ABSTRACT
Objective:To investigate the effect of rapamycin eluting coronary stent for inhibition of neointimal hyperplasia in diabetic porcine model.Methods:There were two groups in this study. Diabetic group, n=12, diabetic porcine model was established by a single dose of streptozotocin, and rapamycin eluting coronary stents were randomly implanted into 2 of the major epicardial coronary arteries. Control group, n=12, with non-diabetic porcine. The degree of neointimal hyperplasia evaluated by coronary angiography, intravascular ultrasound (IVUS) and histopathology were compared between two groups respectively at 6 months of the event. Results:The distribution of vessels received stents, reference vessel diameters and post-procedural minimal luminal diameter were comparable between two groups. All animals received angiographic follow-up at 6 months of time. In Diabetic group, the degree of stent stenosis (35.6%±9.2% vs. 7.9%±3.1%,P<0.001), late lumen loss (0.32±0.09 mm vs. 0.09±0.04 mm,P<0.001), the thickness of neointima by IVUS examination (0.35±0.12 mm vs. 0.11±0.08 mm,P<0.05) and area stenosis by IVUS (1.29±0.51 mm~2 vs. 0.26±0.11 mm~2, P<0.001); and histopathological examination (1.24±0.76 mm~2 vs. 0.19±0.08mm~2, P<0.05) were significantly higher than those in Control group. Conclusion: The neointimal hyperplasia after rapamycin eluting stent implantation was significantly severe in the diabetic porcine models than those in non-diabetic ones.
ABSTRACT
Objective To study the effect of myocardial infarction induced by distal left ascending artery occlusion on left ventrieular(LV) synchronism. Methods Routine echocardiography and vector velocity imaging were performed within 2 hours before and 7-14 days after myocardial infarction by occluding distal left ascending coronary arteries in experimental pigs. Routine eehocardiographie parameters of LV, including end diastolic and systolic diameters, volumes, and spherical indexes were measured or calculated. Six segmental peak systolic velocity, strain and strain rate were compared between pre- and post-myocardial infarction. Results After myocardial infarction, LV end diastolic, end systolic long diameter and end systolic volume increased with decreased ejection fraction. With the 6 segmental systolic velocity, strain and strain rate significantly reduced,the mean 6-segmental time to peak strain rate delayed significantly. Conclusions Abnormal synchronism after myocardial infarction may aggravate LV systolic dysfunction.