title: Effects of thoracic epidural anesthesia on flow and endothelium of internal thoracic artery in coronary artery bypass graft surgery.
abstract: OBJECTIVE
  The internal thoracic artery (ITA) is the preferred conduit for coronary artery bypass graft (CABG) surgery. The authors investigated whether thoracic epidural anesthesia (TEA) as an adjunct to general anesthesia (GA) can increase the blood flow of the ITA.
  
  
  METHODS
  A prospective randomized study.
  
  
  METHODS
  A university hospital.
  
  
  METHODS
  Patients with ischemic heart disease.
  
  
  METHODS
  Thirty patients scheduled for elective CABG surgery were randomized to receive either GA (n = 15) or GA + TEA (n = 15) after receiving institutional review board approval. Demographics showed similarity between the groups. The epidural catheter was inserted in the thoracic region between T1 and T5 levels. In the GA + TEA group, the patients received a 20-mg bolus of 0.25% bupivacaine through epidural catheters 1 hour before surgery, and this was followed by the infusion (20 mg/h) of 0.25% bupivacaine. In all patients, ITA free blood flow was measured before cardiopulmonary bypass and without the administration of any vasodilatory agent. A short segment of ITA was excised for histologic examination; immunocytochemistry analysis was performed using antirabbit polyclonal VEGF antibody, rabbit polyclonal inducible nitric oxide synthase (i-NOS) antibody, and adenosine anti-A2B receptor antibody. The immunoreactivity rates then were evaluated.
  
  
  RESULTS
  The mean ITA free flow in the GA + TEA group was significantly higher than in the GA group (56.0 ± 9.0 mL/min v 39.6 ± 14 mL/min, p = 0.001). Immunostaining intensity in the sections after incubation with each primary antibody increased in the GA + TEA group compared with the GA group.
  
  
  CONCLUSIONS
  The results of this study indicated that TEA increased ITA free blood flow significantly via increased VEGF, i-NOS, and adenosine-A2B receptor expressions. Therefore, the use of TEA as an adjunct to GA might be considered as an alternative to vasoactive agents for increasing ITA flow in CABG surgery.
authors.affiliation: Department of Cardiovascular Surgery, Istanbul Bilim University, Florence Nightingale Hospital, Istanbul, Turkey. selenibis@hotmail.com
authors.forename: Ismihan Selen
authors.initials: IS
authors.lastname: Onan
authors.forename: Burak
authors.initials: B
authors.lastname: Onan
authors.forename: Askın Ali
authors.initials: AA
authors.lastname: Korkmaz
authors.forename: Levent
authors.initials: L
authors.lastname: Oklu
authors.forename: Levent
authors.initials: L
authors.lastname: Kilickan
authors.forename: Suheyla
authors.initials: S
authors.lastname: Gonca
authors.forename: Hakki
authors.initials: H
authors.lastname: Dalcik
authors.forename: Ilhan
authors.initials: I
authors.lastname: Sanisoglu
mesh_terms: D000241:Adenosine / Q000378:metabolism; D000368:Aged; D000767:Anesthesia, Epidural / Q000009:adverse effects*; D000768:Anesthesia, General; D000779:Anesthetics, Local / Q000008:administration & dosage; D002045:Bupivacaine / Q000008:administration & dosage; D001026:Coronary Artery Bypass / Q000379:methods*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D043704:Receptor, Adenosine A2B / Q000096:biosynthesis; D012039:Regional Blood Flow / Q000502:physiology; D018401:Sample Size; D013318:Stroke Volume / Q000502:physiology; D013895:Thoracic Arteries / Q000378:metabolism / Q000502:physiology*; D013904:Thoracic Vertebrae; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
chemical_list: D000779:Anesthetics, Local; D043704:Receptor, Adenosine A2B; D042461:Vascular Endothelial Growth Factor A; D052247:Nitric Oxide Synthase Type II; D000241:Adenosine; D002045:Bupivacaine