Cardio-ankle vascular index to screen cardiovascular diseases in patients with end-stage renal diseases

Pilot study to investigate differences in middle molecules, oxidative stress and markers of peripheral vascular disease in patients treated by high flux haemodialysis and haemodiafiltration

Background

Dialysis patients have an increased risk of mortality. Recently treatment with haemodiafiltration (HDF) has been reported to reduce mortality, particularly cardiovascular mortality, compared to standard high-flux haemodialysis (HD). However, why HDF may offer a survival advantage remains to be determined. So, we conducted a pilot study to explore differences in middle-molecules, inflammation and markers of vascular disease in patients treated by HD and HDF.

Methods

Observational cross-sectional study measuring serum β2-microglobulin (β2M), Advanced Glycosylation End Products (AGEs) by skin autofluorescence (SAF), oxidative stress with ischaemia modified albumin ratio (IMAR) and peripheral vascular disease assessment using Ankle-Brachial Index (ABI), and arterial stiffness using Cardio-Ankle Vascular Index (CAVI).

Results

We studied 196 patients, mean age 69.1 ± 12.4 years, 172 (87.8%) treated by HD and 24 (12.2%) by HDF. Age, body mass index, co-morbidity and dialysis vintage were not different between HD and HDF groups. Middle molecules; β₂M (31±9.9 vs 31.2±10 ug/mL) and SAF (2.99±0.72 vs 3.0±0.84 AU), ABI (1.06±0.05 vs 1.07±0.10) and CAVI (9.34±1.55 vs 9.35±1.23) were not different, but IMAR was higher in the HD patients (38.4±14.8 vs 31.3 ± 17.4, P = 0.035)

Conclusions

In this pilot observational study, we found patients treated by HDF had lower oxidative stress as measured by IMAR, with no differences in middle molecules. Lower oxidative stress would be expected to have diverse protective effects on the cardiovascular system Although we found no differences in ABI and CAVI, future studies are required to determine whether reduced oxidative stress translates into clinically relevant differences over time.

Association of the Estimated Coronary Artery Incidence Risk According to the Japan Atherosclerosis Society Guidelines 2017 with Cardio-Ankle Vascular Index

Aims: The categories in the comprehensive lipid and risk management guidelines were proposed by the Japan Atherosclerosis Society (JAS Guidelines 2017), which adopted the estimated 10 year absolute risk of coronary artery disease (CAD) incidence in the Suita score. We examined whether those categories were concordant with the degree of arterial stiffness.

Methods: In 2014, the cardio-ankle vascular index (CAVI), an arterial stiffness parameter, was measured in 1,972 Japanese participants aged 35–74 years in Tsuruoka City, Yamagata Prefecture, Japan. We examined the mean CAVI and the proportion and odds ratios (ORs) of CAVI ≥ 9.0 on the basis of the following three management classifications using the analysis of variance and logistic regression: “Category I (Low risk),” “Category II (Middle risk),” and “Category III (High risk).”

Results: The mean CAVI and proportion of CAVI ≥ 9.0 were 8.6 and 34.8% among males and 8.1 and 18.3% among females, respectively. The mean CAVI and proportion of CAVI ≥ 9.0 were associated with an estimated 10 year absolute risk for CAD among males and females, excluding High risk for females. These results were similar to the management classification by the guideline: the multivariable-adjusted ORs (95% confidence intervals) of CAVI ≥ 9.0 among Category II and Category III compared with those among Category I were 2.96 (1.61–5.43) and 7.33 (4.03–13.3) for males and 3.99 (2.55–6.24) and 3.34 (2.16–5.16) for females, respectively.

Conclusions: The risk stratification, which was proposed in the JAS Guidelines 2017, is concordant with the arterial stiffness parameter.

New Horizons of Arterial Stiffness Developed Using Cardio-Ankle Vascular Index (CAVI)

Arterial stiffness is recognized mainly as an indicator of arteriosclerosis and a predictor of cardiovascular events. Cardio-ankle vascular index (CAVI), which reflects arterial stiffness from the origin of the aorta to the ankle, was developed in 2004. An important feature of this index is the independency from blood pressure at the time of measurement. A large volume of clinical evidence obtained using CAVI has been reported. CAVI is high in patients with various atherosclerotic diseases including coronary artery disease and chronic kidney disease. Most coronary risk factors increase CAVI and their improvement reduces CAVI. Many prospective studies have investigated the association between CAVI and future cardiovascular disease (CVD), and proposed CAVI of 9 as the optimal cut-off value for predicting CVD. Research also shows that CAVI reflects afterload and left ventricular diastolic dysfunction in patients with heart failure. Furthermore, relatively acute changes in CAVI are observed under various pathophysiological conditions including mental stress, septic shock and congestive heart failure, and in pharmacological studies. CAVI seems to reflect not only structural stiffness but also functional stiffness involved in acute vascular functions. In 2016, Spronck and colleagues proposed a variant index CAVI₀, and claimed that CAVI₀ was truly independent of blood pressure while CAVI was not. This argument was settled, and the independence of CAVI from blood pressure was reaffirmed. In this review, we summarize the recently accumulated evidence of CAVI, focusing on the proposed cut-off values for CVD events, and suggest the development of new horizons of vascular function index using CAVI.

