BACKGROUND: Although a phase 3 trial using cardiac dose of the GP IIb/IIIa inhibitor abciximab was halted, we previously reported that a 30% lower total intravenous (IV) abciximab dose achieved optimal platelet inhibition (92%) and showed benefit in patients ineligible for tPA when compared using a rigorous matching process to historical controls (Mandava et al, TSR 2010). Given lack of proven alternatives, we were interested in abciximab specifically in the posterior circulation.
METHODS: 0.2 mg/kg IV bolus followed by 0.05 ug/kg/hr infusion over 12 hrs of abciximab was administered with suspected large vessel posterior circulation occlusion after informed consent and presentation of alternatives. Patients were ineligible for tPA mostly from time window (24 hrs, later changed to 12 hrs) or elevated INR < 2.5. A weight based heparin protocol was used in most patients to achieve PTT 46-70. Ninety day follow up was obtained. To assess benefit, patients baseline characteristics were compared to the NINDS control arms subjects restricted to large vessel and cardioembolic subtypes. Matching was performed for 5 hour baseline NINDS NIHSS, age, glucose, and posterior stroke. An excess of posterior strokes in the abciximab group permitted 2:1 matching with outlier elimination. McNemars test compared 90 day mRS 0-1/0-2, mortality, and hemorrhage
RESULTS: 26 subjects were treated in 3 university centers. Post-match baseline variables were slightly more severe in the abciximab group and they were treated later (Table). 90-day functional outcomes were higher in the abciximab group (mRS 0-1:54.5% vs 23.1%, mRS 0-2: 63.6% vs 30.8%; p<0.008). Non-significant higher mortality was seen in the NINDS group while symptomatic hemorrhage rate was non-significantly higher after abciximab.
CONCLUSION: Low dose IV abciximab in extended time window for large vessel posterior stroke shows promise. Given lack of proven alternatives, these results need to be verified prospectively.