Neurologic complications after the frozen elephant trunk procedure: A meta-analysis of more than 3000 patients

Objective: The frozen elephant trunk technique's safety regarding spinal cord ischemia has been questioned. We used a meta-analysis to determine the rates of adverse neurologic events and mortality. Methods: We searched PubMed/Medline, Embase, Scopus, and Cochrane databases (inception to April 2018) to identify studies of neurologic events after the frozen elephant trunk procedure. Separate meta-analyses were conducted with random-effects models to assess frozen elephant trunk associations with spinal cord ischemia, stroke, operative mortality, and all adverse events combined. Subgroup analyses compared outcomes in patients with acute versus nonacute type A dissection and aneurysm and with different extents of coverage. Results: Thirty-five studies (total N = 3154) met inclusion criteria. The pooled rates of the outcomes of interest were 4.7% (95% confidence interval, 3.5-6.2) for spinal cord ischemia, 7.6% (95% confidence interval, 5.0-11.5) for stroke, and 8.8% (95% confidence interval, 7.0-10.9) for operative mortality. The spinal cord ischemia event rate was higher with stent length 15 cm or greater or coverage to T8 or beyond than with stent length of 10 cm (11.6% vs 2.5%, P < .001). Adverse event rates in patients with acute type A aortic dissection versus nonacute dissection or aneurysm were as follows: mortality 9.2% versus 7.6% (P = .46), stroke 9.3% versus 6.6% (P = .51), and overall adverse events 22.0% versus 16.5% (P = .41). Conclusions: As the frozen elephant trunk procedure becomes more popular, accurate data regarding outcomes are vital. We associated the frozen elephant trunk technique with (nonsignificantly) more adverse events overall in acute type A dissection cases. Stent length of 10 cm was associated with significantly less risk of spinal cord ischemia. Using a stent 15 cm or greater or coverage extending to T8 or farther should be avoided.