| BackgroundCerebral watershed infarction(CWI)is a special type of cerebral infarction,which is located in major cerebral arteries border zones.In clinical practice,according to hemodynamic causes and image characteristics,we classify cerebral watershed infarction as follows:external watershed infarction(EWI)?internal watershed infarction(IWI)and mixed watershed infarction(MWI).Currently it is considered that hypoperfusion and microembolization are the main mechanisms for the occurrence of CWI in intracranial cerebral arteries border zones.Previous studies reported that CWI accounted for around 10%of all kinds of cerebral infarctions.We can draw the conclusion from our clinical practice that the present occurrence of CWI exceeds this proportion.A majority of cerebral watershed infarctions are accompanied by the stenosis or occlusion of the ipsilateral artery.Some cerebral watershed infarctions with ipsilateral artery lesions have the tendency to get aggravated and progressive.The effect of conservative standard medication treatment is not satisfying.In recent years the emerging neuro-intervention method--endovascular stent angioplasty,provides these patients with a new weapon.This treatment effectively improves the clinical prognosis of some patients.However,so far there have been few studies on the selection of patients and the timing of intervention treatment.Most clinical doctors are groping their ways forward based on their own experiences.This study has three parts,aiming to provide some clinical evidences.Firstly we discussed the present situation of CWI through clinical registered study.Meanwhile we discussed the clinical characteristics and vascular features.By retrospectively studying the cases of cerebral watershed infarction patients with ipsilateral carotid artery stenosis in our medical center,we analyzed the safety and effectiveness of early carotid artery stenting(CAS)for patients,aiming to study the clinical efficacy of this surgery performed in an early stage.The last part is clinical registered study.By comparing cerebral watershed infarction patients who received CAS in an early stage and those who received the delayed CAS,we analyzed the occurrence of perioperative complications,?the clinical prognosis of patients and ultimately analyzed the ideal timing for the surgery.Part OneClinical and vascular characteristics of cerebral watershed infarctionObjective:To discuss the occurrence rate of cerebral watershed infarction.To discuss the unique clinical and vascular characteristics of cerebral watershed infarction compared to other types of cerebral infarctions.To discuss the clinical and vascular characteristics of different types of cerebral watershed infarctions.Methods:Between September 2015 and March 2016,we sequentially recruited patients who had new cerebral infarctions diagnosed by brain MRI.We classified the recruited new cerebral infarctions into 8 subtypes.These 8 subtypes were:external watershed infarction(EWI)?internal watershed infarction(IWI)?mixed watershed infarction(MWI)?middle cerebral artery territory infarction?anterior cerebral artery territory infarction?anterior choroidal cerebral artery territory infarction?posterior cerebral artery territory infarction?brain stem and cerebellum infarction.We used carotid artery ultrasound and brain Magnetic Resonance Angiography(MRA),Computed Tomography Angiography(CTA)if necessary,or even Digital Subtraction Angiography(DSA)to examine and recorded the conditions of arteries.In the meantime we recorded clinical characteristics of cerebral infarction patients.We compared the basic conditions?risk factors of cerebral vascular disease?clinical characteristics?vascular features of the CWI group and non-CWI group.The count data was compared using chi-square statistics.The measurement data was compared using t test.We used the same method to compare the basic conditions?risk factors of cerebral vascular disease?clinical characteristics?vascular features in the two subtypes of CWI,the EWI and IWI.The level of significance was taken at p<0.05.Results:Ultimately we recruited 852 cases of patients in the study who suffered new cerebral infarctions diagnosed by MRI.Among them there were 540(63.38%)cases ofanterior circulation cerebral infarction,312(36.62%)cases of posterior circulation cerebral infarction,222(26.06%)cases of cerebral watershed infarction,297(34.86%)cases of middle cerebral artery territory infarction,15(1.76%)cases of anterior cerebral artery territory infarction,6(0.70%)cases of anterior choroidal cerebral artery territory infarction,65(7.62%)cases of posterior cerebral artery territory infarction,230(27.00%)cases of brain stem and cerebellum cerebral infarction,17(2.00%)cases of mixed posterior circulation cerebral infarction.The baseline conditions of patients in CWI group and non-CWI group were approximately the same.For patients in CWI group,the occurrence of TIAs before stroke onset was evidently more frequent than that in non-CWI group.In CWI group the proportion of patients who had symptomatic epilepsy after the stroke was evidently larger than that in non-CWI group.In respect of early progression.there was no difference between the two groups.In CWI group the proportion of patients who had ipsilateral carotid artery stenosis or occlusion was evidently larger than that in non-CWI group.Besides,in CWI group the proportion of patients who received interventional therapy was evidently larger than that in non-CWI group.Altogether there were 222 case of patients who had CWI and were recruited.Among them therewere 95(42.8%)cases of EWI,103(46.4%)cases of IWI,24(10.8%)cases of MWI.In the subtypes of CWI,the baseline conditions of patients in EWI group and IWI groups were approximately the same.The proportion of patients who had early