Is the benefit of early recanalization sustained at 3 months? A prospective cohort study

Abstract

Background and purpose: Early arterial recanalization can lead to dramatic recovery (DR) during intravenous tissue plasminogen activator (tPA) therapy. However, it remains unclear whether this clinical recovery is sustained 3 months after stroke.

Methods: We studied consecutive patients treated with intravenous tPA (0.9 mg/kg within 3 hours) who had M1 or proximal M2 middle cerebral artery occlusion on pretreatment transcranial Doppler according to previously validated criteria. Patients were continuously monitored for 2 hours after tPA bolus to determine complete, partial, or no early recanalization with the Thrombolysis in Brain Ischemia (TIBI) flow grading system. A neurologist obtained the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) scores independently of transcranial Doppler results. DR was defined as a total NIHSS score of 0 to 3 points, and early recovery (ER) was defined improvement by > or =10 points at 2 hours after tPA bolus. Good long-term outcome was defined as an NIHSS score of 0 to 2 or an mRS score of 0 to 1 at 3 months.

Results: Fifty-four patients with proximal middle cerebral artery occlusion had a median prebolus NIHSS score of 16 (range, 6 to 28; 90% with > or =10 points). The tPA bolus was given at 130+/-32 minutes (median, 120 minutes; 57% treated within the first 2 hours). DR+ER was observed in 50% of patients with early complete recanalization (n=18), 17% with partial recanalization (n=18), and 0% with no early recanalization (n=18) (P=0.025). Overall, DR+ER was observed in 12 patients (22%), and 9 (75%) had good outcome at 3 months in terms of NIHSS (P=0.009) and mRS (P=0.006) scores compared with non-DR and non-ER patients. If early recanalization was complete, 50% of these patients had good outcome at 3 months, and 78% with DR+ER sustained early clinical benefit. If recanalization was partial, 44% had good long-term outcome, and 66% of patients with DR+ER sustained the benefit. If no early recanalization occurred, 22% had good long-term outcome despite the lack of DR within 2 hours of tPA bolus (P=0.046). Mortality was 11%, 11%, and 39% in patients with complete, partial, and no early recanalization, respectively (P=0.025). Reasons for not sustaining DR in patients with early recanalization were subsequent symptomatic intracranial hemorrhage and recurrent ischemic stroke.

Conclusions: DR or ER after recanalization within 2 hours after tPA bolus was sustained at 3 months in most patients (75%) in our study. Complete or partial early recanalization leads to better outcome at 3 months after stroke. Fewer patients achieve good long-term outcome without early recanalization.