Laser driven short-term thermal angioplasty: Enhancement of drug delivery performance by heating with tension

To enhance drug delivery performance of drug eluting balloon (DEB) against re-stenosis, we have proposed a heating drug delivery during balloon dilatation using our laser driven short-term thermal angioplasty which may realize to suppress surrounding thermal injury. We studied an influence of vessel dilatation parameters on the heating drug delivery. These parameters were classified into two different forces, that is, circumferential tension and inter-luminal pressure. We think these parameters were not able to determine only by balloon pressure. The circumferential tension with 0 - 30 mN/mm² was added to a porcine carotid artery using an automatic stage. Various temperature solutions with 37, and 70°C of hydrophobic fluorescent Rhodamine B with 3 μg/ml in concentration were dropped on pig carotid wall. We measured a defined drug delivery amount as well as delivery depth by a microscopic fluorescence measurement on the cross section of the solution delivered vessel. In the case of 37°C, we found the intima surface drug amount with 7 mN/mm² was increased as 10-20 times as other tension cases. On the other hand, at 70°C, we found the optimum tension with 30 mN/mm². We found the drug delivery enhancement might be related to the change of super microscopic surface structure of the vessel. We predict that the collagen thermal denaturation of the vessel wall might play important role to the drug delivery.