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

Effect of balloon pulmonary angioplasty on cardio-ankle vascular index and biventricular remodeling in patients with chronic thromboembolic pulmonary hypertension

Background

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by organized pulmonary thrombi, and pulmonary endarterectomy is the only curative treatment. Since balloon pulmonary angioplasty (BPA) has become an established therapeutic option for inoperable CTEPH, prognosis has improved. Recent reports suggest that arterial stiffness evaluated using the cardio-ankle vascular index (CAVI) may play an important role in the cardio-vascular interaction in CTEPH; however, the details remain unclear. This study aimed to clarify the role of CAVI in CTEPH through hemodynamic changes and ventricular remodeling after BPA.

Methods and results

A total of 23 patients with CTEPH who had undergone BPA were enrolled in this study. The mean pulmonary artery pressure (mPAP) and CAVI significantly decreased after BPA [mPAP, 34 (26-45) mmHg to 20 (19-24) mmHg, p < 0.0001; CAVI, 9.4 (8.0-10.3) to 8.3 (7.5-9.6), p = 0.004]. The echocardiographic right ventricle was significantly decreased, and the left ventricular volume was significantly increased after BPA, indicating significant biventricular remodeling after BPA. Changes in CAVI (ΔCAVI) significantly correlated with changes in mPAP (r = 0.45, p = 0.03). Additionally, ΔCAVI was significantly correlated with changes in both right ventricular area and left ventricular volume.

Conclusions

Arterial stiffness, evaluated using the CAVI, improved after BPA. Changes in CAVI were significantly correlated with changes in pulmonary arterial pressure and biventricular remodeling. CAVI may play an important role in cardiovascular interactions in patients with CTEPH.

Changes in blood pressure and arterial stiffness monitored using the cardio-ankle vascular index during hemodialysis

During hemodialysis (HD), blood pressure (BP) changes are frequently observed. However, the mechanism of BP changes during HD has not been fully clarified. The cardio-ankle vascular index (CAVI) reflects the arterial stiffness of the arterial tree from the origin of the aorta to the ankle independent from BP during measurement. Additionally, CAVI reflects functional stiffness in addition to structural stiffness. We aimed to clarify the role of CAVI in regulating the BP system during HD. We included 10 patients undergoing 4-hour HD (total 57 HD sessions). Changes in the CAVI and various hemodynamic parameters were evaluated during each session. During HD, BP decreased and CAVI significantly increased (CAVI, median [interquartile range]; 9.1 [8.4-9.8] [0 min] to 9.6 [9.2-10.2] [240 min], p < 0.05). Changes in CAVI from 0 min to 240 min were significantly correlated with water removal rate (WRR) (r = -0.42, p = 0.002). Changes in CAVI at each measurement point were negatively correlated with ΔBP (Δsystolic BP_{each MP}, r = -0.23, p < 0.0001; Δdiastolic BP_{each MP}, r = -0.12, p = 0.029). Whereas one patient exhibited a simultaneous decrease in BP and CAVI during the initial 60 min of HD. Arterial stiffness monitored with CAVI generally increased during HD. CAVI elevation is associated with decreased WWR and BP. An increase in CAVI during HD may reflect the contraction of smooth muscle cells and play an important role in BP maintenance. Hence, measuring CAVI during HD may distinguish the cause of BP changes.

Cold Pressor Test Influences the Cardio-Ankle Vascular Index in Healthy Overweight Young Adults

Objective

The cold pressor test (CPT) has been shown a potential sympathoexcitatory stimulus which increases aortic pulse wave velocity and the aortic augmentation index, suggesting that noninvasively, arterial stiffness parameters are altered by the CPT. The cardio-ankle vascular index (CAVI) is widely used for reflecting arterial stiffness, and the ankle-brachial index (ABI) for evaluating peripheral artery disease in obesity. We aimed to assess CAVI and ABI in overweight young adults in the context of sympathetic activation by using the CPT.

