Thrombus formation during cerebrovascular catheterization in heparin-induced thrombocytopenia.
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Aged↗
Biomedical subjects
K Minematsu
Publications and source records attributed to K Minematsu.
Glucose utilization in the inferior cerebellar vermis and ocular myoclonus.
In a patient with symptomatic ocular myoclonus, the authors observed the regional cerebral metabolic rate of glucose use (rCMRGlu) before and after successful treatment with clonazepam. Even after the symptoms resolved, the rCMRGlu in the hypertrophic olive increased persistently, whereas that in the inferior cerebellar vermis contralateral to the hypertrophic olive decreased. The inferior cerebellar vermis, belonging to the vestibulocerebellar system, may be associated with the generation of symptomatic ocular myoclonus.
Aged, 80 and over↗
Intermittent oro-esophageal tube feeding in acute stroke patients -- a pilot study.
OBJECTIVE: Acute stroke patients with dysphagia are usually fed by nasogastric tube. However, this method sometimes causes pneumonia or diarrhea. We investigated the use of a new feeding procedure called intermittent oro-esophageal (IOE) tube feeding in acute stroke patients with severe dysphagia. MATERIALS AND METHODS: The IOE method was used in 13 acute stroke patients (68 +/- 14 years old; 12 had a brainstem infarction), who were alert, but had severe dysphagia and a weak pharyngeal reflex. IOE tube feeding was carried out as follows. A feeding tube was passed orally into the lower portion of the esophagus, food supplements were administered through the tube at a rate of approximately 50 ml/min, and the tube was removed after finishing the supplement infusion. RESULTS: We found that the IOE method had the following advantages: (i) IOE feeding took approximately 15 min; (ii) potentially reduced a risk of complications such as pneumonia and diarrhea; and (iii) oral tube insertion stimulated the oral cavity and pharynx, which may improve the swallowing function. However, the IOE feeding method should not be used in patients who: (i) could not understand the IOE procedure; (ii) had an esophageal hiatal hernia or incomplete peristalsis of the esophagus, as such patients are at risk of having the supplement reflux into the oral cavity. CONCLUSION: The IOE feeding method may be one of the alternatives to continuous nasogastric tube feeding in acute stroke patients with severe dysphagia, who are alert.
Acute Disease↗
Antiplatelet therapy contributes to acute deterioration of intracerebral hemorrhage.
OBJECTIVE: The purpose of this study was to examine the effect of antiplatelet therapy on the initial severity and the acute outcome of intracerebral hemorrhage (ICH). METHODS: The authors reviewed records of 251 consecutive patients hospitalized in their cerebrovascular center within 24 hours after onset of ICH. RESULTS: Fifty-seven patients (23%) had development of ICH during oral antiplatelet therapy. The major indication for antiplatelet therapy was the prevention of stroke recurrence (63%). As compared with patients without antiplatelet therapy, those who received antiplatelet therapy more frequently were aged 70 years or older (60% vs 35%; p < 0.001), had previous symptomatic ischemic stroke (54% vs 7%; p < 0.0001), had diabetes mellitus (26% vs 15%; p < 0.05), and had heart disease (32% vs 8%; p < 0.0001). Antiplatelet therapy was predictive of an increase in the hematoma volume by more than 40% on the second hospital day (hematoma enlargement, odds ratio [OR] 7.67, 95% CI 1.62 to 36.4) and the need for emergent surgical evacuation of the hematoma (OR 3.10, 95% CI 1.18 to 8.15). Antiplatelet therapy was an independent predictor for the occurrence of any of hematoma enlargement, emergent death, or evacuation surgery, which suggests that clinical deterioration occurs into the second hospital day (OR 7.45, 95% CI 2.46 to 22.5). CONCLUSIONS: Antiplatelet therapy seems to contribute to the acute clinical deterioration of intracerebral hemorrhage.
Administration, Oral↗
Atrial fibrillation as a predictive factor for severe stroke and early death in 15,831 patients with acute ischaemic stroke.
