P129 Arterial Stiffness in Bicuspid or Tricuspid Aortic Valve Aortopathy Using Magnetic Resonance Imaging: Crossing the Physical and Hemodynamic limits? (original) (raw)
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There has been a growing awareness over the past decade that stiffening of the aorta, and its attendant effects on hemodynamics, is both an indicator and initiator of diverse cardiovascular, neurovascular, and renovascular diseases. Although different clinical metrics of arterial stiffness have been proposed and found useful in particular situations, there remains a need to understand better the complex interactions between evolving aortic stiffness and the hemodynamics. Computational fluid-solid-interaction (FSI) models are amongst the most promising means to understand such interactions for one can parametrically examine effects of regional variations in material properties and arterial geometry on local and systemic blood pressure and flow. Such models will not only increase our understanding, they will also serve as important steps towards the development of fluid-solid-growth (FSG) models that can further examine interactions between the evolving wall mechanics and hemodynamics that lead to arterial adaptations or disease progression over long periods. In this paper, we present a consistent quantification and comparison of regional nonlinear biaxial mechanical properties of the human aorta based on 19 data sets available in the literature and we calculate associated values of linearized stiffness over the cardiac cycle that are useful for initial large-scale FSI and FSG simulations. It is shown, however, that there is considerable variability amongst the available data and consequently that there is a pressing need for more standardized biaxial testing of the human aorta to collect data as a function of both location and age, particularly for young healthy individuals who serve as essential controls.
Aortic stiffness: pathophysiology, clinical implications, and approach to treatment
Integrated Blood Pressure Control, 2014
Aortic stiffness is a hallmark of aging, and classic cardiovascular risk factors play a role in accelerating this process. Current changes in medicine, which focus on preventive care, have led to a growing interest in noninvasive evaluation of aortic stiffness. Aortic stiffness has emerged as a good tool for further risk stratification because it has been linked to increased risk of atherosclerotic heart disease, myocardial infarction, heart failure, and stroke. This has led to the invention and validation of multiple methods to measure aortic stiffness. Pulse wave velocity is emerging as the gold standard for evaluation of aortic stiffness. This review focuses on the pathophysiology involved in aortic stiffness, methods available for evaluation of aortic stiffness, the importance of central pressure as a predictor of future cardiovascular events, and therapies that affect aortic stiffness.
HVM Bioflux, 2014
Introduction Over recent years, research on cardiovascular disease risk factors has emphasized the impact of central aortic pressure as a cardiovascular risk factor of greater importance than systolic pressure and brachial artery pulse pressure, central aortic pressure being the actual pressure felt by the heart directly. This kind of pressure is different from the frequently measured brachial pressure, being modified by its circulating speed or the reflected pulse wave transmitted through the arterial walls (dependent on vascular wall stiffness) and by the magnitude of the reflected wave (Stephanie et al 2008). Therefore, elevated pulse wave velocity (PWV) causes the reflected wave to return to the level of the aortic valve during systole, compared to the beginning of diastole, as it would be normal, thus creating an increase in ventricular pressure and an additional mechanical stress on the aortic valve. Material and method Patients were selected from those admitted to the interna...
Arterial stiffness in aortic stenosis - complex clinical and prognostic implications
Biomedical Papers of the Faculty of Medicine of Palacký University, Olomouc Czech Republic, 2022
Arterial stiffness and degenerative aortic stenosis (AoS) are frequently associated leading to a combined valvular and vascular load imposed on the left ventricle (LV). Vascular load consists of a pulsatile load represented by arterial stiffness and a steady load corresponding to vascular resistance. Increased vascular load in AoS has been associated with LV dysfunction and poor prognosis in pre-intervention state, as well as after aortic valve replacement (AVR), suggesting that the evaluation of arterial load in AoS may have clinical benefits. Nevertheless, studies that investigated arterial stiffness in AoS either before or after AVR used various methods of measurement and their results are conflicting. The aim of the present review was to summarize the main pathophysiological mechanisms which may explain the complex valvulo-arterial interplay in AoS and their consequences on LV structure and function on the patients' outcome. Future larger studies are needed to clarify the complex hemodynamic modifications produced by increased vascular load in AoS and its changes after AVR. Prospective evaluation is needed to confirm the prognostic value of arterial stiffness in patients with AoS. Simple, non-invasive, reliable methods which must be validated in AoS still remain to be established before implementing arterial stiffness measurement in patients with AoS in clinical practice.
