An in vitro flow model to study streaming during pelvic intra-arterial drug infusions.

Regional delivery of suitable drugs by intra-arterial infusion may offer a therapeutic advantage. High concentrations in the tumor are sought with reduced systemic toxicity. Adequate mixing of drug solutions with perfusing blood is essential to provide uniform distribution of drug to tumor-bearing tissue distal to the infusion site. Using a glass model of the iliofemoral and pelvic arteries, we have demonstrated that a streaming phenomenon occurs. Laminar "streamers" of slowly infused drug solution originate at the catheter tip and proceed nonuniformly into distal arterial branches. The intensity of streaming and the pattern of distribution are highly sensitive to catheter tip placement and quite unpredictable. The consequence of regional therapy under streaming conditions is severe maldistribution of drug in the infused tissues with potentially high levels delivered to normal tissues and simultaneous subtherapeutic levels delivered to tumor. Our in vitro model can be used to test appropriate infusion techniques that enhance mixing such as pulsed infusions and novel catheter designs.