Cerebral intraarterial fibrinolysis at the crossroads: is a phase III trial advisable at this time?

PURPOSE To describe the rationale for fibrinolysis, review the state of the art in cerebral fibrinolysis, and discuss whether it is time for phase III studies of cerebral intraarterial fibrinolysis.

METHODS Critical review of the literature with statistical reevaluation of significant clinical data.

RESULTS There are abundant phase III data supporting the use of thrombolysis in the cardiovascular system. However, there are no published phase III trials of intraarterial fibrinolysis in stroke. All reports of cerebral intraarterial fibrinolysis are case series. The studies are typically small with variable treatment protocols and designs that are susceptible to bias. The only analysis comparing cerebral intraarterial fibrinolysis with conventional therapy is based on nonconcurrent controls.

CONCLUSIONS Stroke is common and costly. Acute stroke intervention with fibrinolytic drugs is theoretically justified. Studies done to date have significant, inferential limitations. The data suggest an association between thrombolysis, recanalization, and prognosis. However, imprecision and inadequate control of systematic error preclude conclusions regarding clinical outcomes. Randomized, controlled trials are needed to establish the clinical value of cerebral local intraarterial fibrinolysis. However, cerebral local intraarterial fibrinolysis availability, the cerebral local intraarterial arterial fibrinolysis learning curve, anticipated technological advances, unresolved procedural controversies, and ethical and fiscal considerations make a large phase III trial impractical and ill-advised at the present time. Additional basic research is needed to set the stage for a successful clinical trial.