title: The association between right coronary artery morphology and endothelial function.
abstract: BACKGROUND
  Two distinct right coronary artery (RCA) morphologies have been previously described: sigma- and C-shaped RCAs. While the C-shaped RCA was significantly associated with atherosclerosis, the sigma-shaped was not. The association of RCA morphology and vascular endothelial function has not yet been assessed.
  
  
  METHODS
  To evaluate the association between the RCA's morphology and flow-mediated endothelium-dependent dilation (FMD) in patients without evidence of atherosclerotic lesions, we prospectively assessed FMD in 49 consecutive patients with non-specific chest pain, who were referred to our laboratory 30+/-10 days after corroboration of normal coronary arteries on coronary angiography. Endothelium-dependent brachial artery FMD and endothelium-independent nitroglycerin-mediated vasodilation (NTG) were assessed using high resolution (15 MHz) linear array ultrasound. The patients were divided into 2 groups according to their RCA morphology on coronary angiograms (sigma and C) which were analyzed by 2 independent readers who were blinded to the patients' FMD results.
  
  
  RESULTS
  The C-shaped group exhibited a significantly lower FMD compared to the sigma-shaped group (9.0+/-4.2% vs. 14.3+/-4.7%, p<0.04, respectively), while NTG was the same in both groups. There were no significant group differences in other variables.
  
  
  CONCLUSIONS
  Endothelium-dependent FMD in the brachial artery is significantly greater in sigma- compared to C-shaped RCA in coronary arteries without overt atherosclerotic lesions, suggesting a potential mechanism whereby C-shaped RCA are predisposed to atherosclerosis.
authors.affiliation: Heart Institute, Chaim Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Yaron
authors.initials: Y
authors.lastname: Arbel
authors.forename: Danny
authors.initials: D
authors.lastname: Dvir
authors.forename: Micha S
authors.initials: MS
authors.lastname: Feinberg
authors.forename: Roy
authors.initials: R
authors.lastname: Beigel
authors.forename: Michael
authors.initials: M
authors.lastname: Shechter
mesh_terms: D000368:Aged; D050197:Atherosclerosis / Q000503:physiopathology; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000503:physiopathology*; D003331:Coronary Vessels / Q000033:anatomy & histology* / Q000473:pathology; D004108:Dilatation, Pathologic; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D014463:Ultrasonography