PRELIMINARY CLINICAL OUTCOME AND IMAGING CRITERION FOR ENDOVASCULAR PROSTHESIS DEVELOPMENT IN HIGH-RISK PATIENTS WHO HAVE AORTOILIAC AND TRAUMATIC ARTERIAL LESIONS

Purpose: This report reviews our preliminary experience of prospective treatment of arterial lesions with endoluminal grafts in a Food and D rug Administration (FDA)-approved, investigator-sponsored Investigatio n Device Exemptions study. The utility and accuracy of various imaging methods, including angiography, cinefluoroscopy computed tomography ( CT), intravascular ultrasonography (IVUS), and duplex scanning, in per forming the procedures was also assessed. Methods: Thirty-one patients were evaluated; 17 patients were treated, including 11 with abdominal aortic aneurysms, one with an aortic occlusive lesion, two with iliac artery aneurysms, and three with traumatic arteriovenous fistulas. Tw elve of the 14 patients who had aorta and iliac artery lesions were hi gh-risk. The mean follow-up of patients treated was 9 months (range, 6 to 15 months). Results. Aortoaortic endoluminal interposition procedu res were not successful for treating abdominal aortic aneurysms early in the study (n = 3). Aortoiliac endoluminal bypass, contralateral ili ac artery occlusion, and femorofemoral bypass procedures were successf ul in seven of eight subsequent cases (88%), with no incidence of endo leaks at either the proximal or distal fixation sites using the deploy ment methods described in this report. The 30-day operative mortality rate on follow-up evaluations for patients who underwent aortoiliac pr ocedures was 14% (two of 14). Other major complications included trans ient renal failure in three patients that required short-term (two to eight times) dialysis, one arterial perforation and one dissection, an d one prolonged intubation. No myocardial. infarctions or strokes occu rred. After major complications or identification of limitations in th e study, the protocol was modified with the approval of the FDA to hel p avoid tile recurrence of the same problems. There were no deaths or complications in the trauma cases. Conclusions: Contrast-enhanced CT ( axial images and spiral reconstructions) was the most-accurate method to determine candidacy for aortoiliac procedures and to choose the sit e for deployment of the devices. Angiographic scans were misleading in several patients regarding the critical determinants of patient candi dacy and device deployment, particularly regarding the presence of a d istal aortic neck. Cinefluoroscopy wets used in all patients and was p articularly useful for determining the continuity of vascular structur es and the anatomy of branch arteries and for enabling precise positio ning of stent devices. Determination of fixation sites and assessing d imensional information by cinefluoroscopy and angiography were limited by inaccuracies produced by image magnification, parallax, and unipla nar views. IVUS was used to determine the morphologic features of vasc ular structures (i.e., calcium, thrombus), to perform real-time observ ation of the expansion of devices, and to assure firm fixation of ball oon-expanded stents before the procedures were completed, Duplex scann ing was very helpful in assessing and identifying precisely the locati on of arteriovenous fistulas before intervention and provided assessme nt at follow-up intervals. Three-dimensional reconstruction imaging te chnologies such as spiral CT were particularly helpful for assessing t he morphologic features of vascular anatomy before the intervention an d at follow-up intervals, whereas 3-D IVUS provided a similar real-tim e perspective during the procedure.