Acute Type A Dissection Clinical Trial
Official title:
Mechanical Characterization of Ascending Aorta in Patients With Acute Type A Dissection and in Healthy Control Group Combined to Structural and Ultrastructural Analysis of Aortic Tissue
Acute type A aortic dissection is a frequent (3 cases per 100 000 people per year) and severe (spontaneous mortality 70%), needing an emergency surgical treatment. Surgical outcomes have improved with the development of surgical techniques, but the postoperative mortality remains high (15-30% at 30 days). Endovascular approach with the deployment of endoprosthesis sealing the proximal intimal tear is an attractive minimally invasive technique, which can represent an alternative to surgical repair especially in high risk patients.
Objectives: this study aims to characterize mechanical properties of ascending aorta (AA) in
patients, with and without aortic dissection.
Materials and methods : comprised an in vivo and ex vivo studies performed in 2 groups of
patients : (1) patients admitted for acute type A dissection and treated with surgical
procedure ; (2) healthy control group selected among patients without any ascending aorta
pathology and who underwent transoesophageal echocardiography for various indications.
In vivo study : Strain, distensibility, stiffness index and pressure strain elastic modulus
(Ep) were calculated from aortic diameter variation in response to pressure variation.
Aortic diameters were measured using transoesophageal echocardiography.
Ex vivo study : biaxial tensile testing were performed on aortic wall samples. Dissected
aortic samples were collected from patients who underwent surgical repair and healthy
samples from unused donors hearts and lungs. Mechanical characterization was combined to a
histological and microstructural analysis of aortic wall. The latter was conducted using
multiphoton microscopy to visualize elastin and collagen fibers.
Results :
In vivo study: 22 patients in healthy control group and 13 patients in dissection group were
prospectively investigated.
In vitro study : Biaxial testing was performed on 4 samples of dissected aorta and 6 samples
of non dissected aorta. Anisotropic and non linear behavior of aortic tissue was shown in
the 2 types of samples. Dissected tissue were stiffer than the intimal flap which was in
turn stiffer than non dissected tissue.
Histological data showed that in dissection group global elastin density was lower than in
control. Microstructural analysis in dissection specimens revealed a higher collagen signal
in the media mainly in circumferential plane, contrasting with a roughly similar intensity
between the two planes in control. This higher signal reflects higher collagen fiber density
and/or thicker fibers in this tunica.
Conclusion : Both in vivo and in vitro data revealed that dissected aorta was stiffer than
healthy ascending aorta. These findings has consequences on the choice of futur devices
dedicated to AA
;
Time Perspective: Prospective
| Status | Clinical Trial | Phase | |
|---|---|---|---|
| Recruiting |
NCT03894033 -
Post-market Registry of the AMDS for the Treatment of Acute DeBakey Type I Dissection
|