers were randomly extracted at a ratio of 1:4 after matching for age and sex. In total, 18,190 workers aged over 40 years were included in the analyses; these included 3,638 shift workers and 14,552 daytime workers. Participants were categorized into the shift work group when they underwent a specific health checkup for night shift work or indicated that they were shift workers in the questionnaire. The odds ratio was calculated using a conditional logistic regression to investigate the relevance of shift work for changes in GFR.

Results

35 workers in the shift group and 54 in the daytime group exhibited an estimated GFR (eGFR) value of < 60 mL/min/1.73m2 (p < 0.01). The difference in eGFR values between two checkups differed significantly depending on the type of work (p < 0.01); the difference in the shift work group (-9.64 mL/min/1.73 m2) was larger than that in the daytime work group (-7.45 mL/min/1.73 m2). The odds ratio for eGFR reduction to < 60 mL/min/1.73 m2 in the shift group versus the daytime group was 4.07 (95% confidence interval: 2.54-6.52), which was statistically significant.

Conclusions

The results of this study suggest that eGFR decreases by a significantly larger value in shift workers than in daytime workers; thus, shift work could be a contributing factor for chronic kidney disease (CKD). Further prospective studies are necessary to validate this finding and identify measures to prevent CKD in shift workers.

Current Insights into the Significance of the Renal Resistive Index in Kidney and Cardiovascular Disease

Initially, the renal resistive index (RRI) was investigated with the aim of improving diagnosis in kidney diseases, but this goal was not met. Recently, many papers have highlighted the prognostic significance of the RRI in chronic kidney disease: specifically, in estimating the revascularization success of renal artery stenoses or the evolution of the graft and the recipients in renal transplantation. Moreover, the RRI has become significant in the prediction of acute kidney injury in critically ill patients. Studies in renal pathology have revealed correlations of this index with parameters of systemic circulation. The theoretical and experimental premises of this connection were then reconsidered, and studies analyzing the link between RRI and arterial stiffness, central and peripheral pressure, and left ventricular flow were conducted with this purpose. Many data currently indicate that RRI is influenced more by pulse pressure and vascular compliance than by renal vascular resistance-assuming that RRI reflects the complex interplay between systemic circulation and renal microcirculation and should be considered a marker of systemic cardiovascular risk beyond its prognostic relevance for kidney disease. In this review, we overview the clinical research that reveals the implications of RRI in renal and cardiovascular disease.

Association between trunk flexibility and renal flow pulsatility in middle-aged and older adults

BACKGROUND

Recent clinical studies have indicated that poor trunk flexibility is associated with arterial stiffness in the aged. Arterial stiffness leads to elevated renal flow pulsatility, which accelerates age-related renal dysfunction and damages. However, data indicating the potential link between flexibility fitness and renal flow pulsatility are lacking. This study examined the cross-sectional association between trunk flexibility and renal flow pulsatility in middle-aged and older adults.

METHODS

A total of 175 middle-aged and older adults (aged 63 ± 9 years) were included in this study. Sit-and-reach tests (SRT) were performed to assess their trunk flexibility. Using a Doppler ultrasound, renal pulsatility index (PI) and resistive index (RI) were measured as parameters of renal flow pulsatility.

RESULTS

The study found that, in middle-aged and older adults, the SRT score was an independent determinant of renal PI (β = -0.134, P = 0.027) and RI (β = -0.135, P = 0.027). In the one-way analysis of covariance (ANCOVA), the renal PI and RI in the older group with a lower SRT score were found to be significantly higher than those in the middle-aged group.

CONCLUSIONS

Trunk flexibility is an independent determinant of renal flow pulsatility in middle-aged and older adults.

Association Between Arterial Stiffness and New-Onset Heart Failure: The Kailuan Study

BACKGROUND

Arterial stiffness (AS) was associated with heart failure (HF) in previous studies based on specific populations with small samples and the effects of age and blood pressure on AS were not taken into account. Whether AS was independently associated with new-onset HF in community dwellers has not been fully investigated to date.

METHODS

Individuals who participated in health evaluations and underwent synchronized brachial-ankle pulse wave velocity (baPWV) screening in 2010 to 2019 were included. They were free of HF and atrial fibrillation at baseline. The participants were allocated to 3 groups according to their baPWV values. Normal AS was defined as baPWV <1400 cm/s, borderline AS was defined as 1400≤baPWV<1800 cm/s, and elevated AS was defined as baPWV ≥1800 cm/s. Cox proportional hazard regression was used to calculate hazard ratios with 95% CIs of new-onset HF across different AS groups.

RESULTS

A total of 40 064 participants were enrolled with a mean age of 48.81±12.67 years. During a mean 5.53 years of follow-up, 411 participants developed HF. Compared with the normal AS group, the hazard ratio (95% CI) for incident HF was 1.97 (1.36-2.86) for the borderline AS group and 2.24 (1.49-3.38) for the elevated AS group in the multivariable-adjusted model. For each 1 SD (359 cm/s) increase in baPWV, the hazard ratio (95% CI) for new-onset HF was 1.10 (1.02-1.20).

CONCLUSIONS

AS was positively associated with a higher risk of new-onset HF independently of traditional risk factors, with a dose-responsive effect.

Calcification of the visceral aorta and celiac trunk is associated with renal and allograft outcomes after deceased donor liver transplantation

PURPOSE

Atherosclerosis affects clinical outcomes in the setting of major surgery. Here we aimed to investigate the prognostic role of visceral aortic (VAC), extended visceral aortic (VAC+), and celiac artery calcification (CAC) in the assessment of short- and long-term outcomes following deceased donor orthotopic liver transplantation (OLT) in a western European cohort.

METHODS

We retrospectively analyzed the data of 281 consecutive recipients who underwent OLT at a German university medical center (05/2010-03/2020). The parameters VAC, VAC+, or CAC were evaluated by preoperative computed tomography-based calcium quantification according to the Agatston score.

RESULTS

Significant VAC or CAC were associated with impaired postoperative renal function (p = 0.0016; p = 0.0211). Patients with VAC suffered more frequently from early allograft dysfunction (EAD) (38 vs 26%, p = 0.031), while CAC was associated with higher estimated procedural costs (p = 0.049). In the multivariate logistic regression analysis, VAC was identified as an independent predictor of EAD (2.387 OR, 1.290-4.418 CI, p = 0.006). Concerning long-term graft and patient survival, no significant difference was found, even though patients with calcification showed a tendency towards lower 5-year survival compared to those without (VAC: 65 vs 73%, p = 0.217; CAC: 52 vs 72%, p = 0.105). VAC+ failed to provide an additional prognostic value compared to VAC.

CONCLUSION

This is the first clinical report to show the prognostic role of VAC/CAC in the setting of deceased donor OLT with a particular value in the perioperative phase. Further studies are warranted to validate these findings. CT computed tomography, OLT orthotopic liver transplantation.

