The Background of Calculating CAVI: Lesson from the Discrepancy Between CAVI and CAVI0

Ongoing Effects of SARS-CoV-2 Infection on Arterial Stiffness in Healthy Adults

There are limited data on the arterial stiffness changes after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The present study evaluated the changes in arterial stiffness in completely healthy patients who had a SARS-CoV-2 infection using the cardio-ankle vascular index (CAVI). The study included 70 patients with SARS-CoV-2 infection between December 2020 and June 2021. A cardiac evaluation was carried out, including chest X-ray, electrocardiography (ECG), and echocardiography in all patients. Within the 1st month and 7th month CAVI was measured. Mean age was 37.8 ± 10.0 years, and 41/70 were female. Mean height was 168.6 ± 9.5 cm, mean weight 73.2 ± 15.1 kg, and mean body mass index (BMI) of the group was 25.6 ± 4.2, respectively. CAVI results from the right arm were 6.45 ± .95 at 1-month follow-up and 6.68 ± 1.05 at 7 months follow-up (P = .016) and from the left arm were 6.43 ± 1.0 at 1-month follow-up, 6.70 ± 1.05 at 7-month follow-up (P = .005). Our results showed an ongoing injury in the arterial system after healthy SARS-COV-2 patients during 7 months, as represented by CAVI measurements.

Cardio-Ankle Vascular Index and Aging: Differences between CAVI and CAVI0

BACKGROUND

Cardio-ankle vascular index (CAVI) and CAVI0 (a mathematical expression derived from CAVI, supposed to be less dependent on blood pressure), can describe arterial stiffness, considering a wide proportion of the arterial tree. The aim of this study was to examine the relationship between CAVI, CAVI0 and aging, looking at the differences between the two arterial stiffness indexes.

METHODS

A total of 191 patients (68 male, mean age 68.3 ± 14.4 years) referred to the Geriatric Ward and Outpatient Clinic at Verona University Hospital were included and underwent a comprehensive clinical evaluation. CAVI and CAVI0 were obtained for each.

RESULTS

CAVI0 steeply rises in the elderly age strata, widening the gap between CAVI and CAVI0. An inverse relationship is evident between CAVI0 and DBP in older patients, and CAVI0 is shown to be dependent on age, DBP and age-DBP interaction (R2 = 0.508). Age modifies the effect of DBP on CAVI0, but not on CAVI.

CONCLUSIONS

The real new findings of our study are that the association between CAVI0 and diastolic blood pressure (DBP) is modified by age, whereas the association between CAVI and DBP is not modified by age. From a clinical point of view, these are very important findings, as DBP decreases with aging, affecting in elderly populations the reliability of CAVI0, which strictly depends on DBP in the formula to calculate it. To monitor the effect of CV therapies, progression of CV diseases and to evaluate clinical outcomes in elderly populations, we suggest using CAVI and not CAVI0.

Relationship between reduced heart rate variability and increased arterial stiffness evaluated by the cardio-ankle vascular index in people with type 2 diabetes

Objective

Cardiac autonomic neuropathy (CAN) is an independent risk factor for cardiovascular mortality and also is associated with a high risk of lethal arrhythmias and sudden death in people with type 1 or 2 diabetes. Heart rate variability (HRV) is an index of cardiac autonomic function. To investigate the relationship between HRV and arterial stiffness evaluated by the cardio-ankle vascular index (CAVI), a relatively new marker for arterial stiffness and a predictor of cardiovascular disease, in patients with type 2 diabetes.

Materials and methods

We studied consecutive 313 patients with type 2 diabetes in a cross-sectional design. HRV was estimated by the coefficient of variation of 100 R-R intervals (CVR-R) at rest and during deep breathing (DB). The difference in CVR-R was defined as CVR-R during DB minus CVR-R at rest. Arterial stiffness was evaluated by CAVI, which is independent of blood pressure (BP). A CAVI greater than or equal to 9.0 was defined as significant arterial stiffening.

