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

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.

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.

Low DWI-ASPECTS is associated with atrial fibrillation in acute stroke with the middle cerebral artery trunk occlusion

BACKGROUND AND PURPOSE

For optimal acute stroke management and secondary prevention, discrimination of stroke etiology is crucial. We hypothesized that a low Alberta Stroke Program Early CT Score (ASPECTS) on diffusion-weighted imaging (DWI) immediately after stroke onset was associated with the presence of atrial fibrillation (AF).

METHODS

Consecutive patients admitted within 24h from stroke onset with an occlusion at the horizontal segment of the middle cerebral artery (M1) on initial MRA were retrospectively enrolled. AF was diagnosed based on continuous electrocardiogram monitoring during acute hospitalization or its confirmed history.

RESULTS

Of the 206 patients (95 women, median age 77 [IQR 69-85] years, NIHSS score 18 [13-23]) enrolled, AF was identified in 138 patients (AF group): chronic AF in 89, known paroxysmal AF (pAF) in 13, and masked pAF on admission in 36. The ASPECTS score on the initial DWI, performed a median of 2.5h after onset, was lower in the AF group than in the others (4 [2-6] vs. 7 [4-8], p<0.001). With the optimal cut-off value of ≤ 6 (sensitivity, 78%; specificity, 57%; area under the ROC curve, 0.682), DWI-ASPECTS was independently associated with the presence of any AF (OR 5.05, 95%CI 2.36 to 10.8), as well as the presence of any pAF (OR 8.64, 95%CI 3.00 to 24.9) and that of masked pAF on admission (OR 10.0, 95%CI 3.06 to 32.9).

CONCLUSION

Extensive early ischemic change assessed by DWI-ASPECTS predicts the presence of AF, even initially masked pAF, in acute stroke patients with M1 occlusion.

Intravenous alteplase at 0.6 mg/kg for acute stroke patients with basilar artery occlusion: the stroke acute management with urgent risk factor assessment and improvement (SAMURAI) Recombinant tissue plasminogen activator registry

BACKGROUND

The therapeutic efficacy of low-dose intravenous alteplase (0.6 mg/kg) for basilar artery occlusion (BAO) remains unknown.

METHODS

BAO patients enrolled from the Japanese multicenter registry involving 600 stroke patients treated with the low-dose intravenous alteplase were studied.

RESULTS

Twenty-five patients had BAO (8 women ranging from 32-92 years of age; mean baseline National Institutes of Health Stroke Scale [NIHSS] score 16). The stroke subtype was cardioembolic in 15 patients and atherothrombotic in 4 patients. BAO was recanalized during hospitalization in 18 (78%) of 23 patients undergoing follow-up angiography. Within the initial 24 hours, 14 patients (56%) had a ≥ 8-point decrease in the NIHSS score, being more common than 267 patients with middle cerebral artery occlusion (MCO) from the same registry (odds ratio [OR] 2.50; 95% confidence interval [CI] 1.06-5.97) after adjustment by sex, age, and baseline NIHSS score. In addition, 4 patients (16%) had a ≥ 4-point increase in the score, being marginally more common than MCO patients (OR 3.13; 95% CI 0.81-10.25). Symptomatic intracranial hemorrhage within the initial 36 hours (8% v 5%), independence at 3 months (modified Rankin Scale score ≤ 2, 48% v 52%), and mortality at 3 months (4% v 6%) were similar when comparing BAO and MCO patients. When compared with previous studies of BAO, vital and functional outcomes at 3 months were relatively better in our study.

CONCLUSIONS

The use of low-dose alteplase resulted in similar outcomes when comparing acute BAO and MCO patients.

