Contralateral Anterior Cerebral Artery Research Articles

Rare complication characterized by late-onset transient neurological symptoms without hyperperfusion after carotid artery stenting: A report of three cases

We experienced a rare complication after carotid artery stenting (CAS) characterized by transient neurological symptoms with no evidence of distal emboli or hyperperfusion. Using neuroimaging, we investigated the pathogenesis of the complication that occurred after CAS in three patients who developed neurological symptoms over a period of ten hours after CAS and improved within two days. None of the three patients showed signs of fresh infarctions on diffusion-weighted imaging or hyperperfusion on single-photon emission computed tomography. However, high signal intensity was observed in the leptomeningeal zone of the cerebral hemisphere on the stent side in all three patients and in the leptomeningeal zone of the contralateral anterior cerebral artery territory in one patient. These areas were assessed using fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging without gadolinium administration. The high signal intensity in the leptomeningeal zone disappeared as the symptoms improved. Based on the transient nature of the neurological disorders and the normalization of FLAIR imaging findings in these patients, the pathogenesis of this complication might have been vasogenic edema due to vasoparalysis of the local vessels caused by the hemodynamic changes occurring after CAS.

Carotid Artery Stenting Improves Cerebral Hemodynamics Regardless of the Flow Direction of Ophthalmic Artery

We enrolled 221 patients with elective carotid artery stenting (CAS). Patients with contralateral carotid stenosis exceeding 50%, insufficient vertebral artery (VA) flows, or angioplasty at subclavian artery were excluded. All patients underwent serial cerebral ultrasound studies. Of the 116 included patients, the direction of ophthalmic artery (OA) flow was forward in 74 patients while reversed in 42. The reversed flow group had worse ipsilateral stenosis, higher hemoglobin, and cardiac output. After CAS, the reversed flow group had an immediate recovery of ipsilateral internal carotid artery flow volume (FV; P < .0001), time average velocity (TAV) of middle cerebral artery (P = .02), and normalization of OA flow. The forward flow group had gradual decrement in TAV of contralateral anterior cerebral artery (P = .01) and total FV of VA (P = .001). Our results suggest CAS improves cerebral hemodynamics through different ways regardless of the direction of OA flow.

Postoperative Increase in Cerebral White Matter Fractional Anisotropy on Diffusion Tensor Magnetic Resonance Imaging Is Associated With Cognitive Improvement After Uncomplicated Carotid Endarterectomy

Carotid endarterectomy (CEA) might improve cognitive function. Fractional anisotropy (FA) values in the cerebral white matter derived from diffusion tensor magnetic resonance imaging (DTI) correlate with cognitive function in patients with various central nervous system diseases. To use tract-based spatial statistics to determine whether postoperative changes of FA values in the cerebral white matter derived from DTI are associated with cognitive improvement after uncomplicated CEA. In 80 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≥70%), FA values in the cerebral white matter were derived from DTI before and 1 month after surgery and were analyzed by using tract-based spatial statistics. Neuropsychological testing, consisting of the Wechsler Adult Intelligence Scale Revised, the Wechsler Memory Scale and the Rey-Osterreith Complex Figure test, was also performed preoperatively and after the first postoperative month. Based on the neuropsychological assessments, 11 (14%) patients were defined as having postoperatively improved cognition. The difference between the 2 mean FA values (postoperative values minus preoperative values) in the cerebral hemisphere ipsilateral to surgery was significantly associated with postoperative cognitive improvement (95% confidence intervals, 2.632-9.877; P = .008). White matter FA values in patients with postoperative cognitive improvement were significantly increased after surgery in the whole ipsilateral cerebral hemisphere, in the contralateral anterior cerebral artery territory, and in the watershed zone between the contralateral anterior and middle cerebral arteries. Postoperative increase in cerebral white matter FA on DTI is associated with cognitive improvement after uncomplicated CEA.

