Aortic elastic properties in young pregnant women

This study aimed to investigate the aortic elastic properties of young pregnant women by comparing them with those of age-matched healthy females. The study group consisted of 21 pregnant women at a mean age of 26 ± 1 years; 22 healthy women at a mean age of 25 ± 1 years constituted the control group. Doppler-color echocardiographic variables and serum estradiol (E2) levels were measured from both groups. The blood samples were obtained from the control group in the first week after menstrual bleeding. Diastolic and systolic blood pressure (DBP and SBP, respectively) were measured with a sphygmomanometer. Systolic and diastolic aortic diameters (AOS and AOD, respectively) were measured 3 cm proximal to the aortic valves. Aortic elastic properties were assessed according to the following formulas: 1, Aortic strain = (AOS − AOD)/AOD; 2, Aortic distensibility = 2 × (AOS − AOD)/(PP × AOD); 3, Aortic diameter change = AOS − AOD; 4, Aortic stiffness index = ln(SBP/DBP)/(AOS − AOD)/AOD. The results were expressed as mean ± standard deviation and compared by t-test between groups. P < 0.05 was considered as statistically significant. All women in the study group were in their first pregnancy and second trimester. The height and weight were 160 ± 5 vs 164 ± 6 cm and 60 ± 9 vs 54 ± 3 kg in the study vs control groups, respectively (P < 0.05). The AOD was 26 ± 3 vs 26 ± 4 mm and AOS 29 ± 3 vs 28 ± 4 mm. Pulse pressure was 43 ± 3 vs 45 ± 8 mmHg in the study vs control groups, respectively (P > 0.05). The serum E2 level was significantly higher in pregnant women (21 300 ± 2 300 pg/ml). Derived aortic elastic properties in pregnant women were also increased significantly (P < 0.0005). The indexes of aortic elastic properties are altered and aortic stiffness is decreased among young pregnant women. This may be due to the adaptation mechanisms including high estradiol levels detected in pregnancy. This study was presented as an oral presentation at the XXth Turkish Society of Cardiology Meeting (November 27–30, 2004) in Antalya, Turkey     

Aortic elastic properties in athletes using anabolic-androgenic steroids

Adipocytokine levels and visceral adipose tissue (VAT) seem to be associated with some cardiac abnormalities and a role of visceral fat in predisposing to cardiac dysfunction, possibly through a low-grade state of inflammation, has been demonstrated. In this study we firstly show that elevated levels of both monocyte chemoattractant protein 1 (MCP-1) and soluble IL-6 receptor/interleukin-6 (sIL-6R/IL-6) complex are closely correlated with epicardial fat thickness.     

Aortic elastic properties in patients with coronary artery ectasia.

BACKGROUND: The purpose of the present study was to investigate the elastic characteristics of the aorta in patients with coronary ectasia (CE) and the relationship between these characteristics and echocardiographic left ventricular (LV) diastolic functions. METHODS AND RESULTS: In the first group there were 35 patients with CE, the second group consisted of 35 patients with coronary artery disease (CAD) and the third group consisted of 35 patients with normal coronary arteries. Echocardiographic investigation was carried out for the assessment of the LV diastolic functions. Aortic strain, beta index and aortic distensibility were used as aortic elasticity parameters. LV diastolic functions were impaired in both the ectasia group and the CAD group as compared with patients with normal coronary arteries. Beta index and aortic distensibility measurements were similar between the CAD and CE groups. The values obtained for aortic strain, beta index and aortic distensibility were lower in the CAD and ectasia groups when compared with the values of the normal group. On performing the stepwise linear multivariable analyses, aortic elastic parameters have been determined to possess the strongest diagnostic power for LV diastolic functions. CONCLUSIONS: The results of the current study show that stiffness parameters of aorta are impaired in the patients with CE as in the patients with CAD. The increase in aortic stiffness might be responsible for LV diastolic dysfunction.     

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.     