Methods

160 participants were divided into 2 groups: 86 normal-weight (body mass index [BMI] 18.50-22.99 kg/m²) and 74 overweight (BMI ≥23 kg/m²). The CPT was performed by immersing a participant's left hand into cold water (3-5°C) for 3 min, and CAVI and ABI assessment.

Results

At baseline, the CAVI in the overweight group was significantly less than that in the normal-weight group (5.79 ± 0.85 vs. 6.10 ± 0.85; p < 0.05). The mean arterial pressure (MAP) for overweight was significantly greater than that for normal-weight subjects (93.89 ± 7.31 vs. 91.10 ± 6.72; p < 0.05). During the CPT, the CAVI increased in both normal-weight and overweight subjects, the CAVI value was greater during the CPT in overweight subjects by 14.36% (6.62 ± 0.95 vs. 5.79 ± 0.85, p < 0.05) and in normal-weight subjects by 8.03% (6.59 ± 1.20 vs. 6.10 ± 0.85, p < 0.05) than those baseline values. The CPT evoked an increase in systolic blood pressure (SBP), diastolic BP (DBP), heart rate (HR,) and pulse pressure (PP) in both groups. After a 4-min CPT period, the CAVI returned values similar to the baseline values in both groups, and the SBP, DBP, MAP, and PP in overweight participants were significantly higher than those in normal-weight participants. However, there was no significant difference in the ABI at baseline, during CPT, and post-CPT in either group.

Conclusions

Our results indicated that the CAVI was influenced by sympathetic activation response to the CPT in both normal-weight and overweight young adults. Specifically, during the CPT, the percentage change of the CAVI in overweight response was greater in normal-weight participants than baseline values in each group. The ABI was not found significantly associated with CPT. These findings suggesting that sympathoexcitatory stimulus by CPT influence CAVI results.

Effect of nicorandil administration on cardiac burden and cardio-ankle vascular index after coronary intervention

Myocardial injury is a problem associated with percutaneous coronary intervention (PCI). This study aimed to clarify the role of nicorandil administration in preventing myocardial injury. This study included patients with stable angina who underwent PCI from November 2013 to June 2016. Of 58 consecutive patients, the first 20 patients received only saline infusion after PCI (control group); the other 38 patients received a continuous intravenous infusion of nicorandil and saline after PCI (nicorandil group). Troponin I and brain natriuretic peptide (BNP) levels were measured. Vascular parameters, such as blood pressure (BP), cardiac output, cardio-ankle vascular index (CAVI), and estimated systemic vascular resistance (eSVR), were measured. Troponin I of both groups increased 12 h after PCI. Changes in BNP levels between immediately after PCI and 12 h after PCI were significantly higher in the control than in the nicorandil group (10.8 ± 44.2 vs. − 2.6 ± 14.6 pg/ml, p = 0.04). In the nicorandil group, BP, eSVR, and CAVI decreased significantly at 12 h after PCI compared with those immediately after PCI (p < 0.0001), whereas no change was observed in the control group. In a single linear analysis, the change in BP (r = 0.36, p < 0.01) and nicorandil administration (r = − 0.47, p < 0.001) was significantly correlated with the change in CAVI, multiple regression analysis revealed that the changes in CO and eSVR were significant contributing factors for the changes in CAVI. PCI could result in myocardial injury and/or cardiac burden in patients with stable angina. Nicorandil administration after PCI may be effective in relieving the burden by decreasing arterial stiffness (CAVI).

Arterial Stiffness and Endothelial Function in Young Obese Patients - Vascular Resistance Matters

AIM

Motivated by the paradoxical and differing results of the early atherosclerosis related indices - Cardio-Ankle Vascular Index (CAVI) reflecting arterial stiffness and Reactive Hyperemia Index (RHI) evaluating endothelium dependent flow-induced vasodilation - in obesity, we aimed to assess CAVI and RHI in obese adolescents and young adults in the context of differences in systemic vascular resistance (SVR).