BACKGROUND: Atrial fibrillation (AF) is a common arrhythmia and a major risk factor for stroke. AIMS: To assess whether AF in patients with acute ischaemic stroke is associated with severe stroke and early death. MATERIALS/METHODS: Patients with acute ischaemic stroke (15,831) who were registered in the Japan Multicenter Stroke Investigators' Collaboration registry were analysed. The AF group comprised 3335 (21.1%) patients (median age, 75 years) and the non-AF group comprised 12,496 (78.9%) patients (median age, 70 years). The association between AF and severe stroke and early death was investigated by means of multivariate logistic regression analysis. RESULTS: The admission National Institutes of Health Stroke Scale (NIHSS) score of the AF group was higher than that of the non-AF group (median, 12 v 5; p < 0.0001). Multivariate logistic regression analyses found that female sex, advanced age, AF, and a history of stroke were independent factors associated with severe stroke (NIHSS score, > or = 11). The mortality rate within 28 days after admission was 11.3% in the AF group and 3.4% in the non-AF group (p < 0.0001). Multivariate logistic regression analyses identified older age, AF, and NIHSS score at admission as independent factors associated with early death. CONCLUSION: AF was a predictive factor for severe stroke and early death in acute ischaemic stroke. Careful cardiac evaluation and appropriate treatment are needed to improve outcome in patients with acute stroke and AF.
Acute Disease↗
A case of frequently recurring amaurosis fugax with atherothrombotic ophthalmic artery occlusion.
A 49-year-old woman with diabetes mellitus and hyperlipidemia experienced frequent transient monocular blindness in the right eye during a 3-week period. Examination revealed atherothrombotic occlusion of the right ophthalmic artery (OA) without embolic sources. After treatment with aspirin, attacks resolved completely. Her symptoms were attributed to microembolism from the occluded OA.
Amaurosis Fugax↗
Isolated pulmonary arteriovenous fistula without Rendu-Osler-Weber disease as a cause of cryptogenic stroke.
There has been uncertainty as to whether a right to left shunt through an isolated pulmonary arteriovenous fistula (P-AVF) without Rendu-Osler-Weber (ROW) disease can cause paradoxical brain embolism. A population of 747 acute ischaemic stroke patients was examined to determine the frequency and clinical characteristics of those patients who had an isolated P-AVF. The presence of a P-AVF was determined as follows. On patients with a stroke of undetermined cause, both transoesophageal echocardiography and transcranial Doppler with saline contrast medium was performed to detect a right to left shunt. If a P-AVF was then suspected, selective pulmonary angiography and enhanced chest CT was performed to confirm the presence of the P-AVF. Four patients (0.5%) were diagnosed as having a stroke associated with an isolated P-AVF. All the patients were middle-aged women (mean age 61 years). In all these patients, the P-AVF could not have been suspected on physical findings or chest x ray. The P-AVF was always single and located in the lower lobe. All the patients had asymptomatic deep venous thrombosis, and three patients developed pulmonary embolism. As D-dimer and thrombin-antithrombin complex were elevated in all patients, this indicated an activation of both fibrinolytic and thrombin activity. Our results show that an isolated P-AVF without ROW disease can cause paradoxical brain embolism. Thus, the existence of an isolated P-AVF as a right to left shunt in patients with a stroke of unknown origin should not be overlooked, even if a P-AVF is not suggested by the initial physical findings or chest x ray.
Aged↗
Population-based distribution of plasminogen activity and estimated prevalence and relevance to thrombotic diseases of plasminogen deficiency in the Japanese: the Suita Study.
Reduced plasminogen activity with a normal level of antigen is commonly observed in Japanese individuals. The first reported patient with plasminogen deficiency was accompanied with deep vein thrombosis. The present study examines whether heterozygous or homozygous deficiency of plasminogen is a risk factor for thrombotic disease. This study measures the plasminogen activity of 4517 individuals in the general population, determines the cut-off to define plasminogen deficiency, and identifies plasminogen deficiencies in the control groups and thrombotic disease groups. In another study, we examined the phenotypes of consecutive patients with homozygous plasminogen deficiency detected in our hospital. We found 173 and two of 4517 individuals to have heterozygous and homozygous deficiency with normal plasminogen antigen level, respectively, and 19 to have heterozygous deficiency with reduced antigen levels. The incidence of plasminogen deficiency in an age- and sex-matched control group (13/324, 4.01% for deep vein thrombosis or 13/330, 3.94% for stroke) selected from the 4517 individuals was not significantly different from those in patients with deep vein thrombosis (3/108, 2.78%) or cardioembolic stroke (6/110, 5.55%). Among 19 patients with homozygous plasminogen deficiency showing about 10% plasminogen activity, none had deep vein thrombosis. These findings indicate that neither heterozygous nor homozygous plasminogen deficiency constitutes a significant risk factor for thrombotic disease.
