Two decades ago, the NINDS study showed that IV t-PA was relatively effective when treating physicians used only a CT scan and a checklist dominated by time and comorbidities to choose recipients of IV t-PA. Later studies showed that the decision to give t-PA could be made by individuals who did not have extensive neurology training or sophistication. IV t-PA was safe in these primary stroke centers even if the patient did not have a stroke, but instead had a stroke mimic.
The IST-3 studies discussed in this edition of Neurology Reviews added further information. The protocols used in these studies, which were performed predominantly in Europe and Asia, also depended on simple technology: a CT scan. Even when CT scans showed old infarcts, signs of new infarction, and hyperdense vessel signs, IV t-PA was safe, although the presence of these signs on CT did result in more important bleeding after IV t-PA than the absence of these findings. Patients with old and new infarcts had poorer outcomes than those without these findings, although t-PA still provided some benefit, as determined by a slightly larger number of patients who remained independent after treatment.
During the past decade, studies in patients who had vascular imaging showed that IV t-PA resulted at best in only 30% improvement in outcome in patients with intracranial arterial occlusions. During the past year, many treatment trials have shown that intra-arterial intervention (ie, clot retraction or intra-arterial thrombolytic administration) provided better outcomes even when IV t-PA already had been given. These trials, in contrast with the CT-scan-only studies mentioned above, required more technology and more neurology or stroke training and expertise. Patients had CT or MRI brain and vascular imaging that defined the presence, sites, and extent of intracranial arterial occlusions; the presence and quantity of tissue already infarcted; and the presence and extent of potential collateral circulation. These trials were carried out mostly in academic medical centers throughout the world that contained the necessary technology and had physicians with advanced training and experience in caring for stroke patients who provided continuous coverage.
Now there are two worlds of acute stroke management: the CT-scan only primary center world characterized by checklists and no requirement for advanced stroke training and experience, and the academic medical center world that requires advanced technology evaluation and advanced treatment capabilities. It is uncertain how these two worlds will change. Will the CT-scan-only world connect with the other world by telemedicine or rapid transfers (ie, “drip and ship”), or will many primary centers meld into high-tech centers? Will many more high-tech centers develop? Will communities and countries make it mandatory to send stroke patients to high-tech centers? If so, will these centers be able to handle the major increase in volume? Stay tuned—these are exciting times.
—Louis R. Caplan, MD
Professor of Neurology,
Harvard Medical School,
Beth Israel Deaconess Medical Center,
Boston