Aortic distensibility abnormalities in coronary artery disease

Vasodilatory capacity of nonstenotic arteries in experimental animals with atherosclerosis is decreased. It was postulated that aortic distensibility may be abnormal in patients with coronary artery disease (CAD). Aortic distensibility was determined in 24 normotensive patients with CAD and an angiographically normal aorta and values were compared with those in 18 age-matched normal subjects. Aortic diameters were measured at 3 levels--2, 4 and 6 cm above the aortic valve--by angiographic techniques. The area of the first 6 cm of the aorta above the aortic valve was planimetered and mean aortic diameters were calculated. Distensibility was calculated using the formula: [2 X (changes of the aortic diameter)/(diastolic aortic diameter) X (changes of the aortic pressure)]. CAD patients had similar aortic pressures but markedly lower distensibility than normal subjects: 0.7 +/- 0.2 vs 1.7 +/- 0.3 (p less than 0.02); 1.5 +/- 0.3 vs 4.0 +/- 0.6 (p less than 0.02); and 1.2 +/- 0.2 vs 5.3 +/- 0.6 (p less than 0.001) at 2, 4 and 6 cm above the aortic valve, respectively. Distensibility was also calculated from the mean aortic diameters and was greater in normal subjects than in CAD patients (3.4 +/- 0.4 vs 1.6 +/- 0.1, p less than 0.001). Decreased aortic distensibility in CAD may be related to the common atherosclerotic process or to reduced ascending aorta vasa vasorum flow from coronary arteries.     

Increased aortic stiffness in patients with coronary artery ectasia

OBJECTIVE: Alterations in aortic stiffness may reflect the elastic properties of the larger arteries. In many diseases, aortic elastic properties have been investigated to show whether the larger arteries are involved. The elastic properties of aorta in patients with coronary artery ectasia, however, have not been studied yet. We aimed to investigate aortic stiffness parameters in patients with coronary artery ectasia and to compare patients with coronary artery ectasia and coronary artery disease with the control group. METHOD: Thirty-three patients with coronary artery ectasia, 31 patients with coronary artery disease and 30 patients with angiographically normal coronary arteries were included in this study. Aortic diameters were measured on the M-mode tracing obtained at a level 3 cm beyond the aortic valve at parasternal long-axis view. Aortic diameter change, aortic strain, aortic distensibility and stiffness parameters were measured as aortic stiffness parameters. RESULTS: Aortic diameter changes were fewer in the coronary artery ectasia and coronary artery disease group than in the control group (0.4 +/- 0.1 and 0.3 +/- 0.1 vs. 0.8 +/- 0.2; P < 0.001). Aortic distensibility and aortic strain were significantly lower in patients with coronary artery ectasia and coronary artery disease than in the controls (for aortic distensibility P < 0.001 and for aortic strain P < 0.001, < 0.001, respectively). In contrast, a significantly higher aortic stiffness index was observed in patients with coronary artery ectasia and coronary artery disease than in the control group (14.2+/-2.6 and 18.1 +/- 2.9 vs. 5.9 +/- 1.8; P < 0.001, respectively). CONCLUSIONS: The impairment in aortic elastic properties in patients with coronary artery ectasia indicates that this disease is a generalized disease rather than a localized disease of the coronary arteries.     

The effects of hormonal therapy on aortic stiffness and left ventricular diastolic function

OBJECTIVE: The main objective of this study is to investigate the effects of oestrogen replacement therapy (ERT) and hormone replacement therapy (HRT) on aortic stiffness and on the left ventricular diastolic function, including tissue Doppler. METHODS AND RESULTS: The two study groups were composed of 20 postmenopausal women having HRT and 22 postmenopausal women having ERT. Each group was evaluated for aortic elasticity properties and the left ventricular diastolic function at both the pre-treatment stage and after 12 weeks of hormonal therapy.There was a significant improvement in beta index (5.2+/- 2.5 vs. 3.2+/- 2.2, p = 0.001), distensibility (5.2+/-3.7 vs. 6.1 +/-4.1 cm2 x dyn(-1) x 10(-3), p = 0.036) and mitral E/Em ratio (7.44 +/- 3.25 vs. 5.75 +/- .2.34, p = 0.004) with ERT. HRT was observed to improve aortic elasticity properties (for strain 10.7+/-4.7 vs. 12.8 +/-7.6%, for beta index 4.9+/-2.1 vs. 3.39+/- 2.4 and for distensibility 4.6+/- 2.1 vs.5.69 +/-4.1 cm2 x dyn(-1) x 10(-3)) and the mitral E/Em ratio (7.61 +/- 3.31 vs.5.81 +/-2.31, p = 0.003). CONCLUSION: Both ERT and HRT have an improving effect on aortic elasticity properties, as well as on the diastolic function.     

