Comparison of New Measures of Vascular Function to Flow Mediated Dilatation as a Measure of Cardiovascular Risk Factors

Philpott, Andrew C.; Lonn, Eva; Title, Lawrence M.; Verma, Subodh; Buithieu, Jean; Charbonneau, François; Anderson, Todd J.

doi:10.1016/j.amjcard.2009.01.376

Cited by 64 publications

(73 citation statements)

References 26 publications

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“…Is an endothelium-dependent stimulus that elicits the production of a range of vasodilators more prognostically relevant than one that is more unimodal? On the latter question, there is already evidence that measures such as the blood flow or shear stress response after cuff release, indicators of microvascular function, 45,46 possess independent predictive value, 47,48 and such responses are not NO mediated. Ultimately, answers to these questions will require data from a prospective randomized trial of different stimuli derived from the same subjects.…”

Section: Does Fmd Predict Cardiovascular Events Because It Is a Surromentioning

confidence: 99%

Flow-Mediated Dilation and Cardiovascular Event Prediction

et al. 2011

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Abstract-Endothelial dysfunction is an early atherosclerotic event that precedes clinical symptoms and may also render established plaque vulnerable to rupture. Noninvasive assessment of endothelial function is commonly undertaken using the flow-mediated dilation (FMD) technique. Some studies indicate that FMD possesses independent prognostic value to predict future cardiovascular events that may exceed that associated with traditional risk factor assessment. It has been assumed that this association is related to the proposal that FMD provides an index of endothelium-derived nitric oxide (NO) function. Interestingly, placement of the occlusion cuff during the FMD procedure alters the shear stress stimulus and NO dependency of the resulting dilation: cuff placement distal to the imaged artery leads to a largely NO-mediated response, whereas proximal cuff placement leads to dilation which is less NO dependent. We used this physiological observation and the knowledge that prognostic studies have used both approaches to examine whether the prognostic capacity of FMD is related to its role as a putative index of NO function. In a meta-analysis of 14 studies (Ͼ8300 subjects), we found that FMD derived using a proximal cuff was at least as predictive as that derived using distal cuff placement, despite the latter being more NO dependent. This suggests that, whilst FMD is strongly predictive of future cardiovascular events, this may not solely be related to its assumed NO dependency. Although this finding should be confirmed with more and larger studies, we suggest that any direct measure of vascular (endothelial) function may provide independent prognostic information in humans. Cost-effective prevention of cardiovascular disease (CVD) is predicated on cardiovascular risk assessment, which aims to distinguish between individuals at high and low risk of future disease manifestation. An optimal screening method should be inexpensive, relatively noninvasive and reproducible. It should predict risk in patients with known disease and, ideally, the future risk of events in currently healthy asymptomatic populations. 1 Despite several decades of development and refinement, algorithms for the prediction of cardiovascular risk in humans that are based on "traditional" or "conventional" risk factors fail to predict a substantial proportion of cardiovascular events. 1 A recent review pertaining to identification of the "vulnerable patient" concluded that high Framingham risk scores fall short in accurately predicting events in individual patients and cannot provide a clear clinical route for identification or treatment of near future victims of acute coronary syndrome or sudden death. 1 A recent computed tomography angiographic study of 1650 subjects concluded that only 55% of patients with a high plaque burden had high National Cholesterol Education Program/Framingham risk scores. Of the patients identified as high risk by Framingham in this study, 10% had no evidence of plaque, 32% with no plaque were taking statins based on t...

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Section: Does Fmd Predict Cardiovascular Events Because It Is a Surromentioning

confidence: 99%

Flow-Mediated Dilation and Cardiovascular Event Prediction

et al. 2011

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“…[102][103][104] It is now widely accepted that chronic constriction of the blood vessels, particularly at the level of the resistance vessels, results in locally damaging increases in blood flow velocity and turbulence that can increase shear stress, damage the endothelium and produce maladaptive remodeling of the vasculature. [105][106][107] Indeed, Rizzoni et al 108 reported that such structural alterations in the small arteries represent the most potent predictor for CVD in the hypertensive population. Less is known about the effects of intermittent or episodic hypertension per se.…”

