Measure Of Aortic Stiffness Research Articles

The relation of red blood cell fatty acids with vascular stiffness, cardiac structure and left ventricular function: the Framingham Heart Study.

Polyunsaturated fatty acids have been associated with beneficial influences on cardiovascular health. However, the underlying mechanisms are not clear, and data on the relations of polyunsaturated fatty acids to subclinical disease measures such as vascular stiffness and cardiac function are sparse and inconclusive. In a large community-based cohort, we examined the relations of omega-3 and other fatty acids to a comprehensive panel of vascular function measures (assessing microvascular function and large artery stiffness), cardiac structure and left ventricular function. Red blood cell (RBC) membrane fatty acid composition, a measure of long-term fatty acid intake, was assessed in participants of the Framingham Offspring Study and Omni cohorts and related to tonometry-derived measures of vascular stiffness and to a panel of echocardiographic traits using partial correlations. Up to n=3055 individuals (56% women, mean age 66 years) were available for analyses. In age- and sex-adjusted models, higher RBC omega-3 content was moderately associated (p≤0.002) with several measures of vascular stiffness and function in a protective direction. However, after multivariable adjustment, only an association of higher RBC omega-3 content with lower carotid-femoral pulse wave velocity (a measure of aortic stiffness) remained significant (r = -0.06, p=0.002). In secondary analyses, higher linoleic acid, the major nutritional omega-6 fatty acid, was associated with smaller left atrial size, even after multivariable adjustment (r = -0.064, p<0.001). In conclusion, in our cross-sectional community-based study, we found several associations consistent with the notion of protective effects of omega-3 and linoleic acid. The clinical significance of these modest associations remains to be elucidated.

Sex differences in noninvasive estimates of left ventricular pressure energetics but not myocardial oxygen demand in young adults

BackgroundSex differences in arterial stiffness and wave reflections may lead to disproportionate increases in afterload and myocardial work in women. We examined sex differences in arterial stiffness, pressure from wave reflections, measures of left ventricular (LV) energetics and myocardial work. Methods99 Healthy adults participated in this study 84 were selected (42 females, 42 males) to be matched for potential confounders of central hemodynamic burden such as age, BMI, and mean arterial pressure. Aortic pressure waves were derived from the radial artery using a generalized transfer function. Pulse contour analysis and wave separation analysis were used to obtain: pulse wave velocity (PWV) as a measure of aortic stiffness, augmentation index (AIx) and reflection index (RIx) as measures of global wave reflections, LV pressure effort (ΔEw) as a measure of LV energy required to overcome wave reflections and the subendocardial viability ratio (SEVR) as a proxy of myocardial work. ResultsWomen exhibited higher ΔEw (p < 0.05), heart rate corrected AIx (p < 0.05) and RIx (p < 0.01), and lower PWV (p < 0.001) compared to men. Pressure from wave reflections (Pb) was significantly associated with ΔEw in women (r = 0.81, p < 0.001), but not in men (r = 0.14, p > 0.05). There were no sex differences for SEVR (p = 0.4). ConclusionWomen had higher pressure from wave reflections which was associated with greater LV pressure effort compared to men. Although women had increased LV pressure effort, proxies of myocardial perfusion and work were not affected.

Use and limitations of Cardiac Magnetic Resonance derived measures of aortic stiffness in patients after acute myocardial infarction

