Internal Carotid Artery Occlusive Disease Research Articles

Lesion patterns and mechanism analysis of acute contralateral ischemic stroke accompanyingstenosis of unilateral extracranial internal carotid artery.

Previous studies on unilateral internal carotid artery occlusive disease have focused on the mechanisms of ipsilateral hemispheric stroke, and contralateral stroke is considered to be an accidental phenomenon. Little is known about the relationship between severe stenosis (including occlusion) of the unilateral extracranial segment of the internal carotid artery and contralateral cerebral stroke, and the infarct patterns and pathogenesis require further study. The purpose of this study was to investigate the clinical characteristics and pathogenesis of contralateral acute stroke with unilateral extracranial internal carotid artery stenosis (including occlusion). Thirty-four patients were enrolled in this study, and all patients underwent routine clinical evaluation, including medical history, physical examination, laboratory tests, and various imaging evaluations. The morphological characteristics of diffusion-weighted magnetic resonance imaging were applied to determine infarct patterns. The etiological classification was confirmed according to the TOAST classification. There were six distinctive lesion patterns: small subcortical infarcts (six patients), large subcortical infarcts (one patient), diffuse infarcts (eight patients), multiple anterior circulation infarcts (eight patients), multiple posterior circulation infarcts (two patients), and multiple anterior and posterior circulation infarcts (nine patients). Diffuse and multiple infarcts were the most common topographic patterns in ischemic stroke contralateral to internal carotid artery stenosis or occlusion. Hemodynamic impairment of the contralateral hemisphere due to hypoperfusion and blood theft is regarded as the basis of stroke occurrence. Low ischemic tolerance and embolism are the maincauses of acuteischemicstroke.

Factors Influencing Long-Term Blood Flow in Extracranial-to-Intracranial Bypass for Symptomatic Internal Carotid Artery Occlusive Disease: A Quantitative Study.

Maintaining the patency of extracranial-to-intracranial (EC-IC) bypass is critical for long-term stroke prevention. However, reports on the factors influencing long-term bypass patency and quantitative assessments of bypass patency are limited. To quantitatively evaluate blood flow in EC-IC bypass using four-dimensional (4D) flow magnetic resonance imaging (MRI) and investigate factors influencing the long-term patency of EC-IC bypass. Thirty-six adult Japanese patients who underwent EC-IC bypass for symptomatic internal carotid or middle cerebral artery occlusive disease were included. We examined the relationships between decreased superficial temporal artery (STA) blood flow volume and perioperative complications, long-term ischemic complications, patient background, and postoperative antithrombotic medications in patients for whom STA flow could be quantitatively assessed for at least 5 months using 4D flow MRI. The mean follow-up time was 54.7 ± 6.1 months. One patient presented with a stroke during the acute postoperative period that affected postoperative outcomes. No recurrent strokes were recorded during long-term follow-up. Two patients died of malignant disease. Seven cases of reduced flow occurred in the STA, which were correlated with single bypass (P = .0294) and nonuse of cilostazol (P = .0294). STA occlusion was observed in 1 patient during the follow-up period. Hypertension, age, smoking, dyslipidemia, and diabetes mellitus were not correlated with reduced blood flow in the STA. Double anastomoses and cilostazol resulted in long-term STA blood flow preservation. No recurrence of cerebral infarction was noted in either STA hypoperfusion or occlusion cases.

Ischemic Stroke Revascularization.

Extracranial-intracranial (EC-IC) bypass is one of the most fundamental techniques for ischemic cerebrovascular disease (CVD). We describe the standard surgical strategies, advanced techniques, and controversies concerning revascularization of ischemic stroke. The standard surgical strategies and techniques emphasize how to determine surgical indication, which should be decided for symptomatic internal carotid artery or middle cerebral artery (MCA) occlusive disease with misery perfusion detected by quantitative single photon emission computed tomography. Advanced techniques are available for complex situations such as posterior circulation revascularization, Bonnet bypass for common carotid artery obstruction, and various EC-IC bypasses for ischemia in the MCA and/or anterior cerebral artery territories using inter-grafts such as femoral veins and radial arteries, illustrated by our surgical results and experiences. Controversies include endovascular treatment complementary to EC-IC bypass. Finally, we advocate emergent EC-IC bypass for progressive ischemic CVD, particularly for contraindication or unsuccessful treatment after intravenous tissue plasminogen activator administration and/or endovascular thrombolysis. EC-IC bypass surgery can be reliable for ischemic CVD under strict optimal surgical indications using safe and reliable surgical techniques.

