title: Low-output, low-gradient aortic stenosis in patients with depressed left ventricular systolic function: the clinical utility of the dobutamine challenge in the catheterization laboratory.
abstract: BACKGROUND
  Although aortic valve replacement can be performed at an acceptable risk level in selected patients with left ventricular systolic dysfunction and low-output, low-gradient aortic stenosis, not all patients presenting with these hemodynamics will benefit from the operation. Some patients may have only mild aortic stenosis, despite a small calculated valve area. We report on the clinical utility of diagnostic dobutamine stimulation during cardiac catheterization in these diagnostically challenging patients.
  
  
  RESULTS
  Thirty-two patients with low-output, low-gradient aortic stenosis and an ejection fraction <40% had dobutamine infusion in the catheterization laboratory. On the basis of the results of the dobutamine test, 21 patients underwent aortic valve replacement. All patients with a final aortic valve area < or =1.2 cm2 at peak dobutamine infusion and a mean gradient of >30 mm Hg were found to have severe calcific aortic stenosis at operation. In the 15 patients in whom contractile reserve was identified during dobutamine challenge (increase in stroke volume >20%), 1 patient died perioperatively (7% mortality) and 12 patients were alive in New York Heart Association class I or II status at follow-up.
  
  
  CONCLUSIONS
  In patients with left ventricular systolic dysfunction and aortic stenosis with a low output and a low mean gradient, dobutamine challenge may aid in selecting those who would benefit from an aortic valve operation.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minn 55905, USA.
authors.forename: Rick A
authors.initials: RA
authors.lastname: Nishimura
authors.forename: J Aaron
authors.initials: JA
authors.lastname: Grantham
authors.forename: Heidi M
authors.initials: HM
authors.lastname: Connolly
authors.forename: Hartzell V
authors.initials: HV
authors.lastname: Schaff
authors.forename: Stuart T
authors.initials: ST
authors.lastname: Higano
authors.forename: David R
authors.initials: DR
authors.lastname: Holmes
mesh_terms: D000318:Adrenergic beta-Agonists; D000368:Aged; D001024:Aortic Valve Stenosis / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D006328:Cardiac Catheterization; D002316:Cardiotonic Agents; D004280:Dobutamine; D004305:Dose-Response Relationship, Drug; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D018579:Patient Selection; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013318:Stroke Volume / Q000187:drug effects; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000175:diagnosis*
chemical_list: D000318:Adrenergic beta-Agonists; D002316:Cardiotonic Agents; D004280:Dobutamine