Mechanisms, pathophysiology, and therapy of arterial stiffness

Relation of haptoglobin phenotype to early vascular changes in patients with diabetes mellitus

Haptoglobin (Hp) is an antioxidant protein and the major susceptibility gene for atherosclerosis in diabetic patients. The effect of Hp phenotype on arterial compliance and metabolic and inflammatory parameters was investigated. Patients were divided into 3 groups according to Hp phenotype of Hp 2-2, Hp 2-1, and Hp 1-1. Arterial elasticity of large and small arteries was evaluated using the pulse-wave contour analysis method. The large-artery elasticity index (LAEI) was lower in patients with Hp 2-2 compared with Hp 1-1 (8.4 +/- 2.3 vs 12.6 +/- 4.1 ml/mm Hg x 100; p <0.0001). The difference in LAEIs between the Hp 2-1 and Hp 1-1 groups was also significant (9.9 +/- 2.6 vs 12.6 +/- 4.1 ml/mm Hg x 100; p = 0.025). The Hp 2-2 and Hp 2-1 groups did not differ from one another. The small-artery elasticity index (SAEI) was significantly lower in patients with Hp 2-2 compared with Hp 1-1 (2.8 +/- 1.0 vs 4.4 +/- 1.9 ml/mm Hg x 100; p = 0.004). Differences in SAEIs between patients with Hp 2-1 and Hp 1-1, as well as those with Hp 2-1 and Hp 2-2, were not detected. Systemic vascular resistance differed significantly across groups, driven by the difference between patients with Hp 2-2 and Hp 1-1. In conclusion, LAEI and SAEI were significantly lower and systemic vascular resistance was higher in homozygotes for the 2 allele (Hp 2-2) compared with patients with Hp 2-1 or Hp 1-1 phenotypes. Differences in arterial elasticity were detected despite the lack of by-phenotype differences in glycemic control, blood pressure, or presence of cardiovascular risk factors.

Changes of elastic properties of central arteries during acute static exercise and lower body negative pressure

The aim of this investigation was to determine the acute effects of isometric fatiguing handgrip (IFHG) and lower body negative pressure (LBNP) on indices of central arterial stiffness. Thirteen subjects were studied. Renal blood velocity (Duplex Ultrasound) and blood pressure (Finapres) were monitored during IFHG and LBNP at -30 and -50 mmHg. Radial pulse-wave forms were recorded by applanation tonometry. Central aortic waveforms and other hemodynamic parameters were assessed using the Sphygmocor software. Renal vascular resistance index (RVRI; mean BP/renal blood velocity) was used as index of sympathetic nervous system (SNS) engagement. RVRI increased during both IFHG and LBNP indicating that SNS was engaged; however, BP increased only during the IFHG. Pulse-wave analysis showed that during the IFHG protocol the transit time of the pulse wave decreased and the peripheral pulse pressure/nonaugmented central pulse pressure ratio increased from baseline. Both of these measurements suggest an increase in central large artery stiffness. During LBNP no changes in the indices of central stiffness were noted, in spite of a similar level of sympathetic system engagement. Heart rate increased during both protocols, whereas augmentation index increased during the IFHG protocol and decreased during the LBNP. Our major conclusion was that blood pressure rather than sympathetic activity seems to play the major role in modulating the elastic properties of the central arteries. The decrease in augmentation index during the LBNP protocol can be attributed to the increased heart rate, given that there is a negative correlation between these two parameters.

Rosuvastatin increases vascular endothelial PPARgamma expression and corrects blood pressure variability in obese dyslipidaemic mice

AIMS

Statins improve atherosclerotic diseases through cholesterol-reducing effects. Whether the latter exclusively mediate similar benefits, e.g. on hypertension, in the metabolic syndrome is unclear. We examined the effects of rosuvastatin on the components of this syndrome, as reproduced in mice doubly deficient in LDL receptors and leptin (DKO).

METHODS AND RESULTS

DKO received rosuvastatin (10 mg/kg/day or 20 mg/kg/day) or saline for 12 weeks. Saline-treated DKO mice had elevated blood pressure (BP) and nitric oxide-sensitive BP variability recorded by telemetry. Compared with saline, rosuvastatin (20 mg/kg/day) had no effect on weight gain and a minor effect on plasma cholesterol. Despite incomplete correction of insulin sensitivity, rosuvastatin fully corrected BP and its variability (P = 0.01), in conjunction with upregulation of PPARgamma (but not PPARalpha) in the aortic arch. Rosuvastatin similarly increased PPARgamma (P = 0.002) and SOD1 (P = 0.01) expression in isolated endothelial cells. Both GW9662, a PPARgamma-specific antagonist, and siRNA raised against PPARgamma abrogated rosuvastatin's effect, which was reproduced in PPARgamma- (but not PPARalpha-) dependent transactivation assays.

CONCLUSION

Beyond partial improvement in insulin sensitivity, rosuvastatin normalized BP homeostasis in obese dyslipidaemic mice independently of changes in body weight or plasma cholesterol. Upregulation of PPARgamma and SOD1 in the endothelium may be involved as a unique vasculoprotective effect of statin treatment.

Toll-like receptor 4 gene (Asp299Gly) polymorphism associates with carotid artery elasticity. The cardiovascular risk in young Finns study

OBJECTIVE

Early subclinical markers of atherosclerosis, such as carotid artery intima media thickness (IMT) and elasticity predict future coronary events. The G allele of the Toll-like receptor 4 (TLR-4) gene Asp299Gly polymorphism has been previously associated with decreased development of atherosclerosis and with lower risk of myocardial infractions. We wanted to examine the association of this polymorphism with carotid IMT and compliance in a population of young Finnish Caucasian adults.

METHODS

Carotid artery IMT and elasticity indices of 2201 study subjects who participated in a randomized multicenter study (cardiovascular risk in young Finns study) were measured with ultrasound. The genotyping was performed using the TaqMan 5'-nuclease assay.

RESULTS

According to multivariate linear regression analysis adjusted with potential confounders, the G allele carriers had significantly higher carotid arterial compliance, measured in increase of luminal diameter percentage in response to blood pressure rise of 10 mmHg, than did the AA homozygotes (beta=0.099 with 95% CI 0.029-0.169 and p=0.006). The difference between AA homozygotes and GG homozygotes was even more pronounced (beta=0.382 with 95% CI 0.119-0.644 and p=0.004). Variation in the TLR-4 genotype was not related with IMT. The results of the two independent study cohorts of Eastern and Western Finland were in accordance with the results of the whole combined study population.

CONCLUSION

The G allele of the TLR-4 gene Asp299Gly polymorphism is associated with increased carotid artery compliance in young adults. This beneficial effect of the G allele may reduce the risk of future cardiovascular events.

High aerobic capacity does not attenuate aortic stiffness in hypertensive subjects

BACKGROUND

It is unknown whether increased physical fitness reduces aortic stiffness in hypertensive individuals. The purpose of this cross-sectional study was to examine, in a cohort of community-dwelling subjects with no history of cardiac events, differences in the impact of aerobic capacity on aortic stiffness between normotensive and hypertensive subjects.

METHODS

The study sample included 275 subjects representing a large age range (21-85 years). Of these, 61 subjects (hypertensive cohort) were either hypertensive at enrollment or were taking antihypertensive medication. The remaining 214 subjects (normotensive cohort) had no history of hypertension. The study protocol included maximal cardiopulmonary exercise testing (determination of maximal oxygen consumption, or VO2max) and measurement of aortic wave velocity (AWV) using a novel magnetic resonance-based method.

