Natural history of periprosthetic air on computerized axial tomographic examination of the abdomen following abdominal aortic aneurysm repair.

The presence of periprosthetic gas on computerized axial tomography (CT) of the abdomen following abdominal aortic reconstruction has been proposed to be a reliable indicator of prosthetic graft infection, a complication that requires intervention entailing significant mortality and morbidity. To evaluate the reliability of this finding in the early postoperative period, prosthetic grafts in 26 patients undergoing elective aneurysm repair were evaluated with postoperative CT examinations. Serial scans were obtained at mean intervals of 3, 7, and 52 days postoperatively. The presence or absence of periprosthetic air on CT scan was noted, and the results were correlated with aneurysm size as determined by preoperative ultrasound examination of the abdominal aorta or by measurements made during operation. Mean aneurysm size was 6.1 cm (range 4.5 to 10.6 cm). Periprosthetic air was demonstrated in 17 (65%) of the 26 patients studied within 1 week postoperatively. Patients with aneurysms larger than 6.0 cm were more likely to demonstrate periprosthetic air then those with smaller aneurysms (chi 2 = 5.024, p = 0.025). All patients found to have periprosthetic air had spontaneous resolution by late CT scanning obtained a mean of 52 days postoperatively (range 21 to 85 days). One patient died in the early postoperative period and two did not return for late scans. Only one patient demonstrated periprosthetic air as late as the thirty-second postoperative day, and this air had resolved by the seventieth postoperative day.(ABSTRACT TRUNCATED AT 250 WORDS)