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Biomedical subjects

Harisios Boudoulas

Publications and source records attributed to Harisios Boudoulas.

At least 19 recordsLinked to original sources
PubMed2006

Relation between local temperature and C-reactive protein levels in patients with coronary artery disease: effects of atorvastatin treatment.

Although previous studies have shown systemic inflammatory activation the relation with the local plaque inflammatory activation has not been extensively studied. The present study investigated the relation between local and systemic inflammatory activation in patients with coronary artery disease and the impact of atorvastatin treatment. We included 215 patients undergoing percutaneous coronary intervention; of them 140 were treated with atorvastatin. Patients with stable angina (SA) and acute coronary syndromes (ACS) were included. Systemic inflammation was assessed by serum C-reactive protein (CRP), soluble adhesion molecules levels and local plaque inflammatory activation by coronary thermography. Temperature difference (DeltaT) was assigned as the difference between the proximal vessel wall temperature from the maximal temperature at the culprit plaque. Patients with ACS (n=78) had increased DeltaT compared to patients with SA (n=137) (0.16+/-0.10 degrees C versus 0.08+/-0.07 degrees C, P<0.001). Patients treated with atorvastatin had lower DeltaT compared to untreated patients (0.10+/-0.07 degrees C versus 0.15+/-0.10 degrees C, P<0.01). DeltaT was less in the treated group compared to the untreated group in patients with SA and ACS (ACS: 0.13+/-0.08 degrees C versus 0.20+/-0.11 degrees C, P<0.01, SA: 0.08+/-0.06 degrees C versus 0.13+/-0.08 degrees C, P=0.03). Although a correlation was found between CRP levels and DeltaT (R=0.29, P<0.01), in certain groups a discrepancy between CRP levels and DeltaT was observed. In 25% of patients with low DeltaT CRP levels were >1mg/dl and in 35.5% of patients with high DeltaT CRP was <2mg/dl. The correlation between soluble adhesion molecules and DeltaT did not reach statistical significance. Although there is a correlation between widespread and local inflammatory activation in patients with coronary artery disease, a discrepancy between culprit plaque and systemic inflammatory activation is observed. Atorvastatin has a parallel effect on systemic and local inflammatory process in patients with coronary artery disease.

Aged↗
PubMed2006

Mitral valvular regurgitation : etiology, pathophysiologic mechanisms, clinical manifestations.

The etiology of mitral valvular regurgitation (MVR) has changed in the last 40-50 years in the industrialized countries. A significant reduction in the incidence of rheumatic fever and its sequelae, increase in life expectancy, recognition of new causes of MVR, and advancement in technology are responsible for the metamorphosis of the etiology of MVR. It should be mentioned that MVR still constitutes a major health problem which will increase with the aging population. Recent advances in imaging techniques and hemodynamic studies allow clinicians to better define valvular structure and the pathophysiologic mechanisms of valvular heart disease in clinic practice. When combined with careful clinical history taking and thoughtful clinical examination, the correlation of laboratory studies with the clinical picture should permit definition of the etiology of valvular heart disease in the majority of the patients.

Humans↗
PubMed2006

Changes in aortic function after interposition of a tubular graft in the descending porcine thoracic aorta.

The objective of the study was to investigate the alterations of aortic function after interposition of a tubular graft in the descending porcine thoracic aorta. Eight healthy Landrace pigs were subjected to thoracotomy under sterile conditions. A 5-cm-long segment of descending thoracic aorta was replaced with a Dacron graft. Pulse wave velocity (PWV) was measured using simultaneous recordings of electrocardiogram and Doppler pressure waveforms, which were received from right carotid and femoral arteries. Then, the recordings were fed to a computer for analytical estimation of PWV in several occasions: right after the interposition (D0), and after 15 (D15) and 30 (D30) days time. Euthanasia was performed after the D30-recordings and the aortic graft area was removed. "Before graft" (BG) as well as "after graft" (AG) aortic regions were examined under light microscopy in order to determine the aortic thickness (T) and number of lamellar units (LU). Eight sham-operated pigs were used as controls. The results showed that PWV decreased as soon as the graft interposition took place and was maintained, until the end of experiment (P < 0.05). Aortic wall thickness was increased both at pregraft and postgraft areas (P < 0.05), and LUs were also increased at the same regions. It is concluded that the interposition of a tubular graft in the descending thoracic aorta resulted in a decrease in PWV, which may improve left ventricular performance and enhance myocardial perfusion, due to a delay in the arrival of the reflecting diastolic wave.

Animals↗
PubMed2005

A structural basis for the aortic stress-strain relation in uniaxial tension.

