Jyoji Nakagawara

Alteplase at 0.6 mg/kg for Acute Ischemic Stroke Within 3 Hours of Onset: Japan Alteplase Clinical Trial (J-ACT)

Background and Purpose— Based on previous studies comparing different recombinant tissue plasminogen activator (rt-PA) doses, we performed a clinical trial with 0.6 mg/kg, which is lower than the internationally approved dosage of 0.9 mg/kg, aiming to assess the efficacy and safety of alteplase in acute ischemic stroke for the Japanese. Methods— Our prospective, multicenter, single-arm, open-label trial was designed with a target sample size of 100 patients. The primary end points were the proportion of patients with a modified Rankin Scale (mRS) score of 0 to 1 at 3 months and the incidence of symptomatic intracranial hemorrhage (sICH) within 36 hours. Thresholds for these end points were determined by calculating 90% CIs of weighted averages derived from published reports. The protocol was defined according to the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA stroke study with slight modifications. Results— Among the 103 patients enrolled, 38 had an mRS of 0 to 1 at 3 months; this proportion (36.9%) exceeded the predetermined threshold of 33.9%. sICH within 36 hours occurred in 6 patients; this incidence (5.8%) was lower than the threshold of 9.6%. Conclusions— In patients receiving 0.6 mg/kg alteplase, the outcome and the incidence of sICH were comparable to published data for 0.9 mg/kg. These findings indicate that alteplase, when administered at 0.6 mg/kg to Japanese patients, might offer a clinical efficacy and safety that are compatible with data reported in North America and the European Union for a 0.9 mg/kg dose.

Ischemic Stroke and Incomplete Infarction

BACKGROUND The concept of selective vulnerability or selective loss o f individual neurons, with survival of glial and vascular elements as one of the consequences of a systemic ischemic-hypoxic insult (eg, transient cardiac arrest or severe hypotension), has been recognized for decades. In contrast, selective neuronal death as one of the lesions that may develop in the brain after occluding an intracranial artery is an idea not readily acknowledged in the current medical literature dealing with human stroke. SUMMARY OF REVIEW A review of pertinent publications reveals that selective neuronal injury after middle cerebral artery occlusion was observed in autopsy specimens over 40 years ago, although its pathogenesis remains unclear. Recent observations in both humans and animals suggest that selective neuronal necrosis (rather than infarct) is the consequence of either a short-term arterial occlusion or permanent occlusion accompanied by ischemia of moderate severity. During the acute and subacute states of an ischemic stroke, the loss of a limited number of neurons (ie, incomplete infarction) does not result in structural changes discernible by either CT or conventional MRI. However, the loss of a selected number of neurons may be demonstrable in vivo by calculating the corresponding loss of benzodiazepine receptors. The use of specific radiotracers in combination with single-photon emission CT or positron emission tomography allows demonstration of a decrease in gamma-aminobutyric acid-ergic receptor sites at places where many neurons have been lethally injured. CONCLUSIONS We aim to alert physicians to the potential development of incomplete brain infarctions in patients with intracranial arterial occlusions. Recognizing incomplete infarcts is particularly important in the context of stroke therapy with thrombolytic and neuroprotective agents. This brain lesion is likely to be the consequence of an arterial occlusion with a resultant ischemia of moderate severity (eg, regional blood flows in the range of 15 to 20 mL x 100 g-1 x min-1).

Alteplase at 0.6 mg/kg for Acute Ischemic Stroke Within 3 Hours of Onset

Background and Purpose— Based on previous studies comparing different recombinant tissue plasminogen activator (rt-PA) doses, we performed a clinical trial with 0.6 mg/kg, which is lower than the internationally approved dosage of 0.9 mg/kg, aiming to assess the efficacy and safety of alteplase in acute ischemic stroke for the Japanese. Methods— Our prospective, multicenter, single-arm, open-label trial was designed with a target sample size of 100 patients. The primary end points were the proportion of patients with a modified Rankin Scale (mRS) score of 0 to 1 at 3 months and the incidence of symptomatic intracranial hemorrhage (sICH) within 36 hours. Thresholds for these end points were determined by calculating 90% CIs of weighted averages derived from published reports. The protocol was defined according to the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA stroke study with slight modifications. Results— Among the 103 patients enrolled, 38 had an mRS of 0 to 1 at 3 months; this proportion (36.9%) exceeded the predetermined threshold of 33.9%. sICH within 36 hours occurred in 6 patients; this incidence (5.8%) was lower than the threshold of 9.6%. Conclusions— In patients receiving 0.6 mg/kg alteplase, the outcome and the incidence of sICH were comparable to published data for 0.9 mg/kg. These findings indicate that alteplase, when administered at 0.6 mg/kg to Japanese patients, might offer a clinical efficacy and safety that are compatible with data reported in North America and the European Union for a 0.9 mg/kg dose.

