Radial, carotid and aortic distensibility in congestive heart failure: effects of high-dose angiotensin-converting enzyme inhibitor or low-dose association with angiotensin type 1 receptor blockade

Endothelial, Vascular and Sympathetic Alterations as Therapeutic Targets in Chronic Heart Failure

Vascular and sympathetic abnormalities characterize chronic heart failure (CHF). Alterations include (1) a reduction in arterial distensibility, (2) endothelial dysfunction, (3) a decrease in arterial compliance and a parallel increase in arterial stiffness, and (4) sympathetic cardiovascular activation. Altogether, these alterations represent important targets in therapeutic interventions, because they display an independent negative impact on the disease prognosis, favouring disease progression and the development of cardiovascular complications with direct and indirect mechanisms. The present review will examine the effects of the different therapeutic interventions targeting the vascular/sympathetic alterations detected in CHF. Non-pharmacological, pharmacological and device-based treatments will be discussed in detail, highlighting the possible mechanisms responsible for the vascular/sympathetic effects of each intervention. Finally, the unmet goals in treatment in relation to endothelial and adrenergic targets will be also discussed.

Radial artery diameter: a comprehensive systematic review of anatomy

AIMS

The objective of this systematic review is to determine with the highest accuracy the average radial artery (RA) diameter overall and in certain subgroups. The aim of this study is to provide assistance in the development of fitting transradial devices, an increasingly popular intervention.

METHODS

Several databases were used to extract appropriate studies highlighting RA diameter. Databases used in the generation of this study were Ovid EBM Reviews, Ovid Embase, Ovid Medline, Scopus and Web of Science Core Collection. RA diameter was determined overall, in males versus females, adults only, adults+children, in the presence of comorbidities, and finally RA diameter in the context of various vasodilators.

RESULTS

A total of 71 studies were included. The average RA diameter overall was determined to be 2.62±0.15 mm in children+adults and 2.70±0.15 mm in adults only. In comparison to an RA diameter of 2.68±0.24 mm in adult males, the diameter was found to be 2.27±0.27 mm in adult females (p=0.028). As for comorbidities, the mean RA diameter in adult patients with hypertension and congestive heart failure was 2.72±0.37 mm and 2.80±0.25 mm, respectively. Finally, the mean RA diameter with nitrate and angiotensin-converting enzyme (ACE) inhibitor use was 2.97±0.53 mm and 2.82±0.29 mm respectively. For comparison, the average outer diameter of a 5 French introducer sheath is 2.29 mm and a 6 French introducer sheath is 2.62 mm.

CONCLUSIONS

The findings presented in this study will help determine the most appropriate transradial device to use in several different populations in the context of vasodilator usage or the absence thereof.

Neurohormones, inflammatory mediators, and cardiovascular injury in the setting of heart failure

Neurohormones and inflammatory mediators have effects in both the heart and the peripheral vasculature. In patients with heart failure (HF), neurohormonal activation and increased levels of inflammatory mediators promote ventricular remodeling and development of HF, as well as vascular dysfunction and arterial stiffness. These processes may lead to a vicious cycle, whereby arterial stiffness perpetuates further ventricular remodeling leading to exacerbation of symptoms. Although significant advances have been made in the treatment of HF, currently available treatment strategies slow, but do not halt, this cycle. The current treatment for HF patients involves the inhibition of neurohormonal activation, which can reduce morbidity and mortality related to this condition. Beyond benefits associated with neurohormonal blockade, other strategies have focused on inhibition of inflammatory pathways implicated in the pathogenesis of HF. Unfortunately, attempts to target inflammation have not yet been successful to improve prognosis of HF. Further work is required to interrupt key maladaptive mechanisms involved in disease progression.

New indices of arterial stiffness correlate with disease severity and mid-term prognosis in acute decompensated heart failure

Arterial stiffness has been implicated in pathophysiology of heart failure (HF) since it is involved in the ventricular-vascular coupling. Recently, new indices obtained by a cuff oscillometric technique, the arterial velocity pulse index (AVI) for the stiffness of central arteries and the arterial pressure volume index (API) for the stiffness of peripheral arteries have been developed and validated. However, the AVI and API measurement has not been attempted in HF population. This study aimed to investigate the relationship between the AVI, API and clinical parameters and outcomes in HF patients. A prospective cohort of patients with acute decompensated HF were enrolled within 6 months, who were admitted to a tertiary referral hospital in China. Measurement of the AVI and API (AVE-1500, Shisei Datum, Tokyo, Japan) was performed on the day of admission and discharge. Patients were followed up to 6 months for the composite endpoint of all-cause death and rehospitalization for HF. A total of 127 patients were recruited for analysis (60 ± 15 years, 70% male). 80% of the patients were in New York Heart Association (NYHA) Class III or IV at admission with mean left ventricular ejection fraction (LVEF) of 34 ± 9%. During hospitalization, all patients received guideline-directed medical therapy if not contraindicated. The AVI (27.3 ± 5.0 vs. 28.6 ± 6.7, P = 0.002) and API (24.9 ± 4.9 vs. 26.0 ± 6.5, P = 0.05) were lower at discharge than at admission. By dividing the patients into mild to severe group based on systolic blood pressure (SBP) and LVEF or into tertiles according to the amino-terminal pro-brain natriuretic peptide (NT-proBNP), transmitral E velocity over mitral annular e' velocity (E/e' ratio), it was observed that the AVI increased with a higher level of NT-proBNP (P for trend < 0.001), a larger E/e' (P for trend < 0.001) and a lower LVEF (P for trend = 0.0183), while the API increased as the E/e' and systolic blood pressure became higher (both P for trend < 0.05). The improvement in AVI at discharge was correlated with LVEF (R = - 0.3024, P < 0.05) and NT-proBNP improvement (R = 0.3118, P < 0.05), while the change in API was positively correlated with SBP change (R = 0.3897, P < 0.001). In 6 months after discharge, there were 52 predefined events including 15 deaths and 44 rehospitalization for HF. Apart from the level of NT-proBNP, the AVI at discharge of ≥ 26 showed a trend of being associated with the composite outcome (HR 2.747, 95% CI 1.411-5.349, P < 0.001 for univariate analysis; HR 1.864, 95% CI 0.892-3.893, P = 0.09761 for multivariate analysis). New noninvasive arterial stiffness indices as the AVI and API reflected severity of illness and midterm prognosis in admitted HF patients. Further studies are warranted for understanding its mechanisms and developing clinical applications.

