Higher PWV Research Articles

Insulin resistance and arterial stiffness in healthy adolescents and young adults

Increased arterial stiffness is a risk factor for adverse cardiovascular events in adults with obesity-related insulin resistance (IR) or type 2 diabetes mellitus. Adolescents with type 2 diabetes have stiffer vessels. Whether stiffness is increased in obesity/IR in youth is not known. We sought to determine if IR was a determinant of arterial stiffness in youth, independent of obesity and cardiovascular risk factors. We measured cardiovascular risk factors, IR, adipocytokines and arterial stiffness (brachial artery distensibility [BrachD], pulse wave velocity [PWV]) and wave reflection (augmentation index [AIx]) in 343 adolescents and young adults without type 2 diabetes (15-28 years old, 47% male, 48% non-white). Individuals <85th percentile of BMI were classified as lean (n = 232). Obese individuals were grouped by HOMA index as not insulin resistant (n = 46) or insulin resistant (n = 65) by the 90th percentile for HOMA for lean. Mean differences were evaluated by ANOVA. Multivariate models evaluated whether HOMA was an independent determinant of arterial stiffness. Risk factors deteriorated from lean to obese to obese/insulin resistant (all p ≤ 0.017). Higher AIx, lower BrachD and higher PWV indicated increased arterial stiffness in obese and obese/insulin-resistant participants. HOMA was not an independent determinant. Age, sex, BMI and BP were the most consistent determinants, with HDL-cholesterol playing a role for BrachD and leptin for PWV (AIx R²= 0.34; BrachD R² = 0.37; PWV R² = 0.40; all p ≤ 0.02). Although IR is associated with increased arterial stiffness, traditional cardiovascular risk factors, especially obesity and BP, are the major determinants of arterial stiffness in healthy young people.

Low Achieved Diastolic Pressure in Tightly Controlled Mid-Older Hypertensive Subjects Is Associated With Favorable Arterial Properties

Low diastolic blood pressure (DBP) is commonly seen in well-controlled hypertensive subjects. We evaluated arterial properties in 53 hypertensive subjects with low on-treatment DBP (<70 mm Hg; LODP), 54 subjects with normal BP and spontaneously low DBP (SLDP), and 52 treated hypertensive subjects with DBP ≥70 mm Hg (HNDP). The two measures of large artery rigidity, pulse wave velocity and augmentation index, were similar in LODP and SLDP groups. In contrast, the HNDP group had higher PWV and the lowest large and small artery compliance in comparison with all other groups. Low on-treatment DBP is associated with favorable arterial properties in mid-older hypertensive patients.

Hypertrophic remodeling and increased arterial stiffness in patients with intracranial aneurysms

Objective Because an underlying arteriopathy might contribute to the development of intracranial aneurysms (IAs), we assessed the elastic properties of proximal conduit arteries in patients with IA. Methods In 27 patients with previous ruptured IA and 27 control subjects matched for age, gender and BMI, we determined arterial pressure, internal diameter, intima-media thickness (IMT), circumferential wall stress (CWS) and elastic modulus (wall stiffness) in common carotid arteries using applanation tonometry and echotracking. Moreover, carotid augmentation index (AIx, arterial wave reflections) and carotid-to-femoral pulse wave velocity (PWV, aortic stiffness) were assessed. Results Compared with controls, patients with IA exhibited higher brachial and carotid systolic and diastolic blood pressures, with similar brachial but higher carotid artery pulse pressure (35 ± 6 mm Hg vs. 41 ± 8 mm Hg, P = 0.014). Moreover, patients have higher PWV (7.8 ± 1.2 m s −1 vs. 8.3 ± 1.1 m s −1, P = 0.048) and AIx (15.8 ± 10.8% vs. 21.1 ± 8.5%, P < 0.001) which contributes to increase carotid blood pressures. Furthermore, carotid IMT was higher in patients (546 ± 64 μm vs. 642 ± 70 μm, P < 0.001) without difference in diameter suggesting an adaptive hypertrophy. However, patients display a lower CWS (61.6 ± 9.2 kPa vs. 56.9 ± 10.3 kPa, P = 0.007) and no correlation between IMT and pulse pressure ( r = 0.152, P = NS) in contrast to controls ( r = 0.539, P < 0.001) showing the contribution of a pressure-independent process. Finally, despite this lesser CWS, elastic modulus was increased in patients (310 ± 105 kPa vs. 383 ± 174 kPa, P = 0.026). Conclusion This study demonstrates that patients with IA display a particular carotid artery phenotype with an exaggerated hypertrophic remodeling and altered elastic properties. Thus, a systemic arteriopathy might contribute, together with the arterial wall fatiguing effect of the increased pulsatile stress, to the pathogenesis of IA.

