title: The myocardium supplied by a chronic total occlusion is a persistently ischemic zone.
abstract: Well-developed collaterals to a myocardial segment supplied by a chronic total occlusion (CTO) and/or left ventricular dysfunction in the CTO regions in patients with chronic stable angina suggest that severe ischemia is unlikely to be present. We evaluated the presence and severity of ischemia using fractional flow reserve (FFR) of the myocardium supplied by a CTO in patients and compared the results with a non-CTO control group.
  
  
  METHODS
  Patients undergoing FFR and successful percutaneous coronary intervention (PCI) of a CTO were evaluated and compared to a matched non-CTO control group.
  
  
  RESULTS
  One hundred patients were included (50 CTO/50 controls). CTO lesions were longer (31.6 ± 18.9 vs 20.2 ± 14.9 mm, P = 0.004) and required more stents (2.2 ± 0.8 vs 1.2 ± 0.5, P = 0.001). FFR was lower (P = 0.0003) with CTO (0.45 ± 0.15) than controls (0.58 ± 0.17) prior to intervention but similar after PCI (CTO 0.91 ± 0.05 vs non-CTO 0.90 ± 0.08). All CTO patients demonstrated an ischemic FFR, even with severe regional dysfunction or well-developed collaterals. Resting ischemia was present in 78% (39/50) of CTO patients as evidenced by a resting Pd /Pa of <0.80.
  
  
  CONCLUSIONS
  In symptomatic patients, a CTO, even with regional left ventricular impairment and/or excellent collateral development, reveals an ischemic zone. This ischemic zone can be normalized by PCI with outcomes appearing to be comparable to non-CTO patients.
authors.affiliation: WellStar Cardiology, North Fulton Hospital, 3000 Hospital Boulevard, Roswell, Georgia; Department of Internal Medicine, Division of Cardiology, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Sachdeva
authors.forename: Mayank
authors.initials: M
authors.lastname: Agrawal
authors.forename: Shawn E
authors.initials: SE
authors.lastname: Flynn
authors.forename: Gerald S
authors.initials: GS
authors.lastname: Werner
authors.forename: Barry F
authors.initials: BF
authors.lastname: Uretsky
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D002908:Chronic Disease; D003097:Collateral Circulation; D017023:Coronary Angiography; D054059:Coronary Occlusion / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D062645:Percutaneous Coronary Intervention / Q000295:instrumentation; D012720:Severity of Illness Index; D015607:Stents; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D016277:Ventricular Function, Left
keywords: chronic total occlusion; fractional flow reserve; percutaneous coronary intervention; stenting