Resting and exercise arterial dysfunction in anthracycline-treated adult survivors of childhood cancers

BACKGROUND

Emerging evidence suggests potential arterial damage with the use of anthracycline-based chemotherapeutic regimens. We determined arterial function at rest and during exercise in anthracycline-treated adult survivors of childhood cancers.

METHODS

Ninety-six adult survivors (54 males) aged 25.0 ± 5.9 years and 60 (30 males) healthy controls were studied. Central systolic blood pressure (cSBP) and radial augmentation index (rAI) was determined by applanation tonometry. Carotid arterial stiffness and intima-media thickness (IMT) were assessed using high-resolution ultrasound.

RESULTS

At rest, survivors had significantly greater carotid IMT (p < 0.001) and stiffness index (p < 0.001), and higher cSBP (p = 0.037), rAI (p = 0.004) and rAI adjusted for a heart rate of 75/min (p = 0.009) than controls. At submaximal supine exercise testing, survivors had significantly greater percentage increase in carotid stiffness than controls (p < 0.001). Among survivors, 32 and 53% had respectively carotid IMT and exercise stiffness index exceeding normal (> + 2SD of controls). The slopes of increase in carotid IMT (p < 0.001) and exercise-induced changes in carotid stiffness (p < 0.001) with age were significantly greater in survivors than controls. Multivariate analysis revealed carotid IMT (β = 0.32, p < 0.001) to be an significant correlate of dynamic percentage increase in stiffness index during exercise.

CONCLUSIONS

Arterial dysfunction is evident at rest and worsens during exercise in anthracycline-treated adult survivors of childhood cancers.

Strain of ascending aorta on cardiac magnetic resonance in 1027 patients: Relation with age, gender, and cardiovascular disease

OBJECTIVES

To evaluate ascending aortic strain (AAS) with cardiac magnetic resonance (CMR) in a large consecutive series of patients with different types of cardiovascular disease (CVD).

METHODS

Two-dimensional phase-contrast gradient-echo sequences of the ascending aorta were retrospectively reviewed in 1027 patients (726 males, 301 females). Aortic lumen area was segmented using a semi-automatic approach to calculate AAS values. Subgroup analysis was performed for patients with normal CMR, tetralogy of Fallot (ToF), and ischemic heart disease (IHD). Multivariate and post-hoc analyses were performed to evaluate the effect of age, gender, and CVD on AAS values. Shapiro-Wilk, three- and two-way ANOVA, Mann-Whitney U, and Spearman correlation statistics were used.

RESULTS

Multivariate analysis showed significant differences in AAS among decades of age (p<0.001), genders (p=0.006) and CVD subgroups (p<0.001) without interaction among these factors. A gender-related difference (higher AAS in females) was significant in ToF (p=0.008), while an AAS reduction during aging was observed in all CVD subgroups. Post-hoc analysis showed a significantly lower AAS in ToF and IHD patients compared to subjects with normal CMR (p<0.001).

CONCLUSION

Differences in age, gender, and CVD independently affect AAS. The lower AAS observed in ToF fosters its assessment during follow-up in adulthood. Future studies on causes and clinical implications of a higher AAS in females affected by ToF are warranted.

Fully automated contour detection of the ascending aorta in cardiac 2D phase-contrast MRI

PURPOSE

In this study we proposed a fully automated method for localizing and segmenting the ascending aortic lumen with phase-contrast magnetic resonance imaging (PC-MRI).

MATERIAL AND METHODS

Twenty-five phase-contrast series were randomly selected out of a large population dataset of patients whose cardiac MRI examination, performed from September 2008 to October 2013, was unremarkable. The local Ethical Committee approved this retrospective study. The ascending aorta was automatically identified on each phase of the cardiac cycle using a priori knowledge of aortic geometry. The frame that maximized the area, eccentricity, and solidity parameters was chosen for unsupervised initialization. Aortic segmentation was performed on each frame using active contouring without edges techniques. The entire algorithm was developed using Matlab R2016b. To validate the proposed method, the manual segmentation performed by a highly experienced operator was used. Dice similarity coefficient, Bland-Altman analysis, and Pearson's correlation coefficient were used as performance metrics.

RESULTS

Comparing automated and manual segmentation of the aortic lumen on 714 images, Bland-Altman analysis showed a bias of -6.68mm², a coefficient of repeatability of 91.22mm², a mean area measurement of 581.40mm², and a reproducibility of 85%. Automated and manual segmentation were highly correlated (R=0.98). The Dice similarity coefficient versus the manual reference standard was 94.6±2.1% (mean±standard deviation).

CONCLUSION

A fully automated and robust method for identification and segmentation of ascending aorta on PC-MRI was developed. Its application on patients with a variety of pathologic conditions is advisable.

Effects of chronic carotid baroreceptor activation on arterial stiffness in severe heart failure

BACKGROUND

Heart failure with reduced ejection fraction (HFrEF) is characterized by activation of the sympathetic nervous system and increased arterial stiffness, leading to an impaired ventricular-vascular coupling. Baroreflex activation therapy (BAT) has been shown to reduce muscle sympathetic nerve activity (MSNA) and improve clinical status of patients with HFrEF. The purpose of this investigation was to determine the effects of BAT on arterial stiffness in HFrEF.

