772-2 Local Intracoronary Delivery of Heparin and of a Somatostatin Analogue (Octreotide) Following Angioplasty in Man: Evaluation of Efficacy of Delivery by Radio-Isotopic Technique

In 37 patients (28 men, 58±10 years) following conventional PTCA heparin (H) (n=37) and Octreotide (O) (n=10) was infused through the Dispatch™ (Scimed) at the site of angioplasty. Mean drug infusion time was 30±7min (range: 7–39min). A volume of 16±6ml (range: 1.4–23.4mil corresponding to 1660±656 IU H and 0.39±0.02 μg O was infused with a mean pressure of 110±48mmHg. Radio-isotopic studies with infusion of technetium labelled H (Tc-99m H; n=2) or of indium labelled O (In-111 O; n=5) were performed to assess efficacy of local drug delivery. During infusion a linear accumulation was observed for Tc-99m Hand In-111 O (linear fitting: H: r=0.97±0.02; O: r=0.98±0.02) followed at infusion stop by a biexponential washout (biexponential fitting: H; r=0.96±0.02; O: r=0.98±0.02). Local retention time, defined as 5 concentration half-lives and derived from the 2nd slow washout phase, thought to reflect tissular washout, was for H 18±2 h and for a 7±3 h. Of the totally infused dose for H 6.8% and 0.5% (123 and 11 IU; 644 and 58 Itg) and for O 0.3%±0.2% (0.55±0.37 μg) remained at the site of delivery. In conclusion administration of radiolabelled drugs allows to assess local pharmacokinetics and to quantify local drug retention-time and local retained amount of drug.