METHODS

We examined 29 obese (14f, 15.4 [12.3-18.5] y; BMI: 33.2±4.4 kg.m-2) and 29 non-obese gender and age matched adolescents and young adults (BMI: 21.02±2.3 kg.m-2). CAVI and RHI were measured using VaSera VS-1500 (Fukuda Denshi, Japan) and Endo-PAT 2000 (Itamar Medical, Israel), respectively. Hemodynamic measures were recorded using volume-clamp plethysmography (Finometer Pro, FMS, Netherlands) and impedance cardiography (CardioScreen 2000, Medis GmbH, Germany). SVR and sympathetic activity related indices - Velocity Index (VI) and Heather Index (HI), and LFSAP (spectral power in low frequency band of systolic blood pressure oscillations) were determined.

RESULTS

In obese group, CAVI (4.59±0.88 vs. 5.18±0.63, p=0.002) and its refined version CAVI0 (6.46±1.39 vs.7.33±0.99, p=0.002) were significantly lower. No significant difference in RHI was found. SVR and sympathetic activity indices were all significantly lower in the obese group than in the non-obese group. RHI correlated positively with SVR (r=0.390, p=0.044) in obese subjects.

CONCLUSION

Our results indicate that both indices used for the detection of early atherosclerotic changes are influenced by vascular tone. Vascular resistance could influence CAVI and RHI results impairing their interpretation.

Constitutive interpretation of arterial stiffness in clinical studies: a methodological review

Clinical assessment of arterial stiffness relies on noninvasive measurements of regional pulse wave velocity or local distensibility. However, arterial stiffness measures do not discriminate underlying changes in arterial wall constituent properties (e.g., in collagen, elastin, or smooth muscle), which is highly relevant for development and monitoring of treatment. In arterial stiffness in recent clinical-epidemiological studies, we systematically review clinical-epidemiological studies (2012–) that interpreted arterial stiffness changes in terms of changes in arterial wall constituent properties (63 studies included of 514 studies found). Most studies that did so were association studies (52 of 63 studies) providing limited causal evidence. Intervention studies (11 of 63 studies) addressed changes in arterial stiffness through the modulation of extracellular matrix integrity (5 of 11 studies) or smooth muscle tone (6 of 11 studies). A handful of studies (3 of 63 studies) used mathematical modeling to discriminate between extracellular matrix components. Overall, there exists a notable gap in the mechanistic interpretation of stiffness findings. In constitutive model-based interpretation, we first introduce constitutive-based modeling and use it to illustrate the relationship between constituent properties and stiffness measurements (“forward” approach). We then review all literature on modeling approaches for the constitutive interpretation of clinical arterial stiffness data (“inverse” approach), which are aimed at estimation of constitutive properties from arterial stiffness measurements to benefit treatment development and monitoring. Importantly, any modeling approach requires a tradeoff between model complexity and measurable data. Therefore, the feasibility of changing in vivo the biaxial mechanics and/or vascular smooth muscle tone should be explored. The effectiveness of modeling approaches should be confirmed using uncertainty quantification and sensitivity analysis. Taken together, constitutive modeling can significantly improve clinical interpretation of arterial stiffness findings.

Inverse Relationship between Sleep Duration and Cardio-Ankle Vascular Index in Children

AIM

Poor sleep has been shown to be associated with the development of cardiovascular risk factors, such as obesity, in both adults and children. This study aimed to investigate the relationship between sleep duration and arterial stiffness indices in Japanese children and early adolescents.

METHODS

The data on 102 students (56 males, 46 females; mean age, 11.9±1.8 years) were analyzed. As non-invasive arterial stiffness parameters, the cardio-ankle vascular index (CAVI) and heart-ankle pulse wave velocity (haPWV) were evaluated. Their students' sleep habits (bedtime and wake times on a usual weekday) were investigated using questionnaires, and based on these, their sleep durations were calculated.

