Transient Strokes, also known as TIA (Transient ischemic attack), mini strokes, etc, usually have no permanent brain damage. However, this is a warning to the patient to get a handle on things by going on a regiment of some type of anti-coagulant, such as ordinary Aspirin and usually is an indication of partly clogged arteries.
Most advanced strokes are frequently the result of a clot originating in the left atrial appendage, a small sack in the left side of the heart that really serves no useful cardiac purpose. Those clots cannot form if the patient is on an anticoagulant regimen, which Plavix provides, but has it's own side effects. Studies have shown that Plavix is no more effective than a single, daily adult aspirin and many internist have switched their patients to aspirin because of the reduced side effects.
The vast majority of patients that experience TIAs, if treated early and aggressively do very well and usually live normal lives, often never experiencing another episode. Hopefully, Donny is in that category.
Good luck old friend,