RESULTS

Overall, the hypertensive cohort exhibited significantly elevated AWV in comparison to a subset of normotensives matched for age, sex, and aerobic fitness. Each cohort was then subdivided according to the percentage of predicted VO2max achieved (< 100% = "unfit," > or = 100% = "fit"). Differences between subgroups were assessed by unpaired t test. In the normotensive cohort, AWV was significantly lower in the fit versus the unfit subgroup. However, in the hypertensive cohort, AWV was not significantly different between fit and unfit subgroups nor between treated and untreated subgroups.

CONCLUSION

Unlike the situation in healthy normotensive subjects, higher peak aerobic capacity is not associated with lower aortic stiffness in hypertensive individuals.

Effect of long-term treatment with rosiglitazone on arterial elasticity and metabolic parameters in patients with Type 2 diabetes mellitus: a 2-year follow-up study

AIMS

Thiazolidinediones may influence the atherogenic process by improving cardiovascular risk factors. The present study was designed to determine the long-term effect of rosiglitazone on arterial compliance and metabolic parameters in patients with Type 2 diabetes.

METHODS

In an open-label, prospective study, 65 diabetic patients received rosiglitazone orally (4-8 mg/day) for 6 months. After 6 months, the patients continued an open follow-up study and were divided into two groups: group 1 included patients continuing rosiglitazone for 2 years, group 2 included patients discontinuing rosiglitazone and receiving other oral glucose-lowering agents. Lipid profile, glycated haemoglobin (HbA1c), insulin, C-peptide, fibrinogen, high-sensitivity-CRP and homeostasis model assessment-insulin resistance were measured. Arterial elasticity was assessed using pulse wave contour analysis.

RESULTS

In patients treated with rosiglitazone for 2 years: the large artery elasticity index (LAEI) increased from 10.0 +/- 4.6 to 13.9 +/- 4.7 ml/mmHg x 100 after 2 years (P = 0.003). The small artery elasticity (SAEI) index increased significantly from 3.2 +/- 1.2 to 5.1 +/- 1.9 (P < 0.0001). In patients who discontinued rosiglitazone: LAEI did not change after 6 months, but decreased from 12.1 +/- 5.4 to 8.9 +/- 3.9 ml/mmHg x 10 (P < 0.0001) at the end of 2 years. SAEI increased during the first 6 months of treatment, from 3.9 +/- 1.8 to 5.1 +/- 1.5 ml/mmHg x 100 (P < 0.0001) and decreased after discontinuation of rosiglitazone (P = 0.042).

CONCLUSIONS

Prolonged treatment with rosiglitazone improved arterial elasticity. However, significant deterioration in LAEI and SAEI was observed in patients who discontinued rosiglitazone. The beneficial vascular effect of rosiglitazone on arterial elasticity was independent of glycaemic control.

Relationships among renal function loss within the normal to mildly impaired range, arterial stiffness, inflammation, and oxidative stress

BACKGROUND AND OBJECTIVES

This study was conducted to clarify whether individuals with mildly impaired renal function show increased arterial stiffness, microinflammation, and oxidative stress as compared with those with normal renal function and also to examine the association of these parameters with the degree of GFR loss in middle-aged Japanese men with a low cardiovascular risk.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The brachial-ankle pulse wave velocity and plasma levels of C-reactive protein and lipid peroxides were measured in 1873 men (42 +/- 9 yr of age).

RESULTS

The brachial-ankle pulse wave velocity but not the plasma C-reactive protein or lipid peroxides, was increased in individuals with mildly impaired renal function. The GFR was significantly correlated with the brachial-ankle pulse wave velocity but not with the log-transformed values of C-reactive protein or lipid peroxides. Multivariate linear regression analysis demonstrated a significant relationship between the brachial-ankle pulse wave velocity and the GFR, independent of the conventional atherosclerotic risk factors. This relationship was significant even in individuals with GFR values within the "normal renal function" range. Thus, GFR loss seems to be more closely associated with arterial stiffness than with microinflammation and/or oxidative stress.

CONCLUSIONS

A weak but significant relationship was observed between the degree of GFR loss and arterial stiffness, even in individuals with GFR values within the normal renal function range. Therefore, increased arterial stiffness may underlie, at least in part, the elevated cardiovascular risk in individuals with mildly impaired renal function.

Genetic markers of vascular aging

Age is a powerful determinant of cardiovascular risk, being associated with a number of deleterious changes in the cardiovascular system. Increased arterial stiffness is an almost ubiquitous accompaniment of aging. However, there is significant variability in age-related arterial changes between individuals likely due, in part, to genetic factors. Measures of arterial stiffness such as pulse pressure and aortic pulse wave velocity have been shown to be heritable, indicating that genetic factors play a role in the interindividual variation of these phenotypes. Linkage analyses in related individuals have identified several genomic regions that may influence measures of arterial stiffness, and numerous association studies have investigated whether polymorphisms in candidate genes are related to this phenotype. Genome-wide association studies using 500,000 single nucleotide polymorphisms or more are now feasible and will accelerate the discovery of specific genetic polymorphisms that influence vascular aging/stiffness. Such findings will facilitate the development of novel therapies to retard vascular aging.

Arterial stiffness is independently associated with emphysema severity in patients with chronic obstructive pulmonary disease

RATIONALE

More patients with chronic obstructive pulmonary disease (COPD) die of cardiovascular causes than of respiratory causes, and patients with COPD have increased morbidity and mortality from stroke and coronary heart disease. Arterial stiffness independently predicts cardiovascular risk, is associated with atheromatous plaque burden, and is increased in patients with COPD compared with control subjects matched for cardiovascular risk factors. Elastin fragmentation and changes in collagen are found in the connective tissue of both emphysematous lungs and stiff arteries, but it is not known whether the severity of arterial stiffness in patients with COPD is associated with the severity of emphysema.

OBJECTIVES

To identify whether the extent of arterial stiffness is associated with emphysema severity.

METHODS

We performed a cross-sectional study in 157 patients with COPD.

MEASUREMENTS AND MAIN RESULTS

We measured pulse wave velocity (a validated measure of arterial stiffness), blood pressure, smoking pack-years, glucose, cholesterol, and C-reactive protein in 157 patients with COPD. We assessed emphysema using quantitative computed tomography scanning in a subgroup of 73 patients. We found that emphysema severity was associated with arterial stiffness (r = 0.471, P < 0.001). The association was independent of smoking, age, sex, FEV(1)% predicted, highly sensitive C-reactive protein and glucose concentrations, cholesterol-high-density lipoprotein ratio, and pulse oximetry oxygen saturations.

CONCLUSIONS

Emphysema severity is associated with arterial stiffness in patients with COPD. Similar pathophysiological processes may be involved in both lung and arterial tissue and further studies are now required to identify the mechanism underlying this newly described association.