A constitutive law that includes three analytical expressions was recently proposed to approximate the low, physiologic, and high-stress parts of the aortic stress-strain relation in uniaxial tension, consistent with the biphasic nature of the aortic wall under passive conditions. This consistency, and the fact that previous phenomenological uniaxial laws have only indirectly been related to vessel wall structure, motivates the investigation of the structural basis underlying the newly proposed three-part constitutive law. For this purpose, longitudinally oriented aortic strips were fixed in Karnovsky's solution, while subjected to various pre-selected levels of uniaxial tensile stress. Light microscopy examination disclosed that the elastic lamellae gradually unfolded at low and were almost straight at physiologic and high stresses, while collagen fibers reoriented in the longitudinal axis at low, started uncoiling at physiologic, and straightened massively at high stresses. In the circumferential sections, the elastic lamellae and the circumferentially distributed collagen bundles remained wavy at all levels of longitudinally applied stress. These microstructural changes suggest that elastin becomes load-bearing at low, and collagen at physiologic but mostly at high stresses, so that the first and third parts of the constitutive law are in turn due to the presence of elastin and collagen alone, and the second due to both elastin and collagen. The structural basis of this constitutive law allows physically significant interpretation of its parameters, offering insight into how the aortic microstructure determines the macromechanical response.

Animals↗
PubMed2005

Post-vagotomy mechanical characteristics and structure of the thoracic aortic wall.

This study assessed the long-term effect of vagotomy on the structure and passive mechanical characteristics of the thoracic aorta under a wide range of stresses in vitro. Eight healthy Landrace pigs underwent bilateral vagotomy distal to the origin of the recurrent laryngeal nerve, and 10 pigs were sham-operated. Three months post-surgery, the aorta was excised and specimens from the ascending aorta, arch, and descending thoracic aorta were subjected to histomorphometrical evaluation and uniaxial tensile-testing until failure. Elastic modulus-stress data were plotted and submitted to regression analysis. Structural remodeling after vagotomy was characterized as vascular growth in the ascending aorta and arch, and as thinning in the descending thoracic aorta. In the aortic segments of vagotomized animals, the area density of elastin and collagen was increased, but smooth muscle density was decreased. Similar differences in regression parameters and failure strength between groups were found in all aortic segments, indicating that the vessel wall was stiffer and stronger in vagotomized animals. In the clinical setting, disease states or drugs blocking the regulatory role of the vagi nerves on the aortic wall may have undesirable consequences on the mechanical performance of the thoracic aorta, and therefore on hemodynamic homeostasis.

Animals↗
PubMed2004

Effect of cold, isometric exercise, and combination of both on aortic pulse in healthy subjects.

The aortic pulse-wave velocity (PWV) and augmentation index were measured in 24 healthy adults at baseline, during a cold pressor test (CPT), during hand-grip isometric exercise test (HIE), and during a combination of CPT plus HIE. The PWV and augmentation index increased significantly during CPT and HIE compared with baseline (p <0.01). The combined effect of CPT and HIE on PWV and augmentation index was greater compared with the effect of each intervention alone.

Adult↗
PubMed2003

Effect of static magnetic field exposure of up to 8 Tesla on sequential human vital sign measurements.

PURPOSE: To determine if increasing static magnetic field strength exposures up to 8 Tesla (T) affect vital signs or electrocardiograms (ECGs) in normal human volunteers. MATERIALS AND METHODS: We studied 25 normal subjects, consisting of 19 men and six women, ages 24-53 years. The vital signs and ECGs of the subjects were measured 14 times inside and outside the magnetic field. This included the heart rate, respiratory rate, systolic and diastolic blood pressures, finger pulse oxygenation levels, core body temperature via the external auditory canal temperature, and fiber optic core body sublingual temperatures. Inside the magnetic field the vital signs were measured sequentially at field strengths of 8, 6, 4.5, 3, and 1.5 T. RESULTS: The only statistically significant effect of magnetic field strength was observed with systolic blood pressure. An average increase of 3.6 mm Hg in systolic blood pressure was seen with 8 T exposure. ECG rhythm strip analysis demonstrated no significant changes post-exposure. CONCLUSIONS: Normal subjects exposed to varying magnetic field strengths of up to 8 T demonstrated no clinically significant changes in vital signs. Transient ECG artifacts were noted to increase with the field strength.

Adult↗
PubMed2003

Factors determining left atrial kinetic energy in patients with chronic mitral valve disease.

