EUROSTAR Shows Risks For Neuro Complications

BY MARK S. LESNEY

Paraplegia or paraparesis after endovascular treatment of thoracic aortic disease was independently correlated with blockage of the left subclavian artery without revascularization, renal failure, or number of stent grafts used, according to Dr. Jacob Buth.

He and his colleagues reviewed 606 patients recruited from 58 European institutions who were prospectively enrolled in the European Collaborators on Stent Graft Techniques for Thoracic Aortic Aneurysm and Dissection Repair (EUROSTAR) thoracic registry database between July 2000 and July 2006.

Thoracic pathologies were either emergent or elective, and included degenerative aneurysm (291 patients, or 48%); aortic dissection (215, 35%); traumatic rupture (67, 11%); false anastomotic aneurysm (24, 4%); and infectious or not characterized disorders (9, 1.5%). The end points included perioperative spinal cord ischemia or stroke. Dr. Buth presented his results at the Vascular Annual Meeting.

Regression analysis was used to assess the clinical factors that would influence neurologic events.

Overall patient mortality at 1 month in the registry population was 60 (9.9%). Paraplegia or paraparesis developed in 15 patients (2.5%) and stroke occurred in 19 patients (3.1%). The multivariate regression analysis showed significant independent correlation with paraplegia or paraparesis for three factors: left subclavian artery covering without revascularization (P = .023, with an odds ratio of 3.9); renal failure (P = .017, OR 3.7); and the number of used stent grafts greater than or equal to three (P = .041, OR 3.4).

The only correlating factor that was found to be associated with perioperative stroke was the duration of the procedure (P = .0045, OR 6.4) irrespective of whether it was an endovascular or open repair.

Previous researchers have suggested that endovascular repair of thoracic aortic lesions appears to decrease the incidence of spinal cord injury when compared with open surgery. Possible reasons given for this in the literature are shorter operative times, lack of aortic cross-clamping, lower incidence of hypotension, and less blood loss.

In this study, the endovascular treatment of aortic disease also demonstrated a lower rate of spinal cord ischemia than did open repair, but the same was not true for intracranial stroke, in which the incidence was found to be the same, according to Dr. Buth and his colleagues from Catharina Hospital, Eindhoven, the Netherlands, and the Royal Liverpool (England) University Hospital.

In particular, however, "the clinical significance of left subclavian artery coverage without revascularization on collateral perfusion [of the spinal cord] has not been confirmed previously," Dr. Buth stated in an interview.

"To properly select patients for subclavian artery revascularization, considerable experience with imaging of this vascular territory is required." When after careful CT, MRI, or angiography there still is doubt about the left vertebral artery blood supply, a subclavian-carotid transposition may be the safest option, he said.

He also reiterated the importance of other procedural factors in outcomes, saying that his group's research also found that extensive covering of the intercostal arteries reflected by the use of multiple stent grafts correlated with spinal cord ischemia, and that "intracranial stroke was associated with lengthy manipulation of wires, catheters, and introducer sheaths within the aortic arch."

When asked to comment on this article, Dr. Robert P. Cambria, professor of surgery at Harvard Medical School, and chief of the division of vascular and endovascular surgery at the Massachusetts General Hospital, Boston, stated: "These provocative data suggest that routine coverage of the left subclavian artery origin in the course orf thoracic aortic stent graft repair is to be avoided because such practice is apparently associated with increased risk of spinal cord ischemia.

"The power of the Eurostar registry lies in the large sample size, which is crucial in consideration of a complication (i.e. cord ischemia) that occurs in some 5% of patients. ... The overall neurologic complications in this series were very low, further emphasizing this point.

"Indeed at the same SVS meeting we reported preliminary results of a multicenter study of TEVAR for complex thoracic aortic pathology, and in a case of traumatic tear reported a devastating paraplegia case wherein left subclavian artery coverage was the only apparent explanation.

"The Eurostar data are consistent with a prior review of this topic, which also suggested increased complications with left subclavian artery coverage.

"The implication for surgeons is that at the very least complete radiographic evaluation of both vertebrals and their contributions to the basilar artery (these are the medullary feeders of proximal cord circulation) is mandatory when left subclavian coverage is anticipated in the course of TEVAR," Dr. Cambria concluded.