Fate of remaining dissected aorta after descending thoracic or thoracoabdominal aorta replacement for chronic dissection.

Objectives: After performing descending thoracic or thoraco-abdominal aorta replacement for chronic aortic dissection, the fate of the remaining dissected aorta, without significant enlargement, is not well known. This study aimed to investigate the changes in the remaining aorta and the risk factors for late composite aortic events.

Methods: In 98 patients with chronic type A or B aortic dissection who underwent descending thoracic or thoraco-abdominal aorta replacement, the immediate postoperative and last follow-up computed tomography scans were reviewed. Aortic area-derived diameter was measured using the centreline reconstruction method at the levels of the 10 zones of the aorta and iliac arteries. The incidence of and risk factors for late composite aortic events (aortic death, rupture, reoperation, last follow-up aortic area-derived diameter >60 mm) were analysed.

Results: The median follow-up and computed tomography follow-up durations were 88.5 and 63.7 months, respectively. Nine late deaths occurred. The median growth rate of the remaining aorta was the greatest in the dissected infrarenal abdominal aorta at 0.8 mm/year. Of 16 late composite aortic events, the majority (2 ruptures and 8 reoperations) occurred in the distal contiguous segment. The 5- and 10-year cumulative incidence of events in the distal contiguous segment were 4.9% and 16.1%, respectively. Young age and Marfan syndrome were significant risk factors.

Conclusions: Late composite aortic events were not negligible, especially in the distal contiguous segment. In young or Marfan syndrome patients, a greater distal extent of replacement may have to be considered at experienced aortic centres.