Pulse pressure is an age-independent predictor of stroke development after cardiac surgery

Chronologic age is a strong predictor of adverse outcomes after cardiac surgery. The variability in age-related cardiovascular changes suggests that age may not be the most accurate predictor of adverse perioperative outcomes. Vascular stiffness has emerged as an important surrogate of vascular aging. In a retrospective review, we investigated the value of vascular stiffness, as assessed by brachial pulse pressure (PP) measurements, in predicting stroke in 703 patients (63.4% men and 36.6% women). Patients were followed for 348+/-215 days after cardiac surgery. We used a multivariable logistic model and unadjusted and adjusted Cox proportional-hazard models to assess the probability of stroke and the hazards of stroke over time. Stroke patients had a significantly higher PP (81.2 mm Hg versus 64.5 mm Hg; P=0.0006). In the logistic regression model, PP was an independent predictor of stroke development (unadjusted odds ratio: 1.35; 95% CI: 1.13 to 1.62, for every 10-mm Hg increase in PP; P=0.001). In the unadjusted and adjusted Cox models, PP again predicted stroke (hazard ratio: 1.32; 95% CI: 1.12 to 1.57; hazard ratio: 2.62; 95% CI: 1.49 to 4.60, respectively; P=0.001 for both) for every 10 mm Hg increase in PP. Age, gender, and diabetes were not independent predictors of stroke. Ejection fraction was inversely related to stroke in the adjusted model. Kaplan-Meier estimates and corresponding log-rank test indicated that the probability of stroke-free survival function was significantly lower (P=0.0067) in patients with PP >72 mm Hg versus <72 mm Hg. This analysis suggests that indices of vascular stiffness could be important predictors of neurologic complications.

Acute and Chronic Ventricular-Arterial Coupling in Systole and Diastole

Aging and hypertension lead to arterial remodeling and tandem increases in arterial (Ea) and ventricular (LV) systolic stiffness (ventricular-arterial [VA] coupling). Age and hypertension also predispose to heart failure with normal ejection fraction (HFnlEF), where symptoms during hypertensive urgencies or exercise are common. We hypothesized that: (1) chronic VA coupling also occurs in diastole, (2) acute changes in Ea are coupled with shifts in the diastolic and systolic pressure-volume relationships (PVR), and (3) diastolic VA coupling reflects changes in LV diastolic stiffness rather than external forces or relaxation. Old chronically hypertensive (OHT, n=8) and young normal (YNL, n=7) dogs underwent assessment of PVR (caval occlusion) and of aortic pressure, dimension, and flow, at baseline and during changes in afterload and preload. Concomitant changes in the slope/position of PVR were accounted for by calculating systolic (ESV 200 ) and diastolic (EDV 20 ) volumes at common pressures (capacitance). OHT displayed marked vascular remodeling. Indices reflecting the pulsatile component of Ea (aortic stiffness and systemic arterial compliance) were more impaired in OHT at any distending pressure. In both groups, acute increases in Ea were associated with decreases in ESV 200 and EDV 20 . However, at any load, OHT had lower ESV 200 and EDV 20 , associated with LV remodeling and myocardial endothelin activation. Acute changes in EDV 20 were not mediated by changes in relaxation or external forces. These observations provide insight into the mechanisms whereby arterial remodeling and acute and chronic VA coupling in both systole and diastole may predispose to and interact with increases in load to cause HFnlEF.

Differences in arterial compliance, microvascular function and venous capacitance between patients with heart failure and either preserved or reduced left ventricular systolic function

BACKGROUND

Up to 50% of patients with the clinical syndrome of heart failure have preserved left ventricular systolic function (HF-PSF). These patients may have abnormalities of ventriculo-vascular coupling, due to increased vascular and ventricular stiffness.

METHODS

We compared arterial compliance, microvascular vasodilator function and venous capacitance (VC) in 3 groups of patients (n=12 each) matched for the presence of coronary heart disease: 1) HF and preserved systolic function (HF-PSF), 2) HF and reduced systolic function (HF-RSF) and 3) controls (no HF, PSF). Arterial compliance was assessed by measuring aortic pulse wave velocity (PWV) with applanation tonometry. Cutaneous microvascular function was assessed using Laser Doppler imaging (LDI) coupled with iontophoresis of endothelium-dependent (acetylcholine) and -independent (sodium nitroprusside) vasodilators. VC was measured using venous occlusion plethysmography.

RESULTS

PWV was significantly higher in HF-PSF subjects than in both HF-RSF and control groups (10.7 [1.1], 8.9 [1.7] and 8.6 [2.1] m/s respectively, p<0.05). Acetylcholine and nitroprusside induced vasodilatation were equally impaired in HF-PSF and HF-RSF, as compared to controls (p<0.01). VC was higher in HF-RSF subjects compared with HF-PSF subjects (1.75 [0.41], 1.34 [0.34] ml/100 ml forearm vol. respectively, p<0.05).

CONCLUSIONS

These findings are consistent with a more marked increase in vascular stiffness in HF-PSF than in HF-RSF and suggest that arterial stiffness, dynamic vasodilator function and venous abnormalities may be implicated in the complex pathophysiology of HF-PSF.

Aortic distensibility and retinal arteriolar narrowing: the multi-ethnic study of atherosclerosis

Increased aortic stiffness and retinal arteriolar narrowing are subclinical vascular effects of chronic hypertension and predict future cardiovascular events. The relationship between these 2 vascular measures is uncertain and is examined in the Multi-Ethnic Study of Atherosclerosis. This cross-sectional analysis involves 3425 participants (aged 45 to 85 years) free of clinical cardiovascular disease. Retinal vascular caliber was quantified from digital retinal photographs using standardized protocols. Aortic distensibility was determined from chest MRI. After controlling for age, squared age, gender, race, study center, height, weight, heart rate, cigarette smoking, past and current systolic blood pressure, use of antihypertensive medications, diabetes, fasting glucose, lipid profile, and C-reactive protein, reduced aortic distensibility (first versus fourth distensibility quartile) was associated with increased odds of retinal arteriolar narrowing (odds ratio: 1.72; 95% CI: 1.15 to 2.58, comparing lowest to highest quartile of arteriolar caliber). Further adjustments for atherosclerotic measures (carotid intima-media thickness, coronary calcium score, and ankle brachial index) had minimal impact on this association (odds ratio: 1.70; 95% CI: 1.13 to 2.55). Reduced aortic distensibility was not associated with retinal venular caliber. We conclude that increased aortic stiffness is associated with retinal arteriolar narrowing, independent of measured blood pressure levels and vascular risk factors. These data suggest that changes in the microvasculature may play a role linking aortic stiffness with clinical cardiovascular events.

The influence of serum aldosterone and the aldosterone-renin ratio on pulse wave velocity in hypertensive patients

OBJECTIVE

The aldosterone-renin ratio (ARR) is widely used to screen for primary aldosteronism, and may reflect a relative excess of aldosterone secretion compared with renin secretion. Excess aldosterone may have a detrimental effect on vascular stiffness. We therefore hypothesized that ARR and aldosterone are independently correlated with pulse wave velocity (PWV) in hypertensive patients.

METHODS

The study consisted of 438 hypertensive patients. Serum aldosterone and plasma renin activity were measured in a sitting position using standard techniques. The PWV was determined by measuring the heart to femoral PWV (hfPWV) and brachial to ankle PWV with a VP-2000 pulse wave unit.

RESULTS

Group 1 was defined as patients with ARR of at least 20 (n = 53) with serum aldosterone >or= 12 ng/dl, while the remainder comprised group 2. Comparisons between the two groups reveal group 1 tended to have higher age, significantly higher proportion of women and higher systolic/diastolic blood pressure. Patients in group 1 also had a significantly higher index of central arterial stiffness (hfPWV 1048 +/- 202 vs 978 +/- 182, P = 0.010) compared with group 2. Multiple linear regression revealed that aldosterone, but not the ARR, is significantly associated with hfPWV but not brachial to ankle PWV, after controlling for age, systolic blood pressure and heart rate at the time of PWV measurement, body mass index, gender, low-density lipoprotein-cholesterol, triglyceride, high-density lipoprotein-cholesterol, blood pressure medication and statins.

CONCLUSIONS

Serum aldosterone is significantly associated with central aortic PWV in hypertensive patients. The results demonstrate a possible role for aldosterone in developing central aortic stiffness and increased PWV in hypertensive patients.

