INFRARENAL ABDOMINAL AORTIC-ANEURYSM (AAA ) - MORPHOLOGICAL CLASSIFICATION AS FOR SUPPORTING EITHER CLASSICAL OR ENDOVASCULAR APPROACH

This clinical trial aimed to prospectively investigate the morphologic al structure of infrarenal abdominal aortic aneuryms (AAA) to establis h a valid dataset in the preoperative assessment supporting either the conventional or endovascular (TPEG) surgical approach. Regarding both the general feasibility testing and safe TPEG placing, all the anatom ic AAA data must already be measured preprocedurally, due to the neces sity for conversion as a frequent consequence of an intraprocedural fa ilure. Between January 1993 and June 1995, all the patients (n = 159) admitted for elective AAA repair, were prospectively analysed. Graded on the basis of these measurements we developed a new AAA classificati on system supporting the kind of the surgical procedure (standard appr oach vs. TPEG). Three different types of AAA were clearly defined. Due to morphological AAA criteria, 86 out of 159 patients (54.1 %) might be suitable for TPEG (Type I, IIA and IIB). An infrarenal (proximal) n eck <15 mm, an infrarenal aortic diameter >24 mm or an extension of th e aneurysm to the iliac bifurcation are considered to be exclusion cri teria for TPEG placement. In consideration of relevant co-morbidities (e.g. renal artery stenosis, SMA occlusion, iliac occlusive disease, s imultaneous operations) only 43 out of 159 patients (27.1 %) were good candidates for TPEG. In general, smaller AAA are more appropriate for TPEG repair due to better proximal and distal fixation. As a conseque nce, indication criteria for AAA repair must not be expanded to smalle r AAA.