METHODS AND RESULTS

MSNA, clinical variables, and parameters of central blood pressure (BP) and arterial stiffness were collected in 18 NYHA Class III HFrEF patients, nine receiving BAT and nine continuing with optimal medical management alone. Patients were followed for 3 months, with measurements at that time compared to baseline evaluation. Baseline characteristics of the groups were well matched. At 3 months, BAT did not improve central BP and arterial stiffness despite a significant amelioration of MSNA, NYHA class, Minnesota living with heart failure questionnaire score, number of heart failure medications and six-minute walking distance. The control group exhibited no significant changes in all the measured variables.

CONCLUSIONS

Despite significant reductions in MSNA and clinical improvement, BAT does not appear to chronically modify arterial stiffness within this HFrEF cohort. Additional study is required to determine if this result applies to the HFrEF population as a whole.

Relation of Central Arterial Stiffness to Incident Heart Failure in the Community

BACKGROUND

Arterial stiffness, pressure pulsatility, and wave reflection are associated with cardiovascular disease. Left ventricular function is coupled to proximal aortic properties, but the association of central aortic stiffness and hemodynamics with incident clinical heart failure (HF) is not well described.

METHODS AND RESULTS

Framingham Study participants without clinical HF (n=2539, mean age 64 years, 56% women) underwent applanation tonometry to measure carotid-femoral pulse wave velocity (CFPWV), central pulse pressure, forward wave amplitude, and augmentation index. CFPWV was inverse-transformed to reduce heteroscedasticity and multiplied by -1 to restore effect direction (iCFPWV). Over 10.1 (range 0.04-12.9) years, 170 HF events developed. In multivariable-adjusted analyses, iCFPWV was associated with incident HF in a continuous, graded fashion (hazards ratio [HR] per SD unit [SDU] 1.29, 95% confidence interval [CI] 1.02-1.64, P=0.037). iCFPWV was associated with HF with reduced ejection fraction (HR=1.69/SDU, 95% CI 1.19-2.42, P=0.0037) in age- and sex-adjusted models, which was attenuated in multivariable-adjusted models (P=0.065). Central pulse pressure and forward wave amplitude were associated with HF in age- and sex-adjusted models (per SDU, HR=1.20, 95% CI 1.06-1.37, P=0.006, and HR=1.15, 95% CI 1.01-1.31, P=0.036, respectively), but not in multivariable-adjusted models (both P≥0.28). Augmentation index was not associated with HF risk (P≥0.19 in all models).

CONCLUSIONS

In our prospective investigation of a large community-based sample of middle-aged to elderly individuals, greater aortic stiffness (reflected by higher iCFPWV) was associated with increased risk of HF. Future studies may investigate the impact of modifying aortic stiffness in reducing the community burden of HF.

Reproducibility of functional aortic analysis using magnetic resonance imaging: the MESA

AIMS

To assess the test-retest, intra- and inter-reader reliability of thoracic aorta measurements by magnetic resonance imaging (MRI).

METHODS AND RESULTS

Twenty-five participants underwent aortic MRI twice over 13 ± 7 days. All aortic variables from baseline and repeat MR were analysed using a semi-automated method by the ARTFUN software. To assess the inter-study reproducibility of aortic variables, we calculated intraclass correlation coefficient (ICC) for individual aortic measurements. Intra- and inter-observer variability was also assessed using the baseline MR data. Mean ascending aortic strain had moderate inter-study reproducibility (11.53 ± 6.44 vs. 10.55 ± 6.64, P = 0.443, ICC = 0.53, P < 0.01). Mean descending aortic strain and arch pulse wave velocity (PWV) had good inter-study reproducibility (descending aortic strain: 8.65 ± 5.30 vs. 8.35 ± 5.26, P = 0.706, ICC = 0.74, P < 0.001; PWV: 9.92 ± 4.18 vs. 9.94 ± 4.55, P = 0.968, ICC = 0.77, P < 0.001, respectively). All aortic variables had excellent intra- and inter-observer reproducibility (intra-: ICC range, 0.87-0.99, inter-: ICC range, 0.56-0.99, respectively).

CONCLUSION

Inter-study reproducibility of all aortic variables was acceptable. Intra- and inter-observer reproducibility of all aortic variables was excellent. MRI can provide a repeatable method of measuring aortic structural and functional parameters.

Structural and Functional Abnormalities of Carotid Artery and Their Relation with EVA Phenomenon

Early vascular aging is a process characterized by a reduction in arterial elastin with an increase in collagen that has been related to cardiovascular risk factor and can determine an increased arterial stiffness and central blood pressure. It can be measured by several non invasive methods and in different arterial segment. The present paper will focus on functional (local stiffness parameter) and structural (intima media thickness) carotid arteries alterations typically evaluated by ultrasound methods. Methodological, research and clinical issue has been reviewed.

Evolution of aortic wall thickness and stiffness with atherosclerosis: long-term follow up from the multi-ethnic study of atherosclerosis

The study was performed to determine age, sex, and time-dependent changes in aortic wall thickness (AWT) and to evaluate cross-sectional associations between AWT and arterial stiffness in older adults. Three hundred seventy-one longitudinal and 426 cross-sectional measurements of AWT from cardiovascular magnetic resonance imaging studies conducted within the Multi-Ethnic Study of Atherosclerosis were analyzed at 2 points in time, in 2000 to 2002 and then again from follow-up examinations in 2010 to 2012. Aortic wall thickness was determined from a double inversion recovery black-blood fast spin-echo sequence, and aortic stiffness was measured from a phase-contrast cine gradient echo sequence. The thickness of the midthoracic descending aortic wall was measured and correlated to distensibility of the ascending aorta and aortic pulse wave velocity. The average rate of AWT change was 0.032 mm/y. The increase in AWT was greater for those aged 45 to 54 years relative to individuals older than 55 years (P trend<0.001). Ascending aortic distensibility was lower (P<0.001) and pulse wave velocity was higher (P=0.012) for hypertensive subjects. After adjustment for traditional risk factors, distensibility of the ascending aorta was significantly related to AWT in participants without hypertension. Hypertension was associated with increased aortic stiffness independent of aortic wall thickness.

