[Retrograde type A dissection after endovascular stent grafting of type B dissection]

Acute aortic dissection is a disease with high mortality. Whereas acute dissection of the ascending aorta (Standford type A) is treated surgically, acute dissection of Stanford type B (descending aorta) is principally treated conservatively, but surgically in case of complications. Recently, another therapeutical option for the treatment of type B dissection has been developed using endovascular stent-grafts. We report on a 64-year-old woman with typical signs of acute aortic dissection. Computer tomography and transesophageal echocardiography demonstrated Stanford type B dissection. The patient was treated with an endovascular stent-graft, because of malperfusion of the right leg and chest pain. After successful closure of the entry by the stent, the patient developed acute right-sided hemiplegia one day after the intervention due to retrograde dissection into the aortic arch and ascending aorta. Upon immediate operation, the origin of the initially type B dissection was still sufficiently occluded by the endovascular stent-graft; however, there was another entry between the innominate artery and the left carotic artery near one proximal end of the stent's strut. Using deep hypothermia and selective antegrade cerebral perfusion, the ascending aorta and proximal arch were replaced with a 28 mm Dacron-Velour tube and the aortic root was remodelled with a tongue-shaped Dacron graft preserving the valve cusps according to a modified Yacoub procedure. After the operation, neurological symptoms diminished and the patient could walk on the ward on day eleven. This case demonstrates retrograde type A dissection as a complication after interventional treatment of type B dissection using an endovascular stent-graft. The reason for this delayed complication is speculative. Aortic wall damage during stent inserting could be a possible cause. It is also likely that the patient initially had type B dissection with retrograde dissection of the distal part of the aortic arch. Therefore, one of the straight struts of the proximal end of the stent may have caused additional damage to the vulnerable dissected aortic wall in the arch, leading to retrograde type A dissection. Careful patient selection, detailed diagnosis of the aortic arch, improved stent designs and materials, especially regarding the stent's ends and careful insertion of the stent into the aortic arch, could contribute to prevention of the described problems.