Measurement of Serum N-Glycans in the Assessment of Early Vascular Aging (Arterial Stiffness) in Adults With Type 1 Diabetes

OBJECTIVE

Vascular aging (arterial stiffness [AS]) is an inflammation-linked process that predicts macro- and microvascular complications in adults with type 1 diabetes (T1D). We evaluated the utility of measuring the inflammation-linked N-glycans GlycA and GlycB to assess vascular aging in adults with T1D.

RESEARCH DESIGN AND METHODS

Eighty-four adults with T1D (>10-year duration without cardiovascular events) and 68 healthy control subjects were evaluated for clinical characteristics (including microvascular complications in patients with T1D), aortic pulse wave velocity (aPWV) (surrogate measure of AS), and serum GlycA and GlycB (peak area [concentration] and height/width [H/W] ratio) using 1H-nuclear magnetic resonance spectroscopy.

RESULTS

Patients with T1D had higher median (interquartile range) values than healthy control subjects for (P < 0.001 for all comparisons) aPWV 7.9 (6.9-9.1) vs. 6.1 (5.5-6.7) m/s, GlycA 850.4 (781.3-916.1) vs. 652.4 (581.5-727.1) μmoL; GlycB 386.1 (353.2-426.3) vs. 310.0 (280.5-331.9) μmol/L), H/W ratio of GlycA 16.5 (14.9-18.1) vs. 15.0 (13.7-16.7), and H/W ratio of GlycB 5.0 (4.6-5.5) vs. 4.0 (3.4-4.3). Moreover, aPWV correlated (P < 0.001 for all correlations) with GlycA (r = 0.550) and GlycB (r = 0.423) concentrations and with H/W ratios of GlycA (r = 0.453) and GlycB (r = 0.510). Adjusting for potential confounders, GlycA concentration (β = 0.212, P < 0.001) and the H/W ratios of GlycA (β = 0.150, P = 0.009) and GlycB (β = 0.155, P = 0.011) remained independently associated with aPWV. C-statistics for detecting individuals with aPWV >10 m/s were 0.866 (95% CI 0.794-0.937) for GlycA levels and 0.862 (0.780-0.943) for H/W ratio of GlycB.

CONCLUSIONS

Measurement of serum GlycA and GlycB may have utility in assessing vascular aging in adults with T1D of >10-year duration and no previous cardiovascular events.

Cerebral and renal hemodynamics: similarities, differences, and associations with chronic kidney disease and aortic hemodynamics

Elevated arterial pulsatility is a common risk factor for cerebrovascular disease and chronic kidney disease (CKD), which suggests that the brain and kidneys may have similar hemodynamic profiles. The objectives of this study were twofold: 1) to compare and contrast the cerebral and renal blood flow parameters in adults without CKD (hereafter, non-CKD adults) and CKD patients and 2) to determine the common predictor(s) of cerebral and renal hemodynamics among pressure pulsatility and several cardiovascular risk factors. In 110 non-CKD adults and 66 CKD patients, cerebral and renal blood flow velocity (BFV) were measured by transcranial Doppler and Duplex ultrasonography, respectively. Pulsatile hemodynamics were assessed by the pulsatility (PI) and resistive (RI) indices. Aortic pulse pressure was measured by tonometry. Compared with non-CKD adults, CKD patients showed greater pulsatility of the BFV (i.e., systolic minus diastolic BFV), PI, and RI in the kidneys but not the brain. However, the cerebral and renal PI and RI values were strongly correlated in both non-CKD adults (both PI and RI values: r_s = 0.695) and CKD patients (both PI and RI values: r_s = 0.640) (all P < 0.001). Multiple linear regression analysis further demonstrated that the cerebral and renal PI and RI associations remained significant after adjustment for potential covariates (e.g., age, sex, the presence of CKD). The aortic pulse pressure was a significant predictor for both cerebral and renal PI and RI values. Collectively, our findings suggest that CKD patients have higher renal flow pulsatility, which is strongly and independently associated with cerebral flow pulsatility and aortic hemodynamics.

Aortic stiffness and aortic-brachial stiffness mismatch as markers of renal dysfunction in hypertension

PURPOSE

The dismal combination of hypertension and chronic kidney disease potentiates both cardiovascular disease and loss of renal function. Research points to the importance of arterial and left ventricular stiffening in this process but few studies have compared aspects of central and peripheral hemodynamics in relation to renal function in hypertension.

MATERIALS AND METHODS

We investigated 107 hypertensive individuals with renal function ranging from normal to severe dysfunction with pulse wave analysis to obtain central blood pressures (BP), augmentation index, carotid-femoral and carotid-radial pulse wave velocity (cfPWV, crPWV), aortic-to-brachial stiffness mismatch (cfPWV/crPWV), endothelial function by forearm flow-mediated vasodilation and myocardial microvascular function by subendocardial viability ratio, and indices of left ventricular structure (left ventricular mass index and relative wall thickness, RWT) and diastolic function (left atrial volume index, E/A, and E/é).

RESULTS

Mean age was 58 years, BP 149/87 mm Hg, 9% had cardiovascular disease, and 31% were on antihypertensive treatment. Mean estimated glomerular filtration rate (eGFR) was 74 (range 130-21) ml/min × 1.73 m². Whereas cfPWV and cfPWV/crPWV were independently related to eGFR (r = -0.20, p = 0.002, r = -0.16, p = 0.01), central diastolic BP (r = 0.21, p = 0.04), RWT (r = -0.34, p = 0.001), E/é (r = -0.39, p < 0.001) and E/A (r = 0.27, p = 0.01) were related to eGFR in bivariate correlations, but these findings were not retained in multivariate analyses. Remaining markers of hypertensive heart disease and measures of microvascular function were not related to eGFR.

CONCLUSION

Increased aortic stiffness and aortic-to-brachial stiffness mismatch are independently related to reduced eGFR in hypertensive patients, suggesting an important role for aortic stiffness in the evolution of hypertension-mediated renal dysfunction. Aortic stiffness and aortic-brachial stiffness mismatch may be useful early markers to find hypertensive patients at risk for decline in renal function.

