This work is under the financial support from National key research and development program of China (Grant No. 2017YFC0111800) and the Shanghai municipal government (Grant ID. 2013ZYJB0902 and 15GWZK1002). Dr. Yi Zhang was supported by the National Nature Science Foundation of China (Grant ID. 81300239 and 81670377).

This protocol was approved by the Ethics Committee of Shanghai Tenth People&#39;s Hospital.
1. Recruitment of Participants
<ol>
	<li>Include Adults with a moderate heart rate (40 &#60; HR &#60; 160).</li>
	<li>Use the following exclusion criteria.
	<ol>
		<li>Exclude those without internal arteriovenous fistula for renal dialysis or any other peripheral arteriovenous fistula like that.</li>
		<li>Exclude those without peripheral arterial spasm, for example the Raynaud disease.</li>
		<li>Exclude those without aortic valvular stenosis (transprosthetic pressure gradient &#62; 60 mmHg).</li>
		<li>Exclude those without second or third-degree atrioventricular (AV) block.</li>
		<li>Exclude those without atrial fibrillation or atrial flutter.</li>
		<li>Exclude those without unstable carotid atherosclerotic plaques that may rupture after kneading. 9) Without cognitive impairment or unable to cooperate.</li>
	</ol>
	</li>
	<li>Ensure that the participants&#39; bladder is empty.</li>
	<li>Have participants refrain from smoking, tobacco use or caffeine use for at least 3 hours before the measurement. Abstain from alcohol for at least 12 hours before the measurement. Fast for at least 3 hours before the measurement.</li>
</ol>
2. Measurements of Vascular TOD
NOTE: cf-PWV and PWA measurements, like conventional four-limb blood pressure measurements, are performed through a non-invasive evaluating method. A standard protocol is crucial to obtain an accurate value, especially when there are multiple operators. Make sure to practice the method before the actual operation. The participant&#39;s cooperation is key for the measurement of cf-PWV.
<ol>
	<li>Explain the procedure to the participant and obtain permission.</li>
	<li>Measure the body height and weight before the start of the measurements.</li>
	<li>Explain that the process may take 5-10 min and involves letting the participant lie on the bed.
	<ol>
		<li>Keep the patient&#39;s skin clean and dry when shifting supine positions. If the patient&#39;s skin is damp because of sweating, then wipe dry the skin.</li>
		<li>Perform the measurements in a quiet room with a stable room temperature.</li>
	</ol>
	</li>
	<li>Put the participant&#39;s hands next to their body to make sure there is a smooth, undisturbed ECG signal. Connect up to 3-lead ECG monitors, positioning three electrodes (RA, LL, LA) according to the following diagram (Figure 2). 
	NOTE: The use of disposable electrodes is recommended. The ECG leads and wires cannot be used in other ECG drawing equipment.</li>
	<li>Have the patient rest for at least 5 minutes in the supine position. Then measure the patient&#39;s blood pressure with a semiautomatic oscillometric device. 
	NOTE: The blood pressure is measured according to the recommendations of the European Society of Hypertension17.</li>
	<li>Have the patient rest for at least 2 minutes. 
	NOTE: The peripheral vascular dilatation caused by artery occlusion when measuring brachial artery blood pressure will change the brachial artery pulse transmission. Resting is essential to avoid excessive deviation.</li>
	<li>While the participant rests, enter the participant&#39;s detailed information, including the supine blood pressure, body height, body weight and operator&#39;s name, into the measurement device (Figure 3).</li>
	<li>After entering all the information, keep the participants in a supine position.</li>
	<li>Manually measure the following parameters (mm) (Figure 3).
	<ol>
		<li>Measure the distance from the suprasternal notch (SSN) to the remote detection point (femoral artery).</li>
		<li>Measure the distance from the sternal notch to the proximal (carotid artery) detection point.</li>
		<li>Measure the distance from the remote detection point (femoral artery) to the proximal (carotid artery) detection point (cf-distance).</li>
	</ol>
	</li>
	<li>Choose the PWA mode. Enter &#39;0&#39; as SSN-carotid distance, and enter 0.8*cf-distance as SSN-femoral distance. If the device doesn&#39;t accept &#39;0&#39;, put another value as the SSN-carotid distance and add that value to the 80% cf distance as SSN-femoral distance5. 
	NOTE: The operator should sit in a most comfortable position.</li>
	<li>Press the button to capture data. Put the tonometer on the radial artery fluctuation point (1-2 cm above the radial styloid process at a point where the fluctuation is strong and stable) to measure the central blood pressure.
	<ol>
		<li>Maintain the position of the tonometer to obtain a steady waveform on the computer. Once the quality and reproducibility of the tonometry measurements reach the standard, the signal recording is finished automatically by the computer.</li>
		<li>Keep the tonometer at 90&#176;.</li>
		<li>To avoid parasite movement, immobilize the tonometer near the base with the fingers, firmly affix the tonometer to the skin. 
		NOTE: The software automatically records the data as soon as the tonometer is placed in contact with the measurement site. The quality and reproducibility of the tonometry measurements are automatically tested. An operator index greater than 80% is considered as a reliable measurement. Pulse pressure amplification (PPA) is defined as the peripheral-to-central pulse pressure ratio and is calculated with the formula, PPA= (brachial SBP- brachial DBP)/ (central SBP- central DBP)-1. PWA can be observed on the device18 (Figure 4).</li>
	</ol>
	</li>
	<li>Choose the PWV mode. Put the tonometer on the carotid artery fluctuation point. Maintain the position of the tonometer to obtain a steady waveform on the computer. After recording a stable waveform for 15-20 seconds. Once the quality and reproducibility of the tonometry measurements reach the standard, finish recording manually (Figure 5).</li>
	<li>Put the tonometer on the femoral artery fluctuation point (1-2 cm below the midpoint of the inguinal ligament at a point where the fluctuation is stable). Maintain the position of the tonometer to record a steady waveform. After recording a stable waveform for 15-20 seconds, finish recording manually once the quality and reproducibility of the tonometry measurements reach the standard. The PWV value can be observed on the device cf-PWV &#8805; 10 m/s is considered as arterial stiffening (Figure 5)1.</li>
</ol>