IntroductionCardiac magnetic resonance (CMR) is a unique method to determine regional and local aortic stiffness parameters. Although various methods have been validated, there are no data in patients after acute ST-segment elevation myocardial infarction (STEMI). In the present study we assessed the feasibility of different CMR derived measures of aortic stiffness in patients after first acute STEMI for the first time. MethodsCMR derived aortic pulse wave velocity (PWV) determined by the regional transit-time (PWVTT) and local flow-area (PWVQA) method as well as local distensibility coefficients (DCs) was analyzed in 22 healthy young volunteers and 28 patients with recent acute STEMI. ResultsPWVTT and DC of the ascending aorta differed significantly between healthy subjects and STEMI patients (all p<0.001). PWVQA at thoracic levels of aorta was not different between groups (p>0.520) and did not correlate with age (p>0.149) and PWVTT (p>0.310). Intra- and interobserver variability was high for PWVTT (r=0.970, p<0.001 and r=0.920, p<0.001), acceptable for DC (all r>0. 809, p<0.001 and all r>0.510, p<0.001) but low for thoracic PWVQA (all r<0.330 and all r<0.372). ConclusionPWVTT and local DC are robust methods for the assessment of aortic stiffness in patients after acute STEMI.

Aortic stiffness and interstitial myocardial fibrosis by native T1 are independently associated with left ventricular remodeling in patients with dilated cardiomyopathy.

Increased aortic stiffness is related to increased ventricular stiffness and remodeling. Myocardial fibrosis is the pathophysiological hallmark of failing heart. We investigated the relationship between noninvasive imaging markers of myocardial fibrosis, native T1, and late gadolinium enhancement, respectively, and aortic stiffness in ventricular remodeling. Consecutive patients with known dilated cardiomyopathy (n=173) underwent assessment of cardiac volumes and function, T1 mapping, scar imaging, and pulse wave velocity, a measure of aortic stiffness. Asymptomatic healthy volunteers served as controls (n=47). Controls and patients showed an increase in pulse wave velocity with age, which was accelerated in the presence of cardiovascular disease. On the contrary, native T1 increased with age in patients, but not in controls. Pulse wave velocity was associated with native T1 in the presence of disease, but not in health. Native T1 showed a strong relationship with markers of structural and functional left ventricular remodeling and diastolic impairment. Ischemic and nonischemic pathophysiology of ventricular remodeling showed a similar slope of relationship between pulse wave velocity and native T1. However, in nonischemic patients, increase in pulse wave velocity was associated with greater increase in native T1. Aortic stiffness is related to age, and this process is accelerated in the presence of disease. On the contrary, increase in interstitial myocardial fibrosis is associated with age in the presence of disease. Patients with ischemic and nonischemic dilated cardiomyopathy have a similar relationship between native T1 and pulse wave velocity, which is stronger in the latter group.

X chromosome parental origin and aortic stiffness in turner syndrome.

Aortic abnormalities contribute to increased morbidity and mortality of women with Turner syndrome (TS). Impaired aortic stiffness may prove to have clinical prognostic value in TS as is the case in other diseases such as Marfan syndrome, diabetes and hypertension. Additionally, the parental origin of the X chromosome in TS may influence aortic stiffness. To assess the relation between X chromosome parental origin and aortic stiffness in TS patients. Twenty-four subjects with TS participated in this cross-sectional study at a tertiary care centre. The parental origin of the X chromosome was determined. Cardiac-gated multidetector computerized tomography (MDCT) was performed and distensibility of the ascending aorta (AA), a measure of aortic stiffness, was calculated. Fourteen women were Xm (maternal origin) and 10 were Xp (paternal origin) for their inheritance of the single X chromosome. Age, body size, blood pressure and AA areas were similar in the two groups. However, the calculated AA distensibility was significantly lower in the Xm group (2·8 ± 1·1 mm/Hg) than in the Xp group (4·1 ± 1·5 mm/Hg); P < 0·05. Conclusion This study demonstrates that TS subjects that inherit their single X chromosome from their mother (Xm) have a significantly stiffer aorta compared with the TS with a paternally originating X chromosome (Xp), consistent with a potentially greater risk for cardiovascular complications. These findings suggest that parental chromosomal analysis and aortic stiffness measurements would be useful for the risk assessment and clinical management of TS patients.

