Hybrid thoracoabdominal aortic aneurysm repair: current perspectives

Abstract

Open repair of thoracoabdominal aortic aneurysms (TAAAs) is associated with significant morbidity and mortality. While open repair has remained the mainstay for treatment, this major surgical reconstruction is associated with a variety of complications due to the cardiopulmonary stress of this large-scale operation. Some of these complications include respiratory failure, heart failure, and acute renal failure, as well as spinal cord ischemia. With the progression of endovascular stent-graft technology, the development of a staged hybrid technique was first reported in the literature in 2004. The tenet of the hybrid approach is based on the reduced physiologic stress of operating through one visceral cavity rather than two (abdomen and thorax), which reduces complications and improves the ultimate outcome. This hybrid approach effectively "shifts" the proximal endovascular aortic repair landing zone away from a diseased paravisceral aorta to healthier proximal descending thoracic aorta by means of preceding open retrograde visceral bypass grafts. When thoracic endovascular aneurysm repair became available in 2005, there was much enthusiasm for this hybrid technique to extend the application for these patients with aneurysmal aorta in the paravisceral segment. However, subsequent reports have raised caution about the ultimate outcomes for this hybrid approach due to the major complications that still occur for these commonly infirmed patients. Instead, consideration of preoperative comorbidities, such as renal insufficiency, can influence outcomes. Review of the existing body of evidence identifies multiple small series describing these patients, but there is limited data of controlled trials or reasonable comparisons. We review some of the existing reports and provide our own experience with the hybrid technique of visceral debranching in preparation of a hybrid approach for thoracic endovascular aneurysm repair. We retrospectively evaluated our own experience evaluating hybrid repairs for TAAAs over a 5-year period. Between 2006 and 2010, 18 hybrid TAAA repairs were performed. Thirty-day mortality was 11.1%, with a 30-day visceral graft patency of 94.4%. One patient ruptured between visceral debranching and endovascular TAAA exclusion and is included as one of the two mortalities. Overall spinal cord ischemia occurred in 11.1% of hybrid TAAA repair patients. While fenestrated stent-graft technology continues to develop, the hybrid approach to TAAAs may reduce mortality as well as morbidity, particularly spinal cord ischemia, as supported by the current body of literature. The timing of each component of the staged approach remains to be standardized and long-term graft patency has not been established.