title: Neurological complications after left subclavian artery coverage during thoracic endovascular aortic repair: a systematic review and meta-analysis.
abstract: BACKGROUND
  Recent studies suggest an increased risk of neurologic complications after coverage of the left subclavian artery (LSA) during thoracic endovascular aortic repair (TEVAR). The preventative role of preoperative revascularization of the LSA using carotid-subclavian bypass or transposition remains controversial. We assessed this increased risk and the role of revascularization by undertaking a systematic review and meta-analysis of the literature.
  
  
  METHODS
  In the absence of any randomized controlled trials, the Pubmed and Embase databases were searched to identify all series reporting TEVAR without LSA coverage compared with LSA coverage with and without revascularization. The incidence of neurologic complications, namely cerebrovascular accident (CVA) and spinal cord ischemia (SCI), were recorded for each group. Pooled odds ratios (POR) were then calculated for postoperative CVA and SCI.
  
  
  RESULTS
  Compared with patients without LSA coverage, the risk of CVA was increased both in patients with LSA coverage alone (4.7% vs 2.7%; POR, 2.28; 95% confidence interval [CI], 1.28-4.09; P = .005) and in those with LSA coverage after revascularization (4.1% vs 2.6%; POR, 3.18; 95% CI, 1.17-8.65; P = .02). The risk of SCI was also increased in patients requiring LSA coverage (2.8% vs 2.3%; POR, 2.39; 95% CI, 1.30-4.39; P = .005) but not for LSA coverage after revascularization (0.8% vs 2.7%; POR, 1.69; 95% CI, 0.56-5.15; P = .35).
  
  
  CONCLUSIONS
  The risk of neurologic complications is increased after coverage of the LSA during TEVAR. Preemptive revascularization offers no protection against CVA, perhaps indicating a heterogeneous etiology. Revascularization may reduce the risk of SCI, although limited data tempers this conclusion. Improved or perhaps compulsory reporting to registries of a minimum data set may help further assess the exact etiology of these complications and identify a higher-risk subset of patients in whom revascularization might prove protective.
authors.affiliation: Cambridge Vascular Unit, Cambridge University Hospitals NHS Trust, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: David G
authors.initials: DG
authors.lastname: Cooper
authors.forename: Stewart R
authors.initials: SR
authors.lastname: Walsh
authors.forename: Umar
authors.initials: U
authors.lastname: Sadat
authors.forename: Ayesha
authors.initials: A
authors.lastname: Noorani
authors.forename: Paul D
authors.initials: PD
authors.lastname: Hayes
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Boyle
mesh_terms: D001013:Aorta, Thoracic / Q000601:surgery*; D001018:Aortic Diseases / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D006801:Humans; D016017:Odds Ratio; D011474:Prosthesis Design; D018570:Risk Assessment; D012307:Risk Factors; D020760:Spinal Cord Ischemia / Q000209:etiology* / Q000517:prevention & control; D020521:Stroke / Q000209:etiology* / Q000517:prevention & control; D013348:Subclavian Artery / Q000601:surgery*; D016896:Treatment Outcome