Sizing of the hybrid stent-graft for the frozen elephant trunk procedure

 Objective. The aim of study was to determine the tactics of choosing the optimal diameter of stent-graft in open hybrid repair of thoracic aorta based on the analysis of literature and the experience of Petrovsky National Research Centre of Surgery.

Material and Methods. A hybrid approach using the frozen elephant trunk (FET) technique is currently the safest and most optimal approach for thoracic aorta repair in case of extended pathology of all thoracic aorta segments, including the arch and descending thoracic aorta. Despite this technique has been used for over 15 years, there is no agreement in the current literature regarding the algorithm for choosing the optimal stent-graft diameter. A total of 135 FET procedures were performed at our centre from 2013 to 2020. The average age of patients was 52.8 ± 11.5 years. We analyzed our own experience and current literature to determine the optimal tactics for sizing the hybrid stent-graft for FET procedure.

Results. One of the main factors influencing the tactics of selecting the stent-graft diameter is the nature of pathology. The experience of most surgeons suggests that the size of stent-graft should not excessively exceed the diameter of a true canal in chronic dissection and the overall diameter in case of acute aortic dissection. In case of aneurysms, most authors use stent-grafts with the diameters exceeding distal landing zone diameter by 10–20%. Some authors consider it necessary to preoperatively measure the calculated diameter based on multislice computed tomography (CT) data, whereas many other authors prefer intraoperative measurements.

Conclusion. The use of a stent-graft, which is too large, can result in a high risk of new fenestration at the distal end level during the postoperative period and follow-up complications, whereas stent-graft, which is too small,  would not allow the adequate fit in the distal part. Therefore, the choice of optimal stent-graft size remains one of the key issues in hybrid thoracic aortic surgery. 

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