Endovascular repair of thoracoabdominal aneurysms: design options, device construct, patient selection and...

The aim of this paper was to describe the current status of endovascular thoracoabdominal aortic aneurysm (TAAA) repair. This is a comparative review of current device designs and implantation techniques. A literature review of all reported results of endovascular TAAA repair has also been carried out, together with a comparison of clinical outcomes achieved with endovascular TAAA repair and those achieved in current series of standard open TAAA repair. Endovascular TAAA repair has been performed with both unibody and modular devices, but modular devices currently predominate. In modular devices the aortic component provides access to the target visceral artery either through a fenestration or a cuff. Cuffs increase device profile and the length of aorta that is covered, but easily accommodate variations in deployment position and provide a good seal zone. Fenestrations do not affect device profile or add length to the device, but deployment position tolerates little deviation and the seal zone is tenuous. A covered stent is used to bridge the gap between the fenestration or cuff in the aortic component and the target visceral artery. Balloon-expandable covered stent branch extensions are delivered from the femoral approach when fenestrations are used. Self-expanding covered stents are delivered from either the brachial or femoral approach when cuffs are used, depending on the orientation of the cuff. Some groups reinforce the self-expanding covered stent with an uncovered self-expanding stent to enhance flexibility and stability. The majority of endovascular TAAA repairs have been performed in three centers, accounting for 84% of all reported cases. The treated TAAAs were Type 1 31.8%, Type 2 14.2%, Type 3 14.2% and Type 4 37.5%. Perioperative mortality is 6.9% (N. = 20), late mortality 13.6% (N. = 38), spinal cord ischemia (SCI) 14.9% (N. = 29) permanent in 6.7% (N. = 6), transient in 10.0% (N. = 9). Deterioration of renal function was reported in 9.8% (N. = 8), and required initiation of dialysis in 5.1% (N. = 5). Reintervention was required in 18 patients (20.0%) early in 8.9% and late in 11.1%. Branch occlusion developed in 3.5% (N. = 9) and stenosis in 0.85% (N. = 2). Current single-center series of open surgical TAAA repair report mortality rates of 5-16%, spinal cord ischemia rates of 3.8-15.5% and new onset dialysis between 2-16.2%. Population-based series of open surgical TAAA repair report mortality rates between 19.2-26.9%, spinal cord ischemia rates between 7.3-16.0% and new onset dialysis rates of 14.2-18.2%. Final status of SCI neurologic deficit, reintervention rates and branch occlusion or stenosis rates for open TAAA repair are inconsistently available, if at all. In conclusion, endovascular TAAA repair is an evolving technique that is developing increasing consistency in device design and implantation technique. It is effective in eliminating aneurysm flow and in preserving visceral branch perfusion. These early outcomes are better than the results achieved with open TAAA repair in population-based studies and are at least equal to the results of open TAAA repair reported from centers of focused expertise. These results support expanding the indications for endovascular TAAA repair to include standard risk patients.