Porous balloon delivery of low molecular weight heparin in the dog coronary artery.

Abstract

The aim of this experimental study was to assess the safety of local delivery of low molecular weight heparin via a porous balloon in the canine coronary artery. In 16 mongrel dogs, percutaneous transluminal coronary angioplasty was performed. In addition, eight of the dogs were given 4 ml Clivarin (1500 IU) delivered locally into the coronary artery immediately after dilatation. The animals were killed after 3 or 14 days. In the animals with local administration, the results of histopathology after 3 days showed the findings to be heterogeneous with marked disruption of the internal elastic lamina in all animals, and varying degrees of medial haemorrhage, medial necrosis, perivascular haemorrhage and signs of myocardial necrosis. Similar changes, but of lesser severity, were present in the animals treated with balloon dilatation only. After 14 days, the severity of vascular and perivascular alterations (medial haemorrhage, perivascular haemorrhage, thrombus formation) was significantly lower in the local delivery group (P < 0.05), but disruption of the internal elastic lamina, as a marker of the initial trauma, was present in all the animals. The presence of residual intracoronary thrombus was only seen in the PTCA group without local delivery. In this safety study, both groups showed pronounced alterations in the vessel wall 3 days following percutaneous transluminal coronary angioplasty. This changed 14 days following percutaneous transluminal coronary angioplasty when intramural injection of Clivarin resulted in a marked decrease of residual thrombus and medial as well as perivascular haemorrhage. Although the additional vessel trauma by the drug delivery technique did not result in increased complications, a careful approach with this potentially harmful procedure is essential.