Relationship between aortic stiffness and the development of coronary collateral in patients with coronary artery disease

Large artery stiffness is an independent predictor of cardiovascular mortality and a major determinant of pulse pressure. The stiff aorta may result in greater systolic, lower diastolic, and wider pulse pressures, which may decrease coronary artery perfusion. Shear stress has been implicated in the development of coronary collateral. Decreased coronary perfusion may reduce shear stress and thus collateral formation. The goal of this study was to assess the relationship between the development of coronary collateral and aortic stiffness in patients with coronary artery disease. In 106 patients with at least one coronary artery stenosis of 90% or greater, collateral vessels were assessed angiographically by the Rentrop grading (grade 0-3), establishing two groups: 50 patients with poor collateral vessels (Rentrop grade 0 or 1), and 56 patients with good collateral vessels (Rentrop grade 2 or 3). Internal aortic root diameters were measured at 3 cm above the aortic valve by use of two-dimensional guided M-mode transthoracic echocardiography, and arterial pressure was measured simultaneously at the brachial artery by sphygmomanometry. Two indexes of the aortic elastic properties were measured: aortic distensibility index was calculated by use of the formula: 2 x (systolic diameter - diastolic diameter)/(diastolic diameter) x (pulse pressure) in cm(- 2)dyn(-1)10(-6). The aortic stiffness index was calculated by: (systolic blood pressure/diastolic blood pressure)/pulsatile change in diameter/diastolic diameter. The aortic distensibility index and the aortic stiffness index were not significantly different between the patients with poor collateral vessels and those with good collateral vessels (5.1 +/-2.3 vs 5.7 +/-3.3 cm(-2)dyn( -1)10(-6), p = 0.31; 4.02 +/-2.3 vs 4.43 +/-3.7, p = 0.49, respectively). There were no significant differences regarding the aortic elastic properties between the patients with poor collateral vessels and those with good collateral vessels, suggesting that collateral formation is a complex phenomenon consisting of several distinct processes.     

The Marfan syndrome: abnormal aortic elastic properties

Aortic distensibility and aortic stiffness index were measured at the ascending aorta (3 cm above the aortic valve) and the mid-portion of the abdominal aorta from the changes in echocardiographic diameters and pulse pressure in 14 patients with the Marfan syndrome and 15 age- and gender-matched normal control subjects. The following formulas were used: 1) Aortic distensibility = 2(Changes in aortic diameter)/(Diastolic aortic diameter) (Pulse pressure); and 2) Aortic stiffness index = ln(Systolic blood pressure)/(Diastolic blood pressure)(Changes in aortic diameter)/Diastolic aortic diameter. Pulse wave velocity was also measured. Compared with normal subjects, patients with the Marfan syndrome had decreased aortic distensibility in the ascending and the abdominal aorta (2.9 +/- 1.3 vs. 5.6 +/- 1.4 cm2 dynes-1, p less than 0.001 and 4.5 +/- 2.1, vs. 7.7 +/- 2.5, cm2 dynes-1, p less than 0.001, respectively) and had an increased aortic stiffness index in the ascending and the abdominal aorta (10.9 +/- 5.6 vs. 5.9 +/- 2.2, p less than 0.005 and 7.1 +/- 3.1 vs. 3.9 +/- 1.2, p less than 0.005, respectively). Aortic diameters in the ascending aorta were larger in these patients than in normal subjects, but those in the abdominal aorta were similar in the two groups. Linear correlations for both aortic distensibility and stiffness index were found between the ascending and the abdominal aorta (r = 0.85 and 0.71, respectively). Pulse wave velocity was more rapid in the patients than in the normal subjects (11.6 +/- 2.5 vs. 9.5 +/- 1.4 m/s, respectively, p less than 0.01). Thus, aortic elastic properties are abnormal in patients with the Marfan syndrome irrespective of the aortic diameter, which suggests an intrinsic abnormality of the aortic arterial wall.     

