PROBUCOL DECREASES NEOINTIMAL FORMATION IN A SWINE MODEL OF CORONARY-ARTERY BALLOON INJURY - A POSSIBLE ROLE FOR ANTIOXIDANTS IN RESTENOSIS

Background. Restenosis after percutaneous transluminal coronary angioplasty is the major limitation of the long-term success of this procedure. The process of restenosis is similar to an accelerated form of atherosclerosis. Thus, therapeutic interventions that limit the progression and initiation of atherosclerosis may be beneficial in the treatment of restenosis. One such intervention is the antioxidant drug probucol, which has demonstrated benefit in animal models of atherosclerosis. Methods and Results. Twenty-six female domestic swine were divided into three study groups (control, n=9; low-dose probucol, n=9; high-dose probucol, n=8) before oversized balloon injury of the left anterior descending and left circumflex coronary arteries. Probucol (1 g/d, low-dose group; 2 g/d, high-dose group) was administered 2 days before balloon injury and was continued until the swine were killed 2 weeks after balloon injury. Morphometric analysis of the injured arteries included the intimal area (square millimeters), maximal intimal thickness (millimeters), and residual lumen (ratio of luminal to intimal plus luminal area). Treatment with high-dose probucol significantly reduced neointimal formation compared with control animals (decreases of 36% in intimal area, P=.007; 20% in maximal intimal thickness, P=NS; and an increase of 15% in residual lumen, P=.02). Conclusions. The major finding of this study is that the antioxidant drug probucol reduces neointimal formation after oversized balloon injury in a swine model of restenosis. This suggests that active oxygen species may play a role in restenosis.