Results

Linear regression analysis showed that CAVI correlated positively with age, duration of diabetes, urinary albumin creatinine ratio (UACR), CVR-R during DB, and the difference in CVR-R and negatively with body mass index (BMI), estimated glomerular filtration rate, and sensory nerve conduction velocity and action potential of the sural nerve. Multivariate analysis found that age, BMI, systolic blood pressure, UACR, and CVR-R during DB were independently associated with arterial stiffness determined by CAVI. The CVR-R at rest and during deep breathing was significantly lower in the patients with arterial stiffness than in those without it.

Conclusion

Low HRV estimated by CVR-R during DB is closely associated with arterial stiffness measured by CAVI in people with type 2 diabetes, suggesting that arterial stiffness associated with CAN may be an independent risk factor for cardiovascular disease in people with type 2 diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-022-00604-y.

Relationship Between Cardio-Ankle Vascular Index And Coronary Artery Calcification In A Population Sample Of Southwestern Siberia

Objective — To examine associations between cardio-ankle vascular index (CAVI) and coronary artery calcium (CAC) score a population sample of southwestern Siberia. Methods — From the sample of 1,620 people the final analysis included 1,316 participants 25 to 64 years of age who were enrolled in an observational cross-sectional study, Epidemiology of Cardiovascular Diseases and Their Risk Factors in the Russian Federation (ESSE-RF). Study participants were split among two groups: Group 1 with CAVI≥9.0 (n=128) and Group 2 with CAVI<9.0 (n=1,188). Prevalence of coronary artery calcification in both groups was analyzed via the Agatston method. We compared main demographic and clinical data between the groups, as well as CAC scores. Results — Elevated CAVI (≥9.0) was present in 9.7% of people included in a population sample from southwestern Siberia, and coronary artery calcification was found in 33.5% of the sample. While similar rates of minimum, mild, moderate and severe CAC score were observed in the participants with elevated and normal CAVI values, CAVI as a continuous variable was statistically significantly associated with moderate and severe CAC scores (OR 1.20, 95% CI 1.06-1.37, p=0.004). CAC score values were higher in individuals at the age of ≥50 years with pathological CAVI values (116±489 vs. 75±425 in normal CAVI, p=0.035), but not in patients under the age of 50 years (64±227 and 85±475, p=0.343). Conclusion — CAVI could possibly be used as a feasible marker before assessing the CAC score in some asymptomatic Caucasian subjects, but identifying the most appropriate methods and participants, whom it could be clearly applicable to, requires further studying.

Cardiovascular deconditioning and impact of artificial gravity during 60-day head-down bed rest—Insights from 4D flow cardiac MRI

Microgravity has deleterious effects on the cardiovascular system. We evaluated some parameters of blood flow and vascular stiffness during 60 days of simulated microgravity in head-down tilt (HDT) bed rest. We also tested the hypothesis that daily exposure to 30 min of artificial gravity (1 g) would mitigate these adaptations. 24 healthy subjects (8 women) were evenly distributed in three groups: continuous artificial gravity, intermittent artificial gravity, or control. 4D flow cardiac MRI was acquired in horizontal position before (−9 days), during (5, 21, and 56 days), and after (+4 days) the HDT period. The false discovery rate was set at 0.05. The results are presented as median (first quartile; third quartile). No group or group × time differences were observed so the groups were combined. At the end of the HDT phase, we reported a decrease in the stroke volume allocated to the lower body (−30% [−35%; −22%]) and the upper body (−20% [−30%; +11%]), but in different proportions, reflected by an increased share of blood flow towards the upper body. The aortic pulse wave velocity increased (+16% [+9%; +25%]), and so did other markers of arterial stiffness (CAVI; CAVI0). In males, the time-averaged wall shear stress decreased (−13% [−17%; −5%]) and the relative residence time increased (+14% [+5%; +21%]), while these changes were not observed among females. Most of these parameters tended to or returned to baseline after 4 days of recovery. The effects of the artificial gravity countermeasure were not visible. We recommend increasing the load factor, the time of exposure, or combining it with physical exercise. The changes in blood flow confirmed the different adaptations occurring in the upper and lower body, with a larger share of blood volume dedicated to the upper body during (simulated) microgravity. The aorta appeared stiffer during the HDT phase, however all the changes remained subclinical and probably the sole consequence of reversible functional changes caused by reduced blood flow. Interestingly, some wall shear stress markers were more stable in females than in males. No permanent cardiovascular adaptations following 60 days of HDT bed rest were observed.