Acute improvement of aortic mechanics following hemodialysis in patients with chronic renal failure

BACKGROUND: Evidence suggests that distensibility of the aorta is decreased in patients with end-stage renal failure, while the underlying mechanisms are unclear. HYPOTHESIS: The purpose of the study was to evaluate the distensibility of the aorta in patients at the end stage of chronic renal failure before and after hemodialysis (HD). METHODS: The diameter of the ascending aorta and distensibility were assessed in 48 patients on HD (31 men, 17 women, aged 45+/-14 years) and in 27 normal subjects (17 men, 10 women, aged 44+/-14 years). The diameter of the aorta was evaluated by M-mode in the parasternal long-axis view. RESULTS: Aortic distensibility was significantly lower in patients on HD before HD (1.9+/-0.7 cm(2) x dyn(-1) x 10(-6)) than in normal control subjects (3.8+/-1.0 cm(2) x dyn(-1) X 10(-6), p< 0.0001). After dialysis, it increased to 2.6+/-1.2 (p < 0.05 compared with baseline, p < 0.001 compared with controls). The change of aortic distensibility correlated with age (R(2) = 0.629 p < 0.001) and ultrafiltration volume (R(2) = 0.168, p < 0.01). CONCLUSIONS: Aortic distensibility in patients with end-stage renal disease is significantly lower than in normal subjects, and it is significantly improved after HD.     

Aortic stiffness in systemic sclerosis is increased independently of the extent of skin involvement

OBJECTIVE: To study the stiffness of large arteries in relation to the extent of skin and lung fibrosis, aortic distensibility was examined in patients with diffuse and limited systemic sclerosis (SSc). METHODS: Consecutive patients (55 with diffuse and 51 with limited SSc) without signs and symptoms of heart failure or a previous history of arterial hypertension underwent echocardiography and lung function tests. Aortic stiffness was determined non-invasively by aortic distensibility and aortic strain measurements in all patients and in 50 healthy subjects, matched for age and gender. RESULTS: Aortic distensibility in patients with either diffuse (2.03 +/- 0.26 x 10(-6) cm(2) dyn(-1)) or limited SSc (2.12 +/- 0.33) was similarly decreased compared with controls (2.49 +/- 0.36, P<0.001). Moreover, aortic strain was significantly reduced in both patient groups compared with controls, confirming that aortic stiffness is increased in SSc independently of the extent of skin involvement. Left ventricular performance was similar between patients and controls, while left ventricular mass and tricuspid systolic gradient were significantly increased in both SSc groups, the latter being associated with aortic stiffness in multivariate analysis. No association with serum levels of C-reactive protein or lung function abnormalities indicative of pulmonary fibrosis were found. CONCLUSIONS: Stiffness of the aorta is increased in patients with established SSc regardless of the extent of the inflammatory fibrotic process in the skin and lungs, suggesting that additional pathogenetic mechanisms contribute to the compromise of large arteries.     

Effects of angiotensin-converting enzyme polymorphism on aortic elastic parameters in athletes