Effects of 0.6 mg/kg Intravenous Alteplase on Vascular and Clinical Outcomes in Middle Cerebral Artery Occlusion Japan Alteplase Clinical Trial II (J-ACT II)

Background and Purpose— The purpose of this study was to evaluate further the efficacy of 0.6 mg/kg intravenous alteplase on vascular and clinical outcomes in patients with middle cerebral artery occlusion in a postmarketing Phase IV trial of prospective cohort study design. Methods— Alteplase was given intravenously at 0.6 mg/kg to patients with ischemic stroke within 3 hours of onset with MR angiography-documented middle cerebral artery occlusion. Vascular outcome was evaluated by MR angiography at 6 and 24 hours after symptom onset based on the modified Mori grade. The primary end points also included a favorable outcome (modified Rankin Scale 0 to 1 at 3 months after onset) and incidence of symptomatic intracranial hemorrhage within 36 hours after treatment. The impact of recanalization on clinical outcome was assessed by stepwise logistic regression analysis. Results— Fifty-eight patients were enrolled. Recanalization was noted in 51.7% on 6-hour MR angiography and 69.0% on 24-hour MR angiography. A favorable clinical outcome was achieved in 46.6%. None had symptomatic intracranial hemorrhage. In logistic regression models, recanalization on either 6-hour or 24-hour MR angiography was an independent predictor for clinical outcome as well as the baseline National Institutes of Health Stroke Scale score. Conclusions— Early recanalization of an occluded middle cerebral artery can be provoked by 0.6 mg/kg intravenous alteplase and may induce a favorable clinical outcome. The rates of recanalization and favorable outcome are comparable to that previously reported with the 0.9-mg/kg dose.

Routine Use of Intravenous Low-Dose Recombinant Tissue Plasminogen Activator in Japanese Patients General Outcomes and Prognostic Factors From the SAMURAI Register

Background and Purpose— A retrospective, multicenter, observational study was conducted to document clinical outcomes and to identify outcome predictors in patients treated with low-dose intravenous recombinant tissue plasminogen activator (0.6 mg/kg alteplase), which was approved in Japan in 2005, within 3 hours of stroke onset. Methods— Consecutive patients with stroke treated with recombinant tissue plasminogen activator in 10 Japanese stroke centers were included. Results— A total of 600 patients (377 men, 72±12 years old) were studied. Median National Institutes of Health Stroke Scale scores decreased from 13 before recombinant tissue plasminogen activator to 8 at 24 hours later. Symptomatic intracerebral hemorrhage within 36 hours with a ≥1-point increase from the baseline National Institutes of Health Stroke Scale score developed in 23 patients (3.8%; 95% CI, 2.6% to 5.7%). At 3 months, 43 patients had died (7.2%; 5.4% to 9.5%), and 199 patients (33.2%; 29.5% to 37.0%) had a modified Rankin Scale score ≤1. Analysis of 399 patients with a premorbid modified Rankin Scale score ≤1 who met the criteria of the European license (≤80 years old, an initial National Institutes of Health Stroke Scale score ≤24, etc) showed that 40.6% (35.9% to 45.5%) had a 3-month modified Rankin Scale score ≤1. After multivariate adjustment, younger age, lower initial National Institutes of Health Stroke Scale score, absence of internal carotid artery occlusion, higher Alberta Stroke Program Early CT Score on CT, and absence of intravenous antihypertensives just before recombinant tissue plasminogen activator were independently related to a 3-month modified Rankin Scale score ≤1. Congestive heart failure and hyperglycemia were independently related to mortality. Conclusions— Three-month outcomes of patients receiving low-dose intravenous recombinant tissue plasminogen activator therapy in the present study were similar to those from postmarketing surveys using 0.9 mg/kg alteplase.