I030 Young spontaneously hypertensive rats (SHR) with chronic inhibition of nitric oxide exhibit similar aortic stiffness to old SHR

The old spontaneously hypertensive rat (SHR) is known to be a good experimental model that is highly analogous to essential hypertension in man but is costly and time consuming. Chronic inhibition of nitric oxide (NO) production in young adult SHR is an experimental model of malignant hypertension and chronic renal disease, very similar to old SHR1. Considering that acute or chronic decreases in NO production in normotensive rats increase arterial stiffness, we aimed to compare the aortic stiffness between SHR/L-NAME and old SHR. Male SHR (18 weeks old) received N-Nitro-L-Arginine Methyl Ester (L-NAME) 6 mg/kg/d in drinking water (SHR/L-NAME) for 2 weeks and were compared to SHR and Wistar Kyoto rats (WKY). Moreover, two groups are composed of 55 weeks aged SHR (Old SHR) and WKY (Old WKY). Under anesthesia, two catheters were introduced in the left common carotid artery and the left femoral artery to measure central and peripheral blood pressure and assess aortic stiffness with pulse wave velocity (PWV= distance between the tips of the two catheters / transit time), β-index (2.11×(PWV2/Diastolic blood pressure)), amplification and pulse pressure (PP). At 20 weeks, although SHR have higher central systolic blood pressure (SBP) than WKY (201±7 mmHg vs. 154±4 mmHg), no significant difference in PWV, PP, amplification and β-index was observed between these two groups. With age, old WKY have higher SBP (181±8 mmHg) and higher PWV (6.7±0.5 m/s) and β-index (0.70±0.08) than young WKY. Old SHR exhibit higher SBP (252±13 mmHg), PWV (9.3±0.7 m/s), PP (71±7 mmHg), β-index (1.08±0.16) than old WKY and young SHR (PWV=6.3±0.2 m/s, PP=39±3 mmHg and β-index=0.50±0.03). Young SHR, after 2 weeks of L-NAME administration, have higher SBP (238±10 mmHg) and aortic stiffness (PWV=8.6±0.6 m/s, PP=54±6 mmHg and β-index=0.89±0.14) than young SHR and possess the aortic stiffness observed in old SHR. In conclusion, our results indicate a close analogy in arterial stiffness between SHR/L-NAME and old SHR. Thus, this experimental model shows similarities to hypertensive humans and appears relevant to test new anti-hypertensive treatments.

Myocardial and Aortic Stiffening in the Early Course of Primary Aldosteronism

Primary aldosteronism (PA) has been experimentally and clinically linked to myocardial and vascular fibrosis, and it has been further associated with left ventricular (LV) structural adaptations. Functional cardiovascular adaptations in hypertensive patients with PA precede structural alterations in the early stages of the disease. We studied 17 hypertensive subjects with a recent diagnosis of PA (10 male patients, aged approximately 55 y, with office blood pressure [BP] of 137/88 mm Hg), and 30 essential hypertensives matched for age, sex, office BP levels, treatment status, and LV mass index (LVMI). Apart from standard 2-Dimensional (2-D) and conventional Doppler parameters, tissue Doppler imaging (TDI) methodology was used to assess LV diastolic function; averaging early and late diastolic mitral annular peak velocities (Emav/, Amav, Emav/Amav ratio) from 4 separate sites of measurement (septal, lateral, anterior, and inferior walls). Aortic stiffness was evaluated by means of carotid-femoral pulse wave velocity (cf-PWV) measurements. Although transmitral E/A ratio was similar in both groups (0.95+/-0.26 versus 0.98+/-0.24, p=0.66), hypertensive subjects with PA compared with essential hypertensives are characterized by significantly higher relative wall thickness (0.50+/-0.07 versus 0.41+/-0.06, p<or=0.001), decreased values of Emav (7+/-1.7 versus 8.1+/-1.8 cm/s, p=0.048), and Emav/Amav ratio (0.63+/-0.16 versus 0.77+/-0.17, p=0.015). The higher PWV in the PA population failed to reach statistical significance (8.5+/-1.6 versus 7.9+/-0.9 msec, p=0.19). Our study demonstrates altered LV geometry and TDI-revealed diastolic dysfunction in hypertensives with PA compared with demographically- and LVMI-matched essential hypertensives. Furthermore, the increased aortic stiffening in PA patients failed to reach statistical significance.