Bilateral atherosclerotic internal carotid artery occlusion causing acute bihemispheric infarctions

Multiple acute brain infarctions in both cerebral hemispheres involving the anterior circulation are uncommon (affecting less 1.0–6.0 % of acute stroke patients) and usually suggest an embolic mechanism, particularly one of aortic or cardiac origin [1–4]. Unilateral internal carotid artery (ICA) atherosclerotic lesions may rarely cause acute bihemispheric infarctions through crossflow in the anterior communicating artery with the contralateral anterior cerebral artery (ACA) territory being invariably involved in all described cases [4]. To the best of our knowledge there has been no report of bilateral extracranial atherothrombotic ICA occlusion causing acute bihemispheric infarctions involving both middle cerebral artery territories. A 73-year-old man with a history of hypertension, hypercholesterolemia and smoking presented with an acute right upper arm weakness that he noticed on awakening. Admission brain CT and electrocardiogram were normal. Neurological examination disclosed a mild left hemipareris and left-side visual neglect with an NIH Stroke Scale score (NIHSS-score) of 5 points. The patient underwent emergent carotid duplex evaluation showing multiple hyperechoic plaques in both common carotid arteries (CCA) and acute bilateral ICA occlusion (Fig. 1a, b). Transcranial Doppler examination showed (1) acute bilateral middle cerebral artery (MCA) occlusion with minimal flow (thrombolysis in brain ischemia grade I) in right and blunted flow (thrombolysis in brain ischemia grade II) in left MCA, (2) present collateral flow through reversed ophthalmic artery (OA) bilaterally and (3) absent collateral flow through posterior communicating arteries. The patient also underwent 30-min bilateral transcranial doppler monitoring that documented the presence of microembolic signals in both MCAs (Fig. 2). Acute reperfusion therapies including intravenous or intra-arterial thrombolysis as well as mechanical thrombectomy were withheld because of unknown time of stroke onset. Emergent echocardiography excluded the presence of cardiac thrombus and other source of cardiogenic embolism (including aortic arch dissection). He was treated with aspirin (325 mg) and enoxeparin (40 mg). Fourteen hours later, he became quadriplegic and lethargic (NIHSS-score 26 points). Repeat brain CT (performed after 12 h from the baseline CT) showed bilateral cortical infarctions (Fig. 1c, d) in both MCA territories (arrowheads). The patient expired the following day. Simultaneous occurrence of multiple infarcts in different arterial territories is a characteristic feature of cardioembolic stroke according to the findings of recent studies G. Tsivgoulis (&) I. Heliopoulos K. Vadikolias M. Flamouridou S. Tsakaldimi C. Piperidou Department of Neurology, University Hospital of Alexandroupolis, Democritus University of Thrace, Kapodistriou 3, Nea Xili, Alexandroupolis 68100, Greece e-mail: tsivgoulisgiorg@yahoo.gr

MSCT diagnosis of aneurysms associated with an unusual variant: atypical triplication anterior cerebral artery

Atypical triplication anterior cerebral artery is a rare entity and the variation is an important factor leading to aneurysm. A patient with aneurysm that arises from the bifurcation of the distal anterior cerebral arteries is presented. The contralateral anterior cerebral artery is also presented, and there is no communication between the left and the right anterior cerebral artery. The findings from multiple slice CT angiography in this case are illustrated and discussed. The recognition of this variant is important for the therapy planning.

The Prediction of Contralateral Progression in Children and Adolescents With Unilateral Moyamoya Disease

To evaluate the factors predictive of contralateral progression in children and adolescents with unilateral moyamoya disease (MMD), the authors retrospectively analyzed clinicoradiological findings. The records of 394 consecutive patients with MMD aged 0 to 17 years were reviewed. Unilateral MMD was defined based on the typical angiographic findings of MMD in 1 hemisphere and no abnormality in the contralateral internal carotid artery and the middle cerebral artery. Of the 394 patients with MMD, 45 (11.4%) had unilateral MMD and the prevalence increased with age. Untreated contralateral hemispheres were followed by serial MR angiography. Follow-up angiography was performed if contralateral progression, defined as any noticeable change in the contralateral internal carotid artery and/or middle cerebral artery, was suggested by MR angiography. Eight of the 45 (17.8%) had angiographically documented progression over a mean follow-up of 53.4 months. Mean time to contralateral progression was 27 months (range, 21 to 37 months). An age at diagnosis of <9 years was found to be the only independent predictor of contralateral progression (P=0.025), which persisted despite adjustment for sex and ipsilateral Suzuki stage (hazard ratio, 8.26; 95% CI, 1.01 to 67.94). Other factors, including abnormalities in the contralateral anterior cerebral artery, were not found to be predictive of progression to bilateral MMD. The incidence of contralateral progression in our cohort of children and adolescents with unilateral MMD appears to be lower than those previously reported. Furthermore, contralateral progression tended to occur in children aged <9 years within 3 years of initial diagnosis (32%).

Stellate ganglion block for treatment of cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage - A preliminary study

Background:Stellate ganglion block improves cerebral perfusion by decreasing the cerebral vascular tone. Its effects on cerebral vasospasm to relieve neurological deficits have not been evaluated. This prospective observational study was carried out to evaluate the effect of stellate ganglion block on cerebral hemodynamics in patients with symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage.Materials and Methods:Fifteen patients of either sex, aged 18-75 years, who underwent surgical clipping of aneurysm and developed refractory cerebral vasospasm were included. Stellate ganglion block was performed using 10 ml of bupivacaine 0.5% on the side with maximum cerebral blood flow velocity. Neurological status, cerebral blood flow velocity and pulsatility index were assessed before and 10 minutes, 30 minutes, 2 hours, 6 hours, 12 hours and 24 hours after stellate ganglion block.Results:Improved Glasgow coma score was observed 30 minutes after stellate ganglion block. Neurological deficits reduced in 11 patients. Ipsilateral middle cerebral artery mean flow velocity decreased from 133.66 cm/sec before stellate ganglion block to 110.53 cm/sec at 6 hours (P<0.001) and 121.62 cm/sec at 24 hours (P<0.001) after stellate ganglion block. There was a decrease in ipsilateral anterior cerebral artery mean flow velocity after stellate ganglion block (P<0.001), which persisted for 12 hours. A decline in flow velocities was observed in contralateral middle cerebral artery (P=0.008) and anterior cerebral artery (P=0.041) for 12 hours.Conclusion:This study suggests stellate ganglion block to be an effective modality of treatment for refractory cerebral vasospasm after aneurysmal subarachnoid hemorrhage.

Mechanism of Moyamoya Vessels Secondary to Intracranial Atherosclerotic Disease: Angiographic Findings in Patients with Middle Cerebral Artery Occlusion

Moyamoya vessels, which form a fragile collateral vascular network at the base of the brain, are associated with moyamoya disease and moyamoya syndrome. The mechanisms involved in their development remain unknown. This study evaluated the angiographic findings of the collateral vasculature in patients with moyamoya vessels secondary to atherosclerotic middle cerebral artery (MCA) occlusion. The study population comprised 26 patients with chronic atherosclerotic unilateral MCA occlusion who underwent digital subtraction angiography. We evaluated the presence of moyamoya vessels and intracranial arterial lesions and the degree of leptomeningeal anastomosis. We divided the patients into two groups, those with and those without moyamoya vessels, and compared clinical backgrounds and angiographic findings between the groups. Of the 26 patients, 17 had moyamoya vessels. The presence of moyamoya vessels was associated with ipsilateral or contralateral anterior cerebral artery stenosis to the occluded MCA (P = .004) and poor development of anterior leptomeningeal anastomosis (P = .012). It also was associated with vascular lesions involving more than one intracranial branch vessel in patients with moyamoya syndrome secondary to atherosclerosis. Our findings suggest that moyamoya vessels might be compensatory collateral vessels associated with poorly developed leptomeningeal collateral vessels.

Fusiform Aneurysm of the Proximal Anterior Cerebral Artery (A1)

Fusiform aneurysms of the A1 segment of the anterior cerebral artery (ACA) are exceptional, with only 15 reported cases. This article presents an additional case treated by microsurgical trapping. The aim is to discuss the treatment of these aneurysms based on the aneurysm morphology and the anatomy of the ACA complex. A 52-year-old woman with subarachnoid hemorrhage (Hunt-Hess grade II) showed an aneurysm of the proximal part of the A1 segment of the left ACA involving the whole circumference of the arterial wall on computerized tomography angiography and digital angiography. There was good collateral blood flow from the right ACA to the distal left ACA. A left pterional craniotomy allowed us to expose a large aneurysm of the proximal part of the A1 segment; the artery entered into the aneurysm sac and could not be identified at the level of the aneurysm. Trapping of the aneurysm was performed with a distal clip placed just before the origin of the artery of Heubner. No neurological deficits were observed postoperatively. Clipping of fusiform aneurysms of the A1 segment using an encircling clip is the treatment of choice but, more often, this is impossible. Trapping of the aneurysm with preservation of the perforating branches (mainly the Heubner artery) may be easily performed when collateral blood flow from the contralateral ACA is sufficient.

