Aortic Stiffness Index Beta Research Articles

Evaluation of arterial stiffness between peritoneal dialysis and hemodialysis in patients with renal replacement therapy

Objectives: The aortic stiffness index beta (ASI-β), calculated noninvasively with the pressure change caused by arterial strain and volume changes on echocardiography, shows a strong correlation with invasive measurements of arterial stiffness. This study aimed to compare arterial stiffness and distensibility between peritoneal dialysis (PD) and hemodialysis (HD) and patients in renal replacement therapy. Methods: This cross-sectional and observational study analyzed 108 patients under renal replacement therapy (PD and HD). The aortic stiffness index beta (ASI-β) was calculated for each group. Results: The mean age of the patients in the study was 58.2±11.1 years, and 49 (45.4%) of the patients were female and 59 (54.6%) were male. Age, gender, comorbid rates, and levels of blood pressure and heart rate did not differ between the PD and HD groups. Blood pressure levels and heart rate. Mean aortic strain (5.6±1.9 vs. 9.4±2.8, p < 0.001) and median distensibility (1.5 vs. 2.9 cm, p < 0.001) were lower in the PD group than the HD group, while median ASI-β (11.6 vs. 6.2, p < 0.001) and mean E/e’ (10.6±2.9 vs. 9.2±2.3, p = 0.006) were higher in the PD group. The rate of concentric hypertrophy was higher in the PD group (47.5% vs. 23.5%, p = 0.005). Conclusion: PD patients have higher arterial stiffness and lower distensibility levels compared to HD patients. Therefore, patients with PD may be more prone to diastolic dysfunction, cardiovascular disease, and events.

Vascular inflammation and aortic stiffness relate to early left ventricular diastolic dysfunction in prehypertension

Prehypertension is characterized by an increased cardiovascular risk and by an increased prevalence of target organ damage compared with the pure normotensive state. The present study was designed to assess in prehypertensive subjects the possible relationships between early left ventricular dysfunction, vascular inflammation and aortic stiffness. The study population consisted of 31 untreated prehypertensive subjects (age: 34 ± 6 years, mean ± SD) and 31 age-matched pure normotensive controls. Left ventricular function was assessed by echocardiography, aortic distensibility parameters were derived from aortic diameters measured by ultrasonography, and high-sensitivity C-reactive protein was assessed by latex-enhanced reagent. Prehypertensive subjects displayed a significantly lower E/A ratio and a significantly greater deceleration time and isovolumetric relaxation time compared with normotensive controls. They also displayed aortic systolic diameter, diastolic diameter and mean aortic stiffness index beta significantly increased while systo-diastolic diameter change, mean aortic distensibility and aortic strain were significantly reduced compared with controls. Values of inflammatory markers were increased. At multiple regression analysis, E/A ratio was significantly related to high-sensitivity C-reactive protein and aortic stiffness index beta, after correction for age, left ventricular mass index and mean blood pressure (β coefficient = −0.49, overall r2 = 0.24, p = 0.01 and β coefficient =−0.46, overall r2 = 0.21, p = 0.02, respectively). Thus, in prehypertension, left ventricular dysfunction is significantly related to vascular inflammation and aortic stiffness, suggesting that early cardiac and vascular alterations may have an increased inflammatory process as a common pathophysiological link.

Impact of Arterial Stiffness on Adverse Cardiovascular Outcomes and Mortality in Peritoneal Dialysis Patients

Cardiovascular (CV) disease is a major cause of morbidity and mortality in patients with end-stage renal disease. In recent years, arterial stiffness has taken on great importance in the pathophysiology of CV diseases. The independent predictive value of arterial stiffness for CV events and for all-cause and CV mortality has been demonstrated in the general population and in hemodialysis patients. Our aim in this study was to determine the relationship of arterial stiffness with mortality and fatal and nonfatal CV events in peritoneal dialysis (PD) patients. In this prospective observational cohort study with 2 years of follow-up, we studied a cohort of 156 PD patients with a mean follow-up of 19.2 ± 6.4 months. At baseline, echocardiography and standard clinical and biochemical analyses were performed in all patients and in 28 healthy subjects. Aortic stiffness index beta (ASIβ, a surrogate marker of arterial stiffness) was calculated as follows: ASIβ = ln (systolic blood pressure / diastolic blood pressure) / [(systolic diameter – diastolic diameter) / diastolic diameter]. During the follow-up period, 25 of the patients (16.0%) died, and 10 of those deaths had CV causes. Nonfatal CV events occurred in 15 patients. The median ASIβ was greater in PD patients than in control subjects (4.2 vs. 3.5; interquartile range: 3.2 - 5.5 vs. 2.5 - 4.8; p = 0.028]. In the fully adjusted multivariate Cox regression analysis (co-variates: age, sex, albumin, hemoglobin, diabetes mellitus, comorbid CV disease, left ventricular mass index, residual glomerular filtration rate, dialysate-to-plasma ratio of creatinine, Kt/V urea, left ventricular ejection fraction, duration of dialysis, smoking), ASIβ independently predicted fatal and nonfatal CV events (hazard ratio: 1.239; 95% confidence interval: 1.103 to 1.392), but not all-cause mortality. Our results provide the first direct evidence that arterial stiffness is an independent risk predictor of adverse CV outcome in PD patients.