BACKGROUND: Physiologic adaptations in an athlete's heart include increased left and right ventricular chamber size, left ventricular wall thickness and mass. Angiotensin-converting enzyme (ACE) is a key enzyme in angiotensin II production causing cardiac hypertrophy. The cloning of the ACE gene has made it possible to identify a deletion (D)-insertion (I) polymorphism that appears to affect the level of serum ACE activity. Therefore, the ACE genes, which have been shown to be polymorphic, could be candidate genes for large-artery stiffness. METHODS: 56 endurance athletes and 46 sedentary subjects were included in this study, and they underwent both complete echocardiographic examination, and analysis of ACE insertion (I) and deletion (D) allele frequencies in peripheral blood. The aortic diameter was recorded by M-mode echocardiography at a level 3 cm above the aortic valve. Aortic systolic diameter was measured at the time of full opening of the aortic valve, and diastolic diameter was measured at the peak of QRS. Aortic strain, stiffness index and distensibility were calculated. RESULTS: Left ventricular mass index and left ventricular ejection fraction were significantly higher in athletes than controls (p < 0.001). The aortic distensibility index and strain were significantly greater in athletes compared with controls (respectively: 5.8 +/- 2.7 vs. 4.7 +/- 1.8 cm(-2) dyn(-1) 10(-6), p = 0.017; 12.3 +/- 2.4 vs. 9.3 +/- 3.1, p < 0.001). The aortic stiffness index was significantly lower in athletes than in controls (4.8 +/- 1.9 vs. 6.1 +/- 2.1, p < 0.001). The aortic distensibility index and strain were statistically different in ACE DD vs. DI groups and DD vs. II groups of athletes. The aortic stiffness index was statistically different in ACE DD vs. II groups of athletes. Aortic parameters were similar according to ACE genotypes in controls. CONCLUSION: The results of this study indicate that aortic distensibility was increased by prolonged training in endurance athletes, particularly in those with the ACE II genotype. This effect represents an extracardiac adaptation to chronic prolonged training in athletes.     

Effect of obstructive sleep apnea on aortic elastic parameters: relationship to left ventricular mass and function.

BACKGROUND: Obstructive sleep apnea (OSA) syndrome has a critical association with cardiovascular mortality and morbidity. Aortic elastic parameters are important markers for left ventricular (LV) function and are deteriorated in cardiovascular disease. METHODS AND RESULTS: Aortic elastic parameters and LV functions and mass were investigated in 40 patients with OSA (apnea - hypopnea index (AHI) >or=5) (mean age 51.3 +/-9 years, 32 males) and 24 controls (AHI <5) (mean age 51.9+/-5.2 years, 19 males). All subjects underwent polysomnographic examination and recordings were obtained during sleep. They also underwent a complete echocardiographic examination and systolic and diastolic aortic measurements were noted from M-mode traces of the aortic root. There were no significant differences in the demographic data of the patients with OSA and the controls. Subjects with OSA demonstrated higher values of aortic stiffness (7.1+/-1.88 vs 6.42+/-1.56, p=0.0001), but lower distensibility (9.47+/-1.33 vs 11.8+/-3.36, p=0.0001) than the controls. LV ejection fraction was significantly lower in patients with OSA when compared with the control group (61.3+/-5.2% vs 65.9+/-8.4%, p=0.0001). LV diastolic parameters were also compared and were worse in the subjects with OSA than in the control subjects (mitral E/A: 0.91 +/-0.42 vs 1.35+/-0.66, p=0.001; Em/Am: 0.86+/-0.54 vs 1.23+/-0.59, p=0.021). Respiratory disturbance index had a positive correlation with aortic stiffness (r=0.63, p=0.0001 and negative correlation with distensibility (r=-0.41, p=0.001). CONCLUSION: Aortic elastic parameters are deteriorated in OSA, which has an extremely high association with cardiovascular disease. Increased aortic stiffness might be responsible for the LV systolic and diastolic deterioration in OSA syndrome.     

Aortic stiffness, flow-mediated dilatation and carotid intima-media thickness in obstructive sleep apnea: non-invasive indicators of atherosclerosis

