title: Current perspectives on coronary chronic total occlusions: the Canadian Multicenter Chronic Total Occlusions Registry.
abstract: OBJECTIVE
  The purpose of this study was to determine the prevalence, clinical characteristics, and management of coronary chronic total occlusions (CTOs) in current practice.
  
  
  BACKGROUND
  There is little evidence in contemporary literature concerning the prevalence, clinical characteristics, and treatment decisions regarding patients who have coronary CTOs identified during coronary angiography.
  
  
  METHODS
  Consecutive patients undergoing nonurgent coronary angiography with CTO were prospectively identified at 3 Canadian sites from April 2008 to July 2009. Patients with previous coronary artery bypass graft surgery or presenting with acute ST-segment elevation myocardial infarction were excluded. Detailed baseline clinical, angiographic, electrocardiographic, and revascularization data were collected.
  
  
  RESULTS
  Chronic total occlusions were identified in 1,697 (18.4%) patients with significant coronary artery disease (>50% stenosis in ≥1 coronary artery) who were undergoing nonemergent angiography. Previous history of myocardial infarction was documented in 40% of study patients, with electrocardiographic evidence of Q waves corresponding to the CTO artery territory in only 26% of cases. Left ventricular function was normal in >50% of patients with CTO. Half the CTOs were located in the right coronary artery. Almost half the patients with CTO were treated medically, and 25% underwent coronary artery bypass graft surgery (CTO bypassed in 88%). Percutaneous coronary intervention was done in 30% of patients, although CTO lesions were attempted in only 10% (with 70% success rate).
  
  
  CONCLUSIONS
  Chronic total occlusions are common in contemporary catheterization laboratory practice. Prospective studies are needed to ascertain the benefits of treatment strategies of these complex patients.
authors.affiliation: Schulich Heart Program, Sunnybrook Health Sciences Centre, University of Toronto, 2075 Bayview Ave., Toronto, Ontario, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Fefer
authors.forename: Merril L
authors.initials: ML
authors.lastname: Knudtson
authors.forename: Asim N
authors.initials: AN
authors.lastname: Cheema
authors.forename: P Diane
authors.initials: PD
authors.lastname: Galbraith
authors.forename: Azriel B
authors.initials: AB
authors.lastname: Osherov
authors.forename: Sergey
authors.initials: S
authors.lastname: Yalonetsky
authors.forename: Sharon
authors.initials: S
authors.lastname: Gannot
authors.forename: Michelle
authors.initials: M
authors.lastname: Samuel
authors.forename: Max
authors.initials: M
authors.lastname: Weisbrod
authors.forename: Daniel
authors.initials: D
authors.lastname: Bierstone
authors.forename: John D
authors.initials: JD
authors.lastname: Sparkes
authors.forename: Graham A
authors.initials: GA
authors.lastname: Wright
authors.forename: Bradley H
authors.initials: BH
authors.lastname: Strauss
mesh_terms: D000368:Aged; D002170:Canada / Q000453:epidemiology; D017023:Coronary Angiography; D054059:Coronary Occlusion / Q000453:epidemiology* / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012042:Registries