Clinical review of 37 patients with medullary infarction

BACKGROUND

Clinical features of medullary infarction were compared between patients with lateral medullary infarction and medial medullary infarction

METHODS

Thirty-seven patients with medullary infarction (29 with lateral medullary infarction and 8 with medial medullary infarction) who were admitted to our center between April 1, 2007 and March 31, 2010 were examined. Background factors, neurologic signs and symptoms, imaging findings, cause of disease, and outcomes were assessed for patients with lateral and those with medial medullary infarction.

RESULTS

Examination of the clinical symptoms and neurologic findings suggested that among patients with medial medullary infarction, few demonstrated all of the symptoms of Dejerine syndrome at onset, and many had lesions that were difficult to locate based only on neurologic findings. Both lateral and medial medullary infarction were frequently caused by atherothrombosis. However, cerebral artery dissection was observed in 31% of patients with lateral medullary infarction and 12.5% of those with medial medullary infarction. In 13% of patients with lateral and 37% of patients with medial medullary infarction, magnetic resonance imaging diffusion-weighted images on the day of onset did not show abnormalities, and the second set of diffusion-weighted images confirmed infarction lesions. For lateral medullary infarction, a more rostral lesion location was correlated with a poorer 90-day outcome. For medial medullary infarction, a more dorsal lesion location was correlated with a poorer 90-day outcome.

CONCLUSIONS

The diagnosis rate of medullary infarction using imaging examinations at onset--particularly medial medullary infarction--is not necessarily high. The imaging examinations need to be repeated for patients who are suspected to have medullary infarction based on neurologic signs and symptoms.

Clopidogrel resistance and the effect of combination cilostazol in patients with ischemic stroke or carotid artery stenting using the VerifyNow P2Y12 Assay

OBJECTIVE

The inhibitory response to clopidogrel considerably varies among individuals and clopidogrel resistance is a risk factor for thrombotic events in patients with cardiovascular disease. Based on the platelet aggregation evaluated by the VerifyNow P2Y12 Assay, the present study investigated clopidogrel resistance and the effect of cilostazol addition.

METHODS

We measured the ability of 20 µM ADP to aggregate platelets using the VerifyNow P2Y12 Assay. Clopidogrel resistance was defined as % inhibition of <20% in this assay.

PATIENTS

We examined 77 patients (53 men and 24 women, aged 65.8 ± 9.9 years) with ischemic stroke or carotid artery stenting who received clopidogrel (75 mg) for >7 days at our hospital between October 2009 and March 2010. For 62 patients (42 men and 20 women, aged 65.3 ± 9.9 years) 75 mg clopidogrel alone was administered (clopidogrel only group); the other 15 patients (11 men and 4 women, aged 67.9 ± 9.9 years) received 75 mg of clopidogrel plus 100 or 200 mg of cilostazol (cilostazol combination group).

RESULTS

Clopidogrel resistance was identified in 18 (29%) of the 62 patients in the clopidogrel only group. The percent inhibition was significantly higher in the cilostazol combination group than in the clopidogrel only group (41.7 ± 28.0% vs. 64.9 ± 22.7%, p=0.005). None of the patients in the cilostazol combination group had % inhibition of <20%.

CONCLUSION

Clopidogrel resistance developed in 29% of patients given clopidogrel alone. The addition of cilostazol to clopidogrel may have intensified platelet inhibition.

Evaluation of clopidogrel resistance in ischemic stroke patients

OBJECTIVE

Clopidogrel has potent antiplatelet effects, but recent interest has focused on clopidogrel resistance, in which platelet function is not inhibited despite taking the drug. This study evaluated clopidogrel resistance in ischemic stroke patients.

METHODS

After taking oral clopidogrel 75 mg/day for ≥1 week, platelet aggregometry was performed by turbidimetry in all patients, and by a screen filtration pressure method using whole blood in 37 patients. Using turbidimetry, resistance was defined as platelet maximum aggregation rate ≥34% with aggregation-inducing agent ADP 1 µmol/L, or ≥66% with ADP 4 µmol/L. Using the screen filtration pressure method, resistance was defined as a minimum concentration of ≤3 µmol/L ADP to induce secondary aggregation of platelets.