Skin microvascular function, as assessed with laser speckle contrast imaging, is impaired in untreated essential and masked hypertension

Skin microcirculation has been proposed as a model of generalized microvascular function. Laser speckle contrast imaging (LSCI) is a novel, noninvasive method to assess skin microvascular function (SMF). To date, SMF data in hypertension are conflicting, and no study with LSCI exists. In addition, the application of LSCI in masked hypertension is scarce. We assessed SMF with LSCI coupled with postocclusive reactive hyperemia (PORH) in patients with newly diagnosed untreated essential hypertension (UHT) and masked hypertension (MH) compared to healthy normotensive (NT) individuals. We enrolled consecutive UHT and MH patients and NT individuals matched for age, sex, body mass index, and smoking status. All participants underwent SMF assessment by LSCI coupled with PORH (PeriCam PSI system, Perimed, Sweden). Correlation analyses were performed between SMF and common cardiovascular risk factors and BP parameters. In total, 70 UHT patients, 20 MH patients and 40 NT individuals were enrolled. UHT and MH patients exhibited significantly impaired SMF compared to NT individuals (UHT patients: base-to-peak flux (p < 0.001)), PORH amplitude (p < 0.001); MH patients: base-to-peak flux (p = 0.013), PORH amplitude (p = 0.022). MH patients did not differ compared to UHT patients. SMF was negatively associated with office, ambulatory and central BP. SMF was negatively associated with blood lipids and smoking. Hypertensive status was the single most important predictor of SMF. UHT and MH patients exhibit impaired SMF compared to NT individuals. MH patients did not differ compared to UHT patients. SMF is negatively associated with BP and cardiovascular risk factors. LSCI could be implemented as a useful tool to investigate SMF in hypertension.

Kidney hemodynamic profile and systemic vascular function in adults with type 2 diabetes: Analysis of three clinical trials

AIMS

Glomerular hyperfiltration plays a key role in the pathophysiology of diabetic kidney disease (DKD). Mechanisms underlying this adverse hemodynamic profile are incompletely understood. We hypothesized that systemic vascular pathology, including endothelial dysfunction and arterial stiffness, relates to glomerular hyperfiltration indicated by filtration fraction (FF).

METHODS

Baseline data of three trials of overweight adults with type 2 diabetes (TD2, n = 111) with relatively well preserved kidney function were analyzed. Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and FF, were assessed with gold-standard clearance techniques. Systemic vascular resistance (SVR), an indicator of endothelial dysfunction, and pulse pressure (PP), a measure of arterial stiffness, were derived from continuous beat-to-beat monitoring.

RESULTS

SVR related negatively to GFR (β: -0.382, p < 0.001) and ERPF (β: -0.475, p < 0.001), and positively to FF (β:0.369, p < 0.001). Associations between SVR, ERPF and FF persisted after multivariable adjustments.. PP was negatively related to ERPF (β: -0.252, p = 0.008), and positively to FF (β: 0.257, p = 0.006), of which the latter remained significant in multivariable regression.

CONCLUSION

Parameters of systemic vascular pathology, including endothelial dysfunction and arterial stiffness, relate to an adverse kidney hemodynamic profile characterized by glomerular hyperfiltration, which predisposes to the development of DKD.

Central-to-peripheral stiffness gradients determine diastolic pressure and flow fluctuation waveforms: time domain analysis of femoral artery pulse

OBJECTIVE

Blood pressure fluctuates during diastole to create a dicrotic wave but the mechanistic origin remains poorly understood. We sought to investigate the characteristics and determinants of diastolic pressure and flow fluctuations with a focus on stiffness gradients between the central aorta and peripheral arteries.

METHODS

Using applanation tonometry and duplex ultrasound, pulse waveforms were recorded on the femoral artery in 592 patients (age: 55 ± 14 years) to estimate the diastolic pressure fluctuation as a residual wave against the mono-exponential decay and the diastolic flow fluctuation as a bidirectional (forward and reverse) velocity wave. The radial, carotid, and dorsalis pedis pressures were also recorded to measure the peripheral/aortic pulse pressure (PP) and pulse wave velocity (PWV) ratios.

RESULTS

There were close resemblances between the femoral pressure and flow fluctuation waveforms. The pressure and flow fluctuations were mutually correlated in relative amplitude as indexed to the total pulse height (r = 0.63), and the former temporally followed the latter. In multivariate-adjusted models, higher peripheral/aortic PP and PWV ratios were independently associated with greater pressure and flow fluctuation indices (P < 0.001). Mediation analysis revealed that the associations of PP and PWV ratios with the pressure fluctuation index were largely mediated by the flow fluctuation index [indirect/total effect ratio: 57 (95% CI 42-80)% and 54 (30-100)%, respectively].

CONCLUSION

These results suggest that central-to-peripheral pulse amplification and stiffness gradients contribute to triphasic flow fluctuations and dicrotic pressure waves. Diminished or inverted stiffness gradients caused by aortic stiffening may thus reduce diastolic runoff leading to ischemic organ damage.

Ιmmunity, Vascular Aging, and Stroke

Stroke is one of the most devastating manifestations of cardiovascular disease. Growing age, arterial hypertension, and atherosclerosis are identified as independent risk factors for stroke, primarily due to structural and functional alterations in the cerebrovascular tree. Recent data from in vitro and clinical studies have suggested that the immune system influences atherosclerosis, promoting vascular stiffness and vascular aging and contributing to ischemic stroke, intracranial haemorrhage and microbleeds, white matter disease, and cognitive decline. Furthermore, aging is related to a chronic low-grade inflammatory state, in which macrophage, neutrophils, natural killer (NK cells), and B and T lymphocytes act as major effectors of the immune-mediated cell responses. Moreover, oxidative stress and vascular inflammation are correlated with endothelial dysfunction, vascular aging, blood-brain barrier disruption, lacunar lesions, and neurodegenerative disorders. This review discusses the pathophysiological roles of fundamental cellular and molecular mechanisms of aging, including the complex interplay between them and innate immunity, as well as vascular dysfunction, arterial stiffness, atherosclerosis, atherothrombosis, systemic inflammation, and blood-brain barrier dysfunction.

The Mechanobiology of Vascular Remodeling in the Aging Lung

Aging is accompanied by declining lung function and increasing susceptibility to lung diseases. The role of endothelial dysfunction and vascular remodeling in these changes is supported by growing evidence, but underlying mechanisms remain elusive. In this review we summarize functional, structural, and molecular changes in the aging pulmonary vasculature and explore how interacting aging and mechanobiological cues may drive progressive vascular remodeling in the lungs.

