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CHICAGO -- Caution must be exercised in the use of thoracic endovascular aortic repair (TEVAR) in high-risk patients, Dr. Mark D. Morasch said at a vascular surgery symposium sponsored by Northwestern University.

Dr. Morasch presented updated data on a study published last year with Northwestern colleague and lead author Dr. Kate Brown that supports the continued use of TEVAR in high-risk patients (J. Vasc. Surg. 2008;47:714-22). The original single-center series included 116 primary TEVAR procedures performed in 115 patients, of which 35% required intervention emergently within 24 hours of hospital admission. With a mean follow-up of 15 months, the 30-day death, stroke, and paraplegia/paresis rates were 5.2%, 8.6%, and 2.6%. Mortality rates as high as 26% have been reported in large series of open repairs.

Still, the investigators acknowledged at the time of publication that, compared with open reconstruction, TEVAR requires more secondary interventions and long-term imaging surveillance to monitor for endoleaks. Endoleaks requiring repeat intervention were reported in eight (6.9%) patients, and delayed graft infections were reported in six (5.2%) patients, four of whom died from infection.

With a mean follow-up of 22 months now available on 154 TEVARs in 147 patients, the 30-day death, stroke, and paraplegia/paresis rates remained stable at 5.2%, 7.7%, and 2.5%, reported Dr. Morasch of the division of vascular surgery, Northwestern University, Chicago. The 7.7% stroke rate in this series is on the higher end of the spectrum, even when compared with open surgical repair series. This rate may be due to the large number of patients treated for very proximal disease, which requires manipulation of the aortic arch with wires and catheters prior to device deployment, he said. In addition, 11 (7.4%) patients in the early part of the series had endograft coverage of the left subclavian artery without prior revascularization via transposition or bypass. Of these, two patients suffered isolated posterior circulation strokes, one developed a symptomatic subclavian steal, and one had an ischemic hand contracture.

These results prompted initiation of an aggressive policy regarding minimal wire and catheter manipulation in the arch and routine branch vessel revascularization prior to coverage, Dr. Morasch said. The team now routinely performs subclavian artery transposition in those patients with dominant left vertebral arterial circulation, in those with anticipated extensive thoracic intercostal vessel coverage, or in those for whom the potential exists for retrograde perfusion of the aneurysm sac or false lumen of a type B dissection. Carotid-to-subclavian bypass is used when patients have had prior LIMA (left internal mammary artery) coronary bypass grafts. As a result of the new policy, the stroke rate has improved over time to 2%, he reported.

A total of 24 patients died after the 30-day perioperative period--one-third because of device failure or progression of pathology. Five patients died from delayed graft infection.

Patients who developed graft infection within 6 weeks of device implantation may have had an unrecognized primary aortic infection at the time of initial presentation, Dr. Morasch suggested. Those who presented with delayed graft infection likely had seeding of their graft from remote infections that developed after the index procedure.

The results suggest that treatment of a known thoracic aortic infection with an endograft should be undertaken with caution or perhaps not at all, he said. In addition to periprocedural antibiotics, lifelong antibiotic coverage also should be considered if an active infection is evident at the time of device implantation.

Delayed endoleaks were reported in 11 (7.4%) patients at an average of 11.6 months after their index procedure. There were five proximal type I leaks, five distal type I leaks, and one type II leak. All required reintervention or resulted in death, Dr. Morasch said.

At baseline, 87% of patients had an American Society of Anesthesiologists (ASA) status of 3 or above and many had comorbid conditions including hypertension (80%), chronic obstructive lung disease (48%), tobacco history (48%), diabetes (20%), and previous aortic surgery (34%). Thirteen patients were aged 80 years or older, and 38% of procedures were emergent.

Dr. Morasch concluded by observing that TEVAR allows such high-risk patients the opportunity for treatment not possible with conventional open surgery, but the results beg the question of who will reap the most benefit.

Dr. Morasch reported that he was an investigator in most of the Gore, Medtronic, and Cook thoracic endograft trials, and a paid consultant for Gore.

When asked to comment on this article, Dr. Brian G. Rubin, professor of surgery, Washington University School of Medicine, St. Louis, stated: "This TEVAR update discusses many issues that parallel the same uncertainties that plagued EVAR in its early and mid-term period: who needs adjuvant procedures, technique-related complications, developments of endoleaks because devices/anatomy/physicianswere inadequate to address the lesion, and resolving if/when/how to treat high risk patients. It is almost certain that TEVAR evolution will continue, and open thoracic aneurysm repair will be reserved for a very select and small percentage of lesions."