Augmentation Index

Some 10% to 15% of hypertensive patients have hyperaldosteronism, an increased ambulant aldosterone-to-renin ratio. As aldosterone reduces arterial compliance, we examined the relationship between aldosterone-to-renin ratio, aortic blood pressure (BP), arterial stiffness, and the effect of spironolactone in a hypertensive population. In 24 untreated patients (mean age 51 +/- 2 years, 10 women), we assessed arterial stiffness by augmentation index-height of the late systolic peak in the aorta, pulse pressure (Sphygmocor), and aortic pulse wave velocity (Complior). There were significant positive correlations between the aldosterone-to-renin ratio and aortic systolic pressure, aortic pulse pressure, and augmentation index and negative correlations with pulse pressure amplification, but none with brachial BP or pulse wave velocity. After randomization in a cross-over design to 50 mg of spironolactone or 2.5 mg of bendroflumetazide for 4 weeks with washout period of 1 month, both drugs ...

Wave reflections affect the proximal aortic pressure and flow waves and play a role in systolic hypertension. A measure of wave reflection, receiving much attention, is the augmentation index (AI), the ratio of the secondary rise in pressure and pulse pressure. AI can be limiting, because it depends not only on the magnitude of wave reflection but also on wave shapes and timing of incident and reflected waves. More accurate measures are obtainable after separation of pressure in its forward (P f ) and reflected (P b ) components. However, this calculation requires measurement of aortic flow. We explore the possibility of replacing the unknown flow by a triangular wave, with duration equal to ejection time, and peak flow at the inflection point of pressure (F tIP ) and, for a second analysis, at 30% of ejection time (F t30 ). Wave form analysis gave forward and backward pressure waves. Reflection magnitude (RM) and reflection index (RI) were defined as RM=P b /P f and RI=P b /(P f +P...

Abstract: In the process of the WTO accession Ukraine has to liberalize both its tariff and non-tariff trade regimes. However, while tariffs have been studied more or less deeply, the country's system of non-tariff barriers remains almost terra incognita both for scientists and ...

The aim of the current investigation was to test the hypothesis that age-related changes in augmentation index (AIx) are more prominent in younger individuals (<50 years), whereas changes in aortic stiffness per se are more marked in older individuals (>50 years).Aging exerts a number of deleterious changes in the cardiovascular system, and, in particular, on the large arteries. Previous studies have suggested that AIx and pulse wave velocity (PWV) increase linearly with age, yet epidemiological data concerning pulse pressure suggest that large artery stiffening predominantly occurs later in life.Peripheral and central blood pressure, augmentation pressure (AP), and AIx were determined in 4,001 healthy, normotensive individuals, aged 18 to 90 years. Aortic and brachial PWV were also determined in a subset of 998 subjects.Peripheral and central pulse pressure, AP, AIx, and aortic and brachial PWV all increased significantly with age; however, the age-related changes in AIx and aortic PWV were non-linear, with AIx increasing more in younger individuals, whereas the changes in PWV were more prominent in older individuals.These data suggest that AIx might be a more sensitive marker of arterial stiffening and risk in younger individuals but aortic PWV is likely to be a better measure in older individuals.

ObjectiveTo assess endothelial function in normal pregnancy by non-invasive methods.To assess endothelial function in normal pregnancy by non-invasive methods.MethodsFlow-mediated dilatation of the brachial artery was measured by ultrasonography in 157 women with normal singleton pregnancies between 10 and 40 weeks' gestation and 19 non-pregnant controls.ResultsFlow-mediated dilatation in the non-pregnant controls was 6.42 ± 2.45%. In pregnant women, between 10 and 30 weeks, the mean flow-mediated dilatation (8.84 ± 3.18%) was significantly higher than the non-pregnant controls (P = 0.002), but after 30 weeks of gestation there was a decrease to prepregnancy levels. Resting vessel diameter and blood flow were significantly increased in pregnancy, mainly after 30 weeks' gestation (P < 0.001, P < 0.001, respectively). Flow-mediated dilatation was significantly correlated to resting vessel diameter and reactive hyperemia.Flow-mediated dilatation of the brachial artery was measured by ultrasonography in 157 women with normal singleton pregnancies between 10 and 40 weeks' gestation and 19 non-pregnant controls.ResultsFlow-mediated dilatation in the non-pregnant controls was 6.42 ± 2.45%. In pregnant women, between 10 and 30 weeks, the mean flow-mediated dilatation (8.84 ± 3.18%) was significantly higher than the non-pregnant controls (P = 0.002), but after 30 weeks of gestation there was a decrease to prepregnancy levels. Resting vessel diameter and blood flow were significantly increased in pregnancy, mainly after 30 weeks' gestation (P < 0.001, P < 0.001, respectively). Flow-mediated dilatation was significantly correlated to resting vessel diameter and reactive hyperemia.ConclusionNormal pregnancy is associated with enhanced endothelial function which is apparent from at least 10 weeks' gestation. Copyright © 2000 International Society of Ultrasound in Obstetrics and GynecologyNormal pregnancy is associated with enhanced endothelial function which is apparent from at least 10 weeks' gestation. Copyright © 2000 International Society of Ultrasound in Obstetrics and Gynecology

