Treatment of Aortic Arch Diseases.

Aortic aneurysm formation is a well-documented complication in patients with coarctation of the aorta, whether untreated or treated.Patients not undergoing surgical or interventional treatment may develop aneurysms of the ascending aorta, possibly involving the aortic arch. This is prob- ably the manifestation of inherent aortic wall abnor- malities.A bicuspid aortic valve (present in 85% of these pa- tients) is well known to be associated with aorticpa- thology and has been confirmed as an independent predictor of ascending aortic aneurysm in this patient population.Moreover, coarctation patients typically have proximal arterial hypertension, which causes increased haemo- dynamic stress on the aortic wall and predisposes to aneurysm formation, rupture and aortic dissection.As a result, approximately 20% of adults with coarcta- tion will die from spontaneous rupture of the aorta if left untreated.Close supervision of patients with bicuspid aortic valves and ascending aortic dilatation is mandatory to prevent such catastrophic complications.Patients who have undergone surgical repair may also develop postoperative aneurysms in the region of the aortic isthmus.These aneurysms are usually asymp- tomatic but are associated with a 36%mortality rate if left untreated.They can be true or false and may in- volve the distal aortic arch.Their incidence varies and depends on a number of factors, i.e. the time of operation, age at the time of surgery, the postoperative interval and the surgical technique employed.Although all types of surgical repair have the risk of aneurysm formation, prosthetic Dacron patch aorto- plasty has been historically associated with the highest incidence (up to 39%) of this complication.In the initial descriptions of the procedure, the posteri- or coarctation membrane or fibrous shelf was excised. This manoeuvre was later found to be a significant predisposing factor for development of true aneu- rysms and it is now discouraged. It also appears that the risk of aneurysm formation is higher for patients operated on at >13.5 years of age, for patch aortoplasty of recoarctation following resection with end-to-end anastomosis, and for patients with coarctation associ- ated with transverse arch hypoplasia.Recent series using PTFE for the patch have not re- ported any aneurysm in a short follow-up period.Aneurysm formation also complicates balloon angio- plasty. Disruption of the intima and morphologically distorted elastic media in the precoarctation and post- coarctation aortic segments are probably causally con- nected with this complication.Dilatation of native adult coarctation is particularly associated with aneurysm formation, the reported incidence varying from 4% to 42%. As a result, most centres do not routinely utilize angioplasty in the management of native coarctation. Aneurysms may develop either immediately after angioplasty or after several months, hence close follow-up is essential. On the other hand, balloon angioplasty may be the pre- ferred approach for recurrent coarctation following surgical repair.Due to the apparent protective effect of the fibrous perivascular surgical scar, aneurysm formation is a rather infrequent complication (0-5%)in this setting. [ABSTRACT FROM AUTHOR]