title: Changes in cerebrospinal fluid and blood lactate concentrations after stent-graft implantation at critical aortic segment: a preliminary study.
abstract: OBJECTIVE
  Obstruction of blood flow through the arteria radicularis magna (ARM) has been linked with ischemic spinal cord injury after conventional thoracic aortic repair. Whether or not endoluminal stent-grafts, deliberately positioned against this artery can cause similar damage to the spinal cord has not been comprehensively investigated. The purpose of this study was to assess the blood and cerebrospinal fluid (CSF) concentrations of lactate - a well-known biochemical marker of ischemic neurological injury, before and after stent-graft implantation against the ARM.
  
  
  METHODS
  Endoluminal stent-grafting was performed in ten mongrel dogs. In five animals (experimental group), stent-grafts covered the fourth and fifth lumbar segmental arteries - which have been described as the canine equivalents to the ARM in humans. In the remaining five animals (control group), devices of similar length were placed in the lower thoracic aorta. CSF was obtained by cisternal puncture technique at the following time points; before stent-grafting, and 15, 30 and 60 min after stent-grafting. Parallel arterial blood samples were also obtained using a heparinized syringe. All samples were centrifuged and the supernatant analysed for lactate.
  
  
  RESULTS
  The mean preprocedural lactate concentration in the CSF was 1.7+/-0.3 mmol/l. Mean postprocedural levels in the experimental group at 15, 30 and 60 min were 3.1+/-1.9, 3.9+/-1.1 and 11.9+/-2.5 mmol/l, respectively (control values; 2.1+/-1.9, 2.7+/-1.1 and 1.9+/-1.5 mmol/l, respectively). Mean preprocedural blood lactate level was 1.8+/-0.6 mmol/l, while the mean postprocedural concentrations in the experimental group at 15, 30 and 60 min were 2.9+/-1.2, 3.4+/-1.7 and 3.9+/-2.0 mmol/l, respectively. Two out of the five animals in the experimental group suffered mild to moderate hind limb weakness.
  
  
  CONCLUSIONS
  Selective placement of stent-grafts against the ARM in dogs resulted in a conspicuous increase in CSF and blood lactate concentrations 60 min after the procedure with or without physical signs of neurological deficits. Although the small sample size of this preliminary study does not allow any definitive conclusion, it may be worthwhile to confirm the findings in appropriately controlled larger studies.
authors.affiliation: First Department of Surgery, Hamamatsu University School of Medicine, 1-20-1, Handayama, Hamamatsu City, 431-3192, Japan. ahmbashar@yahoo.com
authors.forename: Abul Hasan Muhammad
authors.initials: AH
authors.lastname: Bashar
authors.forename: Kazuya
authors.initials: K
authors.lastname: Suzuki
authors.forename: Teruhisa
authors.initials: T
authors.lastname: Kazui
authors.forename: Mitsuo Yamaguchi
authors.initials: MY
authors.lastname: Okada
authors.forename: Takayasu
authors.initials: T
authors.lastname: Suzuki
authors.forename: Naoki
authors.initials: N
authors.lastname: Washiyama
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Terada
authors.forename: Katsushi
authors.initials: K
authors.lastname: Yamashita
mesh_terms: D000818:Animals; D001027:Aortography; D015415:Biomarkers / Q000378:metabolism; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects* / Q000295:instrumentation; D004285:Dogs; D005260:Female; D019344:Lactic Acid / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism*; D008297:Male; D023421:Models, Animal; D009043:Motor Activity; D010865:Pilot Projects; D011474:Prosthesis Design; D020760:Spinal Cord Ischemia / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D015607:Stents; D013895:Thoracic Arteries / Q000000981:diagnostic imaging / Q000601:surgery*; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D019344:Lactic Acid