No abstract available.
Hyperplasia* ; Neointima* ; Thalidomide*

No abstract available.
Hyperplasia* ; Neointima* ; Thalidomide*

The purpose of this study was to investigate the patency rates and the histologic findings of neoendothelialization according to the length of implanted polytetrafluoroethylene (PTFE) with an internal diameter of 3mm. Under the operating microscope, grafts of 8 and 24mm in length were implanted in the right carotid arteries of thirty rabbits by interrupted end-to-end microanastomosis. They were divided into two groups according to the length of implanted PTFE. Each group had fifteen rabbits. All implanted grafts were 25micro meter in fibril length and 0.39mm in wall thickness. Three grafts per group were harvested at 1, 2, 4, 8, and 12 weeks after implantation and all grafts were observed for patency rates and the histologic findings with a light microscope and scanning electron microscope. In conclusion, there was no difference in patency rates according to the length of implanted PTFE. However, the formation of neointima and subintimal tissue was delayed and incomplete in the longer implanted PTFE group.
Carotid Arteries ; Neointima ; Polytetrafluoroethylene* ; Rabbits ; Transplants

The purpose of this study was to investigate the patency rates and the histologic findings of neoen- dothelialization according to the length of implanted polytetrafluoroethylene (PTFE) with an internal diameter of 3 mm. Under the operating microscope, grafts of 8 and 24 mm in length were implanted in the right carotid arteries of thirty rabbits by interrupted end-to-end microanastomosis. They were divided into two groups according to the length of implanted PTFE. Each group compised fifteen rabbits. All implanted grafts were 25 pm in fibril length and 0.39 mm in wall thickness. Three grafts per group were harvested at 1, 2, 4, 8, and 12 weeks after implantation respectively and all grafts were observed for patency rates and the histologic findings with light microscope and scanning electron microscope. In conclusion, there was no difference in patency rates according to the length of implanted PTFE and histologically the formation of neointima and subintimal tissue was delayed and incomplete in longer implanted PTFE.
Carotid Arteries ; Neointima ; Polytetrafluoroethylene* ; Rabbits ; Transplants

Neointimal hyperplasia is the main mechanism of stent restenosis. Therefore, drug-eluting stents have replaced bare metal stents because there is less neointima and scar formation. Recently, some cases of stent restenosis after using a bare metal stent were found to involve calcification, not neointimal hyperplasia, and regarded as de novo atherosclerosis. We report unusual circular calcification inside a drug-eluting stent, which we called neointimal calcification.
Atherosclerosis ; Cicatrix ; Drug-Eluting Stents ; Hyperplasia ; Neointima ; Stents

Neointimal hyperplasia is the main mechanism of stent restenosis. Therefore, drug-eluting stents have replaced bare metal stents because there is less neointima and scar formation. Recently, some cases of stent restenosis after using a bare metal stent were found to involve calcification, not neointimal hyperplasia, and regarded as de novo atherosclerosis. We report unusual circular calcification inside a drug-eluting stent, which we called neointimal calcification.
Atherosclerosis ; Cicatrix ; Drug-Eluting Stents ; Hyperplasia ; Neointima ; Stents

BACKGROUND: Restenosis remains one of major clinical problems in the coronary intervention. The effects of local radiation using radioactive balloon loaded with Ho-166 on coronary restenosis in the porcine model were observed. METHODS: Overdilation injury was performed in porcine coronary arteries using control balloon [Group I, n=, left anterior descending artery (LAD)=, left circumflex artery (LCX)=, right coronary artery (RCA)=] and Ho-166 loaded polyurethane-coating balloon [Group II; n=0, 21.98.1 mCi (20 Gy at 0.5 mm in depth), LAD=, LCX=, RCA=] at 5 atm for 3 min. Follow-up quantitative coronary angiogram (QCA) and histopathologic findings were compared at 4 weeks after balloon injury between two groups. RESULTS: Acute or late thrombotic arterial occlusion was not observed in both groups. Diameter stenosis measured by QCA was not different between two groups (Group I: 11.61.6%, II: 7.68.4%, P=.44). On histopathologic study, injury score, external and internal elastic lamina area, and media area were not different between two groups. Neointimal area and histopathologic area stenosis were significantly higher in Group I (0.320.86mm2, 20.677.01%) than those of Group II (0.150.26mm2, 12.032.44%). By immunocytochemistry, proliferating cell nuclear antigen indices in neointima and media were 8.244.44%, 7.972.46% in Group I, and 7.172.25%, 5.471.44% in Group II, which were not different between two groups(P=.587, 0.089). CONCLUSION: Local radiation using Ho-166 balloon is effective in reducing neointimal proliferation in a porcine model.
Arteries ; Constriction, Pathologic ; Coronary Restenosis* ; Coronary Vessels ; Follow-Up Studies ; Immunohistochemistry ; Neointima ; Proliferating Cell Nuclear Antigen