Aortic elastic properties and left ventricular diastolic function in white-coat hypertensive individuals

OBJECTIVES: Although white-coat hypertension may be present in 25% or more of hypertensive individuals, its prognostic significance and predisposition to end organ damage is unknown. To evaluate whether white-coat hypertension is associated with end organ damage, we compared prognostically relevant measures of target-organ damage among 35 individuals with white-coat hypertension and age and sex-matched groups of sustained hypertension and normotensive individuals classified by clinical and 24-h ambulatory blood pressures. METHODS: We evaluated left ventricular diastolic function and aortic elastic properties of 35 individuals with white-coat hypertension, 50 patients with sustained hypertension, and 35 normotensive healthy volunteers using transthoracic Doppler echocardiography. None of the study participants with sustained hypertension and white-coat hypertension, who were newly diagnosed and never treated, had any systemic disease or coronary risk factor except hypertension. RESULTS: Age, sex, and body mass indexes were similar among the three groups. Left ventricular diastolic function was more significantly impaired in the sustained hypertension and white-coat hypertension groups than in the control group, but it was not significantly different between the white-coat hypertension and sustained hypertension groups. Aortic distensibility was significantly lower, and aortic stiffness index was significantly higher in the sustained hypertension group than in the white-coat hypertension and control groups. Furthermore, aortic elastic properties were slightly impaired in the white-coat hypertension group compared with those in the control group. We also found a significant correlation between aortic elastic properties and left ventricular diastolic function. CONCLUSIONS: White-coat hypertension may alter left ventricular diastolic function and aortic elastic properties. These alterations, however, might not be as remarkable as those caused by sustained hypertension. In this respect, individuals with white-coat hypertension are not at such a risk for end organ damage as patients with sustained hypertension.     

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 elastic properties and left ventricular diastolic dysfunction in patients with obstructive sleep apnea

Although the responsible mechanisms are not yet fully known, obstructive sleep apnea is associated with an increased risk for cardiovascular disease and events. The aorta is not only a conduit delivering blood to the tissues but is also an important modulator of the entire cardiovascular system, its elastic properties also affecting left ventricular function and coronary blood flow. The aim of this study was to determine left ventricular diastolic function and aortic elastic properties in patients with obstructive sleep apnea syndrome. Fourteen male patients with obstructive sleep apnea and 14 age- and body mass index-matched healthy male controls took part in the study as a control group. All subjects underwent echocardiographic examination; left ventricular cavity dimension, standard and tissue Doppler parameters, and aortic diameter (3 cm above aortic valve) at systole and diastole were measured. While the aortic stiffness index in patients with obstructive sleep apnea was significantly higher than that of the control group (4.5 ± 0.3 vs 2.1 ± 0.1, P = 0.001), the aortic distensibility index was found to be lower in this group compared with controls (2.4 ± 1.2 vs 3.9 ± 1.5 cm² dynes⁻¹ 10⁻⁶, P = 0.009). Furthermore, peak velocity of myocardial systolic wave and peak velocities of myocardial diastolic waves in sleep apnea patients were lower than in controls. There was an association between aortic stiffness and the apnea hypopnea index (coefficient = 0.49, P = 0.002). We also found an inverse correlation between peak velocity of myocardial diastolic wave and aortic stiffness (coefficient = −0.43, P = 0.003), using multiple linear regression. Increased aortic stiffness that is associated with the severity of disease in patients with obstructive sleep apnea may lead to diastolic dysfunction of the left ventricle.     

Aortic root dilation and aortic elastic properties in children after repair of tetralogy of Fallot

