The impact of entries and exits on false lumen thrombosis and aortic remodelling.

OBJECTIVES: In DeBakey Type I acute aortic dissection, the frozen elephant trunk technique is used for the combined treatment of both the proximal and distal thoracic aorta. Anatomical characteristics of the distal aorta and their impact on false lumen (FL) thrombosis and aortic remodelling were analysed in this study.

METHODS: Sufficient pre-, postoperative, and at least one 1-year follow-up computed tomography data sets were available for 63 of 94 patients treated with the frozen elephant trunk for Type I acute aortic dissection between March 2005 and March 2015. Aortic remodelling and FL thrombosis quotients were calculated volumetrically at the stent graft level (A), from A to the coeliac trunk (B) and from B to the bifurcation (C) and were correlated with the number and size of entry tears and aortic branches arising from the FL (exits) in each segment.

RESULTS: Positive or stable remodelling was found in Segments A (94%), B (64%) and C (54%), and the FL thrombosis quotient was 98% in A, 68% in B and 39% in C within the first year. FL thrombosis correlated negatively with the total size of the entry (P<0.001) and the number of exits (P<0.001) and positively with the number of true-lumen branches (P<0.001). The exit number was a risk factor for FL patency and a predictor of negative remodelling.

CONCLUSIONS: Using frozen elephant trunk technique to treat Type I acute aortic dissection facilitates positive or stable remodelling in nearly all patients at the stent graft level and distally in two-thirds of the patients. FL thrombosis and aortic remodelling are negatively influenced by the number of exits. New endovascular concepts aiming at reducing the number of exits may prevent negative remodelling.