PURPOSE: The purpose of this study was to evaluate basic experimental data for the clinical application of a self-expandable stainless steel intravascular Hanaro spiral stent. MATERIALS AND METHODS: For evaluation of thephysical properties of the Hanaro stent, hoop strength, radioopacity, longitudinal flexibility, and foreshortening were measured. Twelve intravascular Hanaro spiral stents were placed in the infrarenal abdominal aorta (n=6) and comon iliac artery (n=6) in six mongrel dogs. Angiography and light microscopic examination were performed after one, two and eight months of placement of the stents. RESULTS: The stent had good radioopacity and was deployed with minimal foreshortening. Hoop strength of a 6mm-interval bend was found to be superior to that of 8mm- and 10mm-bend stent. On angiography the patency rate and thrombosis rate were 100% and 0% in the abdominal aorta and 50% and 50% in the common iliac artery, respectively. Minimal corrosion was seen in all stents, and they appearedto be biocompatible. The stent wires were covered with well-developed neointima which after one month had mostly fibroblast and collagen tissue; the thickness of the neointima increased gradually during a period of eightmonths. At the end of that period, collagen fibres in the neointima were denser and showed a more paralled configuration than at one month. CONCLUSION: The Hanaro stent has good physical properties and also has a high patency rate, and good biocompatibilities. The stent may therefore be reliably and safely deployed in the humanvascular system.
Angiography ; Animals ; Aorta, Abdominal ; Atherosclerosis ; Collagen ; Corrosion ; Dogs ; Iliac Artery ; Neointima ; Pliability ; Stainless Steel ; Stents ; Thrombosis

PURPOSE: To evaluate the effect of dexamethasone(DM) and polyurethane(PU)-coated nitinol stent on neointimal formation in the canine great vessels. MATERIALS AND METHODS: Thirty-six nitinol wire stents were implanted in the abdominal aorta and inferior vena cava(IVC) of six dogs. In each animal, six different types of stent (NC, non-coated; PU, polyurethane coated; DM, DM and polyurethane coated) were serially positioned in permutationally possible order in the aorta below the renal arteries and in the IVC below the renal veins. For DM stent an in-vitro drug release test was performed to determine the stability of DM release. The thickness of the intima and media of the aorta and of the intima of the IVC were measured three (n=3) or six months (n=3) after stent placement at and between the wires. RESULTS: In the in-vitro study, 25% of DM was released during the first week, and the subsequent release rate was 3 microgram/day for 6 months. The intima-to-media ratio of DM-stented aorta was less than in aortas where PU or NC stents were used (p<0.05). The neointima thickness of DM stent in the IVC was less than that of PU stent (p<0.05). These differences were less prominent between the wires than at them, and there was no significant difference between the three-and six-month groups (p>0.05). CONCLUSION: In this canine great vessel model, newly designed DM-coated nitinol stent decreased neointimal formation.
Animals ; Aorta ; Aorta, Abdominal ; Dexamethasone* ; Dogs ; Neointima ; Polyurethanes ; Renal Artery ; Renal Veins ; Stents*

PURPOSE: To evaluate changes of residual aneurysms according to the size of aneurysmal neck andthrombogenicity of a tungsten coil after incomplete embolization of experimental lateral aneurysms. MATERIALS AND METHODS: Eleven experimental lateral aneurysms with different aneurysmal neck size were created in the commoncarotid arteries of mongrel dogs. They were then divided into narrow-neck(n=3), wide-neck(n=6) and spontaneouslythrombosed control(n=2) groups. After confirmation of aneurysmal patency, incomplete embolizations of varyingdegrees (about 30% to near total occlusion) were performed using 5mm-diameter tungsten coils. Angiography wasperformed immediately before and after, and one and six weeks after embolizations. The size of residual aneurysmwas measured on each angiogram. After the last angiography, embolized aneurysms were excised and examined underlight and electron microscopes. RESULTS: On angiograms obtained 6 weeks after embolization, all residual narrowneck aneurysms were completely occluded, whereas in those with a wide-neck, therre was either no change (n=4) or aslight increase in size(n=2). On light microscopy, all narrow-neck aneurysms showed total organized fibrosis whileall control aneurysms and half those with a wide neck showed unorganized thrombi. The embolized group showed ahigher degree of organization in the aneurysmal cavity than did the control group. Neointima formation was seen inall embolized aneurysms, but no aneurysm showed foreign body reaction. On electron microscopy, uniform thicknessof plasma coatings was noted on the surface of the tungsten coils. CONCLUSION: A wide-neck residual aneurysm maypersist or increase in size, while one with a narrow-neck can be thrombosed after incomplete embolization withtungsten coils in a lateral aneurym. Careful consideration might be necessary in the embolization of wide-neckaneurysms. With plasma coatings on its surface and organized fibrosis, tungsten coil can be an useful forembolization of an aneurysm.
Aneurysm* ; Angiography ; Animals ; Arteries ; Dogs* ; Fibrosis ; Foreign-Body Reaction ; Microscopy ; Microscopy, Electron ; Neck ; Neointima ; Plasma ; Tungsten*