Effects of Ramiprilat-Coated Stents on Neointimal Hyperplasia, Inflammation, and Arterial Healing in a Porcine Coronary Restenosis Model

BACKGROUND AND OBJECTIVES: The renin-angiotensin-aldosterone system has been implicated in the pathogenesis of neointimal hyperplasia, and a role for angiotensin II in the migration and proliferation of vascular smooth muscle cells in restenotic lesions has been proposed. The aim of this study was to determine the anti-proliferative and anti-inflammatory effects of ramiprilat-coated stents in a porcine coronary overstretch restenosis model. SUBJECTS AND METHODS: Pigs were randomized into two groups in which the coronary arteries {16 pigs (16 coronaries in each group)} had a 3.0x17 mm ramiprilat-coated MAC stent or a 3.0x17 mm control MAC stent (AMG, Munich, Germany) implanted with oversizing (stent-to-artery ratio, 1.3 : 1) in porcine coronary arteries, and histopathologic analysis was assessed 28 days after stenting. RESULTS: There were no significant differences in the injury and inflammation scores between the two groups (1.20+/-0.43 vs. 1.23+/-0.57, p=0.8; and 1.21+/-0.39 vs. 1.25+/-0.49, p=0.6, respectively). Within the neointima, most inflammatory cells were lymphohistiocytes. Significant positive correlations existed between inflammatory cell counts and the neointima areas (r=0.567, p<0.001), and between inflammatory cell counts and the percent area stenosis (r=0.478, p<0.001). There was no significant difference in the inflammatory cell counts normalized to the injury (110+/-89 vs. 123+/-83, p=0.4) and fibrin scores (0.15+/-0.06 vs. 0.17+/-0.07, p=0.8) between the 2 groups. There were trends toward a smaller neointima area (1.06+/-0.51 mm2 vs. 1.28+/-0.35 mm2, p=0.083) and a smaller percent area stenosis (18.9+/-8.7% vs. 21.8+/-7.2%, p=0.088) in the ramiprilat-coated stent group. CONCLUSION: Although the ramiprilat-coated stent did not show significant inhibitory effects on neointimal hyperplasia, the ramiprilat-coated stent showed good effects on the inflammatory reaction and arterial healing similar to the control stent in a porcine coronary restenosis model.

Effect of a Dual Drug-Coated Stent With Abciximab and Alpha-Lipoic Acid in a Porcine Coronary Restenosis Model

BACKGROUND AND OBJECTIVES: The aim of this study was to examine the anti-proliferative and anti-inflammatory effects of a stent coated with abciximab and alpha-lipoic acid (ALA) in a porcine coronary overstretch restenosis model. MATERIALS AND METHODS: A total of 10 pigs were randomized into two groups (10 pigs, 10 coronaries in each group) in which the coronary arteries were stented with a dual-coated stent and a bare metal stent (control) by randomization. Stents were deployed with oversizing (stent/artery ratio 1.3 : 1) in the porcine coronary arteries, and histopathology was assessed 28 days after stenting. RESULTS: There was no significant difference in the injury score between the two groups. In the neointima, the lymphohistiocyte count was significantly lower in dual-coat stent group compared with the control stent group (120+/-85 cells vs. 159+/-80 cells, p=0.048). There was no significant difference in the fibrin score between the two groups (0.16+/-0.34 in the dual-coated stent group vs. 0.25+/-0.48 in the control stent group, p=0.446). The neointima area was not significantly different between both groups (1.55+/-0.8 mm2 in dual-coated stent group vs. 1.40+/-0.86 mm2 in the control stent group, p=0.447). CONCLUSION: Although the dual-coated stent with abciximab and ALA showed no significant difference in inhibition of neointimal hyperplasia when compared with the bare metal stent, it was associated with a reduced inflammatory reaction when compared with the control stent in a porcine coronary restenosis model.