TPA: Within 180 Minutes
The National Institute of Neurological Disorders and Stroke Recombinant Tissue Plasminogen Activator (NINDS rt-PA) Stroke Study, a multicenter, randomized trial, has demonstrated the efficacy of treatment with intravenous rt-PA (alteplase) started within 3 hours after the onset of symptoms. Pooled analysis of six randomized trials has suggested a potential benefit within up to 6 hours after the onset of stroke. Trials assessing treatment in this extended time frame among broad populations of patients with ischemic stroke are underway.
Given concerns about adverse effects of the short-term lowering of blood pressure on cerebral perfusion just after an ischemic stroke, current guidelines based on consensus opinion recommend withholding antihypertensive therapy during the active phase of ischemic stroke unless the diastolic blood pressure exceeds 120 mm Hg or the systolic blood pressure exceeds 220 mm Hg in patients who are not candidates for rt-PA. In contrast, blood pressure monitoring is recommended before, during, and after rt-PA therapy, and intravenous antihypertensive therapy is recommended to maintain the systolic blood pressure below 180 mm Hg and the diastolic below 105 mm Hg.
CT versus MRI for Stroke
CT has high sensitivity for acute intracranial hemorrhage, but MRI has a much higher sensitivity than CT for acute ischemic changes, especially those in the posterior fossa and in the first hours after an ischemic stroke. Edema due to cytotoxicity is detectable within minutes after the onset of ischemia, with a reduced apparent diffusion coefficient on diffusion-weighted imaging. However, it remains unclear whether early visualization of ischemia has important implications for management.
Questions
Q: What are the contraindications to intravenous thrombolysis in patients with acute ischemic stroke?
A: Among the major contraindications to thrombolysis in patients with an acute ischemic stroke are onset of symptoms more than 3 hours before the start of treatment, intracranial hemorrhage on CT or MRI, head trauma or stroke in previous 3 months, myocardial infarction in the previous 3 months, major surgery in the previous 14 days, history of intracranial hemorrhage, systolic blood pressure equal to or greater than 185 mm Hg or diastolic blood pressure equal to or greater than 110 mm Hg, and other contraindications listed in the table below.
Questions
Q: What are the contraindications to intravenous thrombolysis in patients with acute ischemic stroke?
A: Among the major contraindications to thrombolysis in patients with an acute ischemic stroke are onset of symptoms more than 3 hours before the start of treatment, intracranial hemorrhage on CT or MRI, head trauma or stroke in previous 3 months, myocardial infarction in the previous 3 months, major surgery in the previous 14 days, history of intracranial hemorrhage, systolic blood pressure equal to or greater than 185 mm Hg or diastolic blood pressure equal to or greater than 110 mm Hg, and other contraindications listed in the table below.
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