Outcomes after stroke thrombolysis according to prior antiplatelet use

Background: Thirty percent of ischemic stroke (IS) patients suffering from acute stroke are under antiplatelet therapy.

Aims: We evaluated whether prior antiplatelet use before intravenous (IV), intra-arterial (IA) or combined IV/IA therapy may be associated with worse outcomes and an increased intracerebral hemorrhage (ICH) risk after reperfusion therapies.

Methods: We analyzed data from our patient registry (n = 874) and conducted a systematic review of previous observational studies. The primary outcome was the percentage of patients who developed symptomatic ICH (sICH), defined in our registry per ECASS-II definition.

Results: We identified 43 previous reports that evaluated the impact of prior antiplatelet use on outcomes after reperfusion therapy in AIS patients. Prior antiplatelet use was found in 35% of AIS patients, eligible for reperfusion therapies and was associated with a worse vascular profile. In an unadjusted meta-analysis that included our registry data, prior antiplatelet use was associated with more sICH per ECASS-II definition (OR, 1.78 (95% CI, 1.48-2.13), and less favorable outcome (OR, 0.86; 95% CI, 0.77-0.98). However, in multivariate analyses conducted in our registry showed that prior antiplatelet use was not associated with worse outcome (P > 0.23); and in the systematic review, only 3 studies reported a slight, but significant adjusted increase in sICH risk, of whom one had conflicting results according to sICH definition.

Conclusions: These results suggest no significant detrimental effect of prior antiplatelet use in AIS patients treated by IV, IA or combined IV/IA therapy. Further studies are needed to assess the specific impact of different and cumulative antiplatelet agents.