title: Acute volume reduction with aortic valve replacement immediately improves ventricular mechanics in patients with aortic regurgitation.
abstract: OBJECTIVE
  Few data have been available regarding the immediate response in ventricular mechanics to acute volume reduction caused by aortic valve replacement for aortic regurgitation.
  
  
  METHODS
  We studied 9 patients in the operating room immediately before and after the institution of cardiopulmonary bypass. Left ventricular pressure and cross-sectional area (a surrogate of left ventricular volume) were measured with a catheter-tip manometer and a transesophageal echocardiographic system equipped with automated border-detection technology. Left ventricular pressure-area loops were constructed, and the caval occlusion method was used to obtain the slope of the end-systolic pressure-area relationship and the end-systolic area associated with 100 mm Hg. From the steady-state beats, stroke area was obtained by subtracting the minimum area from the maximum area. Effective arterial elastance, a measure of ventricular afterload, was calculated from end-systolic pressure, and stroke area as follows: effective arterial elastance equals end-systolic pressure divided by stroke area.
  
  
  RESULTS
  Reductions in maximum area (21.0 +/- 8.5 to 16.0 +/- 6.8 cm(2) [SD])and minimum area (15.3 +/- 8.4 to 12.0 +/- 6.1 m(2)) shifted the baseline pressure-area loops to the left. The slope of the end-systolic pressure-area relationship (11.6 +/- 4.8 to 16.0 +/- 7.5 mm Hg/cm(2)) and afterload (effective arterial elastance, 17.9 +/- 11.6 to 26.3 +/- 16.4 mm Hg/cm(2)) were increased, and the end-systolic area associated with 100 mm Hg was reduced (18.3 +/- 10.0 to 13.7 +/- 5.8 cm(2)).
  
  
  CONCLUSIONS
  Correction of volume overload reduced preload (minimum area), shifted the end-systolic pressure-area relationship to the left (decreased end-systolic area), and improved ventricular contractility (increased slope of the end-systolic pressure-area relationship). The result indicated that acute volume reduction favorably influenced ventricular mechanical parameters immediately after the operation.
authors.affiliation: Department of Cardiovascular Surgery, Faculty of Medicine, Kyushu University, Fukuoka, Japan. morita@heart.med.kyushu-u.ac.jp
authors.forename: Shigeki
authors.initials: S
authors.lastname: Morita
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Ochiai
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Tanoue
authors.forename: Manabu
authors.initials: M
authors.lastname: Hisahara
authors.forename: Munetaka
authors.initials: M
authors.lastname: Masuda
authors.forename: Hisataka
authors.initials: H
authors.lastname: Yasui
mesh_terms: D000328:Adult; D000368:Aged; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D006328:Cardiac Catheterization; D002302:Cardiac Output; D002315:Cardiopulmonary Bypass; D017548:Echocardiography, Transesophageal; D019918:Heart Valve Prosthesis Implantation / Q000379:methods; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D011669:Pulmonary Wedge Pressure; D013318:Stroke Volume; D013815:Thermodilution; D016896:Treatment Outcome; D014655:Vascular Resistance; D016277:Ventricular Function, Left; D017725:Ventricular Pressure