Analyses of aortic specimens obtained from patients with tetralogy of Fallot (TOF) revealed elastic fiber fragmentation. This study sought to determine the prevalence of aortic root dilation and aortic regurgitation (AR) in children after TOF repair and tested the hypothesis that aortic elastic properties are altered and related to aortic root dilation in these patients. Aortic dimensions, adjusted for body surface area and expressed as z scores, and AR were assessed echocardiographically in 67 children 8.3 +/- 5.6 years after TOF repair. The aortic elastic properties were compared with those in 50 age-matched controls. The prevalence of aortic dilation (z score >2) was 88%, 87%, 61%, and 63% at the annulus, sinus of Valsalva, sinotubular junction, and ascending aorta, respectively. The z scores of the annulus (r = 0.41, p <0.001) and sinus (r = 0.33, p <0.01) were correlated with body surface area. Multivariate analysis identified the duration of follow-up after surgery as the only significant determinant of z scores of the annulus (beta = 0.41, p = 0.001) and sinus (beta = 0.33, p = 0.009). AR was present in 12% of patients who tended to have larger z scores at all aortic levels. Compared with controls, patients had significantly increased aortic stiffness (p <0.001) and reduced strain (p <0.001) and distensibility (p = 0.002). Aortic stiffness was correlated positively, whereas aortic strain and distensibility were correlated negatively, with the aortic root z scores at all levels. In conclusion, this study shows a high prevalence of aortic root dilation in children after the repair of TOF. Aortic stiffening occurred in these patients and may play a role in progressive aortic root dilation.     

Aortic elastic properties in athletes with Marfanoid habitus: the need for early and accurate diagnostic methods.

It was with great interest that I read the paper by Nollen et al.¹on the predictive value of aortic stiffness on the occurrenceof progressive aortic dilatation in patients with Marfan     

Aortic medial elastic fiber loss in acute ascending aortic dissection

The cause of acute aortic dissection continues to be debated. One school of thought suggests that underlying aortic medial cystic necrosis is the common denominator. The purpose of the present study was to determine if there was loss and, if so, how much loss of medial elastic fibers in the ascending aorta in patients with acute aortic dissection with the entrance tear in the ascending aorta. We examined operatively excised ascending aortas in 69 patients having acute dissection with tears in the ascending aorta. Patients with previous aortotomy, healed dissection, and connective tissue disorders were excluded. The 69 patients' ages ranged from 31 to 88 years (mean 56); 49 were men and 20 were women. Loss of aortic medial elastic fibers was graded as 0 (no loss), 1+ (trace), 2+ (mild), 3+ (moderate), and 4+ (full thickness loss). Of these 69 patients, 56 (82%) had 0 or 1+ elastic fiber loss; 13 patients (18%), 2+ to 4+ loss including 4 with 2+, 6 with 3+, and 2 with 4+. Nearly all patients (97%) had a history of systemic hypertension and/or had received antihypertensive drug therapy. In conclusion, most patients (82% in this study) having acute aortic dissection with entrance tears in the ascending aorta have normal numbers or only trace loss of aortic medial elastic fibers. Thus, underlying abnormal ascending aortic structure uncommonly precedes acute dissection.     

Docosahexaenoic acid alters bilayer elastic properties

At low micromolar concentrations, polyunsaturated fatty acids (PUFAs) alter the function of many membrane proteins. PUFAs exert their effects on unrelated proteins at similar concentrations, suggesting a common mode of action. Because lipid bilayers serve as the common "solvent" for membrane proteins, the common mechanism could be that PUFAs adsorb to the bilayer/solution interface to promote a negative-going change in lipid intrinsic curvature and, like other reversibly adsorbing amphiphiles, increase bilayer elasticity. PUFA adsorption thus would alter the bilayer deformation energy associated with protein conformational changes involving the protein/bilayer boundary, which would alter protein function. To explore the feasibility of such a mechanism, we used gramicidin (gA) analogues of different lengths together with bilayers of different thicknesses to assess whether docosahexaenoic acid (DHA) could exert its effects through a bilayer-mediated mechanism. Indeed, DHA increases gA channel appearance rates and lifetimes and decreases the free energy of channel formation. The appearance rate and lifetime changes increase with increasing channel-bilayer hydrophobic mismatch and are not related to differing DHA bilayer absorption coefficients. DHA thus alters bilayer elastic properties, not just lipid intrinsic curvature; the elasticity changes are important for DHA's bilayer-modifying actions. Oleic acid (OA), which has little effect on membrane protein function, exerts no such effects despite OA's adsorption coefficient being an order of magnitude greater than DHA's. These results suggest that DHA (and other PUFAs) may modulate membrane protein function by bilayer-mediated mechanisms that do not involve specific protein binding but rather changes in bilayer material properties.     

