Questionnaire Survey from the 1st Kurume University Inflammatory Bowel Disease Center Educational Lecture

INTRODUCTION

The number of inflammatory bowel disease (IBD) patients is increasing steadily in Japan, and it is expected that patient groups and patient education will improve the quality of life of patients and IBD care. The 1st Kurume University IBD Center educational lecture was held and a questionnaire survey was administered at this lecture.

METHODS

We asked 78 participants to answer a questionnaire survey on the occasion of the 1st Kurume University IBD Center educational lecture.

RESULTS

We obtained responses from 56 (71.8%) participants; 31 (55.4%) had IBD [21 (37.4%) had ulcerative colitis (UC) and 10 (17.9%) had Crohn's disease (CD)]. Most participants were female (37, 66%). The age range with the highest number of participants was 40 to 69 (27, 48.2%). Most had heard about this educational lecture through "notification by the patient's doctor" 23 (41.1%). A total of 30 (53.6%) of participants answered "good" about the lecture content, while 50 (89.7%) of participants answered "very good" and "good" about the impression of this lecture. Meanwhile, 10 (32.3%) of patients were interested in patient groups. The percentage of patients who were interested in patient groups was higher in patients with CD 4 (66.7%) than those with UC 2 (33.3%).

CONCLUSION

We held the 1st Kurume University IBD center educational lecture. Further studies are needed to assess whether educational lectures and/or patient groups can improve patients' quality of life (QOL) and IBD care in our hospital.

Platelet Hyperaggregability in Ischemic Cerebrovascular Disease and Effects of Aspirin

Platelet aggregation was studied in 24 patients in the chronic stage of ischemic cerebrovascular disease (CVD), with cerebral affluent and effluent blood, i.e., carotid arterial and internal jugular venous blood, and also with peripheral venous blood. Aggregation tests were performed at various final concentrations of sodium arachidonate (A.A.) and ADP. In 17 patients, not taking aspirin, platelet aggregability in jugular venous blood was significantly accentuated compared with that in arterial and peripheral venous blood. This tendency was more marked in the patients with cerebral artery stenosis and/or occlusion than in those with normal cerebral angiogram. In 7 patients taking 500 mg or more oral aspirin, aggregation differences across the brain were not observed and A.A. aggregation and the second phase of ADP aggregation were completely suppressed. These results suggest that a prophylactic administration of aspirin may be beneficial for patients in chronic stage of CVD.

Intravenous thrombolysis for patients with reverse magnetic resonance angiography and diffusion-weighted imaging mismatch: SAMURAI and NCVC rt-PA Registries

BACKGROUND AND PURPOSE

The characteristics of reverse magnetic resonance angiography and diffusion-weighted imaging (MRA-DWI) mismatch (RMM), defined as a large DWI lesion in the absence of major artery occlusion (MAO), remain unknown, especially in patients treated with intravenous recombinant tissue plasminogen activator (rt-PA).

METHODS

Patients with stroke in the middle cerebral artery territory were included. Early ischaemic changes (EIC) were assessed with the Alberta Stroke Program Early CT Score on DWI (DWI-ASPECTS). All patients were divided into four groups based on the presence of MAO and a DWI-ASPECTS cut-off value of <7. RMM was defined as DWI-ASPECTS <7 without MAO. Clinical characteristics, symptomatic intracerebral hemorrhage (sICH) and favorable functional outcome (modified Rankin Scale score 0-2) at 90 days were compared amongst the four groups.

RESULTS

Of the 486 patients enrolled (167 women, median age 74 years, median initial National Institutes of Health Stroke Scale score 13), reverse MRA-DWI mismatch was observed in 24 (5%). Of the clinical characteristics, cardioembolism was the only factor that was independently associated with RMM [odds ratio (OR) 5.49, 95% confidence interval (CI) 1.25-24.1]. Multivariable analyses revealed that patients with RMM more commonly had sICH than those with DWI-ASPECTS ≥ 7 irrespective of the presence (OR 5.44, 95% CI 1.13-26.1) or absence (13.1, 2.07-83.3) of MAO, and they had a more favorable functional outcome than those with DWI-ASPECTS < 7 plus MAO (7.45, 2.39-23.2).

CONCLUSION

RMM was observed in 5% of patients treated with rt-PA and associated with cardioembolism. Patients with RMM may benefit from thrombolysis compared with those with EIC with MAO, although increment in the rate of sICH is a concern.

Run-up to participation in ATACH II in Japan

Intracerebral hemorrhage (ICH) is a major cause of morbidity and mortality in Japan. Seventeen Japanese institutions are participating in the Antihypertensive Treatment for Acute Cerebral Hemorrhage (ATACH) II Trial (ClinicalTrials.gov no. NCT01176565; UMIN 000006526). This phase III trial is designed to determine the therapeutic benefit of early intensive systolic blood pressure (BP) lowering for acute hypertension in ICH patients. This report explains the long run-up to reach the start of patient registration in ATACH II in Japan, including our preliminary study, a nationwide survey on antihypertensive treatment for acute ICH patients, a multicenter study for hyperacute BP lowering (the SAMURAI-ICH study), revision of the official Japanese label for intravenous nicardipine, and construction of the infrastructure for the trial.

Arterial Occlusion Sites on Magnetic Resonance Angiography Influence the Efficacy of Intravenous Low-Dose (0·6 mg/kg) Alteplase Therapy for Ischaemic Stroke

Aims

To determine the predictors of efficacy, including magnetic resonance imaging information, for low-dose intravenous alteplase therapy for stroke patients.

Methods

Seventy-eight patients were prospectively enrolled in a single Stroke Unit (SU) receiving alteplase at a dose of 0·6 mg/kg during the initial 27 months after its approval in Japan. Ischaemic changes and vascular lesions were identified using computed tomography, diffusion-weighted magnetic resonance imaging, and magnetic resonance angiography. Early ischaemic signs were assessed using the Alberta Stroke Program Early CT Score.

Results

The median baseline National Institutes of Health Stroke Scale score of 78 patients was 12. In 19 patients (24%), the National Institutes of Health Stroke Scale score improved by ≥8 points at 24 h. After multivariate adjustment, occlusion at the internal carotid artery (odds ratio 11·82, 95% confidence interval 1·73–142·74), Alberta Stroke Program Early CT Score on diffusion-weighted imaging ≤6 (15·23, 1·88–351·50), and a lower National Institutes of Health Stroke Scale score (1·24, 1·08–1·47, per 1-point decrease) were inversely correlated with early improvement. Four patients (5%) had symptomatic intracranial haemorrhage. At 3 months, 76 patients (98%) survived, and 36 of 78 patients (46%) overall, but only two of 19 patients (11%) with internal carotid artery occlusion, had a favourable functional outcome, corresponding to a modified Rankin scale score 1. After multivariate adjustment, internal carotid artery occlusion (odds ratio 15·84, 95% confidence interval 3·12–128·69) and Alberta Stroke Program Early CT Score on diffusion-weighted imaging ≤6(15·62, 1·78–410·12) were independent predictors of poor outcome.

Conclusions

Intravenous alteplase therapy at a dose of 0·6 mg/kg resulted in a relatively good overall outcome when compared with outcomes reported by western studies using an alteplase dose of 0·9 mg/kg. However, patients with occlusion at the internal carotid artery did not respond to this low-dose alteplase therapy.

Frontal bone window improves the ability of transcranial color-coded sonography to visualize the anterior cerebral artery of Asian patients with stroke

The frontal bone window (FBW) is a promising approach in evaluating the anterior cerebral artery. The goal of the present study was to determine the rates of detection of the basal cerebral arteries by using the FBW alone and a combination of the FBW with the temporal bone window (TBW) in 163 patients. The combined application improved detection rates of A1 (58.6% versus 46.0%, P = .001) and A2 (43.6% versus 6.7%, P < .001) compared with the TBW alone.

Eccentric stenosis of the carotid artery associated with ipsilateral cerebrovascular events

BACKGROUND AND PURPOSE

Eccentric stenosis of the coronary artery is associated with plaque disruption and acute coronary syndrome. The purpose of the present study was to determine whether eccentric stenosis of the carotid artery contributes to cerebrovascular events.

MATERIALS AND METHODS

Of 6859 patients with vascular diseases who underwent duplex carotid ultrasonography, we studied 512 internal carotid arteries in 441 patients who had a maximum area stenosis at or more than 70%, which corresponds with approximately 50% or more by the NASCET method. The maximal (A) and minimal wall thicknesses (B) were measured on cross-sectional sonography images, and an eccentricity index was calculated using the following formula: (A - B)/A. Arteries in the lowest quartile of the eccentricity index (<0.69) were defined as having a concentric stenosis, whereas the others were defined as having eccentric stenosis. The underlying clinical characteristics and plaque morphologies, as well as the occurrence of ipsilateral ischemic stroke or transient ischemic attack in the preceding year, were compared between patients with eccentric and concentric stenosis.

