Association of microalbuminuria with brachial-ankle pulse wave velocity: the Ohasama study

Associations of blood biomarkers with arterial stiffness in patients with diabetes mellitus: A population-based study

BACKGROUND

Arterial stiffness contributes to additional cardiovascular risks in diabetic patients by triggering the loss of vascular and myocardial compliance and promoting endothelial dysfunction. Thus, prevention of arterial stiffness is a public health priority, and the identification of potential biomarkers may provide benefits for early prevention. This study investigates the relationships between serum laboratory tests and pulse wave velocity (PWV) tests. We also investigated the associations between PWV and all-cause mortality.

METHODS

We examined a panel of 33 blood biomarkers among diabetic populations in the Atherosclerosis Risk in Communities Study. The carotid-femoral (cfPWV) and femoral-ankle PWV (faPWV) were measured using an automated cardiovascular screening device. The aortic-femoral arterial stiffness gradient (afSG) was calculated as faPWV divided by cfPWV. Biomarker levels were log-transformed and correlated with PWV. Cox proportional hazard models were employed for survival analysis.

RESULTS

Among 1079 diabetic patients, biomarkers including high-density lipoprotein cholesterol, glycated hemoglobin, high-sensitivity troponin T, cystatin C, creatinine, and albuminuria were significantly correlated with afSG (R = 0.078, -0.193, -0.155, -0.153, -0.116, and -0.137, respectively) and cfPWV (R = -0.068, 0.175, 0.128, 0.066, 0.202, and 0.062, respectively). Compared with the lowest tertile of afSG, the risk of all-cause mortality was lower in the highest tertile (hazard ratio 0.543; 95% confidence interval 0.328-0.900).

CONCLUSION

Certain biomarkers related to blood glucose monitoring, myocardial injury, and renal function significantly correlated with PWV, suggesting that these putative risk factors are likely to be important atherosclerosis mechanisms in diabetic patients. AfSG may be an independent predictor of mortality among diabetic populations.

Comparison of brachial-ankle pulse wave velocity and carotid-femoral pulse wave velocity in association with albuminuria in a community of Beijing: a cross-sectional study

This study was performed to investigate and compare the association of albuminuria with the brachial-ankle pulse wave velocity (baPWV) and carotid-femoral pulse wave velocity (cfPWV) in a community-based population in Beijing. Subjects were enrolled from a follow-up survey conducted in 2018 from an atherosclerosis cohort in Shijingshan district, Beijing, China. The baPWV and cfPWV were measured using a BP-203 RPE III arteriosclerosis detection device and PulsePen, respectively. Albuminuria was defined as a urinary albumin-creatinine ratio of ≥30 mg/g. A multivariate logistic regression model was used to evaluate the impacts of different PWV measurements on the prevalence of albuminuria. In total, 5605 subjects were included in the analyses. Their mean age was 62.22 ± 7.55 years, and the prevalence of albuminuria was 8.22%. In the multivariate logistic regression model adjusted for potential covariates, both baPWV (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.03-1.10; P < 0.001) and cfPWV (OR, 1.07; 95% CI, 1.01-1.14; P = 0.018) were significantly associated with albuminuria. Furthermore, when baPWV and cfPWV were entered into the logistic regression model simultaneously, only baPWV was significantly associated with albuminuria using either continuous value (OR, 1.05; 95% CI, 1.01-1.10; P = 0.007) or classified into quartiles (highest vs. lowest value group: OR, 1.55; 95% CI, 1.01-2.37; P for trend = 0.019). Both cfPWV and baPWV were positively associated with albuminuria, while baPWV had a stronger relationship than cfPWV. Thus, baPWV measurement could be considered for the purpose of community health screening.

Association between Brachial-Ankle Pulse Wave Velocity and Microalbuminuria and to Predict the Risk for the Development of Microalbuminuria Using Brachial-Ankle Pulse Wave Velocity Measurement in Type 2 Diabetes Mellitus Patients

Brachial-ankle pulse wave velocity (baPWV) provides a useful means of assessing cardiovascular events and diabetic complications. However, the nature of associations between baPWV and microalbuminuria (MAU) and its presence in Type 2 diabetes mellitus (Type 2 DM) have rarely been investigated. This study aimed to examine the association between baPWV and MAU coupled with prediction of MAU using baPWV measurement among Type 2 DM patients. In this cross-sectional study, we enrolled 424 Type 2 DM patients who visited the cardiology and endocrinology department at a tertiary level health care facility, Republic of Korea between 1 January 2006 to 31 December 2008. Clinical and laboratory data were collected, and risk factors associated with MAU and prediction of risk for the development of MAU using baPWV measurement. The association between MAU and baPWV was examined using multivariable logistic regression analysis and predicted MAU by using receiver operating characteristic (ROC) curve analysis. Of the 424 Type 2 DM patients, 93 (21.9%) had MAU (20-200 μg/min). baPWV (cm/sec) was found to be significantly correlated with MAU levels (ug/min) (r = 0.791, p < 0.001). Further, baPWV was significantly associated MAU with higher odds ratio (adjusted odds ratio (AOR) 10.899; 95% confidence interval (CI) (4.518-26.292)). Similarly, smoking (AOR 10.899; 95% CI (4.518-26.292)), and low-density lipoprotein (LDL)-cholesterol (mg/dL) (AOR 1.017; 95% CI (1.001-1.033)) were also significantly associated with MAU. The appropriate cut-off value for baPWV to predict MAU 20 μg/min in our study was 1700 cm/sec (area under ROC curve = 0.976). This study shows that baPWV, cigarette smoking, and LDL-cholesterol are associated with MAU in Type 2 DM patients and suggests that a baPWV cut-off of 1700 cm/sec could be used to predict the presence of MAU (20 μg/min) in Type 2 DM patients in the Korean community.