Arterial stiffness in young women with Turner syndrome using cardio-ankle vascular index

PURPOSE

Patients with Turner syndrome (TS) have increased risk of morbidities and mortality related to cardiovascular complications. Cardio-ankle vascular index (CAVI) is a novel method of evaluating arterial stiffness independent of changes in blood pressure. We compared arterial stiffness using CAVI between TS patients and healthy control subjects.

METHODS

Nineteen young women with TS (mean, 26.8 years; range, 20.0-35.1 years) and 23 healthy women matched for age and body mass index (BMI) were recruited for CAVI measurements at Seoul National University Hospital between 2010 and 2013. Anthropometric parameters, fasting blood testing and measurements of CAVI were compared between the 2 groups.

RESULTS

TS patients were significantly shorter (mean: 150.1 cm vs. 160.7 cm, P<0.001) and had lower body weight (mean: 47.0 kg vs. 55.5 kg, P=0.014) than healthy controls, without difference in BMI. CAVI (6.5±0.6 vs. 6.1±0.6, P=0.039) was significantly higher in TS patients compared to healthy controls. Age was positively associated with CAVI (r=0.403, P=0.008) in univariate analysis. After adjusting for age, TS was associated with CAVI (P=0.006).

CONCLUSION

Young women with TS showed increased arterial stiffness measured by CAVI compared to healthy women after adjusting for age, suggesting inherent vasculopathy in TS patients.

Cardio-Ankle Vascular Index as a Surrogate Marker of Early Atherosclerotic Cardiovascular Disease in Koreans with Type 2 Diabetes Mellitus

BACKGROUND

Carotid artery intima medial thickness (IMT), brachial-ankle pulse wave velocity (baPWV), and ankle-brachial index (ABI) are commonly used surrogate markers of subclinical atherosclerosis in patients with type 2 diabetes mellitus (T2DM). The cardio-ankle vascular index (CAVI) is a complement to the baPWV, which is affected by blood pressure. However, it is unclear which marker is the most sensitive predictor of atherosclerotic cardiovascular disease (ASCVD).

METHODS

This was a retrospective non-interventional study that enrolled 219 patients with T2DM. The correlations among IMT, ABI, and CAVI as well as the relationship of these tests to the 10-year ASCVD risk were also analyzed.

RESULTS

Among the 219 patients, 39 (17.8%) had ASCVD. In the non-ASCVD group, CAVI correlated significantly with IMT after adjusting for confounding variables, but ABI was not associated with CAVI or IMT. The analyses after dividing the non-ASCVD group into three subgroups according to the CAVI score (<8, ≥8 and <9, and ≥9) demonstrated the significant increase in the mean IMT, 10-year ASCVD risk and number of metabolic syndrome risk factors, and decrease in the mean ABI in the high-CAVI group. A high CAVI was an independent risk factor in the non-ASCVD group for both a high 10-year ASCVD risk (≥7.5%; odds ratio [OR], 2.42; P<0.001) and atherosclerosis (mean IMT ≥1 mm; OR, 1.53; P=0.007).

CONCLUSION

In Korean patients with T2DM without ASCVD, CAVI was the most sensitive of several surrogate markers for the detection of subclinical atherosclerosis.

Effect of Sodium Thiosulfate on Arterial Stiffness in End-Stage Renal Disease Patients Undergoing Chronic Hemodialysis (Sodium Thiosulfate-Hemodialysis Study): A Randomized Controlled Trial

BACKGROUND

Arterial stiffness (AS) and vascular calcification are significantly related to a high cardiovascular mortality risk in hemodialysis (HD) patients. Intravenous sodium thiosulfate (IV STS) can prevent and delay the vascular calcification progression in uremic states; however, the STS effect on AS has not been assessed. This study aimed to evaluate the STS efficacy on vascular calcification and AS in HD patients.

METHODS

Fifty HD patients with abnormal AS, as measured via the cardio-ankle vascular index (CAVI ≥8), were prospectively randomized to open-label 12.5 g IV STS during the last HD hour twice weekly for 6 months (n = 24) or the usual care (control group; n = 26). Patients and treating physicians were not blinded. The CAVI, coronary artery calcification (CAC) score, hemodynamics, and biochemical parameters were measured at the baseline and at 3 and 6 months.

RESULTS

All the baseline parameters were comparable. The IV STS significantly reduced the CAVI when compared to the control group (mean CAVI difference = -0.53; 95% CI -1.00 to -0.06; p = 0.03). A significant CAVI improvement was seen in those patients without diabetes mellitus. The natural logarithm of the CAC volume score was significantly increased in the control group. The high sensitivity C-reactive protein level was slightly lowered in the IV STS group (not significant).

CONCLUSION

The intradialytic STS treatment significantly reduced the AS, as measured by the CAVI, and stabilized the vascular calcification in the HD patients. STS may be a novel therapeutic strategy for delaying and treating the structural and functional vascular wall abnormalities in HD patients.

Aortic-Brachial Pulse Wave Velocity Ratio: A Measure of Arterial Stiffness Gradient Not Affected by Mean Arterial Pressure

Background

Aortic stiffness, measured by carotid-femoral pulse wave velocity (cf-PWV), is used for the prediction of cardiovascular risk. This mini-review describes the nonlinear relationship between cf-PWV and operational blood pressure, presents the proposed methods to adjust for this relationship, and discusses a potential place for aortic-brachial PWV ratio (a measure of arterial stiffness gradient) as a blood pressure-independent measure of vascular aging.