RESULTS

Patient characteristics and plaque morphology were similar between the 2 groups. Cerebrovascular events occurred more frequently ipsilaterally to the artery with eccentric stenosis (13.5%) than to the artery with concentric stenosis (5.5%; P = .013); the difference was more evident when cerebrovascular events of presumed carotid arterial origin were assessed (P = .005). After adjusting for risk factors and plaque morphology, eccentric stenosis was independently related to the presence of recent cerebrovascular events (odds ratio = 2.76; 95% confidence interval = 1.19-6.40).

CONCLUSIONS

In patients with an area carotid stenosis of 70% or more, eccentric plaque was associated with a significantly increased incidence of ipsilateral cerebrovascular events compared with patients with concentric stenosis.

How to improve repetition ability in patients with Wernicke's aphasia: the effect of a disguised task

Dissociation "automatico-voluntaire" is a symptom observed in aphasic patients. We elucidated the difference between voluntary and involuntary speech output in a quantitative manner using the same task materials in nine patients with Wernicke's aphasia. All the patients exhibited better ability and less paraphasias in a repetition task elicited in a disguised condition than in an ordinary repetition condition. This result indicates that the output difficulty in Wernicke's aphasia might be a disability of volitional control over the language system.

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.

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.

Prospective comparative study of brain protection in total aortic arch replacement: deep hypothermic circulatory arrest with retrograde cerebral perfusion or selective antegrade cerebral perfusion

BACKGROUND

The purpose of this study was to compare the results of total aortic arch replacement using two different methods of brain protection, particularly with respect to neurologic outcome.

METHODS

From June 1997, 60 consecutive patients who underwent total arch replacement through a midsternotomy were alternately allocated to one of two methods of brain protection: deep hypothermic circulatory arrest with retrograde cerebral perfusion (RCP: 30 patients) or with selective antegrade cerebral perfusion (SCP: 30 patients). Preoperative and postoperative (3 weeks) brain CT scan, neurological examination, and cognitive function tests were performed. Serum 100b protein was assayed before and after the cardiopulmonary bypass, as well as 24 hours and 48 hours after the operation.

RESULTS

Hospital mortality occurred in 2 patients in the RCP group (6.6%) and 2 in the SCP group (6.6%). New strokes occurred in 1 (3.3%) of the RCP group and in 2 (6.6%) of the SCP group (p = 0.6). The incidence of transient brain dysfunction was significantly higher in the RCP group than in the SCP group (10, 33.3% vs 4, 13.3%, p = 0.05). Except in patients with strokes, S-100b values showed no significant differences in the two groups (RCP: SCP, prebypass 0.01+/-0.04: 0.05+/-0.16, postbypass 2.17+/-0.94: 1.97+/-1.00, 24 hours 0.61+/-0.36: 0.60+/-0.37, 48 hours 0.36+/-0.45: 0.46+/-0.40 microg/L, p = 0.7). There were no intergroup differences in the scores of memory decline (RCP 0.74+/-0.99; SCP 0.55+/-1.19, p = 0.6), orientation (RCP 1.11+/-1.29; SCP 0.50+/-0.76, p = 0.08), or intellectual function (RCP 1.21+/-1.27; SCP 1.05+/-1.15, p = 0.7).

CONCLUSIONS

Both methods of brain protection for patients undergoing total arch replacement resulted in acceptable levels of mortality and morbidity. However, the prevalence of transient brain dysfunction was significantly higher in patients with the RCP.

Microembolic signals and diffusion-weighted MR imaging abnormalities in acute ischemic stroke

BACKGROUND AND PURPOSE

The clinical significance of microembolic signals (MESs) detected by transcranial Doppler sonography (TCD) in acute ischemic stroke remains unclear. The purpose of the present study was to assess the findings of diffusion-weighted MR imaging (DWI) and other clinical characteristics in patients with acute ischemic stroke and MESs.

METHODS

We performed TCD and DWI within 48 hours and 7 days, respectively, after stroke onset in 28 patients with acute brain infarction. The relationship between the number of MESs and DWI findings, risk factors for stroke, National Institutes of Health Stroke Scale (NIHSS) score on admission, and arterial disease was examined.

RESULTS

Ten patients had MESs detected by TCD (MES group) and 18 had no MESs (control group). The frequency of hypertension, diabetes mellitus, hyperlipidemia, and smoking; NIHSS score; blood-coagulation parameters; and interval between stroke onset and DWI study did not differ between the two groups. However, arterial disease was more frequent in the MES group than in the control group. Small, multifocal ischemic lesions (<10 mm in diameter) on DWI were more frequent in the MES group than in the control group. Conventional CT and MR imaging often failed to show these lesions.

