title: Echocardiographic assessment of aortic elastic properties with automated border detection in an ICU: in vivo application of the arctangent Langewouters model.
abstract: We studied whether combined pressure and transesophageal ultrasound monitoring is feasible in the intensive care unit (ICU) setting for global cardiovascular hemodynamic monitoring [systemic vascular resistance (SVR) and total arterial compliance (C(PPM))] and direct estimation of local ascending and descending aortic mechanical properties, i.e., distensibility and compliance coefficients (DC and CC). Pressure-area data were fitted to the arctangent Langewouters model, with aortic cross-sectional area obtained via automated border detection. Data were measured in 19 subjects at baseline, during infusion of sodium nitroprusside (SNP), and after washout. SNP infusion lowered SVR from 1.15 +/- 0.40 to 0.80 +/- 0.32 mmHg.ml(-1).s (P < 0.05), whereas C(PPM) increased from 0.87 +/- 0.46 to 1.02 +/- 0.42 ml/mmHg (P < 0.05). DC and CC increased from 0.0018 +/- 0.0007 to 0.0025 +/- 0.0009 l/mmHg (P < 0.05) and from 0.0066 +/- 0.0028 to 0.0083 +/- 0.0026 cm2/mmHg (P < 0.05), respectively, at the descending, but not ascending, aorta. The Langewouters model fitted the descending aorta data reasonably well. Assessment of local mechanical properties of the human ascending aorta in a clinical setting by automated border detection remains technically challenging.
authors.affiliation: Intensive Care Department, Ghent University Hospital, Ghent University, Ghent, Belgium.
authors.forename: Jan R
authors.initials: JR
authors.lastname: Heerman
authors.forename: Patrick
authors.initials: P
authors.lastname: Segers
authors.forename: Carl D
authors.initials: CD
authors.lastname: Roosens
authors.forename: Frank
authors.initials: F
authors.lastname: Gasthuys
authors.forename: Pascal R
authors.initials: PR
authors.lastname: Verdonck
authors.forename: Jan I
authors.initials: JI
authors.lastname: Poelaert
mesh_terms: D000368:Aged; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000502:physiology*; D001794:Blood Pressure; D002302:Cardiac Output; D001026:Coronary Artery Bypass; D004452:Echocardiography / Q000295:instrumentation / Q000379:methods*; D004548:Elasticity; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D009599:Nitroprusside; D011182:Postoperative Care; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D009599:Nitroprusside