Stroke outcomes of Japanese patients with major cerebral artery occlusion in the post-alteplase, pre-MERCI era

This study examined outcomes of patients with acute ischemic stroke (AIS) with major cerebral artery occlusion after the approval of intravenous recombinant tissue-type plasminogen activator (IV rt-PA) but before approval of the MERCI retriever. We retrospectively enrolled 1170 consecutive patients with AIS and major cerebral artery occlusion (496 women; mean age, 73.9 ± 12.3 years) who were admitted within 24 hours after the onset of symptoms to 12 Japanese stroke centers between October 2005 and June 2009. Cardioembolism was a leading cause of AIS in this group (68.2%). The occlusion sites of the major cerebral arteries included the common carotid artery and internal carotid artery (ICA; 29.6%), middle cerebral artery (52.2%), and basilar artery (7.6%). Recanalization therapy (RT) was performed in 32.0% of patients (IV rt-PA, 20.0%; neuroendovascular therapy, 9.4%; combined, 2.5%). Symptomatic intracerebral hemorrhage within 36 hours with a ≥ 1-point increase in the National Institutes of Health Stroke Scale score occurred in 5.3% of the patients. At 3 months (or at hospital discharge), 29.3% of the patients had a favorable outcome (based on a modified Rankin scale score of 0-2), 23.8% were bedridden, and 15.6% died. After multivariate adjustment, RT was positively associated with a favorable outcome and negatively associated with death, whereas age, baseline National Institutes of Health Stroke Scale score, and ICA occlusion were negatively associated with a favorable outcome and positively associated with death. One-third of the patients with AIS and major cerebral artery occlusion were treated with RT, which was independently associated with favorable outcomes and death. However, 40% of the patients became bedridden or died during the post-alteplase, pre-MERCI era in Japan.

Effect of serum lipid levels on stroke outcome after rt-PA therapy: SAMURAI rt-PA registry

BACKGROUND

The effects of lipid levels on clinical outcomes after ischemic stroke are controversial. Whether admission lipid levels and prior statin use are associated with early intracerebral hemorrhage (ICH) and long-term functional outcome after recombinant tissue plasminogen activator (rt-PA) therapy for stroke patients was investigated.

METHODS

Ischemic stroke patients who received intravenous rt-PA from a multicenter registry were studied. Lipid levels on admission, including total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, and triglyceride levels, as well as prior statin use, were assessed. The primary outcome was favorable outcome at 3 months corresponding to a modified Rankin Scale score ≤1. The secondary outcome was any or symptomatic ICH within the initial 36 h.

RESULTS

Of 489 enrolled patients (171 women, 70.8 ± 11.6 years old), 60 used statins prior to stroke, 93 developed ICH (19.0%), and 188 (38.4%) had a favorable 3-month outcome. Of the lipid levels, only the HDL-C level was an independent predictor of favorable outcome after multivariate adjustment for baseline characteristics (OR 1.95, 95% CI 1.10-3.47 per 1 mmol/l; p = 0.023) and after further adjustment for pretreatment radiological findings (OR 2.03, 95% CI 1.07-3.84; p = 0.029). For the 187 stroke patients without cardioembolism, the HDL-C level was more strongly associated with favorable outcome (OR 4.94, 95% CI 1.91-12.76 per 1 mmol/l; p = 0.001). There were no significant associations between ICH and any lipid levels. Prior statin use was not associated with outcomes.

CONCLUSIONS

The admission HDL-C level was associated with favorable outcome 3 months after intravenous rt-PA therapy in stroke patients without cardioembolism.

Early ischemic change on CT versus diffusion-weighted imaging for patients with stroke receiving intravenous recombinant tissue-type plasminogen activator therapy: stroke acute management with urgent risk-factor assessment and improvement (SAMURAI) rt-PA registry

BACKGROUND AND PURPOSE

Alberta Stroke Programme Early CT Score (ASPECTS) is a quantitative topographical score to evaluate early ischemic change in the middle cerebral arterial territory on CT as well as on diffusion-weighted imaging (DWI). The aim of the present study was to elucidate the relationship between CT-ASPECTS and DWI-ASPECTS for patients with hyperacute stroke and their associations with outcomes after recombinant tissue-type plasminogen activator therapy based on a multicenter registry.