BACKGROUND: Increased left atrial (LA) work is a major contributor to LA fatigue, LA failure and atrial fibrillation in patients with mitral stenosis (MS) and mitral valvular regurgitation (MVR). The present study was undertaken to define factors that determine LA work in patients with chronic mitral valve disease. PATIENTS AND METHODS: Peak left atrial kinetic energy (LAKE)was used as an index of LA work in 14 patients with MS, 14 with MVR, and 19 normal subjects matched for age and gender with MS and MVR patients. LA stroke volume and ejection fraction were measured from the biplane area-length method using echo techniques. Peak LAKE was obtained from the formula 1/2 mv2, where m = LA stroke volume x 1.06 (blood's specific gravity) and v = transmitral Doppler A-wave velocity. RESULTS: Stepwise regression analysis often clinical and echocardiographic parameters demonstrated that in MS, mitral valve area (r2 = 0.43) and LA maximal volume (r2 = 0.62), in MVR, only LA maximal volume (r2 = 0.42) contributed independently to LAKE. LAKE was greater in MS and MVR compared to control subjects while LA ejection fraction was similar in all groups. CONCLUSIONS: It is concluded that LA work is markedly increased in patients with chronic mitral valve disease. Increased LA work in chronic mitral valve disease may contribute to LA fatigue, LA failure, and atrial fibrillation.

Adult↗
PubMed2003

Long-term treatment effect of atorvastatin on aortic stiffness in hypercholesterolaemic patients.

AIM: To assess the effect of atorvastatin on aortic stiffness in hypercholesterolaemic patients free of arterial hypertension and diabetes mellitus. METHODS AND RESULTS: The study included 36 patients (25 men and 11 women, mean age 56 +/- 12 years); 18 patients had stable coronary heart disease (CHD) and 18 were free of CHD at baseline. All patients received atorvastatin (20 mg/day) for a 2-year period. Aortic stiffness was assessed by transthoracic echocardiography at baseline and 2 years later. At baseline, total cholesterol, low density lipoprotein cholesterol (LDL-C) and LDL-C/high density lipoprotein cholesterol (HDL-C) ratio were positively related to aortic stiffness (p < 0.001 for all). The mean change in lipid parameters during treatment was: total cholesterol -38%, LDL-C -46%, triglycerides -29%, and HDL-C +6%, all significant (p = 0.029 to < 0.0001). After the 2-year treatment with atorvastatin, aortic stiffness was significantly reduced by 14% (p = 0.019). An improvement of left ventricular (LV) ejection fraction by 13% (p < 0.001) and a reduction of LV mass index by 9% (p = 0.008) were also recorded. The change in aortic stiffness was similar in patients with or without CHD. CONCLUSION: Long-term treatment with atorvastatin improves aortic stiffness; this index is related to total and coronary mortality. Moreover, assessment of aortic stiffness may be useful in identifying which hypercholesterolaemic patients should be treated aggressively, regardless of CHD. The aortic stiffness effect may eventually become an index of the efficacy of lipid lowering treatment.

Adult↗
PubMed2003

Etiology of valvular heart disease.

The etiology of valvular heart diseases (VHD) has changed in the last 50 years in the industrialized countries. A significant reduction in the incidence of rheumatic fever and its sequelae, increase in life expectancy, recognition of new causes of VHD and advancement in technology are responsible for the metamorphosis of the etiology of VHD. Heritable disorders of connective tissue (marfan syndrome, Ehlers-Danlos syndrome, adult polycystic kidney disease, floppy mitral valve/mitral valve prolapse); congenital heart disease (bicuspid aortic valve); inflammatory/immunologic disorders (rheumatic fever, AIDS, Kawasaki disease, syphilis, seronegative spondyloarthropathies, systemic lupus erythematosus, antiphospholipid syndrome); endocardial disorders (nonbacteremic thrombotic endocarditis, infective endocarditis, endomyocardial fibroelastosis); myocardial dysfunction (ischemic heart disease, dilated cardiomyopathy, hypertrophic cardiomyopathy); diseases and disorders of other organs (chronic renal failure, carcinoid heart disease); aging (calcific aortic stenosis, mitral annular calcification); postinterventional valvular disease; drugs and physical agents are all clinical entities associated with VHD. It should be emphasized that VHDs still constitute a major health problem which will increase with the aging population.

Heart Valve Diseases↗
PubMed2003

Long-term cardiovascular effects of insulin sensitizer troglitazone on non-diabetic individuals with insulin resistance: double blind, prospective randomized study.