Comparison of the Association Between Arterial Stiffness Indices and Heart Failure in Patients With High Cardiovascular Risk: A Retrospective Study

Objective: Study findings of the relationship of each arterial stiffness index with incident heart failure (HF) are conflicting. We aimed to compare the association between the indices of arterial stiffness and the risk of HF. Methods: We analysed 3,034 patients from a prospective cohort that enrolled patients with high cardiovascular risk. They underwent brachial-ankle pulse wave velocity (baPWV), brachial pulse pressure (PP), carotid-femoral pulse wave velocity (cfPWV), and central PP measurements. Results: Over a median follow-up of 4.7 years (interquartile range, 3.4-5.8 years), 65 HF events occurred. The incidence rate of HF was 4.7 per 1,000 person-years [95% confidence interval (CI), 3.7-6.0]. There was no difference in baPWV in those with and without HF events (1,561 ± 401 and 1,520 ± 321 cm/s, respectively, P = 0.415); however, there was a significant difference in brachial PP (63.2 ± 16.9 vs. 52.3 ± 11.5 mmHg, P < 0.001), cfPWV (11.0 ± 3.1 vs. 9.4 ± 2.4 m/s, P < 0.001) and central PP (56.6 ± 19.9 vs. 42.9 ± 13.8 mmHg, P < 0.001). In the multivariable-adjusted model, brachial PP [hazards ratio (HR) per standard deviation unit (SDU), 1.48; 95% CI, 1.19-1.84, P < 0.001], cfPWV (HR per SDU, 1.29; 95% CI, 1.02-1.63, P = 0.032) and central PP (HR per SDU, 1.44; 95% CI, 1.17-1.78; P < 0.001) were associated with incident HF, but baPWV was not (HR per SDU, 0.83; 95% CI, 0.63-1.10; P = 0.198). In the receiver operating characteristic analysis, the area under the curve (AUC) of brachial PP (P < 0.001), cfPWV (P = 0.003) or central PP (P = 0.001) was larger than that of baPWV, and there was no difference in the AUCs of brachial PP, cfPWV and central PP. Conclusion: Among arterial stiffness indices, brachial PWV was less associated with the risk of heart failure, and brachial PP and measures representing central hemodynamics were highly associated with incident HF.

Predictors and impact of low diastolic blood pressure and widened pulse pressure following transcatheter aortic valve replacement

BACKGROUND

The association between post-operative diastolic blood pressure (DBP) and pulse pressure (PP) with outcomes following transcatheter aortic valve replacement (TAVR) remains unclear. We sought to assess the prevalence, predictors, and impact of post-operative DBP and PP on presence of post-procedural aortic insufficiency (AI) and mortality in adults undergoing TAVR.

METHODS

The study population included 194 patients who underwent TAVR from 2016 to 2017 at an academic tertiary medical center, of which 176 had invasive arterial pressures available postoperatively. Low DBP and widened PP were defined as ≤40 mmHg and ≥80 mmHg respectively on invasive arterial line on post-operative day 1. Clinical outcomes of interest included post-procedural AI and 1-year all-cause mortality.

RESULTS

Post-operative low DBP and widened PP were noted in 32.4% and 58.5% of the study population. No significant association between post-operative AI and low DBP (p = 0.82) or widened PP (p = 0.32) was noted. There was a trend toward higher rates of mortality in patients with low DBP (19.3% vs 9.2%, p = 0.06) but no difference in mortality in patients with widened PP (10.7% vs 15.1%, p = 0.39) or those with ≥1+ post-procedural AI (16.7% vs 10.7%, p = 0.32). In multivariable analysis, low DBP was associated with a trend toward higher rates of 1-year mortality [odds ratio (OR) 2.43, 95% confidence interval (CI) 0.97-6.11, p = 0.06]. When excluding patients with a post-operative invasive systolic blood pressure < 80 mmHg, low DBP was associated with significantly higher risk-adjusted mortality at 1 year [OR 2.75, 95% CI (1.07-7.07), p = 0.04].

CONCLUSIONS

In this contemporary study of adults undergoing TAVR, low DBP and widened PP were widely prevalent post TAVR. Low DBP was associated with a trend toward higher rates of 1-year mortality but not with post-procedural AI.

Acute kidney injury and aging

Our aging population is growing and developing treatments for age-related diseases such as Alzheimer's and Parkinson's disease has taken on an increasing urgency and is accompanied by high public awareness. The already high and rising incidence of acute kidney injury (AKI) in the elderly, however, has received relatively little attention despite the potentially fatal outcomes associated with an episode of AKI in this age group. When discussing AKI and aging, one should consider two aspects: first, elderly patients have an increased susceptibility to an AKI episode, and second, they have decreased kidney repair after AKI given the high incidence of progression to chronic kidney disease (CKD). It is unclear if the same factors that drive the increased susceptibility to AKI could be playing a role in the decreased repair capacity or if they are totally different and unrelated. This review will examine current knowledge on the risk factors for the increased susceptibility to AKI in the elderly and will also explore potential aspects that might contribute to a decreased kidney repair response in this age group.

Association of Arterial Stiffness With Chronic Kidney Disease Progression and Mortality

Chronic kidney disease (CKD) is a major public health concern. Despite many potentially life-threatening conditions that can accompany kidney disease, cardiovascular disease (CVD) remains the leading cause of death in these patients. Adjusted-for-age mortality from CVD in patients with end-stage renal disease is 10-30 times higher than in the general population. A decrease in renal function accelerates the development of cardiac pathology. Simultaneous exposure of CVD and CKD plays an important role in the relationship between arterial stiffness (AS) and estimated glomerular filtration rate. But there is a controversy as to whether the AS causes deterioration in kidney function, if renal dysfunction leads to AS, or the relationship is reciprocal. Hence, several studies that recruited high-risk populations reached a conclusion that comorbidities might lead to both AS and decline in kidney function over time. A number of studies have shown that several markers of AS, such as pulse pressure, central and peripheral pressure are associated with the development of CKD. This review takes into account the theoretical background, current status, and future potential of the techniques that measure AS within context of CKD assessment and management.

Structural changes in renal arterioles are closely associated with central hemodynamic parameters in patients with renal disease

Although central hemodynamics are known to be closely associated with microvascular damage, their association with lesions in the small renal arteries has not yet been fully clarified. We focused on arterioles in renal biopsy specimens and analyzed whether their structural changes were associated with noninvasive vascular function parameters, including central blood pressure (BP) and brachial-ankle pulse wave velocity (baPWV). Forty-four nondiabetic patients (18-50 years of age) with preserved renal function underwent renal biopsy. Wall thickening of arterioles was analyzed based on the media/diameter ratio, and hyalinosis was analyzed by semiquantitative grading. Associations of these indexes (arteriolar wall remodeling grade index (RG index) and arteriolar hyalinosis index (Hyl index)) with clinical variables were analyzed. Multiple regression analyses demonstrated that the RG index was significantly associated with central systolic BP (β = 0.97, p = 0.009), serum cystatin C-based estimated glomerular filtration rate (β = -0.36, p = 0.04), and high-density lipoprotein cholesterol levels (β = -0.37, p = 0.02). The Hyl index was significantly associated with baPWV (β = 0.75, p = 0.01). Our results indicate that aortic stiffness and abnormal central hemodynamics are closely associated with renal microvascular damage in young to middle-aged, nondiabetic kidney disease patients with preserved renal function.

