[Infrarenal abdominal aortic aneurysm: morphological classification as decision aid for therapeutic procedures].

This clinical trial aimed to prospectively investigate the morphological structure of infrarenal abdominal aortic aneurysms (AAA) to establish 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 anatomic AAA data must already be measured preprocedurally, due to the necessity for conversion as a frequent consequence of an intraprocedural failure. 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 classification system supporting the kind of the surgical procedure (standard) approach 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) neck < 15 mm, an infrarenal aortic diameter > 24 mm or an extension of the aneurysm to the iliac bifurcation are considered to be exclusion criteria for TPEG placement. In consideration of relevant co-morbidities (e.g. renal artery stenosis, SMA occlusion, iliac occlusive disease, simultaneous operations) only 43 out 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 consequence, indication criteria for AAA repair must not be expanded to smaller AAA.