Summary

PWV is inherently dependent on the operational blood pressure. In cross-sectional studies, PWV adjustment for mean arterial pressure (MAP) is preferred, but still remains a nonoptimal approach, as the relationship between PWV and blood pressure is nonlinear and varies considerably among individuals due to heterogeneity in genetic background, vascular tone, and vascular remodeling. Extrapolations from the blood pressure-independent stiffness parameter β (β₀) have led to the creation of stiffness index β, which can be used for local stiffness. A similar approach has been used for cardio-ankle PWV to generate a blood pressure-independent cardio-ankle vascular index (CAVI). It was recently demonstrated that stiffness index β and CAVI remain slightly blood pressure-dependent, and a more appropriate formula has been proposed to make the proper adjustments. On the other hand, the negative impact of aortic stiffness on clinical outcomes is thought to be mediated through attenuation or reversal of the arterial stiffness gradient, which can also be influenced by a reduction in peripheral medium-sized muscular arteries in conditions that predispose to accelerate vascular aging. Arterial stiffness gradient, assessed by aortic-brachial PWV ratio, is emerging to be at least as good as cf-PWV for risk prediction, but has the advantage of not being affected by operating MAP.

Key Messages

The negative impacts of aortic stiffness on clinical outcomes are proposed to be mediated through attenuation or reversal of arterial stiffness gradient. Aortic-brachial PWV ratio, a measure of arterial stiffness gradient, is independent of MAP.

Arterial Stiffening and Clinical Outcomes in Dialysis Patients

Cardiovascular disease (CVD) is an important cause of morbidity and mortality in dialysis patients. Brachial-ankle pulse wave velocity (baPWV) is more efficient to handily assess arteriosclerosis than aortic PWV. The cardio-ankle vascular index (CAVI) is also a novel blood pressure-independent arterial stiffness parameter. In dialysis patients, both baPWV and CAVI are increased compared to general subjects. Several studies have demonstrated that increased baPWV is associated with carotid atherosclerosis and diastolic left ventricular dysfunction in hemodialysis (HD) patients. In addition, higher baPWV is related to all-cause and cardiovascular (CV) mortality. CAVI is similarly associated with CVD. However, baPWV is superior to CAVI as a predictor of CV outcomes in HD patients. Besides these outcomes, a close relationship exists between sarcopenia, abdominal visceral obesity and arterial stiffening. Reduction of thigh muscle mass is inversely correlated with baPWV and CAVI in males. Abdominal fatness is also associated with increased arterial stiffness in females. These observations provide further evidence of higher risk of CV events in HD patients with sarcopenic obesity. In addition, arterial stiffness is associated with cerebral small vessel disease and decreased cognitive function in the elderly. However, it is unknown whether arterial stiffness may be useful as an early indicator of cognitive decline in dialysis patients. Because dialysis patients are at risk of developing dementia, more studies are needed to elucidate the causal link between arterial stiffness and cognitive impairment.

Skin autofluorescence is a predictor of cardiovascular disease in chronic kidney disease patients

Accelerated formation and tissue accumulation of advanced glycation end products (AGEs), reflecting cumulative glycemic and oxidative stress, occurs in age-related and chronic diseases like diabetes mellitus (DM) and renal failure, and contributes to vascular damage. Skin autofluorescence (AFR), a noninvasive measurement method, reflects tissue accumulation of AGEs. AFR has been reported to be an independent predictor of mortality in Caucasian hemodialysis patients. We assessed the relationship between levels of AFR and the prevalence of cardiovascular disease (CVD), and clarified the prognostic usefulness of skin AFR levels in Asian (non-Caucasian) hemodialysis (HD) patients. AFR was measured with an autofluorescence reader in 64 HD patients. Overall and cardiovascular mortality was monitored prospectively during the 3-year follow-up. During follow-up, CVD events occurred in 21 patients. The deaths of 10 HD patients were associated with CVD. Multivariate logistic regression analyses showed that initial AFR was an independent risk factor for de novo CVD in HD patients with or without diabetes. When patients were classified on the basis of AFR tertiles, Cochran-Armitage analysis demonstrated that the highest tertile of AFR level showed an increased odds ratio for the prevalence of CVD. These findings suggest that AFR levels can be used to detect the prevalence of CVD in HD patients with or without diabetes.

Paradoxical Distribution of Augmentation Index Level in Chronic Kidney Diseases

Pulse wave velocity (PWV) and augmentation index (AI) are used as indexes of arterial stiffness and cardiovascular survival. Although PWV is known to increase as the stage of chronic kidney disease (CKD) advances, how this is related to AI and CKD stage has not yet been well defined.

A sub-analysis was performed using the data from the Antihypertensive and Blood Pressure of Central Artery in Japan study. This was a cross-sectional study on hypertensive patients. All the patients with available serum creatinine levels were selected, and estimated glomerular filtration rate (eGFR) was calculated according to the modification of diet in renal disease equation for a Japanese population. Augmentation indexes at different stages of CKD were compared.

Data from 1392 patients were pooled and analyzed. In addition to eGFR, there were differences in age (P<0.0001), pulse rate (P<0.0001), vasodilator antihypertensive drugs (P<0.005), systolic (P<0.005) and diastolic (P<0.01) blood pressure at 5 CKD stages. Multivariate regression showed that AI correlated to age (0.19%/year), pulse rate (-0.54%/bpm), systolic blood pressure (0.18%/mmHg) and vasodilator antihypertensive drugs (-2.42%/class). Therefore, AI was adjusted for these confounding factors. Adjusted AI in stage 5 (77±20%) was lower than that in stage 1 (84±19%, P<0.05).

