Thoracoabdominal Aneurysm Repair: An All Endo Approach

BY MARK S. LESNEY

Results of a small study using multibranched stent-graft implantation for thoracoabdominal aneurysm repair showed benefits indicating this technique should have an expanded role in treatment, according to Dr. Timothy A. M. Chuter.

Self-expanding covered stents were used to connect the caudally directed cuffs of an aortic stent graft with the visceral branches of an aortic aneurysm in 16 patients, according to Dr. Chuter in an interview regarding the study he and his colleagues from the University of California, San Francisco, and the Cook Australia Research Laboratory, Perth, presented at the Vascular Annual Meeting.

The 11 men and 5 women were all considered unfit for open repair. Prior aortic surgery had been undergone by seven of the patients.

The procedure was performed totally endovascularly in each case. The customized aortic stent grafts were inserted through surgically exposed femoral (12 patients) or iliac (4 patients) arteries. The covered stents were all inserted through surgically exposed brachial arteries. In all 16 cases, spinal catheters were used for cerebrospinal fluid pressure monitoring, and additionally for spinal anesthesia in 10 patients; the other 6 had general anesthesia, according to Dr. Chuter.

Follow-up included contrast-enhanced CT scans at 1 week and at 1, 6, and 12 months.

In all 16 patients, the stent grafts were successfully deployed and covered an average of 78% of total aortic length from the subclavian orifice to the bifurcation, involving 57 visceral branches, Dr. Chuter stated.

Significant perioperative complications developed in four (25%) of the patients. These included two patients, both with severe, long-standing chronic obstructive pulmonary disease, who developed pneumonia.

One patient developed paraplegia and renal failure, and died after refusing dialysis; and one patient underwent successful reintervention for iatrogenic aortic dissection and type 1 endoleak. There were no strokes, myocardial infarctions, other deaths, complications, endoleaks, or reinterventions, Dr. Chuter reported.

Two patients did experience transient lower extremity weakness during periods of relative hypotension, and one renal artery occluded within a month of stent-graft implantation.

The only other notable events during a mean follow-up of 180 days were one death from chronic pulmonary disease and one case of superior mesenteric artery stenosis (50%) that occurred at 6 months after stent-graft implantation, he added.

All other branches (over 98%) were found to be widely patent at follow-up, and all of the aneurysms remained excluded, and the stent grafts remained intact, Dr. Chuter stated.

"Our results show that multibranched stent-graft implantation eliminates aneurysm flow, while preserving visceral perfusion and avoiding many of the physiologic stresses that are associated with other forms of aneurysm repair. These results support an expanded role for this technique in the treatment of thoracoabdominal aortic aneurysm [TAAA]," Dr. Chuter and his colleagues said.

"Since submitting the abstract we have performed another eight operations of this type, and I have to admit we are still learning from the experience.

"Branched stent-graft implantation for TAAA is still relatively new and quite different from anything else we do. The medium-term advantages over conventional surgery are obvious, but the ultimate role of this technique will depend upon the long-term results. This is one of the limitations of our current study cohort who all have serious comorbid conditions and reduced life expectancy," Dr. Chuter added in the interview.

"Other burning issues," he said, "include the anatomy and physiology of spinal blood flow after endovascular TAAA repair. Paraplegia is rare, but transient symptoms are common and worrying enough to prolong ICU stays, and the causes, and possible treatments, of consumptive coagulopathy and inflammation. We see this phenomenon after any form of endovascular aneurysm repair, but it is more severe and more prolonged after TAAA repair."

When asked to comment on this article, Dr. Ronald Fairman, professor of surgery and chief, division of vascular and endovascular therapy, Hospital of the University of Pennsylvania, Philadelphia, stated: "These remarkable preliminary results demonstrate the feasibility of thoracoabdominal aortic aneurysm (TAA) repair using a totally endovascular approach.

"Clearly this is a highly complex undertaking which requires meticulous preoperative imaging and planning. Unlike infrarenal AAA endografting, TAA stent grafting mandates a learning curve that includes unique skill sets and a three-dimensional appreciation of the visceral aortic segment.

"One wonders if this technology can ultimately be widely disseminated, or will remain limited to a few centers of excellence," concluded Dr. Fairman who is also an editorial advisor for Vascular Specialist.