Feasibility and efficacy of locally delivered enoxaparin via the Channeled Balloon catheter on smooth muscle cell proliferation following balloon injury in rabbits.

Overview

To determine the potential utility of local treatment of enoxaparin on restenosis, four groups of rabbits underwent balloon injury of bilateral iliac arteries with the Channeled Balloon (balloon/artery = 1.1), followed by assigned treatment (5 controls received local saline, 7 local-treatment rabbits received a one-time local delivery of 10 mg/kg of enoxaparin, 5 systemic-treatment rabbits received 10 mg/kg of enoxaparin subcutaneously once daily for 1 wk, and 5 combined-treatment rabbits received both local and systemic enoxaparin). The percentage of nuclei positive for proliferating cell nuclear antigen/microns2 of media 1 wk later was 1.97 +/- 2.01 for the control group, 2.68 +/- 2.52 for the local group, 0.22 +/- 0.32 for the systemic group, and 0.07 +/- 0.09 for the combined group (P < 0.0001 by Kruskal-Wallis test, with P < 0.05 for combined treatment group vs. controls or local treatment group and systemic vs. local groups). Feasibility study with 3H-enoxaparin showed intramural retention of 0.1-0.2% of locally delivered amount for 24 h. We conclude that one-time local delivery of enoxaparin following angioplasty is ineffective in inhibiting medial smooth muscle cell proliferation, most likely due to low efficiency. Only sustained treatment resulted in significant reduction.