These data indicate that AI varies according to CKD stage, and suggest that a cut-off value of AI should be set for each stage of CKD to detect cardiovascular disease.

Neutrophil gelatinase-associated lipocalin levels associated with cardiovascular disease in chronic kidney disease patients

BACKGROUND

Elevated levels of neutrophil gelatinase-associated lipocalin (NGAL) have been reported in patients with cardiovascular disease (CVD), heart failure, and stroke. We assessed the relationships between serum levels of NGAL and the prevalence of CVD, and clarified the prognostic usefulness of systemic NGAL levels in hemodialysis (HD) patients.

METHODS

Eighty-eight HD patients were followed up for 1 year. Logistic regression analyses were used to investigate the relationship between de novo CVD status and NGAL levels as well as other risk factors.

RESULTS

During follow-up, CVD events occurred in 20 patients. Initial serum levels of NGAL and brain natriuretic peptide of HD patients with de novo CVD were significantly higher than those of HD patients without de novo CVD. Multivariate logistic regression analyses showed that initial serum levels of NGAL were independent risk factors for de novo CVD in HD patients. When patients were classified on the basis of NGAL quartiles, multiple logistic regression analyses demonstrated that the highest quartile of NGAL level showed an increased odds ratio for the prevalence of CVD.

CONCLUSION

These findings suggest that NGAL levels can be used to detect the prevalence of CVD in HD patients with or without diabetes.

Cardio-ankle vascular index (CAVI) as an indicator of arterial stiffness

Arterial stiffness has been identified as an independent predictor of prognostic outcomes for patients with cardiovascular disease. Although measurement of pulse wave velocity has been a widely accepted noninvasive approach to the assessment of arterial stiffness, its accuracy is hampered by changes in blood pressure. Taking the exponential relation between intravascular pressure and arterial diameter into consideration, a stiffness parameter can be obtained by plotting the natural logarithm of systolic–diastolic pressure ratio against the arterial wall extensibility. Cardio-ankle vascular index (CAVI), which is calculated based on the stiffness parameter thus obtained, is theoretically independent of changes in blood pressure. With this distinct advantage, CAVI has been widely applied clinically to assess arterial stiffness in subjects with known cardiovascular diseases including those with diagnosed atherosclerosis, coronary heart disease, and stroke as well as those at risk, including those with hypertension, diabetes, the elderly, and the obese. Because of its enhanced sensitivity, not only has the index been used to discern subtle changes in the disease process, it has also been utilized in studying normal individuals to assess their potential risks of developing cardiovascular diseases. The primary aims of assessing arterial stiffness using CAVI are not only to aid in early detection of arteriosclerosis to allow timely treatment and change in lifestyle, but also to quantitatively evaluate the progression of disease and the effectiveness of treatment. Despite its merit of being unaffected by blood pressure, discretion in data interpretation is suggested because an elevated CAVI represents not just vascular stiffness caused by pathological changes in the arterial wall, but can also be attributed to an increased vascular tone brought about by smooth muscle contraction. Moreover, certain patient populations, such as those with an ankle-brachial index < 0.9, may give falsely low CAVI and are suggested to be excluded from study.

Aliskiren reduces morning blood pressure in hypertensive patients with diabetic nephropathy on hemodialysis

Our previous study indicated that the exchange from an angiotensin receptor blocker (ARB) to aliskiren reduced morning blood pressure and albuminuria in hypertensive patients with diabetic nephropathy. We extended the above study and assessed the effects of exchanging from an ARB to aliskiren on home blood pressure in hypertensive patients with diabetic nephropathy on chronic hemodialysis. The patients who were persistently hypertensive despite antihypertensive therapy, including ARB, were considered as candidates for the exchange from the ARB to aliskiren. Patients' age and durations of diabetes and hemodialysis were averaged as 62 ± 9 years old, 15 ± 8 and 7 ± 3 years, respectively. Aliskiren decreased morning systolic blood pressure (149 ± 14 to 144 ± 13 mm Hg, n = 30, P < .01) and plasma renin activity (3.5 ± 1.1 to 1.2 ± 0.6 ng/mL/h, P < .01) without changes in serum potassium. Aliskiren also reduced interdialytic weight gain (2.7 ± 0.6 to 2.5 ± 0.5 kg/interval, P < .05) and attenuated the magnitude of intradialytic declines in systolic (-20 ± 11 to -17 ± 10 mm Hg, P < .05) and diastolic blood pressure (-9 ± 6 to -5 ± 5 mm Hg, P < .01). The exchange from an ARB to aliskiren is safe and useful to control home blood pressure in hypertensive hemodialysis patients with diabetic nephropathy. Aliskiren reduced both intradialytic blood pressure drops and interdialytic weight gain in patients with DN.

Relation between cardio-ankle vascular index and coronary artery calcification or stenosis in asymptomatic subjects

AIM

The cardio-ankle vascular index (CAVI) is an index of arterial stiffness. We investigated the association of CAVI with the severity of coronary artery calcification (CAC) and coronary stenosis by coronary computed tomography angiography (CTA) in an asymptomatic population.

