The Effect Of Collaterals On Reperfusion Therapy In Cardioembolic Stroke Patients With Acute Large Artery Occlusion

BackgroundDecreased blood flow leads to brain damage after intracranial artery occlusion.The irreversible damaged brain tissue is called infarct core.And ischemic penumbra is functionally impaired yet still viable tissue surrounding the ischemic core.Studies have shown that collaterals affect the ischemic penumbra and infarct core volume in patients with acute ischemic stroke(AIS).Good collaterals delay the deterioration of ischemic penumbra,improve recanalization rate thereby facilitate the therapeutic effect after reperfusion therapy.Most previous studies about collaterals and stroke enrolled all stroke subtypes.However,large artery atherosclerotic(LAA)and cardioembolism(CE)have different pathophysiology mechanism,so the formation and evolution of collateral circulation in different stroke subtypes may be different.Therefore,in this study,we used TOAST classification to distinguish stroke subtypes and four-dimensional computed tomography angiography(4D-CTA)based on computed tomography perfusion(CTP)to evaluate collaterals,and aimed to clarify the following issues:1)The variant collaterals among different AIS subtypes;2)The dynamic changing pattern of collaterals in CE patients;3)The effect of collaterals on outcome after reperfusion therapy in CE patients.Part 1 The variant collaterals among different AIS subtypesAims:This study aimed to investigate the variant collaterals among different stroke subtypes,especially in CE subtype.Methods:We reviewed prospectively collected data from consecutive AIS patients with acute middle cerebral artery occlusion(MCA)/internal carotid artery(ICA)who received reperfusion therapy.The regional leptomeningeal collaterals(rLMC)score(20 points)was based on scoring extent of contrast opacification in the 6 ASPECTS cortical regions(M1-6),parasagittal anterior cerebral artery(ACA)territory,and the basal ganglia by perfusion-derived dynamic 4D-CTA.Poor collateral was defined as rLMC score 0-10,11-16 as moderate collateral and 17-20 as good collateral.Stroke subtype was determined by the TOAST classification criteria.Results:220 patients were included,42(19.1%)patients were LAA,116(52.7%)CE,41(19.1%)were stroke of undetermined etiology(UE)and no patient was stroke of other etiology.Comparing to LAA,the rLMC scores of CE patients and were lower(10 vs 14,Z=-2.536,p=0.011).CE showed a strong relationship with poor collateral,after adjustment for age,hypertension history,baseline systolic blood pressure(SBP)and diastolic blood pressure(SDP)(OR=3.318,95%CI:1.379-7.986,p=0.007).Conclusion:Stroke subtype was related to collaterals,and CE subtype was associated with worse collateral.Part 2 The relationship between onset to image time and collaterals in CE subtype Aims:This study aimed to investigate the change pattern of collaterals and the related factors collaterals in CE patients.Methods:We reviewed prospectively collected data from consecutive AIS patients with MCA/ICA occlusion who received reperfusion therapy between May 2009 and July 2017.The subtypes of LAA and UE were excluded.The rLMC score(20 points)was based on scoring extent of contrast opacification in the 6 ASPECTS cortical regions(M1-6),parasagittal ACA territory,and the basal ganglia by perfusion-derived dynamic 4D-CTA.Poor collateral was defined as rLMC score 0-10,11-16 as moderate collateral and 17-20 as good collateral.Results:This analysis included 103 patients with mean age 72 year and 49(47.6%)female.The mean onset to image time(O1T)was 176 min,and the rLMC score was 10.Comparing to moderate/good collateral,the OIT of poor collateral was longer(192 vs 158min,t=1.833,p=0.070).OIT(OR=1.006,95%CI:1.001-1.011,p=0.030)and female(OR=0.333,95%CI:0.125-0.886,p=0.028)showed a strong relationship with poor collateral,after adjustment for hypertension history,baseline SBP and SDP.Conclusion:In CE patients,OIT is related to collateral diminishment.Part 3 The effect of collaterals on outcome after reperfusion therapy among CE subtypeAims:This study aimed to investigate the relationship between collateral vessels and clinical outcome among CE subtype.Methods:We reviewed prospectively collected data from consecutive AIS patients with acute MCA/ICA who received reperfusion therapy between May 2009 and July 2017.The rLMC score(20 points)was based on scoring extent of contrast opacification in the 6 ASPECTS cortical regions(M1-6),parasagittal ACA territory,and the basal ganglia by perfusion-derived dynamic 4D-CTA.Poor collateral was defined as rLMC score 0-10,11-16 as moderate collateral and 17-20 as good collateral.3-months modified Rankin Scale(mRS)score of 0-3 was defined as good outcome.Results:This analysis included 101 patients after excluding 2 patients without 3-month follow-up data.Comparing to patients with poor collaterals,the rate of good outcome was higher(65.3%vs 32.7%,x2=10.743,p=0.001)and death rate was lower(2.0%vs 30.8%,χ2=14.874,p<0.001)in patients with moderate/good collaterals.Moderate/good collaterals showed a strong relationship with good outcome(OR=5.461,95%CI:1.521-19.602,p=0.009)and lower rate of death(OR=0.056,95%CI:0.006-0.508,p=0.010),after adjustment of age,hypertension history,baseline SBP and SDP,the National Institutes of Health Stroke Scale(NIHSS)and intra-arterial thrombectomy.Conclusion:Collaterals are related to good outcome in CE patients.Conclusion:Collaterals are related to stroke etiology,CE has worse collateral vessels.Among CE subtype,OIT is related to collateral diminishment,and robust collateral is related to better outcome and lower death rate.