Various factors are implicated in the circadian pattern of cardiovascular vulnerability. The exact mechanisms involved in the peak incidence of cardiovascular events occurring during the early morning hours after awaking are not completely known. The purpose of our study was to investigate the circadian variation of timing and intensity of wave reflections in healthy individuals and to test the hypothesis that significant changes occur during the day. Thirteen healthy non-smokers (seven women and six men, mean age 40.7 +/- 16.5 years) were examined. Aortic pulse wave analysis was performed to estimate surrogates of wave reflections intensity (augmentation index [AIx]) and timing. Twelve measurements separated by 1-h intervals were performed from 8 am to 7 pm each study day. Analysis of variance for repeated measures indicated significant changes during the 12-h period for heart rate corrected AIx (P = .033) and heart rate (P = .035). The AIx was maximal at 8 am within 1-h after awak...

We investigated the effects of violet laser acupuncture on arterial stiffness and other important parameters of the functional state of the heart such as augmentation index (AIx). This investigation ties together the medical perspectives of Eastern and Western medical practitioners; the Western medical perspective of the functional states of the human heart including systolic and diastolic blood pressures, and the Eastern medical perspective regarding taking patients&#x27; pulses for diagnosis and using acupuncture for subsequent treatments. Pulse wave velocity (PWV) is a direct marker of arterial stiffness; AIx indicates wave reflection. Both parameters can be measured by cuff applied to the brachial artery. The first results from a pilot study of 10 healthy volunteers (M/F, 3/7; mean age ± SD, 27.8 ± 6.8 years) regarding violet laser acupuncture (405 nm; 110 mW; 500 μm; 10 min) showed a marked but not statistically significant decrease in aortic PWV and an increase in brachial AIx...

Aortic pulse wave velocity (PWV) and augmentation index are independent predictors of adverse cardiovascular events, including mortality. In hypertension and aging, central elastic arteries become stiffer, diastolic pressure decreases, and central systolic and pulse pressures are augmented due to increased PWV and early return of reflected waves to the heart from the periphery. Valuable information on arterial properties such as stiffness can be obtained from both central (aortic) and peripheral (radial artery) pressure waveforms, but absolute values of wave reflection amplitude and wasted left ventricular (LV) pressure energy can only be obtained from the central arterial pressure waveform. As the arterial system becomes stiffer, there is a marked increase in central systolic and pulse pressures and wasted LV energy, along with a decrease in pulse pressure amplification. The increase in aortic systolic and pulse pressures are due primarily to increases in PWV and wave reflection am...

Arterial stiffness is an important determinant of cardiovascular morbidity and mortality. The I/D polymorphism of angiotensin-converting enzyme (ACE) gene is associated with cardiovascular disease. However, the relationship between ACE polymorphism, arterial stiffness, and wave reflections in healthy, low-risk population has not been defined yet. The study included 282 apparently healthy, low-risk individuals (mean age 39.7 +/- 8.9 years, 178 males). Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness, while wave reflections were assessed by augmentation index (AIx) of the central pressure waveform. I/D polymorphism of the ACE gene was determined in all subjects for the prevalence of the DD, ID, and II genotype (39, 44, and 17%, respectively). C-reactive protein (CRP) levels were determined as a marker of chronic, subclinical inflammation. After adjustment for potential confounding factors, presence of D allele was associated with lower values of P...