Arterial wave reflections and ventricular-vascular interaction in patients with left ventricular systolic dysfunction

Central aortic pressure waveform (AoPW) is the summation of a forward-traveling wave generated by the left ventricle and a backward-traveling wave caused by the reflection of the forward wave. The aim of this study was to evaluate the effect of ventricular-vascular coupling on the morphology of AoPW in chronic heart failure patients with different degrees of left ventricular systolic dysfunction (LVSD) using pulse wave analysis (PWA). PWA of AoPW and left ventricular (LV) function were evaluated by applanation tonometry in 26 control subjects, in 12 patients with left ventricular ejection fraction (LVEF) ≤ 30%, and in 14 patients with LVEF > 30%. Augmentation pressure, augmentation index, wasted energy, and ejection duration were lower in patients with LVEF ≤ 30% than in those with LVEF > 30% and in control subjects. Furthermore, augmentation index showed an inverse correlation with Doppler mitral E-wave amplitude (r = -0.40; P = 0.04) and E/A ratio (r = -0.42; P = 0.03) and a direct correlation with deceleration time of mitral E-waves (r = 0.39; P = 0.04). In patients with severe LVSD (LVEF ≤ 30%), aortic wave reflections negatively interfere with LV function and induce a shortening of ejection duration. In contrast, AoPW is similar in patients with moderate LVSD (LVEF > 30%) and in control subjects.

Correlation between Proximal Abdominal Aortic Stiffness Measured by Ultrasound and Brachial-Ankle Pulse Wave Velocity

Background and Objectives

The proximal portion of the abdominal aorta (AA) is characterized by minimal arteriosclerosis compared with other aortic segments. To assess the clinical usefulness of this characteristic, the correlation between ultrasonographically measured proximal AA stiffness and brachial-ankle pulse wave velocity (baPWV) was examined.

Subjects and Methods

285 subjects were analyzed, half with hypertension and half with normal blood pressure. Proximal AA was examined using ultrasonography; strain, distensibility, elastic modulus, and the stiffness index were determined. After adjustment for age, gender, body mass index (BMI), systolic blood pressure (SBP), and heart rate, the relationships between baPWV and all these parameters were tested.

Results

The mean age of the study subjects was 58.1±12.8 years and the mean BMI was 24.3±3.8 kg/cm². 58.9% of the subjects were female. 42.8% were hypertensive subjects. Among the hypertensive subjects, 56.0% were taking antihypertensive medication. Adjusted partial correlation coefficients for the relationship between baPWV with strain, distensibility, elastic modulus, and the stiffness index of the proximal AA were -0.203 (p=0.01), -0.121 (p=0.129), 0.304 (p=0.0001), and 0.299 (p=0.0001), respectively, in normotensive subjects. In the multivariate analyses, such correlations were observed mainly in the normotensive group, whereas there was no association among hypertensive subjects regardless of antihypertensive medication status.

Conclusion

baPWV is moderately correlated with the stiffness parameters for the proximal AA, mainly in normotensive subjects.

Elastic properties of peripheral arteries in heart failure patients in comparison with normal subjects

Understanding the change in elastic properties of peripheral arteries in heart failure patients is of particular importance, especially when compared with normal subjects. To investigate factors associated with their difference, 40 normal subjects and 60 heart failure patients were studied. Electrocardiograms, carotid pulses and radial pulses were simultaneously recorded to determine carotid-radial pulse transit time (carotid-radial PTT), arm pulse wave velocity (PWV), and arterial volume distensibility. In comparison with normal subjects, carotid-radial PTT was lower by 8 ms in heart failure patients, arm PWV higher by 1.4 m/s, and peripheral arterial distensibility lower by 0.04 % per mmHg (all significant, P < 0.01). Peripheral arterial distensibility was significantly related to systolic blood pressure (SBP) and to left ventricular ejection fraction (LVEF) for heart failure patients (both P < 0.001), but the relationship for the normal group was not statistically significant (both 0.05 < P<0.1). Ageing had a significant inverse relationship with arterial distensibility in normal subjects (P < 0.05), but not in heart failure patients (P = 0.59). No subject in the normal group had an arterial distensibility lower than 0.1 % per mmHg, in comparison with 28 % (17/60) in the heart failure group. Peripheral arterial distensibility has been shown to be significantly lower in heart failure patients in comparison with normal subjects. High SBP and low LVEF were the main factors associated with low arterial distensibility in heart failure patients.

Carotid arterial stiffness and its relationship to exercise intolerance in older patients with heart failure and preserved ejection fraction

Heart failure with a preserved ejection fraction (HFpEF) is the dominant form of heart failure in the older population. The primary chronic symptom in HFpEF is severe exercise intolerance; however, its pathophysiology and therapy are not well understood. We tested the hypothesis that older patients with HFpEF have increased arterial stiffness beyond what occurs with normal aging and that this contributes to their severe exercise intolerance. Sixty-nine patients ≥60 years of age with HFpEF and 62 healthy volunteers (24 young healthy subjects ≤30 years and 38 older healthy subjects ≥60 years old) were examined. Carotid arterial stiffness was assessed using high-resolution ultrasound, and peak exercise oxygen consumption was measured using expired gas analysis. Peak exercise oxygen consumption was severely reduced in the HFpEF patients compared with older healthy subjects (14.1±2.9 versus 19.7±3.7 mL/kg per minute; P<0.001) and in both was reduced compared with young healthy subjects (32.0±7.2 mL/kg per minute; both P<0.001). In HFpEF compared with older healthy subjects, carotid arterial distensibility was reduced (0.97±0.45 versus 1.33±0.55×10(-3) mm Hg(-1); P=0.008) and Young's elastic modulus was increased (1320±884 versus 925±530 kPa; P<0.02). Carotid arterial distensibility was directly (0.28; P=0.02) and Young's elastic modulus was inversely (-0.32; P=0.01) related to peak exercise oxygen consumption. Carotid arterial distensibility is decreased in HFpEF beyond the changes attributed to normal aging and is related to peak exercise oxygen consumption. This supports the hypothesis that increased arterial stiffness contributes to exercise intolerance in HFpEF and is a potential therapeutic target.