Section: Abnormal Blood Pressure and Structural Alterations In The Vamentioning

confidence: 99%

Peripheral vascular function in spinal cord injury: a systematic review

et al. 2012

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Background: During the past 20 years, significant advances in patient care have resulted in individuals with spinal cord injury (SCI) living longer than before. As lifespan increases, cardiovascular complications are emerging as the leading cause of mortality in this population, and individuals with SCI develop cardiovascular disease at younger ages than their able-bodied counterparts. To address this increasing clinical challenge, several recent studies investigated the central cardiovascular adaptations that occur following SCI. However, a somewhat less recognized component of cardiovascular dysfunction in this population is the peripheral vascular adaptations that also occur as a result of SCI. Study design: Literature review.Objective: To present a comprehensive overview of changes in arterial structure and function, which occur after SCI. Setting: Canada. Methods: A systematic literature review was conducted to extract studies that incorporated measures of arterial structure or function after SCI in animals or humans. Results: Individuals with SCI exhibit vascular dysfunction below the lesion that is characterized by a reduction in conduit artery diameter and blood flow, increased shear rate and leg vascular resistance, and adrenoceptor hyper-responsiveness. There is also recent alarming evidence for central arterial stiffening in individuals with SCI. Conclusion: Although physical deconditioning is the primary candidate responsible for the maladaptive remodeling of the peripheral vasculature after SCI, there is emerging evidence that blood pressure oscillations, such as those occurring in the large majority of individuals with SCI, also exacerbates vascular dysfunction in this population.

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“…Although VTI has been shown to be more closely related to cardiac risk factors than FMD, as well as an independent predictor of cardiovascular events, the optimal VTI end point to measure the effect remains unclear. 8,11 The purpose of this study was to determine whether the VTI of more than one beat of reactive hyperaemia provides better diagnostic validity than the first hyperaemic beat. vascular health of every subject was evaluated through ultrasound of the brachial artery.…”

Section: Introductionmentioning

confidence: 99%

The optimal measure of microvascular function with velocity time integral for cardiovascular risk prediction

et al. 2012

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Methods Study population and study designThis study included 399 male subjects, a subset of the Firefighters and Their Endothelium (FATE) study cohort. The FATE study protocol has been described previously. 12 Briefly, all subjects were assessed for cardiovascular risk factors through physical examination and blood work. TheThe optimal measure of microvascular function with velocity time integral for cardiovascular risk prediction Vincent Lee, Billie-Jean Martin, Marinda Fung and Todd J Anderson Abstract Recent evidence suggests that microvascular function may be important in cardiovascular risk prediction. One measure of microvascular function is hyperaemic velocity time integral (VTI). We assessed whether the VTI of more than one beat of reactive hyperaemia would provide a stronger correlate to traditional cardiovascular risk factors using a subset of subjects from the Firefighters and Their Endothelium (FATE) study. Vascular function was assessed by measurement of hyperaemic blood velocity with high-resolution ultrasound of the brachial artery. We evaluated three measures in the current analysis: the VTI of the first beat, average VTI of 10 beats, and maximum VTI of 10 beats post-cuff release. A total of 399 male subjects (45.5 ± 10 years) were included in this analysis. Univariate correlations between the three end points and cardiovascular risk factors were calculated, and multivariable regression models constructed. Intra-observer variability was approximately equal for all VTI end points (coefficient of variation: first = 1.6%, average = 1.4%, maximum = 1.4%). Univariate correlations between VTI and cardiovascular risk factors were similar across all three end points. In multivariable analyses, there were no differences in the relationships between cardiovascular risk factors and the various VTI end points (R 2 from 0.090 to 0.102). Age, systolic blood pressure, and BMI were predictors of the three VTI end points (p < 0.05). In conclusion, the first beat of reactive hyperaemia remains the suitable measure of microvascular function.

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Comparison of New Measures of Vascular Function to Flow Mediated Dilatation as a Measure of Cardiovascular Risk Factors

Cited by 64 publications

References 26 publications

Flow-Mediated Dilation and Cardiovascular Event Prediction

Flow-Mediated Dilation and Cardiovascular Event Prediction

Peripheral vascular function in spinal cord injury: a systematic review

The optimal measure of microvascular function with velocity time integral for cardiovascular risk prediction

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