Aortic stiffness is an indicator of cognitive dysfunction before and after aortic valve replacement for aortic stenosis

Post-cardiac surgical cognitive dysfunction occurs more commonly following valvular procedures. Cognitive function has been related to vascular health status; however, the relation between pre-existent arterial stiffness and perioperative cognitive dysfunction is yet to be defined. The objective of this study was to assess whether aortic stiffness is related to cognitive dysfunction in surgical aortic stenosis (AS) pre- and postoperatively. Between June 2010 and August 2012, patients undergoing aortic valve replacement (AVR) for AS were recruited for inclusion in this prospective observational study. Aortic pulse wave velocity (PWV) was used as a measure of aortic stiffness and cognitive function was assessed using the computerized Cambridge Neuropsychological Test Automated Battery (CANTAB) preoperatively and (409 ± 159 days) post-AVR. Fifty-six patients (age 71 ± 8.4 years) were recruited. Of the total, 50 (89%) completed postoperative follow-up. Pre- and postoperatively, patients with normal PWV (PWV-norm) had significantly superior delayed memory, sustained visual attention and executive function compared with those with high PWV (PWV-high). Immediate memory and decision-making were similar between groups. Postoperatively, improvement in cognitive function was more marked in PWV-high compared with PWV-norm patients. In two models of multiple regression analysis, PWV as a continuous variable was independently related to all preoperative main cognitive components as well as postoperative executive function. PWV as a dichotomous variable was independently related to all pre- and postoperative main cognitive function components. AVR may not be associated with an independent or homogeneous effect on cognitive decline. Aortic PWV might be useful as an additional indicator for cognitive dysfunction before and after surgical intervention for AS.

Relation of Systolic, Diastolic, and Pulse Pressures and Aortic Distensibility With Atrial Fibrillation (from the Multi-Ethnic Study of Atherosclerosis)

Previous research suggests that elevated pulse pressure (PP) is a risk factor for atrial fibrillation (AF) independently of mean arterial pressure (MAP). PP may serve as an indirect measure of aortic stiffness (reduced distensibility), but whether directly measured aortic distensibility is related to risk for AF has not yet been studied. This analysis included 6,630 participants aged 45 to 84years from the Multi-Ethnic Study of Atherosclerosis. At baseline, blood pressure and other relevant covariates were measured using standardized protocols. Magnetic resonance imaging-based aortic distensibility was measured in 3,441 participants. Incident AF was identified from hospitalization discharge codes and Medicare claims. Multivariate Cox models were used to estimate the association of blood pressure components and aortic distensibility with AF risk. During a mean follow-up of 7.8years, 307 AF events (137 among those with aortic distensibility measurements) were identified. In multivariate-adjusted models simultaneously including MAP and PP, each 1-SD increase in PP was associated with a 29% increased risk of AF (95% confidence interval 5% to 59%, p= 0.02), with MAP not being associated with increased AF risk. Overall, aortic distensibility was not consistently associated with AF risk: after removing outliers, each 1-SD increase in aortic distensibility was associated with a 9% increased risk of AF (95% confidence interval-22% to 51%, p= 0.63). In conclusion, in this large community-based cohort, we found that PP, but not MAP or aortic distensibility, was a significant risk factor for AF, emphasizing the importance of PP when assessing the risk for developing AF. Our results cast doubt on the clinical utility of aortic distensibility as a predictor for the development of AF.

Arterial stiffness and hypertension: chicken or egg?

