Complete recanalization via fibrinolytic therapy can reduce the number of ischemic territories that progress to infarction.
OBJECTIVE
To clarify the clinical significance of fibrinolytic therapy for acute ischemic stroke.


METHODS
We analyzed findings in 18 patients with occlusion of a major artery in respect to cerebral blood flow thresholds for infarction. Nine of these patients had shown complete recanalization just after the treatment, between 3.5 and 7.25 hours after symptom onset, and the other nine had shown no change. Cerebral blood flow was measured by single-photon emission CT using 99mTC-labeled hemamethylpropyleneamine oxime and assessed semiquantitatively: multiple regions of interest were placed on the section images and two parameters, the R/CL ratio and the R/CE ratio, were calculated (where R represents a mean count of the region of interest in the affected hemisphere, CL on the opposite side, and CE in the cerebellar hemisphere on the affected ischemic side).


RESULTS
Reperfusion significantly reduced the development of infarction in the regions of interest with an R/CL ratio between 0.65 and 0.85 or an R/CE ratio between 0.55 and 0.75. No correlation was observed between the development of infarction and the duration of ischemia. The cerebral blood flow threshold in patients without recanalization was higher than that in patients with recanalization.


CONCLUSIONS
Reperfusion achieved by fibrinolytic therapy in the acute stage can save ischemic brain within a limited cerebral blood flow value.
Sasaki
O
O
Department of Neurosurgery, Nigata City General Hospital, Japan.
Takeuchi
S
S
Koizumi
T
T
Koike
T
T
Tanaka
R
R
D000368:Aged; D001921:Brain / Q000098:blood supply; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000188:drug therapy*; D002544:Cerebral Infarction / Q000000981:diagnostic imaging / Q000188:drug therapy*; D004292:Dominance, Cerebral / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000000981:diagnostic imaging / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D010091:Oximes; D012039:Regional Blood Flow / Q000187:drug effects; D019690:Technetium Tc 99m Exametazime; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage; D015899:Tomography, Emission-Computed, Single-Photon; D014568:Urokinase-Type Plasminogen Activator / Q000008:administration & dosage
D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator