title: Differential plasma endothelin levels in subgroups of patients with angina and angiographically normal coronary arteries. Coronary Artery Disease Research Group.
abstract: BACKGROUND
  Raised plasma endothelin concentrations have previously been reported in patients with cardiac syndrome X, but it is not known whether these levels vary between clinically distinct subgroups in this heterogeneous condition.
  
  
  RESULTS
  We compared plasma immunoreactive endothelin levels in 54 patients with angina pectoris and normal coronary angiograms and 21 healthy control subjects. The patient group was divided into 4 clinically distinct subgroups: 7 with left bundle branch block (group A); 7 with previous myocardial infarction (group B); 24 with positive exercise electrocardiography (group C); and 16 with negative exercise electrocardiography (group D). The plasma endothelin concentration was significantly higher in patients compared with control subjects (3.7 [2.9 to 4.3] vs 2.96 [2.4 to 3.4] pg/mL, respectively, median [interquartile range]; P=0.002). Endothelin concentrations were most significantly elevated in group A and group B (4.5 [3.6 to 5.2] pg/mL; P=0.005 and 4.1 [3.9 to 4.5] pg/mL; P=0.001, respectively). Plasma endothelin concentrations were also significantly elevated in group C (3.7 [2.8 to 4.1] pg/mL; P=0.02) but not in group D (3.0 [2.5 to 3.8] pg/mL; P=0.3).
  
  
  CONCLUSIONS
  Plasma endothelin concentration is elevated in patients with angina pectoris and angiographically normal coronary arteries, particularly those with left bundle branch block or previous myocardial infarction.
authors.affiliation: Department of Cardiological Sciences, St. George's Hospital Medical School, London, United Kingdom.
authors.forename: J C
authors.initials: JC
authors.lastname: Kaski
authors.forename: I D
authors.initials: ID
authors.lastname: Cox
authors.forename: J R
authors.initials: JR
authors.lastname: Crook
authors.forename: O A
authors.initials: OA
authors.lastname: Salomone
authors.forename: S
authors.initials: S
authors.lastname: Fredericks
authors.forename: C
authors.initials: C
authors.lastname: Hann
authors.forename: D
authors.initials: D
authors.lastname: Holt
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D016232:Endothelins / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D017566:Microvascular Angina / Q000097:blood* / Q000000981:diagnostic imaging; D008875:Middle Aged
chemical_list: D016232:Endothelins