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J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevalence,+Correlates,+and+Prognosis+of+Healthy+Vascular+Aging+in+a+Western+Community-Dwelling+Cohort:+The+Framingham+Heart+Study.">Prevalence, Correlates, and Prognosis of Healthy Vascular Aging in a Western Community-Dwelling Cohort: The Framingham Heart Study.</a> Hypertension. 70 (2), 267-274 (2017).</li><li>Reference Values for Arterial Stiffness, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determinants+of+pulse+wave+velocity+in+healthy+people+and+in+the+presence+of+cardiovascular+risk+factors:+'establishing+normal+and+reference+values.">Determinants of pulse wave velocity in healthy people and in the presence of cardiovascular risk factors: 'establishing normal and reference values.</a> Eur Heart J. 31 (19), 2338-2350 (2010).</li><li>Van Bortel, L. 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B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=General+cardiovascular+risk+profile+for+use+in+primary+care:+the+Framingham+Heart+Study.">General cardiovascular risk profile for use in primary care: the Framingham Heart Study.</a> Circulation. 117 (6), 743-753 (2008).</li><li>Conroy, R. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+ten-year+risk+of+fatal+cardiovascular+disease+in+Europe:+the+SCORE+project.">Estimation of ten-year risk of fatal cardiovascular disease in Europe: the SCORE project.</a> Eur Heart J. 24 (11), 987-1003 (2003).</li><li>Zethelius, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+multiple+biomarkers+to+improve+the+prediction+of+death+from+cardiovascular+causes.">Use of multiple biomarkers to improve the prediction of death from cardiovascular causes.</a> N Engl J Med. 358 (20), 2107-2116 (2008).</li><li>Vernooij, J. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypertensive+target+organ+damage+and+the+risk+for+vascular+events+and+all-cause+mortality+in+patients+with+vascular+disease.">Hypertensive target organ damage and the risk for vascular events and all-cause mortality in patients with vascular disease.</a> J Hypertens. 31 (3), 492-499 (2013).</li><li>van der Veen, P. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypertensive+Target+Organ+Damage+and+Longitudinal+Changes+in+Brain+Structure+and+Function:+The+Second+Manifestations+of+Arterial+Disease-Magnetic+Resonance+Study.">Hypertensive Target Organ Damage and Longitudinal Changes in Brain Structure and Function: The Second Manifestations of Arterial Disease-Magnetic Resonance Study.</a> Hypertension. 66 (6), 1152-1158 (2015).</li><li>Ji, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shanghai+Study:+cardiovascular+risk+and+its+associated+factors+in+the+Chinese+elderly-a+study+protocol+of+a+prospective+study+design.">Shanghai Study: cardiovascular risk and its associated factors in the Chinese elderly-a study protocol of a prospective study design.</a> BMJ Open. 7 (3), (2017).</li><li>O'Brien, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Practice+guidelines+of+the+European+Society+of+Hypertension+for+clinic,+ambulatory+and+self+blood+pressure+measurement.">Practice guidelines of the European Society of Hypertension for clinic, ambulatory and self blood pressure measurement.</a> J Hypertens. 23 (4), 697-701 (2005).</li><li>Agnoletti, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulse+wave+analysis+with+two+tonometric+devices:+a+comparison+study.">Pulse wave analysis with two tonometric devices: a comparison study.</a> Physiol Meas. 35 (9), 1837-1848 (2014).</li><li>Ji, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shanghai+Study:+cardiovascular+risk+and+its+associated+factors+in+the+Chinese+elderly-a+study+protocol+of+a+prospective+study+design.">Shanghai Study: cardiovascular risk and its associated factors in the Chinese elderly-a study protocol of a prospective study design.</a> BMJ Open. 7 (3), e013880 (2017).</li><li>Zhang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+study+of+central+blood+pressure+and+wave+reflection+obtained+from+tonometry-based+devices.">Comparison study of central blood pressure and wave reflection obtained from tonometry-based devices.</a> Am J Hypertens. 26 (1), 34-41 (2013).</li><li>Sharman, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+of+non-invasive+central+blood+pressure+devices:+ARTERY+Society+task+force+consensus+statement+on+protocol+standardization.">Validation of non-invasive central blood pressure devices: ARTERY Society task force consensus statement on protocol standardization.</a> Eur Heart J. 38 (37), 2805-2812 (2017).</li><li>Millasseau, S., Agnoletti, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-invasive+estimation+of+aortic+blood+pressures:+a+close+look+at+current+devices+and+methods.">Non-invasive estimation of aortic blood pressures: a close look at current devices and methods.</a> Curr Pharm Des. 21 (6), 709-718 (2015).</li><li>Olsen, M. 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The authors have nothing to disclose.

