[Transluminal treatment in aneurysm of the abdominal aorta. Role of diagnostic imaging].

Purpose: To emphasize the importance of diagnostic imaging: a) in the selection of patients to be treated with the transluminal approach b) during stent-graft positioning c) in the follow-up of treated patients.

Material And Methods: From January 1997 to May 1998, twenty-five patients with abdominal aortic aneurysms (AAA) were treated with transfemoral stent-grafts (AneuRx Medtronic). All patients were submitted to a preoperative study including digital angiography (DSA) and Spiral CT. Intraoperatively they underwent DSA and intravascular ultrasound (IVUS). Follow-up was performed with Spiral CT.

Results: Twenty-four bifurcated and one straight device were inserted in twenty-five patients with AAA. In two cases it was impossible to position the endoprosthesis due to narrow or tortuous artery access. Following the intention to treat criteria, the technical success rate was 92.5%. All the stents were patent and no dislodgement was observed at follow-up. Partial thrombosis of the stent was observed in three patients. Owing to incomplete distal covering, early endoleak occurred in one patient with an aortoiliac aneurysm; the positioning of two cuffs allowed a successful outcome. CT examination performed 6 months after positioning revealed the presence of endoleaks in three patients, due to persistence of lumbar and inferior mesenteric artery patency. The AAA was no more appreciable in five of the ten patients submitted to CT follow-up one year after the procedure. In three of ten cases it was reduced in size and in two patients there was no change.

Discussion: Spiral CT plays a basic role in the selection of patients because it helps assess the length and diameter of the proximal neck, thus permitting to choose the device to be inserted. Preoperative DSA is mandatory in the evaluation of size and tortuosity of the iliac arteries. IVUS allows to monitor the site of delivery during the maneuver and to make the final measurements while DSA plays a role in checking the correct positioning of the device and excluding the presence of endoleaks at the end of the procedure. Late follow-up with Spiral CT aims at demonstrating possible malfunctioning of the endoprosthesis and confirms the definitive exclusion of AAA.

Conclusions: Diagnostic imaging plays a basic role in the endovascular treatment of AAA, much more than that required for traditional surgical treatment. In particular, pretreatment planning is critical and requires sophisticated imaging including Spiral CT with 3D reconstruction and angiographic evaluation using catheters with calibrated markers.