Compensatory mechanisms for chronic cerebral hypoperfusion in patients with carotid occlusion

BACKGROUND AND PURPOSE: The purpose of this experiment was to assess long-term cerebral hemodynamic and metabolic changes in patients with increased oxygen extraction fraction (OEF) in the hemisphere distal to an occluded carotid artery who remain free of stroke. Methods--Ten patients with increased OEF and no interval stroke underwent repeated positron emission tomography examinations 12 to 59 months after the initial examination. Quantitative regional measurements of cerebral blood flow, cerebral blood volume, cerebral rate of oxygen metabolism (CMRO2), and OEF were obtained. Regional measurements of the cerebral rate of glucose metabolism (CMRGlc) were made on follow-up in 5 patients. Statistical significance (P<0.05) was measured with t tests and linear regression analysis. RESULTS: The ipsilateral/contralateral OEF ratio declined from a mean of 1.16 to 1.08 (P=0.022). Greater reductions were seen with longer duration of follow-up (P=0.023, r=0.707). The cerebral blood flow ratio improved from 0.81 to 0.85 (P=0.021). No change in cerebral blood volume or CMRO2 was observed. CMRGlc was reduced in the ipsilateral hemisphere (P=0.001 compared with normal), but the CMRO2/CMRGlc ratio was normal. CONCLUSIONS: Increased OEF improves in patients with carotid occlusion and no interval stroke. This improvement in OEF is due to an improvement in collateral blood flow.     

Prognosis of asymptomatic carotid occlusion

Ninety-four asymptomatic patients with internal carotid artery occlusion were followed for a mean of 44 months, 16% suffered strokes and 11.7% reported transient ischemic attacks (TIA). The annual stroke and TIA rates were 4.4% and 3.2%, respectively, the annual mortality was 11.3%. In 27 asymptomatic patients progression of extracranial arterial disease to occlusion was observed: 7.4% of these patients suffered from stroke and 18.5% reported TIA's during that period. Thus the annual stroke rate was lower (1.9%) but the TIA rate higher (4.7%) than post-occlusive rates. These data reflect an increase risk in patients with progressive high-degree carotid stenosis which continues after occlusion. This may favour carotid endarterectomy for selected patients in the pre-occlusive state because medical treatment has not been shown to prevent progression of stenosis to occlusion.     

Cerebral cortical microinfarcts in patients with internal carotid artery occlusion

Cerebral cortical microinfarcts (CMI) are small ischemic lesions that are associated with cognitive impairment and probably have multiple etiologies. Cerebral hypoperfusion has been proposed as a causal factor. We studied CMI in patients with internal carotid artery (ICA) occlusion, as a model for cerebral hemodynamic compromise. We included 95 patients with a complete ICA occlusion (age 66.2 ± 8.3, 22% female) and 125 reference participants (age 65.5 ± 7.4, 47% female). Participants underwent clinical, neuropsychological, and 3 T brain MRI assessment. CMI were more common in patients with an ICA occlusion (54%, median 2, range 1–33) than in the reference group (6%, median 0; range 1–7; OR 14.3; 95% CI 6.2–33.1; p<.001). CMI were more common ipsilateral to the occlusion than in the contralateral hemisphere (median 2 and 0 respectively; p<.001). In patients with CMI compared to patients without CMI, the number of additional occluded or stenosed cervical arteries was higher (p=.038), and cerebral blood flow was lower (B −6.2 ml/min/100 ml; 95% CI −12.0:–0.41; p=.036). In conclusion, CMI are common in patients with an ICA occlusion, particularly in the hemisphere of the occluded ICA. CMI burden was related to the severity of cervical arterial compromise, supporting a role of hemodynamics in CMI etiology.     