BACKGROUND AND OBJECTIVE: Obstructive sleep apnea (OSA) has a critical association with cardiovascular mortality and morbidity. Carotid intima-media thickness (IMT), flow-mediated dilatation (FMD) and aortic stiffness are early signs of atherosclerosis. The presence of subclinical atherosclerosis was assessed in OSA patients using these parameters. METHODS: 40 patients with OSA showing an apnea-hypopnea index (AHI) > or =5 (mean age 51.3 +/- 9 years, 32 males) and 24 controls (AHI < 5, mean age 51.9 +/- 5.2 years, 19 males) were enrolled in the study. In all subjects, polysomnographic examination and recordings were performed during sleep. IMT of the carotid artery, endothelium-dependent/-independent vasodilation of the brachial artery and aortic elastic parameters were investigated using high-resolution Doppler echocardiography. RESULTS: The demographic data of the patients with OSA and controls were not significantly different. Subjects with OSA demonstrated higher values of aortic stiffness (7.1 +/- 1.88 vs. 6.42 +/- 1.56, respectively) and IMT (0.85 +/- 0.13 vs. 0.63 +/- 0.11 mm, p = 0.0001, respectively) but lower distensibility (9.47 +/- 1.33 vs. 11.8 +/- 3.36 cm(2)/dyn/10(6)) and FMD (4.57 +/- 1.3 vs. 6.34 +/- 0.83%, p = 0.0001, respectively) than the controls. The respiratory disturbance index correlated positively with aortic stiffness and IMT and negatively with distensibility and FMD. CONCLUSION: We observed blunted endothelium-dependent dilatation, increased carotid IMT and aortic stiffness in patients with OSA compared with matched control subjects. This is evident in the absence of other diseases, suggesting that OSA is an independent cause of atherosclerosis. These simple and non-invasive methods help to detect subclinical atherosclerosis in OSA.     

Elastic properties of the ascending aorta in patients with beta-thalassemia major

BACKGROUND: Beta-thalassemia major (beta-TM) is a congenital hemolytic disorder characterized by impaired left ventricular and endothelial function. However, elastic properties of the aorta have not been sufficiently investigated in patients with beta-TM. We investigated whether beta-TM is related to impaired ascending aortic elastic properties. METHODS: We studied 36 patients with beta-TM (age: 15.8 +/- 2.6 years) and 30 age- and sex-matched control subjects by echocardiography. Aortic elastic indexes, aortic strain (%), distensibility (cm(2) dyn(-1) 10(-3)), and stiffness index were calculated from the echocardiographically derived thoracic aortic diameters (mm/m(2)), and the measurement of pulse pressure obtained by cuff sphygmomanometry. RESULTS: Patients versus control subjects had increased aortic diameters (P < 0.001), lower mean aortic strain (9 +/- 3.6 vs. 14.9 +/- 3.2, P < 0.001) and distensibility (0.6 +/- 0.36 vs. 0.8 +/- 0.2, P < 0.012), and higher mean stiffness index (5.3 +/- 2.4 vs. 2.8 +/- 0.6, P < 0.001). Aortic elastic indexes were significantly associated with ferritin level, while stiffness index was significantly related to platelet count. CONCLUSION: Elastic properties of ascending aorta are impaired in patients with beta-TM. Impaired functions of aorta may lead to deterioration of left ventricular function.     

Aortic elastic properties in patients with hypertensive response to exercise.

BACKGROUND: The aim of this study was to evaluate whether there is a relationship between aortic elastic properties in patients with a suggestive response to treadmill exercise testing. METHODS AND RESULTS: The study group comprised 32 patients suggesting hypertensive response to exercise and 20 patients suggesting normal blood pressure response to treadmill exercise testing. Baseline demographic characteristics were similar in both groups. However, the mean aortic stiffness index of patients suggesting hypertensive response to treadmill exercise testing was significantly higher (4.8+/-1.26 vs 2.36+/-1.09; p=0.001) whereas aortic distensibility was significantly lower (12.82 +/-5.84 vs 22.64+/-14.54; p=0.001) than the control group. The aortic strain of patients with hypertensive response to exercise was lower than the control group (12+/-3% vs 19.2+/-5%, p<0.001). The left ventricular mass (LVM) of these patients was also higher than control group (206.5+/-46.3 vs 134.2+/-19.97; p=0.01). A negative correlation between LVM and distensibility was found (r=-0.64; p=0.001) well as a positive correlation between LVM and aortic stiffness index (r=0.51; p=0.004) in patients suggesting hypertensive response to exercise. Pressure--rate product was also found to be correlated with LVM (r=0.47; p=0.006). CONCLUSION: Elastic properties of the aorta may be impaired in subjects showing exaggerated blood pressure response to exercise long before clinically manifest hypertension, particularly if the LVM is increased.     