Changes in Blood Flow of Anterior and Middle Cerebral Arteries Following Carotid Endarterectomy: A Transcranial Doppler Study

The aim of the present study was to evaluate the changes in blood flow of anterior and middle cerebral arteries following carotid endarterectomy, using transcranial Doppler (TCD) flow studies. This study included 100 patients (72 men, mean age 65 years) who underwent carotid endarterectomy because of high-grade carotid stenosis or symptoms of ischemic stroke. Endarterectomy was performed by a distal shunt between the common carotid and internal carotid arteries. Blood flow in the anterior and middle cerebral arteries was assessed by TCD preoperatively and also in the postoperative period (1st and 4th day; 1st, 6th, and 12th month). Collateral circulation in the Willis circle was evaluated by common carotid compression. Patients with bilateral carotid stenosis > or =70% exhibited a significantly increased flow velocity in the ipsilateral anterior cerebral artery (ACA), middle cerebral artery (MCA), and in the contralateral ACA. Patients with entirely occluded contralateral internal carotid artery showed the most pronounced changes in cerebral hemodynamics. Blood flow velocities returned to the preoperative values at 1 to 12 months following endarterectomy. Hyperperfusion syndrome was manifested in 14 patients, who exhibited significantly higher flow velocities in the ipsilateral MCA compared with asymptomatic patients. A transient bilateral increase of blood flow velocity in the anterior part of the Willis circle may often occur in the immediate postoperative period following carotid endarterectomy. Although its clinical significance is not entirely understood, this increase may be associated with cerebral hyperperfusion syndrome.

Reduced modelling of blood flow in the cerebral circulation: Coupling 1‐D, 0‐D and cerebral auto‐regulation models

AbstractPulsatile blood flow in the cerebral circulation is simulated using a nonlinear, one‐dimensional model of the arterial haemodynamics coupled in the time domain with lumped parameter and flow auto‐regulation models of the perfusion of the microcirculation. A linear analysis of the coupling shows that a resistance equal to the characteristic impedance of the blood vessel is required at the inflow of a terminal windkessel model to avoid the generation of non‐physiological wave reflections. The cerebral model suggests that the worst anatomical variation of the circle of Willis in terms of restoring normal cerebral flows after a sudden carotid occlusion is a circle without the first segment of the contralateral anterior cerebral artery. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Persistent trigeminal artery and associated vascular variations

Persistent trigeminal artery (PTA) is the most frequent type of persistent primitive carotid-basilar artery anastomoses. Persistent trigeminal artery is usually associated with small or absent posterior communicating artery (Pcom). It may also be associated with hypoplastic vertebral and basilar arteries. Patients may present with symptoms related to hypo-perfusion of posterior circulation or microembolization from carotid artery to posterior circulation. We are presenting a 60-year-old who had recurrent episodes of vertigo and parasthesia, in whom MR angiography revealed a medial, Saltzman type 1 PTA on the left with absent ipsilateral Pcom, duplicated ipsilateral superior cerebellar artery, hypoplastic A1 segment of contralateral anterior cerebral artery (ACA), azygous ACA and hypoplastic ipsilateral vertebral artery.

Steal phenomenon through the anterior communicating artery in Moyamoya disease

Branch occlusion of the anterior cerebral artery (ACA) is regarded as a part of Moyamoya disease. The purpose of this study is to define the ACA steal phenomenon (SP) in Moyamoya disease and to evaluate temoporal changes according to the disease progression. From 139 Moyamoya patients we defined ACASP as narrowing of the ipsilateral A1-2 junction while preserving the anterior communicating artery and supplying the contralateral ACA cortical branches with the development of leptomeningeal collaterals by the ipsilateral middle cerebral artery into the hypoperfused ipsilateral ACA territory. Direction of the steal related to the stage in both hemispheres by Suzuki classification was statistically analyzed using the binomial test based on binomial distribution. Follow-ups of ACASP were evaluated in five patients. We identified ACASP in 13 (9%) patients (male:female=7:6, mean age 18 years, range: 2-58 years) of the 139 study patients. The presenting pattern was ischemic in 12 and hemorrhagic in one. The direction of SP occurred from the hemisphere in the lower to the higher stage of Suzuki classification (two-tail P value=0.0002). After revascularization surgery, ACASP disappeared or diminished. ACASP may occur in bilaterally different stages of Moyamoya disease as a transient self-adaptive process. It regresses after revascularization surgery.

