Correlation Between the Cardio-Ankle Vascular Index and Renal Resistive Index in Patients With Essential Hypertension

Relationship of Serum Uric Acid with Kidney Function Decline Mediated by Systemic Arterial Stiffness: A Retrospective Cohort Study in Japan

Hyperuricemia is associated with kidney function decline (KFD), although whether hyperuricemia directly causes nephrotoxicity or is indirectly mediated by systemic arterial stiffening remains unclear. We examined the detailed relationship of serum uric acid (SUA) with KFD and potential mediation by arterial stiffness. Study population was 27,648 urban residents with an estimated glomerular filtration rate (eGFR) of ≥60 mL/min/1.73 m2 at baseline, and they participated in a median of three consecutive annual health examinations. Arterial stiffness was assessed using cardio-ankle vascular index (CAVI). KFD was defined as a decrease in eGFR to below 60. Multivariate analysis showed an association between baseline SUA and CAVI independent of eGFR. During the study period, 6.6% of participants developed KFD. Stratified analysis revealed a linear relationship between the contribution of CAVI or SUA and KFD. ROC analysis determined a cutoff CAVI of 8.0 (males) or 7.9 (females) and a cutoff SUA of 6.3 (males) or 4.5 mg/dL (females) for predicting KFD. The linkage between SUA and CAVI was associated with a greater increase in the hazard ratio for KFD with an increase in SUA. CAVI showed the mediating effect on the relationship of SUA with KFD after an adjustment for confounders. SUA was associated positively with CAVI-mediated KFD. Further studies should verify whether intensive SUA-lowering treatment prevents KFD via improving vascular function.

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

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

Cardio-ankle vascular index with renal progression and mortality in high atherosclerosis risk: a prospective cohort study in CORE-Thailand

BACKGROUND

Increased arterial stiffness is linked to markers of endothelial dysfunction and vasculopathy such as albuminuria, vascular calcification, left ventricular hypertrophy and cardiovascular (CV) diseases. Studies of arterial stiffness on renal progression are limited.

OBJECTIVE

The study aimed to evaluate the association between high cardio-ankle vascular index (CAVI) and renal endpoint and all-cause mortality in a Thai population with high atherosclerosis risk.

METHODS

A multicenter prospective cohort study was conducted among subjects with high CV risk or established CV diseases in Thailand. Subjects were divided into 3 groups with mean CAVI < 8, 8-8.9, and ≥ 9, respectively. Primary composite outcome consisted of estimated glomerular filtration rate (eGFR) decline over 40%, eGFR less than 15 mL/min/1.73 m², doubling of serum creatinine, initiation of dialysis and death related to renal causes. The secondary outcomes were all-cause mortality, CV mortality and eGFR decline.

RESULTS

A total of 4898 subjects (2743 men and 2155 women) were enrolled. Cox proportional hazards model showed a significant relationship of high CAVI (CAVI ≥ 9) and primary composite outcome. Subjects with high CAVI at baseline had a 1.45-fold (95% CI 1.13-1.84) significant risk for the primary composite outcome and 1.72-fold (95% CI 1.12-2.63) risk for all-cause mortality, compared with normal CAVI (CAVI < 8). After stepwise multivariate analysis, the high CAVI group was only positively associated with primary composite outcome. Kaplan-Meier curve of the primary composite outcome and all-cause mortality demonstrated the worst survival in the high CAVI group (log-rank test with P < 0.05).

CONCLUSION

In a Thai cohort with high atherosclerosis risk, increased arterial stiffness was a risk factor for worsening renal function, including end-stage renal disease and initiation of dialysis.

Assessment of Arterial Stiffness Using the Cardio-Ankle Vascular Index – What We Know and What We Strive for

Currently, the importance of assessing arterial stiffness as an integral indicator of cardiovascular risk, an indicator of arteriosclerosis, and a predictor of cardiovascular events has been demonstrated. The traditional indicator of arterial stiffness-pulse wave velocity-depends on the level of blood pressure, which makes it difficult to use it for dynamic assessment. The proposed new arterial stiffness index-the cardio-ankle vascular index (CAVI), does not depend on the level of blood pressure and is more convenient in practical use. CAVI has been widely used in clinical medicine for the past 15 years as an index for assessing cardiovascular diseases and risk factors, which has allowed for the expansion and deepening of research on this topic. This review focuses primarily on recent publications and new opportunities for evaluating vascular function using CAVI. The review provides information on solving methodological problems in evaluating CAVI, highlights the relationship between CAVI and future cardiovascular events, and provides cross-sectional data on the Association of CAVI with the presence of cardiovascular diseases and their risk factors. The results of studies on the effect of drug therapy and measures to control risk factors for cardiovascular diseases on CAVI are presented. While it remains unclear how much changes in CAVI over time can affect the forecast, research is currently being conducted in this direction. The use of CAVI also opens up new perspectives in the assessment of cardiovascular interactions, the study of vascular function in vasculitis and vascular injuries, as well as in geriatric medicine (concepts of premature vascular aging and excess vascular aging).

Clinical Significance of the Cardio-Ankle Vascular Index in Postmenopausal Women With Hypercholesterolemia

Background

The cardio-ankle vascular index (CAVI) is a physiological indicator of arterial elasticity. However, limited information regarding the clinical significance of the CAVI in patients with hypercholesterolemia is available. This cross-sectional study aimed to elucidate the clinical significance of the CAVI for the primary prevention of cardiovascular disease (CVD) among postmenopausal women with hypercholesterolemia.

Methods

A total of 168 untreated postmenopausal hypercholesterolemic women (low-density lipoprotein cholesterol levels ≥ 140 mg/dL, mean age ± standard deviation, 63 ± 10 years) with no history of CVD events were enrolled. The CAVI was measured using commercial devices, after which, its relationships with various clinical parameters, such as carotid artery ultrasonography findings and CVD biomarkers, were examined.

Results

A significant positive correlation was observed between the CAVI and maximum intima-media thickness of the common carotid artery (max-C-IMT), which was evaluated using carotid artery ultrasonography (r = 0.49, P < 0.001). Regarding CVD biomarkers, the CAVI was significantly correlated with estimated glomerular filtration rate (r = -0.18, P < 0.001), high-sensitivity C-reactive protein (r = 0.36, P < 0.001), whole blood passage time as a marker of blood rheology (r = 0.41, P < 0.001), and skin autofluorescence as a marker of advanced glycation end products in tissues (r = 0.46, P < 0.001), although no significant correlation was noted between serum lipid parameters and the CAVI. Multiple regression analysis identified max-C-IMT (β = 0.35, P < 0.001), whole blood passage time (β = 0.18, P = 0.007), skin autofluorescence (β = 0.17, P = 0.011), and age (β = 0.16, P = 0.018) as variables independently associated with CAVI.

Conclusion

The present study indicated that the CAVI is an essential CVD risk factor among postmenopausal women with hypercholesterolemia. Moreover, impaired blood rheology and increase of skin autofluorescence were associated with elevated CAVI in such patients.