Computed tomography angiography-confirmed aortic in-stents floating thrombus after endovascular stenting: a retrospective study.

Background: Aortic in-stents floating thrombus (ASFT) is a rare complication. The evolution of ASFT on computed tomography angiography (CTA) imaging and the treatment options remain under investigations. The aim of this study was to analyze the imaging manifestations of ASFT on CTA, and to explore safe and effective treatment options. Methods: A retrospective, longitudinal study design was used. Clinical and imaging data were collected from patients with ASFT between January 2015 to December 2022 at the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. The imaging features of ASFT, including location, morphology, size, concomitant and dynamic changes during follow-up, were analyzed and classified into two types based on imaging manifestation. Type 1 showed a striated, irregular, or sheet-like appearance. Type 2 was a free-floating middle section in the cavity with attachment point to the thickened inner wall. The treatment protocol was also investigated. The Mann-Whitney U test was utilized for variable comparison. Results: A total of 1,626 cases were screened, out of which 10 cases were enrolled, resulting in an incidence rate of ASFT of 0.62% (10/1,626). The pre-surgery levels of fibrinogen (FIB), prothrombin time (PT), and D-dimer showed a higher trend, while only the D-dimer level increased significantly during the postoperative period (P<0.001). During the follow-up, CTA examination detected 21 ASFTs, including 18 ASFTs of type 1 and three ASFTs as type 2. One patient experienced spleen infarction when ASFT developed. During the follow-up period, thrombus disappeared in six patients, while the lesions remained stable in four patients. Renal infarction occurred in one case. No new-onset ASFTs or patient deaths were reported. Conclusions: ASFT is an extremely rare disease. The concomitant disorders and postoperative hemodynamic changes could be the cause. CTA examination presented as a safe and preferred imaging modality for evaluating the evolution and prognosis of ASFT. Conservative treatment may be a useful and effective option.