METHODS

A total of 549 asymptomatic Korean individuals who underwent CAVI and CTA were analyzed retrospectively. CAC and coronary stenosis were measured by CTA and assessed for the correlation with CAVI.

RESULTS

The degree of CAC and coronary stenosis demonstrated a significant correlation with CAVI (r= 0.187, p<0.001 and r= 0.212, p<0.001 for the CAC score and stenosis, respectively). After adjustment for potential confounders, including age, gender, hypertension, diabetes mellitus, and dyslipidemia, a predefined cutoff value of CAVI ≥8 was associated with advanced CAC (CAC ≥300) and significant coronary stenosis (stenosis ≥50%). Specifically, the adjusted odds ratio (95% confidence interval) of CAC ≥300 and coronary stenosis ≥50% was 3.57 (1.92-6.66) and 2.81 (1.13-7.00), respectively. Additional inclusion of CAVI improved the predictive power of the receiver operating characteristic curves for predicting coronary atherosclerosis based on traditional risk factors; the area under the curve for predicting CAC ≥300 and coronary stenosis ≥50% increased from 0.739 to 0.791 (p for difference= 0.023), and from 0.761 to 0.842 (p= 0.032), respectively.

CONCLUSIONS

CAVI reflects coronary atherosclerosis and may be used as a screening tool for assessing subclinical atherosclerotic burden in an asymptomatic population.

Arterial stiffness using cardio-ankle vascular index reflects cerebral small vessel disease in healthy young and middle aged subjects

AIM

The cardio-ankle vascular index (CAVI) reflects overall arterial stiffness from the aorta to the ankle, independent of blood pressure. Cerebral small vessel diseases (SVDs), including white matter lesions (WML), silent lacunar infarction (SLI) and cerebral microbleeds (CMB), are considered to increase the risk of stroke and cognitive impairment further. We aimed to investigate the association of cerebral SVD with CAVI in asymptomatic young and middle-aged subjects.

METHODS

Asymptomatic Korean individuals aged 30 to 59 years old without neurologic disease who had CAVI and brain magnetic resonance imaging (MRI) were evaluated retrospectively.

RESULTS

Among 484 subjects, cerebral SVDs (advanced WML, SLI and CMB) were found in 20 (4.1%). Subjects with SVDs tended to be older and to have higher systolic blood pressure (SBP) and higher CAVI. From multivariate regression analysis, including pulse pressure (PP) or SBP, CAVI showed a significant association with SVD [adjusted OR (95% CI): 1.889 (1.094-3.263), p= 0.002 and 1.793 (1.020-3.153), p= 0.043, for PP and SBP, respectively]. When CAVI was assessed by quartiles, the highest quartile of CAVI (CAVI >7.65) showed a significant association with SVD, after adjustment for PP [adjusted OR (95% CI): 2.766 (1.115-6.866), p= 0.028].

CONCLUSION

In young and middle-aged subjects, cerebral SVD was significantly associated with arterial stiffness measured by CAVI after adjusting for PP or SBP.

Stiffness parameter β as a predictor of the 4-year all-cause mortality of chronic hemodialysis patients

BACKGROUND

There is a lack of information on stiffness parameter β, an index of arterial stiffness, in hemodialysis (HD) patients. The aim of the present study was to investigate whether stiffness parameter β is predictive of the long-term mortality of chronic HD patients.

METHODS

We measured biochemical parameters and the stiffness parameter β of 80 patients on maintenance HD therapy and followed their course for 4 years, and we enrolled 70 of these 80 patients in the study. We divided the 70 patients into tertiles according to their stiffness parameter β values, and conducted multivariate analyses to examine the impact of the tertiles on 4-year mortality.

RESULTS

Older age and the presence of diabetes mellitus were found to be independently associated with higher stiffness parameter β values. Fifteen patients (21.4 %) died and 16 (22.9 %) experienced a new cardiovascular event during the follow-up period. The results of a Kaplan-Meier analysis revealed a significantly higher risk of all-cause mortality in the HD patients with highest stiffness parameter β values (p = 0.0106). According to the ROC curve, the cut-off level that yielded maximal sensitivity and specificity for predicting all-cause mortality was 10.1, and the sensitivity and specificity using the cut-off value were 69.2 and 70.2 %, respectively.

CONCLUSION

The results of this study suggest that stiffness parameter β is a predictor of all-cause mortality in chronic HD patients.

Brachial-ankle pulse wave velocity and the cardio-ankle vascular index as a predictor of cardiovascular outcomes in patients on regular hemodialysis

Brachial-ankle pulse wave velocity (baPWV) and the cardio-ankle vascular index (CAVI) are both used to evaluate arterial stiffness. The aim of the present study is to determine whether baPWV or CAVI is superior as a marker of arterial stiffness in hemodialysis (HD) patients. Of 194 patients, 59 patients had been excluded from the study due to advanced age over 76 years old (n = 29), or abnormal ankle-brachial pressure index (ABI) (<0.90 or ≥1.30) (n = 30). We then followed the 135 patients (age: 60 ± 11 years, time on HD: 110 ± 93 months) for the 63 ± 4 (55-70) months. Thirty-two (23.7%) patients had expired, 22 of them of cardiovascular (CV) causes. There were 37 fatal and non-fatal CV events. Kaplan-Meier analysis revealed that the patients with the highest tertile of baPWV (≥16.6 m/s) had a significantly lower survival rate (P < 0.01) when compared with the second (13.4 ≤ baPWV < 16.6 m/s) and the lowest tertiles (<13.4 m/s). Cox hazards analysis after adjustment for comorbid risk factors revealed that the top tertile of baPWV was a determinant of CV death (hazards ratio [HR]: 16.9 [1.1-251.8], P < 0.05) In contrast, CAVI did not associate with CV mortality or events. These findings suggest that baPWV is superior to CAVI as a predictor of CV outcomes in patients on regular HD.