Increasing plasma free fatty acids in healthy subjects induces aortic distensibility changes seen in obesity

BACKGROUND

Elevated free fatty acid (FFA) levels are known to impair aortic elastic function. In obesity, FFA levels are elevated and aortic distensibility (AD) reduced in a pattern that predominantly affects the distal aorta. Despite this, the role of FFAs in obesity-related aortic stiffness remains unclear.

METHODS AND RESULTS

Using vascular MRI, we aimed to determine if (1) FFA level correlated with AD in obesity; and (2) whether elevating FFA acutely and subacutely in normal-weight subjects reproduced the distal pattern of AD change in obesity. To do this, regional AD was recorded in 35 normal-weight and 70 obese subjects and then correlated with FFA levels. When compared with normal weight, obesity was associated with reduced AD in a pattern predominantly affecting the distal aorta (ascending aorta by -22%, proximal descending aorta by -25%, and abdominal aorta by -35%; P<0.001). After controlling for age, blood pressure, and body mass index, FFA levels remained negatively correlated with abdominal AD (r=-0.43, P<0.01). In 2 further normal-weight groups, AD was recorded before and after elevation of FFA levels with intralipid infusion (by +535%, n=9) and a 5-day high-fat, low-carbohydrate diet (by +48%, n=14).

CONCLUSIONS

Both intralipid infusion and a low-carbohydrate diet resulted in reduced abdominal AD (infusion -22%, diet -28%; both P<0.05), reproducing the distal pattern AD reduction seen in obesity. These findings suggest that elevated FFA impair AD in obesity and provide a potential therapeutic target to improve aortic elastic function in obesity.

Comparison of echotracking and magnetic resonance assessment of abdominal aorta distensibility and relationships with pulse wave velocity

Arterial distensibility can be measured either by echotracking or by nuclear magnetic resonance (MRI). Little information, however, is available on the comparison between the two methods and on the relationships between the results obtained with the two approaches and the arterial stiffness gold standard measurement, i.e., pulse wave velocity (PWV). In 28 normotensive subjects (age 33.0 ± 10.4 years, mean ± SD) we measured aortic diameter 1 cm above iliac bifurcation, aortic pulse pressure by tonometry and calculated arterial distensibility via the Reneman formulae for both methods. Aortic diameter and aortic distensibility were not superimposable and higher values were systematically detected with the MRI approach than with the ultrasound one. However, PWV showed a significant correlation with aortic distensibility values obtained by both methods (r = 0.50 and r = 0.49, p < 0.05). These data provide evidence that MRI-measured distensibility value is higher than that obtained via echotracking. The significant correlation with PWV, however, suggests that both methods can be regarded as valuable approaches. Considering the greater economic cost and the lower availability in daily clinical and research practice of MRI, echotracking ultrasonography can be regarded as a reliable and feasible method to assess aortic distensibility.

The effect of dobutamine without and with L-arginine on arterial compliance in heart failure patients

The effect of dobutamine on carotid and brachial arteries compliance and the association of L-arginine as a potential nitric oxide pathway restorer were evaluated in patients with heart failure. Twenty-seven outpatients participated. Drugs used for the treatment of heart failure were withheld at least 24 hours before the study. The carotid and brachial artery diameters and hemodynamic variables were evaluated by ultrasonography and Doppler in baseline conditions, with dobutamine, with flow-mediated dilatation (FMD), and with placebo or L-arginine alone and associated with dobutamine. There was a significant increase in carotid peak blood flow with dobutamine when compared with that at baseline (P = 0.0001) or with L-arginine or placebo (P = 0.0001 and P = 0.0001, respectively), with increase of the cardiac index (P = 0.0001). Dobutamine did not increase carotid arterial compliance. FMD significantly increased the brachial peak blood flow (P = 0.0022) and the artery diameter (P = 0.0001). Dobutamine did not change the brachial artery diameter. Brachial peak blood flow was increased with dobutamine alone or associated with placebo or L-arginine comparing with L-arginine or placebo alone (P = 0.0168 and P = 0.0140, respectively), but was not increased compared with that at baseline. L-arginine infusion was not associated with changes in carotid, brachial, or in the cardiac index. We concluded that dobutamine increased carotid peak blood flow in patients with heart failure, although without changing the arterial compliance. The FMD of brachial artery was maintained, while brachial artery response to dobutamine infusion was less reliable. The carotid artery may be under the direct influence of the heart, while the brachial artery may be under predominant local control.

Reduced ascending aortic strain and distensibility: earliest manifestations of vascular aging in humans

Arterial stiffness predicts cardiovascular events beyond traditional risk factors. However, the relationship with aging of novel noninvasive measures of aortic function by MRI and their interrelationship with established markers of vascular stiffness remain unclear and currently limit their potential impact. Our aim was to compare age-related changes of central measures of aortic function with carotid distensibility, global carotid-femoral pulse wave velocity, and wave reflections. We determined aortic strain, distensibility, and aortic arch pulse wave velocity by MRI, carotid distensibility by ultrasound, and carotid-femoral pulse wave velocity by tonometry in 111 asymptomatic subjects (54 men, age range: 20 to 84 years). Central pressures were used to calculate aortic distensibility. Peripheral and central pulse pressure, augmentation index, and carotid-femoral pulse wave velocity increased with age, but aortic strain and aortic arch PWV were most closely and specifically related to aging. Ascending aortic (AA) strain and distensibility decreased, respectively, by 5.3+/-0.5% (R(2)=0.54, P<0.0001) and 13.6+/-1 kPa(-1)x10(-3) (R(2)=0.62, P<0.0001), and aortic arch pulse wave velocity increased by 1.6+/-0.13 m/sec (R(2)=0.60, P<0.0001) for each decade of age after adjustment for gender, body size, and heart rate. We demonstrate in this study a dramatic decrease in AA distensibility before the fifth decade of life in individuals with diverse prevalence of risk factors free of overt cardiovascular disease. In particular, compared with other measures of aortic function, the best markers of subclinical large artery stiffening, were AA distensibility in younger and aortic arch pulse wave velocity in older individuals.

