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Kazunori Toyoda

Publications and source records attributed to Kazunori Toyoda.

At least 19 recordsLinked to original sources
PubMed2023

Association of thyroid peroxidase antibody with the RNF213 p.R4810K variant in ischemic stroke/transient ischemic attack.

BACKGROUND AND AIMS: RNF213 is a susceptibility gene for moyamoya disease and vasospastic angina, with a second hit considered necessary for their development. Elevated thyroid peroxidase antibody (TPO-Ab) levels have been observed in both diseases, suggesting a possible role of TPO-Ab as a second hit for developing RNF213-related vasculopathy. We investigated the association of TPO-Ab levels with RNF213-related ischemic stroke (IS)/transient ischemic attack (TIA), other than moyamoya disease. METHODS: From the National Cerebral and Cardiovascular Center Genome Registry, a multicenter, prospective, observational study, we enrolled patients with IS/TIA who were admitted within 1 week of onset. Patients with IS/TIA due to definite moyamoya disease or hemorrhagic stroke were excluded. Participants underwent genotyping for RNF213 p. R4810K, and baseline characteristics and TPO-Ab levels were compared between RNF213 p. R4810K variant carriers and non-carriers. RESULTS: In total, 2090 IS/TIA patients were analyzed [733 women (35.1%); median age 74 (interquartile range, 63-81) years, baseline NIHSS score 3 (2-6)], and 85 (4.1%) of them carried the variant. Median TPO-Ab levels were significantly higher in variant carriers (8.5 IU/mL vs. 2.1 IU/mL, p&#xa0;< 0.01), who also showed a higher frequency of elevated TPO-Ab levels (>16 IU/mL) (27.1% vs. 4.4%). In the multivariate analysis, presence of the RNF213 p. R4810K variant (adjusted odds ratio, 12.42; 95% confidential interval, 6.23-24.75) was significantly associated with elevated TPO-Ab levels. CONCLUSIONS: Elevated TPO-Ab levels may be significantly associated with presence of the RNF213 p. R4810K variant in IS/TIA patients. Thus, TPO-Ab may inherently modify IS/TIA development in RNF213 p. R4810K variant carriers.

Humans↗
PubMed2006

Antithrombotic therapy and predilection for cerebellar hemorrhage.

BACKGROUND: With the recent increase in the use of antithrombotic therapy, intracerebral hemorrhage (ICH) has been found to be a common complication. We determined whether the use of oral antithrombotic therapy and the patients' preexisting comorbidities were predictive of cerebellar hemorrhage (CH; previously reported to be associated with anticoagulants) as compared to other ICH, and whether antithrombotic therapy affected the clinical severity of CH. METHODS: A study of 327 consecutive patients hospitalized in our institute within 3 days after the onset of ICH, including 38 patients with a CH. RESULTS: CH accounted for 12% of all ICH, 75% of which occurred in patients on warfarin therapy with an international normalized ratio (INR) for prothrombin time >2.5 (p < 0.0001), and 33% of which occurred in patients on ticlopidine therapy (p = 0.017). Warfarin therapy with an INR >2.5 and high blood glucose on admission were independently predictive of CH as compared to other ICH. In addition, previous ischemic stroke (p = 0.002) and heart diseases (p = 0.018) were more prevalent in patients with CH than in those with other ICH. The number of major arteriosclerotic comorbidities and risk factors was also independently predictive of CH risk. CONCLUSIONS: We confirmed that warfarin therapy with an INR >2.5 is associated with CH. Patients with CH frequently had arteriosclerotic comorbidities requiring antithrombotic therapy that can complicate their acute management.

Administration, Oral↗
PubMed2006

Blood pressure changes during the initial week after different subtypes of ischemic stroke.

BACKGROUND AND PURPOSE: The purpose of this study was to clarify the differences in the acute blood pressure course among different ischemic stroke subtypes. METHODS: We divided 588 consecutive patients with acute brain infarction into four clinical subgroups to study the blood pressure levels during the initial 6 hospital days. RESULTS: During the 6 days, systolic blood pressure of lacunar and atherothrombotic patients was higher (P=0.0001) and diastolic blood pressure of lacunar patients was higher (P=0.0371) than of patients with the other subtypes. Preexisting hypertension was associated with elevated acute systolic blood pressure in all patients and in each subtype and with elevated acute diastolic blood pressure in all patients, cardioembolic patients, and patients with stroke of other etiology. After adjustment by preexisting hypertension, diabetes mellitus with a hemoglobin A1c >7.0% was associated with elevated systolic blood pressure in all, lacunar, and cardioembolic patients and with diastolic blood pressure in all patients. CONCLUSIONS: Blood pressure course of patients sustaining acute stroke varied widely according to stroke subtypes. Poorly controlled diabetes mellitus, as well as preexisting hypertension, appeared to influence blood pressure during the initial week of stroke.