RESULTS

The CAVI values in the males and females were 4.8±0.9 and 4.7±0.9 (arbitrary unit), respectively. haPWV values in the males and females were 5.5±0.6 and 5.4±0.6 m/s, respectively. Sleep duration in the males, but not in the females, was negatively correlated with CAVI (r=－0.356) and haPWV (r=－0.356), suggesting that students with short sleep duration could have increased arterial stiffness. After adjusting for confounders, such as age, sex, systolic blood pressure, heart rate, adiposity, and physical fitness, the correlation of sleep duration with CAVI, but not with haPWV, was still significant (partial r=－0.253, p＜0.05).

CONCLUSION

Our findings suggest that shorter sleep duration influences arterial stiffening even in childhood.

Relationship between cardiovascular risk factors and hemorheology assessed by microchannel method in patients with type 2 diabetes mellitus

Aim

In addition to atherosclerosis, impairment of blood rheology is an important factor in cardiovascular events. The present study attempted to clarify the relationship between hemorheology and cardiovascular risk factors in patients with type 2 diabetes mellitus assessed by a microchannel method.

Methods

We enrolled 294 patients with type 2 diabetes mellitus (109 males and 185 females; mean age, 69 ± 11 years) with no history of cardiovascular events. Hemorheology was evaluated with a microchannel array flow analyzer, and the relationship between whole-blood passage time (WBPT) and various clinical parameters was examined.

Results

WBPT was significantly correlated with advanced glycation end-product (AGE) levels at the skin (r = 0.49, p < 0.001), serum reactive oxygen metabolite concentrations (oxidative stress markers) (r = 0.25, p < 0.001), the cardio-ankle vascular index (CAVI, arterial function marker) (r = 0.32, p < 0.001), and a number of classical cardiovascular risk factors in an individual (r = 0.45, p < 0.001). Multiple regression analysis revealed that these factors were selected as independent variables for WBPT as a subordinate factor.

Conclusion

Hemorheology is significantly associated with novel cardiovascular risk factors, such as AGEs, in vivo oxidative stress, and CAVI, and clustering of classical cardiovascular risk factors in patients with type 2 diabetes mellitus.

Clinical assessment of arterial stiffness with cardio-ankle vascular index: theory and applications

Arterial stiffness is often assessed in clinical medicine, because it is not only an important factor in the pathophysiology of blood circulation but also a marker for the diagnosis and the prognosis of cardiovascular diseases. Many parameters have so far been proposed to quantitatively represent arterial stiffness and distensibility, such as pressure-strain elastic modulus (Ep), stiffness parameter (β), pulse wave velocity (PWV), and vascular compliance (Cv). Among these, PWV has been most frequently applied to clinical medicine. However, this is dependent on blood pressure at the time of measurement, and therefore it is not appropriate as a parameter for the clinical evaluation of arterial stiffness, especially for the studies on hypertension. On the contrary, stiffness parameter β is an index reflecting arterial stiffness without the influence of blood pressure. Recently, this parameter has been applied to develop a new arterial stiffness index called cardio-ankle vascular index (CAVI). Although this index is obtained from the PWV between the heart and the ankle, it is essentially similar to the stiffness parameter β, and therefore it does not depend on blood pressure changes during the measurements. CAVI is being extensively used in clinical medicine as a measure for the evaluation of cardiovascular diseases and risk factors related to arteriosclerosis. In the present article, we will explain the theoretical background of stiffness parameter β and the process to obtain CAVI. And then, the clinical utility of CAVI will be overviewed by reference to recent studies.

Cardio-ankle vascular index (CAVI) differentiates pharmacological properties of vasodilators nicardipine and nitroglycerin in anesthetized rabbits

Cardio-ankle vascular index (CAVI) has been developed for measurement of vascular stiffness from the aorta to tibial artery, which is clinically utilized for assessing the progress of arteriosclerosis. In this study, we established measuring system of the CAVI in rabbits, and assessed whether the index could reflect different pharmacological actions of nitroglycerin and nicardipine on the systemic vasculature. Rabbits were anesthetized with halothane, and the CAVI was calculated from the well-established basic equations with variables obtained from brachial and tibial blood pressure and phonocardiogram. Nicardipine (1, 3 and 10 μg/kg, i.v.) decreased the blood pressure, femoral vascular resistance, and heart-ankle pulse wave velocity (haPWV). Meanwhile, no significant change was detected in the CAVI at the low or middle dose, which reflects the defining feature of the CAVI that is independent of blood pressure. The index increased at the high dose. Nitroglycerin (2, 4 and 8 μg/kg, i.v.) decreased the blood pressure, femoral vascular resistance, and haPWV. Meanwhile, the CAVI was decreased during the nitroglycerin infusion, which may reflect its well-known pharmacological action dilating conduit arteries. These results suggest that the CAVI differentiates the properties of these vasodilators in vivo.