Pulse wave analysis of the aortic pressure waveform in severe left ventricular systolic dysfunction

BACKGROUND

The effect of moderate left ventricular systolic dysfunction (LVSD) on ventricular/vascular coupling and the aortic pressure waveform (AoPW) has been well described, but the effect of severe LVSD has not.

METHODS AND RESULTS

We used noninvasive, high-fidelity tonometry of the radial artery and a mathematical transfer function to generate the AoPW in 25 treated patients with LVSD (mean LV ejection fraction, 24+/-8.8%; range, 11% to 40%; 21 patients <30%). Pulse wave analysis of the AoPW was used to characterize ventricular/vascular coupling and compared with pulse wave analysis performed in 25 normal subjects matched for age, gender, height, body mass index, and heart rate. Measurements obtained using pulse wave analysis in LVSD patients indicated features of poor LV stroke performance and also reduced indices of arterial stiffness: increased travel time of the pressure wave (147+/-10 ms versus 132+/-21 ms; P<0.001); decreased systolic duration of reflected wave (134+/-24 ms versus 167+/-26 ms; P<0.001); ejection duration (277+/-22 ms versus 299+/-25 ms; P<0.008); percent systolic duration (32+/-5.3% versus 35+/-4.0%; P<0.02); aortic systolic pressure (100+/-16 mm Hg versus 121+/-16 mm Hg; P<0.001); unaugmented pressure (24+/-6.3 mm Hg versus 32+/-6.4 mm Hg; P<0.001); augmented pressure (4.8+/-3.1 mm Hg versus 9.6+/-4.5 mm Hg; P<0.001); pulse pressure (28+/-7.4 mm Hg versus 42+/-9.5 mm Hg; P<0.001); augmentation index (12+/-6.6% versus 23+/-7.6%; P<0.006); wasted LV effort (5.3+/-2.8x10(2) dyne sec/cm(2) versus 17+/-10x10(2) dyne sec/cm(2); P<0.001); systolic pressure time index (17+/-4.1x10(2) mm Hg-sec/min versus 23+/-4.2x10(2) mm Hg sec/min; P<0.001); and pressure systolic area (383+/-121 mm Hg sec/min versus 666+/-150 mm Hg sec/min; P<0.001).

CONCLUSIONS

Severe LVSD causes measurable changes in the AoPW. Standardization of AoPW findings in LVSD patients may allow for the clinical use of radial artery pulse wave analysis to noninvasively determine the severity of dysfunction and aid in logical therapy.

Cardiac resynchronization results in aortic blood flow-associated changes in the arterial load components: basal biomechanical conditions determine the load changes

The cardiac resynchronization therapy (CRT)effects on the arterial load components, the mechanisms (i.e.haemodynamic changes-dependence) involved in the load reduction and the factors (i.e. basal load conditions) associated with the load changes after CRT, are to be evaluated.

AIMS

a)to analyze the potential changes in the arterial load components(peripheral resistances, arterial compliance and impedance)associated with the CRT, b) to determine if the load components changes are associated with variations in haemodynamic variables (pressure, heart rate or blood flow), c) to analyze the relationship between the load components basal state and their changes after CRT. To fulfill these aims cardiac and arterial structural and mechanical parameters were non-invasively evaluated in 8 heart failure patients, pre- and post-CRT (23+/-8 days). The main results were that short-term after CRT: 1)there were changes in the static and dynamic determinants of the arterial load; 2) the changes in the load components were not associated with heart rate or pressure variations, but with blood flow changes, and 3) the load components basal levels and their changes after CRT were associated.

Effect of Angiotensin‐Converting Enzyme Inhibitors on Arterial Stiffness in Hypertension: Systematic Review and Meta‐Analysis

Arterial stiffness is an independent cardiovascular prognostic factor and is modulated by angiotensin-converting enzyme inhibitors (ACEIs). The authors performed a meta-analysis of clinical trials investigating the effects of ACEIs on pulse wave velocity (PWV) or augmentation index. The search included randomized clinical trials as well as uncontrolled studies that measured in-treatment changes in arterial stiffness. The authors performed separate analyses for carotid-femoral PWV, brachioradial PWV, and augmentation index. Average absolute and relative reduction in mean arterial pressure and PWV were -15.4 mm Hg and -13.04% and -1.15 m/s and -9.74% for carotid-femoral PWV studies; and -11.2 mm Hg and -9.3% and -1.9 m/s and -16.7% for brachioradial PWV studies. There was a greater reduction in augmentation index by ACEIs when compared with controls (-1.0% to -5.3%). The authors conclude that ACEIs have modest beneficial effects on arterial stiffness measured as PWV and augmentation index, and this effect is at least partly independent of changes in blood pressure.