European heart journal cardiovascular Imaging, 2013
We compared flow and wall shear stress (WSS) patterns in the ascending aorta of individuals with either bicuspid aortic valve (BAV) or tricuspid aortic valve (TAV) using four-dimensional cardiovascular magnetic resonance (4D-CMR). BAV are known to be associated with dilation and dissection of the ascending aorta. However, the cause of vessel disease in patients with BAVs is unknown. Inborn connective tissue disease and also dilation secondary to increased WSS because of altered blood flow patterns in the ascending aorta are discussed as causes for dilation of the aorta. WSS can be estimated non-invasively by 4D-CMR. Eighteen, otherwise, healthy individuals with functionally normal BAVs were compared prospectively with an age- and sex-matched control group of healthy individuals with TAV. Blood flow data were obtained by 4D-CMR visualization and WSS was calculated with specific software tools. Eighty-five per cent of the individuals with BAVs showed a high-grade helical flow pattern ...
Journal of the American College of Cardiology, 2011
The aorta stiffens with aging, a process that is accelerated by arterial hypertension. Decreased arterial compliance is one of the earliest detectable manifestations of adverse structural and functional changes within the vessel wall. The use of different imaging techniques optimized for assessment of vascular elasticity and quantification of luminal and vessel wall parameters allows for a comprehensive and detailed view of the vascular system. In addition, several studies have also documented the prognostic importance of arterial stiffness (AS) in various populations as an independent predictor of cardiovascular morbidity and all-cause mortality. Measurement of AS by applanation tonometry with pulse-wave velocity has been the gold-standard method and is wellvalidated in large populations as a strong predictor of adverse cardiovascular outcomes. Because aortic stiffness depends on the prevailing blood pressure, effective antihypertensive treatment is expected to reduce it in proportion to the blood pressure reduction. Nevertheless, drugs lowering blood pressure might differ in their effects on structure and function of the arterial walls. This review paper not only will discuss the current understanding and clinical significance of AS but also will review the effects of various pharmacological and nonpharmacological interventions that can be used to preserve the favorable profile of a more compliant and less stiff aorta. (J Am Coll Cardiol 2011;57:1511-22)
The American Journal of Cardiology, 2011
Bicuspid aortic valve (BAV) is frequently associated with aortic wall abnormalities, including dilation of the ascending aorta and even dissection. We propose 2 new indexes of aortic wall biophysical properties, the maximum rates of systolic distension and diastolic recoil (MRSD and MRDR, respectively), in patients with BAV and matched control subjects. We evaluated 53 consecutive young patients with BAV (36 males, mean age 16 ؎ 4 years) with mild aortic valve disease and a control group of 22 age-and gender-matched healthy volunteers. All subjects underwent a cardiac magnetic resonance imaging study that included phase velocity mapping and cine acquisition at several aortic levels. The MRSD and MRDR were measured in the ascending aorta in both patients with BAV and controls. Of the 53 patients with BAV, 26 had enlarged ascending aortas (dilated BAV), and 27 had a normal aortic diameter (nondilated BAV). Compared to controls, the MRSD was significantly lower in the whole BAV group (4. , in patients with dilated BAV (4.5 ؎ 1.1 p <0.0001), and in those with nondilated BAV (4.3 ؎ 1.0, p <0.0001). The MRDR was greater in the whole BAV group (؊4 ؎ 1.2 vs ؊7.6 ؎ 2.7, p <0.0001), in the dilated BAV group (؊3.9 ؎ 1.3, p <0.0001), and in the nondilated BAV group (؊4.1 ؎ 1.2, p <0.0001). A receiver operating characteristic curve analysis of MRSD distinguished BAV from controls with 100% sensitivity and 95% specificity. In conclusion, MRSD and MRDR were slower in the patients with BAV than in the controls, regardless of the dimensions of the ascending aorta.