Quantitative Assessment of Aortic Elasticity With Aging Using Velocity-Vector Imaging and Its Histologic Correlation

Abstract

A ging is a physiological process associated with an increase in cardiovascular morbidity and mortality even in the absence of known cardiovascular risk factors. 1 The main feature of arterial aging is the thickening, dilation, and stiffening of the artery, 2,3 which is described as senile arteriosclerosis. 4 The repeated cycles of distension and elastic recoil of the arterial wall accelerate the fragmentation and depletion of elastin, leading to a substantial increase in the inner diameter and the deposition of collagen with increasing stiffness.5 As a result, the stiffening of the proximal aorta and early wave reflection give rise to the development of isolated systolic hypertension, left ventricular hypertrophy, and heart failure with a basis on a ventricular-vascular coupling mechanism; all of these factors lead to an increase of cardiovascular mortality with aging. 5,6 Thus, the assessment of mechanical properties of the artery in humans using noninvasive techniques is of growing importance. For quantification of aortic elastic properties, there are many noninvasive measures, including pulse wave velocity and echocardiographic techniques presented as distensibility, strain, and pressure-strain elastic moduli.7-11 However, these methods represent a global estimation of arterial elasticity and, therefore, have limitations because arterial changes usually begin as regional changes. With the availability of more advanced ultrasound techniques, a novel automated speckletracking method using velocity-vector imaging (VVI) software has facilitated the assessment for angle-independent and instantaneous quantification of arterial elastic properties by providing the 2-dimensional-derived tissue radial velocity (RV), circumferential strain, and strain rate in both regional and segmental aspects. 12-15We previously showed that arterial assessment using VVI represents a new method for quantifying vascular alteration not only in the clinical conditions of vasculitis 12,13 but also in other disorders associated with aging.16 Despite these investigations, further histological validation will facilitate the clinical application of VVI. Therefore, the purpose of this study was to compare the parameters of VVI between young and senescent dogs and to assess the correlations between the VVI parameters and histological changes. Objective-Velocity-vector imaging (VVI) represents a valuable new method for noninvasive quantification of vascular properties associated with aging. The purpose of this study was to assess the correlations between VVI parameters and histological changes with aging. Approach and Results-Fourteen mongrel dogs were classified as either young (n=7; age, 1-2 years; female; weighing 22-29 kg) or senescent (n=7; age, 8-12 years; female; weighing 36-45 kg). The short-axis image of the descending thoracic aorta was obtained for VVI analysis with transesophageal echocardiography. The location of the image was identified using fluoroscopic guidance, and the aortic tissue was extracted. After dividing the aortic wa...

Systems Biology and Noninvasive Imaging of Atherosclerosis

“…For example, transesophageal US was recently employed in mongrel dogs to quantify changes in aortic area and elastic properties from velocity-vector imaging (VVI) with aging 80 . Another study used a combination of multi-vessel IVUS and novel near infra-red spectroscopy (NIRS) 81, 82 to evaluate features of vulnerability in fibroatheromas of diabetic/hypercholesterolemic pigs 83 .…”

Aortic Valve Disease and Vascular Mechanics: Two‐Dimensional Speckle Tracking Echocardiographic Analysis

“…Vascular mechanics similarly have been validated in vivo and in vitro , using sonomicrometry. Moreover, an association of the collagen content of the vessels and vascular mechanics has also been proved, promoting aortic mechanics as a new imaging surrogate of vascular stiffening …”

“…Moreover, an association of the collagen content of the vessels and vascular mechanics has also been proved, promoting aortic mechanics as a new imaging surrogate of vascular stiffening. 13 Degenerative AVD is currently viewed as a systemic disease evoking changes in arterial wall 1 These authors contributed equally to this work. rigidity and compliance, a concept borne out mainly in aortic stenosis (AS).…”

Ultrasonographic evaluation of segmental function of the aorta and carotid arteries in healthy infants

“…Двумерная (2D) ультразвуковая визуализация циркумференциальной сосудистой деформации (изменение длины ткани при максимальной деформации по окружности в систолу относительно начальной длины) с использованием визуализации вектора скорости движения (vector velocity imaging, VVI) -это относительно новая методика, которая применяется в исследованиях артерий и непосредственно характеризует механику сосуда, его упруго-эластические свойства [2][3][4]. Очевидные преимущества оценки циркумференциальной деформации состоят в том, что показатель отражает локальную (в выбранной зоне интереса) окружностную эластичность (процент максимального «удлинения» волокон артериальной стенки и скорости этого удлинения при максимальном растяжении), тогда как традиционно оцениваемый показатель артериальной жесткости (β1) является косвенным расчетным параметром, учитывающим изменение внутреннего диаметра просвета артерии в радиальном (не окружностном) направлении [2,4]. Y. Oishi и соавт.…”

“…предложили на основе циркумференциальной деформации проводить расчет артериальной жесткости (β2) [3]. В литературе представлена широкая валидация этого показателя и изучение его диагностической и прогностической ценности у взрослых [2,[4][5][6]. Однако у детей исследования деформации и артериальной жесткости единичны, а у детей первого года жизни не проводились.…”