Aldosterone breakthrough does not alter central hemodynamics

Introduction:

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are widely used in congestive heart failure and chronic kidney disease, but up to 40% of patients will experience aldosterone breakthrough, with aldosterone levels rising above pre-treatment levels after 6–12 months of renin-angiotensin-aldosterone system blockade. Aldosterone breakthrough has been associated with worsening congestive heart failure and chronic kidney disease, yet the pathophysiology remains unclear. Breakthrough has not been associated with elevated peripheral blood pressure, but no studies have assessed its effect on central blood pressure.

Methods:

Nineteen subjects with well-controlled peripheral blood pressure on stable doses of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker had aldosterone levels checked and central blood pressure parameters measured using the SphygmoCor system. The central blood pressure parameters of subjects with or without breakthrough, defined as serum aldosterone >15 ng/dl, were compared.

Results:

Of the 19 subjects, six had breakthrough with a mean aldosterone level of 33.8 ng/dl, and 13 were without breakthrough with a mean level of 7.1 ng/dl. There was no significant difference between the two groups in any central blood pressure parameter.

Conclusions:

We found no correlation between aldosterone breakthrough and central blood pressure. The clinical impact of aldosterone breakthrough likely depends on its non-genomic, pro-fibrotic, pro-inflammatory effects rather than its regulation of extracellular volume.

Arterial Stiffness is an Independent Risk Factor for Anemia After Percutaneous Native Kidney Biopsy

BACKGROUND/AIMS

Bleeding is the most common complication after renal biopsy. Although numerous predictors of bleeding have been reported, it remains unclear whether arterial stiffness affects bleeding complications.

METHOD

We performed an observational study of the renal biopsies performed in our division over an approximately 6-year period (May 2010 to May 2016). The clinical and laboratory factors were analyzed to reveal the risk factors associated with bleeding, with a focus on anemia (defined as a ≥10% decrease in hemoglobin [Hb] after biopsy). The brachial-ankle pulse wave velocity (baPWV) was measured to evaluate arterial stiffness.

RESULTS

This study included 462 patients (male, n=244; female, n=218). Anemia (defined above) was observed in 54 patients (11.7%). The risk of anemia was higher in women, older patients, and patients with lower serum albumin, lower eGFR and lower diastolic blood pressure after biopsy. We then performed a further analysis of 187 patients whose baPWV data were available. Multivariate analysis revealed that a higher baPWV was an independent risk factor for anemia. ROC analysis for predicting anemia found that a baPWV value of 1839 cm/s had the best performance (AUC 0.689).

CONCLUSION

An increased baPWV may be a more valuable predictor of bleeding than any of the other reported risk factors.

The renal tubular damage marker urinary N-acetyl-β-D-glucosaminidase may be more closely associated with early detection of atherosclerosis than the glomerular damage marker albuminuria in patients with type 2 diabetes

Background

To determine the association between urinary N-acetyl-β-d-glucosaminidase (NAG), a marker of renal tubulopathy, and carotid intima-media thickness (IMT) and plaques in patients with type 2 diabetes mellitus (T2D) and to compare the predictive value of NAG versus albuminuria, a marker of renal glomerulopathy.

Methods

A total of 343 participants were enrolled in this retrospective cross-sectional study. We recruited participants with T2D who were tested for blood glucose parameters, urinary NAG, and urinary albumin-to-creatinine ratio (ACR) and had been checked for carotid ultrasonography.

Results

We classified participants into a below-median urinary NAG group (Group I; n = 172) or an above-median group (Group II; n = 171). Mean, maximum, and mean of maximum carotid IMT and the proportion of patients with carotid plaques were significantly higher in Group II compared with Group I. In multiple linear regression analyses, high urinary NAG (Group II) was significantly associated with carotid IMT, independently of urinary ACR and other confounding factors. In terms of carotid plaques, both urinary NAG and ACR were significantly higher in participants with carotid plaques than in those without carotid plaques. After adjustment for confounding factors, both urinary NAG and ACR were significantly associated with the presence of carotid plaques.

Conclusions

Elevated urinary NAG, a marker of renal tubular damage, was related to increased carotid IMT and the presence of carotid plaques in patients with T2D. Urinary NAG may be a more sensitive biomarker than urinary albumin for early detection of atherosclerosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0497-7) contains supplementary material, which is available to authorized users.

Arteriosclerotic Changes after Intravitreal Injections of Anti-Vascular Endothelial Growth Factor Drugs in Patients with Exudative Age-Related Macular Degeneration

PURPOSE

The aim of this study was to determine whether multiple intravitreal injections of anti-vascular endothelial growth factor (VEGF) drugs for age-related macular degeneration (AMD) exacerbate systemic arteriosclerosis, using the cardio-ankle vascular index (CAVI) and intima-media thickness (IMT).