Albuminuria Intensifies the Link Between Urinary Sodium Excretion and Central Pulse Pressure in the General Population: The Wakuya Study

BACKGROUND

Central pulse pressure (cPP) is responsible for the hemodynamics of vital organs, and monitoring this parameter is important for cardiovascular disease (CVD) prevention. Excess sodium intake and (micro)albuminuria (a manifestation of renal microvascular damage) are known to be strong predictors of CVD. We sought to investigate the cross-sectional relationships among dietary sodium intake, albuminuria, and cPP in a general population cohort.

METHODS

The subjects were 933 apparently healthy adults (mean age, 56 ± 10 years). Radial pressure waveforms were recorded with applanation tonometry to estimate mean arterial pressure (MAP), cPP, forward and backward pressure amplitudes, and augmentation index. The urinary sodium/creatinine and albumin/creatinine ratios were measured in spot urine samples.

RESULTS

Both the urinary sodium/creatinine and albumin/creatinine ratios were positively correlated with cPP, even after adjusting for MAP (P < 0.001). Moreover, both ratios had a synergistic influence on increasing the cPP independent of age, sex, estimated glomerular filtration rate, hyperlipidemia, and diabetes (interaction P = 0.04). A similar synergistic influence was found on the forward pressure amplitude, but not on the backward pressure amplitude or augmentation index. The overall results were not altered when the urinary albumin/creatinine ratio was replaced with the existence of chronic kidney disease (CKD).

CONCLUSIONS

(Micro)albuminuria strengthens the positive association between urinary sodium excretion and cPP and systolic forward pressure. Excess sodium intake may magnify the cardiovascular risk by widening the aortic pulsatile pressure, particularly in the presence of concomitant CKD.

Role of Matrix Gla Protein in the Complex Network of Coronary Artery Disease: A Comprehensive Review

Coronary artery disease (CAD) is widely recognized as one of the most important clinical entities. In recent years, a large body of accumulated data suggest that coronary artery calcification, a process highly prevalent in patients with CAD, occurs via well-organized biologic processes, rather than passively, as previously regarded. Matrix Gla protein (MGP), a vitamin K-dependent protein, emerged as an important inhibitor of both intimal and medial vascular calcification. The functionality of MGP hinges on two post-translational modifications: phosphorylation and carboxylation. Depending on the above-noted modifications, various species of MGP may exist in circulation, each with their respective level of functionality. Emerging data suggest that dysfunctional species of MGP, markedly, dephosphorylated-uncarboxylated MGP, might find its application as biomarkers of microvascular health, and assist in clinical decision making with regard to initiation of vitamin K supplementation. Hence, in this review we summarized the current knowledge with respect to the role of MGP in the complex network of vascular calcification with concurrent inferences to CAD. In addition, we discussed the effects of warfarin use on MGP functionality, with concomitant implications to coronary plaque stability.

Renal hemodynamics across the adult lifespan: Relevance of flow pulsatility to chronic kidney disease

BACKGROUND

Elevated renal flow pulsatility may contribute to the pathogenesis of chronic kidney disease (CKD). The purpose of this study was to investigate the associations among age, renal flow pulsatility, and CKD biomarkers in non-CKD adults and CKD patients.

METHODS

Non-CKD adults (n = 415) and CKD patients (n = 136) aged between 22 and 83 years underwent the renal blood flow measurement using duplex ultrasonography. Pulsatility index (PI) and resistive index (RI) were calculated to assess renal flow pulsatility. The CKD biomarkers such as urinary liver-type fatty acid-binding protein (L-FABP) and serum fibroblast growth factor 23 (FGF23) were measured from each participant. Aortic hemodynamic parameters were measured by applanation tonometry.

RESULTS

In non-CKD adults, advancing age was associated with elevations of renal PI and RI which slowly increased during middle-aged (PI: β = 0.14, RI: β = 0.17) and accelerated in older adults (PI: β = 0.34, RI: β = 0.33). In CKD patients, age-related increases in renal PI and RI were observed only in the middle age group (PI: β = 0.23, RI: β = 0.26). Multivariate analysis demonstrated that renal PI and RI were independently associated with CKD biomarkers, including urinary L-FABP and serum FGF23, and aortic pulse pressure.

CONCLUSIONS

Advancing age is associated with a progressive elevation of renal flow pulsatility which manifests during middle age and accelerates in later life. Moreover, elevated renal flow pulsatility is associated with the presence of CKD in each age group and also with biomarker levels that reflect CKD progression.

Associations Between Arterial Stiffness Indices and Chronic Kidney Disease Categories in Essential Hypertensive Patients

BACKGROUND

This study investigated the association between arterial stiffness indices and asymptomatic chronic kidney disease (CKD) risk categories in hypertensive patients.

METHODS

Arterial stiffness indices, including 24-hour brachial and aortic systolic blood pressure (SBP) and pulse wave velocity (PWV), were measured by an oscillometric Mobil-O-Graph device, brachial-ankle PWV (baPWV) by a volume-plethysmographic method, and renal resistive index (RI) by ultrasonography, in 184 essential hypertensive patients (66.0 ± 17.1 years, 47.3% male). CKD was categorized into 3 stages based on the Kidney Disease Improving Global Outcomes (KDIGO) criteria, using a combination of estimated glomerular filtration and albuminuria.

RESULTS

The 24-hour aortic PWV (aPWV), baPWV, and RI increased with worsening severity of CKD risk category (all P < 0.01 for trend). Multivariate logistic regression analysis found that a 1 SD increase of nighttime aortic SBP (odds ratio [OR] 1.52), PWV (OR 4.80), or RI (OR 1.75) was an independent predictor of high or very-high CKD stage (all P < 0.05). After adjustment for potential confounders, day-to-night change in brachial SBP as well as in aPWV differed among groups (P < 0.05, respectively). In a multivariate regression model, day-to-night changes in aortic SBP and PWV, and RI were independently associated with day-to-night brachial SBP change.

CONCLUSIONS

In hypertension, circadian hemodynamics in high CKD stage are characterized by higher nighttime values of aortic SBP and PWV and disturbed intrarenal hemodynamics. Further, the blunted nocturnal BP reduction in these patients might be mediated via disturbed intrarenal hemodynamics and circadian hemodynamic variation in aortic SBP and arterial stiffness.

Associations of Renal Augmented Velocity Index with Arterial Stiffness, Carotid Intima-Media Thickness and Blood Pressure, in Comparison with Renal Resistive Index

The augmented velocity index (Avi) is a new Doppler index associated with arterial stiffness. We examined associations of renal Avi with blood pressure (BP), aortic stiffness and carotid intima-media thickness (IMT), and compared its performance with that of resistive index (RI). One hundred forty-seven volunteers were recruited. Renal Avi had significant positive correlations with systolic BP (r = 0.37, p < 0.001), diastolic BP (r = 0.2, p = 0.016), mean arterial pressure (r = 0.29, p < 0.001), pulse pressure (r = 0.31, p < 0.001), carotid-femoral pulse wave velocity (r = 0.49, p < 0.001) and carotid IMT (r = 0.23, p = 0.005). RI correlated positively with pulse pressure (r = 0.3, p < 0.001) only. After adjustments for co-variables, the associations remained similar. Patients with abnormal BP values (≥130/80 mm Hg), IMT and aortic stiffness (≥1 standard deviation of mean value) had higher Avi than those with normal values, but not RI. In conclusion, renal Avi had stronger associations with BP, arterial stiffness and carotid IMT than RI in apparently healthy volunteers, and was significantly increased in abnormal patients.