The Relationship of Gamma-Glutamyltransferase to Aortic Elastic Properties in Young Patients with Prehypertension

Some cross-sectional studies have demonstrated a positive association between serum gamma-glutamyltransferase (GGT) levels and blood pressure. Accordingly, we aimed to analyze serum GGT levels in patients with prehypertension and examine the relationship with aortic elasticity parameters. The study population consisted of 25 newly diagnosed prehypertensive individuals and 25 healthy control subjects. Aortic strain, distensibility index, and stiffness index beta were calculated from aortic diameters measured by echocardiography and blood pressures simultaneously measured by sphygmomanometry. Prehypertensive patients were detected to have significantly lower aortic distensibility and strain indexes compared to control subjects aortic distensibility. However, aortic stiffness index beta of the prehypertensive group was significantly higher compared to that of the control group (3.73 ± 1.41 vs. 2.97 ± 0.82, p = 0.02). The mean GGT levels were found to be higher in patients with prehypertension compared to those of controls (47.9 ± 15.9 U/L vs. 36.1 ± 9.4 U/L, p = 0.003). When multiple linear regression analysis was done to clarify the contributions of GGT to aortic elasticity adjusting for age, body mass index, uric acid, serum glucose, heart rate, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, and triglyceride, we observed that only serum GGT levels were significantly associated with aortic elasticity parameters (for aortic strain beta = −0.247, p < 0.001; for aortic distensibility beta = −0.108, p < 0.001; for stiffness index beta = 0.063, p < 0.001). Whatever the mechanism is, young patients with prehypertension have higher serum GGT levels compared to healthy control subjects. More importantly, increased GGT levels are independently associated with impaired aortic elasticity in patients with prehypertension.

Associations Between Augmentation Index and Severity of Atheroma or Aortic Stiffness of the Descending Thoracic Aorta by Transesophageal Echocardiography

Although the aortic augmentation index (AI) is an attractive tool as an index of the vascular system, the association between radial AI or brachial-ankle pulse wave velocity (PWV) and severity of atheroma or arterial stiffness of the morphological central artery is unclear. Severity of atheroma and aortic stiffness of the descending thoracic aorta (DTA) by transesophageal echography in 96 patients with paroxysmal atrial fibrillation was assessed. The relationship between radial AI or brachial-ankle PWV and atherosclerotic lesions was also investigated. The DTA was divided into 3 equal longitudinal portions, and the atheromatous lesions of each portion of the DTA were scored according to their character and extension. Instantaneous dimensional changes in the DTA was measured, and the aortic stiffness index beta was calculated. Radial AI was significantly correlated with age, plasma low-density lipoprotein-cholesterol concentrations, systolic blood pressure, pulse pressure, the mean atheromatous score and the mean aortic stiffness index. However, brachial-ankle PWV was not associated with central arterial stiffness. Multivariate logistic regression analysis showed that radial AI was most closely correlated with the mean atheromatous score. Radial AI might be a novel tool for determining the severity of central aortic atheromatous lesions.

Impaired aortic elastic properties in young patients with prehypertension

Although hypertension has been shown to be one of the most important predictors of reduced arterial elasticity, there is not enough data about aortic elastic properties in patients with prehypertension. Accordingly, the current study was designated to evaluate aortic elastic features in young patients with prehypertension. The study population consisted of 25 newly diagnosed prehypertensive individuals (18 men, mean age=34+/-6 years) and 25 healthy controls (16 men, mean age=33+/-6 years) eligible for the current study. Aortic strain, distensibility index and stiffness index beta were calculated from aortic diameters measured by echocardiography and blood pressures simultaneously measured by sphygmomanometry. Prehypertensive patients were detected to have significantly lower aortic distensibility and strain indexes than the controls: (5.77+/-1.91 vs. 8.63+/-2.67 cm dynx10, respectively, P<0.001; strain index: 13.81+/-4.50 vs. 17.47+/-4.25%, respectively, P=0.005). Aortic stiffness index beta of the prehypertensive group, however, was significantly higher than that of the control group (3.73+/-1.41 vs. 2.97+/-0.82, P=0.02). Whatever the mechanism, young patients with prehypertension have impaired aortic elasticity compared with healthy controls. This finding has suggested that the development of overt hypertension may be prevented or delayed by using the agents that have the ability to reduce arterial stiffness by regressing and/or preventing functional and structural changes on the arterial wall.