Predictive ability of arterial stiffness parameters for renal function decline: a retrospective cohort study comparing cardio-ankle vascular index, pulse wave velocity and cardio-ankle vascular index 0

OBJECTIVE

The relative usefulness of arterial stiffness parameters on renal function remains controversial. This study aimed to compare the predictive ability of three arterial stiffness parameters at baseline; cardio-ankle vascular index (CAVI), heart-ankle pulse wave velocity (haPWV) and CAVI 0 , a variant of CAVI that theoretically excludes dependence on blood pressure, for renal function decline in Japanese general population.

METHODS

A total of 27 864 Japanese urban residents without renal impairment at baseline who participated in two to eight consecutive (mean 3.5 ± 1.7 times) annual health examinations were studied.

RESULTS

During the study period, 6.6% of participants developed renal function decline (estimated glomerular filtration rate <60 ml/min per 1.73 m 2 ), all of whom had relatively high values in all arterial stiffness parameters. In receiver-operating characteristic curve analysis, the discriminatory power for renal function decline showed a decreasing trend of CAVI to haPWV to CAVI 0 (C-statistic: 0.740 vs. 0.734 vs. 0.726). The cut-offs were CAVI 8.0, haPWV 7.23 and CAVI 0 11.6. In Cox-proportional hazards analysis for increase of each parameter above cut-off or by 1 standard deviation (SD) adjusted for two models of confounders, only CAVI always contributed significantly to renal function decline. Restricted cubic spline regression analysis suggested that CAVI most accurately reflected the risk of renal function decline.

CONCLUSION

Increase in arterial stiffness parameters, especially CAVI, may represent a major modifiable risk factor for renal function decline in the general population. Further research is needed to examine whether CAVI-lowering interventions contribute to the prevention of chronic kidney disease.

Association Between Indoxyl Sulfate and Dialysis Initiation and Cardiac Outcomes in Chronic Kidney Disease Patients

Introduction

Indoxyl sulfate, a protein-bound uremic toxin, has been reported as an atherosclerosis and fibrosis accelerator. This study aimed to determine whether serum indoxyl sulfate is associated with cardiac abnormalities, cardiovascular events, and renal progression to dialysis in patients with chronic kidney disease (CKD).

Methods

The prospective study enrolled 89 patients with CKD stage 3 to 5 patients. Serum biochemistry data and indoxyl sulfate were measured. All patients underwent echocardiographic examination. Global longitudinal strain (GLS) was calculated using two-dimensional speckle tracking. The clinical outcomes including cardiovascular event and dialysis initiation were recorded during a 2-year follow-up.

Results

Patients were divided into 2 groups based on the median value of serum indoxyl sulfate (low and high indoxyl sulfate groups). Kaplan–Meier analysis revealed that patients with higher indoxyl sulfate (≥6.124 mg/L) were significantly associated with renal progression to dialysis (p < 0.001). There was no significant difference in cardiovascular events between 2 groups (p = 0.082). In addition, serum indoxyl sulfate level was independently associated with GLS (r = 0.62; p = 0.01). The risk of cardiovascular events was significantly higher in patients with impaired GLS (>−16%) (p = 0.015).

Conclusion

Serum indoxyl sulfate level was a significant predictor for CKD progression to dialysis and was correlated with GLS, a speckle tracking echocardiography parameter representing early LV systolic dysfunction. Furthermore, GLS was associated with cardiovascular events in CKD patients. Serum indoxyl sulfate measurement may help to identify the high dialysis and cardiovascular risk CKD patients beyond traditional risk factors.