Progression of Unilateral Moyamoya Disease: A Clinical Series

Background: The natural history of unilateral moyamoya disease (MMD) in adult patients is not clearly described in the literature. We present a series of 18 patients with unilateral MMD and analyze the risk factors for progression to bilateral disease. Methods: A retrospective review of 157 MMD patients treated at Stanford University Medical Center from 1991 to 2005 identified 28 patients with unilateral MMD (defined as none, equivocal or mild involvement on the contralateral side). Results: Eigh teen patients (5 males and 13 females) were identified with unilateral MMD and angiographic follow-up of ≧5 months. Mean radiologic follow-up (± standard error of the mean) was 19.3 ± 3.4 months and mean clinical follow-up was 24.5 ± 3.7 months. Five patients had childhood onset MMD and 13 patients had adult onset disease. Angiographic progression from unilateral to bilateral disease was seen in 7 patients (38.9%) at a mean follow-up of 12.7 ± 2.4 months. Four of the 7 patients had significant clinical and radiologic progression requiring surgical intervention. Five of 7 patients that progressed had adult onset MMD. The presence of equivocal or mild stenotic changes of the contralateral anterior cerebral artery (ACA), middle cerebral artery (MCA) or internal carotid artery (ICA) was an important predictor of progression (p < 0.01); 6 of 8 patients (75%) with equivocal or mild contralateral disease progressed, whereas only 1 of 10 patients (10.0%) with no initial contralateral disease progressed to bilateral MMD. One patient had mild or equivocal MCA, ICA and ACA stenosis at the time of initial diagnosis and this patient progressed. Conclusions: Contralateral progression in the adult form occurs more commonly than previously reported. The presence of minor changes in the contralateral ACA, intracranial ICA and MCA is an important predictor of increased risk of progression. Patients with a completely normal angiogram on the contralateral side have a very low risk of progression.

Trapping and Vascular Reconstruction for Ruptured Fusiform Aneurysm in the Proximal A1 Segment of the Anterior Cerebral Artery-Case Report-

A 65-year-old woman presented with subarachnoid hemorrhage (SAH). Angiography detected a small bulge in the A1 segment of the right anterior cerebral artery (ACA). The patient was managed conservatively. Ten days after the initial SAH, the patient suffered a second SAH. Cerebral angiography demonstrated a fusiform aneurysm in the right A1 segment and vasospasm in the left A1 segment. The aneurysm of the right A1 segment was trapped and the right superficial temporal artery (STA) was end-to-end anastomosed to the distal portion of the right A1 segment. The patient had no postoperative cerebral ischemic events. Postoperative cerebral angiography revealed that the bypass flow through the right STA perfused the right ACA territories. STA-A1 end-to-end anastomosis can prevent cerebral ischemic events following parent vessel occlusion or microsurgical trapping for fusiform cerebral aneurysms in the A1 segment without sufficient collateral flow to the ipsilateral ACA territory from the contralateral ACA.

Color Doppler Sonographic Evaluation of Collateral Circulation in Patients with Cerebral Aneurysms and the Occlusion of the Brachiocephalic Vessels

