Description of Treatment

Recombinant issue-type plasminogen activator (rt-PA) is a thrombolytic agent used for lysis of an occluding thrombus and restoration of circulation. More than 75% of acute strokes are a result of occlusion of cerebral or pre-cerebral vessels. The use of thrombolytic agents (soon after the onset of symptoms) to restore a lumen or channel (recanalization) in the cerebral arteries should be followed by clinical and neurological improvement. The risk of hemorrhage must be considered when administering this therapy. Although several plasminogen activators have been tested, most recent studies have focused on intravenous administration of rt-PA. The use of rt-PA for acute ischemic stroke is limited to patients with acute onset of focal neurologic symptoms in a defined vascular territory. It is estimated that 3% to 7% of the patients who are admitted to a hospital with stroke symptoms are eligible for rt-PA treatment, although development of protocols to enhance utilization of rt-PA are in progress. The FDA approved this treatment in June 1996.

Committee Conclusions

With regard to tissue-type plasminogen activator for acute ischemic stroke, the ICSI Technology Assessment Committee finds the following:

1. For select patients with a clear diagnosis of ischemic stroke, administration of intravenous rt-PA (0.9 mg/kg to a maximum of 90 mg) is effective in reducing neurologic and functional deficits if administered within three hours of the onset of symptoms. Other patient selection criteria include an age of 18 years or older, no contraindications to IV rt-PA treatment on CT scan (such as intracranial hemorrhage, sulcal edema, hemispheric swelling, or large areas of low attenuation consistent with acute infarction), and the application of inclusion and exclusion criteria proposed in the NINDS trial (NINDS rt-PA Study Group, 1995; further details are specified under the headings “Contraindications” and “Potential Uses”) (Conclusion Grade II).
   
2. The evidence supports the conclusion that in appropriately selected patients with acute ischemic stroke the potential benefits of IV rt-PA outweigh the treatment-related risk of hemorrhage.
   
3. Intravenous rt-PA for acute stroke should only be utilized if the medical care providers have expertise, or access to expertise, in making a diagnosis of stroke, evaluating computed imaging studies of the brain, controlling hypertension, and diagnosing and managing possible intracranial and systemic bleeding complications of thrombolytic therapy. Facilities and staff must be available to aggressively monitor a patient's neurologic and hemodynamic parameters in an intensive care unit or a stroke unit following administration of the agent, as outlined in the NINDS trial (NINDS rt-PA Study Group, 1995).