Acute decrease of cardio-ankle vascular index with the administration of beraprost sodium

AIM

A novel arterial stiffness index, the cardio-ankle vascular index (CAVI), has been proposed. To clarify the properties of CAVI, the effects of beraprost sodium (BPS), a prostaglandin (PG) I2 analogue, which has a potent vasodilating effect, on CAVI were studied and comparing with brachialankle pulse wave velocity (baPWV) in healthy volunteers.

METHODS

Male volunteers (n=18, 46.3±4.2 yr) were enrolled in this study and administered BPS (40 µg). CAVI and baPWV were measured every hour for 4 hours.

RESULTS

When BPS was administered to 18 healthy volunteers, systolic blood pressure and diastolic blood pressure fluctuated slightly, but the means did not change. CAVI significantly decreased in the 1st hour from 8.3±0.34 (mean±SE) to 7.9±0.34 (p<0.05) and this decrease persisted for 3 hours, whereas baPWV did not significantly change. ΔbaPWV each time was significantly correlated with both Δsystolic blood pressure and Δdiastolic blood pressure, but ΔCAVI did not correlate with either Δsystolic blood pressure (r=-0.12, p=0.38) or Δdiastolc blood pressure (r=-0.22, p=0.10).

CONCLUSIONS

Beraprost sodium did not decrease blood pressure, but decreased CAVI, whereas baPWV did not change. These results indicate that CAVI partly reflected the contraction of arterial smooth muscle cells.

Arterial stiffness contributes to coronary artery disease risk prediction beyond the traditional risk score (RAMA-EGAT score)

Objectives

The traditional risk score (RAMA-EGAT) has been shown to be an accurate scoring system for predicting coronary artery disease (CAD). Arterial stiffness measured by the cardio–ankle vascular index (CAVI) is known to be a marker of atherosclerotic burden. A study was undertaken to determine whether CAVI improves the prediction of CAD beyond the RAMA-EGAT score.

Design

Cross-sectional study.

Patients

Patients with a moderate to high risk for CAD by the RAMA-EGAT score were enrolled between November 2005 and March 2006. 64-slice multidetector CT coronary angiography was used to evaluate the coronary artery calcium score and coronary stenosis. Arterial stiffness was assessed by CAVI.

Results

1391 patients of median age 59 years (range 31–88) were enrolled in the study, 635 (45.7%) men and 756 (54.3%) women. Of the 1391 patients, 346 (24.87%) had coronary stenosis. There was a correlation between CAVI and the prevalence of coronary stenosis after adjusting for traditional CAD risk factors (OR 3.29). In addition, adding CAVI into the RAMA-EGAT score (modified RAMA-EGAT score) improved the prediction of CAD incidence, increasing C-statistics from 0.72 to 0.85 and resulting in a net reclassification improvement of 27.7% (p<0.0001).

Conclusion

CAVI is an independent risk predictor for CAD. The addition of CAVI to the RAMA-EGAT score significantly improves the diagnostic yield of CAD.

Values of cardio-ankle vascular index (CAVI) between Amami islands and Kagoshima mainland among health checkup examinees

AIM

To investigate the prevalence and geographical variation of high arterial stiffness in groups from the Amami islands (Amami) and Kagoshima mainland (mainland), Japan, using the cardio-ankle vascular index (CAVI) as a surrogate marker of arterial stiffness.

METHODS

We recruited 4,523 health checkup examinees from Amami and 440 examinees from the mainland, with an age range of 40-69 years. The frequency of high arterial stiffness (CAVI≥9.0) was geographically compared between the regions, and both mean CAVI values were compared with those of the healthy Japanese population with less risk factors for coronary artery disease. Clinical, lifestyle, and regional factors for increased CAVI values were estimated by the multiple linear regression model.

RESULTS

The frequency of high arterial stiffness on Amami was significantly lower than on the mainland. Mean CAVI values on Amami were similar in males and lower in females than in the healthy Japanese population, but those on the mainland were higher for both sexes. Age, systolic blood pressure, triglycerides, fasting blood glucose, and a history of hypertension and diabetes mellitus were positively related to increased CAVI values on Amami. The regional factor of Amami, compared with the mainland, was negatively related to increased CAVI values in both sexes after adjusting for traditional cardiovascular risk factors.

CONCLUSION

CAVI values in Amami residents were significantly lower than in mainland residents, suggesting that environmental or genetic factors might have improved arterial stiffness in the Amami population.

