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Combination therapy with normobaric oxygen (NBO) plus thrombolysis in experimental ischemic stroke.

ABSTRACT: The widespread use of tissue plasminogen activator (tPA), the only FDA-approved acute stroke treatment, remains limited by its narrow therapeutic time window and related risks of brain hemorrhage. Normobaric oxygen therapy (NBO) may be a useful physiological strategy that slows down the process of cerebral infarction, thus potentially allowing for delayed or more effective thrombolysis. In this study we investigated the effects of NBO started simultaneously with intravenous tPA, in spontaneously hypertensive rats subjected to embolic middle cerebral artery (MCA) stroke. After homologous clot injection, animals were randomized into different treatment groups: saline injected at 1 hour; tPA at 1 hour; saline at 1 hour plus NBO; tPA at 1 hour plus NBO. NBO was maintained for 3 hours. Infarct volume, brain swelling and hemorrhagic transformation were quantified at 24 hours. Outcome assessments were blinded to therapy.Upon clot injection, cerebral perfusion in the MCA territory dropped below 20% of pre-ischemic baselines. Both tPA-treated groups showed effective thrombolysis (perfusion restored to nearly 100%) and smaller infarct volumes (379 +/- 57 mm3 saline controls; 309 +/- 58 mm3 NBO; 201 +/- 78 mm3 tPA; 138 +/- 30 mm3 tPA plus NBO), showing that tPA-induced reperfusion salvages ischemic tissue and that NBO does not significantly alter this neuroprotective effect. NBO had no significant effect on hemorrhagic conversion, brain swelling, or mortality.NBO can be safely co-administered with tPA. The efficacy of tPA thrombolysis is not affected and there is no induction of brain hemorrhage or edema. These experimental results require clinical confirmation.

SUBMITTER: Fujiwara N

PROVIDER: S-EPMC2714858 | biostudies-other | 2009 Jul

REPOSITORIES: biostudies-other

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Combination therapy with normobaric oxygen (NBO) plus thrombolysis in experimental ischemic stroke.

Fujiwara Norio N Murata Yoshihiro Y Arai Ken K Egi Yasuhiro Y Lu Jie J Wu Ona O Singhal Aneesh B AB Lo Eng H EH

BMC neuroscience 20090715

<h4>Background</h4>The widespread use of tissue plasminogen activator (tPA), the only FDA-approved acute stroke treatment, remains limited by its narrow therapeutic time window and related risks of brain hemorrhage. Normobaric oxygen therapy (NBO) may be a useful physiological strategy that slows down the process of cerebral infarction, thus potentially allowing for delayed or more effective thrombolysis. In this study we investigated the effects of NBO started simultaneously with intravenous tP ...[more]

PMID: 19604385

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Project description:BackgroundThrombolysis with intravenous rt-PA is currently the only approved acute therapy for ischemic stroke. Re-occlusion after initial recanalization occurs in up to 34% in patients treated with rt-PA, probably caused by platelet activation. In acute myocardial infarction, the combination of thrombolysis and antiplatelet therapy leads to a greater reduction of mortality compared to thrombolysis alone. In patients with acute ischemic stroke, several studies showed that patients already on antiplatelet treatment prior to thrombolysis had an equal or even better outcome compared to patients without prior antiplatelet treatment, despite an increased risk of intracerebral bleeding. Based on the fear of intracerebral haemorrhage, current international guidelines recommend postponing antiplatelet therapy until 24 hours after thrombolysis. Remarkably, prior use of antiplatelet therapy is not a contra-indication for thrombolysis. We hypothesize that antiplatelet therapy in combination with rt-PA thrombolysis will improve outcome by enhancing fibrinolysis and preventing re-occlusion.Methods/designARTIS is a randomised multi-center controlled trial with blind endpoint assessment. Our objective is to investigate whether immediate addition of aspirin to rt-PA thrombolysis improves functional outcome in ischemic stroke. Patients with acute ischemic stroke eligible for rt-PA thrombolysis are randomised to receive 300 mg aspirin within 1.5 hours after start of thrombolysis or standard care, consisting of antiplatelet therapy after 24 hours. Primary outcome is poor functional health at 3 months follow-up (modified Rankin Scale 3 - 6).DiscussionThis is the first clinical trial investigating the combination of rt-PA and acute aspirin by means of a simple and cheap adjustment of current antiplatelet regimen. We expect the net benefit of improved functional outcome will overcome the possible slightly increased risk of intracerebral haemorrhage.Trial registrationThe Netherlands National Trial Register NTR822. The condensed rationale of the ARTIS-Trial has already been published in Cerebrovascular Diseases.

Project description:IntroductionIn patients with stroke attributable to cervical artery dissection, we compared endovascular therapy to intravenous thrombolysis regarding three-month outcome, recanalisation and complications.Materials and methodsIn a multicentre intravenous thrombolysis/endovascular therapy-register-based cohort study, all consecutive cervical artery dissection patients with intracranial artery occlusion treated within 6?h were eligible for analysis. Endovascular therapy patients (with or without prior intravenous thrombolysis) were compared to intravenous thrombolysis patients regarding (i) excellent three-month outcome (modified Rankin Scale score 0-1), (ii) symptomatic intracranial haemorrhage, (iii) recanalisation of the occluded intracranial artery and (iv) death. Upon a systematic literature review, we performed a meta-analysis comparing endovascular therapy to intravenous thrombolysis in cervical artery dissection patients regarding three-month outcome using a random-effects Mantel-Haenszel model.ResultsAmong 62 cervical artery dissection patients (median age 48.8 years), 24 received intravenous thrombolysis and 38 received endovascular therapy. Excellent three-month outcome occurred in 23.7% endovascular therapy and 20.8% with intravenous thrombolysis patients. Symptomatic intracranial haemorrhage occurred solely among endovascular therapy patients (5/38 patients, 13.2%) while four (80%) of these patients had bridging therapy; 6/38 endovascular therapy and 0/24 intravenous thrombolysis patients died. Four of these 6 endovascular therapy patients had bridging therapy. Recanalisation was achieved in 84.2% endovascular therapy patients and 66.7% intravenous thrombolysis patients (odds ratio 3.2, 95% confidence interval [0.9-11.38]). Sensitivity analyses in a subgroup treated within 4.5?h revealed a higher recanalisation rate among endovascular therapy patients (odds ratio 3.87, 95% confidence interval [1.00-14.95]), but no change in the key clinical findings. In a meta-analysis across eight studies (n?=?212 patients), cervical artery dissection patients (110 intravenous thrombolysis and 102 endovascular therapy) showed identical odds for favourable outcome (odds ratio 0.97, 95% confidence interval [0.38-2.44]) among endovascular therapy patients and intravenous thrombolysis patients.Discussion and conclusionIn this cohort study, there was no clear signal of superiority of endovascular therapy over intravenous thrombolysis in cervical artery dissection patients, which - given the limitation of our sample size - does not prove that endovascular therapy in these patients cannot be superior in future studies. The observation that symptomatic intracranial haemorrhage and deaths in the endovascular therapy group occurred predominantly in bridging patients requires further investigation.

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Combination therapy with normobaric oxygen (NBO) plus thrombolysis in experimental ischemic stroke.

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Combination therapy with normobaric oxygen (NBO) plus thrombolysis in experimental ischemic stroke.

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