Reexamination of the elastic properties of emphysematous lungs

We calculated specific lung elastance (Es,L) as the change of lung elastic recoil pressure (Pel,L) required to produce a given fractional change in lung volume (delta VL/VL,0) as a function of transpulmonary pressure (PL) from published data in normal lungs, and in patients with chronic obstructive pulmonary disease (COPD) or alpha 1-antitrypsin deficiency (alpha 1-AD). Es,L, in normal lungs, is the bulk modulus, and was systematically greater than PL.dEs,L/dPL increased with VL.PL at Es,L = 30 cm H2O decreased with age in normal lungs, but Es,L at PL = 8 cm H2O showed no age relationship. In both COPD and alpha 1-AD Es,L and dEs,L/dPL were increased compared to normal lungs. We conclude that Es,L is a curvilinear function of PL in normal lungs, COPD and alpha 1-AD, and is systematically greater than PL. The increase in Es,L and dEs,L/dPL in COPD and alpha 1-AD compared to normals probably represents two distinct abnormalities in the elastic properties of emphysematous lungs: (1) an increase in resting length of alveolar walls accounting for hyperinflation, and (2) a decrease in extensibility of alveolar walls once they become stressed. Using total lung capacity (TLC) as an index of the former and Es,L as an index of the latter, we showed no correlation between either and FEV1. Thus abnormalities in lung elastic properties in emphysema do not account for chronic expiratory flow limitation in emphysema. Furthermore, the increased values of Es,L in emphysema suggest that emphysematous airspaces are poorly ventilated. As they are presumably poorly perfused, emphysema per se may not disturb ventilation perfusion ratios seriously.     

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.     

Bicuspid aortic valve: abnormal aortic elastic properties

BACKGROUND AND AIMS OF THE STUDY: Bicuspid aortic valve (BAV) is frequently associated with clinically relevant abnormalities of the aorta, suggesting the existence of a common underlying developmental defect involving the aortic valve and wall of the ascending aorta. The study aim was to evaluate noninvasively the elastic properties of the aortic root in young males with BAV, to discover whether structural abnormalities of the aorta might be manifested by impairment in elasticity. METHODS: Forty-nine young male subjects with isolated BAV were consecutively detected during preenrollment military screening, and studied using transthoracic echocardiography. Data were compared with those obtained in 45 normal subjects, matched for gender and age. RESULTS: Patients and controls were comparable for body size, and systolic and diastolic blood pressures. BAVs were normally functioning in 18 patients (37%), and mildly regurgitant in 31 (63%). Measurements made by two-dimensional echocardiography showed that BAV patients had significantly larger aortic root dimensions at the annulus (2.4+/-0.2 versus 2.2+/-0.2 cm, p <0.001), at the sinus of Valsalva (3.3+/-0.4 versus 2.6+/-0.3 cm, p <0.001), at the sinotubular junction (2.9+/-0.3 versus 2.5+/-0.2 cm, p <0.001), and at the proximal ascending aorta (2.8+/-0.3 versus 2.5+/-0.2 cm, p <0.001). Measurements made using M-mode echocardiography at 3 cm from the annulus, showed the difference between systolic and diastolic diameters of the aortic root to be significantly smaller in patients than in controls (2.1+/-1.2 versus 3.0+/-1.1 mm, respectively, p <0.001). In patients and in controls, both aortic distensibility (2.7+/-1.5 versus 4.8+/-2.2 x 10(-6) cm2 dyne(-1), respectively, p <0.001) and aortic stiffness index (10.2+/-5.3 versus 5.03+/-1.97, respectively, p <0.001) were significantly different. CONCLUSION: Young male subjects with BAV and no or mild aortic regurgitation display large aortic size and abnormal elastic properties of the ascending aorta compared with controls. These findings confirm the notion that, in these patients, aortic root dilatation is a morphological correlate of intrinsic structural aortic abnormality.