title: Myocardial and Cardiocirculatory Reserve in Asymptomatic Aortic Stenosis and Preserved Ejection Fraction.
abstract: OBJECTIVE
  Managing patients with asymptomatic severe aortic stenosis (AS) remains a major challenge. Myocardial as well as cardiocirculatory reserve have been hypothesized to predict outcome in patients with asymptomatic AS.
  
  
  METHODS
  A total of 48 patients (indexed aortic valve area 0.39 +/- 0.12 cm2/m2; ejection fraction (EF) 67 +/- 7%) underwent spiroergometry and dobutamine stress echocardiography. Death or valve surgery served as a combined endpoint for follow up.
  
  
  RESULTS
  Thirty-seven patients reached the endpoint after a mean of 756 days (range: 100-2146 days). Age- and gender-corrected univariate Cox proportional analysis revealed the presence of mild obstructive lung disease, stroke work loss (SWL), end-systolic diameter index, and E/Flow propagation velocity as the best predictive clinical, valvular, cardiostructural, and left ventricular filling pressure parameters, respectively. After inclusion of these parameters into a baseline multivariable Cox proportional hazard model, SWL (HR 1.21 per rise of 1 unit, CI 1.08-1.35, p = 0.0005) and female gender (HR 3.37, CI 1.50-7.59, p = 0.0044) were independently predictive. Similarly, the best-performing myocardial parameter, EF after dobutamine, was independently predictive (HR 0.75 per 5 units, CI 0.57-0.99, p = 0.035) after inclusion. The best-performing exercise capacity parameter, Watt(max), was of borderline significance (HR 0.93 per 5 units, CI 0.86-1.00, p = 0.0505). For each parameter, cut-off values were determined by time-dependent receiver-operator characteristics. The Kaplan-Meier curves of the patients above versus below the cut-offs differed significantly for SWL (p = 0.001), Wattm (p = 0.001), and gender (p = 0.013).
  
  
  CONCLUSIONS
  Besides SWL and female gender, the EF after dobutamine as well as highest exercise stress intensity reached are helpful in determining the prognosis of asymptomatic patients with moderate-severe AS.
authors.forename: Olaf
authors.initials: O
authors.lastname: Schulz
authors.forename: Debora
authors.initials: D
authors.lastname: Brala
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Allison
authors.forename: Ingolf
authors.initials: I
authors.lastname: Schimke
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D019540:Area Under Curve; D058070:Asymptomatic Diseases; D002316:Cardiotonic Agents / Q000008:administration & dosage; D003326:Coronary Circulation; D004280:Dobutamine / Q000008:administration & dosage; D025401:Echocardiography, Stress; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine