Does current oral antiplatelet agent or subtherapeutic anticoagulation use have an effect on tissue-plasminogen-activator-mediated recanalization rate in patients with acute ischemic stroke?

Abstract

Objective: Our goal is to assess if current antiplatelet (AP) use has an effect on recanalization rate and outcome in acute stroke patients.

Methods: We conducted a retrospective analysis of acute stroke patients who received intravenous (IV) recombinant tissue plasminogen activator (rt-PA) and had transcranial Doppler examination within 3 h of symptom onset. The TCD findings were interpreted using the Thrombolysis in Brain Ischemia flow grading system as persistent arterial occlusion, reocclusion or complete recanalization. Complete recanalization was defined as established Thrombolysis in Brain Ischemia 4 or 5 within 2 h of IV rt-PA. The patients were divided based on their current use of AP agents. Comparisons were made between the different groups based on recanalziation rate, reocclusion and good long-term outcome (mRS ≤ 2) using χ(2) test. Multiple regression analysis was used to identify AP use as a predictor for recanalization and outcome including symptomatic intracranial hemorrhage after controlling for age, baseline NIHSS score, time to treatment, previous vascular event, hypertension and diabetes mellitus.

Results: Two hundred and eighty-four patients were included; 154 (54%) males, 130 (46%) females, with a mean age of 69.5 ± 13 years. The median baseline NIHSS score was 16 ± 5. The median time to TCD examination was 131 ± 38 min from symptom onset. The median time to IV rt-PA was 140 ± 34 min. One hundred eighty patients were not on AP prior to their stroke, 76 were on aspirin, 15 were on clopidogrel, 2 were on aspirin-dipyridamole combination, 2 were on both aspirin and clopidogrel, and 9 patients on subtherapeutic coumadin. In patients who were naïve to AP, 68/178 (38.2%) had complete recanalization, whereas in the AP group, 25/91 (28%) had complete recanalization. Patients on aspirin alone had a lower recanalization rate (16/72) as compared to those not on AP (22 vs. 39%) (p = 0.017), while those on clopidogrel had higher rates of complete recanalization (9/19, 60%). There was no difference in the rate of symptomatic intracranial hemorrhages in patients on AP agents as compared to those not on AP (9/180, 5% vs. 9/95, 9.5%) (p = 0.13). A good long-term outcome (mRS ≤2) was achieved in 85/160 (53%) of the patients naïve to AP and in 33/84 (39%) of the patients on AP (p = 0.035). In multiple regression, AP use was not a predictor of either recanalization rate (p = 0.057) or good outcome (p = 0.27).

Conclusions: No correlation was found between AP use and recanalization rate and good outcome in patients with acute stroke who received IV rt-PA treatment. Prior AP use should not defer patients from receiving IV rt-PA treatment in an acute stroke setting.