METHODS

ASPECTS was assessed on both CT and DWI before intravenous 0.6 mg/kg alteplase in 360 patients with stroke (119 women, 71 ± 11 years old). The outcomes were symptomatic intracerebral hemorrhage within 36 hours and independence at 3 months defined by a modified Rankin Scale score of 0 to 2.

RESULTS

DWI-ASPECTS was positively correlated with CT-ASPECTS (ρ=0.511, P<0.001) and was lower than CT-ASPECTS (median 8 [interquartile range, 6 to 9] versus 9 [8 to 10], P<0.001). Higher baseline National Institutes of Health Stroke Scale score (standardized partial regression coefficient [β] 0.061, P<0.001) and cardioembolic stroke (β 0.35, P<0.001) were related to this discrepancy. The area under the receiver operating characteristic curve for predicting sICH (12 patients) using ASPECTS was 0.673 (95% CI, 0.503 to 0.807) by CT and 0.764 (95% CI, 0.635 to 0.858) by DWI (P=0.275). The area for predicting independence at 3 months (192 patients) was 0.621 (0.564 to 0.674) by CT and 0.639 (0.580 to 0.694) by DWI (P=0.535).

CONCLUSIONS

For patients with hyperacute stroke, DWI-ASPECTS scored approximately 1 point lower than CT-ASPECTS. Both CT-ASPECTS and DWI-ASPECTS were useful predictors of symptomatic intracerebral hemorrhage and independence at 3 months after recombinant tissue-type plasminogen activator.

Residual vessel length on magnetic resonance angiography identifies poor responders to alteplase in acute middle cerebral artery occlusion patients: exploratory analysis of the Japan Alteplase Clinical Trial II

BACKGROUND AND PURPOSE

It remains unknown whether the effects of 0.6 mg/kg alteplase differ with occlusion site of the middle cerebral artery (MCA). We therefore evaluated the effects of 0.6 mg/kg intravenous alteplase in patients with different sites of MCA occlusion.

METHODS

An exploratory analysis was made of 57 patients enrolled in the Japan Alteplase Clinical Trial II (J-ACT II), originally designed to evaluate 0.6 mg/kg alteplase in Japanese patients with unilateral occlusion of the MCA (M1 or M2 portion). The residual vessel length (in mm), determined by pretreatment magnetic resonance angiography, was used to reflect the occluded site. The proportions of patients with valid recanalization (modified Mori grade 2 to 3) at 6 and 24 hours and a modified Rankin Scale (mRS) score of 0 to 1 and of 0 to 2 at 3 months were compared between the groups dichotomized according to length of the residual vessel. Multiple logistic-regression models were generated to elucidate the predictors of valid recanalization, mRS 0 to 1, and mRS 0 to 2.

RESULTS

Receiver operating characteristics analysis revealed that 5 mm was the practical cutoff length for dichotomization. In patients with an M1 length < 5 mm (n = 12), the frequencies of valid recanalization at 6 and 24 hours (16.7% and 25.0%) were significantly lower compared with those (62.1% and 82.8%, respectively) of the 45 patients with a residual M1 length ≥ 5 mm and an M2 occlusion (P = 0.008 for 6 hours, P < 0.001 for 24 hours). The proportions of patients who achieved an mRS of 0 to 1 and an mRS of 0 to 2 were also lower for those with an M1 length < 5 mm (8.3% and 16.7%, respectively) compared with the other group (57.8% and 68.9%, respectively; P = 0.003 for mRS 0 to 1, P = 0.002 for mRS 0 to 2). In logistic-regression models, the site of MCA occlusion (< 5 mm) was a significant predictor of valid recanalization at 6 and 24 hours and of an mRS of 0 to 1 and of mRS of 0 to 2.

CONCLUSIONS

In patients with acute MCA occlusion, a residual vessel length < 5 mm on magnetic resonance angiography can identify poor responders to 0.6 mg/kg alteplase. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00412867.

Routine Use of Intravenous Low-Dose Recombinant Tissue Plasminogen Activator in Japanese Patients

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.