| BackgroundIn recent years, onset of cerebral infarction showing a younger trend, the reason of i nfarction incidence, its risk factors and the internal mechanism is the focus of recent research.When the feeding artery were severe stenosis or occlusion, the establishment of collateral circulation can increase cerebral blood flow and prevent the occurrence of cerebral ischemia, a network of cerebral collateral circulation establishment and its development take an extremely important role in prevention and treatment of ischemic cerebrovascular disease. Small vessel infarction is a very complex phenomenon, and its internal mechanism is a research hotspot in recent years. Most current research focuses on the clinical features, factors and treatment methods of large vessels infarction, but for some unexplained cerebral infarction, such as studies of cerebral infarction after chronic cerebral artery occlusion was relatively rare, the studies of young small vessel infarction was less, which causing great restrictions to elucidating the mechanism of cerebral infarction and clinically targeted therapy of small blood vessels. Patients in this study were all with unilateral middle cerebral artery M1segment chronic occlusion, and among whom proportions of patients with small vessel infarction was high, so it can carry out research on the characteristics of small vessels infarction. At the same time, What kind of relationship between the collateral circulation and small vessel infarction in these patients? Previous conclusions about the relationship between the traditional risk factors and cerebrovascular collateral circulation were inconsistency, so for patients with unilateral middle cerebral artery M1segment chronic occlusion, what kind of relationship between its risk factors and the establishment of collateral circulation? That is the issue this study explores.ObjectiveTo explore the relationships between the cerebral infarction and cerebral vascular risk factors, and it between cerebral vascular risk factors and collateral circulation establishing and in young patients with cerebral infarction after their initial segment of unilateral MCA-M1slowly occlused.MethodsA study was conducted to analyze90patients admitted to the internal medicine-neurology of our hospital with simple slow MCA-M1occlusion from July2009to June2013,48males and42females, mean44.6±9.7years, who were devided into two groups:there were50patients with fresh infarction group, those without infarct40people wre in non-infarction group; We analysised the relationship between the new cerebral infarction and cerebral vascular risk factors, and it between the new cerebral infarction with the collateral circulation.Results1. The age distribution trend of90cases of patients with MCA-M1chronic total occlusion was that the50-59age group were most, accounted for37.8%, and the age group of20-29were least, accounted for8.9%. There was no significant difference between two groups of patients with and without cerebral infarction in age distribution,χ2=4.394, P>0.2.2. There is no significant correlation between risk factors as high cholesterol, diabetes, smoking, hypertension, homocysteine and cerebral infarction.3. Collateral flow classification level1and2accounted for84%in new onset of cerebral infarction group, level1and2accounted for only10%, and level3and4accounted for90%in no cerebral infarction group, which was higher than that of cerebral infarction, collateral blood flow grading and cerebral infarction were negatively correlated, γs=-0.76, P<0.01.4. The difference of collateral openness at level1,2and3between cerebrovascular risk factors set and don’t have cerebrovascular risk factors set was not statistically significant (P>0.05). Spearman correlation analysis showed that collateral openness at level1were positively correlated with age, hypertension, high cholesterol, diabetes and smoking, and it was negatively correlated with high homocysteine, but the difference was not statistically significant (P>0.05); collateral openness at level2were negatively correlated with a ge, hypertension, smoking, homocysteine, and it were positively correlated with high blood cholesterol and diabetes, but the difference was not statistically significant (P>0.05); collateral openness at level3were positively correlated with hypertension, high cholesterol, diabetes, smoking, and it were negatively correlated with age and homocysteine, but the difference was not statistically significant (P>0.05).5. Collateral flow grade it were negatively correlated with high blood pressure, homocysteine, smoking, and it were positively correlated with high cholesterol and diabetes, but the difference not statistically significant (P>0.05). Only the relevant between collateral flow grade and diabetes was statistically significant.Conclusion1. This study show no correlation between traditional risk factors of cerebrovascular disease and cerebral infarction, it neither shows correlation between traditional risk factors of cerebrovascular disease nether collateral openness nor cllateral blood flow classification2. MCA-M1slowly occlusing gives sufficient time for establishing collateral circulation and their flow classification of collateral circulation plays a very important role, that is the higher the rating, the less prone to occurr cerebral infarction.3. The results supports from the side the idea that when the middle cerebral artery chronic occlusion, if it is not sufficient to establish the neural network of blood vessels, perfusion resistance of arterial perfusion upstream of the neurovascular unit will increase, which will reduce the perfusion of the downstream of the neurovascular unit, making the blood does not completely and causing infarction, which may be one important mechanism of occurrence of such infarction.4. Te results of this study have shown that collateral flow grade as a collateral evaluation index is a more sensitive and effective indicator. Future research on collateral circulation should fully consider the characteristics of the dynamic changes of collateral circulation over time, and it is necessary to incorporate it into important research targets, to explore the internal mechanism of the collateral circulation formation and its compensatory role.5. The focus of stroke research in the future should be those patients with chronic arterial occlusion and have sufficient time to build collateral but with poor collateral circulation. |
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