Arterial compliance and endothelial function

Decreased arterial compliance (increased stiffness) correlates with cardiovascular events, possibly due to increased cardiac afterload caused by more rapidly reflected pulse waves. Endothelium-derived mediators regulate vascular tone and structure, both of which can markedly influence arterial stiffness. Thus, increased arterial stiffness may be a mechanism by which endothelial dysfunction predisposes to complications of atherosclerosis. Conversely, therapeutic manipulation of endothelial mediators could reduce arterial stiffness and cardiovascular events. Techniques have been developed that use measures of arterial stiffness as an index of endothelial dilator function; these may provide unique prognostic information to identify high-risk subjects.

Severe left ventricular hypertrophy 1 year after transplant predicts mortality in cardiac transplant recipients

BACKGROUND

Left ventricular hypertrophy (LVH) is a known predictor of morbidity and mortality in patients with essential hypertension. The prevalence and significance of LVH in heart transplant recipients is unknown.

METHODS

Transthoracic echocardiograms were performed as part of a routine protocol 1 year after heart transplantation in 141 consecutive patients. Demographic and echocardiographic data were collected using patients' records and center-specific data from the Cardiac Transplant Research Database and analyzed to determine the prevalence and predictors of LVH at 1 year post-transplantation. Patients were divided into three groups based on left ventricular mass (LVM): normal (LVM <150 g); mild-moderate LVH (LVM 150 to 250 g); and severe LVH (LVM >250 g).

RESULTS

LVH was common at 1 year after heart transplantation, present in 83% of heart transplant recipients. Univariate predictors of severe LVH were increased body mass index (p < 0.01), pre-transplant diabetes mellitus (p = 0.02) and pre-transplant hypertension (p = 0.01). By multivariate analysis, pre-transplant hypertension was the only independent predictor of severe LVH (hazard ratio [HR] 2.3, 95% confidence interval [CI] 1.1 to 5.4, p = 0.05). Heart transplant recipients with severe LVH had significantly decreased survival, as compared to patients with normal LVM and mild-moderate LVH (p = 0.03). After multivariate analysis adjusting for age, race, gender, pre-transplant hypertension and diabetes, severe LVH remained a strong, independent predictor of mortality (HR 3.6, 95% CI 1.0 to 12.1, p = 0.04).

CONCLUSIONS

LVH is common at 1 year after heart transplantation and is a strong, independent predictor of increased mortality. Hypertension before transplantation is an independent predictor of the presence of severe LVH at 1 year after heart transplantation.

Measures of arterial stiffness and wave reflection are associated with walking distance in patients with peripheral arterial disease

We hypothesized that measures of arterial stiffness and wave reflection influence functional capacity of patients with peripheral arterial disease (PAD). Consecutive patients (n=106, 69+/-10 years, 66% men) referred for lower extremity arterial evaluation were studied. Radial artery pulse waveforms were obtained by applanation tonometry and an ascending aortic pressure waveform derived by a transfer function. Aortic augmentation index (AIx) is the difference between the first and second systolic peak of the ascending aortic pressure waveform indexed to the pulse pressure (PP) and T(r) is the reflected wave arrival time. Ankle-brachial index (ABI) and walking distance were measured as per laboratory protocol after excluding patients with non-compressible vessels (ABI>1.5) and severe PAD (ABI<0.5). To account for right-censoring of walking distances in patients completing the 5 min walk (n=56), we used survival analysis to identify variables associated with walking distance. Mean (+/-S.D.) values were: AIx, 31.2+/-10.9%; T(r), 134+/-18 ms; PP, 66.5+/-17.1 mmHg; ABI, 0.87+/-0.22; walking distance, 177+/-75 m. In both multivariable accelerated failure time (AFT) and Cox proportional-hazards models, older age, female sex, greater body mass index, lower ABI, and a measure of arterial stiffness (higher AIx and PP, lower T(r)) were associated with a lower walking distance. Higher AIx and lower T(r) were associated with a lower walking distance even after adjustment for PP as well as in the subset of patients with PAD (ABI<0.9 at rest or post-exercise, n=82). In conclusion, measures of arterial stiffness and wave reflection are associated with walking distance in patients with PAD and may be a target of therapy in such patients.

Regression of warfarin-induced medial elastocalcinosis by high intake of vitamin K in rats

Arterial calcification (AC) is generally regarded as an independent risk factor for cardiovascular morbidity and mortality. Matrix Gla protein (MGP) is a potent inhibitor of AC, and its activity depends on vitamin K (VK). In rats, inactivation of MGP by treatment with the vitamin K antagonist warfarin leads to rapid calcification of the arteries. Here, we investigated whether preformed AC can be regressed by a VK-rich diet. Rats received a calcification-inducing diet containing both VK and warfarin (W&K). During a second 6-week period, animals were randomly assigned to receive either W&K (3.0 mg/g and 1.5 mg/g, subsequently), a diet containing a normal (5 microg/g) or high (100 microg/g) amount of VK (either K1 or K2). Increased aortic calcium concentration was observed in the group that continued to receive W&K and also in the group changed to the normal dose of VK and AC progressed. Both the VK-rich diets decreased the arterial calcium content by some 50%. In addition, arterial distensibility was restored by the VK-rich diet. Using MGP antibodies, local VK deficiency was demonstrated at sites of calcification. This is the first study in rats demonstrating that AC and the resulting decreased arterial distensibility are reversible by high-VK intake.

Carotid artery compliance in users of plant stanol ester margarine

OBJECTIVE

To investigate the effects of stanol ester margarine use in healthy subjects on arterial compliance, endothelial function and intima-media thickness.

DESIGN

Case-control study comparing regular stanol ester margarine users to non-users.

SETTING

Occupational health service clinic.

SUBJECTS

We recruited 50 cases and 50 controls (mean age 51+/-8, range 26-65 years). All subjects were non-smokers and the study groups were matched for age and sex. As cases, we invited subjects who had been using regularly (daily) plant stanol ester margarine for a period of 2 years or longer. Non-invasive ultrasound was used to measure carotid artery compliance, carotid intima-media thickness and brachial artery flow-mediated endothelial dependent vasodilatation.

RESULTS

The carotid artery compliance was non-significantly higher in cases compared with controls, 1.84+/-1.02 vs 1.58+/-0.76 %/10 mm Hg (P=0.13). The difference in compliance became statistically significant (P=0.04) when the unbalance between the groups in family history of coronary artery disease and years of education were taken into account. There was also a significant dose-response relationship between stanol margarine use and carotid compliance, longer use being associated with higher compliance. Serum lipoproteins, blood pressure, flow-mediated dilation and intima-media thickness values did not differ between cases and controls.

CONCLUSION

These data raise the possibility that regular stanol ester margarine use may be associated with beneficial changes in arterial compliance. Intervention studies are needed to test this hypothesis and to reveal possible mechanisms.

