Early Recanalization Rate of Major Occluded Brain Arteries after Intravenous Tissue Plasminogen Activator Therapy Using Serial Magnetic Resonance Angiography Studies

PURPOSE: The present study investigated early recanalization rate of major occluded arteries after tissue plasminogen activator (t-PA) infusion using serial magnetic resonance angiography (MRA) studies. METHODS: Consecutive stroke patients treated with t-PA within 3 h of onset were prospectively studied. Four serial MRA studies were conducted: before, immediately, 24 h and 5-7 days after t-PA infusion. RESULTS: Initial MRA demonstrated occluded brain arteries in 64 patients: M1 occlusion, 30 patients; M2, 12, and internal carotid artery (ICA), 22. Combining M1 and M2 occlusion, the recanalization rates (complete and partial) were 52.3% (19.0 and 33.3%) within 1 h, 80.9% (47.6 and 33.3%) at 24 h and 87.8% (73.2 and 14.6%) 7 days after t-PA infusion. However, the recanalization rate of ICA occlusion was 31.8% (4.5 and 27.3%) within 1 h, 51.1% (14.3 and 47.6%) at 24 h and 66.7% (38.9 and 27.8%) 7 days after t-PA infusion. Complete recanalization rate at 24 h and 7 days was lower in ICA occlusion than M1 and M2 occlusion (p = 0.014 and p = 0.016). CONCLUSION: Within 1 h after t-PA infusion, approximately half the patients with major arteries occlusion had early recanalization. ICA occlusion is resistant to intravenous t-PA therapy compared with middle cerebral artery occlusion.