Hypertension is highly prevalent in the United States and worldwide. In the United States, 1 in 3 adults (≈73 million people) have hypertension. The financial and human costs of hypertension are substantial. The estimated costs attributable to hypertension in the United States alone in 2010 were $70 billion direct costs for medical treatments and $24 billion indirect costs because of lost productivity.1 Awareness and treatment of hypertension have improved considerably during the past several decades: >80% of all people with hypertension are aware of the condition and 75% are using antihypertensive medications.2,3 However, despite enormous effort and treatment-related expenditures, only 53% of those with documented hypertension have their blood pressure controlled.3 Older age (Figure 1), left ventricular hypertrophy, and obesity are important risk factors for uncontrolled or drug-resistant hypertension.4 Importantly, the foregoing are also risk factors for increased aortic stiffness.5 Figure 1. Hypertension prevalence and control rates as a function of age in the National Health and Nutrition Examination Survey 2003 to 2004. Data derived from Wong et al.44 During the past 2 decades, measures of aortic stiffness have emerged as important risk factors for progression of blood pressure and incident cardiovascular disease. Carotid femoral pulse wave velocity (CFPWV), a measure of aortic wall stiffness, increases markedly with age, particularly after midlife. For example, Framingham Heart Study investigators have shown that the prevalence of CFPWV ≥12 m/s increases from a few percentage before 50 years of age to ≥60% after 70 years of age (Figure 2A). Importantly, elevated CFPWV is associated with high risk for incident hypertension (Figure 2B) and cardiovascular disease (Figure 2C). Figure 2C should be interpreted within the context that a normal value (<95th percentile) for CFPWV in a healthy Framingham Heart Study reference sample <50 years of age was 8.1 …

Large artery stiffness and carotid flow pulsatility in stroke survivors

Aortic stiffness is increased in lacunar stroke. The precise mechanism linking aortic stiffness to symptomatic lacunar stroke is not well understood. The aim of this study was to compare the effects of aortic stiffness, carotid stiffness, central blood pressure, and cerebrovascular resistance on carotid flow pulsatility according to stroke subtype. Two hundred and one consecutive patients were examined 13 months after hospitalization for their first-ever ischemic stroke. The stroke subtype was classified using the Causative Classification of Stroke System. Carotid-femoral pulse wave velocity (PWV) was used as a measure of aortic stiffness. Common carotid flow pulsatility was expressed as resistive index. Central blood pressure was measured using applanation tonometry. Complete data were available for 174 patients (mean age… 67 ± 10 years, 64% men). In patients with lacunar stroke, aortic PWV was higher (13.11 ± 2.74 m/s) than in individuals with large artery atherosclerosis (9.98 ± 1.87 m/s, P <0.001), cardioembolic (11.31 ± 3.18 m/s, P = 0.04) or cryptogenic stroke (11.13 ± 3.2 m/s, P = 0.01). Similarly, central SBP and resistive index were higher in patients with lacunar stroke (145 ± 23 mmHg and 0.80 ± 0.04, respectively) than those with large artery atherosclerosis (128 ± 18 mmHg, P <0.01 and 0.74 ± 0.07, P <0.01, respectively) or cryptogenic stroke (132 ± 18 mmHg, P <0.01 and 0.76 ± 0.07, P <0.05, respectively). In multivariate analysis, aortic stiffness and central pulse pressure were the main determinants of resistive index independent of stroke subtype. Our results suggest that aortic stiffening, by reducing the buffering function of the aorta and thereby increasing the transmission of pressure and flow pulsatility into the cerebral arterioles, may contribute to the pathogenesis of lacunar stroke.

Arterial stiffness and hypertension.

Over the past decade, increased aortic stiffness has emerged as an important risk factor for target organ damage and cardiovascular disease events. Aortic stiffness can be assessed as pulse wave velocity (PWV), which is a measure of aortic wall stiffness, and pulse pressure (PP), which is affected by wall stiffness and the interaction between flow and diameter. Because these stiffness measures have different sensitivities to geometry and other factors, they are only moderately correlated and play a complementary role in risk prediction. Arterial stiffness has long been viewed as a complication of hypertension that integrates long-term adverse effects of elevated blood pressure and other risk factors. However, PWV is only modestly correlated with risk factors other than age and blood pressure, which likely explains the ability of PWV to add to standard risk prediction models and reclassify risk in a clinically relevant manner. Recent studies have demonstrated that stiffness can antedate and contribute to the pathogenesis of hypertension, raising the possibility that early assessment of arterial stiffness may provide insight into complications including hypertension that develop years later. The role that stiffness plays in the pathogenesis of hypertension and cardiovascular disease has sparked considerable interest in defining basic mechanisms that stiffen the aortic wall, increase PP and contribute to target organ damage with a hope that elucidation of these mechanisms will allow for development of more effective treatments.

