Therapeutic site selection is important for the successful development of collateral vessels

Several clinical trials of angiogenic therapy for the treatment of peripheral arterial diseases have been conducted. In these trials, angiogenic factors or cells were delivered by intra-arterial or intramuscular injection. However, wide dispersion of the delivered substances to distal areas occurs with intra-arterial injections, and intramuscular injections usually involve broad, multiple injections to the ischemic limb; therefore, both methods might fail to achieve appropriate target site delivery for collateral development. On the basis of the conclusions of this study, accurate delivery of angiogenic substances to the appropriate site could markedly enhance the therapeutic efficacy of human angiogenic therapy.