Ischemia-induced lower extremity neurologic impairment after fenestrated endovascular aneurysm repair.

OBJECTIVE: Placement of large sheaths in the iliac system during fenestrated endovascular aneurysm repair (FEVAR) leads to lower extremity (LE) ischemia that can be associated with serious neurologic complications. We sought to determine the effect of LE ischemic time on neurologic impairment after FEVAR.

METHODS: Consecutive patients who underwent FEVAR at a single institution were analyzed. LE ischemic time was calculated from the time of large sheath (≥18F) insertion to the time of sheath removal from the iliac arteries that led to continuous LE ischemia. The primary outcome was neurologic impairment defined as any new sensory or motor deficit in either LE. Outcomes were analyzed using descriptive statistics and modeled with logistic regression with interaction terms. Each individual LE was used as a unit of analysis.

RESULTS: We examined 101 patients (202 lower extremities) who underwent FEVAR over a 5-year period. The median LE ischemic time was 2.75 hours (range, 0.8-5.2 hours). Neurologic impairment developed in 18 extremities (9%). Of those, 12 (67%) developed mild sensory loss, 6 (33%) complete sensory loss, 4 (22%) loss of proprioception, and 2 (11%) motor dysfunction. Sensory deficit was permanent in four limbs (2%) and motor dysfunction in one limb (0.5%). In all other cases, the neurologic examination returned to baseline by postoperative day 15. Duration of LE ischemic time (odds ratio, 6.3; 95% confidence interval, 3.1-12.4; P < .001) and common iliac artery (CIA) stenosis to a lumen of 8 mm or less (odds ratio, 2.7; 95% confidence interval, 1.5-7.3; P = .002) were independent predictors for the development of neurologic impairment. An interaction term between LE ischemic time and CIA stenosis was statistically significant (P = .042), indicating that the presence of CIA stenosis modifies the effect of LE ischemic time. In those with CIA stenosis to a lumen of 8 mm or less, the risk of neurologic impairment increased rapidly after 2.5 hours of LE ischemia, and became nearly certain after 4 hours of ischemic time. By contrast, patients without CIA stenosis tolerated longer ischemic times and demonstrated a less steep increase in the risk for LE neurologic impairment.

CONCLUSIONS: LE neurologic impairment after FEVAR is strongly associated with LE ischemic time and CIA occlusive disease to a lumen of 8 mm or less. Our data indicate that, when the LE ischemic time is expected to exceed 2.5 hours (in patients with CIA stenosis) or 3 hours (in patients without CIA stenosis), measures to ensure LE perfusion should be given consideration.