Microstructural Alterations Analogous to Accelerated Aging of the Cerebral Cortex in Carotid Occlusive Disease

PurposeTo investigate cortical thickness and cortical quantitative T2 values as imaging markers of microstructural tissue damage in patients with unilateral high-grade internal carotid artery occlusive disease (ICAOD).MethodsA total of 22 patients with ≥70% stenosis (mean age 64.8 years) and 20 older healthy control subjects (mean age 70.8 years) underwent structural magnetic resonance imaging (MRI) and high-resolution quantitative (q)T2 mapping. Generalized linear mixed models (GLMM) controlling for age and white matter lesion volume were employed to investigate the effect of ICAOD on imaging parameters of cortical microstructural integrity in multivariate analyses.ResultsThere was a significant main effect (p < 0.05) of the group (patients/controls) on both cortical thickness and cortical qT2 values with cortical thinning and increased cortical qT2 in patients compared to controls, irrespective of the hemisphere. The presence of upstream carotid stenosis had a significant main effect on cortical qT2 values (p = 0.01) leading to increased qT2 in the poststenotic hemisphere, which was not found for cortical thickness. The GLMM showed that in general cortical thickness was decreased and cortical qT2 values were increased with increasing age (p < 0.05).ConclusionUnilateral high-grade carotid occlusive disease is associated with widespread cortical thinning and prolongation of cortical qT2, presumably reflecting hypoperfusion-related microstructural cortical damage similar to accelerated aging of the cerebral cortex. Cortical thinning and increase of cortical qT2 seem to reflect different aspects and different pathophysiological states of cortical degeneration. Quantitative T2 mapping might be a sensitive imaging biomarker for early cortical microstructural damage.

Computed Angiography in Assessment of Critical Occlusive Carotid Disease – Ability to Observe Different Types of Pathology: Critical Stenosis, Near-occlusion and Local Occlusion with Distal Collateral Supply Through Atypical Ascending Pharyngeal Artery

Introduction: The pathologies that correspond to almost terminal occlusion of internal carotid artery (ICA) can vary a lot. Several types were described - critical stenosis, near-occlusion and local occlusion of the artery. Differential diagnosis between them could be achieved with assessment of upper artery segments. Thus aim of our study was to assess computed angiography (CTA) abilities in analysis of internal carotid artery critical atherosclerotic changes. Methods: During 2016-2018 years 323 patients underwent examination (ultrasound and CTA of brachiocephalic arteries) prior to surgical treatment of ICA occlusive disease. CTA was made on Philips iCT 256 slices (noncontrast, arterial and venous phases) with 50 ml on nonionic contrast media injected at rate of 4-4,5 ml/sec. We distinguished several types of ICA changes: stenosis more than 60% and 70%, critical stenosis, near-occlusion (also with distal collapse), local occlusion. Results: From all patients ICA stenosis up to critical level was observed in 104 patients. Cases with only critical narrowing of ICA at atherosclerotic lesion level and normal distal portion were described as critical stenosis (Fig. 1a, Fig. 2a) - 84 patients (26% of all observed cases). Cases with critical narrowing at atherosclerotic plague level and diffuse decrease of upper segments were detected as near-occlusion (Fig. 1b, Fig. 2b) - in 18 cases (5,6% of cases). In 2 patients we were able to observe local occlusion of ICA in the bulbus with distal circulation through atypical ascending pharyngeal artery (Fig. 1c, Fig. 2c). No cases with congenital hypoplasia were detected. In patients with diffuse decrease of upper ICA segments all elements of the circle of Wills were detected in 70% of cases. During surgery CTA results were confirmed, but atherosclerotic plague extension was higher than observed at CT approximately at 10 mm. Conclusion: We can refer critical stenosis, near-occlusion and local occlusion to critical atherosclerotic ICA changes. The one should consider CTA limitations in differentiation of upper part of atherosclerotic plague. In majority of cases decrease in ICA diameter was associated with severe atherosclerotic involvement and not with congenital condition of the circle of Wills. CTA is necessary for preoperative assessment of carotid occlusive disease, especially in critical ICA changes.Figure 2CTA of critical stenosis (a), near-occlusion (b), local occlusion (c) of ICA.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Disclosure: Nothing to disclose