Relationship between impaired elastic properties of aorta with left ventricle geometric patterns and left ventricle diastolic functions in patients with newly diagnosed essential hypertension

The aim of this study was to investigate the association between elastic properties of aorta with left ventricle (LV) geometric patterns and LV diastolic functions in patients with newly diagnosed hypertension (HT). We studied 149 patients with newly diagnosed HT and 29 healthy control subjects. Echocardiographic examination was performed to all subjects. Ascending aorta (Ao) diameters (mm/m2) and Ao elastic indexes - namely, Ao strain [AS] (%), Ao distensibility [AD] (cm2 dyn(-1) x 10(-6)) were calculated. Four different geometric patterns were identified in hypertensive patients according to LV mass index (LVMI) and relative wall thickness (RWT). Tissue Doppler-derived Ea/Aa was determined from the all subjects. Patients vs. control subjects had lower mean AS and AD (p < 0.001 for both). Mean AS and AD of all geometric patterns significantly decreased compared with control group (p < 0.05 for all). Both AS and aortic AD of concentric remodelling (CR; p = 0.017 for both) and concentric hypertophic groups (p < 0.001 for both) were decreased compared with normal LV group. AS and AD of concentric hypertrophic pattern was lower than that of the CR group (p = 0.011 and 0.020 respectively) and the eccentric hypertrophic group (p < 0.001 and p = 0.002, respectively). Both AS and AD of the CR group were similar to that of the eccentric hypertrophic group (p > 0.05 for both). Both AS and AD were significantly correlated with age (beta = -0.178, p = 0.025, beta = -0.158, p = 0.029 respectively), LVMI (beta = -0.223, p = 0.022, beta = -263, p = 0.003 respectively), RWT (beta = -0.196, p = 0.019, beta = -0.189, p = 0.013 respectively) and Ea/Aa (beta = 0.174, p = 0.045, beta = 0.247, p = 0.002 respectively) in multiple linear regression analysis. Elastic properties of aorta were impaired in newly diagnosed HT. The degree of this impairment is different among various LV geometric patterns. In addition, impaired elastic properties of aorta were associated with RWT, LVMI and diastolic disfunctions, besides age, but not with LV geometry.

Elastic properties of the reconstructed aorta in hypoplastic left heart syndrome

BACKGROUND

Patients with repaired coarctation of the aorta retain abnormal elastic properties of the aorta. It is not known whether patients with hypoplastic left heart syndrome also manifest abnormal elastic properties after palliative surgery. The presence of such abnormalities may have important clinical implications as reduced aortic compliance might adversely impact single right ventricular function.

METHODS

We prospectively evaluated the elastic properties of the aorta in a cohort of patients with hypoplastic left heart syndrome who had undergone the Norwood procedure with aortic arch reconstruction and subsequent bidirectional Glenn or Fontan procedure. The hypoplastic left heart syndrome patients (n = 20) were compared with single-ventricle patients (n = 18) without history of arch reconstruction and patients with double-ventricular lesions (n = 22). Aortic elastic function was quantified by distensibility index and stiffness index. M-mode measurements of the transverse aortic arch were obtained with transesophageal echocardiography under general anesthesia. Patients were evaluated at a median age of 22.2 months with no age difference between patient subgroups.

RESULTS

Distensibility index was significantly less (p = 0.007) and stiffness index greater (p = 0.005) in the reconstructed arch of hypoplastic left heart syndrome patients compared with single-ventricle and double-ventricle patients.

CONCLUSIONS

Patients with hypoplastic left heart syndrome after Norwood palliation have increased aortic stiffness and decreased distensibility in the reconstructed transverse arch. As previous studies in adults have shown that decreased aortic compliance increases the energy cost of cardiac ejection, examination of modifications to the surgical technique that might improve elastic properties is warranted.

Aortic stiffness correlates with an increased extracellular matrix turnover in patients with dilated cardiomyopathy

BACKGROUND

An increased extracellular matrix (ECM) turnover has been associated with poor survival in patients with chronic heart failure (CHF) due to dilated cardiomyopathy (DCM). However, the influence of the accelerated collagen turnover on the progressive large artery stiffening process characterizing CHF has not been clarified. This is relevant because aortic stiffening imposes an additional systolic load and impairs exercise tolerance in CHF patients. Therefore, we investigated whether the serum aminoterminal propeptide of type III collagen (PIIINP), an established marker of ECM turnover and tissue fibrosis in DCM, was associated with aortic stiffness in DCM patients.

METHODS AND RESULTS

A total of 89 patients with clinical diagnosis of DCM (age 62 +/- 9 years, 80% men, mean ejection fraction 34% +/- 8%) were selected. Aortic pulse-wave velocity (PWV), a well-established marker of aortic stiffness, was measured by Doppler ultrasonography. Serum concentration of PIIINP was determined by radioimmunoassay. Mean aortic PWV was 5.7 +/- 2.3 m/s, and PIIINP was 5.0 +/- 1.3 microg/L. The variables correlated with aortic PWV were age (r = 0.33, P = .002), PIIINP (r = 0.30, P = .005), heart rate (r = 0.27, P = .02), stroke volume (r = -0.24, P = .03) and New York Heart Association class (r = 0.25, P = .02). In a multivariate analysis, age (P = .02) and PIIINP (P = .01) were independently related with aortic PWV, accounting for 27% of its variance.

CONCLUSIONS

Higher serum PIIINP levels are independently associated with a stiffer aorta in DCM patients. This suggests that abnormalities in the ECM turnover might involve the proximal elastic vasculature and could partially explain the progressive large artery stiffening process characterizing CHF.