Association of pulsatile and mean cerebral blood flow velocity with age and neuropsychological performance

Low cerebral blood flow velocity is associated with cognitive decline. However, the association between pulsatile brain blood flow velocity and cognition has not been investigated. High pulsatile hemodynamic stress in the brain may impair cognitive function through damage to small cerebral vessels. The current objective was to examine the cross-sectional association of pulsatile and mean cerebral blood flow velocity with age and neuropsychological performance. We also examined whether cerebral blood flow velocity was associated with aortic pulse pressure, a measure of arterial ageing and aortic stiffness. Cerebral blood flow velocity was measured in the middle cerebral artery using Transcranial Doppler Ultrasonography (TDU) while neuropsychological performance was measured using a computerized cognitive test battery. Aortic pulse pressure was non-invasively derived from applanation tonometry of the radial artery. The sample comprised 160 healthy adults aged 50–70years. Results indicated that increasing age correlated with lower mean (r=−0.23, p<0.01) and higher pulsatile (r=0.27, p<0.01) brain blood flow velocity. In multivariate adjusted models, both peripheral (β=0.28, p<0.05) and aortic (β=0.24, p<0.05) pulse pressure were associated with higher pulsatile flow velocity through the middle cerebral artery. In adjusted models, neither mean nor pulsatile cerebral blood flow velocity was associated with performance on any cognitive task. In conclusion, arterial ageing was associated with increased pulsatile hemodynamic stress in the brain. However, this was not associated with impaired neuropsychological performance.

Cardiovascular aging: Insights from local and regional measures of aortic stiffness using magnetic resonance imaging

Aortic stiffness is now established as an independent marker of cardiovascular aging and cardiovascular risk. However, the specific role of the proximal aorta, specifically the ascending aorta, remains understudied. Magnetic resonance imaging (MRI), a non-invasive technique has recently been proposed to measure new local and regional imaging biomarkers of stiffness in the thoracic aorta. We will here review recent data on aortic stiffness assessed by MRI. We will discuss the methodological advantages and challenges of MRI, combined with applanation tonometry, to evaluate local aortic distensibility and pulse wave velocity (PWV) and summarize available results concerning the age related distribution of such parameters.Aortic distensibility has been shown to be an early subclinical marker of vascular target organ damage in the general population and expected ranges for ascending aortic distensibility and aortic arch pulse wave velocity assessed in MRI have been described. Changes in aortic distensibility and arch PWV have been related to age-related geometric changes, specifically lengthening, enlargement and unfolding of the thoracic aorta. Increased proximal aortic stiffness measured by MRI has also been related to decreased systolic and diastolic function and concentric remodeling of the left ventricule in healthy individuals.

