title: External validation of established risk adjustment models for procedural complications after percutaneous coronary intervention.
abstract: BACKGROUND
  Workable risk models for patients undergoing percutaneous coronary intervention (PCI) are needed urgently.
  
  
  OBJECTIVE
  To validate two proposed risk adjustment models (Mayo Clinic Risk Score (MC), USA and North West Quality Improvement Programme (NWQIP), UK models) for in-hospital PCI complications on an independent dataset of relatively high risk patients undergoing PCI.
  
  
  METHODS
  Tertiary centre in northern England.
  
  
  METHODS
  Between September 2002 and August 2006, 5034 consecutive PCI procedures (validation set) were performed on a patient group characterised by a high incidence of acute myocardial infarction (MI; 16.1%) and cardiogenic shock (1.7%). Two external models-the NWQIP model and the MC model-were externally validated.
  
  
  METHODS
  Major adverse cardiovascular and cerebrovascular events: in-hospital mortality, Q-wave MI, emergency coronary artery bypass grafting and cerebrovascular accidents.
  
  
  RESULTS
  An overall in-hospital complication rate of 2% was observed. Multivariate regression analysis identified risk factors for in-hospital complications that were similar to the risk factors identified by the two external models. When fitted to the dataset, both external models had an area under the receiver operating characteristic curve >or=0.85 (c index (95% CI), NWQIP 0.86 (0.82 to 0.9); MC 0.87(0.84 to 0.9)), indicating overall excellent model discrimination and calibration (Hosmer-Lemeshow test, p>0.05). The NWQIP model was accurate in predicting in-hospital complications in different patient subgroups.
  
  
  CONCLUSIONS
  Both models were externally validated. Both predictive models yield comparable results that provide excellent model discrimination and calibration when applied to patient groups in a different geographic population other than that in which the original model was developed.
authors.affiliation: Department of Cardiology, The James Cook University Hospital, Middlesbrough, UK.
authors.forename: B
authors.initials: B
authors.lastname: Kunadian
authors.forename: J
authors.initials: J
authors.lastname: Dunning
authors.forename: R
authors.initials: R
authors.lastname: Das
authors.forename: A P
authors.initials: AP
authors.lastname: Roberts
authors.forename: R
authors.initials: R
authors.lastname: Morley
authors.forename: A J
authors.initials: AJ
authors.lastname: Turley
authors.forename: D
authors.initials: D
authors.lastname: Twomey
authors.forename: J A
authors.initials: JA
authors.lastname: Hall
authors.forename: R A
authors.initials: RA
authors.lastname: Wright
authors.forename: A G C
authors.initials: AG
authors.lastname: Sutton
authors.forename: D F
authors.initials: DF
authors.lastname: Muir
authors.forename: M A
authors.initials: MA
authors.lastname: de Belder
mesh_terms: D054058:Acute Coronary Syndrome / Q000628:therapy; D000368:Aged; D000369:Aged, 80 and over; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects*; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D004630:Emergencies; D004739:England; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology; D020379:Risk Adjustment / Q000379:methods*; D012770:Shock, Cardiogenic / Q000209:etiology; D016896:Treatment Outcome