title: Assessment of aortic line of elasticity using polynomial regression analysis.
abstract: BACKGROUND
  The aim of this study was to assess the sigmoid line of elasticity in the human aorta.
  
  
  RESULTS
  The pressure-diameter relation was measured in the descending aorta in 120 subjects. In an additional group of 6 subjects, transient vena caval occlusion produced 5 sets of pressure-diameter data. We found that the best fit curve of the pooled pressure-diameter data was a third-order polynomial. A polynomial equation was used to calculate the sigmoid line of elasticity in the entire population and after the administration of diltiazem (15 patients) or enalaprilat (10 patients). The sigmoid line of elasticity was significantly different with respect to age (P<0.001), history of hypertension (P<0.004), and hypercholesterolemia (P<0.02). The difference between the transition point and the peak systolic pressure was increased in normal subjects compared with patients (P<0.0001). The sigmoid line shifted leftward and upward with diltiazem, but it remained unchanged with enalaprilat. During an average of 3 years of follow-up, 19 of 88 patients developed stroke (n=4), unstable angina (n=8), acute myocardial infarction (n=4), or acute pulmonary edema (n=3).
  
  
  CONCLUSIONS
  This approach provides a quantitative evaluation of the aortic line of elasticity, which can differentiate the intrinsic from the extrinsic aortic elastic properties. Furthermore, it is a powerful and independent risk factor for cardiovascular events.
authors.affiliation: Hippokration Hospital, Department of Cardiology, University of Athens, Greece. cstefan@cc.uoa.gr
authors.forename: C
authors.initials: C
authors.lastname: Stefanadis
authors.forename: J
authors.initials: J
authors.lastname: Dernellis
authors.forename: E
authors.initials: E
authors.lastname: Tsiamis
authors.forename: L
authors.initials: L
authors.lastname: Diamantopoulos
authors.forename: A
authors.initials: A
authors.lastname: Michaelides
authors.forename: P
authors.initials: P
authors.lastname: Toutouzas
mesh_terms: D001011:Aorta / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D003327:Coronary Disease / Q000503:physiopathology; D003627:Data Interpretation, Statistical; D004110:Diltiazem / Q000494:pharmacology; D004548:Elasticity; D015773:Enalaprilat / Q000494:pharmacology; D006333:Heart Failure / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D012044:Regression Analysis; D012307:Risk Factors; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D004110:Diltiazem; D015773:Enalaprilat