Cognitive and physical performance in patients with asymptomatic carotid artery disease

The purpose of this study was to determine if patients with asymptomatic carotid artery stenosis and occlusion demonstrate deficits in cognitive and physical performance. The relationship between cognitive measures and performance of instrumental activities of daily living was examined. Seventy-nine patients with asymptomatic carotid artery stenosis of moderate and severe degrees or occlusion were tested. Cognition was assessed via the repeatable battery for the assessment of neuropsychological status (RBANS) and the executive interview (EXIT). Physical performance was assessed via the physical performance test (PPT) and the Lawton instrumental activities of daily living (IADL). Deficits in the RBANS visuospatial/constructional, attention, language and delayed memory domains were found for patients with occlusion. Deficits in all RBANS domains were found for the moderate stenosis subgroup, and deficits in all domains except language were found in the severe subgroup. No deficit was found in executive function in any group. Additionally, deficits were related to sidedness of involvement with visuospatial/constructional deficits related to right sided disease, and deficits in all cognitive domains except language were found in left sided and bilateral disease. Decreased performance on the PPT was identified in all three subgroups with the lowest scores in the moderate stenosis subgroup and the highest scores in the severe stenosis subgroup. The Lawton IADL did not identify any decrease in performance. Deficits in cognitive and physical function were found in this observational study of patients with asymptomatic carotid artery stenosis and occlusion, indicating that asymptomatic patients may not be truly asymptomatic. These areas of function and the potential change in their status need to be considered when patients are being evaluated for interventions to manage their carotid artery disease.     

无症状性ICA患者行颈动脉支架置入术对认知功能的影响

目的 探讨颈动脉支架置入术对无症状性颈动脉高度狭窄患者认知功能的影响。方法 以本院2012年2月～2014年2月治疗的96例行颈动脉支架置入术的无症状性颈动脉高度狭窄患者为研究组,以同期90例行常规内科治疗的无症状性颈动脉高度狭窄患者为对照组,分别在治疗前3 d和治疗后3个月采用连线测验(TMTa、TMTb)、简易智能量表(MMSE)、阿尔茨海默病评估量表认知部分(ADAS-Cog)评估患者的认知功能。结果 研究组患者治疗前3 d颈动脉狭窄为(79.51±6.02)%,治疗后3个月残余狭窄为(13.52±6.01)%,治疗后3个月狭窄程度较治疗前3 d有明显改善(P<0.05); 治疗后研究组狭窄程度显著低于对照组(P<0.05)。与治疗前3 d相比,研究组治疗后3个月患者的MMSE评分明显增加(P<0.05),TMTa、TMTb和ADAS-Cog评分均明显降低(P<0.05); 治疗3个月研究组各指标均显著优于对照组(P<0.05)。结论 颈动脉高度狭窄可能造成患者认知功能损伤,即使是无症状的此类患者,行颈动脉支架置入术对患者的认知功能也具有一定的改善作用,并且可降低颈动脉狭窄程度。     

Outcome in patients with stroke associated with internal carotid artery occlusion

BACKGROUND: The clinical outcome in patients with stroke associated with internal carotid artery (ICA) occlusion is poor, although a minority may recover without dependency. The purposes of this study were (1) to assess the predictive factors of adverse outcome in patients with stroke associated with an occlusion of the ICA and (2) to evaluate the rate of spontaneous recanalization of an occluded ICA. METHODS: A total of 177 consecutive patients with first-ever ischemic stroke associated with ICA occlusion were prospectively examined from the Perugia Stroke Registry. Mean age was 71.4 +/- 14.3 years; 53% were males. Multiple regression models were used to analyze predictors of mortality, dependency and ipsilateral stroke recurrence. RESULTS: The most probable cause of occlusion was atherosclerosis in 65%, cardioembolism in 22%, dissection in 9% and other causes in 4%. Thirty percent of the patients died within 30 days. After a mean follow-up of 420 days (range 1-1,970 days), 45% of the patients had died and 75% had died or were disabled. Another 6% of the patients had a recurrent stroke ipsilateral to the occluded carotid artery. Age was the only predictor of 30-day mortality (77.7 +/- 9.7 vs. 68.7 +/- 15.2 years; p = 0.03) and of long-term mortality or disability (p < 0.003). Hypertension (OR 0.42; 95% CI 0.17-1.00; p = 0.05) was associated with a better outcome within 30 days from stroke onset. Previous ipsilateral transient ischemic attack (OR 0.24; 95% CI 0.06-0.89; p = 0.03) and hyperlipidemia (OR 0.38; 95% CI 0.15-0.99; p = 0.049) were predictors of a better outcome with respect to long-term mortality or disability. No predictors of ipsilateral stroke recurrence were found. One hundred and five out of 177 patients had adequate follow-up ultrasound data. After a mean follow-up of 1.8 years, 10 patients had recanalization of the occluded ICA (2/71 atherosclerosis, 3/19 cardioembolism and 5/15 dissection). CONCLUSIONS: After a mean follow-up of 1.2 years, 45% of the patients with stroke associated with ICA occlusion had died, while 75% had died or were functionally dependent. The presence of either previous ipsilateral transient ischemic attack, hypertension or hyperlipidemia was associated with a favorable outcome. Recanalization of an occluded ICA occurred in a minority of patients and it was associated with cardioembolism and with arterial dissection.     

