Discussion

Dr Steven Rivers (Bronx, NY): I have been intrigued and impressed with the absence of spinal cord ischemia in the TEVAR patients and in several other reports of similar endovascular treatment of thoracic aneurysms. It makes me wonder if for the patients that we still need to do open repairs on, are we wasting our time doing intercostal reimplantations? Are we wasting our time with spinal cord fluid measurements and various other procedures that we have been doing to alleviate some of the problems with open repair? But particularly, intuitively, we have always reimplanted as many of these vessels as we can and, I mean, are we wasting our time? And also, could you comment on whether or not there were any specific protocols for your open repair techniques.

Dr Jon S. Matsumura: The incidence of paraplegia is not zero with TEVAR. It does occur, and paraparesis with partial weakness also occurs after TEVAR. However, it is my impression that it is less frequent than in open repair. Nevertheless, we use adjuncts per institutional protocol. In this trial, 26% of the TEVAR patients had a spinal drain placed, and most institutions keep the mean arterial pressure elevated.

With TEVAR, one cannot reimplant the intercostal vessels, but one does have to decide on what to do when covering the left subclavian artery, which provides the upper cord with some collateral supply. Unlike a previous trial, we did not have a policy to routinely revascularize the subclavian artery if it was covered in this trial. In my own center, it is a routine practice to do it. Based on EuroSTAR [European Collaborators on Stent/Graft Techniques for Aortic Aneurysm Repair] data presented earlier, many centers may begin to make that a routine practice. If subclavian revascularization is helpful in TEVAR, that suggests that we are not wasting our time with intercostal reimplantation with open repair.

The open repair techniques in this trial were also per institutional protocol and not standardized, other than we excluded planned deep hypothermic circulatory arrest. About 80% had spinal cord protection, and that included epidural cooling, spinal cord drainage, and distal perfusion in the majority of patients.

Dr Amy Reed (Cincinnati, Ohio): Could you share with us just what you are doing for a preoperative evaluation of the carotids and vertebrals. Are you just doing a carotid duplex or CT angiography or anything specific to try and pick out those patients that might have problems with stroke postoperatively?

Dr Matsumura: The reality is most TEVAR patients have a CTA or MRA that images the aortic arch and most of the proximal carotid and vertebral circulation. Inspecting the arch and carefully selecting patients is probably important in preventing stroke with TEVAR, similar to preventing stroke with transfemoral carotid stenting. Based on my own experience, and that of some expert colleagues in this room, if you are going to electively cover the left subclavian with TEVAR, you should revascularize it. Our favorite method is a transposition, unless they have an internal mammary artery attached to a coronary artery, in which case we do a carotid–subclavian bypass. If you do subclavian revascularization routinely, there is not much benefit to image the distal vertebral or basilar arteries.

If one practices selective revascularization, I strongly recommend imaging both vertebral arteries and the intracranial circulation. There will be a few patients with abnormalities that will influence how the left vertebral or left subclavian are treated.