EFFECTS OF RECANALIZATION AND COLLATERAL BLOOD-SUPPLY ON INFARCT EXTENT AND BRAIN EDEMA AFTER MIDDLE CEREBRAL-ARTERY OCCLUSION

A series of 53 patients with angiographically proven middle cerebral artery (MCA) trunk occlusions treated with intravenous (in 46) or intra-arterial (in 7) recombinant tissue plasminogen activator (rt-PA) and heparin anticoagulation was studied with serial computed tomography to find out whether recanalization promotes ischemic brain edema and hemorrhagic transformation. Partial or complete recanalization of the MCA trunk was shown in 11 patients immediately after rt-PA treatment by a second angiogram and in altogether 18 patients 1 day later by transcranial Doppler ultrasound or a third angiogram. During follow-up the extent of hypodensity increased in 5 of 18 patients (28%) with reperfusion at 24 h after symptom onset and in 23 of 35 patients (66%) without reperfusion (p < 0.01). The ischemic edema caused a midline shift in 1 of 18 patients (6%) with reperfusion at 24 h after symptom onset, but in 14 of 35 patients (40%) without reperfusion (p < 0.05). Hemorrhagic transformation was associated with reperfusion at 24 h in 7 (39%) patients and occurred in 13 (37%) patients without reperfusion (p > 0.5). Our data suggest that recanalization of MCA trunk occlusion within 24 h after symptom onset does not promote edema or hemorrhagic transformation of ischemic brain tissue.