1. Kennedy, Maureen Shawn MA, RN
  2. Ferri, Richard S. PhD, ANP, ACRN, FAAN
  3. Sofer, Dalia

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The current standard care for stroke victims calls for the administration of tissue plasminogen activator (tPA) as soon as possible after the ischemic event, in order to break apart, or lyse, remaining thrombi. In fact, conventional wisdom holds that administration more than three hours after the onset of symptoms is pointless. In a new study in the Lancet on the use of tPA in the treatment of acute stroke, researchers examined the results of six ongoing, randomized, controlled trials of tPA to see whether there was any clinical benefit to extending the time limit beyond three hours.


The six studies reviewed involved nearly 2,800 patients from 18 countries. The results support the current belief that administering tPA soon after the onset of stroke symptoms can lower the risk of morbidity and death; patients who experienced the greatest clinical benefit received tPA within 90 minutes of the onset of symptoms. While the results suggest that extending the time limit to four and a half hours may be worthwhile, by six hours after symptom onset all clinical benefit from thrombolytic therapy is gone. Further research is needed to determine which patients will benefit most from later treatment.



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A second study, published in Archives of Neurology, sought to determine the reasons that many people who might benefit from treatment with tPA after stroke are not receiving it (one national estimate is that only 2% of patients who're eligible receive it). In an attempt to discover barriers to tPA treatment, researchers at the Cleveland Clinic Health System examined 1,923 patients treated for stroke over the course of one year. Only 15% (n = 288) arrived at the ED within the first three hours of symptom onset and were thus eligible to receive tPA. Of that 15%, treatment with tPA was contraindicated in 43% (n = 98) because of mild or rapidly resolving symptoms or conditions that posed too much risk (gastrointestinal bleeding and seizure, for example).


Of the 129 remaining patients who were eligible to receive tPA treatment, only 43% did (n = 56). A number of reasons were given for their not receiving treatment. Reasons deemed "potentially justifiable" included, among other things, a poor prognosis (n = 9) and a lack of time to complete a workup (n = 8). "Other possible" reasons given included missed diagnoses (n = 8) and physician misinterpretation of guidelines (n = 9). In 27 cases, no reason was given.


Hacke W, et al. Lancet 2004;363(9411):768-74; Katzan IL, et al. Arch Neurol 2004; 61(3):346-50.