Title: The Fate of the Distal Aorta After Repair of Acute Type A Aortic Dissection
Abstract: Conclusions: Expansion of the distal aorta after repair for acute type A aortic dissection is linear and slow, with a low risk of distal reoperation. The risk of death is twice that of a healthy population. Summary: The natural history of the distal aorta in patients with acute type A aortic dissection is not fully understood. The authors analyzed factors influencing long-term survival, operation of the distal remaining aorta, and segmental growth rates of the distal aorta after successful repair of acute type A aortic dissection. Between 1986 and 2003, 176 consecutive patients (70% male) with a mean age of 60 years underwent repair of acute type A aortic dissection using an open distal anastomotic technique with resection of intimal tear. Patients had follow-up computed tomography scans with digitalization of distal aortic segments and calculation of segment-specific growth rates of the distal aorta. Factors influencing faster growth were analyzed, and patient survival and the incidence of distal reoperation were also determined. A total of 89 patients (57%) had sufficient imaging data for calculations of serial growth rates. After repair of the acute type A aortic dissection, the median diameters of the aorta were aortic arch, 3.6 cm; descending aorta, 3.7 cm; and abdominal aorta, 3.2 cm. Respective growth rates were 0.8, 1.0, and 0.8 mm/y. Greater growth rate in the descending aorta was predicted by an initial size of >4 cm (P = .005) and by diameters of <4 cm with a patent false lumen (P = .004). Male sex significantly affected growth rate in the abdominal aorta (P = .05). Sixteen patients had a distal aortic reoperation (n = 25). The risk of reoperation was 16% at 10 years. Survival after repair of acute type A aortic dissection was influenced by age (P < .0001), neurologic deficit at time of presentation (P = .04), lack of preoperative thrombus in the false lumen of the ascending aorta (P = .03), and a patent distal false lumen postoperatively (P = .06). The site of the operation did not influence long-term survival. Comment: The data regarding expansion rates of the residual aorta after acute type A dissection repair should be viewed with some caution. Only 57% of survivors had sufficient imaging data for calculation of late growth rates. There may have been patients with accelerated growth rates or aortic complications secondary to an accelerated growth rate who were not included in this study. It is probably best to regard the growth rates presented here as “ballpark” figures.