Here, we demonstrate a widely accessible methodology to assess the participants&#39; novel preclinical vascular TOD, arterial stiffness, evaluated by cf-PWV. In order to compare PWs with minimal hemodynamic differences between measurements done prior to devices, only accept data when the brachial systolic and diastolic BP varied by less than 3 mmHg. This reduces the deviation caused by human manipulation. In this protocol, the critical steps are to have standardized patient conditions using 80% of the direct straight dis...

Arterial stiffening is a good marker for vascular aging evaluation1,2. The measurement of arterial stiffening is traditionally conducted using a pulse wave velocity (PWV) methodology that is an important and reliable measure of arterial stiffness1,3,4,5. Specifically, PWV represents the stiffness of a specific arterial segment. The pulse wave is transmitted through the arterial vessels in a specific segment, and its speed is inversely related to the viscoelastic properties of the wall itself6. PWV value increases with arterial stiffening.
Carotid-femoral PWV (cf-PWV) and brachial-ankle PWV (ba-PWV) are the 2 most frequently applied PWV measurements. They are widely used in clinical practice, where cf-PWV is popular in western countries and ba-PWV is popular in Asian countries.7,8. In fact, cf-PWV has been considered as the &#39;gold-standard&#39; measurement of arterial stiffness1. For cf-PWV, it is taken as representative of the PWV for the entire aorta. Besides, for ba- PWV, there is no true arterial pathway linking the measurement sites (brachial to ankle). The estimated ba-PWV represents the PWV for the entirety of the central and peripheral arterial system9. A previous study has reported that cf-PWV is superior to ba-PWV in associations with asymptomatic hypertensive target organ damage (TOD)10 (Figure 1).
Non-invasive devices for regional stiffness equipped with a specific tonometer are increasingly being used to measure the stiffness of the carotid to femoral segment1. In cf-PWV measurements, this device and a handheld tonometer create a steady waveform on the computer that can record high resolution digital waveform images and the specific PWV values (Figure 2). All these measurements need to be standardized. Here, we show how to record a good quality cf-PWV with this non-invasive tonometry-based device in a real-world setting.
Some established cardiovascular risk prediction models such as the Framingham risk score and the SCORE Risk Charts are mainly calculated and sorted by conventional risk factors11,12. However, some novel biomarkers should be added into the risk assessment model to improve the risk stratification13. In literature, arterial stiffening is considered as an intermediate state between conventional risk factors and clinical cardiovascular events14. Thus, adding cf-PWV into the risk assessment model may be a tool for risk stratification15,16.
Here, we generate a methodology plan to assess participants&#39; cf-PWV, together with PWA, to establish a standard protocol for arterial stiffening assessment.