METHODS

We analyzed the data of 45 AMD patients who received intravitreal injections of anti-VEGF drugs (ranibizumab and/or aflibercept) and underwent systemic evaluations at baseline and after treatment. Reevaluation was conducted at ≥12 months from the initial treatment.

RESULTS

The total number of intravitreal injections of overall anti-VEGF drugs was significantly correlated with x0394;serum cystatin C. The cumulative number of aflibercept injections was identified as an independent protective factor for x0394;CAVI. An increase in the cumulative number of intravitreal injections of overall anti-VEGF drugs was identified as a protective factor for x0394;mean IMT.

CONCLUSION

Repeated intravitreal injections of an anti-VEGF drug for AMD may lead to morphological and functional changes in large arteries.

Genetic predisposition to albuminuria is associated with increased arterial stiffness: role of elastin

BACKGROUND AND PURPOSE

The Munich Wistar Frömter (MWF) rat strain represents an experimental model to study cardiovascular alterations under conditions of progressive albuminuria. The aim of this study was to evaluate the association between genetic predisposition to albuminuria and the development of arterial stiffness and/or vascular remodelling.

EXPERIMENTAL APPROACH

Experiments were performed in mesenteric arteries from 12-week-old MWF, Wistar Kyoto (WKY) and consomic MWF-6(SHR) and MWF-8(SHR) rats in which chromosomes 6 or 8 associated with albuminuria from MWF were replaced by the respective chromosome from spontaneously hypertensive rats (SHR).

KEY RESULTS

Incremental distensibility, wall stress and strain were reduced, and arterial stiffness was significantly increased in albuminuric MWF compared with WKY. Albuminuria suppression in both consomic strains was associated with lower β-values in MWF-8(SHR) and MWF-6(SHR) compared with MWF. Moreover, elastin content was significantly lower in MWF external elastic lamina compared with WKY and both consomic strains. In addition, a reduction in arterial external and internal diameter and cross-sectional area was detected in MWF compared with WKY, thus exhibiting an inward hypotrophic remodelling. However, these alterations remained unchanged in both consomic strains.

CONCLUSION AND IMPLICATIONS

These data demonstrate that albuminuria in MWF is associated with increased arterial stiffness due to a reduction of elastin content in the external elastic lamina. Moreover, inward hypotrophic remodelling in MWF is not directly associated with albuminuria. In contrast, we demonstrated that two major genetic loci affect both the development of albuminuria and arterial stiffness, thus linking albuminuria and impairment of mechanical properties of resistance arteries.

Albuminuria as a marker of arterial stiffness in chronic kidney disease patients

AIM: To access the association between albuminuria levels and arterial stiffness in non-diabetic patients with hypertension and chronic kidney disease (CKD) stages 1-2, treated with renin angiotensin blockade agents plus other hypertensive drugs when needed.

METHODS: One hundred fifteen patients [median age 52 years (68% males)] were consequently enrolled in the study. For each patient, we recorded gender, age, body mass index (BMI), peripheral systolic blood pressure (pSBP), peripheral diastolic blood pressure, peripheral pulse pressure, central systolic blood pressure (cSBP), central diastolic blood pressure (cDBP), central pulse pressure (cPP), hematocrit, hemoglobin, hsCRP, total cholesterol triglycerides, high-density lipoprotein-C, low-density lipoprotein-C, calcium, phosphorus, parathormone, and albumin, as well as 24 h urine albumin excretion. According to 24-h urine albumin collection, patients were then classified as those with moderately increased albuminuria (formerly called macroalbuminuria) (≤ 300 mg/d) and those with severely increased albuminuria (formerly called macroaluminuria (> 300 mg/d). We considered aortic stiffness (AS) indices [carotid femoral pulse wave velocity (PWVc-f) and augmentation index (AIx)] as primary outcomes of the study. We explored potential correlations between severely increased albuminuria and AS indices using a multiple linear regression model.

RESULTS: Fifty-eight patients were included in the moderately increased albuminuria group and 57 in the severely increased albuminuria. Blood pressure measurements of the study population were 138 ± 14/82 ± 1.3 mmHg (systolic/diastolic). There were no significant differences in age, sex, and BP measurements between the two groups. Patients with severely increased albuminuria had higher PWV and AIx than patients with moderately increased albuminuria (P < 0.02, P < 0.004, respectively). In addition these patients exhibited higher BMI (P < 0.03), hsCRP (P < 0.001), and fibrinogen levels (P < 0.02) compared to patients with moderately increased albuminuria. In multivariate linear regression analysis, severely increased albuminuria (β = 1.038, P < 0.010) pSBP (β = 0.028, P < 0.034) and Ht (β = 0.171, P = 0.001) remained independent determinants of the increased PWVc-f. Similarly, severely increased albuminuria (β = 4.385, P < 0.012), cSBP (β = 0.242, P < 0.001), cPP (β = 0.147, P < 0.01) and Ht levels (β = 0.591, P < 0.013) remained independent determinants of increased AIx.

CONCLUSION: These findings demonstrate an independent association between AS indices and severely increased albuminuria in non-diabetic, hypertensive patients with CKD stages 1-2 treated with renin angiotensin aldosterone system blockers.

