title: Importance of collateral circulation in coronary heart disease.
abstract: OBJECTIVE
  Collateral arteries are a common but inconsistent finding in coronary heart disease (CHD). We endeavoured to review the methods for coronary artery collateral assessment, the predictors and clinical importance of collateral blood flow, and the potential for therapeutic augmentation of collateral anastomoses.
  
  
  RESULTS
  While many methods have been used to assess collateral blood flow only a few have been formally validated. Collateral flow index, as determined by measurement of intra-coronary pressure or flow velocity, is the most robust measure of collateral flow. These techniques have led to important advances in our understanding of collateral artery function. Coronary collateral arteries may prevent myocardial ischaemia in healthy subjects and in patients with CHD. A functional collateral circulation may lead to reduced ischaemia, preservation of ventricular function, and an improved prognosis. Recent trials have demonstrated that vascular progenitor cell therapies may improve ventricular function following acute myocardial infarction, raising the possibility of effective biological treatments to improve myocardial blood flow and prognosis in CHD.
  
  
  CONCLUSIONS
  Coronary collateral anastomoses represent a prognostically important adaptive response in patients with CHD. Therapeutic augmentation of collaterals with emerging biological therapies represents a desirable goal for treating CHD patients.
authors.affiliation: Department of Medicine, Institut de Cardiologie de Montréal, Montréal, Québec, Canada. colin.berry@clinmed.gla.ac.uk
authors.forename: Colin
authors.initials: C
authors.lastname: Berry
authors.forename: Kanarath P
authors.initials: KP
authors.lastname: Balachandran
authors.forename: Philippe L
authors.initials: PL
authors.lastname: L'Allier
authors.forename: Jacques
authors.initials: J
authors.lastname: Lespérance
authors.forename: Raoul
authors.initials: R
authors.lastname: Bonan
authors.forename: Keith G
authors.initials: KG
authors.lastname: Oldroyd
mesh_terms: D003097:Collateral Circulation / Q000502:physiology*; D003326:Coronary Circulation / Q000502:physiology*; D006801:Humans; D009203:Myocardial Infarction / Q000503:physiopathology*; D018919:Neovascularization, Physiologic / Q000502:physiology