Preventive effects of the heparin-coated stent on restenosis in the porcine model

The coronary stent reduces acute coronary arterial occlusion and late reste nosis during and after coronary intervention. However, stent thrombosis and restenosis are still major limitations in the widespread use of the corona ry stent. Local drug delivery using the heparin-coated stent may be a new a pproach, which reduces the incidence of stent thrombosis and restenosis. In order to evaluate the effects of the heparin-coated stent on stent resteno sis, heparin coated stents were compared with control stents in a porcine c oronary stent restenosis model. Stent overdilation injury (stent:artery = 1 .3:1.0) was performed with bare Wiktor stents (group I, n = 10) and heparin coated Wiktor stents (group II, n = 20; HEPAMED, Medtronics) in porcine co ronary arteries. Follow-up quantitative coronary angiography (QCA) was perf ormed at 4 weeks after stenting, and histopathologic assessments of stented porcine coronary arteries were compared in both groups. On QCA, percent diameter stenosis was significantly higher in group I than in group II (16.3% +/- 6.62% vs. 9.6% +/- 5.06%, P < 0.05). The injury scor e of stented porcine coronary arteries was the same in both groups (1.26 +/ - 0.23 vs. 1.20 +/- 0.22). The area of pathologic stenosis of the stented a rteries was higher in group I than in group II (41.6% +/- 12.5% vs. 27.1% /- 9.9%, P < 0.005). The neointimal area was higher in group I than in grou p II (4.58 +/- 1.41 mm(2) vs. 2.57 +/- 1.07 mm(2), P < 0.05). By immunohist ochemistry, the proliferating cell nuclear antigen (PCNA) index was higher in group I compared with group II (11.2% +/- 6.75% vs. 6.3% +/- 4.14%, P < 0.05). The heparin-coated stent is effective in the prevention of late coro nary stent restenosis in a porcine coronary stent restenosis model. This ma y be related to the inhibition of neointimal cell proliferation, Cathet. Ca rdiovasc. Intervent 48:324-330, 1999. (C) 1999 Wiley-Liss, Inc.