The Fate of Infrarenal Abdominal Aortic Aneurysms After Stent Grafting

Abstract

To evaluate the effect of postoperative thrombosis of the side branch ostia on the shrinkage of endoluminally treated abdominal aortic aneurysms with patent side branch vessels. Thirty-three patients were followed up with serial computed tomography (CT). Special attention was paid to presence or absence of retrograde enhancement of the side branch ostia after the covering of the patent side branch vessels by the stent graft and aneurysm diameter change on postoperative CT. Preoperative CT was also reviewed to assess the number of patent side branch vessels, degree of aneurysm wall calcification, and thickness of the mural thrombus. The patients with type 2 endoleak were excluded from this evaluation. The patients were divided into 2 groups, the nonthrombosed and thrombosed groups, based on presence or absence of retrograde enhancement of the side branch ostia as depicted on all postoperative CT. Type 1 endoleak was not seen in all patients. Preoperative diameter of the aneurysm was 4.75 +/- 0.18 cm in the thrombosed group (n = 12) and 4.98 +/- 0.35 cm in the nonthrombosed group (n = 8). There were no significant differences in follow-up periods, preoperative diameter of the aneurysm, number of patent side branch vessels, degrees of aneurysm wall calcification, and thickness of the mural thrombus between the 2 groups. The mean diameter of the aneurysm in the nonthrombosed group did not change at 3 and 6 months then first decreased at 12 months after the stent grafting. However, in the thrombosed group, the mean diameter of the aneurysm had decreased at 3 months after stent grafting. Thereafter, the aneurysms continuously shrank. Postoperative thrombosis of the side branch ostia may predict favorable shrinkage of endoluminally treated aneurysms.