Coronary hemodynamics and atherosclerotic wall stiffness: a vicious cycle

Local hemodynamic environment, including low shear stress and increased tensile stress, determines the localization, growth and progression of coronary atherosclerosis. As atherosclerotic lesions evolve, the diseased coronary arteries undergo local quantitative and qualitative changes in their wall, and progressively become stiff. Arterial stiffening amplifies the atherogenic local hemodynamic environment, initiating a self-perpetuating vicious cycle, which drives the progression of atherosclerosis and the formation of atherosclerotic plaque. In vivo evidence indicates that endothelial dysfunction is associated with arterial stiffness, an association that creates a challenging perspective of utilizing stiffness as an early marker of endothelial dysfunction and future atherosclerosis. Coronary stiffening is also associated with vascular remodeling, which is a major determinant of the natural history of atherosclerotic plaques. Thus, arterial stiffness may constitute a useful marker for the identification of the remodeling pattern, in particular expansive remodeling, which is closely associated with high-risk plaques. The early identification of endothelial dysfunction, or a high-risk plaque may enable the early adoption of preventive measures to improve endothelial function, or justify pre-emptive local interventions in high-risk regions to prevent future acute coronary syndromes. Further experimental and perspective clinical studies are needed for the investigation of these perspectives, whereas the development of new modalities for non-invasive and reliable assessment of coronary stiffness is anticipated to serve these studies.

Arterial stiffness and progression to hypertension in Japanese male subjects with high normal blood pressure

OBJECTIVES

This observational study was conducted to compare the significance of the relationship between arterial stiffness and progression to higher blood pressure categories among middle-aged Japanese men with high normal blood pressure (HNP), normal blood pressure (NRP) and optimal blood pressure (OPP).

METHODS AND RESULTS

During the 3-year observational period, 100 subjects with HNP developed hypertension (n=475; 42 +/- 9 years), and 175 of those with normal NRP (n=581; 41 +/- 8 years) and 249 of those with OPP (n=702; 39 +/- 8 years) showed progression to higher blood pressure categories. A binary logistic regression analysis adjusted for known risk factors revealed that values of the brachial-ankle pulse wave velocity, a surrogate marker of arterial stiffness, in the highest quartile, as compared with those in the lowest quartile, obtained at the start of the study were significantly predictive of the progression to hypertension [adjusted odds ratio = 9.4 (95% confidence interval, 3.0-29.8), P < 0.01]. The predictive value of this parameter for progression to higher blood pressure categories in subjects with HNP was more significant than that in those with NRP or OPP.

CONCLUSIONS

Increased arterial stiffness and elevated blood pressure may be mutually causally related, and it appears that the significance of this relationship may increase with increasing blood pressure, even in subjects without hypertension. Assessment of arterial stiffness may be more reliable for predicting the progression to hypertension in cases of HNP than in cases with NRP or OPP.

Relation of Proximal Aorta Stiffness to Left Ventricular Diastolic Function in Patients with End-Stage Renal Disease

AIM

We examined the relationship between proximal aortic stiffness and left ventricular (LV) diastolic function in patients with end-stage renal disease (ESRD).

PATIENTS AND METHODS

We studied 99 patients with ESRD with preserved LV ejection fraction greater than 50% and 83 controls. We assessed the aorta stiffness by measuring the pulse wave velocity (PWV) in the proximal aorta (PWVr) using a novel echo application and in the descending aorta (PWVcf) using a foot-to-foot method. Patients were classified according to LV diastolic filling pattern into normal, delayed relaxation, pseudonormal, and restrictive filing pattern groups.

RESULTS

Patients with ESRD had increased PWVr, PWVcf, and LV mass index (LVMI) compared with controls (all P < .0001). Patients with advanced diastolic dysfunction showed increased PWVr (P < .001) and PWVcf (P = .007) compared with those with mild diastolic dysfunction. PWVr was correlated to PWVcf (r = 0.74, P < .001) in patients with ESRD. Multivariate linear regression analysis revealed that PWVr was independently correlated to both LVMI and LV diastolic filling pattern.

CONCLUSIONS

Increased LVMI, advanced LV diastolic dysfunction, and generalized aortic stiffening were observed in patients with ESRD. Proximal aorta stiffness is associated with both increased LVMI and advanced LV diastolic dysfunction in those patients.

The effects of changes in the metabolic syndrome detection status on arterial stiffening: a prospective study

We conducted a prospective study to examine the effects of alterations of the metabolic syndrome detection status on the rate of progression of arterial stiffness, which is recognized as a marker of arterial damage and an indicator of cardiovascular risk. Brachial-ankle pulse wave velocity as an index of arterial stiffening was recorded twice over a 3-year period in 2080 Japanese men (age, 42 +/- 9 years). At the start of the prospective study, pulse wave velocity was higher in the subjects with metabolic syndrome (n=125) than in those without metabolic syndrome (n=1,955) even after adjusting for mean blood pressure. The annual rate of increase of the pulse wave velocity was higher in the group with persistent metabolic syndrome (27 +/- 51 cm/s/year, n=71) than in the group with regression of metabolic syndrome (6 +/- 39 cm/s/year, n=54) or the group in which metabolic syndrome was absent (13 +/- 37 cm/s/year, n=1843; p < 0.05) after adjustment for changes in blood pressure. In conclusion, the changes in the metabolic syndrome detection status of the subjects during the study period affected the annual rate of progression of arterial stiffening, and persistent metabolic syndrome during the study period was associated with acceleration of arterial stiffening in middle-aged Japanese men. On the other hand, resolution of metabolic syndrome may be associated with attenuation of the progression of arterial damage. Therefore, the increased cardiovascular risk associated with the presence of metabolic syndrome may be at least partly mediated by acceleration of the progression of arterial stiffening.

Relationship between Arterial Stiffness and the Risk of Coronary Artery Disease in Subjects with and without Metabolic Syndrome

We examined the influence of metabolic syndrome (MetS) on the relationship between arterial stiffness and the risk of coronary artery disease (CAD). In 396 subjects (age, 63+/-11 years) who underwent coronary angiography, multiple linear regression analysis demonstrated that the brachial-ankle pulse wave velocity (PWV), but not the presence of MetS, was a significant determinant of the number of diseased coronary arteries (beta=0.10, p<0.05), even though both the brachial-ankle PWV and the number of diseased coronary arteries were higher in subjects with MetS (n=100) than in those without MetS (n=296). However, in subjects with MetS, multiple linear regression analysis demonstrated that the brachial-ankle PWV was not a significant determinant of the number of diseased coronary arteries. The brachial-ankle PWV values were classified into tertile ranges in subjects with and without MetS. The number of diseased coronary arteries increased significantly with an increase in the tertile number of the brachial-ankle PWV in the subjects without MetS (tertile 1=1.00+/-0.86, tertile 2=1.29+/-1.01, and tertile 3=1.45+/-1.05), but not in those with MetS. In conclusion, the results of this study suggest that arterial stiffness is a marker of the risk of CAD in subjects without MetS, whereas in subjects with MetS, the syndrome may directly produce clinically significant atherosclerotic stenosis of the coronary arteries independent of its significant promotion of the development of coronary atherosclerosis via an increase of arterial stiffness.

Heart Rate Elevation Precedes the Development of Metabolic Syndrome in Japanese Men: A Prospective Study

This observational study of Japanese men without metabolic syndrome (MetS) (age: 41+/-8 years) was conducted to clarify whether or not heart rate elevation precedes the development of full-blown MetS. MetS was defined based on two modifications of the criteria of the Japanese Expert Committee on the Diagnosis and Classification of Metabolic Syndrome. Premetabolic syndrome subjects were defined as those having one component of MetS with increased body mass index (BMI). Among the subjects without MetS (n=1,859 when the BMI criterion was >or=25 and n=2,020 when the BMI criterion was >or=27.5), the incidence of progression to full-blown MetS by the time of the second examination at the end of the 3-year study period was higher in the subjects with premetabolic syndrome than in those without it. The receiver-operator characteristic curve analysis and binary logistic regression analysis revealed that the odds ratio (OR) of a heart rate >or=69 beats/min at the first examination for progression to full-blown MetS by the time of the second examination was significant in subjects with premetabolic syndrome (BMI>or=25: OR=3.64 [1.22-10.88]; BMI>or=27.5: OR=3.67 [1.28-10.55]; p<0.05). Thus, heart rate elevation appears to precede the development of full-blown MetS in subjects with premetabolic syndrome. Heart rate seems to be a simple and useful marker for predicting the progression to full-blown MetS of middle-aged Japanese men with premetabolic syndrome.

