New 'Clot-Busting' Strategies Show Promise for Stroke
Include Transcranial Ultrasound, Direct Clot Disruption,
Combination IV and IA tPA
By Charles Bankhead
WebMD Medical News
Feb. 11, 2000 (New Orleans) -- New strategies for reducing infarct size and patient morbidity were presented today at the American Stroke Association's 25th annual International Stroke Conference in New Orleans. Among new techniques that showed promise for stroke were: combining thrombolytic therapy with continuous transcranial Doppler monitoring, combination IV and intra-arterial (IA) tPA administration, and a new mechanical "clot-busting" technique.
In a poster presentation at the meeting, Souvik Sen, MD, assistant professor of neurology at Seton Hall University in Edison, N.J., described the group's success with a mechanical clot disruption technique followed by intra-arterial tPA.
The investigators evaluated a strategy of mechanical clot
disruption by catheter guidewire, followed immediately by 7-30 mg of intra-arterial
tPA, in 16 stroke patients who presented 3-6 hours after symptom onset. Ten
patients had anterior occlusions, and the remaining six had posterior occlusions.
The investigators were able to reach the clot and disrupt it in 15 of 16 cases. The one failure to reach the clot involved
inability of the guidewire to cross a stenosis proximal to it, says Sen.
The technique led to recanalization in 10 of the 16 stroke patients who presented up to 6 hours after symptom onset,
and six of the 10 patients who showed recanalization also showed neurologic improvement, defined
by at least a four-point change in NIHSS score. In contrast, no patient
improved among the six who did not show recanalization. Sen notes that
tPA is currently approved for use only in patients who present within 3
hours of symptom onset.
Procedural complications consisted of two intracranial hemorrhages, of which one proved fatal.
"This procedure provides a new approach to acute ischemic stroke therapy, both anterior and posterior stroke, for patients
presenting 3-6 hours after symptom onset," says Sen. "tPA is still the treatment of choice
for patients who present within 3 hours, because it is the only approved
treatment for that time window. A trial comparing intra-arterial and intravenous tPA is
needed before we can say whether this procedure is appropriate for patients who present within 3 hours."
Sen says that alternate clinical strategies are needed for stroke patients who
present beyond the 3-hour treatment window for tPA. Recently, data have
emerged to suggest a benefit of IA pro-urokinase plus heparin for patients
who present up to 6 hours after the onset of stroke symptoms, and a number of case studies have provided evidence of a
beneficial effect of IA tPA beyond 3 hours, he says.