Longitudinal Study of Brachial-Ankle Pulse Wave Velocity and Change in Estimated Glomerular Filtration Rate among Chinese Adults

BACKGROUND AND OBJECTIVES

Studies on the association between arterial stiffness and kidney function have generated inconsistent results. Whether arterial stiffness is linked to decline in renal function warrants further study. This study aimed to investigate the association between brachial-ankle pulse wave velocity (baPWV) and longitudinal change in estimated glomerular filtration rate (eGFR) among Chinese adults.

METHODS

In this longitudinal study, 8,264 participants in a community-based cohort had baPWV measured in 2010-2011 and were followed in subsequent surveys through to 2016. During each survey visit, fasting blood samples were collected for serum creatinine and eGFR was calculated. Participants were divided into 5 groups (Q1-Q5) by baPWV quintile. The association between baPWV and longitudinal changes in eGFR was assessed using generalized estimating equation models.

RESULTS

A total of 8,045 participants were included in the final analysis. The average age was 54 ± 12 years (age range 24-97 years), and mean eGFR was 93.0 ± 18.6 mL/min/1.73 m2. There was an inverse linear association between baseline baPWV and eGFR change rate (p < 0.001). Compared with Q1 (lowest) group, the mean differences and 95% CI in eGFR decrease rate among Q2-Q5 groups were -0.23 (-0.62, 0.16), -0.67 (-1.06, -0.28), -1.11 (-1.50, -0.72), and -1.30 (-1.69, -0.92) mL/min/1.73 m2 per year, respectively, after adjustment for age, gender, and other potential confounders (p trend < 0.0001). For each 100 cm/s increase in baPWV at baseline, the fully adjusted mean difference in eGFR decrease rate was -0.14 mL/min/1.73 m2 per year (95% CI -0.18, -0.10; p < 0.0001). Compared with participants with baPWV < 1,400 cm/s, the fully adjusted mean difference in eGFR decrease rate was -0.92 mL/min/1.73 m2 per year (95% CI -1.18, -0.66) for those with baPWV ≥ 1,400 cm/s (p < 0.0001).

CONCLUSIONS

Participants with a higher baPWV at baseline had a greater decrease in eGFR over time. Future studies could examine the relationship between baPWV and decline in renal function in higher risk cohorts, and its potential role in targeting reno-protective interventions to those who may benefit from them most.

Risk Factors for CKD Progression: Overview of Findings from the CRIC Study

The Chronic Renal Insufficiency Cohort (CRIC) Study is an ongoing, multicenter, longitudinal study of nearly 5500 adults with CKD in the United States. Over the past 10 years, the CRIC Study has made significant contributions to the understanding of factors associated with CKD progression. This review summarizes findings from longitudinal studies evaluating risk factors associated with CKD progression in the CRIC Study, grouped into the following six thematic categories: (1) sociodemographic and economic (sex, race/ethnicity, and nephrology care); (2) behavioral (healthy lifestyle, diet, and sleep); (3) genetic (apoL1, genome-wide association study, and renin-angiotensin-aldosterone system pathway genes); (4) cardiovascular (atrial fibrillation, hypertension, and vascular stiffness); (5) metabolic (fibroblast growth factor 23 and urinary oxalate); and (6) novel factors (AKI and biomarkers of kidney injury). Additionally, we highlight areas where future research is needed, and opportunities for interdisciplinary collaboration.

Relationship of choroidal thickness with pulsatile hemodynamics in essential hypertensive patients

Controversy exists about the association of choroidal thickness (CTh) with blood pressure (BP) values. There is some evidence suggesting that central hemodynamics changes are associated with microvascular disease. Our study was aimed to assess the relationships between CTh and clinic and 24‐h BP and between CTh and estimated 24‐h aortic pulse pressure (aPP), 24‐h aortic systolic BP (aSBP), and 24‐h aortic augmentation index (aAIx) in a group of hypertensive patients. We enrolled 158 hypertensive subjects (mean age 48 ± 13 years) all of which underwent evaluation of the choroidal district by Swept‐Source optical coherence tomography (SS‐OCT) and 24‐h BP monitoring, in order to measure peripheral BP and to estimate central hemodynamic parameters. Inverse significant correlations of clinic PP, 24‐h aPP, 24‐h aSBP, and 24‐h aAIx with thicknesses of central ring, inner ring, and outer ring of the choroid and its overall average were found. The strongest of these correlations was that relating 24‐h aPP with overall average choroidal thickness (r = −.531; P < .001). When we divided the study population in subjects with 24‐h aPP above and below the median value (35 mm Hg), CTh were thinner in subjects with higher values of 24‐aPP as compared to those with lower ones, even after adjustment for age, and other potential confounders. The relationships of CTh with 24‐h aPP remained significant also taking into account the effects of various covariates in linear multiple regression analyses. Our findings support the concept of a cross‐talk between macro‐ and microcirculation.

Physiological Age- and Sex-Related Profiles for Local (Aortic) and Regional (Carotid-Femoral, Carotid-Radial) Pulse Wave Velocity and Center-to-Periphery Stiffness Gradient, with and without Blood Pressure Adjustments: Reference Intervals and Agreement between Methods in Healthy Subjects (3-84 Years)

In addition to being a marker of cardiovascular (CV) aging, aortic stiffening has been shown to be independently associated with increased CV risk (directly and/or indirectly due to stiffness-gradient attenuation). Arterial stiffness determines the rate at which the pulse pressure wave propagates (i.e., pulse wave velocity, PWV). Thus, propagated PWV (i.e., the distance between pressure-wave recording sites divided by the pulse transit time) was proposed as an arterial stiffness index. Presently, aortic PWV is considered a gold-standard for non-invasive stiffness evaluation. The limitations ascribed to PWV have hampered its use in clinical practice. To overcome the limitations, different approaches and parameters have been proposed (e.g., local PWV obtained by wave separation and pulse wave analysis). In turn, it has been proposed to determine PWV considering blood pressure (BP) levels (β-PWV), so as to evaluate intrinsic arterial stiffness. It is unknown whether the different approaches used to assess PWV or β-PWV are equivalent and there are few data regarding age- and sex-related reference intervals (RIs) for regional and local PWV, β-PWV and PWV ratio.

