Effects of nifedipine on mechanical properties of the normal and atherosclerotic descending aorta assessed by transesophageal echocardiography

The combination of IMT and stiffness parameter beta is highly associated with concurrent coronary artery disease in type 2 diabetes

AIMS

The clinical implications of stiffness of the carotid artery (CA) have not been fully clarified in the prediction of coronary artery disease (CAD), although intima-media thickness (IMT) has been established as a surrogate marker. We examined the associations of stiffness parameter beta (ST) and IMT with concurrent CAD.

METHODS

IMT and ST were measured by ultrasound in 439 nondiabetic subjects as a control and 1528 type 2 diabetic subjects (T2DM) with or without CAD in a cross-sectional study.

RESULTS

Both IMT and ST significantly increased with age and group category, in the order of control, T2DM without CAD, and T2DM with CAD (p<0.001). The area under the curve on ROC analysis of ST for concurrent CAD was comparable to that for IMT. On multivariate logistic regression analysis, High IMT (>or=1.30 mm) and High stiffness (>or=20.0) had significant odds ratios for concurrent CAD (2.205, p<0.001 and 1.548, p<0.05, respectively). The group with High IMT and High Stiffness exhibited a stronger multivariate odds ratio (3.115, p=0.0001).

CONCLUSIONS

ST and IMT are associated with CAD and exhibited significant odds ratios for CAD. Our findings suggest that the combination of IMT and ST is a useful marker of atherosclerosis.

Temocapril, an Angiotensin converting enzyme inhibitor, ameliorates age-related increase in carotid arterial stiffness in normotensive subjects

BACKGROUND/AIMS

Oxidative stress plays an important role in vascular ageing. The close relationship of the renin-angiotensin system with mechanisms of oxidative stress suggests its possible involvement in the deleterious effects of ageing. The present study was designed to investigate whether inhibition of the renin-angiotensin system improves the age-related increase in arterial stiffness.

METHODS

Normotensive elderly subjects in a geriatric nursing home (n = 24; male/female = 7/17; 86 +/- 9 years, mean +/- SD) were randomly assigned to receive either an angiotensin converting enzyme inhibitor, temocapril (n = 12, 1 mg daily) or nothing (n = 12). Carot id arterial stiffness parameter beta and circulating levels of malondialdehyde-modified low-density lipoprotein were measured before and 6 months after randomization.

RESULTS

Temocapril decreased beta (from 7.0 +/- 1.0 to 4.9 +/- 0.9, p < 0.05) and malondialdehyde-modified low-density lipoprotein levels (from 73.2 +/- 19.9 to 61.3 +/- 18.4 U/l, p < 0.05) without changing the blood pressure. The changes in beta and malondialdehyde-modified low-density lipoprotein levels were significantly correlated (rho = 0.600, p < 0.05).

CONCLUSION

These results suggest that temocapril ameliorates the age-related increase in carotid arterial stiffness in healthy, normotensive elderly subjects.

Impact of aortic stiffness on ischemic stroke in elderly patients

BACKGROUND AND PURPOSE

Large atherosclerotic plaques in the aortic arch detected by transesophageal echocardiography (TEE) are associated with increased risk of ischemic stroke in the elderly. The atherosclerotic process also affects aortic distensibility, which can also be assessed by TEE. The purpose of this study was to evaluate the possible association of aortic stiffness by TEE with ischemic stroke in elderly patients.

METHODS

We performed TEE in 40 consecutive elderly patients aged > or =55 years with acute ischemic stroke and in 42 consecutive control subjects aged > or =55 years. Aortic stiffness index beta, which has been used in the literature to express the stiffness of the aortic wall, was calculated as follows: beta=ln (systolic blood pressure/diastolic blood pressure)/([D(max)-D(min)]/D(min)), where ln is natural logarithm, D(max) is maximum aortic lumen diameter, and D(min) is minimum aortic lumen diameter by TEE. The association of index beta with ischemic stroke was evaluated by logistic regression analysis after adjustment for potential confounders, including thickness of aortic arch plaques.

RESULTS

Index beta was significantly greater in stroke patients than in controls (9.7+/-5.0 versus 5.3+/-3.5; P<0.0001). When aortic plaque thickness and other stroke risk factors were entered in multivariate analysis, index beta was found to be independently associated with ischemic stroke (odds ratio, 1.28 per unit increase; 95% CI, 1.10 to 1.52).

CONCLUSIONS

Aortic stiffness by TEE is associated with ischemic stroke, independent of thickness of aortic arch plaques and other stroke risk factors. This suggests that aortic stiffness by TEE may add prognostic information when assessing the risk of ischemic stroke in the elderly.

Effect of olprinone, a phosphodiesterase III inhibitor, on arterial wall distensibility: differentiation between aorta and common carotid artery

Although the effects of phosphodiesterase III (PDE III) inhibitors as vasorelaxants have been well documented, there are only few data on the wall response of different arteries. We evaluated the artery-specific effect of olprinone (OP), one of the PDE III inhibitors, on the major branches of human arteries and peripheral circulation. In 14 healthy subjects (average age: 57.5 +/- 21.2 years), systolic and diastolic diameters (Ds and Dd, respectively) and the time velocity integral (VI) of flow velocity patterns were measured by M-mode and Doppler echocardiography in the carotid artery (CA), the ascending aorta (asAo), the abdominal aorta (abAo), and the left ventricular outflow tract. Blood pressure (BP) was simultaneously measured using a cuff sphygmomanometer. Measurements were taken before and 20min after a bolus injection of OP (0.2 microg/kg). Distensibility (Ds - Dd), stiffness parameter beta (In(systolic BP/diastolic BP)/(Ds/Dd - 1)), cardiac output (CO: (Flow Area) x VI x HR at left ventricular outflow), selective flow volume (FV: (Flow Area) x VI x HR at CA or abAo), and vascular resistance (VR: mean BP/(CO or FV)) were then calculated. The distensibility increased significantly after OP administration (P = 0.0015), but that of the asAo or abAo did not change. Although there was a significant increase in CO (P = 0.001) and a significant decrease in systemic VR (P = 0.001) following OP administration, the FV and VR of both CA and abAo did not change significantly. The selectiveness of the effect of OP was demonstrated in terms of the CA wall distensibility. This was thought to be attributable to the differences in the structural components or the reactivity of smooth muscle cells to OP.