PATIENTS

This study was conducted in 72 patients (52 men, 20 women; mean age, 69 ± 8 years; range, 50-84 years) with non-cardiogenic ischemic cerebrovascular disease.

RESULTS

Based on turbidimetry, the rate of clopidogrel resistance was 8.3% with ADP 1 µmol/L and 18.1% with 4 µmol/L. Based on the screen filtration pressure, the rate of clopidogrel resistance was 8.1%. The differences between turbidimetry and screen filtration pressure methods, regarding the measurement of the presence of resistance in the same patient, were observed.

CONCLUSION

Clopidogrel resistance varies greatly depending on the method of measuring platelet aggregation and the definition of resistance. Rates of 8-18% were obtained using our methods and criteria.

Thrombolysis with 0.6 mg/kg intravenous alteplase for acute ischemic stroke in routine clinical practice: the Japan post-Marketing Alteplase Registration Study (J-MARS)

BACKGROUND AND PURPOSE

In Japan, alteplase at 0.6 mg/kg was approved in October 2005 for use within 3 hours of stroke onset by the Ministry of Health, Labor and Welfare (MHLW). The aim of the Japan post-Marketing Alteplase Registration Study (J-MARS), which was requested by MHLW at the time of approval, was to assess the safety and efficacy of 0.6 mg/kg alteplase in routine clinical practice for the Japanese.

METHODS

A total of 7492 patients from 942 centers were enrolled in the J-MARS, an open-label, nonrandomized, observational study, from October 2005 to October 2007. Primary outcome measures were symptomatic intracranial hemorrhage (a deterioration in NIHSS score >or=4 from baseline) and favorable outcome (modified Rankin Scale score, 0-1) at 3 months after stroke onset.

RESULTS

The proportion of patients with symptomatic intracranial hemorrhage in 7492 patients (safety analysis) was 3.5% (95% confidence interval [CI], 3.1%-3.9%) within 36 hours and 4.4% (95% CI, 3.9%-4.9%) at 3 months. The overall mortality rate was 13.1% (95% CI, 12.4%-13.9%) and the proportion of patients with fatal symptomatic intracranial hemorrhage was 0.9% (95% CI, 0.7%-1.2%). The outcomes at 3 months were available for 4944 patients and the proportion of favorable outcome (efficacy analysis) was 33.1% (95% CI, 31.8%-34.4%). The subgroup analysis in patients between 18 and 80 years with a baseline NIHSS score <25 demonstrated that favorable outcome at 3 months was 39.0% (95% CI, 37.4%-40.6%).

CONCLUSIONS

These data suggest that 0.6 mg/kg intravenous alteplase within 3 hours of stroke onset could be safe and effective in routine clinical practice for the Japanese.

Significance of clinical-diffusion mismatch in hyperacute cerebral infarction

In recent years, patient selection for intravenous tissue plasminogen activator (t-PA) therapy based on clinical-diffusion mismatch (CDM) has been closely examined. We investigated the relationship between prognosis and CDM in patients with hyperacute cerebral infarction within 3 hours of onset and compared CDM with diffusion-perfusion mismatch (DPM). Of 122 patients with hyperacute cerebral infarction who visited the hospital within 3 hours of onset between April 2007 and November 2008, 85 patients with cerebral infarction in the anterior circulation who underwent head magnetic resonance imaging diffusion-weighted imaging (DWI)/magnetic resonance angiography (MRA) (51 men and 34 women; average age, 74 ± 10 years) were enrolled. Seventeen of these patients underwent CT perfusion imaging. CDM-positive cases were those with a National Institute of Health Stroke Scale (NIHSS) score ≥ 8 and a DWI-Alberta Stroke Program Early CT Score (DWI-ASPECTS) ≥ 8; CDM-negative cases were those with an NIHSS score ≥ 8 and an ASPECTS-DWI < 8. The other patients were classified as belonging to the NIHSS score < 8 group. Of the 32 CDM-positive cases, 10 received t-PA infusion. These patients had markedly higher modified Rankin Scale scores 90 days after onset compared with the 22 patients who did not receive t-PA infusion. The 8 CDM-positive cases included 4 DPM-positive cases and 4 DPM-negative cases, and a discrepancy was confirmed between CDM and DPM. In all DPM-positive cases, MRA confirmed lesions in major intracranial arteries. CDM may enable more accurate prediction of outcomes in patients with hyperacute cerebral infarction. In addition, the combination of CDM findings and MRA findings (stenosis or occlusion in major intracranial arteries) may be an alternative to DPM for determining the indications for IV t-PA therapy in patients with hyperacute cerebral infarction.