Aged↗
Effect of prothrombin complex concentrate on INR and blood coagulation system in emergency patients treated with warfarin overdose.
We investigated the effect of prothrombin complex concentrate (PCC) on the international normalized ratio (INR) and blood coagulation system in two emergent patients treated with warfarin for secondary prevention of cardioembolic stroke due to nonvalvular atrial fibrillation. An 80-year-old woman developed massive subcutaneous hemorrhage and swelling on her right upper extremity with weak pulsation of the right radial artery and had an INR above 10. An 83-year-old man had pleural effusion with an INR value of 6.69 and pleural puncture was immediately required. We administered 500 IU of PCC to the two patients (17.2 IU/kg and 12.5 IU/kg) with 10 mg of vitamin K. The INR decreased to 1.12 and 1.85, respectively, with an increase of plasma levels of protein C and coagulant factors IIa, VIIa, IXa, and Xa 10 min after administration. The plasma levels of the thrombin-antithrombin III complex increased (from 4.0 to 12.0 micro g/l and from 0.5 to 28.9 micro g/l, respectively, normal value <3.0), but prothrombin fragment 1+2 increased minimally 10 min after administration (from 0.4 to 1.1 nmol/ml and from 0.4 to 0.7 nmol/ml, respectively, normal value 0.4-1.4 nmol/ml). Plasma levels of D-dimer remained unchanged. The massive subcutaneous hemorrhage in the former patient improved in 14 days. Anticoagulation was restarted in the latter patient after 14 days of PCC administration. There were no embolic episodes during the month after PCC administration. In conclusion, a small amount of PCC may be effective in immediately correcting increased INR levels with increased plasma levels of protein C and coagulant factors IIa, VIIa, IXa, and Xa and may partially activate the coagulation system without any effects on plasma levels of D-dimer.
Aged↗
Experimental thromboembolic stroke in cynomolgus monkey.
To develop an experimental model of thromboembolic stroke without intracranial surgery, an autologous blood clot was delivered to the middle cerebral artery (MCA) via the internal carotid artery in cynomolgus monkeys. Male cynomolgus monkeys, in which a chronic catheter had been earlier implanted in the left internal carotid artery, were used. The clot was flushed into the internal carotid artery under sevofluorane anesthesia. A neurologic deficit score was assigned after MCA embolization. After 24 h, cerebral infarct size and location were determined by the TTC staining method. Cerebral blood flow (CBF) was measured prior to and after MCA embolization, using positron emission tomography (PET). After embolization, long-lasting and profound extensor hypotonia of the contralateral upper and lower limbs, and mild to severe incoordination were observed. Contralateral hemiplegia was observed over the following 24 h. In gross morphologic observation of the brain, the lesions involved mostly the caudate nucleus, putamen, globus pallidus and insular cortex. CBF was maximally reduced in the left MCA territory, but not in the right MCA territory. This model is relevant to thromboembolic stroke in human in neurologic dysfunction and histopathologic brain damage.
Animals↗
Serial changes in cerebral blood flow and flow-metabolism uncoupling in primates with acute thromboembolic stroke.
The authors recently developed a primate thromboembolic stroke model. To characterize the primate model, the authors determined serial changes in cerebral blood flow (CBF) and the relation between CBF and cerebral metabolic rate of glucose (CMRglc) using high-resolution positron emission tomography. Thromboembolic stroke was produced in male cynomolgus monkeys (n = 4). Acute obstruction of the left middle cerebral artery was achieved by injecting an autologous blood clot into the left internal carotid artery. Cerebral blood flow was measured with [15O]H2O before and 1, 2, 4, 6, and 24 hours after embolization. CMRglc was measured with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) 24 hours after embolization. Lesion size and location 24 hours after embolization was determined by the 2,3,5-triphenyltetrazolium chloride (TTC) staining method. The results are summarized as follows: (1) 1 hour after embolization, CBF in the temporal cortex and the basal ganglia decreased to < 40% of the contralateral values. In these regions, regarded as an ischemic core, CBF decreased further with time and CMRglc at 24 hours also decreased. Infarcted lesions as indicated by being unstained with TTC were consistently observed in these regions. (2) In the parietal cortex and several regions surrounding the ischemic core, CBF was > 40% of the contralateral values 1 hour after embolization and recovered gradually with time (ischemic penumbra). In these regions, CMRglc at 24 hours increased compared with that in the contralateral regions, indicating an uncoupling of CBF and CMRglc. No obvious TTC-unstained lesions were detected in these regions. The authors demonstrated a gradual recovery of reduced CBF, an elevated CMRglc and a CBF-CMRglc uncoupling in the penumbra regions of the primate model. Positron emission tomography investigations using this model will provide better understanding of the pathophysiology of thromboembolic stroke in humans.
