Does intravenous rtPA benefit patients in the absence of CT angiographically visible intracranial occlusion?
BACKGROUND
In patients with acute stroke receiving intravenous tissue plasminogen activator (tPA), we postulated that the presence of intracranial occlusion on CT angiography (CTA) modifies the benefit of thrombolysis.


METHODS
Using a retrospective cohort design, we identified patients with acute ischemic stroke in our CTA database between May 2002 and August 2007. All the patients had a CTA within 12 h of onset, a premorbid modified Rankin scale (mRS) < or = 1, and a baseline National Institute of Health Stroke Scale score(NIHSS)f > or = 6. The primary outcome was early effectiveness of tPA defined as an NIHSS score of < or = 2 at 24 h or a 4-point NIHSS improvement at 24 h. Secondary outcome included mRS < or = 1 at 90 days. The relationship between intracranial occlusion on CTA and benefit of tPA was assessed using a test for interaction.


RESULTS
A total of 287 patients met the criteria [occlusion present N =168; (98 with tPA; 70 without tPA) and occlusion absent N = 119; (52 with tPA; 67 without tPA)]. Those with intracranial occlusion were likely to have more severe strokes (NIHSS > or = 15; P < 0.001) and abnormal brain imaging (ASPECTS < or =7; P < 0.001). For outcome of 4-point NIHSS score improvement at 24 h, benefit from tPA was observed only among patients with a visible occlusion (absolute difference in favor of tPA: 20.4% vs. 0.7%; P = 0.06).


CONCLUSIONS
In patients with acute ischemic stroke, thrombolysis produced a better early clinical response among patients with intracranial occlusion, which needs to be confirmed in stroke thrombolysis trials.
Department of Clinical Neurosciences, Calgary Stroke Program, Calgary, Alberta, Canada. sylajapn@hotmail.com
P N
PN
Sylaja
Imanuel
I
Dzialowski
Volker
V
Puetz
Michael
M
Eliasziw
Michael D
MD
Hill
Andrea
A
Krol
Christine
C
O'Reilly
Andrew M
AM
Demchuk
D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods*; D016009:Chi-Square Distribution; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D008297:Male; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020521:Stroke / Q000175:diagnosis* / Q000188:drug therapy*; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D014057:Tomography, X-Ray Computed / Q000379:methods*
D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator