 Coronary artery disease CAD is the leading cause of death in industrialized countries. Current therapies for restoration of coronary flow are percutaneous coronary intervention PCI or surgical revascularization. However, inherent to them are procedure-related risks and the fact that CAD progression is not prevented. Additionally, up to one fourth of all CAD patients are not amenable to standard revascularization therapies. Thus, there is a need for alternative therapies. Coronary collaterals as natural bypasses are anastomoses without an intervening capillary bed between portions of the same coronary artery or between different coronary arteries. The coronary collateral circulation is prevalent in humans and in CAD the amount of collateral flow is directly related to infarct size, all-cause- and cardiac mortality. Thus, the goal is to promote collateral function in the sense of prophylactic myocardial salvage. 