Arterial Stiffness in Patients with Ischemic Attack

Dear Editor, we read the article ‘Aortic stiffness measurement improves the prediction of asymptomatic coronary artery disease (CAD) in stroke/transient ischemic attack patients’ by Calvet and coworkers with a great interest (1). They investigated the predictive value of aortic stiffness for >50% asymptomatic CAD in a stroke/transient ischemic attack population. They concluded that in stroke/ transient ischemic attack patients, aortic pulse wave velocity improves the prediction of >50% asymptomatic CAD beyond classical risk factors. We believe that these findings will be guides for further studies about the effect of inflammation on arterial stiffness parameters in patients with stroke/transient ischemic attack. Endothelial dysfunction is the critical early step in the process of atherogenesis, and it is commonly investigated by measuring arterial stiffness (2,3). Increased arterial stiffness is a common indicator of atherosclerotic involvement of the vascular structure indicating CAD, cerebrovascular disease, peripheral arterial disease, and hypertension. Also, arterial stiffness parameters can reflect the inflammatory diseases. In a previous study, we investigated the relationship between arterial stiffness and highsensitivity C-reactive protein (hsCRP) in patients with psoriasis. We concluded that arterial stiffness parameters were higher and correlated positively with age, gender, body mass index, diastolic blood pressure, and hsCRP level in patients with psoriasis (4). Furthermore, some medications such as antihypertensive treatment, including angiotensin-converting enzyme inhibitors, angiotensin receptor blocker, statins used, may influence arterial stiffness parameters. However, the authors of the present study did not mention some factors affecting arterial stiffness parameters. Arterial stiffness parameters can also be affected by the atherosclerotic risk factors such as smoking, alcohol consumption, hypercholesterolemia, hypothyroidism, and older age. Smoking is a modifiable one among the cardiovascular risk factors. In a previous study the authors conducted in 554 hypertensive patients, including active smokers, quitters, and never smoked individuals, the effect of smoking on arterial stiffness were investigated and they showed that arterial stiffness parameters were significantly higher in the smoking patients compared with those of the nonsmokers (5). Hypothyroidism plays a key role in cardiovascular disease pathogenesis by increasing total peripheral vascular resistance and inflammatory condition (6). Previously, the authors demonstrated increases in arterial stiffness parameters in hypothyroid patients (7). The fact is that arterial stiffness is a noninvasive method to assess endothelial dysfunction in clinical practice and that without other inflammatory markers, arterial stiffness alone may not provide information to clinicians about the predictive asymptomatic CAD in patients with stroke/transient ischemic attack. It would have been better if these factors were included in the paper.

Improved pulse wave velocity wave front detection by template-matching

Background Pressure waves distributed through the aorta by left ventricular contraction propagate at a rate known as the pulse wave velocity (PWV). PWV is a measure of aortic stiffness, and increased PWV has been correlated with increased coronary artery disease risk. PWV can be measured by velocity-encoded magnetic resonance (PCMR), with velocity profiles collected at a minimum of two locations along the vessel. The commonly used simple linear regression method computes PWV from detected wavefronts in each profile and distance along the aorta. Recognizing the limitation imposed on wave front detection by simple maximum impulse by noise in the signal producing local maxima, we designed and tested a template-matching scheme to improve PWV estimation. Methods In vivo CMR was performed on a 3T scanner (Verio, Siemens Healthcare) in perimenopausal women with a variable number of atherosclerosis risk factors but no evident atherosclerotic disease. The derivation cohort consisted of 12 scans (4 patients over 3 time points) and validation cohort consisted of 139 scans PC-MR was acquired in an oblique sagittal plane through the descending aorta with in-plane velocity encoding in the head-foot direction and prospective ECG triggering (TE/ TR2.1/9.15 ms, Venc 150 cm/s, flip angle 15°). Distance from the base of the aorta and velocity were collected along the centerline of the aorta. Wave detection was performed at each cross section by the following scheme. A generalized logistic function f(a,t) = -Vmax +2Vmax/[1+exp{-a(t-c)}], c = tmax+ln(1/.99-1)/a, the center point, where Vmax is the maximum velocity, t is time, tmax is the time of the observed Vmax, and a was optimized to maximize the goodness of fit between the template and observed data between c and tmax. An example fit varying the control parameter, a, is shown in Figure 1. Pulse wave velocity was then calculated using simple linear regression over the (c, distance) pairs collected along the aorta. A one-tailed Student t-test with a of .05 was used to test for a significant increase in goodness of fit.

CMR-derived aortic stiffness is associated with more rapid aortic dilation and surgical replacement in children and young adults with connective tissue disorders

Background Aortic stiffness measures have been proposed as novel indicators of disease severity in patients with connective tissue disorders (CTD). However, these measures have not been studied extensively in children. Their relationship to adverse aortic outcomes in this population is also unknown. We studied CMR parameters of aortic stiffness in children and young adults with CTD and assessed their relationship with the rates of aortic dilation and surgical root replacement.