Microgravity-induced changes in aortic stiffness and their role in orthostatic intolerance

Microgravity (microG)-induced orthostatic intolerance (OI) in astronauts is characterized by a marked decrease in cardiac output (CO) in response to an orthostatic stress. Since CO is highly dependent on venous return, alterations in the resistance to venous return (RVR) may be important in contributing to OI. The RVR is directly dependent on arterial compliance (C(a)), where aortic compliance (C(ao)) contributes up to 60% of C(a). We tested the hypothesis that microG-induced changes in C(a) may represent a protective mechanism against OI. A retrospective analysis on hemodynamic data collected from astronauts after 5- to 18-day spaceflight missions revealed that orthostatically tolerant (OT) astronauts showed a significant decrease in C(a) after spaceflight, while OI astronauts showed a slight increase in C(a). A ground-based animal model simulating microG, hindlimb-unweighted rats, was used to explore this phenomenon. Two independent assessments of C(ao), in vivo pulse wave velocity (PWV) of the thoracic aorta and in vitro pressure-diameter squared relationship (PDSR) measurements of the excised thoracic aorta, were determined. PWV showed a significant increase in aortic stiffness compared with control, despite unchanged blood pressures. This increase in aortic stiffness was confirmed by the PDSR analysis. Thus both actual microG in humans and simulated microG in rats induces changes in C(ao). The difference in C(a) in OT and OI astronaut suggests that the microG-induced decrease in C(a) is a protective adaptation to spaceflight that reduces the RVR and allows for the maintenance of adequate CO in response to an orthostatic stress.

Genetic Determinants of Systolic and Pulse Pressure in an Intercross Between Normotensive Inbred Rats

By continuous monitoring of abdominal aortic blood pressure via telemetry in conscious rats, we have observed that systolic, diastolic, and pulse pressures of male Brown-Norway rats were all significantly lower than that of male Wistar-Kyoto rats, despite the fact that all of the values in both strains were within normotensive ranges. Further analyses performed in 166 animals from the progeny of an F2 intercross between Brown-Norway and Wistar-Kyoto rats revealed that, despite a high correlation between systolic blood pressure and diastolic blood pressure, there was no correlation between pulse pressure and diastolic blood pressure, and the value of the correlation between systolic blood pressure and pulse pressure was lower than that of systolic blood pressure with diastolic blood pressure. Two major and highly significant (P<0.001) quantitative trait loci linked to pulse pressure were found on chromosome 4 (Pp1) and 16 (Pp2). Only suggestive quantitative trait loci were found for systolic blood pressure, but the strongest one (Sbp1) had the same peak and linkage probability profile as Pp1. Altogether, these data show that genetic determinants affecting pulse pressure in normotensive animals are either stronger or independent from the ones affecting systolic blood pressure and are of interest in light of evidence showing that pulse pressure is highly heritable in humans and that elevated pulse pressure is a predictor of cardiovascular risk.

Ventricular Pump Function in Heart Failure with Normal Ejection Fraction: Insights from Pressure-Volume Measurements

The syndrome of heart failure in the setting of normal ejection fraction (HFNEF) is manifest in a clinically heterogeneous group of patients with multiple and varied comorbid conditions. In this report, we review available data derived from pressure-volume (PV) analyses in patients with and in animal models of HFNEF. Pressure-volume analysis of ventricular function is challenging in the clinical setting but provides unique insights into the systolic, diastolic, and overall pumping characteristics of the heart. Results of such analyses have thus far been limited to small cohorts of patients but suggest that different cohorts of patients with HFNEF having PV relations that imply different pathophysiologic mechanisms exist. This emphasizes the need to take a view of this syndrome, which extends beyond diastolic dysfunction, particularly when it comes to proposing and investigating therapeutic targets. We therefore propose that progress can be made in advancing therapeutics for HFNEF if it is appreciated that different underlying pathophysiologic mechanisms may be important in different cohorts and if attention expands beyond diastolic dysfunction as the sole target. Similar to the success that was achieved in advancing therapeutics for systolic heart failure when attention shifted away from the heart to the neurohormonal and renal axes, our interpretation of data in human beings and in animal models suggests that addressing similar targets (perhaps not in exactly the same manner) may prove to be fruitful, at least for some patients with HFNEF as well.

Cellular mechanisms and signalling pathways activated by high glucose and AGE-albumin in the aortic endothelium

This review summarizes evidence on the effect of excess circulating glucose concentration and AGE-albumin on the aortic endothelial cells (ECs) phenotype, transport function, and expression of signalling molecules. The recent reports on the ECs dysfunction in diabetes are briefly reviewed, to provide a broader view on the link between ECs structural changes, functional alterations, and the underlying biochemical mechanisms. The original results emerging from streptozotocin-injected mice and human aortic endothelial cells grown in high (25 mM) glucose concentration are presented. Compared to physiological condition, in diabetes aortic ECs switch to a biosynthetic phenotype, present an increased number of caveolae, and enhance (by approximately 20%) transcytosis of AGE-albumin (AGE-Alb). In cultured ECs, 25 mM glucose induces approximately 2.6 fold increase in pSTAT-3 and pERK1 and approximately 1.8 fold increase in pERK2; further exposure to 5 microM AGE-Alb causes approximately 4.3 fold increase in pERK1/2 (vs. 5 mM glucose). Together, these data may explain the phenotypic change, enhanced permeability, and proliferation of aortic ECs in diabetic conditions.

Rheumatoid arthritis is associated with increased aortic pulse-wave velocity, which is reduced by anti-tumor necrosis factor-alpha therapy

BACKGROUND

Rheumatoid arthritis (RA) is associated with increased cardiovascular risk, which is not explained by traditional cardiovascular risk factors but may be due in part to increased aortic stiffness, an independent predictor of cardiovascular mortality. In the present study, our aim was to establish whether aortic stiffness is increased in RA and to investigate the relationship between inflammation and aortic stiffness. In addition, we tested the hypothesis that aortic stiffness could be reduced with anti-tumor necrosis factor-alpha (TNF-alpha) therapy.

METHODS AND RESULTS

Aortic pulse-wave velocity (PWV), augmentation index, and blood pressure were measured in 77 patients with RA and in 142 healthy individuals. Both acute and chronic inflammatory measures and disease activity were determined. The effect of anti-TNF-alpha therapy on PWV and endothelial function was measured in 9 RA patients at 0, 4, and 12 weeks. Median (interquartile range) aortic PWV was significantly higher in subjects with RA than in control subjects (8.35 [7.14 to 10.24] versus 7.52 [6.56 to 9.18] m/s, respectively; P = 0.005). In multiple regression analyses, aortic PWV correlated independently with age, mean arterial pressure, and log-transformed C-reactive protein (R2 = 0.701; P < 0.0001). Aortic PWV was reduced significantly by anti-TNF-alpha therapy (8.82+/-2.04 versus 7.94+/-1.86 versus 7.68+/-1.56 m/s at weeks 0, 4, and 12, respectively; P < 0.001); concomitantly, endothelial function improved.