CONCLUSION

Small, often asymptomatic DWI abnormalities were more frequent in patients with MESs detected by TCD and with large-vessel occlusive diseases than in stroke patients without MESs. TCD and DWI may provide early clues to the mechanism of stroke in the acute phase.

[A case of agnosia for streets and houses unaccompanied by prosopagnosia of familiar faces due to the right occipital lobe infarction]

We reported a patient who showed agnosia for streets and homes unaccompanied by prosopagnosia of familiar faces following infarction in the right occipital lobe. A 70-years-old right-handed man admitted to our department because of sudden development of visual impairment. He had left hemianopsia, left unilateral spatial neglect and slight visual memory disturbance but no other neurological abnormalities. His verbal memory was maintained intact. He was, however, unable to distinguish the sceneries of buildings and streets regardless of their familiarities and often got lost in the hospital. His topographical abilities in map-sketching and route-description were partially impaired depending upon the familiarity of targets; the disability was observed toward unfamiliar targets. His ability in facial recognition was also partially impaired depending upon the familiarity of persons. The patient was unable to distinguish faces of unfamiliar persons, such as nurses and doctors whom he met following stroke, whereas he was able to distinguish faces of familiar persons, such as his family and friends. The brain MRI demonstrated infarction in the right medial occipital lobe including parahippocampal gyrus, lingual gyrus and fusiform gyrus. In general, the manifestation of agnosia for streets and houses is associated with prosopagnosia. The present case, however, exhibited only the former in association with the partial manifestation of the latter. The fact suggests that those two are independent syndromes. The present case also showed a dissociation in the abilities of topographical and facial recognition according to the familiarity of targets. The process for the retrieval and reference of acquired information and that for the acquirement of new visual information may work in an independent manner.

[A case of antiphospholipid antibody syndrome showing a neurological deterioration and infarct development over a month]

A 67-year-old man was admitted to our hospital because of a sudden onset of gait disturbance and behavioral abnormalities. On the admission, he had a moderate consciousness disturbance and right hemiparesis with left internal carotid artery occlusion. Eight days after the stroke, the patient further developed left hemiparesis in association with right internal carotid artery occlusion. Despite anticoagulation therapy and plasma volume loading, neurological symptoms deteriorated over a month, during which CT scan demonstrated a progressive expansion of infarct size. Laboratory tests revealed the presence of lupus anticoagulant. Antiphospholipid antibody syndrome may be associated with a progression of ischemic stroke.

Side-to-side differences of the common carotid artery diameter in presence of asymmetry of the circle of Willis or different vasculopathies

Based on angiographic and carotid ultrasonographic findings in 60 patients with stroke or other diseases, we studied what factors affected the side-to-side differences of the common carotid artery diameter (CCAD). The side-to-side differences of the CCAD were within 0.7 mm in patients with normal cerebral angiogram, but a difference above 0.7 mm was found in many patients with asymmetry of the circle of Willis or different vasculopathies, such as the carotid artery occlusion, cerebral arteriovenous malformation and aortitis.

Successful application of three-dimensional transcranial power Doppler imaging in two stroke patients

We applied a new technique of three-dimensional (3-D) transcranial power Doppler imaging to demonstrate the middle cerebral artery (MCA) in the 2 stroke patients. In the first patient, the 3-D power Doppler study clearly showed the horizontal portion, bifurcation, proximal portion of the upper and lower trunks, and the major branches of the lower trunk of the MCA. In the second patient, the 3-D power Doppler clearly revealed the proximal bifurcation of the left MCA. The 3-D transcranial power Doppler seems to be useful in making clear 3-D images of the MCA.

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.

[Right-to-left shunt and atrial septal aneurysm in stroke patients: a contrast transesophageal echocardiographic study]

BACKGROUND

Transesophageal echocardiography (TEE) has been used to detect cardiac abnormalities including right-to-left shunt (RLS) and atrial septal aneurysm (ASA). The aim of this study was to elucidate frequency of RLS and ASA detected by contrast-TEE, and to evaluate the role of these abnormalities in stroke patients.