Association between pulse wave velocity and a marker of renal tubular damage (N-acetyl-β-D-glucosaminidase) in patients without diabetes

The authors assessed the association between the ratio of urinary activity of N-acetyl-β-D-glucosaminidase (NAG) to creatinine and the brachial-ankle pulse wave velocity (baPWV) in patients without overt diabetes mellitus (DM). This was a cross-sectional study of 233 patients who had an estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m(2) and no history of kidney disease. Patients were divided into two groups: high NAG group (>5.8 U/g creatinine) and low NAG group (≤5.8 U/g creatinine). Mean baPWVs of the high NAG group were significantly higher than those of the low NAG group in both the eGFR ≥30 and <60 tertiles and the eGFR ≥60 and <90 tertiles. The baPWV was positively correlated with NAG in all patients (r=0.341, P<.001). Stepwise multivariate regression analysis showed that the baPWV was significantly related with NAG, age, and systolic blood pressure. Elevated NAG is related to elevated arterial stiffness in patients without DM.

High salt intake is associated with renal involvement in Japanese patients with type 2 diabetes mellitus

OBJECTIVE

The aim of our study was to investigate clinical and nutritional factors associated with renal involvement in patients with type 2 diabetes.

PATIENTS

We performed a cross-sectional study of 71 patients with type 2 diabetes who were being educated at our hospital from September 2006 to February 2008. The patients were divided into two groups; Group I consisted of 40 patients with both an estimated glomerular filtration rate (eGFR) of ≥ 60 mL/min/1.73 m(2) and normoalbuminuria, and Group II consisted of 31 patients with either microalbuminuria/overt proteinuria or an eGFR of <60 mL/min/1.73 m(2). We compared the age, body mass index (BMI), blood pressure, duration from onset of diabetes, use of hypoglycemic agents and insulin, biochemistry data, including HbA1c, pulse wave velocity corrected by blood pressure (PWVc) and the daily intake of several nutrients between the two groups. A multivariate logistic regression analysis was performed to identify factors independently associated with renal involvement.

RESULTS

Group II had significantly higher values for BMI, the duration of diabetes, triglycerides, uric acid and PWVc than Group I. Group II tended to have a high salt intake compared to Group I. The multivariate logistic analysis revealed that the daily salt intake, PWVc and uric acid were independent factors associated with renal involvement (odds ratio, 1.15, 1.84 and 2.00; 95% confidence interval, 1.02-1.31, 1.04-3.27 and 1.04-3.85, respectively).

CONCLUSION

Our data suggest that a high salt intake, in addition to arteriosclerosis, is associated with renal involvement in our cohort with type 2 diabetes.

Elevated brachial-ankle pulse wave velocity is independently associated with microalbuminuria in a rural population

Microalbuminuria is a marker of generalized endothelial dysfunction resulting from arterial stiffness or insulin resistance, and brachial-ankle pulse wave velocity (baPWV) is a good measure of arterial stiffness. We aimed to investigate whether elevated baPWV is independently associated with microalbuminuria. This study included 1,648 individuals aged over 40 who participated in the baseline Multi-Rural Cohort Study conducted in Korean rural communities between 2005 and 2006. Participants were classified into less than 30 mg/g as normoalbuminuria or 30-300 mg/g as microalbuminuriausing urinary albumin creatinine ratio (UACR). The median and Q1-Q3 baPWV values were significantly higher in the microalbuminuric group both in men (1,538, 1,370-1,777 cm/s vs. 1,776, 1,552-2,027 cm/s, P < 0.001) and women (1,461, 1,271-1,687 cm/s vs. 1,645, 1,473-1,915 cm/s, P < 0.001). BaPWV was independently associated with microalbuminuria in both genders after adjusting for pulse rate; fasting blood glucose; triglyceride; homeostatic model assessment insulin resistance (HOMAIR) and, history of hypertension and diabetes. Fasting blood sugar and HOMAIR were judged as having nothing to do with multicolinearity (r = 0.532, P < 0.001). Elevated baPWV was independently associated with microalbuminuria regardless of insulin resistance among rural subjects over 40 yr.

Arterial Stiffness Is Associated With Carotid Intraplaque Hemorrhage in the General Population

Objective—

The relation between arterial stiffness and atherosclerosis, and specifically the influence of arterial stiffness on plaque composition, is largely unknown. In a population-based study, we investigated the association between arterial stiffness and the presence and composition of carotid atherosclerotic plaques.

Approach and Results—

Arterial stiffness was measured in 6527 participants (67.0±8.6 years) using aortic pulse wave velocity (PWV). Presence of carotid atherosclerotic plaques was assessed with ultrasound. Subsequently, 1059 subjects with carotid plaques (>2.5 mm) underwent MRI to assess plaque composition (presence of intraplaque hemorrhage, lipid, and calcification). Generalized estimation equation analyses adjusted for age, sex, mean arterial pressure, heart rate, carotid wall thickening, pulse pressure, and traditional cardiovascular risk factors were used to study the association between PWV and the presence and composition of carotid atherosclerotic plaques. In multivariable analysis, higher PWV was independently related to higher prevalence of carotid atherosclerotic plaque on ultrasound (odds ratio for highest quartile of PWV compared with lowest quartile, 1.24 [95% confidence interval, 1.02–1.51]). Furthermore, higher PWV was associated with intraplaque hemorrhage (age- and sex-adjusted odds ratio per SD increase in PWV, 1.20 [1.04–1.38] and calcification, 1.18 [1.03–1.35]), but not with lipid. After adjustment for cardiovascular risk factors, PWV remained significantly associated with intraplaque hemorrhage (1.20 [1.01–1.43]). Additional adjustment for pulse pressure did not materially affect the effect estimate (1.19 [1.00–1.42]).

