TIA has been accepted as a concept of transient cerebral ischemia. There is an ever enlarging body of literature sparking controversies considering its natu ral history, prognosis, outcomes of clinical trials and usefulness of the concept. Much of the controversy is related to the diverse pathophysiology of TIAs, the selection of patients for clinical trials and the associated risk factor in the stud ied population.
The advantages of the concept are (1) a warning of the possibility of future irreversible pathology (2) an opportunity to treat and/or remove risk factors (3) an opportunity to establish a basis for monitoring the patient and making in terim decisions concerning intervention.
The risks of the concept are: (1) administering a specific therapy to all pa tients (2 failure to fully evaluate the patient once the diagnosis is made (3) ten dency to rely on "experts" for guidance.
TIA is a useful concept if one recognizes:
(1) the pathophysiology is polymorphous and multiplex,
(2) the concept is a signal for diligent search for the underlying cause or causes,
(3) it is more important to treat the risk factors than to give a specific ther apy.