Objective To observe the effects of the chronic adventitia injury on the vasoconstriction of the rat carotid artery. Methods A non-occlusive silicone collar was positioned around the right carotid artery of rats. Blood flow and vascular reactivity to 5-HT were examined, and both carotids were harvested for morphometry at day 3,7 and 14 after operation. Results In the early stage of advenfitia injury induced by positioning a silicone collar around file rat carotid artery, there appeared the characteristic histological changes of chronic vasospasm in collared artery, such as the reduction of the luminal area for （12.15±2.29）% at day 3 after operation （P =0.003 ） and （45.17±3.84）% at day 7 （P 〈 0.001 ）] ,corrugation of the internal elastic lamina,medial thickening up to [ （23.04±5.96）% at day 3 （P =0.009）, （61.65±10.32）% for day 7 （P 〈 0.001 ）] ,the reduction of the blood flow and the increase of vascular reactivity to 5-HT when compared to con- tralateral arteries. Two weeks after collar placement, the vascular wall remodeling was observed in injured artery, such as the medial thickening for [（31.52±4.56） %,P =0.012] and a diffuse intimal hyperplasia,the reduction of the lunfinal area [（37.17±4.57）% （P 〈 0.001）] and the carotid artery blood flow. The average neointima area was （0.19±0.05） rom2 in collared arteries. The vascular reactivity to 5-HT came back to the normal level. Conclusions Collar-induced advenfitia injury caused the enhancement of vascular contractility and the neointima formation. The change of vascular contractility appeared before the formation of neointima.

Objective: To explore the influencing factors of slow blood flow phenomenon after emergency percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Methods: Clinical and PCI angiographic data of 488 patients, who were diagnosed as AMI and received primary PCI in our hospital from Jan 2010 to Jun 2011, were retrospectively analyzed. Patients were divided into slow blood flow group (n=51, TIMI flow ≤ grade 2) and normal flow group (n=437, TIMI flow= grade 3). Their clinical characteristics between two groups were compared. Results: Compared with normal flow group, there were significant reductions in percentages of thrombus aspiration (75.3% vs. 60.8%) and application of platelet glycoprotein IIb/IIIa receptor antagonist (81.7% vs. 68.6%) during PCI, and significant rise in total length of implanted stents [(31.8±12.2) mm vs. (35.7±12.0) mm] in slow blood flow group, P<0.05 all. Multi-factor Logistic regression analysis indicated that percentages of thrombus aspiration during PCI and total length of stents were independent influencing factors for slow blood flow (P<0.05 both). Conclusion: Percentages of thrombus aspiration and total length of stents during PCI are independent influencing factors for slow blood flow.