Acute Disease↗
PubMed2006

High blood pressure in acute ischemic stroke and underlying disorders.

BACKGROUND: The Acute Candesartan Cilexetil Therapy in Stroke Survivors (ACCESS) study indicated that early treatment with an angiotensin type 1 receptor blocker in acute stroke patients who had relatively high blood pressure improved cardiovascular morbidity and mortality in the chronic stage. To better interpret the findings of this study, we determined whether stroke patients with high acute blood pressure had specific underlying conditions. METHODS: We divided 712 consecutive patients who were hospitalized within 48 h after the onset of brain infarction into two groups: 77 patients with high acute blood pressure that met the criteria of the ACCESS study and the 635 remaining patients. Underlying risk factors and comorbidities, stroke characteristics, as well as mortality, vascular events, and disability at 3 weeks were compared between the two groups. RESULTS: Patients with high acute blood pressure more frequently had diabetes mellitus (p < 0.01), intracranial arterial stenosis (p < 0.02), higher levels of hemoglobin A1c (p < 0.005), higher creatinine levels (p < 0.005), and tended to more frequently have ischemic heart disease (p < 0.09) and infarcts <1.5 cm in diameter (p < 0.09) than the other patients. On multivariate analysis, high levels of hemoglobin A1c, high creatinine levels, and intracranial arterial stenosis were independently predictive of high acute blood pressure. At 3 weeks after the stroke onset, patients with high acute blood pressure were more dependent in their daily living activities (p < 0.02) and more frequently developed vascular events or death (p < 0.005) than the other patients. CONCLUSIONS: Poorly controlled diabetes mellitus and advanced renal damage appeared to correlate with acute hypertension after stroke. Since intracranial arterial stenosis also seemed to contribute to high acute blood pressure, one should be careful not to induce cerebral hypoperfusion by the early use of antihypertensives.

Aged↗
PubMed2006

Accuracy of conventional plus transoral carotid ultrasonography in distinguishing pseudo-occlusion from total occlusion of the internal carotid artery.

BACKGROUND: To investigate the accuracy of conventional carotid ultrasonography (CCU) combined with transoral carotid ultrasonography (TOCU) for distinguishing pseudo-occlusion from total occlusion of the internal carotid artery (ICA). METHODS: This study included 95 patients who were suspected of having an occlusion of the ICA on magnetic resonance angiography (MRA) and underwent both CCU and conventional digital subtraction angiography (DSA) in order to confirm the diagnosis. TOCU was also performed to observe the cervical portion of the ICA distal to the stenosis. We compared the ultrasonographic findings with the DSA findings. RESULTS: Twelve of the 95 patients were defined as having an ICA pseudo-occlusion on DSA. On B-mode images with CCU color Doppler, slight residual flow signals in the ICA lumen were shown in 20 patients. Among them, 2 patients had a pulsed Doppler waveform of the distal ICA occlusion pattern. Among the remaining 18 patients, 4 had a pulsed Doppler waveform of the to and fro flow pattern, and 14 had a weak antegrade flow pattern in the ICA lumen. The conventional ultrasonographic method showed 100% sensitivity with 93% specificity for diagnosing an ICA pseudo-occlusion. The addition of TOCU findings increased the specificity to 98%. In 2 patients, who were overdiagnosed as having an ICA pseudo-occlusion even using TOCU, DSA revealed an occlusion of the ICA distal to the ophthalmic artery with a severe stenosis of the proximal ICA. CONCLUSIONS: Using conventional and transoral carotid ultrasonography, an ICA pseudo-occlusion can be diagnosed with higher accuracy.

Aged↗
PubMed2006

Changes in brain volume 2 years after extracranial-intracranial bypass surgery: A preliminary subanalysis of the Japanese EC-IC trial.

