Postoperative Thrombus Detection within the FET Stent Graft

Background: Total aortic arch repair using the frozen elephant trunk (FET) procedure has become an effective and safe treatment for patients suffering aortic arch pathologies. Nevertheless we detected early thrombus formation within the stent graft of the FET-prosthesis. Our aim was to investigate the incidence and clinical relevance of postoperative in-stent thrombus formation following FET total arch replacement.

Method: Postoperative computed tomography angiography (CTA) scans of all 304 patients following the FET procedure between April 2014 and November 2021 were analyzed retrospectively. Thrombus size and location were assessed in multiplanar reconstruction using IMPAX EE (Agfa HealthCare N.V., Mortsel, Belgium) software. Patients' characteristics and clinical outcomes were evaluated between patients with and without thrombus formation.

Results: During the study period, we detected a new postoperative in-stent thrombus in 19 patients (6%). These patients were significantly older (p = 0.009), predominantly female (p = 0.002) and were more commonly treated for aortic aneurysms (p = 0.001). In 15 patients (79%), the thrombi were located in the distal half of the FET stent graft. Thrombus size was 18.9 mm (first quartile: 12.1; third quartile: 33.2). Distal embolization occurred in 4 patients (21%) causing one in-hospital death caused by severe visceral ischemia. Therapeutic anticoagulation was initiated in all patients. Overstenting with a conventional stent graft placed within the FET stent graft was the treatment in two patients (11%). Female sex (p = 0.005; OR: 4.289) and an aortic aneurysm (p = 0.023; OR: 5.198) were identified as significant predictors for thrombus development.

Conclusion: Postoperative new thrombus formation within the FET stent graft is a new, rare, but clinically highly relevant event. Female gender and patients suffering from aortic aneurysms seem to be at higher risk for new in-stent thrombus formation. The embolization of these thrombi can result in dismal postoperative outcomes. Our findings also show the importance of postoperative follow-up visits of our patients. Additional research is required to better identify patients at risk and improve peri- and postoperative treatment.

Publication History

Article published online:
28 January 2023