[Diagnosis and treatment of cerebral infarction]

Diabetes mellitus (DM) is an independent risk factor for cerebral infarction. About 30 % of atherothrombotic and lacunar types of infarction are associated with DM. Cerebral infarction can be diagnosed with the help of computed tomography (CT), magnetic resonance imaging (MRI) and MR angiography (MRA), as well as by carotid and cardiac ultrasonography. The selection of treatment for cerebral infarction is based on time after onset, clinical subtype and severity. Intravenous recombinant tissue plasminogen activator (rt-PA) is indicated for patients with all clinical types of cerebral infarction within 3 hours after onset. Antiplatelet therapy, anticoagulant therapy, neuroprotectants comprise another choice. Controlling risk factors such as hypertension, DM, dyslipidemia and atrial fibrillation during the chronic phase of cerebral infarction is important to prevent recurrence. Pioglitazone significantly reduced the risk of recurrent stroke in patients with DM. Antiplatelet therapy (aspirin, clopidogrel, cilostazol) should be administered to patients with noncardioembolic infarction and anticoagulant therapy should be applied to those with cardioembolic infarction.

Stroke as a manifestation of Takayasu's arteritis likely due to distal carotid stump embolism

The clinical symptoms of Takayasu's arteritis (TA), which mainly affects the aorta and major aortic branches, vary widely depending on the site and degree of arterial lesions. We present herein the case of a young man whose initial symptom was pulmonary artery occlusion and who manifested TA 6 years later as cerebral embolism. Angiography confirmed bilateral common carotid artery (CCA) occlusion and a well-developed collateral circulation. The stump of the occluded CCA has both proximal and distal ends. The possibility of emboli from the occluded CCA (distal stump) seems to be the most probable explanation, as turbulent flow was detected at distal stump on color Doppler sonography. The carotid stump can be a potential source of emboli in TA as well as in atherosclerosis.

Subarachnoid hemorrhage as the initial presentation of cerebral venous thrombosis

Cerebral venous thrombosis presenting as subarachnoid hemorrhage (SAH) is very rare. We present a woman with thrombosis of the superior sagittal, straight, transverse and sigmoid sinuses who presented with SAH in the right temporal sulcus and bilateral cerebellar sulci. Brain perfusion CT demonstrated a delay of the mean transit time and high cerebral blood volume around the right posterior temporal lobe and cerebellum. These findings were compatible with venous congestion and they suggest the possibility that extension of the dural sinus thrombosis into the superficial veins caused localized venous hypertension with dilatation of the thin, fragile-walled cortical veins which eventually ruptured into the subarachnoid space.

[Takotsubo cardiomyopathy and cerebral infarction]

Takotsubo cardiomyopathy is reversible left ventricular dysfunction and apical ballooning resembling acute myocardial infarction. Although Takotsubo cardiomyopathy is a well-known complication of subarachnoid hemorrhage, it is rare in patients with acute cerebral infarction. We reviewed the findings of thirty previously published cases with both Takotsubo cardiomyopathy and cerebral infarction. These cases were divided into three groups (A-C) according to etiology. A; Dysfunction of central autonomic network associated with cerebral infarction caused Takotsubo cardiomyopathy, B; Left ventricular thrombus associated with Takotsubo cardiomyopathy caused cardioembolic stroke. C; The unknown relation of cause and effect. Most patient were elderly women in all groups. Group A mostly included the territory of middle cerebral artery or basilar artery as the infarcts area. The cardiomyopathy in group A often occurred within 24 hours after stroke onset and was commonly asymptomatic. On the other hand, the cardiomyopathy in group B often was commonly symptomatic. But some cases with mild cardiac symptom in group B was diagnosed by embolic event. Takotsubo cardiomyopathy can notably be both the cause and effect of stroke. The 'chicken or egg' issue regarding stroke etiology in group C is sometimes not simple to resolve.

