title: Prevalence of ischaemia in patients with a chronic total occlusion and preserved left ventricular ejection fraction.
abstract: OBJECTIVE
  Previous studies on invasive assessment of collateral function in patients with a chronic total occlusion (CTO) have displayed only a limited increase in collateral flow and high occurrence of coronary steal during pharmacological stress. This could question the necessity for ischaemia testing prior to revascularization of CTOs in the presence of myocardial viability. The purpose of the present study was to determine the prevalence of perfusion impairments in patients with a CTO as assessed by [15O]H2O positron emission tomography (PET).
  
  
  RESULTS
  Seventy-six consecutive patients (60 men, 62 ± 10 years) with a documented CTO and preserved left ventricular ejection fraction (LVEF) were included. All patients underwent PET to assess (hyperaemic) myocardial blood flow (MBF) and coronary flow reserve (CFR). Collateral connection score was 0 in 7 (9%), 1 in 13 (17%), and 2 in 56 (74%) of the cases, with predominantly a high Rentrop grade (96% ≥2). MBF of the target area during hyperaemia was significantly lower when compared with the remote area (1.37 ± 0.37 vs. 2.63 ± 0.71 mL min-1 g-1, P < 0.001). Target to remote ratio during hyperaemia was on average 0.54 ± 0.13, and 73 (96%) patients demonstrated a significantly impaired target to remote ratio (≤0.75). Only 7 (9%) patients displayed a preserved CFR of ≥2.50, whereas coronary steal (CFR <1.0) was observed in 10 (13%) patients.
  
  
  CONCLUSIONS
  Even in the presence of angiographically well-developed collateral arteries, the vast majority of CTO patients with a preserved LVEF showed significantly impaired perfusion. These results suggest that collateral function during increased blood flow demand in viable myocardium is predominantly insufficient.
authors: Department of Cardiology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors: Wijnand J
authors: WJ
authors: Stuijfzand
authors: Department of Cardiology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors: Roel S
authors: RS
authors: Driessen
authors: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors: Pieter G
authors: PG
authors: Raijmakers
authors: Department of Cardiology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors: Mischa T
authors: MT
authors: Rijnierse
authors: Faculty of Medicine and Life Sciences, Universiteit Hasselt, Hasselt, Belgium.|Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium.
authors: Joren
authors: J
authors: Maeremans
authors: Department of Cardiology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors: Maurits R
authors: MR
authors: Hollander
authors: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors: Adriaan A
authors: AA
authors: Lammertsma
authors: Department of Cardiology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors: Albert C
authors: AC
authors: van Rossum
authors: Faculty of Medicine and Life Sciences, Universiteit Hasselt, Hasselt, Belgium.|Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium.
authors: Jo
authors: J
authors: Dens
authors: Department of Cardiology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors: Alexander
authors: A
authors: Nap
authors: Department of Cardiology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors: Niels
authors: N
authors: van Royen
authors: Department of Cardiology, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
authors: Paul
authors: P
authors: Knaapen
mesh_terms: D000368:Aged; D002908:Chronic Disease; D015331:Cohort Studies; D003097:Collateral Circulation; D000072226:Computed Tomography Angiography / Q000379:methods; D017023:Coronary Angiography / Q000379:methods; D003326:Coronary Circulation / Q000502:physiology; D054059:Coronary Occlusion / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000628:therapy; D009204:Myocardial Revascularization / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D013318:Stroke Volume; D016019:Survival Analysis
keywords: chronic total occlusion; collaterals; ischaemia