Effect of long-term beta-blockade on aortic root compliance in patients with Marfan syndrome.

BACKGROUND: This study was undertaken to assess the effect of long-term beta-blockade on the aortic root stiffness index and distensibility in patients with Marfan syndrome. METHODS: Aortic root stiffness index and distensibility were calculated according to the formulas of Stefanadis and Hirai, respectively, with 2-dimensional guided M-mode echocardiogram before and after an average of 26 months of atenolol administration. RESULTS: Twenty-three asymptomatic patients were studied (11 men and 12 women, aged 31 +/- 14.2 years). The follow-up was 4 +/- 2.2 years. The dose of atenolol was individualized (mean 43.5 +/- 21.6 mg/d). Heart rate decreased from 79 +/- 9 beats/min to 64 +/- 9 beats/min (P =. 01), and systolic blood pressure decreased from 124 +/- 13 mm Hg to 114 +/- 2 mm Hg (P =.01). Distensibility increased from 1.85 +/- 0. 70 x 10(-6) cm2/dynes-1 to 2.21 +/- 0.76 x 10-6 cm2/dynes-1 (P =.02), and the stiffness index decreased from 9.68 +/- 3.78 to 8.85 +/- 3. 15 ( P =.2). Two groups of responses to treatment were identified. Compared with baseline values 15 (65%) patients who responded to treatment had increased distensibility and decreased stiffness index of the aortic root (P =.05). Eight patients (35%) who did not respond to treatment had no significant change. Body weight >91 kg and baseline end-diastolic aortic root diameter >40 mm were significantly associated with no response (P =.05). Two patients in the nonresponding group had echocardiographic progression of aortic insufficiency. CONCLUSIONS: There was a heterogeneous response in the aortic root elastic properties after long-term treatment with atenolol in asymptomatic patients with Marfan syndrome. Stiffness index and distensibility are more likely to respond when the baseline end-diastolic aortic root diameter is <40 mm.     

Aortic elastic properties and left ventricular diastolic function in patients with Adamantiades-Behcet's disease

OBJECTIVES: We investigated whether Adamantiades-Behcet's disease (ABD) is related to impaired aortic (Ao) elastic properties and left ventricular (LV) function. BACKGROUND: Adamantiades-Behcet's disease is an inflammatory disorder characterized by vasculitis leading to vascular complications and, rarely, myocarditis. METHODS: We studied 82 patients with ABD (age: 40 +/- 12 years) and 24 normal control subjects by echocardiography. Abdominal Ao diameter (mm/m(2)) and Ao elastic indexes--namely, Ao strain (%), distensibility (cm(2) x dyn(-1)x 10(-6)), stiffness index, and pressure strain modulus (Ep) (cm(2) x dyn(-1) x 10(-6))--were calculated from the echocardiographically derived thoracic Ao diameters (mm/m(2)), and the measurement of pulse pressure obtained by cuff sphygmomanometry. Isovolumic relaxation time (IVRT) (ms), deceleration time (DT) (ms), and flow propagation velocity (FPV) (cm/s) were measured by Doppler echocardiography to assess diastolic LV function. The duration of disease and presence of vascular complications were noted. RESULTS: Patients versus control subjects had increased Ao diameters (p < 0.01), lower mean Ao strain and distensibility (4 vs. 9 and 1.4 vs. 3.4, respectively, p < 0.01), higher mean aortic stiffness index and Ep (15.6 vs. 6 and 1.17 vs. 0.44, respectively, p < 0.01), and impaired IVRT and FPV (p < 0.01). Aortic function indexes were related to the duration of disease (p < 0.01) and increased DT (p < 0.01). Deceleration time >190 ms predicted vascular complications with 80% sensitivity and 71% specificity (odds ratio 6.52 [confidence interval: 2.23 to 19.03]). CONCLUSION: Aortic elastic properties and diastolic LV function are impaired in patients with ABD and are interrelated. The link between diastolic LV dysfunction and vascular complications suggests the presence of a common pathophysiologic pathway and provides a possible marker of risk for vascular disease.     