Relationship between cardio-ankle vascular index (CAVI) and coronary artery calcification (CAC) in patients with type 2 diabetes mellitus

Early detection of atherosclerosis is important for patients with type 2 diabetes mellitus because cardiovascular disease (CVD) is a main cause of death in these people. In this study, we investigated the relationship between an arterial stiffness parameter called cardio-ankle vascular index (CAVI) and coronary artery calcification (CAC). We performed a cross-sectional study in 371 type 2 diabetic patients with clinical suspicion of coronary heart disease (CHD). We evaluated the relationships between CAVI and CAC score determined by multislice computed tomography as well as major cardiovascular risk factors, including age, body mass index, hemoglobinA1c and the Framingham CHD risk score. CAVI was correlated with age (r = 0.301, p < 0.0001), uric acid (r = 0.236, p < 0.0001), estimated glomerular filtration rate (r = -0.145, p = 0.0166), CHD risk score (r = 0.327, p < 0.0001) and log (CAC + 1) (r = 0.303, p < 0.0001). The area under the receiver operating characteristic curve for CAVI was higher than that of CHD risk score in predicting CAC >0, CAC >100, CAC >400, or CAC >1000. CAVI is positively correlated with CAC, and is considered to be a useful method to detect CAC.

Influence of blood pressure on cardio-ankle vascular index (CAVI) examined based on percentage change during general anesthesia

Cardio-ankle vascular index (CAVI) and brachial-ankle pulse wave velocity (baPWV) are non-invasive methods for estimating arterial distensibility. The purpose of this study is to evaluate whether CAVI as an index of true arterial stiffness is superior to baPWV based on the percentage change in hemodynamics under general anesthesia. CAVI (segment from heart to ankle), k-CAVI (heart to knee) and baPWV (brachial to ankle) in 30 oral surgery patients were measured to compare the decreased blood pressure (BP) after 10 min of tracheal intubation during general anesthesia with the control BP (after 5 min of rest). General anesthesia was performed under endotracheal intubation through intravenous injection of propofol, fentanyl and vecuronium or rocuronium. In both the elderly (65 years) and middle-aged (<65 years) groups, CAVI and k-CAVI did not change during general anesthesia, whereas baPWV and systolic BP (SBP) showed a statistically significant decrease. Thus, the changes in CAVI (ΔCAVI) and k-CAVI (Δk-CAVI) showed no significant correlations with those of SBP (ΔSBP), whereas the changes in baPWV (ΔbaPWV) were significantly correlated with ΔSBP. ΔCAVI and Δk-CAVI showed no significant differences between the two groups, whereas ΔbaPWV and ΔSBP in the elderly group was much higher than that in the middle-aged group. Measurement of CAVI was not affected by the decrease in BP during general anesthesia. In contrast, baPWV was significantly influenced by changes in BP. These findings suggest that CAVI is a useful index of true arterial stiffness and is superior to baPWV.

Serum fibroblast growth factor-23 levels and progression of aortic arch calcification in non-diabetic patients on chronic hemodialysis

AIM

Vascular calcification is a cause of cardiovascular death in hemodialysis (HD) patients. The aim of the present study was to evaluate the relationship between the progression of aortic arch calcification (AoAC) and serum fibroblast growth factor (FGF)-23.

METHODS

The enrolled study subjects were 127 (83 men and 44 women) HD patients. Calcification of the aortic arch was semiquantitatively estimated with a score (AoACS) on plain chest radiology. Change in AoACS (ΔAoACS) was obtained by subtracting the baseline AoACS value from the follow-up AoACS value. The second assessment was performed from 5 years after the first determination.

RESULTS

The percentage of male gender in non-progressors (58.5%) was lesser than in regressors (60.0%) and progressors (74.6%). In addition, the dialysis duration in regressors (14.1±5.1 years) was shorter than in non-progressors (19.5±7.0 years) and progressors (16.8±7.5 years). Interestingly, the serum FGF-23 level in regressors (39225.5±9247.9 pg/mL) was significantly higher than in non-progressors (12896.5±26323.5 pg/mL) and progressors (14062.4±18456.8 pg/mL). Multi-ple regression analyses showed male gender (β value=0.969, F=5.092, p=0.0192), serum levels of albumin (β value=-1.395, F=4.541, p=0.0296) and log FGF-23 (β value=-0.001, F=7.273, p=0.0115) to be significant independent determinants of ΔAoACS.

CONCLUSION

Changes in AoAC evaluated by using a simple chest radiograph are associated with serum FGF-23 levels. Excess accumulation of FGF-23 in serum may enable to inhibit the calcification process in vessel walls in chronic HD patients.

Effects of metabolic syndrome on cardio-ankle vascular index in middle-aged and elderly Chinese

Metabolic syndrome is characterized by multiple risk factors and is associated with increased risk of diabetes and cardiovascular disease. The rapid change in the lifestyle and food habits of Chinese people has resulted in metabolic syndrome becoming one of the most widespread health challenges in China. Recently, the cardio-ankle vascular index (CAVI) was developed as a new parameter reflecting arterial stiffness and providing an index of vascular status. The purpose of this study was to investigate the effect of metabolic syndrome on CAVI. A total of 222 Chinese subjects aged 50-92 years participated in this study. We measured CAVI and examined blood samples to define metabolic syndrome according to the International Diabetes Federation criteria. CAVI in the subjects with abnormal waist circumference was significantly higher than that obtained in the normal subjects (P < 0.01). In the abnormal high-density lipoprotein cholesterol (HDL-C) group, CAVI was significantly increased (P < 0.01) compared to the normal HDL-C group. CAVI showed a positive correlation with waist circumference and increased significantly with the number of metabolic syndrome components. In conclusion, subjects with metabolic syndrome have a high CAVI that indicated arterial stiffness and is closely associated with an increase in the number of metabolic syndrome risk factors. Elevated abdominal obesity and low HDL-C are the main players affecting arterial stiffness in the middle-aged and elderly Chinese. These findings suggest that interaction of the individual components of metabolic syndrome plays a role in the relationship between metabolic syndrome and arterial stiffness.

