title: Quantitative determinants of the outcome of asymptomatic mitral regurgitation.
abstract: BACKGROUND
  The clinical outcome of asymptomatic mitral regurgitation is poorly defined, and the treatment is uncertain. We studied the effect on the outcome of quantifying mitral regurgitation according to recent guidelines.
  
  
  METHODS
  We prospectively enrolled 456 patients (mean [+/-SD] age, 63+/-14 years; 63 percent men; ejection fraction, 70+/-8 percent) with asymptomatic organic mitral regurgitation, quantified according to current recommendations (regurgitant volume, 66+/-40 ml per beat; effective regurgitant orifice, 40+/-27 mm2).
  
  
  RESULTS
  The estimated five-year rates (+/-SE) of death from any cause, death from cardiac causes, and cardiac events (death from cardiac causes, heart failure, or new atrial fibrillation) with medical management were 22+/-3 percent, 14+/-3 percent, and 33+/-3 percent, respectively. Independent determinants of survival were increasing age, the presence of diabetes, and increasing effective regurgitant orifice (adjusted risk ratio per 10-mm2 increment, 1.18; 95 percent confidence interval, 1.06 to 1.30; P<0.01), the predictive power of which superseded all other qualitative and quantitative measures of regurgitation. Patients with an effective regurgitant orifice of at least 40 mm2 had a five-year survival rate that was lower than expected on the basis of U.S. Census data (58+/-9 percent vs. 78 percent, P=0.03). As compared with patients with a regurgitant orifice of less than 20 mm2, those with an orifice of at least 40 mm2 had an increased risk of death from any cause (adjusted risk ratio, 2.90; 95 percent confidence interval, 1.33 to 6.32; P<0.01), death from cardiac causes (adjusted risk ratio, 5.21; 95 percent confidence interval, 1.98 to 14.40; P<0.01), and cardiac events (adjusted risk ratio, 5.66; 95 percent confidence interval, 3.07 to 10.56; P<0.01). Cardiac surgery was ultimately performed in 232 patients and was independently associated with improved survival (adjusted risk ratio, 0.28; 95 percent confidence interval, 0.14 to 0.55; P<0.01).
  
  
  CONCLUSIONS
  Quantitative grading of mitral regurgitation is a powerful predictor of the clinical outcome of asymptomatic mitral regurgitation. Patients with an effective regurgitant orifice of at least 40 mm2 should promptly be considered for cardiac surgery.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minn 55905, USA. sarano.maurice@mayo.edu
authors.forename: Maurice
authors.initials: M
authors.lastname: Enriquez-Sarano
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Avierinos
authors.forename: David
authors.initials: D
authors.lastname: Messika-Zeitoun
authors.forename: Delphine
authors.initials: D
authors.lastname: Detaint
authors.forename: Maryann
authors.initials: M
authors.lastname: Capps
authors.forename: Vuyisile
authors.initials: V
authors.lastname: Nkomo
authors.forename: Christopher
authors.initials: C
authors.lastname: Scott
authors.forename: Hartzell V
authors.initials: HV
authors.lastname: Schaff
authors.forename: A Jamil
authors.initials: AJ
authors.lastname: Tajik
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001281:Atrial Fibrillation / Q000209:etiology; D015150:Echocardiography, Doppler; D005260:Female; D006333:Heart Failure / Q000209:etiology; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging; D008944:Mitral Valve Insufficiency / Q000145:classification* / Q000150:complications* / Q000401:mortality / Q000601:surgery; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012720:Severity of Illness Index; D015996:Survival Rate; D016896:Treatment Outcome; D016276:Ventricular Function