title: Therapeutic implications of contractile reserve elicited by dobutamine echocardiography in symptomatic, low-gradient aortic stenosis.
abstract: BACKGROUND
  In patients with heart failure, poor ejection fraction and estimated severe aortic stenosis because of a reduced aortic valve area (AVA) and low gradients, dobutamine echocardiography (DE) was proposed to distinguish afterload mismatch from primary left ventricular dysfunction. In this setting the feasibility and safety of DE and the outcome following management based on DE results were investigated.
  
  
  METHODS
  Forty-eight patients (mean age 73 +/- 9 years; 79% males; AVA 0.7 +/- 0.2 cm2; mean aortic gradient 22 +/- 6 mmHg; ejection fraction 0.28 +/- 0.07; NYHA functional class 2.9 +/- 0.8) underwent DE and were followed up for 24 +/- 21 months. Aortic valve replacement (AVR) was offered to patients with left ventricular contractile reserve (ejection fraction increase > or = 30% at peak DE) and fixed aortic stenosis (AVA increase < or = 0.25 cm2).
  
  
  RESULTS
  DE elicited a left ventricular contractile reserve in 38 patients (79%). Among these, fixed aortic stenosis was present in 28 patients, among whom 19 underwent AVR and 9 declined surgery. The 20 patients without contractile reserve or with relative stenosis (AVA increase > 0.25 cm2) were not considered eligible for surgery. During follow-up, 23 cardiovascular deaths occurred: 2/19 among operated patients, 7/9 among patients who declined surgery and 14/20 among non-eligible patients. Patients with AVR showed a significantly more favorable outcome and improved functional status as compared to the other two groups (NYHA class 1.2 +/- 0.4 vs 2.7 +/- 0.6 at baseline; p < 0.001). Conversely, non-surgical management was the strongest independent predictor of an adverse outcome (relative risk 3.6, 95% confidence interval 1.8-7.3; p < 0.0001).
  
  
  CONCLUSIONS
  In patients with heart failure and estimated severe aortic stenosis, DE could identify a subgroup with a left ventricular contractile reserve and fixed aortic stenosis who gained great benefit from AVR. The clinical outcome of patients who were not operated upon was unfavorable.
authors.affiliation: Division of Cardiology 3, Careggi Hospital, Florence, Italy. cardiologia3@ao-careggi.toscana.it
authors.forename: Alfredo
authors.initials: A
authors.lastname: Zuppiroli
authors.forename: Fabio
authors.initials: F
authors.lastname: Mori
authors.forename: Iacopo
authors.initials: I
authors.lastname: Olivotto
authors.forename: Gabriele
authors.initials: G
authors.lastname: Castelli
authors.forename: Silvia
authors.initials: S
authors.lastname: Favilli
authors.forename: Alberto
authors.initials: A
authors.lastname: Dolara
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D004280:Dobutamine; D025401:Echocardiography, Stress; D005240:Feasibility Studies; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D009200:Myocardial Contraction / Q000502:physiology*; D016019:Survival Analysis; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery
chemical_list: D004280:Dobutamine