[Clinical study of therapeutic time window of local fibrinolysis for acute middle cerebral artery occlusion].

We evaluated the efficacy of local intra-arterial fibrinolysis (LIF) used in tissue plasminogen activator (t-PA) and its indication for acute middle cerebral artery (MCA) occlusion on angiographic degree of leptomeningeal collateral flow in a series of 26 patients (mean age: 67.2 years old). The occlusion types were classified into three types: (1) M 1 proximal occlusion (N = 8) involved the lenticulostriate arteries (LSA), (2) M 1 distal occlusion (N = 6) without involvement of the LSA to M 2 bifurcation, (3) M 2-3 occlusion (N = 12). In M 1 proximal and distal type, 100% patients had complete or partial recanalization till 5.3 and 6 hours, and 91.7% recanalized in M 2-3 type within 3.96 hours from attack on the average. Small cerebral infarction post LIF showed in 50%, but had no clinical change for the worse in all types. There was 65% in excellent or good prognosis on 2 months after attack. Within the range of 600,000-2,400,000 units of t-PA (mean = 1,107,000 units), small hemorrhagic transformation were developed in 5 cases (19.2%) without influence on its outcome. It means that below 2,400,000 units t-PA for LIF were safety amounts. In patients with poor collateral flow in angiographic findings, good prognosis could be possible in 75% within 4 hours (M = 3.96 hours) recanalization on the average. We conclude that LIF used in t-PA would be efficatious in M 1 proximal occlusion within 4 hours of onset and in patients with poor collateral flow when recanalized within 4 hours after attack.