BACKGROUND AND METHODS: We studied changes in brain volume on magnetic resonance imaging in 10 patients with and without extracranial-intracranial (EC-IC) bypass surgery who met the inclusion criteria for the Japanese EC-IC Bypass Trial, a multicenter, randomized, prospective study of patients with hemodynamic brain ischemia due to cerebral artery occlusive disease. We also examined the association of cerebral hemodynamics on single-photon emission computed tomography with the changes in brain volume. RESULTS: The affected/unaffected ratio of the percent brain volume declined in patients without EC-IC bypass surgery (p < 0.02, n = 4), and the affected/unaffected percent regional cerebral blood flow ratio increased in patients with the surgery (p < 0.03, n = 6). Acetazolamide reactivity increased in the affected hemisphere of patients with surgery (p < 0.01). Two-year increase (decrease) in acetazolamide reactivity of the affected hemisphere showed a significant positive correlation with 2-year changes in the affected/unaffected percent brain volume ratio (R2 = 0.737, p = 0.0007). CONCLUSIONS: Change in acetazolamide reactivity might be a good predictor for brain atrophy in cerebral artery occlusive disease.

Acetazolamide↗
PubMed2006

Venous infarction secondary to septic cavernous sinus thrombosis.

A 65-year-old woman with poorly controlled diabetes presented bilateral miosis, bilateral abducens nerve palsy, and left hemiparesis. On MRI, cavernous sinus thrombosis, subdural empyema and hemorrhagic infarction in the frontotemporal lobe were detected. Cerebral angiogram revealed filling defect in the cavernous sinus with venous congestion but no involvement of internal carotid artery. Postmortem examination demonstrated hemorrhagic infarction in the right frontotemporal lobe as well as hemorrhagic necrosis of the pituitary gland. It should be noted that venous congestion due to cavernous sinus thrombosis may cause these complications.

Aged↗
PubMed2006

Serial evaluation of acute cerebral hyperperfusion by transcranial color-coded sonography.

Using transcranial color-coded sonography (TCCS), we evaluated the acute changes in the hemodynamics of cerebral hyperperfusion in two cases. The mean flow velocity of the cerebral arteries increased at the onset of clinical symptoms, together with an increase in the regional cerebral blood flow (rCBF). In serial follow-up studies, the flow velocity gradually returned to normal in parallel with the normalization of the rCBF values. TCCS can be useful for evaluation of acute cerebral hyperperfusion.

Acute Disease↗
PubMed2006

[Strategy for management of carotid arterial stenosis: analysis of 293 consecutive patients in a Japanese cerebrovascular center].

Carotid arterial stenosis is a major risk factor for ischemic stroke and is increasing in Japan as the life-style has been westernized. The purpose of this study was to clarify the detailed process of diagnosis and treatment of patients with carotid arterial stenosis. Of the consecutive 1,889 hospitalized patients in our cerebrovascular center during 2001 and 2003, 293 patients had carotid stenosis 50% or more in diameter by the NASCET method; 82 patients were hospitalized during the acute stage of ischemic stroke and 211 patients with or without past history of ischemic stroke were admitted in the chronic stage. Among acute ischemic stroke patients, 62 patients (76%) had mild neurological symptoms of NIH Stroke Scale score < or = 4 on admission. As the initial treatment during the acute phase, all patients underwent antithrombotic medication; 33 of them underwent carotid endarterectomy (CEA) or carotid arterial stenting (CAS) in the chronic stage. Of 211 chronic patients, 123 (58%) did not have a history of symptomatic ischemic stroke, and instead had nonspecific symptoms, including carotid bruit, headache, and vertigo, or were diagnosed as having carotid artery stenosis by examinations of preoperative screenings. One hundred and thirty-five chronic patients underwent CEA/CAS and all the others except for a patient with serious gastrointestinal bleeding underwent anti-thrombotic medication. Statin treatment was chosen for 59 acute patients and 66 chronic patients. Because many patients with carotid arterial stenosis had mild symptoms during the acute phase or did not have ischemic episodes, we might overlook carotid lesions unless we performed screening examinations using ultrasound or magnetic resonance angiography.

Acute Disease↗
PubMed2005

Superficial temporal artery duplex ultrasonography for improved cerebral hemodynamics after extracranial-intracranial bypass surgery.