AIMS

(1) to evaluate agreement between data from different stiffness indexes, (2) to determine the need for sex-specific RIs, and (3) to define RIs for PWV, β-PWV and PWV ratio in a cohort of healthy children, adolescents and adults.

METHODS

3619 subjects (3-90 y) were included, 1289 were healthy and non-exposed to CV risk factors. Carotid-femoral (cfPWV) and carotid-radial (crPWV) PWV were measured (SphygmoCor System (SCOR)) and PWV ratio (cfPWV/crPWV) was quantified. Local aortic PWV was obtained directly from carotid waves (aoPWV-Carotid; SCOR) and indirectly (generalized transfer function use) from radial (aoPWV-Radial; SCOR) and brachial (aoPWV-Brachial; Mobil-O-Graph system (MOG)) recordings. β-PWV was assessed by means of cardio-ankle brachial (CAVI) and BP-corrected CAVI (CAVIo) indexes. Analyses were done before and after adjustment for BP. Data agreement was analyzed (correlation, Bland-Altman). Mean and standard deviation (age- and sex-related) equations were obtained for PWV parameters (regression methods based on fractional polynomials).

RESULTS

The methods and parameters used to assess aortic stiffness showed different association levels. Stiffness data were not equivalent but showed systematic and proportional errors. The need for sex-specific RIs depended on the parameter and/or age considered. RIs were defined for all the studied parameters. The study provides the largest data set related to agreement and RIs for stiffness parameters obtained in a single population.

Rotating Night Shift Work, Exposure to Light at Night, and Glomerular Filtration Rate: Baseline Results from a Chinese Occupational Cohort

The misalignment between the circadian clock and behavioral cycles has been implicated in pathogenesis of many diseases. The main purpose of this study is to examine the association between rotating night shift work, exposure to light at night, and glomerular filtration rate among steelworkers in north China. A total of 6869 steelworkers, aged 22 to 60 years, were included in this study. Multivariable logistic regression was used to examine the association between night shift work, the brightness of bedroom ambient light at night (LAN), and estimated glomerular filtration rate (eGFR), with adjustment for potential confounders. Mediation analysis was performed to examine the mediation effect of potential mediators on the association of duration of night shifts and eGFR. Long duration of night shift work (≥29 years) had elevated odds of decreased eGFR (≤89 mL/min/1.73 m²) (odds ratio (OR), 1.37, 95% confidence interval (CI) 1.09–1.73) compared with day work after adjustment for potential confounders. The association between duration of night shifts and eGFR (continuous) was partially modified by diastolic blood pressure (average causal mediation effect (ACME), –0.077, 95% CI –0.134 to −0.030, p < 0.001). No significant associations were observed among the different brightness of bedroom ambient light levels: middle level (OR, 0.90, 95% CI 0.77–1.05), lightest level (OR, 0.94, 95% CI 0.75–1.18), and decreased eGFR compared with the darkest level. Long-term night-shift work, rather than the brightness of bedroom ambient LAN, is associated with early stage of renal dysfunction in steelworkers, and blood pressure may mediate the relationship between night shift work and decreased eGFR.

Relations of aortic stiffness with arterial damage beyond brachial pressure are both dependent and independent of central arterial pulsatile load

AIM

We aimed to determine whether the impact of aortic stiffness on atherosclerotic or small vessel end organ damage beyond brachial blood pressure depends in-part on stiffness-induced increases in central arterial pressures produced by an enhanced resistance to flow (characteristic impedance, Zc).

METHODS

We studied 1021 participants, 287 with stroke or critical limb ischaemia, and 734 from a community sample with atherosclerotic or small vessel end organ measures. Central arterial haemodynamics were determined from arterial pressure (SphygmoCor) and velocity and diameter assessments in the outflow tract (echocardiography).

RESULTS

Although Zc and carotid-femoral pulse wave velocity (PWV) were correlated (P < 0.0001), these relations were not independent of confounders (P = 0.90). Both Zc and hence central arterial pressures generated by the product of Zc and aortic flow (Q) (PQxZc), as well as PWV were independently associated with carotid intima-media thickness, estimated glomerular filtration rate (eGFR), endothelial activation markers [vascular cell adhesion molecule-1 (V-CAM-1)] and events. With further adjustments for brachial pulse pressure (PP) or SBP, PWV and PQxZc were both associated with eGFR and V-CAM-1. Relationships between PWV and eGFR or V-CAM-1 were independent of PQxZc (P < 0.05) and relationships between PQxZc and eGFR and V-CAM-1 were independent of PWV (P < 0.005). Similarly, with adjustments for confounders and brachial PP or SBP, across the full adult lifespan, both aortic PWV and PQxZc were increased in those with arterial events (P < 0.005). Relationships between PWV and events were again independent of PQxZc (P < 0.005) and between PQxZc and events were independent of PWV (P < 0.0001).

CONCLUSION

Beyond brachial blood pressure, the impact of aortic stiffness on arterial damage involves effects that are both dependent (proximal aortic Zc and hence PQxZc) and independent (full aortic length indexed by PWV) of central arterial pulsatile load. Hence, PWV and brachial PP may be insufficient to account for all of the damage mediated by increases in aortic stiffness.

Association of Arterial Stiffness With Kidney Function Among Adults Without Chronic Kidney Disease

BACKGROUND

Our aims were to assess whether arterial stiffness is associated with a higher risk for kidney dysfunction among persons without chronic kidney disease (CKD).

METHODS

We analyzed data from the national health checkup system in Japan; for our analyses, we selected records of individuals who completed assessments of cardio-ankle vascular index (CAVI) and kidney function from 2005 to 2016. We excluded participants who had CKD at baseline, defined as the presence of proteinuria or estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m². We compared 2 groups of CAVI measurements—the highest quartile (≧8.1) and the combined lower 3 quartiles (<8.1). We used Cox proportional hazards models to assess associations between these 2 groups and subsequent CKD events, proteinuria, eGFR <60 ml/min/1.73 m², and rapid eGFR decline (greater than or equal to −3 ml/min/1.73 m2 per year).

RESULTS

The mean age of the 24,297 included participants was 46.2 years, and 60% were female. Over a mean follow-up of 3.1 years, 1,435 CKD events occurred. In a multivariable analysis, the hazard ratios with 95% confidence intervals (CIs) for the highest vs. combined lower quartiles of CAVI measurements were 1.3 (1.1, 1.5) for CKD events, 1.3 (0.96, 1.62) for proteinuria, 1.4 (1.1, 1.7) for eGFR <60 ml/min/1.73 m², and the odds ratio with 95% CI was 1.3 (1.1, 1.4) for rapid eGFR decline.