Unilateral blurred vision due to internal carotid artery occlusive disease

Unilateral blurred vision due to internal carotid artery occlusive disease

Effect sizes of BOLD CVR, resting-state signal fluctuations and time delay measures for the assessment of hemodynamic impairment in carotid occlusion patients

Background and purposeThe BOLD signal amplitude as a response to a hypercapnia stimulus is commonly used to assess cerebrovascular reserve. Despite recent advances, the implementation remains cumbersome and alternative ways to assess hemodynamic impairment are desirable. Resting-state BOLD signal fluctuations (rsBOLD) have been proposed however data on its sensitivity and dependence on baseline venous cerebral blood volume (vCBV) is limited. The primary aim of this study was to compare the effect sizes of resting-state and hypercapnia induced BOLD signal changes in the detection of hemodynamic impairment. The second aim of the study was to assess the dependence of BOLD signal variability on vCBV. Materials and methodsFifteen patients with internal carotid artery occlusive disease and 15 matched healthy controls were included in this study. The BOLD signal was derived from a dual-echo gradient-echo echo-planar sequence during hypercapnia (HC) and hyperoxia (HO) gas modulations. BOLD (fractional) amplitude of low frequency fluctuations ((f)ALFF) was compared to HC-BOLD, BOLD response delays derived from time delay analysis and ΔBOLD in response to progressively increasing HC. Effect sizes (i.e. the standard mean difference between patients and controls) were calculated. HO-BOLD was used to estimate vCBV, and its contribution to the variability in rsBOLD signal was evaluated. ResultsThe effect sizes of ALFF and fALFF (0.61 and 0.72) were lower than the effect sizes related to hypercapnia-based hemodynamic assessment analysis; 1.62, 1.56 and 0.90 for HC-BOLD, BOLD response delays and ΔBOLD in response to progressively increasing HC. A moderate relation was found between (f)ALFF and HC-BOLD in controls (R2 of 0.61 and 0.42), but this relation decreased in patients (R2 of 0.33 and 0.15). (f)ALFF did not differ between patients and controls whereas HC-BOLD did (p < 0.005). The ΔBOLD response to progressively increasing HC was significantly different in between patients and controls for ΔEtCO2 values ≥ 2 mmHg (at +2 mmHg F(1, 18) = 5.85, p = 0.026). Up to 31% and 53% of the variance in the ALFF and HC-BOLD spatial distribution could be explained by HO-BOLD. ConclusionALFF and fALFF demonstrated a moderate effect size to detect hemodynamic impairment whereas the effect size was large for methods employing a hypercapnia-based vascular stress stimulus. Based on our analysis of BOLD signal change as a response to a progressively increasing hypercapnia stimulus we can argue that a hypercapnia stimulus of at least 2 mmHg above baseline EtCO2 is necessary to evaluate hemodynamic impairment. We also demonstrated that a substantial amount of information imbedded in the rsBOLD and HC-BOLD was explained by HO-BOLD. HO-BOLD can serve as a proxy for vCBV and this thus indicates that one should be careful when adopting these techniques in disease cases with compromised CBV.

Abstract WP28: Safety and Feasibility of Angioplasty and Stenting in Symptomatic Internal Carotid Artery Occlusive Disease

