[Endovascular aneurysm treatment: Radiological and macropathological findings of the endoluminal surface of modular stent grafts].
OBJECTIVE
Characterization of the endoluminal surface of a modular stent graft and correlation of macropathological findings with results of radiological methods.


METHODS
Aneurysms of the infrarenal aorta were created in 36 mongrel FBI dogs using autologous material. Endovascular treatment was performed with modular stent grafts using two polyester-covered nitinol stents connected with overlap within the aneurysm. Follow-up was 1 and 6 weeks, and 6 months for 12 animals, respectively. Results were documented using sonography, intravascular ultrasound (IVUS), spiral CT, MRI, and digital subtraction angiography (DSA). After fixation, the aorta was prepared and incised lengthwise. Before histopathological work-up, the different segments were macropathologically characterized and correlated with the respective findings of the radiological methods.


RESULTS
4 cases showed high grade stenosis within the stent grafts and graft occlusion occurred in two cases. The connection sites of these modular stent grafts showed steps and partial separation of the graft components was causative in 5 of these cases. Migration of graft components occurred in three cases, one of them with complete disconnection of the modular device. Irregulartities and deposits on the endoluminal surface were systematically underestimated with all radiological techniques used. IVUS showed moderate concordance concerning deployment and unfolding of the stent graft, however, irregularities of the endoluminal surface were systematically underestimated. Concordance of MRI, sonography, and CT was worse. Contrast-enhanced T1-w MRI detected endoluminal deposits with moderate concordance. However, the thickness of deposits was underestimated. DSA, IVUS, and CT showed only poor concordance with macropathological findings.


CONCLUSIONS
The connection site of modular stent grafts predisposes to stenosis, occlusion, and disconnection of the modular device. Stent deployment and unfolding of the membrane might be examined with IVUS. MRI is useful for detecting endoluminal deposits and stenosis. However, radiological methods will underrate irregularities and deposits of the endoluminal surface.
Pitton
M B
MB
Klinik für Radiologie, Universitätskliniken, Langenbeckstrasse, Mainz, Germany.
Hillebrand
J
J
Schmenger
P
P
Düber
C
C
Neufang
A
A
Konerding
M A
MA
Krummenauer
F
F
Thelen
M
M
D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D004195:Disease Models, Animal; D004285:Dogs; D006801:Humans; D011474:Prosthesis Design; D011859:Radiography; D015607:Stents; D016896:Treatment Outcome