OBJECTIVES: The study was undertaken to assess the long-term cardiovascular effects of troglitazone on non-diabetic individuals with insulin resistance. BACKGROUND: It has been suggested that treatment with troglitazone or similar insulin-sensitizing agents may prevent cardiovascular complications in non-diabetic individuals with insulin resistance. However, the long-term cardiovascular effects of these agents on non-diabetic individuals remain to be defined. METHODS: A total of 137 African-American offspring of type 2 diabetic parents, with normal glucose tolerance and insulin resistance, were randomly divided to receive troglitazone 200 mg/day (n = 40), or placebo (n = 97) for 24 months. Brachial artery blood pressure (sphygmomanometry); aortic pulse wave velocity (carotid to femoral artery, Doppler), left ventricular diameters and mass (echocardiography); ascending and abdominal aortic distensibility (echocardiography, blood pressure); and metabolic and lipid profile were assessed at baseline, 12, and 24 months after randomization (delta 12, delta 24 respectively). RESULTS: The pulse wave velocity increased significantly in the troglitazone group compared to placebo group (p < 0.05). Changes from baseline in the troglitazone group were significant (delta 12 = 1.09 +/- 0.36 m/sec, delta 24 = 2.08 +/- 0.45 m/sec, ANOVA p < 0.001), while pulse wave velocity remained unchanged in the placebo group. This increase in pulse wave velocity is consistent with a decrease in the elastic properties of the aorta. CONCLUSIONS: Long-term administration of troglitazone to non-diabetic African-Americans with insulin resistance was associated with a decrease in the elastic properties of the aorta. Long-term therapy with troglitazone or similar agents for the prevention of cardiovascular complications in non-diabetic individuals with insulin resistance has to be critically evaluated.

Adult↗
PubMed2002

Assessment of the aortic stress-strain relation in uniaxial tension.

The passive elastic characteristics of the abdominal aorta were investigated in two experimental animal models, aiming at assessing the stress-strain relation of the aortic wall. Twenty porcine and 15 rabbit healthy abdominal aortas were subjected to uniaxial stress-strain analysis, performed on a tensile-testing device, while immersed in a physiologic saline bath at body temperature. Measured parameters included original length, width and thickness, as well as axial force and extension. Based on these data, Kirchhoff stress and Green-St.Venant strain were computed and one-dimensional constitutive equations were defined, comprising of a power function and two exponential ones, in turn, for the low, physiologic and high-stress regions. The stress-strain curves were plotted as elastic modulus versus stress, displaying nonlinear part I and linear parts II and III. These were regressed, yielding parameters k, q (part I), a, b (part II) and c, d (part III). A detailed comparison of these constitutive parameters was undertaken between the two species, demonstrating variations in d (p<0.05). No statistical differences were found in parameters a, b, c, k and q, implying that the two aortas were equally stiff under low and physiologic stresses, whereas the porcine aorta was stiffer at higher stresses. In conclusion, a bi-exponential in addition to a power law was established, relating stress and strain in the aorta, which is advantageous in comparison with previous constitutive equations. Under passive conditions, the nonlinear nature of this constitutive law may account for the low, part I, physiologic, part II, and high-stress, part III of the stress-strain relationship, supporting the concept of the aortic wall as a biphasic material.

Animals↗
PubMedDate not supplied

Cardiovascular effects of type 1 diabetes mellitus in children.

Previous studies have shown that type 1 diabetes mellitus (DM) is associated with cardiovascular abnormalities. Early detection and treatment of these abnormalities may help to prevent the natural progression of the disease. The present study was undertaken to define early cardiovascular abnormalities in children with type 1 DM. Simultaneous evaluation of multiple cardiovascular parameters was performed in 14 children with type 1 DM and 14 age-and gender-matched normal subjects. Measurements of carotid artery intima-media thickness (cIMT, echocardiography), carotid and aortic (ascending and abdominal) distensibility (echocardiography, brachial artery blood pressure), aortic pulse wave velocity (carotid to femoral artery, Doppler), and left ventricular dimensions, mass, and function (echocardiography) were performed. Diabetic children demonstrated a greater cIMT (0.36 +/- 0.04 mm vs 0.31 +/- 0.03 mm, p = 0.002) and decreased carotid artery distensibility (4.4 +/- 1.6 cm(2) . dynes(-1) . 10(-6) vs 6.0 +/- 1.9 cm(2) . dynes(-1) .10(-6), p < 0.01) compared to control. Aortic pulse wave velocity was increased in DM (6.70 +/- 0.39 vs 6.30 +/- 0.31, p = 0.02) compared to control. Left ventricular diameters, mass, and systolic and diastolic function did not differ between the 2 groups. Simultaneous assessment of multiple cardiovascular parameters in children with type 1 DM revealed impaired carotid artery structure and function, and decreased elastic properties of the aorta, before demonstrable changes in left ventricular structure and function could be detected.

Adolescent↗