<table><tbody><tr><td>SphygmoCor tonometry-based device</td><td>AtCor Medical, Australia</td><td></td><td>For central blood pressures and cf-PWV</td></tr><tr><td>Electrodes</td><td>AtCor Medical, Australia</td><td></td><td>To record the ECG</td></tr><tr><td>Semiautomatic Oscillometric device</td><td>OMRON Healthcare, kyoto, Japan</td><td></td><td>To measure brachial BP</td></tr></tbody></table>

measuring the carotid to femoral pulse wave velocity (cf-pwv) to evaluate arterial stiffness

For the elderly, arterial stiffening is a good marker for aging evaluation and it is recommended that the arterial stiffness be determined noninvasively by the measurement of carotid to femoral pulse wave velocity (cf-PWV) (Class I; Level of Evidence A). In literature, numerous community-based or disease-specific studies have reported that higher cf-PWV is associated with increased cardiovascular risk. Here, we discuss strategies to evaluate arterial stiffness with cf-PWV. Following the well-defined steps detailed here, e.g., proper position operator, distance measurement, and tonometer position, we will obtain a standard cf-PWV value to evaluate arterial stiffness. In this paper, a detailed stepwise method to record a good quality PWV and pulse wave analysis (PWA) using a non-invasive tonometry-based device will be discussed.

Cf-PWV (with this method) and ba-PWV (with other method10) were conducted in all of the 2098 participants from Northern Shanghai Study19. Both cf-PWV and ba-PWV were used in the same logistic regression model. In this model, age and gender were adjusted. The results showed that only cf-PWV, but not ba-PWV, was significantly associated with increased IMT and arterial plaque, which indicates the superiority of cf-PWV over ba-PWV in the associa...

Watch this Scientific Journal Video about Measuring the Carotid to Femoral Pulse Wave Velocity Cf-PWV to Evaluate Arterial Stiffness at JoVE.com

Measuring the Carotid to Femoral Pulse Wave Velocity Cf-PWV to Evaluate Arterial Stiffness

This protocol describes a method to standardize the measurements of carotid-femoral pulse wave velocity to evaluate arterial stiffness.

Measuring the Carotid to Femoral Pulse Wave Velocity (Cf-PWV) to Evaluate Arterial Stiffness

For the elderly, arterial stiffening is a good marker for aging evaluation and it is recommended that the arterial stiffness be determined noninvasively ...

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17.3K Views.  Tongji University School of Medicine. This protocol describes a method to standardize the measurements of carotid-femoral pulse wave velocity to evaluate arterial stiffness.