METHODS AND RESULTS

We investigated prevalence of RLS and ASA in 504 patients suspected of stroke by using TEE. (mean age 62 +/- 12 y.o., stroke 491, non-stroke 13). The RLS was detected in 64 patients (12.7%), in whom 49 patients (9.7%) had the patent foramen ovale (PFO). The ASA was demonstrated in 10 patients (2.0%), and accompanied well with the RLS (six of the 10, 60%). The prevalent ratios of the RLS (33.8%), the PFO (26.8%), and the ASA (11.3%) in 71 patients with embolic stroke (brain embolism or TIA) of unknown cause were significantly higher than those in the other 433 patients (9.2%, 6.9%, 0.5%, respectively, p < 0.0001). Multiple logistic regression analysis showed that both the PFO and the ASA were independent risk factors (odds ratio: 3.8: p = 0.0002 and 16.6: p = 0.0008, respectively) for embolic stroke of unknown cause.

CONCLUSION

It seems that the RLS, PFO and the ASA play a roll in developing embolic stroke of unknown cause.

[Detection of microemboli by transcranial Doppler sonography after carotid endarterectomy]

Transcranial Doppler sonography (TCD), a non-invasive monitoring technique, has potential for detecting microemboli caused by the extracranial internal carotid artery. Many previous reports have shown that TCD-detected microemboli may be a risk factor for stroke. The main purpose of this study is to verify whether microemboli cease after carotid endarterectomy (CEA). TCD monitoring was performed in 43 cases before and after CEA. TCD monitoring was carried out for an hour at the ipsilateral middle cerebral artery of each case using a 2-MHz pulse-wave transcranial Doppler device, and high intensity transient signals were counted as microemboli. Microemboli were detected preoperatively in 10 cases (23.3%). Microemboli were not detected in any case immediately after CEA, in either the subacute stage (from 14 to 21 days after CEA) or in the chronic stage (more than 3 months after CEA). In the acute stage (from 3 to 7 days after CEA), microemboli were detected in three cases (7.0%). The rate of TCD-detected microembolic was always significantly reduced after CEA. TCD monitoring can be helpful in assessing the effect of CEA for prevention of stroke by removing the suspected source of microemboli.

[Analysis of factors related to microemboli in cases with internal carotid artery stenosis]

Transcranial Doppler ultrasound (TCD) has been used to detect microemboli in cases with extracranial internal carotid artery stenosis. However, the mechanism causing microemboli has remained unclear. The purpose of this study is to clarify clinical characteristics and circumstances associated with the genesis of TCD-detected microemboli. Ninety-one cases with more than 30% stenosis of the internal carotid arteries were studied. TCD monitoring was carried out for an hour at the ipsilateral middle cerebral artery of each case using a 2-MHz pulse-wave transcranial Doppler device, and high intensity transient signals were counted as microemboli. Digital subtraction angiography, magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) were also performed in all cases. Microemboli were detected in 30 of 91 cases. Microemboli were significantly well detected in cases with a history of ischemic event and/or cerebral infarction recognized by MRI. Detection of microemboli had no relation to sex, age or clinical risk factors (hypertension, hypercholesterolemia, diabetes mellitus and smoke habituation). In contrast, detection of microemboli was significantly related to decrease in cerebral blood flow recognized by SPECT, severity of stenosis and wall irregularity of lesion recognized by angiography. Microemboli can be found in a significantly high percentage of these clinical conditions, which may be risk factors for embolic stroke caused by extracranial internal carotid artery stenosis.

[Detection of microemboli in patients with extracranial carotid artery stenosis by transcranial Doppler sonography]

Embolism from a stenotic lesion of the extracranial internal carotid artery (ICS) is considered to be an important pathomechanism of cerebral infarction. The purpose of this study is to estimate the risk of cerebral infarction associated with microembolism in patients with ICS and thereby to determine the importance of TCD-detected microemboli in this condition. Seventy-one cases with more than 30% ICS and 10 cases without ICS were studied. TCD monitoring was carried out for an hour at the ipsilateral middle cerebral artery of each case using a 2-MHz pulse-wave transcranial Doppler device. High intensity transient signals were counted as microemboli. Microemboli were detected in 27 of 71 cases with ICS, but not in cases without ICS. Microemboli were detected more frequently in cases with 70% to 99% ICS (53.3%) compared with in cases with 30% to 69% ICS (12.5%). Cerebral infarctions were recognized in the ipsilateral hemisphere in 23 of 27 cases with microemboli (85.2%) by means of MRI. In contrast, cerebral infarctions were recognized only in 21 of 45 cases without microemboli (47.7%). These results suggest that a stenotic lesion of the extracranial internal carotid artery, especially high-grade stenosis, is a major source of cerebral embolism and that detection of microemboli by TCD is a useful tool capable of reliably assessing the risk of cerebral infarction due to ICS.