Introduction: Symptomatic internal carotid artery occlusion (ICAO) can lead to subsequent neurologic decline, recurrent stroke, and mortality. We sought to evaluate safety and feasibility of endovascular revascularization for ICAO without tandem intracranial large vessel occlusion (LVO). Methods: This is a retrospective cohort analysis of all patients presenting to a single academic center with ischemic stroke and ipsilateral, cervical ICAO from November 2003 through April 2016. Patients were excluded if pre-procedural angiography demonstrated tandem LVO or if patients were known to have chronic ICAO. Study endpoints included discharge neurologic exam, post-procedural infarct burden, 3-month functional outcomes, and treatment durability. Results: A total of 107 patients with symptomatic, angiographically confirmed cervical ICAO without tandem LVO were identified. Median admission NIHSS was 8 (IQR 11). Baseline radiographic stroke severity was assessed by ASPECT score (median 9; IQR 2), perfusion mismatch (present in 93%), and clinical-diffusion mismatch (42%). Median time from symptom onset to treatment was 25 hours (IQR 61). Successful revascularization was achieved in 92% of patients. At discharge, 83% had stable or improved NIHSS, while at 3-months 65% achieved functional independence (mRS ≤2). The most common complication was distal embolization (22%) of which 16% required intra-arterial treatment. Rate of significant restenosis (≥70%) was 15% at 1-year. Conclusions: Stenting in selected patients at risk of neurological deterioration due to symptomatic ICAO can be performed with high rates of technical success and good clinical outcomes. Because of significant peri-procedural risks and high rates of restenosis, randomized studies are necessary to understand the benefit of this approach.

Intermittent mydriasis associated with carotid vascular occlusion

PurposeTo describe two cases of stereotyped, intermittent, neurologically isolated, unilateral mydriasis in patients with a history of acquired internal carotid artery (ICA) occlusive disease on the ipsilateral side.PatientsTwo patients with intermittent mydriasis.MethodsCase Series.ResultsCase one: A 78-year-old man experienced 10 episodes of intermittent, unilateral, and painless mydriasis in the left eye and had 100% occlusion of the left ICA artery due to atherosclerotic disease. Case two: A 26-year-old woman with history of migraine developed new painless, intermittent episodes of unilateral mydriasis after sustaining chest trauma and was diagnosed with subsequent dissection and 65% occlusion of the ipsilateral ICA. Neither patient developed permanent anisocoria.ConclusionBenign episodic unilateral mydriasis (BEUM) typically presents in young women with a history of migraine. To our knowledge, these are the first cases of episodic, unilateral, neurologically isolated mydriasis associated with occlusive disease of the ICA in the English language ophthalmic literature. We hypothesize that transient dysfunction of the autonomic nervous system related to the ICA disease may account for the intermittent mydriatic episodes in these patients and we recommend consideration for imaging of the ICA in patients with atypical features for BEUM (for example, old age or males, non-isolated mydriasis, or recent trauma).

Optimal Brain 99mTc-Ethyl Cysteinate Dimer SPECT Imaging and Analysis to Detect Misery Perfusion on 15O PET Imaging in Patients With Chronic Occlusive Disease of Unilateral Major Cerebral Artery.

PurposeMisery perfusion is defined as marginally sufficient cerebral blood supply relative to cerebral metabolic demand. The aim of the present study was to determine the optimal brain 99mTc–ethyl cysteinate dimer (ECD) SPECT imaging and analysis to detect misery perfusion on 15O PET imaging in patients with chronic occlusive disease of unilateral internal carotid or middle cerebral artery (MCA).MethodsFor 97 patients, cerebral blood flow, cerebral metabolic rate of oxygen, and oxygen extraction fraction were measured using 15O PET; 99mTc-ECD SPECT was performed using dynamic scanning with a scan duration of 10 minutes each for 50 minutes after tracer administration. A region of interest was placed in the bilateral MCA territories and in the bilateral cerebellar hemispheres in all standardized images using a 3-dimensional stereotaxic region-of-interest template and affected-to-contralateral asymmetry ratio in the MCA territory (ARMCA) and contralateral-to-affected asymmetry ratio in the cerebellar hemisphere (ARcbl) were calculated.ResultsThe ARMCA or ARcbl on 99mTc-ECD SPECT with a scan time of 20 to 30 minutes after tracer administration (ARMCA20–30 or ARcbl20–30) was correlated with ARMCA on PET cerebral blood flow (r = 0.654) or ARMCA on PET cerebral metabolic rate of oxygen (r = 0.576), respectively, more strongly than with other scan times. The area under the receiver operating characteristic curve for detecting abnormally elevated ARMCA on PET oxygen extraction fraction was significantly greater for ARcbl20–30/ARMCA20–30 (0.947) than for ARMCA20–30 alone (0.780) (difference between areas, 0.167; P = 0.0001) on 99mTc-ECD SPECT.ConclusionsCombination of asymmetries in the cerebellar and cerebral hemispheres on 99mTc-ECD SPECT in a scan time of 20 to 30 minutes after tracer administration optimally detects misery perfusion in unilateral internal carotid artery or MCA occlusive disease.