Conclusions—

Higher PWV is associated with presence and composition of carotid atherosclerotic plaques, in particular with intraplaque hemorrhage. These findings provide further clues for understanding the development of vulnerable atherosclerotic plaque.

Prolonged elevated postprandial sugar augments severity in kidney disease: a north Indian hospital-based study

AIM

Diabetes plays a major role in progression of renal failure. The risk-factor profile changes during the progression of chronic kidney disease (CKD) from mild/moderate to end-stage renal disease. The relationship between glycemic indices, blood pressure, body mass index (BMI) and age at diagnosis in Indians has been less investigated. We assessed association of these risk factors with CKD stages in Indian population.

METHODS

This study was carried out on patients (n = 162) who were diagnosed with CKD and normal control group (n = 155). For BMI, National Institutes for Health criteria were used to categorize the patients.

RESULT

The mean age of CKD patients were significantly increased with the advancement of stage. BMI, systolic blood pressure (SBP), postprandial sugar level (PP), urea and creatinine were also significantly higher with elevated stages, whereas no differences were observed in diastolic blood pressure (DBP) and fasting blood sugar (FBS). The logistic regression study gave a significant result (p = 0.000) when we compared the group of CKD patients with established/prolonged postprandial blood sugar. It was independently associated with mild CKD [odds ratio (OR) = 5.213, 95% confidence interval (CI) = 2.06-13.21, p = 0.000], moderate CKD (OR = 7.724, 95% CI = 4.05-14.74, p = 0.000) and severe CKD (OR = 7.610, 95% CI = 4.03-14.36, p = 0.000).

CONCLUSION

SBP and PP were the best predictors of prevalent nephropathy in this population, while DBP and FBS were found to be less effective. This may have implication for kidney disease risk stratification and protection.

Microalbuminuria is independently associated with arterial stiffness and vascular inflammation but not with carotid intima-media thickness in patients with newly diagnosed type 2 diabetes or essential hypertension

The association between microalbuminuria (MAU) and the indices of macrovascular complication in patients with newly diagnosed type 2 diabetes (D) or essential hypertension (H) was evaluated. Total 446 patients were classified into four groups according to the urinary albumin-to-creatinine ratio: MAU-D (n = 104), normoalbuminuria (NAU)-D (n = 114), MAU-H (n = 116), and NAU-H (n = 112). The indices of macrovascular complication including arterial stiffness evaluated by pulse-wave-velocity (PWV), carotid intima-media thickness (IMT), and vascular inflammation marked by high-sensitivity C-reactive protein (hsCRP) were assessed. PWV, IMT, and hsCRP were higher in patients with MAU than in those with NAU in both diabetes and hypertension groups. In both MAU-D and MAU-H groups, PWV and hsCRP levels were positively correlated with MAU level (MAU-D: r = 0.47, 0.41, MAU-H: r = 0.36, 0.62, respectively, P < 0.05). Additionally, PWV and hsCRP were independent factors predicting MAU (diabetes group: OR 1.85, 1.54, hypertension group: OR 1.38, 1.51, respectively, P < 0.001), but not IMT. MAU is independently associated with arterial stiffness and vascular inflammation but not with IMT in patients with newly diagnosed type 2 diabetes or essential hypertension, which emphasizes the importance of proactive clinical investigations for atherosclerotic complications in patients with MAU, even in newly diagnosed diabetes or hypertension.

Determining the optimal cut-off value of the urinary albumin-to-creatinine ratio to detect atherosclerotic vascular diseases

BACKGROUND

We examined whether low-grade albuminuria, below the conventional cut-off value for microalbuminuria, was associated with atherosclerotic vascular diseases in 8897 community-dwelling Koreans aged ≥50 years.

METHODS

The urinary albumin-to-creatinine ratio (UACR) was calculated using random spot urine. Common carotid artery (CCA) intimamedia thickness (IMT) and CCA internal diameter were measured using high-resolution B-mode ultrasonography, and carotid plaque was evaluated. Brachial-ankle pulse wave velocity (BaPWV) and the ankle-brachial index (ABI) were examined, and peripheral arterial disease was defined as ABI <0.9.

RESULTS

Youden's indices, predicting abnormal atherosclerotic conditions, were greatest at a UACR cut-off value of ∼15 mg/g, below the threshold conventionally used to define microalbuminuria. Compared with low normoalbuminuria (UACR <15.0 mg/g), CCA IMT, CCA diameter, and BaPWV were significantly greater in individuals with high normoalbuminuria (UACR 15.0-29.9 mg/g), who also had a significantly higher risk of carotid plaque than did those with low normoalbuminuria.

CONCLUSIONS

Subclinical atherosclerotic vascular diseases developed at lower UACRs, below the conventional classification of microalbuminuria. Further longitudinal studies are needed to investigate the relationship between microalbuminuria and the development of subclinical atherosclerosis.

Pulse-wave analysis of optic nerve head circulation is significantly correlated with brachial-ankle pulse-wave velocity, carotid intima-media thickness, and age

BACKGROUND

To determine whether there is a significant correlation between the pulse-wave analysis in the optic nerve head circulation determined by laser speckle flowgraphy (LSFG), and brachial-ankle pulse wave velocity (baPVW), carotid intima-media thickness (IMT), and age.