Aggressive antihypertensive strategies based on hydrochlorothiazide, candesartan or lisinopril decrease left ventricular mass and improve arterial compliance in patients with type II diabetes mellitus and hypertension

We investigated the effects of aggressive antihypertensive therapy based on hydrochlorothiazide, candesartan or lisinopril on left ventricular mass (LVM) index and arterial stiffness in hypertensive type II diabetic individuals. Seventy hypertensive type II diabetic individuals were treated with three antihypertensive strategies in a randomized, double-blind, double-dummy design. Blood pressure was titrated to levels below 130/85 mm Hg or a decrease in systolic pressure of 10% with a diastolic pressure below 85 mm Hg. After titration, patients were treated for 12 months. Mean blood pressures were 157/93, 151/94 and 149/93 mm Hg at baseline in the hydrochlorothiazide (n = 24), candesartan (n = 24) and lisinopril (n = 22) groups, and 135/80, 135/82 and 131/80 mm Hg after titration. About 70% reached target blood pressures, with the median use of three antihypertensive drugs. Left ventricular mass index and all estimates of arterial stiffness showed significant improvement after 12 months: that is, LVM index (-11 g/m(2); -8%); carotid distensibility coefficient (DC; +2.8 x 10(-3) kPa(-1); +27%), compliance coefficient (CC; +0.13 mm2/kPa; +21%) and elastic modulus (-0.19 kPa; -16%); femoral DC (+1.6 x 10(-3) kPa(-1); +50%) and CC (+0.08 mm2/kPa; +26%); brachial DC (+2.1 x 10(-3) kPa(-1); +39%) and CC (+0.03 mm2/kPa; +27%) and total systemic arterial compliance (+0.29 ml/mm Hg; +16%). No differences in outcome variables between treatment groups were observed. Aggressive antihypertensive treatment, although difficult to achieve, resulted in substantial reductions of LVM index and arterial stiffness in relatively uncomplicated hypertensive type II diabetic individuals. Strategies based on renin-angiotensin system inhibitors were not clearly superior to conventional (i.e. diuretic-based) strategies.

Assessment of aortic stiffness and ventricular diastolic functions in patients with Behçet’s disease

BACKGROUND

Behçet's disease is a systemic vasculitis in which studies have given conflicting results about ventricular diastolic functions. However, tissue Doppler echocardiography has never been used in any of these studies. Aortic stiffness, a cardiovascular risk factor, may also precede ventricular dysfunction.

OBJECTIVES

The aim of this study was to assess aortic stiffness and biventricular diastolic functions in patients with Behçet's disease.

METHODS

A total of 26 patients with Behçet's disease (mean age; 33+/-10 years) and 20 age- and sex-matched controls (mean age; 33+/-7 years) were included. Aortic stiffness was evaluated by aortic strain and distensibility. Ventricular diastolic functions were evaluated with both conventional and tissue Doppler echocardiography. Mitral E and A wave, E/A ratio of E wave, deceleration time, and isovolumic relaxation time were calculated.

RESULTS

There was no significant difference in diastolic Doppler parameters between patients and controls. Similarly, there was no significant difference in mitral annular E and A velocities between these two groups. Aortic strain in patients with Behçet's disease was found to be significantly less than in the controls (8.3+/-4.9% and 15.7+/-2.7% respectively, p<0.001). Aortic distensibility was also significantly low in patients with Behçet's disease when compared to controls (0.45+/-0.28 and 0.78+/-0.13 respectively, p<0.001). Beta index values were significantly high in Behçet's patients (7.23+/-5.93 and 2.69+/-0.55 respectively, p<0.001).

CONCLUSION

No significant diastolic dysfunction was found in left and right ventricles in patients with Behçet's disease by using both conventional and tissue Doppler echocardiography. However, an increase in aortic stiffness was found, suggesting an inflammatory involvement of proximal aorta.

Aortic elastic properties and left ventricular diastolic function in patients with Adamantiades-Behcet's disease

OBJECTIVES

We investigated whether Adamantiades-Behcet's disease (ABD) is related to impaired aortic (Ao) elastic properties and left ventricular (LV) function.

BACKGROUND

Adamantiades-Behcet's disease is an inflammatory disorder characterized by vasculitis leading to vascular complications and, rarely, myocarditis.

METHODS

We studied 82 patients with ABD (age: 40 +/- 12 years) and 24 normal control subjects by echocardiography. Abdominal Ao diameter (mm/m(2)) and Ao elastic indexes--namely, Ao strain (%), distensibility (cm(2) x dyn(-1)x 10(-6)), stiffness index, and pressure strain modulus (Ep) (cm(2) x dyn(-1) x 10(-6))--were calculated from the echocardiographically derived thoracic Ao diameters (mm/m(2)), and the measurement of pulse pressure obtained by cuff sphygmomanometry. Isovolumic relaxation time (IVRT) (ms), deceleration time (DT) (ms), and flow propagation velocity (FPV) (cm/s) were measured by Doppler echocardiography to assess diastolic LV function. The duration of disease and presence of vascular complications were noted.

RESULTS

Patients versus control subjects had increased Ao diameters (p < 0.01), lower mean Ao strain and distensibility (4 vs. 9 and 1.4 vs. 3.4, respectively, p < 0.01), higher mean aortic stiffness index and Ep (15.6 vs. 6 and 1.17 vs. 0.44, respectively, p < 0.01), and impaired IVRT and FPV (p < 0.01). Aortic function indexes were related to the duration of disease (p < 0.01) and increased DT (p < 0.01). Deceleration time >190 ms predicted vascular complications with 80% sensitivity and 71% specificity (odds ratio 6.52 [confidence interval: 2.23 to 19.03]).

CONCLUSION

Aortic elastic properties and diastolic LV function are impaired in patients with ABD and are interrelated. The link between diastolic LV dysfunction and vascular complications suggests the presence of a common pathophysiologic pathway and provides a possible marker of risk for vascular disease.

Noninvasive assessment of arterial stiffness and risk of atherosclerotic events

Investigation of arterial stiffness, especially of the large arteries, has gathered pace in recent years with the development of readily available noninvasive assessment techniques. These include the measurement of pulse wave velocity, the use of ultrasound to relate the change in diameter or area of an artery to distending pressure, and analysis of arterial waveforms obtained by applanation tonometry. Here, we describe each of these techniques and their limitations and discuss how the measured parameters relate to established cardiovascular risk factors and clinical outcome. We also consider which techniques might be most appropriate for wider clinical application. Finally, the effects of current and future cardiovascular drugs on arterial stiffness are also discussed, as is the relationship between arterial elasticity and endothelial function.