Long-term Prognosis after Extracranial-intracranial Bypass Surgery for Symptomatic Cerebrovascular Occlusive Disease.

Prognosis after extracranial-intracranial (EC-IC) bypass surgery has only been studied for a few years and the benefits of this procedure are still controversial. In this single-center retrospective study, we examined the long-term prognosis of patients who underwent EC-IC bypass surgery. Subjects were patients with symptomatic internal carotid artery or intracranial lesion occlusive disease who underwent EC-IC bypass surgery between 1991 and 2003. Of these, long-term prognosis was examined in 57 patients (39 male, 18 female; mean age, 61.8 years) who showed good surgical outcomes 30 days after bypass surgery, measured as a 0-2 on the modified Rankin Scale (mRS). They were divided into 2 groups (survivors and non-survivors) and were analyzed to identify factors effecting long-term survival after bypass surgery. Sixteen patients (28%), whose mean follow-up period (survival time) was 8.3±3.8 years, died after the bypass surgery. The average follow-up period for the survivors was 12.0±1.1 years, which was significantly longer than that for the non-survivors (P<0.0001). At surgery, the non-survivors (mean age 71.5 years) were significantly older than the survivors (P=0.0012). Pneumonia and other respiratory diseases were a frequent cause of death (31.2%), but death by cerebrovascular disease also occurred (12.5%). The rate of recurrent ischemic stroke was 28%, with no significant difference between groups (survivors vs. non-survivors: 31.2% vs. 26.1%, P= 0.82). In the absence of perioperative complications, the long-term prognosis of patients who underwent EC-IC bypass surgery was very good.

MEG Frequency Analysis Depicts the Impaired Neurophysiological Condition of Ischemic Brain.

PurposeQuantitative imaging of neuromagnetic fields based on automated region of interest (ROI) setting was analyzed to determine the characteristics of cerebral neural activity in ischemic areas.MethodsMagnetoencephalography (MEG) was used to evaluate spontaneous neuromagnetic fields in the ischemic areas of 37 patients with unilateral internal carotid artery (ICA) occlusive disease. Voxel-based time-averaged intensity of slow waves was obtained in two frequency bands (0.3–4 Hz and 4–8 Hz) using standardized low-resolution brain electromagnetic tomography (sLORETA) modified for a quantifiable method (sLORETA-qm). ROIs were automatically applied to the anterior cerebral artery (ACA), anterior middle cerebral artery (MCAa), posterior middle cerebral artery (MCAp), and posterior cerebral artery (PCA) using statistical parametric mapping (SPM). Positron emission tomography with 15O-gas inhalation (15O-PET) was also performed to evaluate cerebral blood flow (CBF) and oxygen extraction fraction (OEF). Statistical analyses were performed using laterality index of MEG and 15O-PET in each ROI with respect to distribution and intensity.ResultsMEG revealed statistically significant laterality in affected MCA regions, including 4–8 Hz waves in MCAa, and 0.3–4 Hz and 4–8 Hz waves in MCAp (95% confidence interval: 0.020–0.190, 0.030–0.207, and 0.034–0.213), respectively. We found that 0.3–4 Hz waves in MCAp were highly correlated with CBF in MCAa and MCAp (r = 0.74, r = 0.68, respectively), whereas 4–8 Hz waves were moderately correlated with CBF in both the MCAa and MCAp (r = 0.60, r = 0.63, respectively). We also found that 4–8 Hz waves in MCAp were statistically significant for misery perfusion identified on 15O-PET (p<0.05).ConclusionsQuantitatively imaged spontaneous neuromagnetic fields using the automated ROI setting enabled clear depiction of cerebral ischemic areas. Frequency analysis may reveal unique neural activity that is distributed in the impaired vascular metabolic territory, in which the cerebral infarction has not yet been completed.

Superficial temporal artery to middle cerebral artery bypass with interposed saphenous vein graft in patients with atherosclerotic internal carotid artery occlusive disease and impaired cerebral hemodynamics.