[Roles of angiotensin II receptor blockers in stroke prevention]

Strict blood pressure control is critical for stroke prevention. However, recent basic studies have shown that angiotensin II receptor blockers (ARBs) can protect the brain through mechanisms, such as antioxidant action, improved endothelial cell function and cerebral vessel remodeling, by inhibiting the effects of sympathetic nervous activity and by maintaining cerebral blood flow or blood brain barrier function. Moreover, ARBs reduce the likelihood of new onset of diabetes mellitus and atrial fibrillation. Several clinical trials including the JIKEI HEART Study, MOSES and ACCESS have revealed that ARBs help to prevent stroke via other pathways in addition to lowering blood pressure.

Enhanced dechlorination of chlorobenzene and in situ dry sorption of resultant Cl-compounds by CaO and Na2CO3 sorbent beds incorporated with Fe2O3

The dechlorination of C(6)H(5)Cl and the in situ dry sorption of Cl-compounds produced by C(6)H(5)Cl decomposition in an alkaline sorbent of CaO or Na(2)CO(3) incorporated with Fe(2)O(3) were studied. A sample gas containing C(6)H(5)Cl at an initial concentration of 500 ppm balanced by either N(2), O(2) (5%)-N(2) or H(2)O (10%)-N(2) carrier gas was introduced into a lab-scale quartz tube reactor where CaO or Na(2)CO(3) sorbent was packed with Fe(2)O(3). Subsequently, the effect of Fe(2)O(3) addition to CaO or Na(2)CO(3) on the removal of C(6)H(5)Cl, achieved by the decomposition of C(6)H(5)Cl as well as the dry sorption of Cl-compounds produced by C(6)H(5)Cl decomposition, was investigated. It was found that the decomposition of C(6)H(5)Cl in CaO or Na(2)CO(3) sorbent bed incorporated with Fe(2)O(3) occurred in the lower temperatures, compared to the case when only CaO or Na(2)CO(3) sorbent bed was used. Thus, Fe(2)O(3) was found to play a catalytic role in the oxidative decomposition of C(6)H(5)Cl. Further, the decomposition of C(6)H(5)Cl in a bed containing only Fe(2)O(3) was promoted by the presence of O(2) and H(2)O in the reaction atmosphere. Moreover, a higher amount of Cl was absorbed in the combined CaO/Fe(2)O(3) and Na(2)CO(3)/Fe(2)O(3) beds, compared to the absorption of Cl-compounds in only CaO or Na(2)CO(3) sorbent bed. Finally, the comparison of CaO and Na(2)CO(3) sorbents showed that the decomposition of C(6)H(5)Cl and the in situ dry sorption of the resultant Cl-compounds in the combined Na(2)CO(3) and Fe(2)O(3) beds were higher than those in the combined CaO and Fe(2)O(3) beds.

Spontaneous spinal epidural hematoma with unusual hemiparesis alternating from one side to the other side

A 59-year-old woman suffered from sudden onset of severe neck and back pain. She experienced right-side hemiparesis. Although the right-side hemiparesis soon disappeared, left-side hemiparesis developed. MRI of the brain was unremarkable. MRI of the cervical spine demonstrated hematoma in the left posterior epidural space at the C2/3 level. The spinal cord was compressed not only by a degenerative disc of the ventral region, but also by hematomas of the dorsal region. The unusual hemiparesis alternating from right-side to left-side in this case may have been caused by various factors, including cervical canal stenosis, the spread of hematoma, disturbance of blood flow, and distribution of stress and strain.