Video: Measuring the Carotid to Femoral Pulse Wave Velocity Cf-PWV to Evaluate Arterial Stiffness

The Measurement and Treatment of Suppression in Amblyopia

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current estimates put the prevalence of amblyopia at approximately 1-3%1-3, the majority of cases being monocular2. Amblyopia is most frequently caused by ocular misalignment (strabismus), blur induced by unequal refractive error (anisometropia), and in some cases by form deprivation.
Although amblyopia is initially caused by abnormal visual input in infancy, once established, the visual deficit often remains when normal visual input has been restored using surgery and/or refractive correction. This is because amblyopia is the result of abnormal visual cortex development rather than a problem with the amblyopic eye itself4,5 . Amblyopia is characterized by both monocular and binocular deficits6,7 which include impaired visual acuity and poor or absent stereopsis respectively. The visual dysfunction in amblyopia is often associated with a strong suppression of the inputs from the amblyopic eye under binocular viewing conditions8. Recent work has indicated that suppression may play a central role in both the monocular and binocular deficits associated with amblyopia9,10 .
Current clinical tests for suppression tend to verify the presence or absence of suppression rather than giving a quantitative measurement of the degree of suppression. Here we describe a technique for measuring amblyopic suppression with a compact, portable device11,12 . The device consists of a laptop computer connected to a pair of virtual reality goggles. The novelty of the technique lies in the way we present visual stimuli to measure suppression. Stimuli are shown to the amblyopic eye at high contrast while the contrast of the stimuli shown to the non-amblyopic eye are varied. Patients perform a simple signal/noise task that allows for a precise measurement of the strength of excitatory binocular interactions. The contrast offset at which neither eye has a performance advantage is a measure of the "balance point" and is a direct measure of suppression. This technique has been validated psychophysically both in control13,14 and patient6,9,11 populations.
In addition to measuring suppression this technique also forms the basis of a novel form of treatment to decrease suppression over time and improve binocular and often monocular function in adult patients with amblyopia12,15,16 . This new treatment approach can be deployed either on the goggle system described above or on a specially modified iPod touch device15.

Amblyopia is a developmental disorder of the visual cortex that is often accompanied by strong suppression of one eye. We present a new technique for measuring and treating interocular suppression in patients with amblyopia that can be deployed using virtual reality goggles or a portable iPod Touch device.

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current ...

Pulse Wave Velocity Testing in the Baltimore Longitudinal Study of Aging

Carotid-femoral pulse wave velocity is considered the gold standard for measurements of central arterial stiffness obtained through noninvasive methods1.&#160;Subjects are placed in the supine position and allowed to rest quietly for at least 10 min prior to the start of the exam. The proper cuff size is selected and a blood pressure is obtained using an oscillometric device. Once a resting blood pressure has been obtained, pressure waveforms are acquired from the right femoral and right common carotid arteries. The system then automatically calculates the pulse transit time between these two sites (using the carotid artery as a surrogate for the descending aorta). Body surface measurements are used to determine the distance traveled by the pulse wave between the two sampling sites. This distance is then divided by the pulse transit time resulting in the pulse wave velocity. The measurements are performed in triplicate and the average is used for analysis.

Pulse wave velocity (PWV) measurement assesses arterial stiffness by a tonometry-based system that measures the speed with which arterial pressure wave travels along the arterial tree, typically approximating the time that it takes this wave to travel from the descending aorta (using the carotid artery as a surrogate) to the femoral artery. Carotid-femoral PWV increases two- to threefold across the adult lifespan.

Carotid-femoral pulse wave velocity is considered the gold standard for measurements of central arterial stiffness obtained through noninvasive ...

Assessment of Vascular Function in Patients With Chronic Kidney Disease

Patients with chronic kidney disease (CKD) have significantly increased risk of cardiovascular disease (CVD) compared to the general population, and this is only partially explained by traditional CVD risk factors. Vascular dysfunction is an important non-traditional risk factor, characterized by vascular endothelial dysfunction (most commonly assessed as impaired endothelium-dependent dilation [EDD]) and stiffening of the large elastic arteries. While various techniques exist to assess EDD and large elastic artery stiffness, the most commonly used are brachial artery flow-mediated dilation (FMDBA) and aortic pulse-wave velocity (aPWV), respectively. Both of these noninvasive measures of vascular dysfunction are independent predictors of future cardiovascular events in patients with and without kidney disease. Patients with CKD demonstrate both impaired FMDBA, and increased aPWV. While the exact mechanisms by which vascular dysfunction develops in CKD are incompletely understood, increased oxidative stress and a subsequent reduction in nitric oxide (NO) bioavailability are important contributors. Cellular changes in oxidative stress can be assessed by collecting vascular endothelial cells from the antecubital vein and measuring protein expression of markers of oxidative stress using immunofluorescence. We provide here a discussion of these methods to measure FMDBA, aPWV, and vascular endothelial cell protein expression.

