Enhancement of noncoronary collateral circulation: the hypothesis of an alternative treatment for ischemic heart disease.

The internal thoracic arteries (ITAs) are a source of "noncoronary collateral circulation" (NCCC), or "noncoronary collateral blood flow" (NCCBF). The hypothesis herein is that enhancement of NCCC may represent an alternative means of myocardial blood supply: (1) Ligature of the ITAs creates a local hypertensive status and increases the perfusion pressure within the channels leading to the heart; (2) Myocardial ischemic stimulus diverts most ITA-related collateral flow to the heart rather than to the chest wall; (3) The ITAs may develop neo-collaterals owing to their ischemia-related plastic potential; (4) Angiogenic growth factor administration within the ITAs enhances neo-collateral development. These elements may pave the way for a new field of cardiovascular research aimed at enhancing NCCC as a new therapeutic option for ischemic heart disease.