Periventricular white matter lucency and cerebral blood flow autoregulation in hypertensive patients

The goal of this study was to elucidate the association between the development of periventricular white matter lucency and autoregulation of cerebral blood flow in hypertensive patients through the arteriovenous oxygen saturation difference method. We studied 51 hypertensive patients who had previously suffered from minor strokes (lacunar infarction, 43; deep basal minor hemorrhage, 8). Patients were divided into three groups based on the findings of periventricular white matter lucency. We measured the absolute value of resting cerebral blood flow using the argon inhalation method, and stepwise reduction of blood pressure was obtained with patients on a tilting table. Intracerebral venous blood sampling was accomplished by direct cannulation into the jugular vein up to the jugular bulb. We calculated several cerebral circulatory parameters, such as cerebrovascular resistance and cerebral oxygen consumption, and also delineated individual autoregulation curves. Cerebrovascular resistance was significantly greater in patients with severe periventricular white matter lucency than in patients without it (P < .05). Impaired autoregulation was also significantly more prevalent in patients with more severe periventricular lesions (P < .05). Multiple regression analysis revealed that the impaired autoregulation was significant and an independent determinant of the severity of such periventricular lesions (R = .34, P < .05). In conclusion, our findings indicated that hypertensive patients with severe periventricular white matter lucency were more likely to have impaired autoregulation of cerebral blood flow and suggest that stricter blood pressure control is required in such patients to prevent deterioration of the cerebral microcirculation.

Effects of dihydropyridines on cerebral blood vessels

AIM

To evaluate the effects of dihydropyridine calcium antagonists on the cerebral circulation in stroke patients. DESIGN OF STUDIES: Mean cerebral circulation parameters were studied in chronic stroke patients with hypertension and treated acutely or chronically (2 weeks) with nicardipine or nifedipine retard. The effects of nicardipine on local cerebral blood flow were also studied in patients with a subacute brain infarction.

RESULTS

Mean cerebral blood flow was significantly increased after a single oral administration of nicardipine but not after nifedipine retard. Both calcium antagonists reduced mean arterial pressure. Nifedipine retard acted mainly by reducing blood pressure and nicardipine mainly by reducing cerebrovascular resistance.

CONCLUSION

Dihydropyridines have a beneficial effect in the control of hypertension in stroke patients.

[Analysis of factors affecting anaerobic threshold in healthy subjects]

The anaerobic threshold (AT) is used to determine the exercise capacity in patients with heart failure and healthy subjects. To determine the factors affecting AT, we determined the AT in healthy subjects, and examined the factors that determine AT in healthy subjects. One hundred and sixteen healthy subjects (79 men and 37 women) performed on a bicycle a stepwise increasing submaximal exercise. During the work test the parameters usually used in the detection of AT (Vo2, Vco2, VE), blood pressure, heart rate and oxygen saturation were recorded by a computerized system every minute. AT was determined from changes in ventilation and gas-exchange. The fat index was calculated from height and body weight measured at the beginning of the ventilatory function test. A significant correlation was obtained between AT and age, AT and fat index, AT and %VC, AT and maximum heart rate during exercise, AT and recovery rate of heart rate after exercise, and AT and Vo2 at rest. In addition, we examined the relationship among the parameters in 4 groups according to sex and age (30-49; younger, 50-69; older), because sex and age affected most parameters. We found a significant correlation between AT and fat index (older men and women), AT and %VC (younger and older women), AT and Vo2 at rest (younger and older men). We considered that the main factors that determined AT in healthy subjects were age, sex, fat index, %VC and Vo2 at rest.

[An approach of in vivo measurement for ultrasonic myocardial tissue characterization]

The purpose of this study is to characterize regional myocardial alternations of reflected ultrasound throughout a cardiac cycle in normal and ischemic myocardium. Integrated ultrasonic backscatter (2-5 MHz) gated R wave of ECG was measured at the base, middle and apex in 4 dogs, and the apex before and after ischemia in other 4 dogs. Quantitative ultrasonic backscatter (IB) was reflected to a steel reflector. At the apex and middle, where a cyclic pattern of IB was discernible, maximum values were recorded near end diastole and minimum near end systole. The amplitude of the variation of IB throughout a cardiac cycle for each region increase progressively from base to middle to apex. Time-averaged IB over a cardiac cycle (averaged IB) was similar for each area of the heart (base = -50.6 +/- 0.5 dB (mean +/- SE), middle -49.4 +/- 0.5 dB, apex -49.7 +/- 0.6 dB. p = NS for comparison of any two regions). After occluding left anterior descending coronary artery for 30 minutes, the variation of IB was markedly blunted and averaged IB increased significantly (-47.5 +/- 0.5 dB. p less than 0.01 compared with preocclusion (-50.8 +/- 0.5 dB]. These results suggested that IB and averaged IB may permit assessment of intrinsic geometrical changes throughout a cardiac cycle (contractile properties) and histological changes respectively.

