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

The Impact of Loading Dose on Outcome in Stroke Patients Receiving Low-Dose Tissue Plasminogen Activator Thrombolytic Therapy

Background

Intravenous tissue plasminogen activator (tPA) (0.9 mg/kg, maximum 90 mg) with a bolus of 10% of the total dose given within 1–2 mins is the standard therapy for patients receiving thrombolytic therapy. Low-dose (0.6 mg/kg) tPA is also approved for thrombolytic therapy for ischemic stroke patients. Low-dose tPA is associated with a low bolus dose. It is unknown whether increasing the bolus dose in patients receiving low-dose tPA thrombolysis may improve outcomes or increase the risk of hemorrhagic transformation (HT).

Aim

This study investigated the impact of the bolus dose on the outcome in ischemic stroke patients receiving low-dose tPA thrombolytic therapy.

Methods

In this retrospective, observational study, we enrolled 214 ischemic stroke patients receiving low-dose tPA thrombolytic therapy. Of these 214 patients, 107 patients received 10% of the total dose as a bolus dose, and 107 patients received 15% of the total dose as a bolus dose. The National Institutes of Health Stroke Score (NIHSS) were evaluated before tPA infusion, 24 h after thrombolytic therapy, and at discharge. Stroke severity was categorized as mild (0–5), moderate (6–14), severe (15–24), or very severe (≥25). Neurological improvement (NI) was defined as an improvement of 6 or more points in the NIHSS, and no response (NR) was defined as an increase in the NIHSS of ≤4 points or a decrease ≤6 points. Neurological deterioration (ND) was defined as an increase in the NIHSS >4 points. A good outcome was defined as a modified Ranking Score (mRS) of 0 or 1. We compared the NI, NR, and ND rates at 24 hrs after thrombolytic therapy and discharge between the 15% and 10% bolus dose groups.

Results

In patients with mild and moderate stroke, there was no significant difference in the NI, NR, ND, and HT rates and 6-month outcomes between the 15% and 10% bolus groups. In patients with severe and very severe stroke, outcomes at 6 months were significantly better in the 15% bolus group than in the 10% bolus group. The factors affecting the outcomes of severe and very severe stroke patients are hypertension and bolus dose.

Conclusion

In severe and very severe stroke patients receiving low-dose tPA thrombolytic therapy, a bolus dose of 15% of the total dose can improve outcomes.

Posterior circulation ischemic stroke-a review part II: imaging and acute treatment

Posterior circulation strokes affect the vertebrobasilar arterial system, account for about 20-25% of all ischemic strokes, and are a significant cause of patient disability and mortality. Diagnosis can be challenging; clinical presentation and common pitfalls facing posterior circulation stroke have been discussed elsewhere. In the first part of the review, we focus on the imaging, discussing the information that can be gathered through a correct selection and interpretation of different possible studies helping to achieve an early diagnosis and to select the best medical treatment. In the second part of the review, we will discuss the best therapeutic treatments available at the moment for posterior circulation ischemia.

Outcome of stroke patients receiving different doses of recombinant tissue plasminogen activator

Background and purpose

Intravenous recombinant tissue plasminogen activator (tPA) at a dose of 0.9 mg/kg body weight is associated with a high hemorrhagic transformation (HT) rate. Low-dose tPA (0.6 mg/kg) may have a lower hemorrhage rate but the mortality and disability rates at 90 days cannot be confirmed as non-inferior to standard-dose tPA. Whether the doses 0.7 and 0.8 mg/kg have better efficacy and safety needs further investigation. Therefore, this study is to compare the efficacy and safety of each dose of tPA (0.6, 0.7, 0.8, and 0.9 mg/kg body weight) and to investigate the factors affecting early neurological improvement (ENI) and early neurological deterioration (END).