The effect of coffee consumption on the cardiovascular system is still an unresolved issue. Aortic stiffness and wave reflections are important prognosticators of cardiovascular disease risk. We have shown that caffeine acutely increases aortic stiffness and wave reflections. The objective was to investigate the effect of chronic coffee consumption on aortic stiffness and wave reflections. This was a cross-sectional study of 228 healthy subjects: 141 men (x +/- SD: 41 +/- 8 y old) and 87 women (41 +/- 9 y old). Aortic stiffness was evaluated with carotid-femoral pulse wave velocity (PWV). Wave reflections were evaluated with augmentation index (AIx) and augmented pressure (AP) of the aortic pressure waveform with the use of high-fidelity pulse wave analysis. Coffee consumption was ascertained over 1 y with a food-frequency questionnaire. A linear relation between coffee consumption and PWV, AIx, and AP was observed (P for trend &lt; 0.05). Compared with the nonconsumption group, PWV...

Wave reflection augments central blood pressure (BP) in late systole, thus increasing cardiac afterload. We examined the relationship between late systolic pressure augmentation in the peripheral radial artery pulse wave and the existence of left ventricular hypertrophy (LVH) in hypertension. Brachial BP, radial augmentation index (AI(r)), and carotid-femoral pulse wave velocity (PWV(cf)) were determined in 77 untreated hypertensive patients aged 56 +/- 10 years. Cardiac structure and function were assessed by ultrasound, and LVH was defined based on the LV mass index (LVMI). Using multivariate analysis, patient characteristics were compared between those with (+) and without (-) LVH. The LVMI was correlated independently and positively with AI(r) (beta = 0.33, P = .004) and the brachial mean arterial pressure (MAP; beta = 0.25, P = .03). The ratio of early to atrial peak velocities (E/A ratio) of the diastolic transmitral flow tended to be correlated negatively with the AI(r). The ...

Pulse wave analysis (PWA) combined with β2-agonist challenge has recently been used to assess endothelial function. β-2 adrenergic receptor (β2AR) polymorphisms may affect response to β2-agonist. We determined whether β2AR polymorphisms influence endothelial response in our model using PWA and salbutamol.388 healthy Malay subjects (177 males, 211 females) were genotyped for 5 functionally important single nucleotide polymorphisms (SNPs) of β2AR; 298 subjects proceeded with assessment of endothelial function. The parameter augmentation index (AIx) was recorded non-invasively using SphygmoCor. Recording of AIx at baseline was followed by administration of 500 µg sublingual glyceryl trinitrate (GTN). AIx recordings were repeated at 3, 5, 10, 15 and 20 min post-GTN. Subjects then inhaled 400 µg of salbutamol before AIx recordings at 5 min intervals up to 20 min. Maximum changes in AIx after GTN and salbutamol represented endothelium independent and endothelium dependent vasodilatation (EDV) respectively.Allele frequencies of mutated Gly16, Glu27, Ile164, − 20C and − 47C were 47%, 6.8%, 0%, 30% and 9.3% respectively. No significant differences in EDV were noted between genotype groups of each studied SNPs.Assessment of endothelial function using PWA and salbutamol was not influenced by β2AR polymorphisms.

Chronic heart failure (HF) is associated with increased central arterial pulse-wave reflections, which may contribute to increased myocardial oxygen demand. Although the treatment of HF via left-ventricular assist device (LVAD) placement has recently become widespread, the effects of LVAD therapy on central arterial pulse-wave reflections are unknown. Central aortic pulse-wave analysis was performed on patients with end-stage HF awaiting cardiac transplantation and on healthy age-matched controls using the SphygmoCor (Akor Medical, Sydney, Australia) system. Arterial pulse-wave data were compared between patients receiving LVAD support versus those receiving intravenous inotropic drugs and healthy control patients. Five patients on LVAD support were compared with 10 patients on inotropic drugs and 10 healthy control patients. Aortic augmented pressure and the aortic augmentation index (AI(a)) were higher in LVAD patients compared with inotrope and control patients, despite similar b...