The aim of this study was to evaluate the efficacy of interposed saphenous vein graft (SVG) usage during extracranial-intracranial (EC-IC) bypass surgery in patients with cerebral ischemia and appropriate donor artery absence. Since October 2010 till January 2014, 62 EC-IC bypass surgeries were applied in 60 patients. In nineteen patients SVG was used to create low-flow bypasses between superficial temporal artery trunk and cortical segment of middle cerebral artery. SVG was used due to inappropriate diameter of scalp artery in 12 cases, inadequate flow in intended donor artery in 5 patients and in 2 cases for other reasons. Indications for revascularization were based on clinical symptoms of cerebral hemodynamics impairment, confirmed with transcranial duplex ultrasonography (DUS) and brain perfusion computed tomography (CT). Early bypass patency was confirmed with DUS up to 9 postoperative day in 16 patients. In 3 (15.8%) patients blood flow was not visualized. Bypass patency in these patients was confirmed with repeated DUS up to 42 months period. At mean clinical follow-up of 22.3 months 14 patients (73.7%) reported an improvement of their condition, 4 patients (21%) didn't observe any changes in well-being and 1 patient (5.3%) got worse. Late bypass patency assessment was available and confirmed in 16 patients at mean follow-up of 15.6 months postoperation. Repeated brain perfusion CT was performed in 10 patients at mean follow-up of 5.2 months. Average growth of regional cerebral blood flow was 24.1%. The use of interposed SVG bypass for EC-IC revascularization is an effective method, that could be applied in patients with cerebral ischemia caused by internal carotid artery occlusive disease and absence of appropriate donor artery.

Heads Up! A Novel Provocative Maneuver to Guide Acute Ischemic Stroke Management

Background: A common dilemma in acute ischemic stroke management is whether to pursue recanalization therapy in patients with large vessel occlusions but minimal neurologic deficits. We describe and report preliminary experience with a provocative maneuver, i.e. 90-degree elevation of the head of bed for 30 min, which stresses collaterals and facilitates decision-making. Methods: A prospective cohort study of <7.5 h of acute anterior circulation territory ischemia patients with minimal deficits despite middle cerebral artery (MCA) or internal carotid artery (ICA) occlusive disease. Results: Five patients met the study entry criteria. Their mean age was 78.4 years (range 65-93). All presented with substantial deficits (median NIHSS score 11, range 5-22), but improved while in supine position during initial imaging to normal or near-normal (NIHSS score 0-2). MRA showed persistent M1 MCA occlusions in 4, critical ICA stenosis or occlusion in 1, and substantial perfusion-diffusion mismatch in all. To evaluate the potential for eventual collateral failure, patients were placed in a head of bed upright posture. Mean arterial pressure and heart rate were unchanged. Two showed no neurologic worsening and were treated with supportive care with excellent final outcome. Three showed worsening, including recurrent hemiparesis and aphasia at the 6th, recurrent aphasia at the 23rd, and recurrent hemineglect at the 15th upright minute. These 3 underwent endovascular recanalization therapies with successful reperfusion and excellent final outcome. Conclusion: The ‘Heads Up' test may be a useful, simple maneuver to assess the risk of collateral failure and guide the decision to pursue recanalization therapy in acute cerebral ischemia patients with minimal deficits despite persisting large cerebral artery occlusion.

Progressive Cortical Neuronal Damage and Chronic Hemodynamic Impairment in Atherosclerotic Major Cerebral Artery Disease.

Cross-sectional studies suggest that chronic hemodynamic impairment may cause selective cortical neuronal damage in patients with atherosclerotic internal carotid artery or middle cerebral artery occlusive disease. The purpose of this longitudinal study was to determine whether the progression of cortical neuronal damage, evaluated as a decrease in central benzodiazepine receptors (BZRs), is associated with hemodynamic impairment at baseline or hemodynamic deterioration during follow-up. We evaluated the distribution of BZRs twice using positron emission tomography and (11)C-flumazenil over time in 80 medically treated patients with atherosclerotic internal carotid artery or middle cerebral artery occlusive disease that had no ischemic episodes during follow-up. Using 3D stereotactic surface projections, we quantified abnormal decreases in the BZRs in the cerebral cortex within the middle cerebral artery distribution and correlated changes in the BZR index with the mean hemispheric values of hemodynamic parameters obtained from (15)O gas positron emission tomography. In the hemisphere affected by arterial disease, the BZR index in 40 patients (50%) was increased during follow-up (mean 26±20 months). In multivariable logistic regression analyses, increases in the BZR index were associated with the decreased cerebral blood flow at baseline and an increased oxygen extraction fraction during follow-up. Increases in the oxygen extraction fraction during follow-up were associated with a lack of statin use. In patients with atherosclerotic internal carotid artery or middle cerebral artery disease, the progression of cortical neuronal damage was associated with hemodynamic impairment at baseline and hemodynamic deterioration during follow-up. Statin use may be beneficial against hemodynamic deterioration and therefore neuroprotective.

