Are Improved Results for Hybrid Repair of Thoracoabdominal Aortic Aneurysms Due to a Learning Curve or Better Patient Selection?

Abstract

pen repair of thoracoabdominal aortic aneurysms (TAAAs) has traditionally been accompanied by significant morbidity and mortality. The use of adjuncts such as hypothermia and selective visceral perfusion has decreased the rates of permanent paraplegia to Ͻ5%, renal failure requiring dialysis to Ͻ5%, and 30-day mortality to Ͻ10% when performed in high-volume centers of excellence. 1,2 However, when this operation is applied across a broad spectrum of institutions, the overall morbidity and mortality can be significantly higher. One statewide registry reported a 1-year mortality rate of 40% when TAAA repair was performed in patients Ͼ75 years of age. 3 In addition, there exists a subset of patients who are considered too high risk for open repair, usually because of the severity of their underlying pulmonary disease and other medical comorbidities. 4 Article see p 2670Thus, vascular interventionalists have searched for less morbid ways to treat these complex patients. The use of thoracic endografts has been demonstrated to decrease the overall morbidity and mortality of patients undergoing repair of both elective and emergent thoracic aortic pathology. 5,6 However, the availability of branched endografts to treat TAAAs involving the visceral vessels has been limited, particularly in the United States. 7,8 Thus, the concept of combining a lesser open abdominal operation to bypass the visceral and renal vessels with the placement of an endovascular stent graft in the descending thoracic aorta has been developed as a hybrid open endovascular technique. As Moulakakis et al 9 point out in this issue of Circulation, no prospective randomized trials have compared hybrid open endovascular technique procedures with standard open TAAA repair, repair using branched endovascular grafts, or even best medical therapy. Current results from multiple single-center series describe a wide range of morbidity and mortality.Moulakakis et al 9 performed a meta-analysis of 19 series published over the past decade describing the results of hybrid TAAA repair in 507 patients. Despite the wide range of outcomes, the pooled estimates for 30-day mortality of 12.8% (95% confidence interval, 8.6 to 17), for irreversible paraplegia of 4.5% (95% confidence interval, 2.5 to 7.0), and for renal impairment requiring dialysis of 8.8% (95% confidence interval, 3.9 to 15.5) seem to provide a realistic expectation of potential outcomes in this high-risk group of patients. 9 We reported a slightly higher 30-day mortality of 17.4% with a comparable paraplegia rate of 4.3% and rates of renal insufficiency similar to that of open repair in a series of 23 high-risk patients undergoing debranching procedures. 4 However, the in-hospital mortality of 26% in our series and 1-year mortality of 32% provide a sobering perspective on the potential long-term risks of hybrid intervention in these patients. These outcomes have certainly caused us to apply this strategy conservatively in patients deemed unfit for open TAAA repair.On the other hand, several institutions ...