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

BACKGROUND: One of most important mechanisms of coronary stent restenosis is neointimal hyperplasia. Although the process of neointima formation is not fully understood, a special role has been advocated for adherent platelets. Previous studies have shown a clear benefit with combined antiplatelet therapy such as aspirin plus ticlopidine in reducing the rate of thrombotic occlusions of stented vessels. The purpose of this study was to evaluate the effects of duration of antiplatelet regimens on coronary stent restenosis. METHODS: After successful placement of coronary artery stents in 222 patients, we performed follow-up coronary angiograms in 99 patients (42.3%). Forty-six patients were randomly assi-gned to receive aspirin and ticlopidine for four weeks (Group I: 54+/-9 years: M 38, F 8) and 48 patients for 6 months (Group II: 58+/-8 years: M 38, F 10). RESULTS: There were no significant differences in clinical and procedural variables or coronary lesion characteristics before and after stenting. At 6 months after stenting, minimal luminal diameter was 2.16+/-0.93mm in Group I and 2.04+/-1.07mm in Group II (p-0.57). Late lumen loss was 0.80+/-1.07mm in Group I and 0.92+/-1.11mm (p-0.58) in Group II. The stent restenosis rate of Group I at 28.3% and that of Group II at 29.2% were not statistically significant between the two groups (p-0.92). CONCLUSIONS: The therapeutic duration of combined antiplatelet regimen with aspirin and ticlopidine after coronary stent does not affect stent restenosis rate.
Aspirin* ; Coronary Vessels ; Follow-Up Studies ; Humans ; Hyperplasia ; Neointima ; Phenobarbital ; Stents* ; Ticlopidine*

Neointimal hyperplasia mainly develops within several months of coronary stent deployment, after which it stabilizes. Although it was widely accepted, particularly during the bare-metal stent (BMS) era, that in-stent restenosis (ISR) generally does not present as an acute coronary syndrome (ACS), but rather as a gradual recurrence of angina symptoms, recent data have shown that a substantial number of patients with ISR present as ACS. There has also been consistent postmortem evidence of plaque rupture secondary to atherosclerotic change within the neointima of a BMS. We report here a case of ACS in which intravascular ultrasound and optical coherent tomographic assessments revealed neointimal atherosclerotic change and ruptured plaque 10 years after BMS deployment.
Acute Coronary Syndrome ; Coronary Restenosis ; Humans ; Hyperplasia ; Neointima ; Recurrence ; Rupture ; Stents

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