Vascular response to carbon dioxide in areas with and without diaschisis in patients with small, deep hemispheric infarction

The reactivity of cerebral blood vessels to changes in PaCO2 in areas of the cerebral cortex with or without diaschisis was investigated in 13 patients in a subacute or chronic stage after a small capsular infarct. A focal area of hypoperfusion (area of diaschisis) was detected in the ipsilateral sensorimotor cortex in each patient. Hyperventilation caused a significant reduction of regional cerebral blood flow in the area without diaschisis and only a tendency for regional cerebral blood flow to decrease in the area with diaschisis; CO2 inhalation induced a slight increase in regional cerebral blood flow in the area without diaschisis and a significant increase in regional cerebral blood flow in the area with diaschisis. Regional cerebral blood flow reactivity to hypocapnia was significantly less in the area with diaschisis than in the area without, whereas the hypercapnic response was more marked in the area with diaschisis than in the area without. Our results suggest that in the area with diaschisis, the arterioles may be abnormally vasoconstricted at rest such that they cannot constrict further in response to hypocapnia but can dilate more during hypercapnia than in the area without diaschisis. This excessive resting vasoconstriction may result from decreased tissue elaboration of CO2 due to local decrease of metabolic function.

A new approach to antithrombotic therapy--evaluation of combined therapy of thromboxane synthetase inhibitor and very low dose of aspirin

The effect of a selective thromboxane (TX) synthetase inhibitor (OKY-046), alone and in combination with a very low dose of aspirin, on the platelet function was studied in healthy and diseased subjects. A single dose of 100 mg OKY-046 was orally administered to patients with ischemic cerebrovascular disease (CVD) and healthy volunteers. TXB2 generation and platelet aggregation were measured before and at 1, 4, 6 and 8hr after dosing. In addition, after the administration of a very low dose of aspirin (0.1-0.25 mg/kg/day) for at least one month, a single dose of OKY-046 was given to CVD patients. TXB2 generation and platelet aggregation were measured in the same manner as OKY-046 alone. The effect of OKY-046 on platelet aggregation induced by arachidonic acid (AA) was different in each subject whereas platelet TXB2 generation was almost completely inhibited in all of the patients and healthy volunteers. OKY-046 had a slight inhibitory effect on collagen induced aggregation. A combination of OKY-046 with a very low dose of aspirin, on the other hand, produced additional inhibition of the platelet aggregation induced by both AA and collagen. The present results suggest that the accumulation and metabolism of cyclooxygenase products that accumulate when TX synthetase is blocked, differ in each subject, additional inhibition is caused by the combined use of TX synthetase inhibitor and a very low dose of aspirin because the very low dose of aspirin partially reduces the proaggregatory cyclooxygenase products that accumulate when TX synthetase is blocked.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of isosorbide dinitrate and isosorbide-5-mononitrate on prostacyclin (PGI2) and thromboxane A2 (TXA2) generation in rat and human arteries

The mechanism by which nitrates produce relaxation of the vascular smooth muscle and anti-aggregatory effect on platelets has not been understood. Several reports have suggested that vasoactive prostaglandin generation may account for part of the pharmacological action of nitroglycerin. However, few studies have been reported that isosorbide dinitrate or its main metabolite, isosorbide-5-mononitrate, directly stimulates prostacyclin (PGI2) generation in blood vessels. We examined the effect of ISDN and 5-ISMN on PGI2 and thromboxane A2 (TXA2) generation in rat thoracic aorta and human thoracic aorta and coronary artery. The stimulation of PGI2 generation was dependent on the concentration of ISDN and the maximum PGI2 generation was effected by ISDN 5.0 ng/ml in both rat and human vessels. The ratio of peak to basal PGI2 generation was about 1.6 with rat thoracic aorta and about 1.6 with human thoracic aorta and about 1.3 with human coronary artery. On the other hand, TXA2 generation showed a smaller increase than that of PGI2 with ISDN used in the therapeutic dose range and 5-ISMN did not significantly affect PGI2 or TXA2 generation. Previous studies of the effect of cyclooxygenase inhibitor, for example indomethacin, on the vasodilating response to nitrates have given conflicting results. It is believed, however, that ISDN is partially, not wholly, associated with the hemodynamic and platelet antiaggregation effects due to vascular PGI2 generation, which may play a beneficial role in inhibiting coronary vasospasm during anginal attacks.