Increased epicardial adipose tissue thickness is linked to aortic stiffness in patients with primary hypertension

Aims. In patients with hypertension (HT), increased aortic stiffness is related to higher cardiovascular morbidity and mortality. Recent investigations have shown that epicardial adipose tissue (EAT) is a new potential cardiometabolic risk factor. The aim of our study was to examine the relation between echocardiographically measured EAT thickness and aortic stiffness in patients with primary HT. Methods. The study included 144 newly diagnosed and untreated essential hypertensive outpatients. Transthoracic echocardiographic EAT thickness and aortic stiffness measurements were performed for all study participants. Afterwards patients were divided in two groups according to their median EAT thickness values. The patients with EAT thickness of < 7 mm were included in group 1 and patients with EAT thickness of ≥ 7 mm were included in group 2. Results. Aortic strain and distensibility parameters of group 2 were lower than in group 1. The aortic stiffness index of group 2 was found to be higher than group 1. Multivariate regression analysis revealed that EAT thickness was the only independent variable for all three parameters of aortic stiffness index, aortic strain and aortic distensibility. Conclusion. In patients with newly diagnosed primary HT, increased EAT thickness was significantly linked to impaired aortic elastic properties independently of other conventional adiposity measurements.

Relation of plasma adiponectin levels and aortic stiffness after acute ST-segment elevation myocardial infarction

Pulse wave velocity is a measure of aortic stiffness and an independent predictor of cardiovascular morbidity and mortality. Adiponectin is involved in atherosclerosis and inflammation. In the present study we aimed to explore the association between plasma adiponectin concentrations and pulse wave velocity in the acute phase after ST-segment elevation myocardial infarction (STEMI). Forty-six consecutive STEMI patients (mean age 57 ± 11 years) treated with primary percutaneous coronary intervention (PCI) were enrolled in this cross-sectional study. Plasma adiponectin was measured 2 days after index event by enzyme-linked immunosorbent assay. Aortic pulse wave velocity (PWV) was calculated by the transit-time method with the use of a velocity-encoded, phase-contrast cardiac magnetic resonance protocol. Median plasma adiponectin concentration was 2385 ng/ml (interquartile range 1735-5403). Males had lower plasma adiponectin values than females and current smokers had lower values than non-smokers (all p<0.02). Adiponectin was significantly associated with PWV (r=0.505, p<0.001), age (r=0.437, p=0.002), and total cholesterol (r=0.468, p=0.001). Multiple linear regression analysis revealed adiponectin as a predictor of PWV independently of age, sex, smoking status, total cholesterol, and N-terminal pro-B-type natriuretic peptide (p=0.027). Plasma adiponectin concentrations are strongly associated with aortic stiffness in patients after acute STEMI treated with primary PCI. Our data support a possible role for adiponectin as an independent risk marker for increased aortic stiffness in STEMI patients.

Abstract 18780: Diminished Left Ventricular Myocardial Oxygen Demand During Dobutamine Stress Testing in the Elderly Reduces the Appearance of Inducible Wall Motion Abnormalities Indicative of Ischemia

