The Outcome Of Endovascular Treatment For Intracranial Atherosclerotic Stenosis&the Analysis And Management For Associated Factors With The Outcome

Part I The long-term outcome of endovascular treatment versus medical treatment for severe intracranial artery stenosis of anterior circulationBackground and Objective:Intracranial atherosclerotic disease is one of the most common causes for ischemic stroke in Asian populations. Patients with severe intracranial stenosis carried a high risk of subsequent stroke. Therefore, patients with severe intracranial stenosis maybe obtain benefits from endovascular treatment. However, the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke and Intracranial Stenosis (SAMMPRIS) trial showed that aggressive medical treatment was better than intracranial stent. The trial was prematurely terminated due to high rate of the periprocedural complication in endovascular arm. The results were limited to1year of follow up, and we are yet to see longer-term outcome data to evaluate whether endovascular treatment provides benefits for preventing stroke. In this part, we aimed to compare long-term outcome of endovascular treatment with medical treatment in severe intracranial atherosclerotic stenosis of anterior circulation based on data from Nanjing Stroke Registry Projects.Methods:Retrospective analysis of consecutive patients who had transient ischemic attack or ischemic stroke attributed to severe intracranial atherosclerotic stenosis of anterior circulation between June2006and November2011in Nanjing Stroke Registry Projects was conducted. Patients were either treated with endovascular therapy (endovascular treatment group) or with medicine (medical treatment group). The primary endpoint was any stroke or death within30days after enrollment and ischemic event in the territory of qualifying artery beyond30days after a revascularization procedure for qualifying lesion. The secondary endpoint was stroke in territory of qualifying artery beyond30days. The deadline to follow up was the first of May2012in this study. The Kaplan-Meier method was performed to compare the cumulative events rate between two groups. Multivariate Cox regression analysis was employed to identify the independent risk factors for secondary endpoint.Results:Of the142patients enrolled,69patients were in endovascular treatment group and73patients in medical treatment group. The cumulative events rate of the primary endpoints over time in30-day,1-year,2-year,3-year in endovascular treatment group and in medical treatment group were13%,15%,21%,29%and1%,15%,22%,27%, respectively. The occurrence of primary endpoint was not statistically different between two groups (P=0.805). But for secondary endpoint, endovascular treatment was superior to medical treatment (P=0.026), the occurrence of the secondary endpoint in endovascular treatment group and in medical group at1-year,2-year,3-year were5%,13%,15%and14%,21%,34%respectively. Multivariate Cox analysis revealed that treatment modality (medical treatment group versus endovascular treatment group, HR=2.601,95%CI1.042-6.495, P=0.041) and the number of major vascular risk factors (≥2versus0～1, HR=3.322,95%CI1.116～9.894, P=0.031) were independent risk factors for stroke in territory of qualifying artery beyond30days.Conclusion:The long-term results from endovascular treatment for anterior circulation severe intracranial atherosclerotic stenosis were not superior to medical treatment. But the efficacy of endovascular treatment for preventing stroke in territory of qualifying artery beyond30days was better than medical treatment. Our study demonstrated that the high rate of periprocedural complication offset the benefits from preventing subsequent stroke by endovascular treatment for intracranial stenosis disease. Part II Learning curve for intracranial angioplasty and stenting in single centerBackground and objective:Our study demonstrated that the high rate of periprocedural complication offset the benefits from preventing subsequent stroke by endovascular treatment for intracranial stenosis disease. If the rate of complication could decrease to an acceptable level, intracranial angioplasty and stenting (IAS) was still a promising therapy for intracranial stenosis disease. The periprocedural complications would decrease with increasing surgical procedures experience. To date, there are no data available for determining the essential caseload need to acquire sufficient amount of experience for performing IAS. We aimed to1) assess whether the operator experience affects outcome of IAS and2) to identify the specific caseload need to overcome the learning-curve effect based on data from consecutive patients treated with IAS in Nanjing Stroke Registry Projects.Methods:Retrospective analysis of periprocedural complications of consecutive patients who underwent intracranial angioplasty and stenting between March2004and May2012in Nanjing Stroke Registry Projects was conducted. The outcome variables used to assess the learning curve were periprocedural complications (including transient ischemic attack, ischemic stroke, vessel rupture, cerebral hyperperfusion syndrome, and vessel perforation). The operative experience was defined as each individual operator’s case sequence number, the operative sequence number was divided into3levels of1-20cases,21-40cases,>40cases. Multivariable logistic regression analysis was employed