Simplified elephant trunk technique promotes thrombo-occlusion of the false lumen in acute type A aortic dissection

We developed a "simplified elephant trunk (SET) graft technique" as a refinement of the original elephant trunk. A cuff is created in a single 4-branched graft, which is used for the distal anastomosis; the residual distal graft is used as the trunk. We expected the SET would secure the anastomosis and promote the thrombo-occlusion of the false lumen in the down stream of the aorta. In this paper, we highlight the usage of the SET for arch replacement of acute aortic dissection cases in comparison with the same arch replacement without the SET method.

Between March 1996 and March 2002, 35 patients underwent arch replacement for acute aortic dissection. Twenty-two of them had a patent false lumen in the downstream aorta at the operation and 17 (SET: 8, non-SET (NSET) : 9) out of 22 underwent enhanced computed tomography (CT) scan 2 weeks after and 1 year after operation. We calculated the ratio of the false lumen in the aorta (F ratio) and the ratio of the patent false lumen in the whole false lumen (E ratio) by CT scan. These values were calculated every 3 cm down to 15 cm below the anastomosis, thus resulting in 5 segments.

The false lumen throughout all segments disappeared (F ratio =0) in none of both group 2 weeks after operation. One year thereafter, in 5 (63%) patients in the SET group, no false lumen in any segment existed, while in contrast a false lumen still existed in some of the segments in all NSET patients. Although neither the F and E ratio of the NSET group change during this period in any segments, those of the SET group decreased significantly in all the segments except for the E ratio of segment 5.

The SET promoted thrombo-occlusion thus leading to the disappearance of the residual false lumen, possibly by avoiding persistent endoleakage at the anastomotic site.