From ‘optimal’ to ‘borderline’ blood pressure in subjects under chronic antihypertensive therapy

The ESH2003 report (J Hypertens 2003, 21:1011-1053) has classified brachial blood pressure into six groups reflecting the consistently increasing cardiovascular risk caused by high blood pressure. Chronically treated hypertensive individuals with well-controlled blood pressure retain higher cardiovascular risk than normotensive untreated individuals. Differences between these groups in arterial stiffness, pressure wave reflections and central blood pressure, which are all predictors of cardiovascular risk independently of peripheral blood pressure, have never been studied. A cohort of 216 treated subjects with controlled hypertension was compared with 105 never-treated normotensive controls, according to the ESH2003 blood pressure groups. Aortic stiffness (pulse wave velocity; PWV), carotid wave reflections (augmentation index; AI) and carotid pressures were measured non-invasively, by pulse wave analysis. Systolic blood pressure (SBP) and pulse pressure (PP) amplification between brachial and carotid arteries were estimated. The distribution of subjects in each subgroup of the untreated and treated populations was: 'optimal', 21 versus 43; 'normal', 44 versus 77; 'borderline', 40 versus 96. Brachial blood pressure, carotid SBP and PP did not differ between the two populations, but a constant interaction between blood pressure classification and treatment effect on PWV, AI and blood pressure amplification was found. Compared with untreated subjects, treated subjects had higher AI and lower blood pressure amplification (in the optimal group) and higher PWV (in the borderline group). 'Optimal' to 'borderline' blood pressure control in chronically treated hypertensive individuals is associated with impaired properties of the large and small arteries. These results suggest that antihypertensive treatment strategies with more beneficial effects on arterial properties are needed.

Association between glycosylated hemoglobin, left ventricular mass and aortic function in nondiabetic individuals with insulin resistance

An association between glycosylated hemoglobin (GHb) and cardiovascular mortality in nondiabetic individuals has recently been reported. Prompt detection of nondiabetic individuals with high-normal GHb and early cardiovascular involvement may be of value for preventive strategies. In this investigation, a possible relationship between GHb, aortic function and left ventricular (LV) mass in nondiabetic individuals has been studied. A total of 263 nondiabetic African-Americans, aged 22-63 (mean 42 +/- 8) years were studied. All individuals were first degree relatives of diabetic patients, had normal oral glucose tolerance test (2-h OGTT) and decreased peripheral action of insulin. LV diameters and mass (echocardiography); ascending and abdominal aortic distensibility (echocardiography, arterial pressure); pulse wave velocity (PWV; electrocardiography, Doppler); fasting glucose; GHb; insulin sensitivity index (S(I)) and 2-h OGTT were measured. Multiple linear and logistic regression analyses were used to identify significant independent associations of fasting glucose; GHb; S(I) and 2-h OGTT with aortic function and LV mass. In fully adjusted multivariate logistic regression analysis, GHb predicted lower values of aortic distensibility (odds ratio (OR) 1.67 95% CI (1.04-2.75), P=0.04); higher PWV (OR 1.79 95% CI (1.09-2.93), P=0.022); and higher values of LV mass (OR 1.56 95% CI (1.08-2.88), P=0.029). Fasting glucose, S(I), and 2 h OGTT were not associated with aortic function and LV mass. Higher GHb concentrations, even within 'normal' range, are independently associated with stiffer aorta and increased LV mass and thus may detect nondiabetic individuals at increased cardiovascular risk.

Bone mineral density and vascular calcification

It is of interest that in the general population, low bone mass is associated with a higher mortality rate due to atherosclerotic cardiovascular disease. In addition, the degree of aortic calcification is closely related with a lower bone mineral density (BMD). These results suggest that a low BMD may predict increased arterial stiffness. In ESRD patients, advanced arterial stiffness and low BMD due to renal osteodystrophy are not uncommon. Moreover, the initiation and progression of arterial stiffness and bone loss are accelerated by the same factors such as hyperphosphatemia secondary to chronic renal failure. A lower BMD might be more clearly associated with a higher PWV in dialysis patients than in the general population. To prove this hypothesis, we performed a preliminary cross-sectional study to investigate the relationship between BMD, as determined by calcaneal osteo-sono index (OSI), and arterial stiffness, as measured by the brachial-ankle PWV (baPWV). Our study demonstrated that calcaneal OSI, a marker for estimated BMD, has a powerful predictor of arterial stiffness, independent of classic risk factors, malnutrition, or inflammation markers. The evaluation of BMD needs to grasp not only the status of bone disease, but also the degree of arterial stiffness.

Arterial distensibility in children and teenagers: normal evolution and the effect of childhood vasculitis

Background: Polyarteritis nodosa is a necrotising vasculitis of the medium sized and small muscular arteries. The inflammatory and subsequent reparative processes may alter the arterial mechanical properties. The effect of...