CONCLUSIONS

RA is associated with increased aortic stiffness, which correlates with current but not historical measures of inflammation, suggesting that increased aortic stiffness may be reversible. Indeed, anti-TNF-alpha therapy reduced aortic stiffness to a level comparable to that of healthy individuals. Therefore, effective control of inflammation may be of benefit in reducing cardiovascular risk in patients with RA.

RELATIONSHIP BETWEEN ARTERIAL STIFFNESS AND GLUCOSE METABOLISM IN WOMEN WITH METABOLIC SYNDROME

1. Cardiovascular risk factors associated with the metabolic syndrome affect vascular functions adversely. The aim of the present study was to assess the relationship between parameters of glucose homeostasis and arterial stiffness in women with characteristics of the metabolic syndrome. 2. Twenty post-menopausal women participated in a cross-sectional study in which systemic arterial compliance (SAC) and plasma glucose, lipids and glycosylated haemoglobin (HbA1c) were measured while subjects were maintained on a diet high in fibre, raised in protein and reduced in saturated fat. 3. Regression analysis suggested that mean ( +/-SD) fasting glucose of 5.9 +/- 1.7 mmol/L, glucose levels 2 h after a 75 g glucose load of 6.8 +/- 3.6 mmol/L, systolic blood pressure of 131 +/- 12 mmHg and HbA1c of 5.3 +/- 1.7% predicted SAC negatively. The following correlations were obtained between SAC and: (i) fasting glucose: R = -0.49, P = 0.028; (ii) 2 h glucose level post-glucose load: R = -0.42, P = 0.064; (iii) HbA1c: R = -0.42, P = 0.056; and (iv) systolic blood pressure: R = -0.55, P = 0.012. 4. Relationships between SAC and fasting glucose and systolic blood pressure were significantly independent of each other. There was no evidence of relationships between SAC and any plasma lipid parameter (other than a trend in relation to plasma triglyceride), bodyweight or waist circumference. 5. In conclusion, in post-menopausal women with metabolic syndrome, fasting plasma glucose and systolic blood pressure, and possibly HbA1c and the 2 h glucose post-glucose load, predicted increased arterial stiffness.

White matter grade and ventricular volume on brain MRI as markers of longevity in the cardiovascular health study

High white matter grade (WMG) on magnetic resonance imaging (MRI) is a risk factor for dementia, stroke and disability. Higher ventricular size is a marker of brain "atrophy." In the Cardiovascular Health Study (CHS) (n=3245) mean age 75 years, 50% black and 40% men, we evaluated WM and ventricular grade (VG), total, cardiovascular and noncardiovascular mortality and longevity before and after adjusting for numerous determinants of longevity over an approximate 10-12 years of follow-up. A low WMG and VG was a marker for low total, cardiovascular and noncardiovascular mortality and for increased longevity over 10+ years of follow-up. We estimated that a 75-year-old with WMG below median would have about a 5-6 years greater longevity and for VG about 3 years, than above the median even after adjustment for numerous risk factors. Low WMG and VG on MRI is a powerful determinant of long-term survival among older individuals.

From vulnerable plaque to vulnerable patient--Part III: Executive summary of the Screening for Heart Attack Prevention and Education (SHAPE) Task Force report

Screening for early-stage asymptomatic cancers (eg, cancers of breast and colon) to prevent late-stage malignancies has been widely accepted. However, although atherosclerotic cardiovascular disease (eg, heart attack and stroke) accounts for more death and disability than all cancers combined, there are no national screening guidelines for asymptomatic (subclinical) atherosclerosis, and there is no government- or healthcare-sponsored reimbursement for atherosclerosis screening. Part I and Part II of this consensus statement elaborated on new discoveries in the field of atherosclerosis that led to the concept of the "vulnerable patient." These landmark discoveries, along with new diagnostic and therapeutic options, have set the stage for the next step: translation of this knowledge into a new practice of preventive cardiology. The identification and treatment of the vulnerable patient are the focuses of this consensus statement. In this report, the Screening for Heart Attack Prevention and Education (SHAPE) Task Force presents a new practice guideline for cardiovascular screening in the asymptomatic at-risk population. In summary, the SHAPE Guideline calls for noninvasive screening of all asymptomatic men 45-75 years of age and asymptomatic women 55-75 years of age (except those defined as very low risk) to detect and treat those with subclinical atherosclerosis. A variety of screening tests are available, and the cost-effectiveness of their use in a comprehensive strategy must be validated. Some of these screening tests, such as measurement of coronary artery calcification by computed tomography scanning and carotid artery intima-media thickness and plaque by ultrasonography, have been available longer than others and are capable of providing direct evidence for the presence and extent of atherosclerosis. Both of these imaging methods provide prognostic information of proven value regarding the future risk of heart attack and stroke. Careful and responsible implementation of these tests as part of a comprehensive risk assessment and reduction approach is warranted and outlined by this report. Other tests for the detection of atherosclerosis and abnormal arterial structure and function, such as magnetic resonance imaging of the great arteries, studies of small and large artery stiffness, and assessment of systemic endothelial dysfunction, are emerging and must be further validated. The screening results (severity of subclinical arterial disease) combined with risk factor assessment are used for risk stratification to identify the vulnerable patient and initiate appropriate therapy. The higher the risk, the more vulnerable an individual is to a near-term adverse event. Because <10% of the population who test positive for atherosclerosis will experience a near-term event, additional risk stratification based on reliable markers of disease activity is needed and is expected to further focus the search for the vulnerable patient in the future. All individuals with asymptomatic atherosclerosis should be counseled and treated to prevent progression to overt clinical disease. The aggressiveness of the treatment should be proportional to the level of risk. Individuals with no evidence of subclinical disease may be reassured of the low risk of a future near-term event, yet encouraged to adhere to a healthy lifestyle and maintain appropriate risk factor levels. Early heart attack care education is urged for all individuals with a positive test for atherosclerosis. The SHAPE Task Force reinforces existing guidelines for the screening and treatment of risk factors in younger populations. Cardiovascular healthcare professionals and policymakers are urged to adopt the SHAPE proposal and its attendant cost-effectiveness as a new strategy to contain the epidemic of atherosclerotic cardiovascular disease and the rising cost of therapies associated with this epidemic.

Comparative effects of pitavastatin and probucol on oxidative stress, Cu/Zn superoxide dismutase, PPAR-gamma, and aortic stiffness in hypercholesterolemia

Reactive oxygen species-scavenging enzyme Cu/Zn superoxide dismutase (SOD) regulated by peroxisome proliferator-activated receptors (PPARs) plays an important role in vascular responsiveness. However, it remains unknown whether statin restores vascular dysfunction through the activation of reactive oxygen species-scavenging enzymes in vivo. We hypothesized that pitavastatin restores vascular function by modulating oxidative stress through the activation of Cu/ZnSOD and PPAR-gamma in hypercholesterolemia. New Zealand White male rabbits were fed either normal chow or a 1% cholesterol (CHO) diet for 14 wk. After the first 7 wk, the CHO-fed rabbits were further divided into three groups: those fed with CHO feed only (HC), those additionally given pitavastatin, and those additionally given an antioxidant, probucol. The extent of atherosclerosis was assessed by examining aortic stiffness. When compared with the HC group, both the pitavastatin and probucol groups showed improved aortic stiffness by reducing aortic levels of reactive oxidative stress, nitrotyrosine, and collagen, without affecting serum cholesterol or blood pressure levels. Pitavastatin restored both Cu/ZnSOD activity (P < 0.005) and PPAR-gamma expression and activity (P < 0.01) and inhibited NAD(P)H oxidase activity (P < 0.0001) in the aorta, whereas probucol inhibited NAD(P)H oxidase activity more than did pitavastatin (P < 0.0005) without affecting Cu/ZnSOD activity or PPAR-gamma expression and activity. Importantly, Cu/ZnSOD activity was positively correlated with the PPAR-gamma activity in the aorta (P < 0.005), both of which were negatively correlated with aortic stiffness (P < 0.05). Vascular Cu/ZnSOD and PPAR-gamma may play a crucial role in the antiatherogenic effects of pitavastatin in hypercholesterolemia in vivo.