METHODS

Thirty-three patients who visited the Vascular Function Section in our hospital were included. Age was 57.3 ± 12.6 years, with a range from 29 to 80 years. baPVW, carotid IMT, and pulse wave analysis in optic nerve head circulation using LSFG were conducted on subjects, and this parameter is named blowout time (BOT). The following items were analyzed as other systemic parameters: age, blood pressure, pulse pressure, heart rate, body mass index, and mean arterial blood pressure; other ocular parameters were intraocular pressure and ocular perfusion pressure. Pearson's correlation coefficients were used to determine the relationship between the BOT, baPWV, IMT, age, and other parameters. In addition, multiple regression analysis was used to determine independent factors for age.

RESULTS

BOT was significantly correlated with age (r = -0.85, P <0.0001), pulse pressure (r = -0.36, P = 0.04), baPWV (r = -0.72, P <0.0001), and IMT (r = -0.64, P < 0.0001). The result of multiple regression analysis showed that baPWV (odds ratio = 0.93, 95% confidence interval = 0.03-1.82 P = 0.04) and BOT (-2.26, -3.27 to -1.26, <0.0001) were independent contribution factors to age.

CONCLUSIONS

Our results confirmed measurements of BOT in the optic nerve head can be a useful method for determinin g whether early atherosclerotic changes are present in the optic nerve head circulation.

Factors associated with brachial-ankle pulse wave velocity in the general population

The present study investigated factors that modify or affect arterial stiffness as assessed by brachial-ankle pulse wave velocity (baPWV) in the general population. Subjects had previously participated in a physical checkup program (n=911), and baPWV and urinary albumin and sodium excretion were also measured. Urine albumin was expressed as the ratio of urine albumin to urine creatinine. Individual salt intake was assessed by estimating 24-h urinary salt excretion and expressed as the ratio of estimated salt intake to body weight. The mean blood pressure and baPWV were 127.1±15.2/77.0±9.5 mm Hg and 15.9±3.3 m s(-1), respectively. Univariate analysis demonstrated that baPWV correlated with various factors including age, blood pressure, electrocardiogram voltage (SV(1)+RV(5)), urine albumin and salt intake. Multivariate regression analysis revealed that electrocardiogram voltage (P<0.001), systolic blood pressure (P<0.0001), urine albumin (P<0.001) and salt intake (P<0.001), independently correlated with baPWV after adjustment for other possible factors. Similar results were obtained for participants not taking any medication. These results suggest that the baPWV value is independently associated with individual salt intake and cardiac and renal damage, and could be a useful procedure for identifying individuals with concealed risk of cardiovascular disease.

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

A significant link has been reported between aortic stiffening and renal microvascular damage, but the underlying mechanism remains poorly understood. We hypothesized that alterations in central and renal hemodynamics are responsible for this link. In 133 patients with hypertension, pressure waveforms were recorded on the radial, carotid, femoral, and dorsalis pedis arteries with applanation tonometry to estimate the aortic pressures and aortic (carotid-femoral) and peripheral (carotid-radial and femoral-dorsalis pedis) pulse wave velocities. Flow-velocity waveforms were recorded on the renal segmental arteries with duplex ultrasound to calculate the resistive index (RI) as [1 - (end-diastolic velocity/peak systolic velocity)] and on the femoral arteries to calculate the reverse/forward flow index and diastolic/systolic forward-flow ratio. Albuminuria was defined as urinary albumin/creatinine ratio ≥30 mg/g of creatinine. The renal RI (mean: 0.65±0.07) was strongly correlated (P<0.001) with the aortic pulse pressure (r=0.62), incident pressure wave (r=0.55), augmented pressure (r=0.49), and aortic pulse wave velocity (r=0.51), although not with the mean arterial pressure or peripheral pulse wave velocities. The correlations remained highly significant after consideration of confounders including age, cholesterol, hemoglobin A(1c), and glomerular filtration rate. The renal RI was inversely correlated with the femoral reverse and diastolic forward flow indices. Both aortic pulse pressure and renal RI correlated with the urinary albumin/creatinine ratio independent of confounders. Each 0.1 increase in renal RI was associated with a 5.4-fold increase in the adjusted relative risk of albuminuria. In conclusion, increased aortic pulse pressure causes renal microvascular damage through altered renal hemodynamics resulting from increased peripheral resistance and/or increased flow pulsation.

Association between home arterial stiffness index and target organ damage in hypertension: comparison with pulse wave velocity and augmentation index

OBJECTIVES

To clarify the implications of the home arterial stiffness index (HASI), we compared HASI with other arterial stiffness measures and investigated the association between HASI and hypertensive target organ damage (TOD).

METHODS

We assessed brachial-ankle pulse wave velocity (baPWV) and the carotid augmentation index (cAIx) as measures of arterial stiffness and wave reflection, and the left ventricular mass index (LVMI), carotid intima-media thickness (IMT) using ultrasonography, and the urinary albumin/creatinine ratio (UACR) as measures of TOD in 356 never-treated hypertensive subjects. Home blood pressure (BP) was taken in triplicate in the morning and evening, respectively, for 14 consecutive days with a memory-equipped device. HASI was defined as 1 minus the respective regression slope of diastolic on systolic BP.

