Thoracic Endograft Safer Than Surgery at 2 Years


SAN FRANCISCO — Use of the Gore TAG thoracic endograft markedly reduced morbidity and mortality, compared with open repair through 2 years of follow-up, R. Scott Mitchell, M.D., said at the annual meeting of the American Association for Thoracic Surgery.

Earlier this year, the catheter-delivered Gore TAG device was approved as the first stent graft for treating descending thoracic aortic aneurysms. It consists of a Teflon tube covered by a nitinol exoskeleton. Although several endovascular devices for treatment of abdominal aortic aneurysms are on the market, endoprostheses for the less frequent thoracic aortic aneurysms has been slower to develop. The Gore TAG was the first such device to enter clinical trials, which were halted for 2 years upon discovery that it was prone to asymptomatic stent fractures along the graft spine.

The 17-center prospective nonrandomized trial compared outcomes in 140 patients with endovascular repair using the Gore TAG and a historical control group of 94 patients with a conventional open repair.

Mean estimated procedural blood loss was 472 mL in the Gore TAG group vs. 2,402 mL with open surgery. Temporary or permanent paraplegia occurred within 30 days in 3% of the Gore TAG group and 14% of controls. Early mortality in the Gore TAG group was 2%, compared with 6% in controls. The 3.5% perioperative stroke rate in the Gore TAG group was significantly lower than in controls. Rates of renal dysfunction and cardiac complications were also lower. ICU time and hospital length of stay were markedly shorter in the Gore TAG patients, who were able to return to normal activities in an average of 30 days, vs. 78 days in the open-surgery patients.

The rate of 2-year freedom from aneurysm-related mortality was 98% in the stent group and 91% in controls. However, all-cause mortality was similar in the two groups, at about 25%, according to Dr. Mitchell, professor of cardiovascular surgery at Stanford (Calif.) University and co-principal investigator in the trial.

Over 2 years of follow-up, 15% of Gore TAG-treated patients had an endoleak, for which four underwent endovascular revision; one required an open conversion.

During follow-up, the aneurysm sac decreased in size by more than 5 mm in 24 patients and grew by more than 5 mm in 11 patients. There have been no late aneurysm ruptures.

“I think these complications will be ongoing. Hopefully they'll be decreasing with time. But we don't know that, so these patients will require lifelong follow-up,” the surgeon stressed.

The device is not for everyone. It requires access vessels that allow passage of a 20–24 French sheath. The patient must have a minimum 2-cm landing zone of normal thoracic aorta free of thrombus or calcification proximal and distal to the aneurysm. Patients with Marfan syndrome and other connective tissue disorders were excluded from the trial, and Dr. Mitchell urged that the same policy be followed in clinical practice because the device is unlikely to be effective in that population.

Roughly 10,000–15,000 thoracic aortic aneurysms are diagnosed annually, often in elderly patients who are not good surgical candidates. The Gore TAG device, which spares patients the large chest incision and prolonged aortic clamping entailed in open surgery, could expand the pool of patients who can undergo repair.

Recognizing this, discussant Joseph S. Coselli, M.D., of Baylor College of Medicine in Houston, predicted, “this technology will forever alter how we approach descending thoracic aortic aneurysm pathology.” He added, however, that many participants in the control group for this trial were retrospectively acquired.

“It's not the best control group. We admit that,” said Dr. Mitchell. “But I think all of us are aware of the difficulties in trying to get a very aware public to enroll in a randomized trial.”

He is a consultant to W.L. Gore & Associates Inc., the study sponsor.

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