Patterns of cerebral perfusion in patients with asymptomatic internal carotid artery disease

BACKGROUND: The perfusion profile of patients with asymptomatic internal carotid artery (ICA) disease has not been well studied. The purpose of this study is to describe the perfusion patterns of patients with asymptomatic ICA disease using computed tomography perfusion (CTP) and its potential value in identifying patients at higher risk for transient ischemic attacks (TIAs) or strokes. METHODS: We analyzed 32 patients with asymptomatic high grade ICA disease who had CTP and computed tomography angiography (CTA) of the head and neck. Twenty-four patients had severe ICA stenosis and eight had ICA occlusion. The degree of ipsilateral external carotid artery (ECA) and contralateral ICA stenosis, patency of the anterior communicating artery (ACOM), A1 segment and posterior communicating artery (PCOM) were evaluated in all patients. RESULTS: Sixteen patients had normal CTP and the other 16 patients had cerebral hypoperfusion, characterized by abnormalities in one or more of the three perfusion maps. Ipsilateral hypoplastic A1 segment was more frequent in the group with cerebral hypoperfusion (p = 0.025). Ipsilateral TIAs occurred in two patients, both with cerebral hypoperfusion. CONCLUSION: Cerebral hypoperfusion is present in half of the patients with asymptomatic ICA disease, predominantly in patients with a hypoplastic ipsilateral A1 segment. These patients likely represent a higher-risk group for symptomatic brain ischemia.     

External carotid artery stenting in symptomatic internal carotid artery occlusion

We report the case of a patient with an anterior ischemic stroke due to tandem occlusion of the left M2 segment and ipsilateral internal carotid artery (ICA), with concomitant severe stenosis of the ipsilateral external carotid artery (ECA) and contralateral ICA, and moderate stenosis of the left vertebral artery (VA); as thrombectomy was not possible, stenting of the right ICA was performed. Two days after significant recovery, the patient showed neurological deterioration when in upright position, and brain magnetic resonance imaging confirmed decreased cerebral blood flow on the left hemisphere. Stenting of the left ECA and balloon angioplasty of the ipsilateral VA were performed in order to increase collateral flow, with an almost complete resolution of symptoms. This case highlights the importance of assessing the collateralization pattern when an ICA occlusion is present, and the potential need to revascularize an ipsilateral stenotic ECA.     

Spontaneous history of asymptomatic internal carotid occlusion

Forty-nine patients with ICA occlusion, who presented without any neurological signs or symptoms, were prospectively followed for an average of 31.2 months. Eight patients (16%) suffered a stroke during follow-up, of which five were within the vascular territory of the occluded artery--5 patients (10%) developed TIAs 4 of which were ipsilateral to the occluded artery. Non-invasive vascular follow-up did not reveal a progression of extracranial arterial disease in the majority of later symptomatic patients. Twenty-three patients (46.9%) died during follow-up, coexisting coronary artery disease being the major cause of death.     

