Small deep cerebral infarcts associated with occlusive internal carotid artery disease. A hemodynamic phenomenon?

Small deep cerebral infarcts, often referred to as lacunes, have been traditionally associated with small-vessel disease affecting the deep penetrating arterial system. We describe 10 cases where these infarcts were associated with severe, ipsilateral internal carotid artery occlusive disease. Seven of these patients also had severe occlusive disease of the contralateral internal carotid artery. The clinical and radiologic features, in combination with studies of cerebral blood flow, were consistent with hemodynamically mediated cerebral ischemia. Occlusive internal carotid artery disease may be more commonly associated with hemodynamic cerebral ischemia than previously believed, and small cerebral infarcts in the deep arterial border zone areas are likely to be an important manifestation of this process.     

Cerebral arterial compliance in patients with internal carotid artery disease

Background: A decrease in arterial compliance of the internal carotid artery has been associated with an increased risk in ipsilateral ischaemic stroke. However, so far, no technique has been validated to monitor the compliance of intracerebral arteries (Ca) in patients with carotid artery disease. In this study, we sought to monitor Ca in patients with unilateral symptomatic disease and to determine its variations during changes in PaCO₂. Methods: We studied 18 patients with unilateral symptomatic internal carotid artery stenosis >50% or occlusion. Patients underwent monitoring of arterial blood pressure (ABP) and middle cerebral artery cerebral blood flow velocities (CBFV) during baseline, hyperventilation and 5%CO₂ inhalation. Ca was calculated from pulsatile amplitudes of ABP and Cerebral arterial blood volume, extracted from the CBFV waveform using a new mathematical model. Results: At baseline, the decrease in Ca on the diseased side was correlated with the degree of stenosis (r = −0.35; P = 0.01). During hypocapnia, Ca was lower compared to baseline on the normal side (P = 0.004) and on the diseased side (P = 0.04). Ca reactivity, reflecting the changes in Ca per changes in 1 mmHg PaCO₂, was lower on the diseased side between baseline and hypocapnia (3.4 vs. 2.6%; P = 0.04). During hypercapnia, no changes in Ca on the diseased (P = 0.8) nor on the normal sides (P = 0.2) were observed. Conclusions: The decrease in cerebral arterial compliance the side of stenosis/occlusion was correlated with the severity of the internal carotid artery disease. Further studies are needed to determine whether Ca may improve the prediction of ischaemic events in symptomatic and asymptomatic patients.     

Alzheimer's disease with and without cerebral infarcts

OBJECTIVE: To compare the clinical and pathological features of Alzheimer's disease (AD) patients with and without associated cerebral infarcts (CI). METHODS: The consecutive records of 57 prospectively studied demented patients fulfilling the CERAD criteria for the pathological diagnosis of AD were reviewed. Cases with cortical Lewy bodies were excluded. CI were found in 22 cases (39%) (AD+CI group): large infarcts (5), lacunes (13) and/or hippocampal sclerosis (4), and were absent in 35 cases (AD group). Microscopic infarcts, cribiform change, amyloid angiopathy, and white matter rarefaction were not considered in this classification, but were quantified. Cortical atrophy, neurofibrillary tangle and senile plaque (diffuse and neuritic) load were also measured. Pathological evaluation was independent of clinical information. Clinical and pathological data were compared between both groups. RESULTS: AD+CI cases were significantly older, more commonly female, less educated, and more often had blue collar occupations, sleep disturbances, frontal release signs, and EEG spikes than AD cases. Other differences found (acute/subacute onset, behavioral disturbances, and leukoaraiosis on CT scan) disappeared after controlling for age. The frequency of known vascular risk factors and focal motor and sensory signs did not differ between the groups, which showed remarkable clinical similarity overall. The only significant differences on pathological exam were hippocampal microinfarcts and white matter lesions, although there was a trend for lower neurodegenerative lesion load in the AD+CI group. The ischemic lesions were located in temporal lobe in 50% of AD+CI patients; these cases had a significantly lower neocortical neurodegenerative lesion load than those with CI in other sites. CONCLUSIONS: The presence of CI in AD increases significantly with age, but has scarce influence on the clinical features, and cannot be predicted from common vascular risk factors. In spite of a trend, there are no major differences in neurodegenerative lesion load between AD and AD+CI groups, except when CI are located in the temporal lobe (including hippocampus), suggesting that this location may be important in the physiopathology of mixed vascular and AD dementia.     

