Features and risk factors of early intraluminal thrombus formation within the frozen elephant trunk stent graft.

Objective: The frozen elephant trunk is a standard treatment method for aortic arch pathologies extending into the descending aorta. We previously described the phenomenon of early postoperative intraluminal thrombosis within the frozen elephant trunk. We investigated the features and predictors of intraluminal thrombosis.

Methods: A total of 281 patients (66% male, mean age 60 ± 12 years) underwent frozen elephant trunk implantation between May 2010 and November 2019. In 268 patients (95%), early postoperative computed tomography angiography was available to assess intraluminal thrombosis.

Results: The incidence of intraluminal thrombosis after frozen elephant trunk implantation was 8.2%. Intraluminal thrombosis was diagnosed early after the procedure (4.6 ± 2.9 days) and could be successfully treated with anticoagulation in 55% of patients. A total of 27% developed embolic complications. Mortality (27% vs 11%, P = .044) and morbidity were significantly higher in patients with intraluminal thrombosis. Our data showed a significant association of intraluminal thrombosis with prothrombotic medical conditions and anatomic slow flow features. The incidence of heparin-induced thrombopenia was higher in patients with intraluminal thrombosis (18% vs 3.3%, P = .011). Stent-graft diameter index, anticipated endoleak Ib, and degenerative aneurysm were significant independent predictors of intraluminal thrombosis. Therapeutic anticoagulation was a protective factor. Glomerular filtration rate, extracorporeal circulation time, postoperative rethoracotomy, and intraluminal thrombosis (odds ratio, 3.19, P = .047) were independent predictors of perioperative mortality.

Conclusions: Intraluminal thrombosis is an underrecognized complication after frozen elephant trunk implantation. In patients with risk factors of intraluminal thrombosis indication for frozen elephant trunk should be carefully evaluated and postoperative anticoagulation considered. Early thoracic endovascular aortic repair extension should be considered in patients with intraluminal thrombosis to prevent embolic complications. Stent-graft designs should be improved to prevent intraluminal thrombosis after frozen elephant trunk implantation.