Improved right ventricular-vascular coupling during active pulmonary hypertension

Right ventricular adaptation to pulmonary hypertension (PH) is an important prognostic factor. Pulmonary artery (PA) smooth muscle activation attenuates arterial dysfunction during acute PH. We investigated the role of the pulmonary artery vascular smooth muscle activation on the right ventricular-vascular coupling during acute PH. PA flow, pressure, and diameter, right ventricular and aortic pressures were recorded in six anesthetized sheep. Acute PH was induced by phenylephrine (APH) and PA mechanical constriction (PPH). We calculated the PA buffering function, the incremental elastic modulus and pulmonary vascular compliance. Pulmonary vascular impedance and right ventricular hydraulic power were calculated through Fourier approach. We also quantified the magnitude and timing of the reflected wave. Right ventricular-vascular coupling was assessed by the energy transmission ratio. Pulmonary buffering function and vascular compliance increased (P<0.05) and arterial wall stiffness decreased (P<0.05) during APH with respect to PPH. Although total input resistance increased and reflected wave came back earlier during PH states (P<0.05), only PPH produced a rightward shift of the pulmonary impedance and a more prominent reflected wave. Accordingly, APH determined a minor increase of total hydraulic power with a smaller pulsatile to total power ratio and energy transmission ratio (P<0.05). In conclusion, isobaric PA vasoconstriction prevents the pulsatile hydraulic load to increase by preserving the PA buffering function and the reflected wave magnitude. Thus, vascular smooth muscle activation of the main PA improves the energy transfer from the right ventricle to the hypertensive pulmonary circulation, and this may play relevant role in the right ventricular adaptation to acute PH.

Central and peripheral arterial stiffness in patients after surgical repair of tetralogy of Fallot: implications for aortic root dilatation

OBJECTIVES

To test the hypotheses that (1) the central conduit arteries stiffen preferentially over the peripheral conduit arteries in patients with repaired tetralogy of Fallot (ToF); and (2) central arterial stiffening is related to aortic root dilatation.

DESIGN AND PATIENTS

Heart-femoral pulse wave velocity (PWV), femoral-ankle PWV, carotid augmentation index and body surface area-adjusted aortic sinotubular dimension were determined in 31 children after ToF repair and compared with those in 31 age-matched controls after left-to-right shunt repair. In addition, the PWVs and augmentation index were related to the sinotubular junction dimension.

SETTINGS

Tertiary paediatric cardiac centre.

RESULTS

Compared with controls, patients had significantly greater heart-femoral PWV (mean 666 (SD 151) v 587 (81) cm/s, p = 0.021) and carotid augmentation index (-14.1 (17.0)% v -25.2 (14.6)%, p = 0.016), whereas the right (888 (202) v 845 (207) cm/s, p = 0.42) and left (918 (227) v 851 (215) cm/s, p = 0.25) femoral-ankle PWVs were similar between the two groups. The sinotubular junction z score of patients was significantly greater than that of controls (4.7 (1.5) v 1.1 (1.4), p < 0.001). Univariate analysis showed that the sinotubular junction z score correlated positively with heart-femoral PWV (r = 0.43, p = 0.001) and carotid augmentation index (r = 0.46, p = 0.001). Multiple linear regression similarly identified heart-femoral PWV (beta = 0.30, p = 0.04) and carotid augmentation index (beta = 0.31, p = 0.04) (model R(2) = 0.26) as significant determinants of sinotubular junction z score.

CONCLUSIONS

The aorta stiffens in patients with repaired ToF, which may contribute to progressive dilatation of the aortic root in the long term.

The role of pulse pressure in the hemodynamic control of hypertension: exploring the link to cardiovascular remodeling

OBJECTIVE

To correlate the values in the basic blood pressure groups presented in the JNC 7th with the computed values of the Noninvasive Hemodynamic Analyzer (NHA) and to demonstrate the pathophysiological alterations by three proportional hypertensive models.

DESIGN

Hemodynamic values of each of the blood pressure groups presented in the JNC 7th are tabulated for men between 20 and 50 years of age with particular interest in Pulse Pressure.

PATIENTS

Idealized patients were used in the three groups of the proportional hypertensive models.

VALIDITY

Previous studies demonstrated that the Bias, Precision, and Accuracy of Cardiac Output measurement, compared to Thermodilution technique, resulted in statistically acceptable clinical values.

CONCLUSION

This research has successfully demonstrated, with the use of the NHA, the leading role of Pulse Pressure in normal and hypertensive patients. We are convinced that this technique can be used as an economical and time-saving alternative screening tool in clinical medicine.

Lactadherin binds to elastin--a starting point for medin amyloid formation?

Medin amyloid is found in the medial layer of the aorta in almost 100% of the Caucasian population over 50 years of age. The medin fragment is 5.5 kDa and derives from the C2-like domain of the precursor protein lactadherin. We have previously reported immunohistochemical findings showing that medin amyloid co-localizes with elastic fibers of arteries and herein we show that lactadherin also is associated with elastic structures of human aortic material. In addition, results from in vitro binding assays demonstrate that both medin and lactadherin bind to tropoelastin in a concentration-dependent fashion, suggesting that the lactadherin-tropoelastin interaction is mediated via the medin domain. It is possible that lactadherin, which is a cell adhesion protein, in this way connects smooth muscle cells to the elastic fibers of arteries. Given that both medin and lactadherin interact with elastic fibers, elastin is probably an important component in the formation of medin amyloid.

An isoflavone metabolite reduces arterial stiffness and blood pressure in overweight men and postmenopausal women

OBJECTIVES

Isoflavones reduce arterial stiffness, a predictor of cardiovascular events. Whether metabolites of isoflavones have similar bioactivity is unknown. The effect of supplemental trans-tetrahydrodaidzein (THD) a metabolite of daidzein on pulse wave velocity (PWV), a measure of arterial stiffness was tested in overweight men and postmenopausal women.

METHODS

25 subjects, 11 postmenopausal women, 14 men (age, 57 [7] years; body mass index, 30.3 [4.7]kg/m(2); mean [S.D.]) participated in a double-blind, randomized, cross-over trial of THD versus placebo.

DESIGN

2 weeks run-in followed by either THD 1g daily or placebo, each intervention 5 weeks. Aorta-femoral artery PWV, blood pressure and plasma lipids were measured after run-in, THD and placebo.

RESULTS

PWV was significantly reduced (signifying diminished central arterial stiffness): medians (25th and 75th%), placebo 9.9 m/s (8.7, 11.1), THD 8.8m/s (7.9, 10.9); RM ANOVA P=0.023, with Tukey procedure P<0.05. Systolic blood pressure was significantly reduced: means (S.D.), placebo 125.6 (14.7), THD 121.3 (12.2)mmHg; Tukey P<0.05. Plasma cholesterol, triglyceride and LDL cholesterol did not differ significantly. Absorption of THD >80% substantially exceeded that of parent isoflavones.

CONCLUSION

A metabolite normally formed after consumption of isoflavones (formononetin, daidezein), taken orally, reduced blood pressure and central arterial stiffness indicating reduced cardiovascular risk.