Methods

For this observational study, data were obtained from 274 patients who received tPA thrombolytic therapy in Chia-Yi Christian Hospital stroke unit. The tPA dose was given at the discretion of each physician. The definition of ENI was a >8 point improvement (compared with baseline) at 24 h following thrombolytic therapy or an improvement in the National Institutes of Health Stroke Score (NIHSS) to 0 or 1 toward the end of tPA infusion. The definition of END was a >4 point increase in NIHSS (compared with baseline) within 24 h of tPA infusion. The primary objective was to investigate whether 0.7 and 0.8 mg/kg of tPA have higher ENI rate, lower END rate, and better outcome at 6 months. Poor outcome was defined as having a modified Rankin Scale of 3 to 6 (range, 0 [no symptoms] to 6 [death]). The secondary objective was to investigate whether low-dose tPA has a lower risk of intracerebral HT than that with standard-dose tPA. We also investigated the factors affecting ENI, END, HT, and 6-month outcome.

Results

A total of 274 patients were included during the study period, of whom 260 were followed up for >6 months. There was a trend for the HT rate to increase as the dose increased (P=0.02). The symptomatic HT rate was not significantly different among the low-dose and standard-dose groups. The ENI and END (P=0.52) were not significantly different among the four dosage groups. The clinical functional outcome at 6 months after stroke onset was poorer in the standard-dose group (P=0.02). Stroke severity (P<0.01), stroke type (P=0.03), and diabetes mellitus (P=0.04) affected the functional outcome at 6 months.

Conclusion

Among the 274 patients receiving tPA thrombolytic therapy, the HT rate increased as dose increased. The symptomatic HT, ENI and END rates were not significantly different among the low-dose (0.6, 0.7, and 0.8 mg/kg) and standard-dose groups. Stroke severity (NIHSS >12), stroke type (cardioembolism and large artery atherosclerosis) and diabetes mellitus were associated with poor outcome at 6 months.

A novel route of revascularization in basilar artery occlusion and review of the literature

Ischemia of the basilar artery is one of the most devastating types of arterial occlusive disease. Despite treatment of basilar artery occlusions (BAO) with intravenous tissue plasminogen activator, antiplatelet agents, intra-arterial therapy or a combination, fatality rates remain high. Aggressive recanalization with mechanical thrombectomy is therefore often necessary to preserve life. When direct access to the basilar trunk is not possible, exploration of chronically occluded vessels through collaterals with angioplasty and stenting creates access for manual aspiration. We describe the first report of retrograde vertebral artery (VA) revascularization using thyrocervical collaterals for anterograde mechanical aspiration of a BAO followed by stenting of the chronically occluded VA origin. Our novel retrograde-anterograde approach resulted in resolution of the patient's clinical stroke syndrome.

A novel route of revascularization in basilar artery occlusion and review of the literature

Ischemia of the basilar artery is one of the most devastating types of arterial occlusive disease. Despite treatment of basilar artery occlusions (BAO) with intravenous tissue plasminogen activator, antiplatelet agents, intra-arterial therapy or a combination, fatality rates remain high. Aggressive recanalization with mechanical thrombectomy is therefore often necessary to preserve life. When direct access to the basilar trunk is not possible, exploration of chronically occluded vessels through collaterals with angioplasty and stenting creates access for manual aspiration. We describe the first report of retrograde vertebral artery (VA) revascularization using thyrocervical collaterals for anterograde mechanical aspiration of a BAO followed by stenting of the chronically occluded VA origin. Our novel retrograde-anterograde approach resulted in resolution of the patient's clinical stroke syndrome.

Ischemic posterior circulation stroke: a review of anatomy, clinical presentations, diagnosis, and current management

Posterior circulation strokes represent approximately 20% of all ischemic strokes (1, 2). In contrast to the anterior circulation, several differences in presenting symptoms, clinical evaluation, diagnostic testing, and management strategy exist presenting a challenge to the treating physician. This review will discuss the anatomical, etiological, and clinical classification of PC strokes, identify diagnostic pitfalls, and overview current therapeutic regimens.