CONCLUSIONS

Persons with CAVI measurements ≧8.1 had a higher risk for CKD events compared with their counterparts with CAVI measurements <8.1. Greater arterial stiffness among adults without CKD may be associated with kidney dysfunction.

Sodium Intake Is Associated With Renal Resistive Index in an Adult Population-Based Study

Renal resistive index (RRI) has been associated with adverse renal and cardiovascular outcomes. Although traditionally considered a marker of intrinsic renal damage, RRI could also reflect systemic vascular dysfunction. As sodium intake was linked to alterations in vascular properties, we wished to characterize the association of salt consumption with RRI in the general adult population. Participants were recruited in a population-based study in Switzerland. RRI was measured by ultrasound in 3 segmental arteries. Sodium intake (UNa; mmol/24 h) was estimated on 24-hour urine samples. Carotido-femoral pulse wave velocity was obtained by applanation tonometry. Mixed multivariate regression models were used with RRI or pulse wave velocity as independent variables and UNa as dependent variable, adjusting for possible confounders. We included 1002 patients in the analyses with 528 (52.7%) women and mean age of 47.2±17.4. Mean values of UNa and RRI were 141.8±61.1 mmol/24 h and 63.8±5.5%, respectively. In multivariate analysis, UNa was positively associated with RRI (P=0.002) but not with pulse wave velocity (P=0.344). Plasma renin activity and aldosterone did not modify the relationship between UNa and RRI (P=0.087 for interaction). UNa/urinary potassium ratio was positively associated with pulse wave velocity ≥12 m/s (P=0.033). Our results suggest that dietary salt consumption has a direct impact on renal hemodynamic in the adult general population. Alterations in vascular properties likely explain those findings, but inadequate renal vaso-motor response is also possible. Sodium intake could thus potentially be linked to underlying structural systemic damages affecting this population.

Nocturnal hypertension: a common phenotype in a tertiary clinical setting associated with increased arterial stiffness and central blood pressure

OBJECTIVE

Although the detrimental effect of increased mean blood pressure (BP) is well established, the role of the dynamic and circadian features of BP is less well defined but may be similarly important. In this prospective analysis of hypertensive patients from a tertiary hospital hypertension clinic, we investigated whether the presence of night-time systolic hypertension is associated with more pronounced end-organ damage as assessed by measures of pulse wave analysis (PWA) and pulse wave velocity (PWV).

METHODS

A cohort of 222 consecutive hypertensive patients underwent ambulatory blood pressure measurements, PWA, PWV testing and collection of routine clinical data. Group differences and group-effects of daytime and night-time hypertension on target organ damage and cardiovascular risk parameters were analysed.

RESULTS

Nocturnal hypertension was evident in more than half of the study population. PWV, central systolic, mean arterial and pulse pressure were higher in patients with nocturnal hypertension. Stratification into four groups according to daytime and night-time hypertension status revealed group differences in all outcome parameters. Posthoc testing for individual group differences demonstrated significant differences between fully controlled individuals and the group with high daytime and night-time BP. In a regression analysis for independent effects of categorical night-time and daytime hypertension, nocturnal hypertension was a significant predictor for all PWA and PWV outcomes.

CONCLUSION

Nocturnal hypertension was a highly prevalent phenotype in this population and associated with increased central BP and more pronounced target organ damage as indicated by elevated PWV. Regression analysis confirmed the role of night-time hypertension as an independent explanatory variable for elevated PWV.

The association between the renal resistive index and the myocardial performance index in the general population

OBJECTIVE

The renal resistive index (RRI) is the most described measure of renal hemodynamics. The myocardial performance index (MPI) is widely used to assess overall myocardial performance. In this study, we aimed to investigate the relationship between renal hemodynamics, assessed by the RRI, and cardiac functions, assessed by the MPI in the general population.

METHODS

This single-center, cross-sectional study included a total of 302 consecutive patients who presented to our outpatient cardiology clinic between October 2019 and February 2020. All patients underwent transthoracic echocardiography and renal Doppler ultrasonography. The study population was divided into two groups: low RRI group (RRI ≤ 0.7, n = 236) and high RRI group (RRI > 0.7, n = 66).

RESULTS

E/A ratio, left ventricular ejection fraction (LVEF), and the MPI were significantly higher in the high RRI group than in the low RRI group (61.3 ± 15.4 vs 55.3 ± 16.4, P = .010 for E velocity; 0.9 ± 0.3 vs 0.7 ± 0.2, P = .008 for E/A ratio; 57.7 ± 4.7 vs 53.2 ± 10.1, P = .029 for LVEF; 0.52 ± 0.1 vs 0.43 ± 0.1, P < .001 for the MPI). A stepwise linear regression analysis demonstrated that LVEF (β = .123, P = .026), E velocity (β = .221, P < .001), and the MPI (β = .392, P < .001) were independently associated with the RRI.

CONCLUSION

Left ventricular ejection fraction and intra-cardiac Doppler blood flow indices, including E velocity and the MPI, were significantly and independently associated with the RRI in the general population.

Postoperative Ultrasound in Kidney Transplant Recipients: Association Between Intrarenal Resistance Index and Cardiovascular Events

Doppler ultrasound, including intrarenal resistance index (RI) measurement, is a widely used modality to assess kidney transplantation (KTx) vascularization. The aim of this study is to gain insight in the associations between early postoperative RI measurements and cardiovascular events (CVEs), all-cause mortality, and death-censored graft survival.

METHODS

From 2015 to 2017, a prospective cohort study was conducted in patients in which RI measurement was performed immediately after KTx. The RI was calculated as (peak systolic velocity-end-diastolic velocity)/peak systolic velocity. End points were CVEs, all-cause mortality, and graft failure. Kaplan-Meier analyses (logrank test) were used for differences in end points. Univariate and multivariate associations were investigated by means of Cox regression analyses.

RESULTS

RI cutoff of 0.70 was used. We included 339 recipients, of which 271 (80%) had an RI ≤ 0.70 and 68 (20%) had an RI > 0.70. CVEs were observed in 27 (8%) patients, 27 (8%) patients died, and 17 (5%) patients had graft failure during a median follow-up of 37 months (interquartile range, 33-43). Kaplan-Meier analyses and univariate Cox regression indicated a significant association with overall CVE-free survival (hazard ratios [HR], 2.79; P = 0.011; logrank test, P = 0.008) and all-cause mortality (HR, 2.59; P = 0.017; logrank test, P = 0.013) for patients with an RI above and below 0.70. An independent association was shown between an RI > 0.70 and CVE-free survival (HR, 2.48; P = 0.042) when deceased donation was not included in the model.

CONCLUSIONS

In the early postoperative period, a high RI showed to be associated with CVEs after adjustment for cardiovascular risk factors, whereas no independent association was found with overall survival and graft failure. For the interpretation of RI measurements after KTx surgery, patients' cardiovascular state should be taken into consideration.