RESULTS

HASI was significantly correlated with age (r = 0.32, P < 0.001), home pulse pressure (r = 0.36, P < 0.001), morning-evening difference in home systolic BP (r = -0.29, P < 0.001), baPWV (r = 0.18, P < 0.001), cAIx (r = 0.16, P = 0.002), carotid IMT (r = 0.26, P < 0.001), and UACR (r = 0.24, P < 0.001), but not with LVMI (r = 0.05, P = 0.38). After adjustment for age and sex, the significant correlation between HASI and baPWV/cAIx was lost. In multivariate regression analyses, HASI and baPWV were significantly associated with carotid IMT (standardized β = 0.21, P<0.001; β = 0.14, P = 0.014) and UACR (β = 0.13, P = 0.018; β = 0.21, P < 0.001), independently of age, sex, and home mean arterial pressure. On the other hand, cAIx was independently associated only with LVMI (β = 0.24, P < 0.001).

CONCLUSION

These findings indicate that HASI adds nothing to the existing measures of arterial stiffness, but might be a BP component that can aid in the detection of carotid atherosclerosis and renal damage, similar to PWV.

Cardio-Kidney-Damage: a unifying concept

The perceived global rise in chronic kidney disease (CKD) has been met with apprehension and skepticism. It has been argued by some that we are facing a CKD 'epidemic' and by others that the high prevalence of CKD observed in different communities may be the result of flawed screening methods and tools. Both estimation of glomerular filtration rate and determination of microalbuminuria as markers of CKD have been criticized. Also, many commented that CKD, as currently defined, was primarily a disease of elderly people with reduced kidney function. Some described this as a physiological age-related decline in kidney function while others consider it to be pathological, warranting the label of a disease. In this review, an attempt is made to reconcile different views by examining some of the available evidence and to conclude that the high prevalence of 'CKD' in the elderly population is likely to reflect the underlying high prevalence of overt and subclinical atherosclerosis and cardiovascular disease. This leads to the conclusion that CKD is a reflection of diffuse and age-related Cardio-Kidney-Damage (C-K-D) that may not warrant the label of disease but certainly justifies attention with reduction of lifelong cardiovascular risks and careful evaluation and treatment.

Albuminuria is strongly associated with arterial stiffness, especially in diabetic or hypertensive subjects--a population-based study (Taichung Community Health Study, TCHS)

OBJECTIVE

Albuminuria is recognized as a marker of vascular dysfunction. Brachial-ankle pulse wave velocity (baPWV) reflects the stiffness of central and peripheral muscular arteries. Limited information is available for the association between albuminuria and arterial stiffness in Chinese. We aimed to assess the association between albuminuria and arterial stiffness in a middle-aged population-based study.

METHODS

A total of 2180 subjects aged 40 years and over were recruited in 2004 in Taiwan. Albuminuria was defined as urinary albumin-to-creatinine ratio (ACR)>or=30 mg/g creatinine. BaPWV was divided by quartile. Multiple logistic and linear regression analyses were used to evaluate the relationship between baPWV and albuminuria.

RESULTS

After adjusting for age, body mass index, mean arterial pressure, fasting glucose, triglycerides, total cholesterol, chronic kidney disease, smoking, alcohol drinking, and physical activity status, multiple logistic regression analyses revealed baPWV groups were significantly associated with albuminuria. Compared to the lowest baPWV quartile, the adjusted odds ratio of having albuminuria for baPWV quartile II, III, and IV were 1.12(0.63-2.02), 2.04(1.15-3.60), and 2.45(1.29-4.65). The significant increase in odds ratios for albuminuria in progressive baPWV quartiles reveals a dose-response effect (p<0.001). Among diabetic, hypertensive, and macroalbuminuria subjects, these relationships were stronger than in subjects without diabetes, hypertension, and microalbuminuria. Moreover, multiple linear regression analyses showed that baPWV was significantly associated with urinary ACR after adjusting for potential confounders.

CONCLUSION

Albuminuria was strongly related to arterial stiffness among Chinese middle-aged adults. These relationships were enhanced in subjects with hypertension, diabetes, or macroalbuminuria.

Serum albumin levels predict vascular dysfunction with paradoxical pathogenesis in healthy individuals

BACKGROUND

Serum albumin is affected by both nutritional status and inflammation. It is, therefore, thought to be highly linked with pathogenesis of vascular dysfunction.

METHODS

Cross-sectional data from 2091 individuals aged 23-87, who underwent a general health examination, were analyzed. First, we investigated the association between serum albumin level and vascular functions, as assessed by brachial-ankle pulse-wave velocity (PWV). Then, we evaluated the prevalence of hyperglycemia (fasting blood sugar >or=100mg/dl), metabolic syndrome as determined by NCEP criteria, and inflammation (CRP >or=0.4mg/dl), across tertiles of albumin levels.

RESULTS

In a multivariate regression model, a U-shaped relationship between serum albumin and PWV was statistically significant when albumin level was treated as a continuous variable in g/dl and centered at 4.4g/dl (quadratic term P-value=0.006). The highest tertile of albumin level (4.6-5.4g/dl) was associated with increased odds ratios for hyperglycemia of 1.35 (1.07-1.70) compared to the middle tertile (4.4-4.5g/dl), whereas the lowest tertile (3.3-4.3g/dl) was associated with reduced odds ratios for hyperglycemia of 0.80 (0.65-0.99). The highest tertile was also associated with increased odds ratios for metabolic syndrome of 1.30 (0.96-1.76) compared to the middle tertile, whereas the lowest tertile was associated with reduced odds ratios of 0.70 (0.51-0.95). Furthermore, the lowest tertile was associated with increased prevalence of inflammation with an adjusted odds ratio of 1.85 (1.15-2.97).

