Surgical strategies in the management of chronic dissection of the thoracoabdominal aorta.

Abstract

Most operations for dissection of the thoracoabdominal aorta take place in the chronic phase of the disease, because the acutely dissected distal aorta is almost always initially treated non-surgically with aggressive pharmacological anti-impulse therapy. Identifying patients who are no longer responding to medical treatment is the first step in preventing further disease progression and rupture. Symptomatic aneurysms should be promptly repaired. Asymptomatic patients are followed until significant aortic dilation occurs and reaches a threshold of intervention: current guidelines endorse repair once a diameter of 5.5 cm is reached. In patients with heritable thoracic aortic disease (such as Marfan Syndrome), the threshold of intervention is often lowered. Aortic replacement typically centers on the dilatated segment. For all extents of repair, we use passive mild hypothermia, sequential aortic cross-clamping, aggressive reimplantation of intercostal and lumbar arteries, and cold renal perfusion whenever possible. For Crawford extents I and II thoracoabdominal aneurysm repair, we routinely use cerebrospinal fluid drainage, left heart bypass, and selective visceral perfusion. A four-branched graft approach to thoracoabdominal aortic aneurysm repair is frequently used in patients with chronic aortic dissection; this approach facilitates visceral artery perfusion during repair, expedites the distal anastomosis, and prevents subsequent visceral patch aneurysms. Lifelong imaging surveillance is necessary, because the distal aorta often continues to expand; residual aortic dissection commonly remains after repair and may necessitate further repair.