Site and pathogenesis of infarcts associated with carotid endarterectomy

We analyzed perioperative strokes in 658 carotid endarterectomies with the purpose of explaining the pathogenesis from the morphologic aspect of the infarct on cerebral computed tomograms. All endarterectomies were performed with continuous electroencephalographic monitoring. Of the 42 ischemic strokes (6.4% of all endarterectomies), 34 could be studied. Seven infarcts were hemodynamically induced (five watershed infarcts, two patients with bilateral ischemia); all seven occurred during surgery. Twenty-three of the remaining 27 infarcts were within the territory of the middle cerebral artery (20) or anterior cerebral artery (three) and were probably of thromboembolic origin; 13 of these 23 occurred during surgery (57%). If intraoperative stroke was heralded by permanent electroencephalographic changes, these were not related to the moment of cross-clamping. In four patients the computed tomogram was normal. We believe these facts favor the hypothesis that thromboembolism is the most important factor in the pathogenesis of perioperative stroke associated with carotid endarterectomy under conditions of optimal cerebral monitoring.     

Fenestration of the internal carotid artery associated with arterial dissections.

An increasing number of cases with fenestration that is frequently associated with aneurysms have been reported, largely in the vertebral and basilar arteries and less commonly in the middle and anterior cerebral arteries by angiography as well as by autopsy. However, the anomaly of the internal carotid artery associated with bilateral arterial dissections is exceedingly rare. This represents the first reported case of fenestration of the internal carotid artery associated with arterial dissections. The embryological basis and clinical significance of this anomalous condition are discussed and treatment for arterial dissection is presented.     

Management of tandem internal carotid and middle cerebral arterial occlusions with endovascular multimodal reperfusion therapy

The aim of this study was to evaluate the safety and efficacy of multimodal reperfusion therapy (MMRT) for tandem internal carotid artery and middle cerebral arterial (TIM) occlusions. Cases of TIM occlusion were collected and retrospectively reviewed. The analyzed objects included etiology, sites of tandem occlusion, collateral flow, location and size of infarcts. Combined with mechanical recanalization techniques and its complications, the National Institute of Health Stroke Scale (NIHSS) score and imaging data that was derived pre- and post-procedure were further contrasted. The study enrolled six patients with TIM occlusions. The mean NIHSS score on admission was 17 (range 13–20) and the median time from puncture to recanalization was 141 min (range 60–230). The substantial recanalization rate (Thrombolysis in Cerebral Infarction 2b or 3) was 83.3% and no symptomatic intracerebral hemorrhage was observed. The mean NIHSS score after three days was 14 (range 10–19) and 9 (range 3–17) following discharge. However, one patient died of pulmonary infection one month after discharge. For the five patients who survived, the modified Rankin Scale was evaluated at three months, with scores of 3, 1, 3, 5 and 3, respectively. It is concluded that endovascular therapy for acute TIM occlusions are complex, MMRT may be relatively safe and effective.     

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.     

颈内动脉扭曲与脑缺血的相关性研究

目的研究颈内动脉扭曲与脑缺血的相关性,探讨脑缺血的危险因素。方法回顾性分析存在颈内动脉扭曲但无椎动脉扭曲患者51例(实验组),选取无颈内动脉及椎动脉扭曲患者45例为对照组;比较实验组和对照组脑缺血的发生率;对研究资料进行单因素和多因素回归分析。结果实验组脑缺血发生率明显高于对照组,差异有统计学意义(χ2=51.6,P=0.001)。年龄与脑缺血呈正相关(P=0.008)、动脉狭窄与脑缺血呈正相关(P=0.023)、动脉扭曲与脑缺血存在相关可能性(P=0.055)。动脉扭曲和动脉狭窄是脑缺血的危险因素(P=0.009,P=0.002),但年龄不是脑缺血的危险因素(P=0.107)。结论颈内动脉扭曲是脑缺血的危险因素之一,应列入临床干预的对象中。     

Bilateral occipital infarcts associated with carotid atherosclerosis and a persistent hypoglossal artery

The persistent hypoglossal artery (PHA) is the second most common persistent embryological carotid-basilar connection and usually represents an incidental finding in cerebral arteriograms. The hypoglossal artery connects the primordial carotid artery with the longitudinal neural arteries, which later form the basilar artery. The PHA leaves the internal carotid artery as an extracranial branch, enters the skull through the anterior condyloid foramen, the hypoglossal canal and joins the caudal portion of the basilar artery. We report magnetic resonance and digital subtraction angiography findings in the first case of bilateral occipital infarctions associated with PHA and carotid atherosclerosis. The probable mechanism underlying bilateral occipital infarcts was embolism from the carotid territory to the posterior cerebral arteries. PHA may present a challenge in diagnosis and management of patients with carotid atherosclerosis and vertebrobasilar ischemia.     

Bilateral hypoplastic internal carotid arteries with multiple cerebral aneurysms

A 60-year-old man with massive subarachnoid hemorrhage is reported. Radiologically, bilateral occlusion of the internal carotid arteries and multiple cerebral aneurysms of the saccular type were detected. Postmortem examination revealed that the internal carotid arteries were markedly diminutive and completely occluded by mesenchymal fibrous tissue. The pathogenesis of the diminutive internal carotid arteries and the cerebral aneurysms were briefly discussed.