The Clinical Study Of Relationship Between Serum Bilirubin And Ischemic Cerebrovascular Disease

Ischemic cerebrovascular disease(ICVD) is the common and frequent disease that threatens seriously the life and health of human.There is higher incidence,mortality and disability rate; moreover, there is high incidence in persons of middle and old age.It includes transient ischemic attack,cerebral thrombosis,cerebral embolism,lacunar infarction and cerebral watershed infarction.Besides,there is also a common type of ICVD—vertebro-basilar insufficiency.The pathogenesis of such diseases is obstruction of blood supply on the basis of vascular damaged or hemodynamics disturbance,leading to ischemia,hypoxia in relevant blood supply area,causing transient or persistent injury and resulting in a series of clinical symptoms and function defect.The pathogenic process and injury mechanism mainly involve in arteriosclerosis—arteriosclerosis,of which lipid abnormality is the important risk factor,is the most common etiology and mutual pathological basis in these diseases;oxidative stress is main mechanism of cell injury in arteriosclerosis,and that free radical mainly mediates the effect.Bilirubin is considered as toxic metabolic product in traditional ideas and acts as a marker of hepatic and hematic diseases in clinical practice. Actually,bilirubin is also a natural endogenous antioxidant and has the effects of inhabiting peroxidation of low density lipoprotein,anti-free radical oxidation damage and anti-inflammation in a properly higher concentration,so there is a negative correlation between bilirubin and the risk of ICVD. In the early period of disease,bilirubin and other components of heme oxygenase system are detected increasing and have cytoprotection on metabolism of the whole system.Initially,the researches on bilirubin in vasculopathy most concentrated on coronary heart disease. In 1994,Schwertner et al. first demonstrated that there was a negative correlation between serum bilirubin and coronary heart disease,in addition bilirubin was the independent risk factor of coronary heart disease.But there are fewer researches on ICVD and big differences among grouping method, concrete results and analysis on causality. For example,there are many indetermination about increasing or decreasing of bilirubin level,when to increase or decrease,which type of bilirubin increasing or decreasing,whether there is a relationship between bilirubin and sex, state of illness,prognosis,other risk factors of cerebrovascular disease. Therefore, in this study we take several aspects of controversial problems mentioned above as the breakthrough point to probe into varied level and probable effect of bilirubin in acute chronic cerebral ischemia according to detect and analysis serum bilirubin level of ICVD patients in different periods, degrees and types.We anticipate that the index can provide help for early prevention, early diagnosis and early treatment.The study collected data of 444 hospitalized patients in the first Neurology Department of China-Japan union hospital of Jilin University from January 2010 to January 2011.Firstly,we grouped them into 6 groups according to diseases—the former 3 groups were acute cerebral infarction,the fourth group was transient ischemic attack, the fifth group was vertebro-basilar insufficiency and the sixth group was control group.All the patients were with clear diagnosis and confirmed by head CT or MRI. Serum bilirubin levels were collected at the time of the next day morning after admission when they were fasting.And then we divided the group of acute cerebral infarction into the first to the third group in detail according to the period from onset of disease to blood sample collection (<48h, 48h-lw, 1w-2w).Secondly,stroke severity was assessed with Scandinavian Stroke Scale in the first group,which measures stroke severity on a 58-point scale.All the patients of the first group were examined within 24 hours of admission by investigators,then they were divided into a subgroup(severe group,<40 points) and b subgroup(mild group,≥40 points). Meanwhile, we calculated the patients'rate of pulse pressure/mean arterial pressure in the first group to evaluate atherosclerosis, furtherly we divided the first group patients into c group(mild atherosclerosis,0.306-0.429) and d group(severe atherosclerosis,0.434-0.600). Finally,data of every patient's systolic pressure and diastolic pressure before the onset of stroke were also collected.There were not significant differerces in age and sex among groups mentioned above (P>0.05),so the data were comparable.The studies indicated that serum bilirubin level declined steadily from the first group to the third group and there were significant differerces in serum total bilirubin with each other groups (P<0.05). No statistically significant differences were found from group 4 to group 6 (P>0.05). Post Hoc analysis in pairwise comparison indicated that there were significant differences between group 1 and group 2-6 (P<0.05), group 2 and group 3-6 (P<0.05),but there were no significant differences between group 3 and group 4-6 (P>0.05).The comparison results mentioned above of direct bilirubin and indirect bilirubin were equivalent to that of total bilirubin. There were no significant differences in bilirubin and rate of pulse pressure/mean arterial pressure between a subgroup and b subgroup (P>0.05),but there were significant differences in neurological deficit score (P<0.05). In addition, there were significant differences in three types of bilirubin and rate of pulse pressure/mean arterial pressure between c subgroup and d subgroup (P<0.05)In a word, the conclusions are as follows:serum bilirubin level increases significantly in acute cerebral infarction during 48 hours,as a result it can be served as a presenting index that indicates response of human body to oxidative stress. Nevertheless,it can not accurately indicate severity of oxidative stress and illness. Each type of bilirubin has no variance in development of transient ischemic attack and vertebro-basilar insufficiency.For the patients with severe atherosclerosis,the rising range of serum bilirubin is smaller and endogeneous anti-oxidative stress capability is weaker,so they may reach poor prognosis. For the patients with mild atherosclerosis, the deduction is opposite.The degree of atherosclerosis in acute cerebral infarction patients doesn't significantly correlate with primary severity of illness. We assess the severity of illness and endogeneous anti-oxidative stress capability objectively by detecting bilirubin level of ischemic cerebrovascular disease patients after admission in order to make risk evaluation and give guidance to our clinical treatment work properly.