Height constitutes an important predictor of mortality in end-stage renal disease

Aim. Height is an important determinant of augmentation index (AI) that anticipates cardiovascular prognosis. There is a scanty of the data whether short height predicts survival in patients with end-stage renal diseases, a high risk population. Methods. Fifty two hypertensive patients with type 2 diabetic nephropathy receiving hemodialysis and 52 patients with nondiabetic nephropathy were enrolled. In addition to AI estimated with radial artery tonometry, classical cardiovascular risk factors were considered. Patients were followed for 2 years to assess cardiovascular prognosis. Results. Cox hazards regression revealed that both smoking and shortness in height independently contributed to total mortality and indicated that smoking as well as the presence of left ventricular hypertrophy predicted cardiovascular mortality. Our findings implicated that high AI, the presence of diabetes, and low high-density lipoprotein cholesterol were significant contributors to cardiovascular events. Conclusions. Our findings provide new evidence that shortness in height independently contributes to total mortality in hemodialysis patients.

Effects of personal exposure to particulate matter and ozone on arterial stiffness and heart rate variability in healthy adults

The effects on heart rate variability (HRV) and arterial stiffness from exposure to ambient particulate matter and ozone have not been studied simultaneously. The aim of this study was to analyze these effects with refined exposure estimates from personal measurements of ozone and size-resolved particulate matter mass concentrations. The authors recruited 17 mail carriers in a panel study in Taipei County, Taiwan, during February-March, 2007, and each subject was followed for 5-6 days. Personal ozone and size-fractionated particulate matter exposures were monitored during working hours while carriers delivered mail outdoors. Cardiovascular effects were evaluated with heart rate variability (HRV) indices and an arterial stiffness index, the cardio-ankle vascular index (CAVI). The authors used linear mixed models to examine the association between personal exposure data and the HRV index and CAVI. They found that an interquartile range increase in personal exposure to ozone and particulate matter of between 1.0 and 2.5 microm was associated with a 4.8% and 2.5% increase in CAVI, respectively, in the single-pollutant models. In contrast, the personal exposure data showed no significant effects on HRV. In 2-pollutant models, personal ozone exposure remained significantly associated with the CAVI measurements. The study results indicate that vascular function may be more sensitive to air pollutants than the autonomic balance.

Changes in cardio-ankle vascular index in smoking cessation

AIM

To investigate the effect of smoking and smoking cessation on cardio-ankle vascular index (CAVI).

METHODS

The subjects were 82 smokers (77 men, 64+/-10 years) and 20 non-smokers (18 men, 61+/-7 years). CAVI was measured every 3 months and CAVI severity was classified into 3 levels. Decreased, unchanged, and increased CAVI severity levels were coded as "improvement," "no change," and "exacerbation," respectively. Smoking status was coded as "success" for complete abstinence, "partial success" for a reduced number of cigarettes, and "failure" for an unchanging number of cigarettes.

RESULTS

Compared with non-smokers, smokers showed a higher CAVI (p<0.05) prior to smoking cessation. Post-cessation, CAVI improved from 9.4 to 8.6 (p<0.01) in "success" cases (n=22), and the significant pre-cessation difference from non-smokers (n=20, CAVI=8.8) disappeared. With regard to the change in CAVI severity of each smoking status, "improvement" occurred in 17%, 24%, and 68% of "failure" (n=35), "partial success" (n=25), and "success" (n=22) groups, respectively, and the "success" group was significantly higher than the other two groups.

CONCLUSION

The study showed that CAVI was increased by smoking, and complete smoking cessation improved CAVI.

Cardio-ankle vascular index is independently associated with the severity of coronary atherosclerosis and left ventricular function in patients with ischemic heart disease

AIM

The cardio-ankle vascular index (CAVI) has been proposed as a new noninvasive marker of arterial stiffness independent of blood pressure. We investigated the association of the CAVI with coronary atherosclerosis and left ventricular (LV) systolic and diastolic function in patients with ischemic heart disease (IHD).

METHODS

A total of 206 consecutive subjects undergoing coronary angiography were enrolled. CAVI measurement and echocardiography were performed simultaneously. Patients having significant coronary stenosis were classified into the IHD group.

RESULTS

CAVI in the IHD group (n=133) was significantly higher than in the non-IHD group(n=73)(9.1+/-1.3 vs. 8.7+/-1.2, p=0.02). In all IHD patients, CAVI was negatively correlated with LV ejection fraction (LVEF)(r=-0.31, p<0.01), LV mass index (r=0.24, p<0.01) and angiographic scores of coronary atherosclerosis. Stepwise regression analysis revealed that CAVI was independently associated with LVEF, along with a history of myocardial infarction, LV mass index, and left atrial diameter in all IHD patients (p<0.01). In the sub-analysis of IHD patients with preserved LVEF, CAVI was correlated with echocardiographic parameters regarding LV diastolic function. Multivariate analysis demonstrated that the increased CAVI was significantly associated with LV diastolic dysfunction in patients with preserved LVEF.

CONCLUSION

CAVI, a new parameter of aortic stiffness, was independently associated with LV systolic and diastolic function as well as coronary artery disease in IHD patients.