Establishment of the cardio-ankle vascular index in patients with obstructive sleep apnea.
ABSTRACT An arterial stiffness parameter, the cardio-ankle vascular index (CAVI), has been developed. CAVI is adjusted for BP and can be used to measure arterial stiffness with little influence of BP. The purpose of this study was to evaluate the reproducibility, validity, and clinical usefulness of CAVI among patients with obstructive sleep apnea (OSA), who often have elevated BP during measurement.
Overall, 543 consecutive patients with OSA were studied. CAVI was automatically calculated from the pulse volume record, BP, and the vascular length from the heart to the ankle. First, CAVI was measured three times on different days in 25 patients to evaluate its reproducibility. Second, the correlation between CAVI and BP was assessed. Third, patients were classified into two groups (mild OSA or moderate-to-severe OSA), and the CAVIs of these groups were compared. Fourth, the correlation between CAVI and carotid intima-media thickness (IMT) was also assessed in 74 patients.
The mean coefficient of variation was 2.8. CAVI demonstrated weak or no correlations with BP (with systolic BP, r = 0.184; with diastolic BP, r = 0.223). Patients with moderate-to-severe OSA (n = 469) had a significantly greater CAVI than patients with mild OSA (p = 0.034). CAVI was positively correlated with IMT (r = 0.487).
The measurement of CAVI demonstrated good reproducibility and was not affected by the BP during measurement. Additionally, CAVI was positively correlated with another arteriosclerosis indicator. CAVI was higher in patients with more severe OSA and is regarded as a clinically useful index for the progression of vascular damage.
- SourceAvailable from: Daiji Nagayama[Show abstract] [Hide abstract]
ABSTRACT: 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.Current Hypertension Reviews 02/2013; 9(1):66-75.
- [Show abstract] [Hide abstract]
ABSTRACT: Although arteriosclerotic diseases have been reported to be frequently complicated by diabetes mellitus (DM), a detailed relationship between hyperglycemia and arterial stiffness has not been fully clarified. We investigated the influence of hyperglycemia on arterial stiffness using the cardio-ankle vascular index (CAVI), which is a new method for estimating arterial stiffness.Journal of diabetes investigation. 01/2013; 4(1):82-7.
- [Show abstract] [Hide abstract]
ABSTRACT: We evaluated early atherosclerotic lesions in 20 non-smokers with newly diagnosed Obstructive Sleep Apnoea (OSA) and without known comorbidities by measuring common carotid artery intima media thickness (CCA-IMT), transcranial Doppler ultrasound (TCD), and ankle brachial index (ABI). These were compared with 20 healthy age- and BMI-matched controls. In OSA patients, CCA-IMT was not significantly higher vs. controls (0.74±0.17 vs. 0.66±0.12 mm, p=0.201) and it was positively correlated with neck circumference (r=0.466, p=0.039), arousal index (r=0.663, p=0.001), gamma-glutamyl transpeptidase activity (r=0.474, p=0.035) while it was negatively correlated with Forced Expiratory Volume in 1 sec (r=-0.055, p=0.012). No difference was noted between patients and controls in terms of vascular stenosis on TCD examination, while asymptomatic peripheral artery disease was found in one patient with OSA. In conclusion, OSA patients without known comorbidities exhibit a non-significant increase in CCA-IMT without further evidence of vascular disease, but additional experience in a larger patient series is needed.The Open Cardiovascular Medicine Journal 01/2013; 7:61-8.