[Thrombolysis by intravenous tissue plasminogen activator (t-PA)--current status and future direction]

In Japan, the intravenous tissue plasminogen activator (t-PA) Alteplase (0.6 mg/kg) administration of the within 3 h of the onset of acute ischemic stroke was approved for therapeutic use in the year 2006. t-PA induces thrombolysis in patients with acute ischemic stroke, and this method has gradually gained recognition among physicians and the general population. However, the number of patients who were treated using Alteplase is low (4,000-5,000 patients/year), and this figure accounts for only 2-3% of the annual number of cases of ischemic stroke. There is little doubt that Alteplase treatment is a potentially effective modality for some patients with acute ischemic stroke. The post-marketing surveillance of 4,749 Japanese patients treated using Alteplase showed that 33% of the patients had modified Rankin scale (mRS) scores of 0-1, 17% of patiens died and 4.5% presented with symptomatic intracerebral hemorrhage (ICH); these results were comparable to those from other countries. The expansion of the therapeutic time window has been a matter of concern. The investigators of the European Cooperative Acute Stroke Study (ECASS) have reported that there was significant improvement in the clinical outcomes of patients with acute ischemie stroke when Alteplase was administered 3-4.5 h after the onset of the symptoms. Mismatches in perfusion- and diffusion-weighted (DW) magnetic resonance imaging (MRI) images have been used for selecting patients 3 h after the onset of symptoms, and the findings from MRI, dwimages (DWI) and MR angiography are practical predictors of t-PA therapy within 3 h of onset. The Middle Cerebral Artery Embolism Local Fibrinolytic Intervention Trial (MELT) Japan study showed that local intra-arterial fibrinolysis is effective in patients with embolic MCA occlusion within 6 h of the onset of symptoms. Combining the initiation of intravenous t-PA administration with further intra-arterial fibrinolysis or mechanical thrombolectomy may improve the recanalization rate. Thrombolysis in combination with ultrasound-enhanced clot lysis is another attractive therapy. In Japan the neuroprotective agent edaravone (radical scavenger) is commonly used in combination with t-PA, and it is expected to decrease the hemorrhagic transformation after t-PA administration. Acute cerebral ischemic symptoms may occasionally precede thoracic aortic dissection. Thoracic aortic dissection after t-PA administration may prove to be fatal, and it is an important disorder that must be differentially diagnosed.

[Transarterial NBCA embolization with transvenous partial outflow obstruction for superior petrosal sinus dural arteriovenous fistula: a case report]

We encountered a case of superior petrosal sinus dural arteriovenous fistula (SPS DAVF) which was treated by a combination of a transvenous and a transarterial approach after the failure of the transvenous approach alone. A 69-year-old man presented with a complaint of progressive left bulbar conjunctival conjestion, exophthalmos, and impaired vision. Cerebral angiography revealed a left SPS DAVF fed by the left middle meningeal artery, the meningeal branches of the left internal carotid artery and the left posterior meningeal artery. Venous drainage proceeded through the cavernous sinus (CS) toward the left superior ophthalmic vein (SOV). Transvenous embolization via the SOV was indicated because the left ipsilateral inferior petrosal sinus contributed to the normal venous return. However the microcatheter to the CS couldn't go through the tortuous SOV. Next a transarterial NBCA (n-butyl-cyanoacrylate) embolization of the affected sinuses was performed under arterial flow control with balloons and the partial coil embolization of the origin of the SOV. The coils in the SOV trapped NBCA and the sinuses were filled slowly with NBCA. The postoperative angiogram confirmed complete obliteration of the DAVF and the patient's ocular symptoms disappeared. DAVF is usually difficult to treat by transarterial embolization with NBCA because of its multiple feeders and high flow drainage. We should therefore carefully observe its structure and the blood flow change with 3D-DSA and the selective angiography while embolizing the DAVE.

Cerebral pachyleptomeningitis associated with MPO-ANCA induced by PTU therapy

A 34-year-old woman with hyperthyroidism, who had been previously treated with propylthiouracil (PTU) is reported. She was admitted because of clumsiness in her left hand and abnormal behavior. A neurological examination demonstrated impairment of higher cortical function, and weakness and hyperreflexia of the left leg. An MRI scan with gadolinium enhancement showed pachyleptomeningeal thickening in the right frontoparietal lobe. Blood tests revealed a high MPO-ANCA titer of 122 EU (normal:<10 EU). After steroid administration, the neurological symptoms and the MRI findings improved markedly. This is the first report of PTU-induced cerebral pachyleptomeningitis associated with a high serum MPO-ANCA titer.