progression in IWI group was evidently larger than that in the EWI group,with the P=0.032,and the difference was statistically significant.In EWI group the proportion of patients who had symptomatic epilepsy was larger than that in the IWI group and the difference was statistically significant.In IWI group the proportion of patients who had ipsilateral carotid artery stenosis or occlusion was evidently larger than that in EWI group.Conclusions:1?Cerebral watershed infarction is an important subtype of cerebral infarction and its occurrence rate is higher than before.2?Compared with non-CWI patients,CWI patients have unique clinical characteristics.CWI patients have more tendency to experience TIAs and symptomatic epilepsy in the early stage of the stroke.Compared with non-CWI patients,CWI patients have unique vascular features.CWI patients have more conditions of ipsilateral carotid artery stenosis or occlusion.Besides,there are larger proportion of them who need interventional revascularization.3?EWI and IWI are the main subtypes of CWI.Compared with IWI patients,EWI patients have different clinical characteristics.EWI patients have more tendency to experience seizure in the early stage.Whereas IWI patients have worse neurological functions than EWI patients.The mechanisms of the two types of cerebral infarctions are not exactly the same.Compared to EWI,larger proportion of IWI patients have ipsilateral carotid artery stenosis or occlusion,and early progression is more common.Part TwoStudy on the safety of early carotid artery stenting for patients with cerebral watershed infarction due to the stenosis of ipsilateral carotid arteryObjective:To evaluate the safety of early carotid artery stenting(CAS)for patients with cerebral watershed infarction(CWI)due to the stenosis of ipsilateral carotid artery.Meanwhile,we also wanted to study,compared with standard medication treatment,whether early CAS for CWI patients could improve the recovery of neurological function and decrease the occurrence rate of second stroke.Methods:We retrospectively studied 120 cases of CAS for CWI patients due to severe stenosis of ipsilateral carotid artery between March 2011 and April 2014.We divided these patients into two groups.The inclusion criteria for patients in group 1:patients who received CAS within one week after CWI onset.The inclusion criteria for patients in group 2:patients who didn't receive CAS treatment within one month after the admission and just received combined treatment of 1 OOmg/day aspirin and 75 mg/day clopidogrel.The National Institutes of Health Stroke Scale(NIHSS)scoresand modified Ranking Scale(mRS)scores of all patients were recorded after the admission.In group 1,when patients suffered from descent of heart rate or blood pressure,we used atropine to raise the heart rate and dopamine to raise the blood pressure.After endovascular treatment,the blood pressure of all the patients was monitored for 48 hours.Systolic pressure was controlled in the level of about 80-90%,of pre-endovascular treatment.Second strokes within one month and periprocedural complications were recorded.NIHSS scores as well as mRS scores of patients in the two groups were also recorded.The mean of NIHSS scores in the 2 groups were compared by independent sample t tests.The pre-treatment and post-treatment NIHSS scores were also compared by independent sample t tests.The occurrence rate of second stroke and the mRS scores in the two groups were compared using chi-square statistics.The difference value of pre-treatment and post-treatment in two groups were also compared by statistics of independent sample t test.The level of significance was taken at p<0.05.Results:A total of 63 patients received early CAS within 1 week(averagely 4.9 days from the symptom onset).Before the treatment the mean of NIHSS score was 8.52 ?2.46.Before the treatment the proportion of patients with mRS score<2 was 38%(24 of 63).The completion rate of the treatment was 100%.3 patients(4.8%,3 of 63)had periprocedural complications.After 30 days the mean of NIHSS score was 3.03 ?1.44.After 30 days the proportion of patients with mRS score ? 2 was 75%(47 of 63).Altogether we collected the data of 57 cerebral watershed infarction patients due to the stenosis of ipsilateral carotid artery who received standard medication treatment.In group 2,the mean of NIHSS score was 7.84 ±2.64 before the treatment.The number of patients with mRS score ? 2 was 17(17 of 57,29%).7 patients(7 of 57,14%,)suffered a second stroke.The mean of NIHSS score was 3.84 ± 1.73 after 1 month.After 30 days,the number of patients with mRS score,2 was 31(31 of 57,54%).Before the treatment,the means of NIHSS scores and the numbers of patients with mRS score ? 2 in group 1 and group 2 had no significant differences(p = 0.34).After 1 month the difference of the means of NIHSS scores in group 1 and group 2 was statistically significant(p = 0.006).Post-treatment NIHSS scores in group 1 were evidently lower than that in group 2.The reduction value of NIHSS scores of pre-treatment and post-treatment in the two groups were-5.49 ±2.12 and-4.00 ± 1.98 respectively,and the difference was statistically significant(p<0.05).After the treatment,patients in group 1 had larger reduction of NIHSS score than patients in group 2.In group 1 and group 2,the occurrence rates of second stroke were not significantly different(p= 0.123).After the treatment,the proportions of patients with mRS score ? 