title: Untreated aortic valve stenosis identified at the time of coronary artery bypass grafting: thresholds associated with adverse prognosis.
abstract: OBJECTIVE
  Aortic valve replacement (AVR) for severe aortic valve stenosis (AS) is a Class I indication at the time of coronary artery bypass grafting (CABG). Management of less-than-severe AS in patients undergoing CABG is uncertain however, because the thresholds at which untreated AS impacts long-term outcome are unclear.
  
  
  METHODS
  We identified 312 patients who underwent isolated CABG between 1993 and 2006 with mild or moderate AS [aortic valve area (AVA) 1-2 cm(2)], and matched them to patients undergoing CABG alone during the same period with similar characteristics but without AS (AVA >2 cm(2)). Long-term survival after CABG and its determinants were analysed using Cox proportional hazards models with AVR as a time-dependent covariate.
  
  
  RESULTS
  Late survival was lower in patients with untreated moderate AS (12 years 23 ± 5.1%) versus mild (42 ± 3.8%) or no AS (38 ± 3.3%) (P = 0.01). Adjusting for age, ejection fraction, heart failure, creatinine, diabetes, peripheral vascular disease (PVD) and interval AVR, moderate AS independently predicted higher mortality [hazard rate (HR) 2.01, 95% confidence interval (CI) 1.49-2.73; P < 0.001]; whereas incremental risk was insignificant for patients with mild AS (HR 1.09, 95% CI 0.85-1.66; P = 0.33). Further stratification showed that highest late postoperative mortality occurred with an AVA of 1-1.25 cm(2) (adjusted HR 2.45, 95% CI 1.57-3.82; P < 0.001), while risk was intermediate with an AVA of 1.25-1.5 cm(2) (HR 1.83, 95% CI 1.28-2.61; P = 0.001).
  
  
  CONCLUSIONS
  Untreated moderate AS is an independent determinant of excess late mortality following isolated CABG, and mortality risk increases with decreasing AVA. Those with moderate-to-severe AS (AVA 1-1.25 cm(2)) have more than 2-fold greater long-term mortality compared with those without AS. These data define AS severity thresholds for clinical trials aimed at defining whether valve intervention might mitigate this risk.
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Nassir M
authors.initials: NM
authors.lastname: Thalji
authors.affiliation: Mayo Clinic, Rochester, MN, USA suri.rakesh@mayo.edu.
authors.forename: Rakesh M
authors.initials: RM
authors.lastname: Suri
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Maurice
authors.initials: M
authors.lastname: Enriquez-Sarano
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Bernard J
authors.initials: BJ
authors.lastname: Gersh
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Marianne
authors.initials: M
authors.lastname: Huebner
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Dearani
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Harold M
authors.initials: HM
authors.lastname: Burkhart
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Li
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Greason
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Hector I
authors.initials: HI
authors.lastname: Michelena
authors.affiliation: Mayo Clinic, Rochester, MN, USA.
authors.forename: Hartzell V
authors.initials: HV
authors.lastname: Schaff
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000175:diagnosis* / Q000401:mortality* / Q000601:surgery*; D001026:Coronary Artery Bypass / Q000401:mortality*; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011379:Prognosis
keywords: Aortic stenosis; Bypass surgery; Prognosis