The degree of vascular dysfunction and contributing physiological mechanisms can be assessed in patients with chronic kidney disease by measuring brachial artery flow-mediated dilation, aortic pulse-wave velocity, and vascular endothelial cell protein expression.

Patients with chronic kidney disease (CKD) have significantly increased risk of cardiovascular disease (CVD) compared to the general population, and this ...

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound and aortic blood pressure is measured invasively with a solid-state pressure catheter. Blood pressure is raised then lowered incrementally by intravenous infusion of vasoactive drugs phenylephrine and sodium nitroprusside. Aortic diameter is measured for each pressure step to characterize the pressure-diameter relationship of the ascending aorta. Stiffness indices derived from the pressure-diameter relationship can be calculated from the data collected. Calculation of arterial compliance is described in this protocol.
This technique can be used to investigate mechanisms underlying increased aortic stiffness associated with cardiovascular disease and aging. The technique produces a physiologically relevant measure of stiffness compared to ex vivo approaches because physiological influences on aortic stiffness are incorporated in the measurement. The primary limitation of this technique is the measurement error introduced from the movement of the aorta during the cardiac cycle. This motion can be compensated by adjusting the location of the probe with the aortic movement as well as making multiple measurements of the aortic pressure-diameter relationship and expanding the experimental group size.

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We describe a technique for measuring aortic stiffness from its pressure-diameter relationship in vivo in mice. Aortic diameter is recorded by ultrasound and aortic pressure is measured invasively with a solid-state pressure catheter. Blood pressure is changed incrementally and the resulting diameter is measured.

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound ...

A Methodological Approach to Non-invasive Assessments of Vascular Function and Morphology

The endothelium is the innermost lining of the vasculature and is involved in the maintenance of vascular homeostasis. Damage to the endothelium may predispose the vessel to atherosclerosis and increase the risk for cardiovascular disease. Assessments of peripheral endothelial function are good indicators of early abnormalities in the vascular wall and correlate well with assessments of coronary endothelial function. The present manuscript details the important methodological steps necessary for the assessment of microvascular endothelial function using laser Doppler imaging with iontophoresis, large vessel endothelial function using flow-mediated dilatation, and carotid atherosclerosis using carotid artery ultrasound. A discussion on the methodological considerations for each of the techniques is also presented, and recommendations are made for future research.

The present article describes the methodological considerations for several non-invasive assessments of vascular function and morphology that are commonly used in medical research to assess different stages of atherosclerosis.

The endothelium is the innermost lining of the vasculature and is involved in the maintenance of vascular homeostasis.  Damage to the endothelium may ...

A Murine Model of Arterial Restenosis: Technical Aspects of Femoral Wire Injury

Cardiovascular disease caused by atherosclerosis is the leading cause of death in the developed world. Narrowing of the vessel lumen, due to atherosclerotic plaque development or the rupturing of established plaques, interrupts normal blood flow leading to various morbidities such as myocardial infarction and stroke. In the clinic endovascular procedures such as angioplasty are commonly performed to reopen the lumen. However, these treatments inevitably damage the vessel wall as well as the vascular endothelium, triggering an excessive healing response and the development of a neointimal plaque that extends into the lumen causing vessel restenosis (re-narrowing). Restenosis remains a major cause of failure of endovascular treatments for atherosclerosis. Thus, preclinical animal models of restenosis are vitally important for investigating the pathophysiological mechanisms as well as translational approaches to vascular interventions. Among several murine experimental models, femoral artery wire injury is widely accepted as the most suitable for studies of post-angioplasty restenosis because it closely resembles the angioplasty procedure that injures both endothelium and vessel wall. However, many researchers have difficulty utilizing this model due to its high degree of technical difficulty. This is primarily because a metal wire needs to be inserted into the femoral artery, which is approximately three times thinner than the wire, to generate sufficient injury to induce prominent neointima. Here, we describe the essential surgical details to effectively overcome the major technical difficulties of this model. By following the presented procedures, performing the mouse femoral artery wire injury becomes easier. Once familiarized, the whole procedure can be completed within 20 min.