The objective of this study was to assess the collateral circulation and blood flow velocity in arteries forming collateral circulation in patients with cerebral aneurysms and the occlusion of the brachiocephalic vessels. Between 1989 and 2004 we examined a group of seven consecutive patients with diagnosed cerebral aneurysm and occlusion of the extracranial artery by means of cerebral angiography, transcranial color-coded sonography (TCCS) and color Doppler sonography of extracranial arteries. The Doppler examination results achieved in this group were compared with the Doppler results of 40 healthy subjects from a control group. Three patients were diagnosed with an occluded innominate artery. In four other cases an occlusion of the extracranial segment of the internal carotid artery was found. The aneurysms were located on intracranial arteries of collateral flow. The innominate artery occlusion resulted in a hemodynamic effect which was a complete vertebral steal and systolic deceleration (in one case) or alternating flow (in two cases) in the right common carotid artery. An additional route of collateral circulation in all these cases led from extracranial carotid branches through the right external carotid artery to the ipsilateral internal carotid artery. In all seven patients, 13 intracranial collateral pathways were examined. In eight of them, including four cases with cerebral aneurysms, an increase in blood flow velocity was observed. In the remaining five cases, including three cases with cerebral aneurysms, the mean blood velocity was within the normal range. The anterior communicating artery (AComA) formed the main intracranial collateral pathway which was found in seven patients, including three patients with diagnosed AComA aneurysm. Blood flow velocity in ipsilateral (on the obstructed side) and contralateral (on the unobstructed side) anterior cerebral artery, as well as pulsatility and resistance indexes in contralateral anterior cerebral and middle cerebral arteries were higher compared with healthy control subjects. In the ipsilateral middle cerebral artery a relative, insignificant decrease of pulsatility and resistance indexes was detected. Ipsilateral and contralateral middle cerebral artery blood flow velocities were lower compared with the control group. Occlusion of the brachiocephalic vessels leads to formation of collateral circulation through the circle of Willis and the extracranial collaterals connecting the external and internal carotid arteries. An increase in blood flow velocity is commonly observed in intracranial arteries forming a collateral pathways. In some cases, not excluding arteries with a cerebral aneurysm, the increase in blood flow velocity is insignificant or none at all. This study shows that formation of a cerebral aneurysm is not always related to an increase in the flow velocity of collateral arteries.

Experimental Model of Intracranial Arteriovenous Shunting in the Acute Stage

A model of intracranial arteriovenous (AV) shunting must incorporate local hypoperfusion and simulate the hemodynamics of arteriovenous malformations. In this study, the hemodynamics of an intracranial AV shunt model in the acute stage were clarified. End-to-side anastomoses with a femoral vein graft were performed between a cortical branch of the middle cerebral artery (MCA) and the superior sagittal sinus in anesthetized dogs. Local cerebral blood flow (l-CBF) was measured by laser Doppler blood flowmetry. l-CBF decreased suddenly by 34.2% when the shunt was opened in the ipsilateral MCA territory. Upon re-occlusion, l-CBF immediately equaled or exceeded the pre-opening value and returned to the pre-opening value within the next 15 minutes. Opening the shunt produced little change in l-CBF in the territory of the ipsilateral or contralateral anterior cerebral artery. The decrease in l-CBF was correlated with shunt volume only in the MCA territory. l-CBF manifested a PaCO(2)-dependent increase before shunt opening, but CO(2) reactivity was impaired after opening the shunt only in the MCA territory. This dog model features local hypoperfusion due to intracranial AV shunting and disturbance of CO(2) reactivity in the acute stage. The hemodynamics of this model will be confirmed in the chronic stage.

Mechanisms of Single and Multiple Borderzone Infarct: Transcranial Doppler Ultrasound/Magnetic Resonance Imaging Correlates

