Related Factors Study Of Acute Stroke Progression In Posterior Circulation

Objective Posterior circulation ,which is also named vertebrobasilarsystem, consists of vertebral artery,basilar artery and posterior cerebral artery.Posterior circulation infarction is a common kind of cerebral infarction and often involves the breath and circulation center and the reticular activating system.It often becomes dangerous and mortal once the stroke gets in progression.Thus the study of stroke progression in posterior circulation is payed much attention to in recent years.Stroke progression is caused by various kinds of factors.Inflammatory factors,especially matrix metalloprotein- ase(MMP)-9,attract many concerns now. MMP-9 as a hot study spot can act on extracellular matrix and destruct collagen tissue,therefore plays an important role in the rapture of atheromatous plaque and the course of brain edema.At present,most studies of stroke progression are related to anterior circulation,while studies of acute stroke progression in posterior circulation(ASPPC) are rare. The objective of this study which focused on acute stroke in posterior circulation was to sieve out risk factors for ASPPC from the clinical and biochemical data and investigate the function of plasma MMP-9 as a predictor to the infarction volume of ASPPC. Methods Ninty four inpatients(52 male cases and 42 female cases, age 64.86±8.22years,range in age from 51 to 87 years) with acute infarction in posterior circulation from September 2006 to January 2008 were enrolled in the study .All the patients were admitted in hospital from 1.5h to 12h from stroke onset and proved to be stroke in posterior circulation by MRI. According to the definition of stroke progression assessed with the Scandinavian Stroke Scale (SSS) in the European progressing stroke study(EPSS),patients met such conditions as a 2 SSS-points worsening in either conscious level, arm, leg or eye movement scores, and/or a 3 SSS-points worsening in speech score comparing the day3 assessment with the admission assessment were divided into ASPPC group,and other patients were divided into none acute stroke progression in posterior circulation(N-ASPPC) group. All the patients were examined by MRI/DWI on admission,and the patients with ASPPC were reexamined when stroke got most deteriorative;All the samples of plasma MMP-9 drawed from peripheral vein were tested by enzyme linked immunosorbent assay(ELISA),and 30 healthy persons who had medical examinations at the same time were designed as control group. All the patients were analylized as below: (1)Caculate the incidence rates of ASPPC.(2) Compare the general information (sex, age, hypertension history,diabetes mellitus history, smoke history , body temperature and mean arterial pressure on admission),swallowing function, neurological severity(SSS score)on admission and biochemical indicators (random blood glucose on admission, serum total cholesterol, serum triglyceride, plasma fibrinogen) between ASPPC and N-ASPPC group.(3)Compare MMP-9 levels of ASPPC, N-ASPPC and control group to demonstrate the MMP-9 changes in different groups. (4) Factors of significant difference between the two group and MMP-9 level(as independent variables ) were adopted to undergo Logistic regression(Forward:Wald method)analysis with ASPPC and N-ASPPC(as dependent variable) to determine the independent risk factors for ASPPC.(5)In ASPPC group, DWI volumes of infarction lesions on admission and that on the time stroke got most deteriorative were compared,and plasma MMP-9 on admission were analysed by linear correlation and regression with the DWI volumes to decide the predictor for DWI volume.All the data were analysised by SPSS13.0 software with the methods ofχ2 test ,t-test,Dunnett-T3 test,Logistic regression and linear correlation and regression.Results1 Incidence rates of ASPPC Thirty-one(32.98%) of 94 cases with acute stroke in posterior circulation were diagnosed as ASPPC. Multiple infarction lesions in posterior circulation and pons infarction had the highest incidence rates of ASPPC(46.15% and 34.48%,respectively),but no significant difference was found among different sites(P>0.05).2 Data compare between ASPPC and N-ASPPC group ASPPC group: 19 cases(61.29%) had hypertension history ; 13 cases(41.94%) had diabetes mellitus history ;19 cases(61.29%) suffered dysphagia;the SSS score 16.06±7.43;random blood glucose on admission was 8.82±2.16mmol/L. N-ASPPC group: 25 cases(39.68%) had hypertension history ;14 cases(22.22%) had diabetes mellitus history;23 cases(36.51%) suffered dysphagia;the SSS score was 21.14±6.00; random blood glucose on admission 6.05±2.20mmol/L.There was a significant difference in each factor above between ASPPC and N-ASPPC group(P<0.05).But there were no significant differences between ASPPC and N-ASPPC group in the factors of sex, age, ,smoke history , fever , mean arterial pressure, serum total cholesterol, serum triglyceride, plasma fibrinogen.(P>0.05).3 Variation of MMP-9 level in different groups ELISA tests showed that the MMP-9 level on admission of ASPPC,N-ASPPC and control group was 115.96±12.98 ng/ml, 84.47±12.63ng/ml and 53.65±8.03ng/ml respecively, and the difference between each two groups was significant(P<0.001).4 Independent risk factors for ASPPC Random blood glucose, SSS score and MMP-9 on admission entered the Logistic regression model and became independent risk factors for ASPPC.The OR value for ASPPC was 1.631,1.231 and 1.380 respectively,and the corresponding 95% confidence interval(CI) was (1.005,2.647),(1.018,1.488) and (1.146,1.662). 5 Infarction volume of ASPPC and its relationship with plasma MMP-9 level There was a significant difference between DWI volume of infarction lesion on admission and that on the time stroke got most deteriorative ( 4.57±3.22cm~3 versus 6.52±5.13 cm~3 , P<0.001). Plasma MMP-9 level on admission( as independent variable X) had a linear correlation relationship with the DWI volume either on admission or on the time stroke got most deteriorative (as dependent variable Y) ,thus it became a predictor for the infarction volume of ASPPC . The correlation coefficient was r=0.620 and r=0.713 respectively, and the corresponding regression eqation was Y=0.169X-15.087 and Y=0.282X-26.201.The correlation coefficient and regression coefficient were proved to be statistically significant (P< 0.001).Conclusions1 Hypertension history,diabetes mellitus history and high level of blood glucose at stroke onset maybe indicators for ASPPC.2 Disphagia symptom and low SSS score at stroke onset may indicate progressive cerebral infarction.3 High level of plasma MMP-9 , as a biochemical marker for the damage of atheromatous plaque and brain, is an independent risk factor for ASPPC and can predict a larger infarction volume at final.4 ASPPC may result from multi-pathomechanism.