The human coronary collateral circulation: development and clinical importance

Area of Science:

• Cardiovascular Science
• Medical Research

Background:

• Coronary collaterals provide alternative blood supply to the heart muscle during ischemia.
• Human coronary collateral circulation is notably well-developed compared to other species.
• Preformed collaterals protect against ischemia in 20-25% of individuals without coronary artery disease (CAD), influenced by low heart rate and absence of hypertension.

Purpose of the Study:

• To investigate the role and therapeutic potential of coronary collateral circulation in patients with CAD.
• To explore arteriogenesis as a treatment strategy for CAD patients who cannot undergo revascularization.

Main Methods:

• Review of existing literature on coronary collateral function and determinants.
• Analysis of the impact of collateral supply on myocardial infarct size and patient prognosis.
• Identification of potential therapeutic approaches to promote collateral growth (arteriogenesis).

Main Results:

• In patients with CAD, collateral arteries preventing ischemia during brief occlusion are found in about one-third of individuals.
• Collateral flow sufficient to prevent ischemia is one-fifth to one-fourth of normal flow.
• Myocardial infarct size is determined by occlusion time, area at risk, and inverse collateral supply.
• Well-developed collaterals in CAD patients mitigate infarcts and improve survival.
• Approximately 20% of CAD patients are not candidates for percutaneous coronary intervention or bypass grafting.

Conclusions:

• Therapeutic promotion of collateral growth (arteriogenesis) is a valuable strategy for CAD patients ineligible for revascularization.
• Arteriogenesis aims to enhance large, conductive collateral arteries.
• Potential arteriogenic approaches include granulocyte colony-stimulating factor, exercise training, and external counterpulsation.