Five years of cardio-ankle vascular index (CAVI) and CAVI0: how close are we to a pressure-independent index of arterial stiffness?

Pulse wave velocity, a common metric of arterial stiffness, is an established predictor for cardiovascular events and mortality. However, its intrinsic pressure-dependency complicates the discrimination of acute and chronic impacts of increased blood pressure on arterial stiffness. Cardio-ankle vascular index (CAVI) represented a significant step towards the development of a pressure-independent arterial stiffness metric. However, some potential limitations of CAVI might render this arterial stiffness metric less pressure-independent than originally thought. For this reason, we later introduced CAVI0. Nevertheless, advantages of one approach over the other are left debated. This review aims to shed light on the pressure (in)dependency of both CAVI and CAVI0. By critically reviewing results from studies reporting both CAVI and CAVI0 and using simple analytical methods, we show that CAVI0 may enhance the pressure-independent assessment of arterial stiffness, especially in the presence of large inter-individual differences in blood pressure.

Protein-Bound Uremic Toxins Lowering Effect of Sevelamer in Pre-Dialysis Chronic Kidney Disease Patients with Hyperphosphatemia: A Randomized Controlled Trial

P-cresyl sulfate and indoxyl sulfate are strongly associated with cardiovascular events and all-cause mortality in chronic kidney disease (CKD). This randomized controlled trial was conducted to compare the effects between sevelamer and calcium carbonate on protein-bound uremic toxins in pre-dialysis CKD patients with hyperphosphatemia. Forty pre-dialysis CKD patients with persistent hyperphosphatemia were randomly assigned to receive either 2400 mg of sevelamer daily or 1500 mg of calcium carbonate daily for 24 weeks. A significant decrease of total serum p-cresyl sulfate was observed in sevelamer therapy compared to calcium carbonate therapy (mean difference between two groups −5.61 mg/L; 95% CI −11.01 to −0.27 mg/L; p = 0.04). There was no significant difference in serum indoxyl sulfate levels (p = 0.36). Sevelamer had effects in terms of lowering fibroblast growth factor 23 (p = 0.01) and low-density lipoprotein cholesterol levels (p = 0.04). Sevelamer showed benefits in terms of retarding CKD progression. Changes in vascular stiffness were not found in this study.

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).

Cardio-Ankle Vascular Index in the Persons with Pre-Diabetes and Diabetes Mellitus in the Population Sample of the Russian Federation

The aim of this study was to evaluate Cardio-Ankle Vascular Index (CAVI) and increased arterial stiffness predictors in patients with carbohydrate metabolism disorders (CMD) in the population sample of Russian Federation. Methods: 1617 patients (age 25–64 years) were enrolled in an observational cross-sectional study Epidemiology of Cardiovascular Diseases and Their Risk Factors in the Regions of the Russian Federation (ESSE-RF). The standard ESSE-RF protocol has been extended to measure the cardio-ankle vascular index (CAVI), a marker of arterial stiffness. Patients were divided into three groups: patients with type 2 diabetes mellitus (n = 272), patients with prediabetes (n = 44), and persons without CMD (n = 1301). Results: Median CAVI was higher in diabetes and prediabetes groups compared with group without CMD (p = 0.009 and p < 0.001, respectively). Elevated CAVI (≥9.0) was detected in 16.8% of diabetes patients, in 15.9% of those with prediabetes, and in 9.0% of those without CMD (p < 0.001). The factors affecting on CAVI did not differ in CVD groups. In logistic regression the visceral obesity, increasing systolic blood pressure (SBP) and decreasing glomerular filtration rate (GFR) were associated with a pathological CAVI in CMD patients, and age, diastolic blood pressure (DBP), and cholesterol in persons without CMD. Conclusions: the CAVI index values in the prediabetes and diabetes patients were higher than in normoglycemic persons in a population sample of the Russian Federation. Since the identified disorders of arterial stiffness in prediabetes are similar to those in diabetes, their identification is important to prevent further cardiovascular complications.