to illustrate the existence of learning-curve effect in IAS. A risk-adjusted cumulative sum chart was performed to identify the specific caseload to overcome learning-curve effect and perform IAS with an acceptable level of complications.Results:A total of188patients with194lesions were treated with intracranial angioplasty and stenting by four operators in our center. The number of procedures performed by each of the four operators was70,64,31and29, respectively. The overall rate of30-days periprocedural complications was12.4%(24/194). After adjusting for case-mix, multivariate logistic regression analysis showed that operator experience (1-20cases versus>40cases, OR=4.436,95%CI1.214-16.206, P=0.024) was an independent predictor for periprocedural complications. The learning curve of IAS to overcome complications in a risk-adjusted cumulative sum chart was21cases. When beyond the inexperienced phase, the rate of complications was5.5%(6/110). Conclusion:Operator’s level of experience significantly affected the outcome of IAS. Moreover, we observed that the amount of experience sufficient for performing IAS in our center was21cases. All four operators have passed learning phase, the rate of complication of IAS decreased to an acceptable level. PartⅢ Interim analysis of Atorvastatin for preventing occlusion and restenosis after intracranial artery stentingBackground and objective:It is an acceptable option for patients who had recurrent ischemic symptoms despite medical therapy were treated with intracranial stent in our center. According to recent review, the overall1-year restenosis rate of intracranial stenting was about25%. Of these about33%restenosis was symptomatic. Compared with relatively good durability of angioplasty and stenting procedures within the carotid artery, the high incidence of restenosis in intracranial stenting appears to be another important concern. Unlike the recoil of vessel was primary reason for restenosis in primary angioplasty, the neointimal proliferation after stent implantation served as a major responsibility of restenosis. Preventing restenosis after stent implantation was an effective measure for maintaining durability of intracranial stenting. Previous studies demonstrated that high dose statin could inhibit inflammatory response, consequently reduced the restenosis after coronary stenting. However, it is unclear that whether high dose statin with similar effective for preventing restenosis and in-stent occlusion after intracranial stenting. We conduct a prospective, randomized, controlled, single-center, pilot clinical trial to compare the efficacy different doses of statin for preventing restenosis and occlusion after intracranial stenting.Methods:Patients who had recurrent ischemic symptom despite medical therapy were randomly assigned to high dose atorvastatin (40mg/day for the first year, and change to20mg/day from the second year) or regular dose atorvastatin (20mg/day) by means of block randomization method (4numbers as a block). Intracranial artery stenosis leading to ischemic symptom was detected by conventional cerebral angiography, which involving arteries including intracranial internal carotid artery, middle cerebral artery Ml segment, vertebral artery V4segment and basilar artery. The primary observed outcome was In-Stent Restenosis and occlusion detected by conventional cerebral angiography or CTA on6-months or9-months follow up or any time if a symptomatic event occurred after stenting implantation. In-Stent Restenosis was defined as diameter stenosis>50%at previously treated lesion and adjacent segment, or compared to baseline the diameter stenosis increase by at least20%if previously treated lesions with residual stenosis>30%. The clinical endpoint was any cerebrovascular events or death within30days after enrollment and any ischemic cerebrovascular events in territory of qualifying artery and revascularization of the target lesion beyond30days after enrollment. The Kaplan-Meier method was employed to compare the clinical endpoint between two treatments.Results:A total of59patients were enrolled from December2010to September2012, of29patients were assigned to high dose atorvastatin group and30patients to regular dose group. The median follow up time, which was ongoing, was13months. The overall rate of30-days periprocedural complication was.1.7%(1/59). To date, there were41patients had follow up data of conventional cerebral angiography or CTA. Of21patients were in high dose group and20patients in regular dose group, respectively. The in-restenosis and occlusion rate of high dose group (33.3%,7/21) was slightly higher than regular dose group (30.0%,6/20), but there was no statistical significant different between two groups (P=0.819). The1-year cumulative events rate of clinical endpoint in high dose group were11%compared with that of10%in regular dose group, there was not statistically significant different (P=0.593).Conclusion:This study showed that intracranial stenting is a safe choice for patients who had recurrent ischemic symptom due to intracranial stenosis in our center. But based on the current data the high dose atorvastatin was not superior to regular dose atorvastatin for preventing occlusion and restenosis after intracranial stent implantation. Although intracranial stenting was safe, further studies into preventing in-stent restenosis and occlusion after stent placement are warrant.