Effects of intravenous and intra-arterial infusions of prostaglandin E₁ on canine hindlimb blood flow distribution

Prostaglandin E₁ (PGE₁) has been used clinically in the treatment of ischemic peripheral vascular disease. However, the preferred route of administration and its influence on the distribution of blood flow to the skin, muscle, bone, and arteriovenous anastomoses (AVAs) have yet to be established. Bilateral femoral arterial blood flow was measured electromagnetically in 10 anesthetized adult mongrel dogs (mean weight 16.5 kg). The distribution of femoral arterial flow to the skin, muscle, bone, and AVAs was determined with use of femoral intra-arterial injections of radioactively tagged microspheres (15 ± 1 μ) before, during, and 1 hour after 20 minutes of intravenous and intra-arterial infusions of PGE₁ at 0.1 μg kg^-1 min^-1. Intra-arterial infusions caused a significant (P <0.003) increase in femoral arterial flow (462 ± 58 ml·min^-1), which was sustained throughout the infusion. The distribution of flow to the skin increased significantly (P <0.01) to 24.1 ± 2.1%, whereas that through AVAs was significantly (P <0.05) decreased 3.2 ± 0.9%. Femoral arterial blood flow did not change during intravenous infusions; however, there was a significant (P <0.01) reduction in the distribution to muscle (41.1 ± 10.5%) associated with a significant (P <0.02) increase in distribution through AVAs (30.8 ± 11.5%). These data demonstrate the superiority of intra-arterial infusion over intravenous infusions of PGE₁ in the canine hindlimb. There was a significant increase in femoral arterial blood flow with increased distribution to the skin and decreased shunting. Femoral arterial blood flow did not change during intravenous infusions; however, a reduction in the distribution of flow to the muscle was accompanied by an increase in shunting.