Enhanced local intracoronary delivery of heparin with the Infiltrator (TM)catheter: A comparative study

The efficacy of local drug delivery in the treatment of coronary artery dis ease is limited by the relatively low delivery efficiency of the available devices. A unique local drug delivery device, the Infiltrator(TM) catheter (InterVentional Technologies, Inc.), has been designed specifically to enha nce efficiency by injecting drugs directly into the arterial wall through m icroports mounted on the balloon surface. The purpose of this study was to assess the efficiency of delivery of this device in the porcine coronary mo del and to compare it to a previously validated device, the hydrogel balloo n (Boston Scientific, Maple Grove, Minnesota). Studies were also performed to assess the pattern of intramural heparin deposition following delivery w ith the Infiltrator catheter and to assess the effect of the microports on vascular integrity. The efficiency of delivery was significantly greater with the Infiltrator c atheter than,vith the hydrogel balloon (4.5% vs. 0.08%; p = 0.02). Similarl y, the absolute amount of intramurally deposited heparin was greater with t he Infiltrator (111.3 +/- 38.5 units vs. 2.4 +/- 0.85 units; p = 0.02) desp ite the fact that more heparin was delivered with the hydrogel catheter. Hi stologic studies revealed characteristic discrete puncture channels in the vessel wall due to penetration of the microports. Other than this histologi c finding, there was no significant difference in the extent of architectur al disruption between the Infiltrator and conventional balloon inflations. Fluorescein-labeled heparin studies revealed heparin to be diffusely distri buted throughout the vessel wall immediately following delivery with the In filtrator. We conclude that the Infiltrator catheter's unique mechanism of delivery improves the efficiency of local drug delivery without excessive v essel wall trauma.