CONCLUSIONS

The current results demonstrate that extremes of serum albumin levels are linked to vascular dysfunction among healthy individuals. Furthermore, serum albumin is paradoxically linked to vascular disease under conditions both of overnutrition and of malnutrition and inflammation complex.

Effects of angiotensin II type 1 receptor blocker on ambulatory blood pressure variability in hypertensive patients with overt diabetic nephropathy

Previous studies have shown increases in ambulatory short-term blood pressure (BP) variability to be related to cardiovascular disease. In this study, we examined whether the angiotensin II type 1 receptor blocker (ARB) would improve ambulatory short-term BP variability in hypertensive patients with diabetic nephropathy. A total of 30 patients with type II diabetes, along with hypertension and overt nephropathy, were enrolled in this randomized, two-period, crossover trial of 12 weeks of treatment with losartan (50 mg daily) and telmisartan (40 mg daily). At baseline and at the end of each treatment period, 24-h ambulatory BP monitoring with power spectral analysis of heart rate and measurements of proteinuria, estimated glomerular filtration rate and brachial-ankle pulse wave velocity (baPWV) were performed. After 12 weeks of treatment, 24-h, daytime and nighttime short-term BP variability, assessed on the basis of the coefficient of variation of ambulatory BP, was significantly decreased by telmisartan. Both losartan and telmisartan reduced urinary protein excretion and baPWV. However, compared with losartan, telmisartan significantly decreased urinary protein excretion, baPWV and low-frequency (LF)-to-high-frequency (HF) ratio, an index of sympathovagal balance. Multiple regression analysis showed significant correlations between urinary protein excretion and baPWV, 24-h LF-to-HF ratio, nighttime systolic BP and 24-h short-term systolic BP variability. These results suggest that ARB, particularly telmisartan, is effective in reducing proteinuria in hypertensive patients with overt diabetic nephropathy, partly through inhibitory effects on ambulatory short-term BP variability and sympathetic nerve activity, in addition to its longer duration of action on nighttime BP reduction.

Some mechanical aspects of arterial aging: physiological overview based on pulse wave analysis

Aging has a striking impact on the arterial structure and function. The principal structural change with age is medial degeneration that leads to a progressive stiffening of the large elastic arteries. Large artery stiffening increases aortic systolic and pulse pressures through an increase in the forward incident wave and an early return of the backward reflected wave. Peripheral muscular arteries/arterioles are only minimally affected in structure by aging itself, but impaired vasomotor function can alter their impedance properties and thereby increase reflection magnitude. An augmented aortic pressure due to enhanced wave reflection increases wasted left ventricular effort and causes cardiac hypertrophy. Increased pulsatile pressure and flow stresses extend to the vulnerable microcirculation of vasodilated organs such as the brain and kidneys, and can predispose to cerebral lacunar infarction and albuminuria. Although most currently available vasodilators appear to have little direct effect on degenerated elastic arteries, they can act instead on less-degenerated muscular arteries to markedly reduce peripheral wave reflection magnitude and central aortic pressure, and thus contribute to the regression of left ventricular hypertrophy. Further studies are necessary to examine whether the effect of vasodilator therapy on reducing wave reflection contributes similarly to the prevention of microvascular damage in the brain and kidneys.

Large artery stiffening as a link between cerebral lacunar infarction and renal albuminuria

BACKGROUND

Stiffening of large arteries increases pulsatile pressure and flow stresses, which extend to the microcirculation in vasodilated organs such as the brain and kidneys. Subclinical cerebral lacunar infarction and albuminuria, both of which are early manifestations of microvascular damage, have been shown to be potentially interrelated in hypertension and with aging, but the underlying pathogenesis remains unknown.

METHODS

In a population of 351 general adults aged > or =50 years, urinary albumin/creatinine ratio (ACR), pulse wave velocity (PWV), and 24-h ambulatory blood pressure (BP) were measured, and cerebral lacunar lesions were assessed on magnetic resonance imaging (MRI).

RESULTS

Lacunar infarction was present in 86 subjects (25%). Subjects with lacunae had a higher median urinary ACR than those without (20.6 vs. 14.6 mg/g.Cr, P = 0.004). The positive association between the presence of lacunae and urinary ACR remained significant in a logistic model that adjusted for covariates including age, gender, and 24-h BP (P = 0.04); the odds ratio (OR) for lacunae was 1.32 for each 1 s.d. increase in urinary ACR. However, when PWV was added to this model, increased PWV but not urinary ACR was associated with lacunae. There was a significant interaction between urinary ACR and PWV with respect to lacunae; only subjects with a high PWV above the median showed an independent association between urinary ACR and the presence of lacunae (P = 0.03).

CONCLUSIONS

Microvascular damage in the brain (lacunar infarction) and kidney (albuminuria) appears to be interrelated in the general population. Large arterial stiffening may play a pivotal role in this cerebro-renal connection.