Reduced Estimated Glomerular Filtration Rate Is Associated with Stroke Outcome after Intravenous rt-PA: The Stroke Acute Management with Urgent Risk-Factor Assessment and Improvement (SAMURAI) rt-PA Registry

Background: The aim of this study was to determine whether renal dysfunction affects the outcome of stroke patients treated with recombinant tissue plasminogen activator (rt-PA). Methods: A retrospective, multicenter, observational study was conducted to identify the effects of underlying risk factors on intravenous rt-PA therapy using 0.6 mg/kg alteplase in 10 stroke centers in Japan. Consecutive stroke patients with a premorbid modified Rankin Scale (mRS) score ≤3 who received rt-PA were studied. Renal dysfunction was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2 on admission. The outcome measures were any intracerebral hemorrhage (ICH) and symptomatic ICH within the initial 36 h; favorable (mRS 0–1) outcome, poor outcome (mRS 4–6) and mortality at 3 months. Results: Of a total of 578 patients (372 men; 64.4%, 71.4 ± 11.7 years old), renal dysfunction was present in 186 patients (32.2%). These patients were older and more commonly had hypertension, atrial fibrillation, prior ischemic heart disease and prior use of antithrombotic agents than patients without renal dysfunction. ICH (27.4 vs. 16.6%) and symptomatic ICH (8.1 vs. 2.6%) was more common in patients with renal dysfunction than in those without. At 3 months, patients with renal dysfunction had higher median mRS scores than those without (3 vs. 2). After multivariate adjustment for established outcome predictors, renal dysfunction was related to any ICH (odds ratio 1.81, 95% confidence interval 1.16–2.84), symptomatic ICH (2.64, 1.10–6.56), poor outcome (1.55, 1.01–2.38), and mortality (2.94, 1.38–6.42). Conclusions: Reduced eGFR was associated with early ICH and 3-month unfavorable outcome in stroke patients receiving intravenous rt-PA.

Pretreatment ASPECTS on DWI predicts 3-month outcome following rt-PA: SAMURAI rt-PA Registry

Objective: To evaluate whether the pretreatment Alberta Stroke Programme Early CT Score (ASPECTS) assessed using diffusion-weighted imaging (DWI) predicts stroke outcomes at 3 months following IV recombinant tissue-type plasminogen activator (rt-PA) therapy. Methods: Stroke patients treated with rt-PA (0.6 mg/kg alteplase) in 10 stroke centers in Japan were retrospectively studied. ASPECTS was assessed on DWI just prior to rt-PA injection. The primary outcome was a modified Rankin Scale (mRS) score of 0–2 at 3 months. Secondary outcomes included death at 3 months and symptomatic intracerebral hemorrhage (sICH) within 36 hours. Results: For the 477 patients (316 men, 71 ± 11 years old) enrolled, the median NIH Stroke Scale score was 13 (interquartile range 7–18.5), the median ASPECTS on DWI was 8 (7–10), and sICH was identified in 15 patients (3.1%). At 3 months, 245 (51.4%) had an mRS score of 0–2, and 29 (6.1%) had died. Patients with an mRS score of 0–2 had higher median ASPECTS (9; interquartile range 8–10) than other patients (8; 6–9, p < 0.001). Using receiver operating characteristic curves, the optimal cutoff ASPECTS to predict an mRS score of 0–2 was ≥7. On multivariate regression analysis, ASPECTS ≥7 was related to an mRS score of 0–2 (odds ratio 1.85; 95% confidence interval 1.07–3.24), ASPECTS ≤4 was related to death (3.61; 1.23–9.91), and ASPECTS ≤5 was related to sICH (4.74; 1.54–13.64). Conclusion: ASPECTS on DWI was independently predictive of functional and vital outcomes at 3 months, as well as sICH within 36 hours, following rt-PA therapy for stroke patients.

Systolic Blood Pressure After Intravenous Antihypertensive Treatment and Clinical Outcomes in Hyperacute Intracerebral Hemorrhage The Stroke Acute Management With Urgent Risk-Factor Assessment and Improvement-Intracerebral Hemorrhage Study