Background and Purpose: Hemodynamic patterns after borderzone (BZ) infarction are variable and dynamic. However, stroke mechanisms in different types of BZ infarctions have not been systematically studied by magnetic resonance angiography (MRA) and transcranial Doppler ultrasonography (TCD). Methods: Forty-nine patients who experienced a stroke limited to the territory of either the superficial or internal borderzone proved on MRI included in our registry, corresponding to 4% of 1,200 patients with ischemic stroke, were studied. All these patients underwent MRA, extracranial Doppler ultrasonography, TCD and other investigations from the standard protocol of our registry. Twenty of them (41%) had a posterior BZ infarct, 14 (29%) an anterior BZ infarct, 10 (20%) a subcortical BZ infarct and 5 (10%) bilateral BZ infarcts. Results: Unilateral internal carotid artery (ICA) tight stenosis or occlusion ipsilateral to the lesion was present in 14 patients (70%) with a posterior BZ infarct, in 72% of those with an anterior BZ infarct, in 80% of those with a subcortical BZ infarct and in 80% of those with bilateral BZ infarcts. TCD showed cross-filling of the middle cerebral artery via the anterior communicating artery in 5 patients (25%) with a posterior BZ infarct and 10% had an increased mean flow velocity (MFV) in the ipsilateral P1 posterior cerebral artery (PCA). In patients with an anterior BZ infarct, 3 (23%) had an MFV increase in the contralateral A1 anterior cerebral artery (ACA), and 2 (15%) had a higher MFV in the ipsilateral PCA. An elevated velocity at midline depths with reversed A1 ACA flow direction was seen in 2 patients (20%) with a subcortical infarct, and 1 patient (10%) had an MFV increase in the ipsilateral P1 PCA. Left ventricular systolic dysfunction (ejection fraction <40%) was present in 50% of patients with a posterior BZ infarct, in 36% of those with an anterior BZ infarct, in 20% of those with a subcortical BZ infarct and bilateral BZ infarcts each. Conclusion: The association of severe ICA stenosis or occlusion with cardiopathies and left ventricular dysfunction may play a critical role in those with BZ infarcts having inadequate collateral supply, while a cardioembolism or acute ICA dissection may also cause BZ infarction due to the rapidity of the occlusive process and the inability of the cerebral vasculature to recruit collateral pathways quickly enough.

Frequency and predictors for angiographically improved inflow of contrast medium after carotid angioplasty and stenting.

Percutaneous transluminal carotid angioplasty and stenting (PTAS) can result in immediate improvement in cerebral blood flow (CBF) evident through faster transit of contrast medium on angiography. To evaluate frequency and predictors of changes in inflow of contrast medium before and after PTAS, we reviewed 86 patients (mean age 68.6 +/- 9.1 years) treated for symptomatic or asymptomatic carotid stenosis. Clinical data and lesion characteristics were extracted from charts and digital angiograms, respectively. Perfusion change was assessed qualitatively by comparing pre- and poststenting images matched for projection and time from injection. Improved inflow was defined on the basis of spatial or temporal distribution of contrast medium: grade -1: fewer vessels visible after stenting; 0: no change; 1: more distal small arteries visible; 2: time-matched poststenting image showing a capillary blush; 3: time-matched poststenting image showing small veins, 4 time-matched poststenting image showing large veins and sinuses. Faster inflow of contrast medium was observed in 74% of patients (grades 1: 34%,and 4: 4.7%). In linear regression analysis, higher degrees of ipsilateral stenosis were associated with greater changes in inflow of contrast medium (P < 0.05). Right internal carotid lesions were associated with greater change in inflow than left-sided lesions (P < 0.01). In 31 patients (36%) we initially showed contralateral anterior cerebral artery (ACA) filling, and in 39% of these, normal filling was restored after stenting. Lesser contralateral carotid stenosis was associated with crossed ACA filling and with restoration of normal filling pattern after stenting. Faster appearance of a contrast-medium blush is seen in most cases of carotid angioplasty and stenting and depends on the degree of hemodynamic inflow obstruction relieved by stenting.

Cerebral blood flow in relation to contralateral carotid disease, an MRA and TCD study.

to describe redistribution of cerebral blood flow in patients with severe internal carotid artery (ICA) stenoses in relation to contralateral ICA disease. sixty-six patients scheduled for carotid endarterectomy (CEA) were grouped according to severity of contralateral stenosis (<30% [group I]; 30-69% [group II]; 70-99% [group III]; occlusion [group IV]. Transcranial Doppler (TCD) and magnetic resonance angiography (MRA) investigations were performed preoperatively. TCD demonstrated a reversed flow in the contralateral anterior cerebral artery (A(1)segment) and ophthalmic artery in three-quarters of group IV patients (p <0.0001). Group IV patients also exhibited decreased blood flow velocity in the contralateral middle cerebral artery (p =0.001). MRA showed increased ipsilateral ICA and basilar artery (BA) blood flow volumes (Q-flows) in group IV patients when compared to the other groups (p <0.001). No changes in total Q-flow (ICAs+BA) were found. in patients considered for CEA, the severity of the contralateral ICA disease is an important determinant of the pattern of blood flow redistribution through the anterior communicating pathway and ophthalmic artery. Significant flow redistribution through the posterior communicating pathway occurs especially in patients with contralateral ICA occlusion.