title: Intraoperative detection of intimal lipid in the radial artery predicts degree of postoperative spasm.
abstract: BACKGROUND
  The radial artery's (RA) tendency to spasm when used as a bypass graft may relate to features of the RA itself. We imaged RA conduits before and after CABG in order to characterize intimal abnormalities that might relate to the risk of spasm.
  
  
  METHODS
  RA conduits from thirty-two CABG patients were imaged intraoperatively using catheter-based optical coherence tomography (OCT) and again on day 5 using 64-channel MDCT angiography. The change in luminal diameter between timepoints was measured in the proximal, mid and distal RA. "Spasm" was defined as focal or diffuse luminal narrowing to a diameter less than the target coronary. Lipid content in the RA was quantified by the degree of light attenuation on the OCT image.
  
  
  RESULTS
  Postoperative spasm was diagnosed in 18 of 32 (56%) RA grafts with the distal RA showing the most severe change versus the mid and proximal portions (-24.1+/-43.2% vs. -15.3+/-40.7%, -9.0+/-42.5% change in diameter respectively, p<0.01). The degree of attenuation of the OCT signal produced by the RA was strongly correlated with % diameter change (R=0.64, p=0.0005) and was significantly more pronounced in grafts with spasm versus no spasm (-1.97+/-0.61mm(-1) vs. -0.81+/-0.57mm(-1), p<0.0001). Histology confirmed lipid deposits in areas of RA with strong attenuation.
  
  
  CONCLUSIONS
  RA conduits otherwise considered acceptable for bypass grafting were often found by OCT imaging to have a substantial amount of lipid, which in turn strongly relates to the risk of postoperative spasm. Screening conduits based on characteristics of intimal quality may improve results following RA grafting.
authors.affiliation: University of Maryland School of Medicine, Department of Surgery, Baltimore, United States.
authors.forename: Emile N
authors.initials: EN
authors.lastname: Brown
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Burris
authors.forename: Zachary N
authors.initials: ZN
authors.lastname: Kon
authors.forename: Michael C
authors.initials: MC
authors.lastname: Grant
authors.forename: Philip S
authors.initials: PS
authors.lastname: Brazio
authors.forename: Chenyang
authors.initials: C
authors.lastname: Xu
authors.forename: Patrick
authors.initials: P
authors.lastname: Laird
authors.forename: Junyen
authors.initials: J
authors.lastname: Gu
authors.forename: Seeta
authors.initials: S
authors.lastname: Kallam
authors.forename: Pranjal
authors.initials: P
authors.lastname: Desai
authors.forename: Robert S
authors.initials: RS
authors.lastname: Poston
mesh_terms: D000368:Aged; D000792:Angiography / Q000379:methods; D001706:Biopsy; D017023:Coronary Angiography / Q000379:methods; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008055:Lipids / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011184:Postoperative Period; D017534:Radial Artery / Q000473:pathology* / Q000637:transplantation*; D012306:Risk; D013035:Spasm / Q000378:metabolism* / Q000517:prevention & control*; D017539:Tunica Intima / Q000473:pathology*
chemical_list: D008055:Lipids