IntroductionThe increase in endovascular treatment of abdominal aortic aneurysms has led to seeing more complications, such as intraprosthesis thrombus formation, which is not without risk. ObjectivesTo determine the incidence of mural thrombus and the clinical course, and the factors that can directly influence its development. Material and methodsA retrospective review (July 2006-October 2011) was conducted on patients with endovascular repair of abdominal aortic aneurysms, who were monitored with computed tomographic angiography for more than 6 months. A study was made of the appearance of mural thrombus in relation to the endograft characteristics (type, material, length, ratio [R2/ (r12+r22)] and internal iliac artery patency) using contingency tables, ANOVA test, and logistic regression. ResultsA total of 63 cases were found, with an average follow-up of 17.43 months. The incidence of mural thrombus recorded was 22.2% (14), of which 78.6% (11) developed in the first month, and 21.4% (3) in the following 6 months. There was a higher incidence with Excluder® (7 of 18 [28%]) and Zenith® (5 of 8 [62.5%]) (P=.010), being the ratio the only predictor of thrombus formation, in both bivariate analysis (P=.001; 95% confidence interval from 0.392 to 1.453) and logistic regression (P=.021; odds ratio 3.424; 95% CI 1.205 to 9.727). There were no cases of thrombus recurrence. Only one case progressed to branch thrombosis in 17 months of follow-up, which did not require additional intervention. ConclusionsIntra-prosthetic mural thrombus is commonly found after endovascular abdominal aortic aneurysms repair, being more associated to other types of endografts. Finding a major discrepancy area may be useful as a predictor. For early detection of thrombus, we recommend a closer monitoring with computed tomographic angiography.