Evaluation of blood pressure control using a new arterial stiffness parameter, cardio-ankle vascular index (CAVI)

Arterial stiffness has been known to be a surrogate marker of arteriosclerosis, and also of vascular function. Pulse wave velocity (PWV) had been the most popular index and was known to be a predictor of cardiovascular events. But, it depends on blood pressure at measuring time. To overcome this problem, cardio-ankle vascular index (CAVI) is developed. CAVI is derived from stiffness parameter β by Hayashi, and the equation of Bramwell-Hill, and is independent from blood pressure at a measuring time. Then, CAVI might reflect the proper change of arterial wall by antihypertensive agents.

CAVI shows high value with aging and in many arteriosclerotic diseases and is also high in persons with main coronary risk factors. Furthermore, CAVI is decreased by an administration of α₁ blocker, doxazosin for 2-4 hours, Those results suggested that CAVI reflected the arterial stiffness composed of organic components and of smooth muscle cell contracture. Angiotensin II receptor blocker, olmesartan decreased CAVI much more than that of calcium channel antagonist, amlodipine, even though the rates of decreased blood pressure were almost same. CAVI might differentiate the blood pressure-lowering agents from the point of the effects on proper arterial stiffness.

This paper reviewed the principle and rationale of CAVI, and the possibilities of clinical applications, especially in the studies of hypertension.

Effects of dividing amlodipine daily doses on trough drug concentrations and blood pressure control over a 24-hour period

BACKGROUND

In the treatment of hypertension, once-daily administration of long-acting antihypertensive drugs has been recommended for the improvement of treatment adherence; however, it is unclear whether dividing daily doses has the additional benefit of more ideal blood pressure (BP) control over a 24-hour period.

OBJECTIVE

The aim of the study was to investigate whether dividing a 10-mg daily dose of amlodipine, a long-acting calcium channel blocker, is associated with increased trough plasma amlodipine concentrations, reduced arterial stiffness, and improved BP control over a 24-hour period.

METHODS

Outpatients with essential hypertension were included this open-label, 2-period crossover study. The patients were administered amlodipine 10 mg/d in 2 divided doses for 8 weeks. At week 4, blood was collected just before amlodipine administration for the evaluation of trough plasma amlodipine concentrations. At week 8, 24-hour, daytime, nighttime, and early morning BP, as well as arterial stiffness, were measured using ambulatory BP monitoring (ABPM) and cardio-ankle vascular index (CAVI), respectively. In the subsequent study period, amlodipine 10 mg/d was administered once daily, and the same tests were performed at the same timings as in period 1.

RESULTS

Ten patients were enrolled (7 men, 3 women; mean age, 61.0 [15.3] years). Mean 24-hour BP with twice-daily administration was not significantly lower than that with once-daily administration (129.7 [7.3]/80.1 [7.9] mm Hg vs 130.5 [11.8]/80.1 [7.9] mm Hg, respectively). Similarly, there were no significant differences in daytime, nighttime, or early morning BP between twice- and once-daily administration. In addition, the differences in trough plasma amlodipine concentrations (22.37 [7.66] ng/mL vs 20.57 [8.22] ng/mL) and CAVI values (8.2 [1.8] vs 8.5 [1.0]) were not significantly different between twice- and once-daily administration.

CONCLUSIONS

Administering amlodipine in 2 divided doses was not associated with increased trough plasma amlodipine concentrations, reduced arterial stiffness, or improved BP control over a 24-hour period in patients with essential hypertension.

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.