Katsunori Isa

Transoral Carotid Ultrasonography

BACKGROUND AND PURPOSE We attempted ultrasonographic evaluation of the distal extracranial internal carotid artery (ICA) using the transoral method (transoral carotid ultrasonography [TOCU]). METHODS The subjects consisted of five healthy volunteers and seven stroke patients. Examinations were performed with a color Doppler flow imaging system equipped with convex array transducers (7 or 9.5 MHz), originally designed for transrectal use. After local anesthesia of the pharynx, we inserted a probe covered with thin gum transorally, touching the tip to the pharyngeal posterolateral wall. We then attempted to detect the ICA and measure flow velocity of the distal extracranial ICA using principal images obtained by TOCU. RESULTS TOCU was successfully performed in all subjects without any difficulty. In the healthy volunteers, the ICA was identified at a depth of 2.2+/-0.6 cm and visualized as a vertical linear vessel 2.9+/-0.3 cm in length and bent slightly backward. The diameter and mean flow velocity of the distal extracranial ICA were 4.7+/-0.2 mm and 50+/-7 cm/s, respectively. In the stroke patients, some remarkable findings were obtained, including a narrow ICA with low flow velocity in a patient with possible ICA dissection, a lucent echo without flow signal in a patient with acute cardioembolic ICA occlusion, and decreased ICA flow velocity in a patient with ipsilateral MCA stenosis. CONCLUSIONS These preliminary data demonstrate the potential applicability of TOCU to the evaluation of flow in the far distal extracranial ICA. TOCU definitely warrants further investigation in patients with carotid artery disease.

Homonymous Defect of Macular Vision in Ischemic Stroke

It is generally believed that a homonymous defect of macular vision (HMV) is caused by a small lesion restricted to the occipital lobe tip and rarely results from ischemic stroke. The incidence of HMV was studied retrospectively in 54 patients with infarction of the posterior cerebral artery territory who underwent Goldmann’s visual field test. HMV was found in 6 patients (11%). In all of them, HMV was first dismissed due to a confrontation test of visual fields at the bedside and later detected by Goldmann’s visual field test. All had a relatively large infarction extending from the occipital lobe tip to the posterior part of the calcarine cortex and/or the neighboring subcortical regions. Stroke-induced HMV can be caused by a large lesion involving the occipital pole and may not be so rare as generally considered.

Correlation between the Degree of Left Subclavian Artery Stenosis and the Left Vertebral Artery Waveform by Pulse Doppler Ultrasonography

Background:Development of retrograde blood flow may be observed in the vertebral artery and is associated with progressive ipsilateral proximal subclavian or innominate artery stenosis. The subclavian steal phenomenon is more prevalent in the left subclavian artery (LSA). The purpose of this study was to analyze the correlation between the degree of LSA stenosis and pulse Doppler waveforms of the left vertebral artery (LVA). Methods:A retrospective analysis of LVA waveforms was performed in 22 cases with LSA proximal stenosis before the origin of the LVA in conventional angiograms. The degree of LSA stenosis was classified into 5 groups (<50, 50–59, 60–69, 70–89, 90–100%). Pulse Doppler waveforms of the LVA were also classified into 5 subtypes depending on the depth of the mid-systolic notch representing retrograde blood flow (normal, mid-systolic notch, retrograde flow smaller than antegrade flow, retrograde flow larger than antegrade flow, retrograde flow without antegrade flow). Results:A statistically significant correlation (R2 = 0.646, p < 0.0001) was found between the degree of LSA stenosis and the LVA waveform. Conclusions:The pattern analysis of LVA pulse Doppler waveforms seems to be useful in determining the degree of LSA stenosis.

Trends in the Incidence of Stroke and Cardiovascular Risk Factors on the Isolated Island of Okinawa: The Miyakojima Study

BACKGROUND Rapid deterioration of cardiovascular risk control, especially obesity, has occurred in Okinawa; this may affect cardiovascular disease incidence, including stroke. METHODS Cross-sectional field studies were conducted in 2 periods, 1988-1991 as the first period, and 2002-2005 as the second period, in the isolated island of Okinawa, Miyakojima. To evaluate population backgrounds related to cardiovascular risk factors, data from the health checkup programs conducted in 1987 and 2001 were surveyed. RESULTS Total of 257 patients in the first period and 370 in the second were diagnosed with first-time stroke. The age-adjusted annual incidence rate of first-time stroke of the first and second periods was 124 and 144 per 100,000 standard population of Japan. The age-adjusted annual incidence rate showed an upward trend for brain infarction (50 to 73) and downward trend for brain hemorrhage (61 to 54); however, those trends were not significant. The health checkup surveys illustrated that blood pressure decreased in all age groups during the second survey period. However, the body mass index increased in patients aged 50 years or more. Fasting blood glucose levels of patients aged 30-79 years and non-HDL cholesterol levels of patients aged 50-79 years significantly increased. CONCLUSIONS In Miyakojima, the incidence of first-time stroke and all of its subtypes did not change significantly between two periods, even though blood pressure decreased significantly in the second period. Metabolic deterioration may be associated with the upward trend in incidence of brain infarction.

Brain Natriuretic Peptide upon Admission as a Biological Marker of Short-Term Mortality after Intracerebral Hemorrhage

Background and Purpose: The purpose of the present study was to test the hypothesis that plasma brain natriuretic peptide (BNP) is associated with short-term mortality after intracerebral hemorrhage (ICH). Methods: We prospectively enrolled 271 patients (median age 72 years; 109 females) who were admitted within 24 h of ICH onset between April 2007 and July 2011 and in whom plasma BNP levels were measured upon admission. The patients were assigned to two groups according to survival within 1 month of ICH. Factors associated with mortality were determined by multivariate logistic regression analysis. Results: Within 1 month of ICH, 48 (17.7%) of the 271 enrolled patients died. The median (interquartile range) level of plasma BNP was significantly higher in the group of non-survivors than in the group of survivors [102.5 (48.7-205.0) vs. 32.4 (17.3-85.0) pg/ml; p < 0.001]. A cutoff BNP level of 60.0 pg/ml could predict death within 1 month of ICH. Multivariate logistic regression analysis showed that a plasma BNP of >60.0 pg/ml (OR 4.7; 95% CI 1.43-15.63; p = 0.011) was independently associated with mortality within 1 month after ICH. Conclusions: A high BNP level upon admission is associated with mortality within 1 month after ICH.

Association between the intima-media thickness of the brachiocephalic trunk and white matter hyperintensity in brain MRI

The intima-media thickness (IMT) of the brachiocephalic trunk (BCT) can be measured using duplex carotid ultrasonography, which is used for imaging the common carotid artery (CCA). However, the clinical significance of the BCT-IMT has not been studied. We reviewed 1109 stroke-free participants in the registry of the Okinawa General Health Maintenance Association. We compared the association between the BCT-IMT or the CCA-IMT with deep and subcortical white matter hyperintensity (DSWMH). The BCT-IMT was correlated with the CCA-IMT, and like CCA-IMT, it increased with advancing age. The increase in both the BCT-IMT and the CCA-IMT quartiles was correlated with the development of DSWMH. The multivariate logistic regression analysis indicated that, as observed for the CCA-IMT, the increase in the BCT-IMT was associated with a higher prevalence of significant DSWMH (Fazekas grade 2 or 3 per 0.1 mm increase in IMT; OR 1.02, 95% confidence interval 1–1.04; P=0.04). The increase in quartiles of the BCT-IMT was only associated with a higher prevalence of significant DSWMH in subjects with lower CCA-IMT (1st and 2nd quartiles, R2=0.18, P<0.05) but not in subjects with higher CCA-IMT (3rd and 4th quartiles). Combinations of the CCA-IMT and BCT-IMT quartiles failed to have an additive effect on the prevalence of significant DSWMH. The BCT-IMT has a similar clinical profile to the CCA-IMT in terms of its association with DSWMH. However, the CCA-IMT and the BCT-IMT did not predict DSWMH in an additive manner, and distinct mechanisms might underlie the observed thickening of the IMT in the CCA and BCT.

High glycated hemoglobin levels and intracranial artery stenosis are predictive factors for early motor worsening events in patients with penetrating artery infarction.