Acute Disease↗
Hypertension and neurovascular compression of the left lateral medulla oblongata in ischemic stroke.
Hypertension is a major risk factor for stroke. Neurovascular compression (NC) of the left ventrolateral medulla oblongata may cause arterial hypertension. We evaluated the relationship between the two ischemic stroke patients. We classified 69 patients under 50 years old (49 men and 20 women, aged 43.6 +/- 7.3 years) based on magnetic resonance imaging findings as follows: NC patients (n = 38; 10 with NC on the right side, 18 with NC on the left side, and 10 with NC on both sides) and non-NC patients (n = 31). We compared the following clinical characteristics between the two groups: (1) risk factors for stroke, including hypertension, diabetes mellitus, hypercholesterolemia, and smoking and (2) stroke subtype. Hypertension was more frequent in the NC group than in the non-NC group (58 vs. 19%, p = 0.001). Hypertension was more frequent in patients with left-side NC than in those with right-side NC (78 vs. 20%, p = 0.005). No other differences were observed between the two groups. Twelve patients presented with atherothrombotic stroke, 16 with cardioembolic stroke, 24 with lacunar stroke and 17 with stroke of miscellaneous etiology. NC was significantly more common in patients with lacunar stroke as compared with those affected by other stroke subtypes (p = 0.015). We found a significant relationship between hypertension and NC of the ventrolateral medulla oblongata on the left side in ischemic stroke patients younger than 50 years of age. Some patients with lacunar stroke may have hyptertension related to NC.
Adolescent↗
Blood flow in the left atrial appendage and embolic stroke in nonvalvular atrial fibrillation.
It is unclear if low flow velocity in the left atrial appendage (LAA) is a predisposing factor to stroke in patients with nonvalvular atrial fibrillation (NVAF). We investigated flow velocity in the LAA in NVAF patients in relation to a past history of stroke and other potential embolic sources. We measured and analyzed peak flow velocities into (FV-in) and out of (FV-out) the LAA in a middle portion of the LAA in 35 NVAF patients by transesophageal echocardiography (TEE). We divided the NVAF patients into 3 groups: the Eaf group had a history of embolic stroke without any other potential embolic sources; the Emulti group had other potential embolic sources, and the control group had no embolic history. FV-in and FV-out in the Eaf group (12.3 +/- 6.7 and 10.2 +/- 7.3 cm/s) were significantly lower than those in the control group (24.3 +/- 11.3 and 19.9 +/- 8.8 cm/s; multicomparison Scheffé's test, p = 0.0123 and 0.0395, respectively). The Emulti group varied in those values from less than 5 to above 35. Low flow velocity in the LAA seems to be a predisposing factor for stroke in NVAF patients without any other sources of emboli.
Aged↗
Optimal intensity of international normalized ratio in warfarin therapy for secondary prevention of stroke in patients with non-valvular atrial fibrillation.