颈总动脉闭塞患者的临床特点分析

目的分析颈总动脉患者临床特点,以加深对该病变的认识。方法对14例颈总动脉患者的临床资料、影像及超声进行分析。结果14例颈总动脉闭塞患者中,表现为病变对侧的肢体无力7例（50%）,病变同侧一过性黑朦发作5例（35.7％）,晕厥发作5例（35.7％）;MRI显示新发梗死7例;TCD显示眼动脉血流正常6例,眼动脉侧支开放（颈内外侧枝开放）4例,眼动脉闭塞4例。结论颈动脉闭塞除了表现为肢体无力外,还可以一过性黑朦及晕厥为主要表现。     

Gender-specific risk of perioperative complications in carotid endarterectomy patients with contralateral carotid artery stenosis or occlusion

Carotid endarterectomy (CEA) has been shown to be effective in stroke prevention in selected patients. Some studies, however, identified gender as an independent risk factor for perioperative CEA complications demonstrating an increased rate of perioperative stroke or death in women. Furthermore, contralateral internal carotid artery (ICA) occlusion has been associated with higher rates of perioperative CEA complications. Therefore, we sought to analyse the gender-specific risk of perioperative CEA complications between patients with or without contralateral ICA stenosis or occlusion. We retrospectively analysed 212 consecutive CEA patients (male = 156, Female = 56) for their gender-specific, perioperative risk of stroke, transient ischemic attack (TIA), restenosis and cardiac complications in the presence (62%) or absence (38%) of a contralateral ICA stenosis/occlusion. In women but not in men, risk of perioperative ischemic events (stroke, TIA) or re-stenosis (p = 0.036) and combined perioperative complications (ischemic events, re-stenosis or cardiac complications; 38.2 % vs. 9.1%; p = 0.028) was significantly increased in the presence of a contralateral ICA stenosis or occlusion. Furthermore, in the presence of a contralateral ICA stenosis/occlusion the number of perioperative ischemic events (p = 0.008) and combined perioperative complications (38.2 % vs. 14.3%; p = 0.006) was significantly higher in female than in male patients. Our study suggests that women with contralateral ICA stenosis or occlusion may have a significantly higher risk for perioperative CEA complications than other subgroups of CEA patients. This risk increase seems to be gender-specific and, if confirmed in larger prospective studies, may influence ICA stenosis therapy in the presence of a contralateral ICA stenosis/occlusion in female patients.     

Cognitive impairment in patients with carotid artery occlusion and ipsilateral transient ischemic attacks

Abstract. Although transient ischemic attacks (TIAs) by definition do not cause lasting neurological deficits, cognitive impairment has been suggested in patients with carotid artery disease who have suffered from a TIA. The purpose of our study was to assess whether patients with carotid artery disease and TIAs are cognitively impaired, to describe the frequency, nature and severity of this impairment, and to search for associated patient characteristics.Thirty-nine consecutive patients with carotid occlusion and ipsilateral cerebral or retinal TIAs, and 46 healthy controls underwent extensive neuropsychological assessment. Performances were compared group-wise with analysis of variance. In addition, the presence of cognitive impairment in the individual patient was determined. Associations between illness characteristics and cognitive impairment were explored with regression analysis.Fifty-four percent of patients were cognitively impaired. Cognitive deficits were non-specific in nature and mild in severity. Impairment occurred also in patients with isolated retinal symptoms and in those without visible ischemic brain lesions on MRI. Neither the presence of any vascular risk factor, the side of the symptomatic carotid occlusion, the uni- or bilaterality of carotid occlusion, nor the number of cerebral ischemic lesions were predictors of cognitive impairment.We conclude that about half of the patients with carotid artery occlusion and ipsilateral TIAs are cognitively impaired. The presence of cognitive deficits in patients with isolated retinal symptoms and in those without cerebral ischemic lesions on MRI argues against an exclusive role for structural brain damage in the pathogenesis of these deficits.     

Neuropsychological deficits in asymptomatic carotid artery stenosis

A total of 20 subjects with asymptomatic carotid artery stenosis (ACAS) and a group of healthy controls were compared as to their cognitive performance. Subjects with ACAS showed substantial deficits on tasks of mental speed, learning, visuospatial abilities, verbal processing and deductive reasoning. The cognitive profile of ACAS--subjects indicated non-specific impairment, possibly related to widespread cerebral vascular disease, of which the presence of ACAS may be one indicator.