The INterventional Stroke Therapy Outcomes Registry (INSTOR)1 was commissioned over a decade ago at the specific request of the American Society of Interventional and Therapeutic Neuroradiology (now the Society of NeuroInterventional Surgery (SNIS)) and the American Academy of Neurology (AAN) Interventional Stroke Task Force, in order to answer questions concerning intra-arterial (IA) fibrinolysis. INSTOR is now an automatic error detecting, risk adjusting, HIPAA compliant (Health Insurance Portability and Accountability Act), computerized, web based registry that tracks intra-hospital processes, patient demographic, and procedural risk factors, as well as angiographic and clinical outcomes for both intravenous (IV) tissue plasminogen activator (tPA) and endovascular stroke interventions. This is the story of its birth, evolution, and current goals.

In 1998, Prolyse in Acute Cerebral Thromboembolism II (PROACT II) was reported as the first prospective randomized trial using endovascular techniques for the treatment of acute ischemic stroke.2 PROACT II was a phase III statistically positive trial that demonstrated 15% absolute and 60% relative benefit in functional outcomes in treated subjects, the greatest absolute benefit in clinical outcomes of any stroke trial ever performed. Indeed, PROACT II was so powerfully positive that the large numbers necessary to show benefit in the National Institute of Neurological Disorders and Stroke (NINDS) IV tPA stroke trial were not needed due to the strength of clinical benefit.3 It was anticipated that these results would usher in a new era of stroke treatment and growth of our new neurointerventional specialty.

After the publication of PROACT II, I was approached by Mike Morrison, the head of the Abbott Laboratories stroke division, to create a nationwide training program to begin the process of expanding and advancing endovascular stroke care. We decided to create several regional didactic training centers (about 5–7) with the final 1.5 day hands on training to be …