OBJECTIVE: To determine optimal intensity of international normalized ratio (INR) of warfarin therapy for the prevention of ischemic events in patients with non-valvular atrial fibrillation (NVAF), we evaluated the risk of severe recurrent stroke, systemic embolism and major hemorrhagic complications according to INR and age. METHODS: We carried out the National Cardiovascular Center (NCVC) NVAF Secondary Prevention Study and analyzed data with those of Japanese Nonvaluvular Atrial Fibrillation-embolism Secondary Prevention Cooperative Study to elucidate relationships of major stroke and hemorrhage with INR and age. In both studies, all patients with cardioembolic stroke were given warfarin, monitored with INR every month, and followed up for primary endpoints of stroke and embolism to other parts of the body, and for secondary endpoints of major hemorrhagic complications requiring blood transfusion or hospitalization. We regarded ischemic stroke with NIH stroke scale (NIHSS) score > or = 10 or systemic embolism as a major ischemic event and ischemic stroke with NIHSS score <10 as a minor ischemic event. There were 203 patients enrolled in total (152 men and 51 women). We investigated the relationship of occurrence of the events with INR and age, and calculated the incidence rates of major and minor ischemic events and major hemorrhagic events. RESULTS: During the mean follow-up of 653 days, major ischemic stroke and systemic embolism occurred in only 4 patients with INR <1.6, minor ischemic stroke in 10 patients with INR 1.50-2.66, and major hemorrhage in 9 patients with INR 2.30-3.56. Patients with major ischemic or hemorrhagic events were significantly older than those without any events (75+/-4 years vs. 67+/-7 years, p<0.001 unpaired t test). Incidence rates of any events at INR < or = 1.59, 1.60-1.99, 2.00-2.59 and > or = 2.60 were 8.6%, 3.8%, 4.9%, and 25.7%/year, respectively. CONCLUSIONS: Major ischemic or hemorrhagic events occur often in the elderly NVAF patients, in whom an INR value of between 1.6 and 2.6 seems optimal to prevent such events.
Aged↗
Massive pontine hemorrhagic infarction associated with embolic basilar artery occlusion.
We report here an autopsy case of massive pontine hemorrhagic infarction secondary to embolic basilar artery occlusion. A large embolus appeared to have traversed the vertebral artery into the basilar artery as a result of basilarization of the vertebral artery due to severe stenosis of the contralateral vertebral artery. Extensive ischemia due to embolic occlusion of the entire length of the basilar artery, and migration of the embolus are assumed to have resulted in a massive pontine hemorrhagic infarction.
Aged↗
Diffusion-weighted MR imaging in a case of mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes.
In a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS), both T2- and diffusion-weighted MR imaging revealed lesions as hyperintense areas in the occipital lobes early after strokelike episodes. In these lesions, no significant reduction in apparent diffusion coefficient was noted. Apparent diffusion coefficient mapping may help to differentiate strokelike episodes in MELAS from acute ischemic stroke. The strokelike episodes may be related to vasogenic edema and hyperperfusion, which were suggested by our single-photon emission CT and MR imaging studies.
Adult↗
Diagnosis of internal carotid artery stenosis greater than 70% with power Doppler duplex sonography.
BACKGROUND AND PURPOSE: Duplex sonography is an effective tool for evaluating internal carotid artery (ICA) stenosis, and power Doppler imaging has improved its value in this regard. Our goal was to elucidate which parameters, such as linear stenosis, area stenosis, and peak systolic velocity (PSV), are the most reliable predictors of ICA stenosis greater than 70% using the method proposed by the North American Symptomatic Carotid Endarterectomy Trial (NASCET). METHODS: Duplex sonography with power Doppler imaging and cerebral angiography were performed prospectively in 75 patients (135 vessels). The grade of stenosis on angiograms was calculated by the NASCET method, and linear stenosis, area stenosis, and PSV were measured in the most stenotic part of the ICA. RESULTS: Angiography revealed 20 ICA vessels with stenosis greater than 70%. The correlation between angiographic stenosis and linear stenosis, area stenosis, and PSV was .82, .78, and .84, respectively. A sensitivity-specificity curve analysis determined optimal threshold values of linear stenosis, area stenosis, and PSV as predictors of ICA stenosis greater than 70% as 74.7%, 83.3%, and 200 cm/s, respectively. Calculations of positive and negative predictive values, and accuracy using the optimal threshold values were 90.5%, 99.1%, and 97.8% for linear stenosis; 76.0%, 99.1%, and 94.8% for area stenosis; and 100%, 100%, and 100% for PSV. CONCLUSION: All parameters corresponded relatively well with angiographic stenosis. In particular, PSV greater than 200 cm/s was the most reliable predictor of ICA stenosis greater than 70%. We believe that the combination of parameters plays a crucial role in the accurate assessment of ICA stenosis.
Adult↗
[Acute stroke management in elderly patients. The present and future].
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Acute Disease↗