Therapeutic Angiogenesis Using Local Perivascular and Pericardial Delivery

Therapeutic angiogenesis is a potential new treatment strategy that promises to grow new blood vessels to the ischemic myocardium in patients with ischemic heart disease. Despite its investigation in more than 550 patients with ischemic heart disease, the concept of clinical therapeutic angiogenesis remains a theoretic one with more questions than answers. This is due in part to a poor understanding of the fundamental mechanisms of adult collateralization and growth factor-induced angiogenesis, a poor understanding of the relative importance of large epicardial feeding collaterals versus intramyocardial neovascularization, and limited data concerning the best angiogenic cytokine, the best delivery modality, and the need for sustained exposure to that cytokine. This article discusses the available data on local perivascular delivery and pericardial delivery as they pertain to therapeutic angiogenesis. These delivery strategies have several characteristics that may make them ideal as adjuncts for coronary artery bypass surgery (local perivascular delivery) or in noninstrumented pericardium (pericardial delivery). They also have the theoretic advantage of affecting epicardial vessels and potentially promoting epicardial feeding collaterals.