Risk Factors For Hemorrhagein Patients With Cerebralarteriovenous Malformations

BackgroundCerebral arteriovenous malformations (AVM) are congenital lesions composed of a complex tangle of abnormal arteries and veins connected by one or more fistulae without an intervening capillary bed. Pathologically it is characterized by the vascular conglomerate of complex tangle.The majority of AVM are discovered after an intracerebral hemorrhage, and others are diagnosed in patients with seizures, headaches, and progressive neurological deficits. Hemorrhage from cerebral arteriovenous malformations (AVM) represents 2% of all hemorrhagic strokes. AVM are a cause of hemorrhage and disability in young adults.Objectives To analysis whether specific clinical,image and radiographic factors has relevance to the haemorrhage of cerebral arteriovenous malformations(AVM) and to predict and evaluate the risk of haemorrhage for individual AVM patients.MethodsBy the method of retrospectivey analyzing, We reviewed the clinical histories and cerebral angiograms of 139 AVM patients who admitted to Qilu hospital from June,2005 to October,2010. Possible risk factors that were investigated included age at initial diagnosis, sex, size and location of the AVM nidus, the venous drainage pattern and the numbers of venous, and the arteries feeding pattern and the numbers of arteries.And we applied Univariate and multivariate analysis with the Cox regression model to analysis independent risk factors of haemorrhage of different type of AVM and different patients.ResultsThe number of patients of AVM which suffered from haemorrhage are 95, accounting for 68% of all the patients; the nonhemorrhagic patients presenting with headaches or asymptomatic presentations are 44,accounting for 32% of all the patients. The youngest patient of the initial hemorrhage patients is 6 years old,the oldest one is 64 years old; the median haemorrhage age of all the patients is 25.00 years old; the annual bleeding rate of AVM is 2.63%. Life table method of medical statistics suggests the peak of bleeding age is 15-30-year and 40-55-year in which the bleeding risk is maximum; the bleeding survive rate shows that the patients which exceed 50% in number of people suffered from bleeding of AVM before 25 years, the age of the major bleeding patients accounting for about 38% concentrate in 10-25 years. The bleeding survive rate varies remarkablely before and after 20 years,and we can infer that this stage is the high incidence season of the AVM bleeding. Univariate and multivariate analysis with the Cox regression model suggests that independent risk factors of haemorrhage of different type of AVM and different patients, as follows that the size of the AVM nidus (P=0.007<0.05), the location of the AVM nidus (P=0.017<0.05), the numbers of venous (P=0.0150.05), and the numbers of the feeding arteries (P=0.0430.05), which all have statistical significance. And the location of the AVM nidus (B=0.375>0) has positive correlation with the bleeding risk(hemisphere>deep part>cerebellum); the size of the AVM nidus (B=-0.510<0) has negative correlation with the bleeding risk, that smaller size of lesion and more risk; the number of the feeding arteries (B=0.483>0) has positive correlation with the bleeding risk,that less arteries and more risk; the number of the venous (B=-0.741<0) has negative correlation with the bleeding risk, that more venous and more risk.Conclusions 1. The most bleeding incidents of the AVM occur in the young people, exceeding 50%in number of people suffered from bleeding of AVM before 25 years. the bleeding of AVM has two peak of risk which are 20-25 years and 45-55 years. The bleeding of AVM in young people has something with the chang of hormone level and it may be relevant with cerebral blood vessels disease induced by hypertention and atherosclerosis.2. The size of the AVM nidus, the location of the AVM nidus, the numbers of venous, and the numbers of the feeding arteries are the independent risk factors of haemorrhage of different type of AVM and different patients. And the AVM nidus of cerebellum and deep part have higher bleeding risk than these of hemisphere; the smaller AVM nidu occur the bleeding incidents than the larger ones; and more feeding arteries of AVM has higher bleeding risk; the lesions with single venous occur bleeding more easily than these with more venous.To these AVM patients of no bleeding history, we advice that they should take DSA examination of cerebral blood vessles by which we can not only diagnose the lesion correctly, but also acknowledge the size,location,and the feeding arteries and drainage venous number of the lesion. And we can evaluate independent risk of haemorrhage and predict of different type of AVM and different patients combining with clinical characteristics, and on this base we can chose the best therapy program in order to decrease the harm to the patients.