慢性期脳虚血性病変に対して安全確実にSTA-MCAバイパス術を完遂するための外科的治療戦略

Extracranial-intracranial (EC-IC) bypass is one of the most fundamental techniques for cerebrovascular surgery. We describe our surgical results and strategy for performing the EC-IC bypass safely and precisely in patients with chronic stage ischemia. Surgical indications were decided for symptomatic internal carotid or middle cerebral artery occlusive disease with misery perfusion detected using quantitative single-photon emission computed tomography. Antiplatelet medications were continued, and intravenous hyperosmotic colloid infusion was started 1 week before operation. Target recipient M4 arteries were superimposed on the superficial temporal artery and cranial bone. Preparation of the superficial temporal artery was performed by using an ultrasound instrument (Harmonic Scalpel®). The craniotomy site was located under the supratemporal line. Various anastomotic techniques were adopted, including continuous, running, and intermittent suturing methods. The second target recipient artery was confirmed using intra-arterial indocyanine green videoangiography. Hyperbaric oxygen therapy was performed for wound problems. Forty patients (43 sides) underwent EC-IC bypass between September 2010 and March 2015 (mean age, 64.5 years; 28 men and 12 women; double bypass in 35 patients and single bypass in eight). Postoperative complications were chronic subdural hematomas and skin problems in five patients each. None of the patients had permanent deficit. Well-drained operative field and steady hand movements are necessary to perform safe and secure bypass procedures. The various technical tips and surgical strategies that we have suggested can contribute to improving surgical results.

A Retrospective 10-Year, Single-Institution Study of Carotid Endarterectomy with a Focus on Elderly Patients.

Background and PurposeThis study evaluated the outcome following surgery for carotid artery stenosis in a single institution during a 10-year period and the relevance of aging to access to surgery.MethodsBetween January 2001 and December 2010, 649 carotid endarterectomies (CEAs) were performed in 596 patients for internal carotid artery occlusive disease at our institution; 596 patients received unilateral CEAs and 53 patients received bilateral CEAs. Data regarding patient characteristics, comorbidities, stroke, mortality, restenosis, and other surgical complications were obtained from a review of medical records. Since elderly and high-risk patients comprise a significant proportion of the patient group undergoing CEAs, differences in comorbidity and mortality were evaluated according to age when the patients were divided into three age groups: <70 years, 70-79 years, and ≥80 years.ResultsThe mean age of the included patients was 67.5 years, and 88% were men. Symptomatic carotid stenosis was observed in 65.7% of patients. The rate of perioperative stroke and death (within 30 days of the procedure) was 1.84%. The overall mortality rate was higher among patients in the 70-79 years and >80 years age groups than among those in the <70 years age group, but there was no significant difference in stroke-related mortality among these three groups.ConclusionsCEA over a 10-year period has yielded acceptable outcomes in terms of stroke and mortality. Therefore, since CEA is a safe and effective strategy, it can be performed in elderly patients with acceptable life expectancy.

Evidence for Cerebral Hemodynamic Measurement-based Therapy in Symptomatic Major Cerebral Artery Disease.

In patients with atherosclerotic internal carotid artery or middle cerebral artery occlusive disease, chronic reduction in cerebral perfusion pressure (chronic hemodynamic compromise) increases the risk of ischemic stroke and can be detected by directly measuring hemodynamic parameters. However, strategies for selecting treatments based on hemodynamic measurements have not been clearly established. Bypass surgery has been proven to improve hemodynamic compromise. However, the benefit of bypass surgery for reducing the stroke risk in patients with hemodynamic compromise is controversial. The results of the two randomized controlled trials were inconsistent. Hypertension is a major risk factor for stroke, and antihypertensive therapy provides general benefit to patients with symptomatic atherosclerotic major cerebral artery disease. However, the benefit of strict control of blood pressure for reducing the stroke risk in patients with hemodynamic compromise is a matter of debate. The results of the two observational studies were different. We must establish strategies for selecting treatments based on hemodynamic measurements in atherosclerotic major cerebral artery disease.