Aortic distensibility in post-stenotic aortic dilatation: the effect of co-existing coronary artery disease

Aortic distensibility is decreased in patients with coronary artery disease (CAD) and the angiographically normal aorta. To determine if the same is true in patients with aortic stenosis and post-stenotic dilatation, two groups were studied. Group A consisted of 15 patients with post-stenotic aortic dilatation and normal coronary arteries, and group B, 14 patients with post-stenotic aortic dilatation and CAD. The patients were compared to 18 normal subjects. The area of the first 6 cm of the aorta above the valve obtained by aortography was planimetered and the mean diameters were calculated. Distensibility was calculated using the formula: (formula; see text) Distensibility was greater in group A (2.5 +- .4 cm2.dynes-1) compared to group B (1.0 +- 8 cm2.dynes-1, p less than 0.001). Distensibility in normal subjects reported recently from this laboratory (3.4 +- .4 cm2.dynes-1) was greater compared to both groups A and B (p less than 0.001). Thus, distensibility was decreased in patients with post-stenotic aortic dilatation. The further decrease in distensibility in patients with co-existing coronary artery disease may be partially related to abnormal nutrition of the arterial wall since the vasa vasorum of the ascending aorta are derived from the coronary arteries.     

Color Doppler tissue imaging in assessing the elastic properties of the aorta and in predicting coronary artery disease

We hypothesized that the change in aortic elastic properties could directly be shown with color Doppler tissue imaging (CDTI), that these findings could be related to aortic stiffness and distensibility and that, through these, coronary artery disease (CAD) could be predicted. One hundred and twenty six patients (group I: 83 with CAD, mean age 54+/-10 years, 18 female, 65 male; group II: 43 without CAD, mean age 53+/-10 years, 27 female, 16 male) having been evaluated for coronary artery disease by angiography were examined by echocardiography. Arterial pressure was measured immediately before echocardiographic evaluation. Internal aortic systolic and diastolic diameters by M-mode echocardiography and aortic upper wall tissue velocities (Aortic S, E, A, m/sec) by CDTI were measured 3 cm above the aortic valve. Lateral mitral annulus tissue velocities (Annulus S, E, A, m/sec) were also recorded. Aortic distensibility (cm2 x dynes(-1)) and aortic stiffness index were calculated using formulas. In the statistical analyses, CAD risk factors and left ventricular ejection fraction were used for adjustment. Aortic stiffness (2.79+/-3.49 vs 1.62+/-1.31, P=0.03), distensibility (1.55+/-1.46 vs 2.37+/-3.08, P=0.04), and aortic S velocity (0.057+/-0.016 vs 0.064+/-0.015, P=0.02) differed significantly between groups I and II. After adjustment, while aortic stiffness and S velocity were still statistically different (P=0.04; P=0.03 respectively), the significance of the difference in aortic distensibility disappeared (P=0.051). Aortic stiffness and aortic S velocity (0.06 m/sec<) were important CAD determinants (Odds ratio=1.4 P=0.03; Odds ratio=3.6 P=0.01, respectively), but aortic distensibility was not. Aortic stiffness was correlated only with aortic S velocity (r=-0.28, P=0.01), and aortic distensibility had a significantly positive correlation with aortic S velocity (r=0.20, P=0.02). The interobserver and intraobserver correlation coefficients for aortic S velocities were 0.65 and 0.71, respectively (P<0.05). Elastic properties of the aorta can directly be assessed by reproducibly measuring the movements in the upper wall of the aorta by CDTI. Reduced aortic S velocity is associated with increased aortic stiffness. Increased aortic stiffness and reduced aortic S velocity are important predictors of CAD.     

Usefulness of colour tissue Doppler imaging in assessing aortic elastic properties in Type 1 diabetic patients.