The mouse femoral artery wire injury model of restenosis is technically challenging. In this protocol we show the key technical details essential for successfully performing wire injury to induce consistent&#160;neointima for studies of restenosis.

Cardiovascular disease caused by atherosclerosis is the leading cause of death in the developed world. Narrowing of the vessel lumen, due to ...

Ultrasound-based Pulse Wave Velocity Evaluation in Mice

Arterial stiffness can be evaluated by calculating pulse wave velocity (PWV), i.e., the speed with which the pulse wave travels in a conduit vessel. This parameter is being increasingly investigated in small rodent models in which it is used for assessing alterations in vascular function related to particular genotypes/treatments or for characterizing cardiovascular disease progression. This protocol describes an image processing algorithm which leads to non-invasive arterial PWV measurement in mice using ultrasound (US) images only. The proposed technique has been used to assess abdominal aorta PWV in mice and evaluate its age-associated changes.
Abdominal aorta US scans are obtained from mice under gaseous anesthesia using a specific US device equipped with high-frequency US probes. B-mode and Pulse-Wave Doppler (PW-Doppler) images are analyzed in order to obtain diameter and mean velocity instantaneous values, respectively. For this purpose, edge detection and contour tracking techniques are employed. The single-beat mean diameter and velocity waveforms are time aligned and combined in order to achieve the diameter-velocity (lnD-V) loop. PWV values are obtained from the slope of the linear part of the loop, which corresponds to the early systolic phase.
With the present approach, anatomical and functional information about the mouse abdominal aorta can be non-invasively achieved. Requiring the processing of US images only, it may represent a useful tool for the non-invasive characterization of different arterial sites in the mouse in terms of elastic properties. The application of the present technique can be easily extended to other vascular districts, such as the carotid artery, thus providing the possibility to obtain a multi-site arterial stiffness assessment.

Arterial stiffness represents a key factor in cardiovascular disease and pulse wave velocity (PWV) can be considered as a surrogate index for arterial stiffness. This protocol describes an image processing algorithm for calculating PWV in mice based on ultrasound image processing that is applicable at different arterial sites.

Arterial stiffness can be evaluated by calculating pulse wave velocity (PWV), i.e., the speed with which the pulse wave travels in a conduit vessel. This ...

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

The goal of this method is to introduce a transgene into the endothelium of isolated segments of both rabbit common carotid arteries. The method achieves focal endothelial-selective transgenesis, thereby allowing an investigator to determine the biological roles of endothelial-expressed transgenes and to quantify the in vivo transcriptional activity of DNA sequences in large artery endothelial cells. The method uses surgical isolation of rabbit common carotid arteries and an arteriotomy to deliver a transgene-expressing viral vector into the arterial lumen. A short incubation period of the vector in the lumen, with subsequent aspiration of the lumen contents, is sufficient to achieve efficient and durable expression of the transgene in the endothelium, with no detectable transduction or expression outside of the isolated arterial segment. The method allows assessment of the biological activities of transgene products both in normal arteries and in models of human vascular disease, while avoiding systemic effects that could be caused either by targeting gene delivery to other sites (e.g. the liver) or by the alternative approach of delivering genetic constructs to the endothelium by germ line transgenesis. Application of the method is limited by the need for a skilled surgeon and anesthetist, a well-equipped operating room, the costs of purchasing and housing rabbits, and the need for expertise in gene-transfer vector construction and use. Results obtained with this method include: transgene-related alterations in arterial structure, cellularity, extracellular matrix, or vasomotor function; increases or reductions in arterial inflammation; alterations in vascular cell apoptosis; and progression, retardation, or regression of diseases such as intimal hyperplasia or atherosclerosis. The method also allows measurement of the ability of native and synthetic DNA regulatory sequences to alter transgene expression in endothelial cells, providing results that include: levels of transgene mRNA, levels of transgene protein, and levels of transgene enzymatic activity.

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

This method is to introduce a transgene into the endothelium of rabbit carotid arteries. Introduction of the transgene allows the assessment of the biological role of the transgene product either in normal arteries or disease models. The method is also useful for measuring activity of DNA regulatory sequences.

The goal of this method is to introduce a transgene into the endothelium of isolated segments of both rabbit common carotid arteries. The method achieves ...

