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CHICAGO -- If any operation should be performed by an experienced team in a high-volume hospital, open thoracoabdominal aortic aneurysm repair is it, Dr. Gilbert R. Upchurch Jr. said at a symposium on vascular surgery sponsored by Northwestern University.

He reported results from 67 elective TAAA repairs performed from 2000 to 2006 at the University of Michigan Hospitals, of which 9% of TAAAs were Crawford classification type I, 46% type II, 17% type III, and 28% type IV. Preoperative risk factors included hypertension (69%), coronary artery disease (24%), chronic obstructive pulmonary disease (21%), history of previous aneurysm repair (36%), vasculitis or connective tissue disorder (13%), and renal insufficiency (7%).The patients' mean age was 62 years, and most (58%) were male.

Mortality associated with repair was only 3% (two patients). The incidence of renal failure requiring either temporary or permanent dialysis was 10%, and that of paraplegia or paraparesis was 12%, Dr. Upchurch said. Cardiac complications were reported in 16% of patients and included atrial fibrillation (13%) and myocardial infarction (1.4%), with stroke and pulmonary embolus/deep venous thrombosis reported in 4% of patients.

Despite significant advances, early mortality with TAAA repair ranges from 4.8% to 15% at single-center institutions of excellence, whereas national data suggest a mortality rate exceeding 20%.

Among 1,542 patients from the National Inpatient Sample who underwent repair of intact TAAAs from 1988 to 1998, overall in-hospital mortality was 22% (J. Vasc. Surg. 2003;37:1169-74). However, mortality varied significantly, depending on whether the patient underwent repair at a low- versus high-volume hospital (27% vs. 15%) or by a low- versus high-volume surgeon (26% vs. 11%).

Nevertheless, these rates compare favorably with a 2-year mortality rate of roughly 75% in patients with untreated large TAAAs.

Most type I TAAAs are primarily managed endovascularly, with one Food and Drug Administration-approved endograft (W.L. Gore \& Associates Inc.'s GORE TAG device), said Dr. Upchurch of the University of Michigan, Ann Arbor. His group previously reported long-term results from a 12-year experience in 73 patients with isolated type I TAAAs that documented a 30-day mortality rate of 5.5% and nearly 60% survival at 4 years (Ann. Thorac. Surg. 2006;82:2147-53).

There are no approved endografts in the United States for Crawford type II-IV TAAAs; these patients are increasingly being treated with hybrid approaches, in which sequential extra-anatomical bypasses are performed to the mesenteric and renal vessels, followed serially by endovascular exclusion of the aneurysm. However, the long-term patency of these extra-anatomical bypasses is unknown, and the devastating complications of renal failure and paralysis remain, he said.

In type II-IV TAAAs, there are two critical portions of the operation, Dr. Upchurch said. The first is the proximal anastomosis, which is transected and performed with a direct end-to-end approach. Second, after the proximal anastomosis is performed, an extensive amount of time is spent in the chest and abdomen permanently clipping all intercostal as well as lumbar arteries that won't be reimplanted. "I think that has really cut back on our blood loss and perhaps may ultimately reduce our paraplegia rate," he said.

Dr. Upchurch's team also performs open TAAA repairs using distal aortic perfusion rather than hypothermic arrest, and standardly uses double-lumen endobronchial tubes, cerebrospinal fluid drainage pneumally, high-thoracic epidural, naloxone administration, low-dose heparin, and Medtronic Inc.'s Carmeda-coated tubing.

"I think that distal aortic perfusion is really critical in all of these patients," Dr. Upchurch said. "I would say the days of clamping and sewing are done." He reported that he had no conflicts of interest to disclose.

When asked to comment, Dr. Ali F. AbuRahma, West Virginia University, Charleston, stated: "As indicated in this study, TAAA remains highly fatal if left untreated, and carries a relatively high morbidity and mortality rate if treated with an open procedure, particularly if done in hospitals and by surgeons that don't experience many of these cases. Endovascular repair of these aneurysms has been advocated over the last several years with relatively lower morbidity and mortality rates. The results of TEVAR have been promising in clinical trials."