BACKGROUND: To investigate the utility of superficial temporal artery (STA) duplex ultrasonography (STDU) for evaluating the improvement of the cerebral hemodynamics after extracranial-intracranial (EC-IC) bypass. METHODS: This study included 40 consecutive patients who underwent EC-IC bypass for occlusive disease of cerebral arteries. STDU was performed to measure the flow velocity, pulsatility index, and diameter of the operated STA before and 14 days after EC-IC bypass. Regional cerebral blood flow (rCBF) and acetazolamide (ACZ) reactivity of the ipsilateral middle cerebral artery (MCA) territory were evaluated by quantitative single-photon emission computed tomography with the ACZ challenge test. We investigated the correlation between STA flow velocity/diameter and rCBF/ACZ reactivity in the ipsilateral MCA territory. RESULTS: Mean flow velocity (MFV; 26.3 +/- 8.8 to 55.3 +/- 16.3 cm/s, p < 0.0001) and diameter (1.57 +/- 0.24 to 2.26 +/- 0.29 mm, p < 0.0001) of the STA, and rCBF (29.1 +/- 3.1 to 35.0 +/- 6.4 ml/100 g/min, p < 0.0001) and ACZ reactivity (-0.02 +/- 0.10 to 0.28 +/- 0.21, p < 0.0001) of the MCA territory increased after EC-IC bypass compared with the baseline values. STA MFV was significantly correlated with the rCBF 14 days after EC-IC bypass (R = 0.70, p < 0.0001). A cutoff value of postsurgical STA MFV greater than 48.5 cm/s yielded the highest diagnostic accuracy (sensitivity 86%; specificity, 82%) for rCBF > or = 32 ml/100 g/min after EC-IC bypass. CONCLUSIONS: STDU was available for evaluating postsurgical patency of the bypass flow and the rCBF of the ipsilateral MCA territory. The mean blood flow velocity of the operated STA is a highly sensitive parameter for predicting rCBF in the ipsilateral MCA territory after EC-IC bypass.

Aged↗
PubMed2005

Recurrent embolic stroke originating from an internal carotid aneurysm in a young adult.

An unruptured intracranial aneurysm is an uncommon but possible embolic source to the brain. We report a young patient who developed recurrent ischemic strokes occurring mainly in the left internal carotid arterial territory within a short interval; the first stroke occurred midway through a long-distance race, and the second stroke occurred immediately following a bowel movement. The angiographical contrast deficit indicated a thrombus in the left anterior cerebral artery as a result of the embolism. A saccular aneurysm of the left distal internal carotid artery was the only detectable potential embolic source. Initially anticoagulant therapy was given, and then surgical clipping of the aneurysm was performed. The patient has been free from stroke recurrence. As a cause of ischemic stroke in young adults, a carotid saccular aneurysm should be considered. Hard exercise and a Valsalva maneuver may be important triggers of thrombus detachment from the aneurysm.

Carotid Artery Diseases↗
PubMed2005

Transcranial color-coded sonography for vertebrobasilar disorders in end-stage renal disease.

Because vertebrobasilar arterial disorders seem to be common in patients with end-stage renal disease, a neuroradiological evaluation of vertebrobasilar circulation is necessary for patients with possible vertebrobasilar insufficiency. In three patients on maintenance hemodialysis, contrast-enhanced transcranial color-coded real-time sonography (TCCS) through a suboccipital window delineated occlusion of bilateral vertebral arteries with reversal of the basilar artery, reversal of the left vertebral artery mimicking left subclavian steal phenomenon, and dolichoectasia of the basilar artery and bilateral vertebral arteries with signals of turbulent flow. TCCS has several advantages over computed tomographic angiography and magnetic resonance angiography, including the direction of blood flow, handy performance even during hemodialysis, and contrast agent free from nephrotoxicity. Thus, TCCS is useful in the evaluation of intracranial circulation in patients with end-stage renal disease.

Aged↗
PubMed2005

Stroke in patients on maintenance hemodialysis: a 22-year single-center study.