2 in group 1 and group 2 were statistically different(p =0.02).The treatment effect in group I was better.Conclusions:1?Early CAS for patients with CWI due to the stenosis of ipsilateral carotid artery is safe,without increasing the periprocedural complications.2?For CWI patients with stenosis of ipsilateral carotid artery,early CAS can improve the NIHSS score after 30 days,and the treatment effect is better than standard medication treatment group.3?For CWI patients with stenosis of ipsilateral carotid artery,early CAS can raise the probability of good clinical outcome(mRS score ?2),the effect of which is better than standard medication treatment group.4?This study cannot answer the question:for CWI patients with stenosis of ipsilateral carotid artery,whether early CAS can decrease the occurrence rate of second stroke.Part ThreeStudy on the optimal time window of interventional treatment for patients with cerebral watershed infarction due to the stenosis of ipsilateral carotid arteryObjective:In this study we divided clinical registered CWI patients due to the stenosis of ipsilateral carotid artery who received CAS treatment into 2 groups:CAS within 2 weeks group and CAS after 2 weeks group.By comparing the safety and clinical prognosis of the two groups,we tried to find the optimal time window of interventional treatment for these patients.Methods:Between July 2014 and December 2016,we sequentially recruited new CWI patients with ipsilateral internal carotid artery extracranial stenosis.Basic conditions of the two groups were recorded,including age,sex.Risk factors:hypertension?diabetes mellitus type 2?coronary artery atherosclerotic heart disease?smoking?alcohol consumption were also recorded.After admission the NIHSSscoring of all patients was completed.If the symptoms of patients aggravated during hospitalization,the pre-treatment NIHSS scores were taken after the aggravation.Patients whose TICI(thrombolysis in cerebral infarction)score was 3 points or more directly received the CAS procedure.For patients whose TICI score was less than 3 points,we took the stenting by stages therapy.All patients took the first check-up after 30 days.After 90 days they underwent second check-up,during which they were scored using NIHSS and mRS.Meanwhile they took B ultrasonography of the carotid arteries in order to check the shape of the stents.The measurement data of the two groups were recorded in mean ± SD and were compared through t test.The count data of the two groups were recorded in number and percentage and were compared using chi-square statistics.The level of significance was taken at p<0.05.Results:Ultimately there were 112 patients who were recruited in the study.Among them 61 patients received CAS treatment within two weeks from the symptom onset.51 patients received CAS treatment 2 weeks after the stroke.The average ages of patients in CAS within 2 weeks group and CAS after 2 weeks group were 63.11 ±4.86 and 63.96±4.47 respectively.Before the treatment,the NIHSS score of patients in CAS within 2 weeks group was 8.69±2.34,whereas in CAS after 2 weeks group it was 8.47±2.76.For CAS within 2 weeks group,the average extent of carotid artery stenosis was 84.01 ±10.13,while for CAS after 2 weeks group,the average extent was 85.27 ±9.77.In respect of patients' ages,sexes,risk factors,NIHSS scores before the intervention,average extent of carotid artery stenosis,there were no statistical differences between the two groups.Altogether there were 112 patients who successfully went through carotid artery stenting surgery.The success rate of the surgery was 100%.The average period of time from symptom onset to the surgery for patients in CAS within two weeks group was 6.11±2.0 days,whereas for patients in CAS after two weeks group,it was 17± 2.17 days.In perioperative period,42 patients(68.9%)in CAS within two weeks group experienced heart rate or blood pressure descent,while the number of patients had the similar experiences in CAS after two weeks group was 34(66.7%),which had no statistical difference.In CAS within two weeks group,there were 3 patients who had periprocedural complications,while in CAS after two weeks group,2 patients had periprocedural complications.There was no statistical difference between the two groups.The numbers of patients suffered cerebral hemorrhage or hyperperfusion syndrome in the two groups is 1(1.6%)and 1(2.0%)respectively.There was no statistical difference.No patient in the two groups experienced periprocedural acute coronary artery event or death.After 90 days the NIHSS scores of patients in CAS within two weeks group and CAS after two weeks group were 3.13±1.85 and 4.29± 1.84 respectively,which had statistical difference.The improvement of NIHSS scores before the surgery and 90 days after the surgery of the two groups were 5.56 ±2.11 and 4.18 ± 1.80 respectively,which had statistical difference.Good clinical results(mRS ? 2)of patients in the two groups were 39(63.9%)and 23(45.1%)respectively,which had statistical difference.The numbers of patients who had ipsilateral cerebral infarction?the proportion of restenosis inside stents?the proportion of symptomatic restenosis of the two groups had no statistical difference.Conclusions:1?For CWI patients due to the stenosis of ipsilateral carotid artery,receiving CAS within two weeks is as safe as receiving CAS after two weeks.without increasing the probability of complications.2?For CWI patients due to the stenosis of ipsilateral carotid artery,compared with receiving CAS after two weeks,receiving CAS within two weeks can effectively decrease NIHSS scores,and improve the probability of good clinical results(mRS?2).3?For cerebral watershed infarction patients due to the stenosis of ipsilateral carotid artery,compared with receiving CAS after two weeks,receiving CAS within two weeks has the same efficacy in respect of preventing recurrence of new stroke.4?For CWI patients due to the stenosis ofipsilateral carotid artery,if the NIHSS score?15,the optimal time window of interventional treatment is CAS within two weeks. |
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