The effect of a thromboxane synthetase inhibitor, OKY-046, on urinary excretion of immunoreactive thromboxane B2 and 6-keto-prostaglandin F1 alpha in patients with ischemic cerebrovascular disease

Thromboxane synthetase activity is selectively inhibited by (E)-3-[4-(1-imidazolylmethyl)phenyl]-2-propenoic acid hydrochloride monohydrate (OKY-046). A single dose of 100 mg OKY-046 was orally administered to patients with ischemic cerebrovascular disease and healthy volunteers. Platelet aggregation and thromboxane B2 (TXB2) generation of intact and homogenised platelets induced by 1.0 mM sodium arachidonate were measured before and at 1, 4, 6 and 8 h after dosing. OKY-046 inhibited arachidonate-induced aggregation in platelet rich plasma from some, but not all, individuals, whereas platelet TXB2 generation was almost completely inhibited by a single dose of 100 mg OKY-046, in all of the patients and healthy volunteers. Endogenous TXA2 and prostacyclin (PGI2) biosynthesis were assessed by measurement of urinary immunoreactive TXB2 (i-TXB2) and 6-keto-PGF1 alpha (i-6-keto-PGF1 alpha) before and at 0-3, 3-6, 6-9 h after dosing. OKY-046 increased the urinary i-6-keto-PGF1 alpha coincidently with a decrease of urinary i-TXB2, both in patients and healthy volunteers. These effects of a selective thromboxane synthetase inhibitor will improve a disturbed balance between TXA2 and PGI2, associated with the development of ischemic cerebrovascular disease.

Role of prostacyclin in the response of cerebral blood flow to CO2

The prostacyclin (PGI2) formation in cerebral vessels, as reflected by the difference in concentration of internal carotid arterial and internal jugular venous radioimmunoassayed 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), was determined under normocapnic and hypercapnic conditions in 5 patients with mild cerebral thrombotic infarction. There was no evidence that endogenous PGI formation in cerebral vessels was stimulated at mild hypercapnia, while an increase of cerebral blood flow (CBF) induced by hypercapnia was observed. These results suggest that endogenous PGI2 may not be a mediator for the response of CBF to CO2.

Platelet hyperaggregability in ischemic cerebrovascular disease and effects of aspirin

Platelet aggregation was studied in 24 patients in the chronic stage of ischemic cerebrovascular disease (CVD), with cerebral affluent and effluent blood, i.e., carotid arterial and internal jugular venous blood, and also with peripheral venous blood. Aggregation tests were performed at various final concentrations of sodium arachidonate (A.A.) and ADP. In 17 patients, not taking aspirin, platelet aggregability in jugular venous blood was significantly accentuated compared with that in arterial and peripheral venous blood. This tendency was more marked in the patients with cerebral artery stenosis and/or occlusion than in those with normal cerebral angiogram. In 7 patients taking 500 mg or more oral aspirin, aggregation differences across the brain were not observed and A.A. aggregation and the second phase of ADP aggregation were completely suppressed. These results suggest that a prophylactic administration of aspirin may be beneficial for patients in chronic stage of CVD.

Plasma concentrations of 6-keto-prostaglandin F1 alpha in patients with hypertension, cerebrovascular disease or Takayasu's arteritis

The peripheral venous plasma levels of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were determined by radioimmunoassay in 23 control subjects, 14 patients with essential hypertension, 19 patients with cerebrovascular disease (CVD) not taking aspirin, 12 patients with DVD taking aspirin, and 12 patients with Takayasu's arteritis. There was no significant difference in 6-keto-PGF1 alpha levels between the control subjects and hypertensive patients. In CVD patients and patients with Takayasu's arteritis, the plasma 6-keto-PGF1 alpha levels were significantly lower than those in control subjects. The internal jugular venous and femoral arterial plasma levels of 6-keto-PGF1 alpha and thromboxane B2 (TxB2) were measured in 10 CVD patients not taking aspirin. The patients with occlusive lesions of major arteries exhibited higher TxB2/6-keto-PGF1 alpha ratios in the internal jugular venous plasma.