Using Arterial Stiffness and Endothelial Function for Cardiovascular Assessment

Pulse-Wave Velocity, Flow-Mediated Dilation, and Carotid Intima-Media Thickness to Assess Cardiovascular Risk in Population with Metabolic Syndrome

Pulse-wave velocity (PWV), flow-mediated dilation (FMD), and carotid intima-media thickness (CIMT) are established methods used in research and clinical settings to assess arterial stiffness, endothelial function, and subclinical atherogenesis. These measurements may reflect vascular disease and atherosclerotic progression, which are major causes of adverse cardiovascular events. These methods are particularly valuable in determining cardiovascular dysfunction among populations with different risk factors, such as diabetes mellitus, hypertension, and other metabolic dysfunction-related conditions. They provide a non-invasive and reliable source of information that complements clinical practice. Early detection, risk assessment, and therapeutic decisions regarding cardiovascular disease can be achieved, ultimately contributing to improved patient outcomes. Traditional tools for evaluating cardiovascular disease do not reveal whether metabolic syndrome affects early subclinical cardiovascular disease in patients with obesity. Recent research has highlighted the importance of including arterial stiffness and endothelial function in a comprehensive cardiovascular assessment. Therefore, the aim of the present study is to describe methods that provide information on early subclinical vascular aging, endothelial dysfunction, and atherogenic disease, enabling vascular-targeted risk stratification among populations with obesity and different metabolic profiles.

Author Spotlight: Assessing the Cardiovascular Profile of Patients with Metabolic Syndrome

Endothelial/vascular aging and atherogenesis are key mechanisms that promote the development of cardiovascular diseases. The present protocol describes methods to evaluate arterial stiffness, endothelial dysfunction, and atherogenesis in patients with related risk factors, which are highly valuable in the cardiovascular research field.

Pulse-wave velocity (PWV), flow-mediated dilation (FMD), and carotid intima-media thickness (CIMT) are established methods used in research and clinical ...

Ultrasound Assessment of Aortic and Carotid Artery Intima-media Thickness in Children and Adolescents

Carotid intima-media thickness (IMT), measured using high-resolution B-mode ultrasonography, is a widely utilized surrogate marker of subclinical atherosclerosis, the pathophysiological process underlying most clinical cardiovascular disease events. Atherosclerosis is a gradual disease that originates early in life, thus, there has been increased interest in measuring carotid IMT in childhood and adolescence to assess structural change in the arterial vasculature in response to adverse exposures. However, the timing of atherosclerosis varies across the vascular tree. Primordial atherosclerotic lesions are present in the abdominal aorta as early as infancy, compared to mid-adolescence for the common carotid. Measurement of IMT at either site is susceptible to several technical challenges that need to be considered, especially in younger children. In this paper, we provide a detailed stepwise method for high-quality assessment of IMT of the abdominal aorta and common carotid artery in the young. We also provide insight into the appropriateness of either site when exploring the associations between early-life exposures and later-life cardiovascular disease.

The present article describes the methodological considerations for the noninvasive assessment of abdominal aortic and carotid intima-media thickness using B-mode ultrasonography. This technique is commonly used in the developmental origins of health and disease research as a surrogate for early arterial changes.

Measuring the Carotid to Femoral Pulse Wave Velocity (Cf-PWV) to Evaluate Arterial Stiffness

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The Measurement and Treatment of Suppression in Amblyopia

Pulse Wave Velocity Testing in the Baltimore Longitudinal Study of Aging

Assessment of Vascular Function in Patients With Chronic Kidney Disease

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

A Methodological Approach to Non-invasive Assessments of Vascular Function and Morphology

A Murine Model of Arterial Restenosis: Technical Aspects of Femoral Wire Injury

Ultrasound-based Pulse Wave Velocity Evaluation in Mice

In Vivo Gene Transfer to the Rabbit Common Carotid Artery Endothelium

Pulse-Wave Velocity, Flow-Mediated Dilation, and Carotid Intima-Media Thickness to Assess Cardiovascular Risk in Population with Metabolic Syndrome

Ultrasound Assessment of Aortic and Carotid Artery Intima-media Thickness in Children and Adolescents