Detection of misery perfusion in the cerebral hemisphere with chronic unilateral major cerebral artery steno-occlusive disease using crossed cerebellar hypoperfusion: comparison of brain SPECT and PET imaging

PurposeIn patients with unilateral internal carotid or middle cerebral artery (ICA or MCA) occlusive disease, the degree of crossed cerebellar hypoperfusion that is evident within a few months after the onset of stroke may reflect cerebral metabolic rate of oxygen in the affected cerebral hemisphere relative to that in the contralateral cerebral hemisphere. The aim of the present study was to determine whether the ratio of blood flow asymmetry in the cerebellar hemisphere to blood flow asymmetry in the cerebral hemisphere on positron emission tomography (PET) and single photon emission computed tomography (SPECT) correlates with oxygen extraction fraction (OEF) asymmetry in the cerebral hemisphere on PET in patients with chronic unilateral ICA or MCA occlusive disease and whether this blood flow ratio on SPECT detects misery perfusion in the affected cerebral hemisphere in such patients.MethodsBrain blood flow and OEF were assessed using 15O-PET and N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) SPECT, respectively. All images were anatomically standardized using SPM2. A region of interest (ROI) was automatically placed in the bilateral MCA territories and in the bilateral cerebellar hemispheres using a three-dimensional stereotaxic ROI template, and affected-to-contralateral asymmetry in the MCA territory or contralateral-to-affected asymmetry in the cerebellar hemisphere was calculated. Sixty-three patients with reduced blood flow in the affected cerebral hemisphere on 123I-IMP SPECT were enrolled in this study.ResultsA significant correlation was observed between MCA ROI asymmetry of PET OEF and the ratio of cerebellar hemisphere asymmetry of blood flow to MCA ROI asymmetry of blood flow on PET (r = 0.381, p = 0.0019) or SPECT (r = 0.459, p = 0.0001). The correlation coefficient was higher when reanalyzed in a subgroup of 43 patients undergoing a PET study within 3 months after the last ischemic event (r = 0.541, p = 0.0001 for PET; r = 0.609, p < 0.0001 for SPECT). The blood flow ratio on brain perfusion SPECT in all patients provided 100 % sensitivity and 58 % specificity, with 43 % positive and 100 % negative predictive values for detecting abnormally elevated MCA ROI asymmetry of PET OEF.ConclusionThe ratio of blood flow asymmetry in the cerebellar hemisphere to blood flow asymmetry in the cerebral hemisphere on PET and SPECT correlates with PET OEF asymmetry in the cerebral hemisphere, and this blood flow ratio on SPECT detects misery perfusion in the affected cerebral hemisphere.

Mapping white matter diffusion and cerebrovascular reactivity in carotid occlusive disease

To characterize the relationship between cerebrovascular reactivity (CVR) and white matter (WM) diffusion in patients with internal carotid artery (ICA) occlusive disease. In this exploratory observational study, 41 patients with severe stenosis or occlusion of the extracranial ICA and 12 healthy control subjects underwent CVR mapping using the fMRI response to hypercapnia. Conventional anatomic and diffusion-weighted MRI sequences were used to calculate maps of the apparent diffusion coefficient (ADC) and to exclude areas of previous ischemic injury. In all subjects, ADC was compared between WM with positive and negative CVR. In 27 patients with unilateral ICA involvement, ADC and CVR were compared between ipsilateral and contralateral WM while covarying for relevant clinical risk factors. In patients with bilateral disease and in the ipsilateral hemisphere of patients with unilateral disease, negative CVR was associated with increased WM ADC (p < 0.01 and p < 0.005, respectively). In patients with unilateral disease, the ipsilateral CVR deficit was correlated with the degree of hemispheric WM ADC elevation (p < 0.005). ADC elevation remained significant after correction for potential confounding risk factors. CVR impairment is associated with ADC elevation in normal-appearing WM of patients with severe stenosis or occlusion of the extracranial ICA. This finding is consistent with the presence of early, low-grade ischemic injury.