AIMS: Diabetes mellitus (DM) is associated with macrovascular disease and impaired aortic function. We hypothesized that the change in aortic elastic properties could be investigated with colour tissue Doppler imaging (CTDI) in Type 1 diabetic patients and that these findings could be related to the aortic stiffness index. METHODS: We examined by echocardiography 66 patients with Type 1 DM (mean age 35 +/- 10 years, mean duration of disease 20 +/- 9 years) without a history of arterial hypertension or coronary artery disease (negative thallium-201 stress test) and 66 age- and sex-matched normal subjects. Arterial pressure was measured before echocardiography was performed. Internal aortic systolic and diastolic diameters by M-mode echocardiography and aortic systolic upper wall tissue velocity (Sao, cm/s) by CTDI were measured 3 cm above the aortic valve. Aortic distensibility and aortic stiffness index were calculated using accepted formulae. RESULTS: Aortic stiffness, distensibility and Sao velocity differed significantly between the studied groups. In the diabetic group, duration of diabetes correlated with aortic stiffness (r = 0.53, P < 0.001), distensibility (r = -0.61, P < 0.001) and Sao velocity (r = -0.48, P < 0.001). There was a negative correlation between aortic stiffness and Sao velocity (r = -0.49, P < 0.001). Multiple stepwise linear regression analysis in the diabetic group revealed that aortic S velocity (beta = 0.30, P = 0.005) and duration of diabetes (beta = -0.49, P = 0.001) were the main predictors of aortic distensibility (overall R(2) = 0.48). CONCLUSIONS: Aortic elastic properties can be directly assessed by measuring the movements in the upper aortic wall. Reduced aortic S velocity is associated with increased aortic stiffness in Type 1 diabetic patients.     

Usefulness of enalapril versus propranolol or atenolol for prevention of aortic dilation in patients with the Marfan syndrome

Despite variable clinical results, beta blockers have become the primary therapy for prevention of aortic dilation in patients with the Marfan syndrome. This study examines the use of the angiotensin-converting enzyme inhibitor enalapril for treatment of these patients. We sought to examine the effects of enalapril versus beta-blocker therapy in patients with the Marfan syndrome and noted improved aortic distensibility (3.0 +/- 0.3 vs 1.9 +/- 0.4 cm2 dynes(-1); p <0.02) and a reduced aortic stiffness index (8.0 +/- 2.9 vs 18.4 +/- 3.8; p <0.05) in patients receiving enalapril compared with those receiving beta blockers. These favorable hemodynamic changes were associated with a smaller increase in aortic root diameter (0.1 +/- 1.0 vs 5.8 +/- 5.2 mm) and fewer clinical end points during follow-up.     

Static versus dynamic distensibility of the carotid artery in humans

In clinical studies, the elastic behavior of central arteries is usually assessed by measuring dynamic distensibility. In this study, we aimed to investigate how dynamic and static distensibility of the common carotid artery (D(dyn) and D(stat), respectively) are related in 28 healthy volunteers of 20-71 years. The carotid diameter and its change with the pressure pulse were measured using an ultrasound echo-tracking device. Arterial blood pressure was measured by Finapres and carotid pressure was determined by applanation tonometry. D(dyn) was determined at rest using the pressure pulse, while D(stat) was determined during pressor responses induced by handgrip or cold pressor test. Data are given as mean +/- 1 SD. In younger subjects (<35 years), D(stat) did not differ from D(dyn) (7.0 +/- 3.4 vs. 6.5 +/- 2.1 x 10(-3) x mm Hg(-1), respectively), whereas in older subjects (>35 years), D(stat) was significantly higher than D(dyn) (3.8 +/- 1.4 vs. 2.1 +/- 0.9 x 10(-3) x mm Hg(-1), p < 0.001). For all subjects, D(stat) and D(dyn) decreased with increasing age and mean arterial pressure (MAP). Using stepwise multiple regression analysis, the strongest predictor of D(stat) proved to be MAP, while that of D(dyn) was age. D(stat) was found to be linearly related to the hysteresis loop area of the pressure-diameter relation (r = 0. 94), i.e. to vessel wall viscosity. It is concluded that, with increasing age, static distensibility overestimates the distension capacity of large arteries.     

Impaired aortic elastic properties in young patients with prehypertension

OBJECTIVES: 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. MATERIAL AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.