BACKGROUND: Few studies have reported the detailed clinical features of stroke in patients with end-stage renal disease. We examined the frequency of the subtypes, mechanism, and outcome of stroke in patients receiving hemodialysis (HD). METHODS: We studied 151 consecutive patients who developed an acute stroke among the maintenance HD population in our kidney center during 22 years, divided into the initial 17-year (n = 61) and the more recent 5-year (n = 90) groups. For purposes of comparison, we also studied 1,017 stroke patients with normal renal function. RESULTS: Stroke patients receiving HD were younger (age, 64 +/- 10 versus 67 +/- 13 years; P < 0.02) and more frequently had hypertension (87% versus 43%; P < 0.0001) and diabetes (53% versus 23%; P < 0.0001) compared with stroke patients with normal renal function. In the initial HD group, brain hemorrhage was the major subtype of stroke (52%), whereas in the more recent group, brain infarction (BI) replaced hemorrhage as the leading subtype (68%; P < 0.005). In patients with BI, large-artery atherosclerosis was more prevalent in the more recent group than in the initial HD group (33% versus 12%; P < 0.05). A vertebrobasilar territory infarct was more prevalent for HD patients than for those with normal renal function (48% versus 33%; P < 0.05). BI (especially large-artery atherosclerosis and cardioembolism) occurred more frequently during or less than 30 minutes after the dialysis procedure (34%) than brain hemorrhage (19%; P < 0.05). Receiving HD was an independent indicator for poor functional outcome and mortality after stroke. CONCLUSION: In our maintenance HD population, stroke showed several unique characteristics compared with the control population, including a predominance of vertebrobasilar arterial territory infarcts. The dialysis procedure itself seems to be associated more frequently with ischemic rather than hemorrhagic strokes.

Aged↗
PubMed2005

Successful high dose glucocorticoid treatment for subacute neuromyelitis optica with systemic lupus erythematosus.

A 54-year-old Japanese woman with a 6-year history of systemic lupus erythematosus (SLE) was admitted to our hospital suffering from acute blindness in her right eye. Her condition recovered after steroid pulse therapy, however, 18 months later she suffered from nuchal pain for 2 weeks after which right hemiparesis with urinary incontinence developed. A spinal magnetic resonance imaging (MRI) revealed cord swelling from C2 to C7. She was diagnosed with neuromyelitis optica (NMO) and intravenous steroid administrations were immediately commenced. Her condition promptly improved. This case was unique because the steroid treatment was quite effective for this case of myelitis, which had passed the acute phase. We supposed that, because most of the lesion was not necrotic or demyelinated, but rather showed edematous change caused by vasculitis based on autoimmune pathogenesis, the symptoms progressed rather gradually and improved promptly in response to glucocorticoid treatment.

Acute Disease↗
PubMed2005

Prediction of coronary artery disease in patients undergoing carotid endarterectomy.

OBJECT: The authors determined the factors that predict the coexistence of coronary artery disease (CAD) in patients who undergo carotid endarterectomy (CEA). METHODS: Data from 200 consecutive Japanese patients who underwent CEA for extracranial carotid artery stenosis were studied. Among 73 patients with CAD, 35 (48%) had three-vessel or left main CAD (that is, severe CAD). Peripheral artery disease was an independent predictor of CAD (odds ratio [OR] 2.61, 95% confidence interval [CI] 1.08-6.3). In addition, diabetes mellitus ([DM]; OR 2.8, 95% CI 1.24-6.32) and peripheral artery disease (PAD) (OR 2.83, 95% CI 1.05-7.57) were independent predictors of severe CAD in the 200 patients. The percentage of patients with CAD as well as those with the severe form of the disease increased stepwise as the number of major coronary risk factors in patients increased. Asymptomatic CAD was newly detected during the pre-CEA assessment in 18 (25%) of the 73 patients in whom CAD was eventually diagnosed. Diabetes mellitus was an independent predictor of occult CAD among the 200 patients (OR 4.83, 95% CI 1.53-15.2). CONCLUSIONS: In patients with DM, PAD, or multiple major coronary risk factors who have been scheduled for CEA, one should carefully search for concomitant CAD, especially severe CAD, even when the patient has had no previous episode of angina.

Adult↗
PubMed2004

Renal cholesterol embolism in patients with carotid stenosis: a severe and underdiagnosed complication following cerebrovascular procedures.

Here, we report two cases with rapidly progressive renal failure, caused by cholesterol crystal embolism (CCE), after an angiography for carotid artery stenosis. The diagnosis was determined by histological examination and from clinical symptoms, including livedo reticularis and eosinophilia. Neurologists and neuroradiologists tend to underdiagnose CCE, which results from the same atherosclerotic risk factors as cerebrovascular disease. We need to understand more about CCE and identify its unique clinical symptoms to enable an early diagnosis and treatment.

Aged↗