Coronary Collaterals: A Comprehensive Review

Area of Science:

• Cardiovascular Medicine
• Physiology
• Biomedical Engineering

Background:

• Coronary collateral circulation comprises pre-existing arterial connections that enlarge during coronary stenosis.
• The review examines the developmental, anatomic, and regulatory aspects of collateral growth.

Purpose of the Study:

• To review the developmental and anatomic basis of coronary collateral circulation.
• To summarize factors modulating collateral growth.
• To appraise assessment methods and propose a function-first framework for clinical integration.

Main Methods:

• Literature review tracing developmental and anatomic basis.
• Appraisal of assessment methods including visual angiography, collateral flow index, intracoronary electrocardiography, cardiac MRI, and PET.
• Analysis of therapeutic strategies and role of AI.

Main Results:

• Stronger collaterals correlate with smaller infarcts, less microvascular injury, and better ventricular recovery in acute infarction and chronic total occlusion.
• Anatomic assessment alone may not reflect true perfusion.
• Artificial intelligence offers potential for standardized interpretation and function estimation.

Conclusions:

• A function-first approach to assessing coronary collateral circulation is superior to visual grading.
• Therapeutic strategies include exercise, counterpulsation, and emerging metabolic/biologic options.
• Integrating collateral assessment into routine care using a function-first framework is proposed.