Background: The purpose of this study was to identify typical clinical characteristics to predict early motor worsening (EMW) of patients with penetrating artery infarction. Methods: We reviewed 65 consecutive patients with pure motor hemiparesis, sensorimotor stroke, and ataxic hemiparesis. EMW was defined as deterioration by ≥1 point on the National Institutes of Health Stroke Scale for motor function within 5 days of admission. Results: EMW was observed in 22 patients (34%). HbA1c levels were higher in patients with EMW than in those without EMW (7.9 ± 2.6 vs. 6.3 ± 1.6%; p < 0.01). The percentage of EMW patients with intracranial artery stenosis (ICAS) was greater than that of non-EMW patients with ICAS (13/22 patients, 59% vs. 8/43 patients, 19%; p < 0.01). Multivariate logistic regression analysis indicated that HbA1c levels ≥7.0% (OR 3.0, 95% CI 1.5–6.8; p < 0.005) or ICAS (OR 2.3, 95% CI 1.2–4.8; p < 0.05) increased the risk of EMW, and the combination of these factors increased the risk in an additive manner (OR 7.6, 95% CI 2.5–40; p < 0.005). Conclusion: HbA1c levels ≥7.0% and/or ICAS in patients with penetrating artery infarction are associated with EMW.

Transoral Carotid Ultrasonography Using A Micro Convex Probe with B-flow Imaging for Extracranial Internal Carotid Artery Dissection

We report on transoral carotid ultrasonography using a micro convex probe with B-flow imaging for determining spontaneous extracranial internal carotid artery dissection just below the petrous portion. A 49-year-old man suffered cortical and subcortical infarction in the region of the right middle cerebral artery. Magnetic resonance angiography on the third day of admission revealed spontaneous recanalization of the right internal carotid artery associated with an intimal flap-like structure at the petrous portion. Transoral carotid ultrasonography using a micro convex probe revealed right extracranial internal carotid artery dissection, showing an increased diameter of the right extracranial internal carotid artery with double lumen formation, stenosis of the true lumen, and a mobile intimal flap in B-flow imaging. Transoral carotid ultrasonography using a micro convex probe was helpful to attempt a self-expanding stent for recanalizing right extracranial internal carotid artery dissection. The patient recovered and was discharged ambulatory. The size of the micro convex probe was optimum for transoral carotid ultrasonography in our patient. Micro convex probe is more commonly used than the standard transoral carotid ultrasonography probe, which lacks versatility. We consider that transoral carotid ultrasonography using a micro convex probe could be routinely used for ultrasonographic evaluation of extracranial internal carotid artery dissection.

357 RELATIONSHIP BETWEEN SERUM URIC ACID AND SILENT BRAIN ISCHEMIA IN MEN: A CROSS-SECTIONAL STUDY

Background: Although serum uric acid (SUA) level as well as silent brain ischemia is known to a risk factor for cardiovascular events, association between SUA and silent brain ischemia has not been fully elucidated. Methods: We evaluated the association between SUA level and deep and subcortical white matter hyperintensity (DSWMH, Fazekas grade) in 1109 stroke free participants (male 56%, age 24 - 85 years) in the registry of Okinawa general health maintenance association. Results: DSWMH was found in 34% of participants (grade 1, 10%; 2, 21%; 3, 3%, respectively). The SUA level was significantly higher in men than in women (6.5 ± 1.2 vs. 4.8 ± 1.1 mg/dl, P < 0.0001). The prevalence of DSWMH (grade 2 - 3) decreased with increasing quartiles of SUA level (1st, 27%, 2nd, 20%, 3rd, 18%, 4th, 18%; P = 0.1) in men, but increased slightly (1st, 28%, 2nd, 29%, 3rd, 32%, 4th, 32%; P = 0.8) in women. We also found negative association between SUA level and Fazekas grade (no DSWMH, 6.6 ± 1.2; grade 2, 6.3 ± 1.3; grade 3, 6.0 ± 1.2 mg/dl, P < 0.05) in men, but not in women. Conclusion: Gender difference about the relationship between SUA levels and silent brain ischemia was observed. Thus SUA may have a beneficial effect of brain ischemia in men but not in women. The prospective study to elucidate association between SUA level and brain ischemia will be needed in the future.