Surgical indication in patients suffering from Ascending aorta aneurysm is currently based mainly on the maximum diameter of the aortic dilatation and on the yearly growth rate. Several clinical preoperative patients characteristics have been, potentially, correlated to impaired mechanical characteristics of aortic wall, and therefore to an increased risk of rupture and or dissection. On other hands, such suppositions have been never confirmed, as a full characterization of the mechanical behaviour of the ascending aortic tissue, especially in case of aneurysm, has not been fully clarified yet. Objective of this observational study is to better elucidate, using direct in vivo evaluation, the mechanical characteristics of the aortic wall in patients with ascending aorta diseases. Our study will have a further peculiar characteristic as we have the intention of compare such mechanical characteristics to those of patients, without known aortic diseases, undergoing heart transplantation. Potential correlation between, directly measured mechanical characteristics of the aortic wall, and preoperative parameters (anagraphic patients characteristics, clinical data and diagnostic tests) will be also investigated.
Patients undergoing surgery including ascending aorta replacement at our Department and/or heart transplantation
Patients with biological hazard (HBC/HIV +)
The primary study population consisted of patients referred for ascending aortic/aortic root dilation surgery. The study evolved to include control groups including patients with acute aortic dissection and patients without aortic disease undergoing heart transplantation.
Case-control
Prospective
Not listed
Identification of extreme aortic wall fragility in relation to demographic or pathological characteristics of the enrolled patients.
The execution of the above tests, and the following analysis and post-processing of the tests response will allow the characterization of ultimate mechanical properties using three main parameters: 1. Peak Strein (the maximum strein before specimen rupture) 2. Peak Stress (the maximum stress before specimen rupture) 3. Maximum Elastic Modulus (the maximum slope of the stress-strain curve The identification of extreme aortic wall fragility will be based primarily on extreme values of the first two parameters (\<25th percentile). For the third parameter, both extreme values (\<25th and \>75th percentile) will be considered. As a further parameter of fragility, an abnormal increase in intra-patient variability will also be considered, in case of the possibility of multiple tests.
Ex-vivo evaluation of mechanical properties of aortic wall in patients with and without aortic diseases undergoing cardiac surgery procedure.
Uniaxial and biaxial tensile tests to failure of fresh specimens collected during cardiac surgery and transferred (within 24 hours) to the Department of Civil Engineering and Architecture of the University of Pavia. The execution of the above tests, and the following analysis and post-processing of the tests response will allow the characterization of ultimate mechanical properties using three main parameters: 1. Peak Strein (the maximum strein before specimen rupture) 2. Peak Stress (the maximum stress before specimen rupture) 3. Maximum Elastic Modulus (the maximum slope of the stress-strain curve) . Test results will ultimately be correlated with patient demographics and specific disease patterns (e.g. presence and extent of aortic dilation, combined aortic valve disease, acute aortic dissection). The final aim of the study is the potential identification of predictive factors for increased risk of acute aortic events.
Ex vivo evaluation of aortic wall mechanical characteristics in patients with and without aortic disease.
Fresh aortic wall samples taken during surgery are sent within 24 hours at the Department of Civil Engineering and Architecture of the University of Pavia where uniaxial and biaxial mechanical test at rupture are completed. The execution of the above tests, and the following analysis and post-processing of the tests response will allow the characterization of ultimate mechanical properties using three main parameters: 1. Peak Strein (the maximum strein before specimen rupture, expressed as mm-mm) 2. Peak Stress (the maximum stress before specimen rupture, expressed as MPa) 3. Maximum Elastic Modulus (the maximum slope of the stress-strain curve, expressed as a ratio mm-mm/MPa). The test results will then be correlated with the patients' demographic characteristics and with the characteristics of the disease to highlight potential predictors of greater fragility of the aortic wall and increased risk of acute events.
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