Background: It has been observed that dobutamine stress may be less sensitive in the elderly and in those with LVH. We hypothesized that, in the elderly, a reduced increment in myocardial oxygen demand with dobutamine produces false negative results. Methods: We prospectively performed dobutamine cardiovascular magnetic resonance (DCMR) on 276 consecutively recruited individuals aged 55-85 years with risk factors for CAD. Rate pressure product (RPP), assessment of LV wall motion and volumes, aortic pulse wave velocity (PWV a measure of aortic stiffness) and first pass gadolinium enhanced LV perfusion defects (PD) indicative of ischemia were obtained on a 1.5T scanner at rest and after dobutamine infused to achieve 80% of the maximum predicted heart rate. Myocardial oxygen demand was assessed by the systolic pressure volume area (PVA), measured as LV stroke work (SW), [mean arterial pressure * stroke volume] plus potential energy [(1/2*end-systolic pressure) * end-systolic volume]}. All measures were assessed independently by personnel blinded to other data or participant identifiers. Differences were assessed with t-test; p &lt; 0.05 was significant. DCMR PD was considered as the gold standard for the detection of ischemia. Results: Participants averaged 68±8 years, were 80% white, 90% hypertensive, 43% diabetic and 55% men; all achieved target heart rate. With dobutamine, RPP increased 85% and LV end-diastolic volume index decreased. No subject had an inducible WMA without concomitant PD, but 28 had PD without inducible WMA (Table). In these false negatives, PVA was significantly lower (p= 0.03) and LVSW (p = 0.06) and PWV (p= 0.13) had strong trends toward being lower. The sensitivity of DCMR WMA for identifying PD indicative of ischemia was 33%. Conclusion: With dobutamine stress testing, the elderly had declines in LV preload and PVA. These findings provide a novel mechanistic explanation of why the elderly may have false negative wall motion during dobutamine stress.

Reservoir and excess pressures predict cardiovascular events in high-risk patients

BackgroundAnalysis of the arterial pressure curve plays an increasing role in cardiovascular risk stratification. Measures of wave reflection and aortic stiffness have been identified as independent predictors of risk. Their determination is usually based on wave propagation models of the circulation. Another modeling approach relies on modified Windkessel models, where pressure curves can be divided into reservoir and excess pressure. Little is known of their prognostic value. Methods and resultsThe aim of this study is to evaluate the predictive value of parameters gained from reservoir theory applied to aortic pressure curves in a cohort of high-risk patients. Furthermore the relation of these parameters to those from wave separation analysis is investigated.Central pressure curves from 674 patients with preserved ejection fraction, measured by radial tonometry and a validated transfer function, were analyzed. A high correlation between the amplitudes of backward traveling pressure waves and reservoir pressures was found (R=0.97). Various parameters calculated from the reservoir and excess pressure waveforms predicted cardiovascular events in univariate Cox proportional hazards modeling. In a multivariate model including several other risk factors such as brachial blood pressure, the amplitude of reservoir pressure remained a significant predictor (HR=1.37 per SD, p=0.016). ConclusionsBased on very different models, parameters from reservoir theory and wave separation analysis are closely related and can predict cardiovascular events to a similar extent. Although Windkessel models cannot describe all of the physiological properties of the arterial system, they can be useful to analyze its behavior and to predict cardiovascular events.

Hemodynamic and arterial stiffness differences between African-Americans and Caucasians after maximal exercise.

African-American (AA) men have higher arterial stiffness and augmentation index (AIx) than Caucasian-American (CA) men. Women have greater age-associated increases in arterial stiffness and AIx than men. This study examined racial and sex differences in arterial stiffness and central hemodynamics at rest and after an acute bout of maximal exercise in young healthy individuals. One hundred young, healthy individuals (28 AA men, 24 AA women, 25 CA men, and 23 CA women) underwent measurements of aortic blood pressure (BP) and arterial stiffness at rest and 15 and 30 min after an acute bout of graded maximal aerobic exercise. Aortic BP and AIx were derived from radial artery applanation tonometry. Aortic stiffness (carotid-femoral) was measured via pulse wave velocity. Aortic stiffness was increased in AA subjects but not in CA subjects (P < 0.05) after an acute bout of maximal cycling exercise, after controlling for body mass index. Aortic BP decreased after exercise in CA subjects but not in AA subjects (P < 0.05). Women exhibited greater reductions in AIx after maximal aerobic exercise compared with men (P < 0.05). In conclusion, race and sex impact vascular and central hemodynamic responses to exercise. Young AA and CA subjects exhibited differential responses in central stiffness and central BP after acute maximal exercise. Premenopausal women had greater augmented pressure at rest and after maximal aerobic exercise than men. Future research is needed to examine the potential mechanisms.