Transesophageal echocardiography in the diagnosis of diseases of the thoracic aorta: part II-atherosclerotic and traumatic diseases of the aorta

Transesophageal echocardiography (TEE) has provided an accurate new window for the evaluation of diseases of the thoracic aorta. Experience with TEE has led to an increased recognition of atherosclerosis of the thoracic aorta as a source of cerebral and systemic embolism. Certain features of aortic plaque morphology detected by TEE may prove to have prognostic and therapeutic significance. The intraoperative assessment of thoracic aortic atherosclerosis by TEE may guide modifications in surgical techniques and aortic manipulations that reduce the incidence of perioperative neurologic complications. TEE has also become a valuable tool for the diagnostic evaluation of patients with blunt chest trauma. The precise role of TEE in the management of these disorders is currently under investigation.

Assessment by transesophageal echography of atherosclerosis of the descending thoracic aorta in patients with hypercholesterolemia

This study assesses atheromatous lesions and aortic stiffness of the descending thoracic aorta (DTA) in patients with hyperlipidemia by transesophageal echography (TEE) and investigates the relations between atherosclerotic lesions and aging or serum cholesterol levels in these patients. Subjects included 16 patients with familial hypercholesterolemia (FH), 15 non-FH hyperlipidemic patients (non-FH), and 17 age-matched normal subjects. With use of TEE, the DTA was divided into 4 longitudinal portions of equal length, and the atheromatous lesions of each portion of DTA were scored according to their character and extension by biplane 2-dimensional TEE. The scores of atheromatous lesions from all 4 portions were added together to give the total atheromatous score. Then, after measuring the instantaneous dimensional changes of DTA in a cardiac cycle by M-mode TEE and blood pressure (BP) by a cuff method, we calculated the aortic stiffness parameter beta = ln(systolic BP/diastolic BP)/([Dmaximum - Dminimum]/Dminimum). The beta was significantly higher in FH and non-FH subjects than in normal subjects. In both FH and non-FH subjects, the total atheromatous score correlated with total serum cholesterol levels (r = 0.64 [p <0.01]; r = 0.58 [p <0.05], respectively). There were significant correlations between age and beta in all 3 groups (FH, r = 0.67 [p <0.005]; non-FH, r = 0.53 [p <0.05]; normal subjects, r = 0.49 [p <0.05]), and the slopes of the regression lines of FH and non-FH subjects were much steeper than those of normal subjects. The incidence of atherosis in the DTA was significantly higher in hyperlipidemic patients than in normal subjects, even among the younger members of the hyperlipidemic population with progressive aortic stiffness.

Echographical assessment of the early stage of experimental atherosclerosis of the descending aorta in rabbits

To assess the early stage of atherosclerosis of the thoracic descending aorta, we evaluated morphological atheromatous lesions (atherosis) and the stiffness parameter of the artery (beta; sclerosis) in 24 male rabbits using echography. Male Japanese white rabbits weighing 2.5-3.0 kg were fed a diet containing 1% cholesterol for 7 (n = 8) or 14 weeks (n = 8). Rabbits fed a normal diet were used as controls (n = 8). Atheromatous lesions were evaluated with intravascular ultrasound (IVUS: Aloka, 20 MHz, 6F). We also calculated beta using M-mode echography (7.5 or 10 MHz) and direct aortic pressure measurement. Thickening of the intima-media complex was clearly observed with IVUS in the 14-week group but was not detected in the others. Histologically, only a thin layer of foamy cells on the intima (thickness < 20 microns) was observed in the 7-week group. The value of beta was significantly increased in both the 7-week (4.7 +/- 2.2) and 14-week groups (4.5 +/- 0.8) compared with controls (1.7 +/- 0.9, both p < 0.01). These results suggest that the development of atherosis might be preceded by vascular sclerosis during the early stage of atherosclerosis when the serum cholesterol level is high: at a time when the thin layer of foamy cells could not be detected by conventional IVUS.

Increased stiffness of the aorta in children and adolescents with insulin-dependent diabetes mellitus

An ultrasonic system fitted with echo-tracking circuits was used to investigate the mechanical properties of the descending aorta in children and adolescents with insulin-dependent diabetes (IDDM). Seventy-six children and adolescents (aged 5-20 years) with uncomplicated diabetes and 75 age- and gender-matched healthy controls were examined. All subjects were normotensive. A nonlinear correlation between the stiffness index of the aorta and the age was found in both the diabetic (r = 0.47; P < 0.001) and control group (r = 0.57; P < 0.001). The stiffness index was higher among the diabetic subjects as compared to the controls (P < 0.01). No difference regarding stiffness of the aorta was found between genders in either of the groups. No correlation was observed between the stiffness index and the duration or degree of the metabolic control of diabetes. Our study demonstrated an increased stiffness of the aorta in children and adolescents with IDDM at the stage when no vascular complications were detected clinically.