Comparison of the Biomechanical Properties of the Wall of an Aneurysmal-altered Abdominal Aorta According to the Results of in Vivo Ultrasound and an Associated Study of Strength Characteristics in Vitro

Study Overview
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Brief Summary
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Identification of the regression model between the strength properties of tissue and its ultrasonic spectral characteristics.

Detailed Description
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Patients with identified aneurysms of the abdominal aorta, who are planned for surgical treatment, undergo an ultrasound examination of the abdominal aorta to assess the elastic properties of the aortic wall using ultrasound speckle tracking. Intraoperatively, the accessible wall of the abdominal aortic aneurysm with a size of at least 10 cm2 is taken. and a section of the thrombotic cup of the aorta with a volume of up to 5 cm3. Pathologically altered tissues extracted for research are subject to removal during a standard operation for prosthetics of the infrarenal aorta and have no clinical significance for the patient. In in vitro studies, the strength properties of the aneurysm wall are measured under uniaxial tension on a tensile testing machine, which makes it possible to evaluate the elastic properties of the test sample and obtain such parameters as Young's modulus (slope of the strain-stress diagram in a linear section at small deformations), as well as limiting strain values and loading. The evaluation of the linearity boundaries of the surface under study, as well as the yield strength of the vascular wall and thrombotic masses, is evaluated under shear stresses using a rheometer. The tests will be carried out using special ground plane-to-plane instruments. To correlate the mechanical properties with the structural composition of the aneurysm tissue, spectral analysis of the tested tissues using the laser-induced fluorescence method and histological examination by staining the obtained sections for elastic fibers, fibrous tissues and calcification will be used.

Official Title
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Prospective Assessment of the Biomechanical Properties of the Wall of an Aneurysmal-altered Abdominal Aorta According to the Results of in Vivo Ultrasound and an Associated Study of Strength Characteristics in Vitro

Conditions
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the Strength Properties of the Aorta in Vivo, the Strength Properties of the Aorta in Vitro, Regression Model of Aortic Strength Properties in Vitro and in Vitro

Intervention / Treatment
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* Diagnostic Test: aneurysmectomy with sampling of a segment of the aneurysm wall


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with an aneurysmal expansion of the abdominal aorta who are indicated for surgery. Patients who consented to participate in this study Exclusion Criteria: Chronic heart failure III-IV functional class according to the NYHA classification; Chronic decompensated pulmonary heart; Severe hepatic or renal insufficiency (bilirubin > 35 mmol / l, glomerular filtration rate < 60 ml / min); Polyvalent drug allergy; Malignant oncological diseases in the terminal stage with a predicted lifespan of up to 6 months; Acute violation of cerebral circulation;

Ages Eligible for Study
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Minimum Age: 45 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: aneurysmectomy with sampling of a segment of the aneurysm wall|Patients with aneurysms of the abdominal aorta undergo an ultrasound examination of the abdominal aorta to assess the elastic properties of the aortic wall. The accessible wall of the abdominal aortic aneurysm is taken intraoperatively. In in vitro studies, the strength properties of the aneurysm wall are measured during uniaxial tension on a tensile testing machine, which makes it possible to evaluate the elastic properties of the test sample. The assessment of the boundaries of the linearity of the surface under study, as well as the yield strength of the vascular wall and thrombotic masses, is evaluated under shear stresses using a rheometer. To correlate the mechanical properties with the structural composition of the aneurysm tissue, spectral analysis of the studied tissues by laser-induced fluorescence and histological examination with staining of the obtained sections for the presence of elastic fibers, fibrous tissues and calcification will be used.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Calculate the relationship between the strength properties of the tissue and its ultrasonic spectral characteristics | Identification of the regression relationship between the elasto-elastic and strength properties of the tissue and its ultrasonic characteristics will make it possible to determine the most significant diagnostic ultrasonic criteria for aortic wall deformation, which determine the increased risk of its rupture and thromboembolic complications in a particular patient. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measurement of elastic-elastic properties of the aortic wall using ultrasonic speckle tracking | Patients with identified aneurysms of the abdominal aorta, who are planned for surgical treatment, undergo an ultrasound examination of the abdominal aorta to assess the elastic properties of the aortic wall using ultrasound speckle tracking. with the construction of a graph of elastic deformation segment by segment | at least one day prior to surgery | 
| Measurement of the strength properties of the aneurysm wall in uniaxial tension in vitro | evaluate the elastic properties of the tested sample and obtain parameters such as Young's modulus (the slope of the strain-stress diagram in the linear section at small strains) | 1 month | 
| Measure linearity limits as well as shear yield strength in vitro | The evaluation of the linearity boundaries of the surface under study, as well as the yield strength of the vascular wall and thrombotic masses, is evaluated under shear stresses using a rheometer | 1 month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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aneurysm wall strength, speckle tracking, shear yield strength