Background and Purpose— Blood pressure (BP) lowering is often conducted as part of general acute management in patients with acute intracerebral hemorrhage. However, the relationship between BP after antihypertensive therapy and clinical outcomes is not fully known. Methods— Hyperacute (<3 hours from onset) intracerebral hemorrhage patients with initial systolic BP (SBP) >180 mm Hg were included. All patients received intravenous antihypertensive treatment, based on predefined protocol to lower and maintain SBP between 120 and 160 mm Hg. BPs were measured every 15 minutes during the initial 2 hours and every 60 minutes in the next 22 hours (a total of 30 measurements). The mean achieved SBP was defined as the mean of 30 SBPs, and associations between the mean achieved SBP and neurological deterioration (≥2 points’ decrease in Glasgow Coma Score or ≥4 points’ increase in National Institutes of Health Stroke Scale score), hematoma expansion (>33% increase), and unfavorable outcome (modified Rankin Scale score 4–6 at 3 months) were assessed with multivariate logistic regression analyses. Results— Of the 211 patients (81 women, median age 65 [interquartile range, 58–74] years, and median initial National Institutes of Health Stroke Scale score 13 [8–17]) enrolled, 17 (8%) showed neurological deterioration, 36 (17%) showed hematoma expansion, and 87 (41%) had an unfavorable outcome. On multivariate regression analyses, mean achieved SBP was independently associated with neurological deterioration (odds ratio, 4.45; 95% confidence interval, 2.03–9.74 per 10 mm Hg increment), hematoma expansion (1.86; 1.09–3.16), and unfavorable outcome (2.03; 1.24–3.33) after adjusting for known predictive factors. Conclusions— High achieved SBP after standardized antihypertensive therapy in hyperacute intracerebral hemorrhage was independently associated with poor clinical outcomes. Aggressive antihypertensive treatment may ameliorate clinical outcomes.

Guidelines for the intravenous application of recombinant tissue-type plasminogen activator (alteplase), the second edition, October 2012: a guideline from the Japan Stroke Society.

In Japan, intravenous alteplase, a recombinant tissue-type plasminogen activator (rt-PA), was approved for an indication of ischemic stroke in 2005 on the basis of the results of a clinical trial with a unique dose of the drug (0.6 mg/kg). The Japan Stroke Society published the guidelines for intravenous application of rt-PA and organized training sessions for proper use all over Japan in an effort to promote the safe, widespread use of intravenous alteplase. Seven years following its approval, clinical experience with intravenous alteplase has accumulated, additional evidence of intravenous alteplase has been found in Japan and overseas, and the medical environment has substantially changed, including approvals for new drugs and medical devices. Notably, the use of alteplase in the extended therapeutic time window (within 4.5 hours of symptom onset) became covered by insurance in Japan in August 2012. To address these changing situations, we have decided to prepare the revised guidelines. In preparing the second edition, we took care to make its contents more practical by emphasizing information needed in clinical practice. While the first edition was developed with emphasis on safety in light of limited clinical experience with intravenous alteplase in Japan in 2005, this second edition is a substantial revision of the first edition mainly in terms of eligibility criteria, on the basis of accumulated evidence and the clinical experience.

Multicenter Evaluation of a Standardized Protocol for Rest and Acetazolamide Cerebral Blood Flow Assessment Using a Quantitative SPECT Reconstruction Program and Split-Dose 123I-Iodoamphetamine

SPECT can provide valuable diagnostic and treatment response information in large-scale multicenter clinical trials. However, SPECT has been limited in providing consistent quantitative functional parametric values across the centers, largely because of a lack of standardized procedures to correct for attenuation and scatter. Recently, a novel software package has been developed to reconstruct quantitative SPECT images and assess cerebral blood flow (CBF) at rest and after acetazolamide challenge from a single SPECT session. This study was aimed at validating this technique at different institutions with a variety of SPECT devices and imaging protocols. Methods: Twelve participating institutions obtained a series of SPECT scans on physical phantoms and clinical patients. The phantom experiments included the assessment of septal penetration for each collimator used and of the accuracy of the reconstructed images. Clinical studies were divided into 3 protocols, including intrainstitutional reproducibility, a comparison with PET, and rest–rest study consistency. The results from 46 successful studies were analyzed. Results: Activity concentration estimation (Bq/mL) in the reconstructed SPECT images of a uniform cylindric phantom showed an interinstitution variation of ±5.1%, with a systematic underestimation of concentration by 12.5%. CBF values were reproducible both at rest and after acetazolamide on the basis of repeated studies in the same patient (mean ± SD difference, −0.4 ± 5.2 mL/min/100 g, n = 44). CBF values were also consistent with those determined using PET (−6.1 ± 5.1 mL/min/100 g, n = 6). Conclusion: This study demonstrates that SPECT can quantitatively provide physiologic functional images of rest and acetazolamide challenge CBF, using a quantitative reconstruction software package.