793-5 Reducing Platelet Adhesion Following Angioplasty: The Effects of Platelet Encapsulated 1I0prost Delivered Locally or Intravenously

Abstract

Reducing platelet (plt) deposition following balloon angioplasty may reduce immediate procedural complications and limit subsequent neo-intimal hyperplasia. We electro-encapsulated the stable prostacyclin analogue, iloprost (IL) (which inhibits plt-plt interactions without affecting plt adhesion to collagen), into autologous plts and studied plt recruitment following balloon injury. Pigs (n = 16) underwent bilateral carotid angioplasty after pre-injection of 111 Indium labelled plts and were randomised at the time of angioplasty according to method of plt delivery:- Group 1) IL plts delivered locally using a double balloon catheter 2) IL plts as an iv bolus at the time of angioplasty 3) Sham electroporated plts delivered locally 4) Sham plts delivered locally with the addition of free IL to the suspension (in an amount equivalent to twice that present in the IL plts). Animals were sacrificed at 1.5 hrs post angioplasty and sections (n = 2 each artery) were classified by histology into minimal (M) or deep injury (D) (ruptured internal elastic lamina) M (n) D (n) Sham local delivery 30 ± 2 (3) 110 ± 20 (11) Sham + free IL local delivery 43 ± 9 (9) 62 ± 11 (7) * , + IL iv bolus 11 ± 0.2 (2) 58 ± 12 (7) * , + IL local delivery 21 ± 4 (5) 14 ± 1 (11) * * p < 0.05 treatment vs sham local delivery + p < 0.05 treatment vs IL local delivery We conclude that platelet adhesion at sites of deep arterial injury is reduced by IL delivered via encapsulated plts, immediately following balloon injury. Maximum beneficial effect is seen when plts are delivered locally.