title: Shop order fracture rate as a risk factor for strut fracture in Björk-Shiley CC60 degrees heart valves.
abstract: OBJECTIVE
  Previous studies have implicated a number of characteristics that predict strut fracture in Björk-Shiley convexo-concave heart valves, including valve size and position, opening angle, and weld date. This study examines whether the specific batch (shop order) with which a valve is associated during manufacture is related to the risk of fracture.
  
  
  METHODS
  Our case-control study of CC60 degrees valves obtained detailed information on the manufacturing characteristics of 147 case and 1094 control valves used. Shop order fracture rate for each valve (percentage of other valves in the same shop order with a fracture) was obtained from the research database maintained by the valve manufacturer.
  
  
  RESULTS
  Shop order was associated with fracture risk. Valves originating from shop orders with the highest two categories of fracture rate were at approximately twice the risk of fracture as other valves, after accounting for the effect of known risk factors.
  
  
  CONCLUSIONS
  Shop order information may provide additional data for assessing the likelihood of valve fracture in individuals being considered for prophylactic explant of heart valves.
authors.affiliation: Epidemiology Resources, Inc., Newton Lower Falls, MA, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Walker
authors.forename: D P
authors.initials: DP
authors.lastname: Funch
authors.forename: L
authors.initials: L
authors.lastname: Bianchi
authors.forename: W J
authors.initials: WJ
authors.lastname: Blot
mesh_terms: D000704:Analysis of Variance; D001705:Bioprosthesis / Q000592:standards*; D016022:Case-Control Studies; D004869:Equipment Safety; D006350:Heart Valve Prosthesis / Q000592:standards*; D006801:Humans; D016015:Logistic Models; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011475:Prosthesis Failure; D012307:Risk Factors; D014186:Transportation / Q000706:statistics & numerical data