SAN DIEGO – Many of the guideline recommendations for intra-arterial catheter-directed treatment of acute ischemic stroke that were recently endorsed by neuroradiology and interventional neurology groups should be "revisited" to hasten time to revascularization to salvage more brain tissue following stroke, according to Dr. Jeffrey L. Saver.
While the multisociety guidelines endorsed by the American Society of Neuroradiology, the Society for Neurointerventional Surgery, and other professional groups recommend a door-to-revascularization time of 210 minutes (J. Vasc. Int. Radiol. 2013;24:151-63), Dr. Saver calls for 130 minutes and says this is an attainable goal in the age of stent retrievers.
Dr. Jeffrey L. Saver
"If you wait 3 hours and 30 minutes to get arteries unclogged, most of the affected brain is dead," Dr. Saver said at the annual meeting of the American Society of Neuroradiology. "That is playing Little League, and the ischemic brain is playing Major League."
Lessons from IV TPA show the dramatic effect of time in stroke outcomes, said Dr. Saver, director of the UCLA Comprehensive Stroke Center at the University of California, Los Angeles. In a study of more than 58,000 patients seen at 1,400 Get With the Guidelines stroke hospitals, he and his colleagues found that faster onset-to-treatment, in 15-minute increments, was associated with reduced in-hospital mortality (odds ratio, 0.96, P less than .001), reduced symptomatic intracranial hemorrhage (OR 0.96, P less than .001), increased achievement of independent ambulation at discharge (OR 1.04, P less than .001), and increased discharge to home (OR 1.03, P less than .001) (JAMA 2013;309:2480-8).
"In other words, for each 1,000 patients, accelerating TPA treatment by 15 minutes resulted in 18 more patients with improved ambulation at discharge, including 8 more who will ambulate fully independently, 13 more who will be discharged to a more independent environment, and 4 fewer patient deaths prior to discharge," he said.
Dr. Saver suggests paring down the endovascular time targets of the guidelines. For example, door-to-puncture time goals should be reduced from 120 minutes to 90 minutes, picture-to-puncture times from 95 to 65 minutes, puncture to first-pass from 45 to 20 minutes, and puncture to revascularization from 90 to 40 minutes.
One way to cut down time is to begin treatment before the patient arrives at the hospital. Dr. Saver described a German study comparing outcomes of initiating lytic therapy in a mobile stroke unit (with a neurologist and a CT scanner on board the ambulance) to lytic therapy given when the patient reached the emergency department. The average time from alarm to treatment was twice as long for those given hospital lysis, compared with those treated by the mobile units (73 minutes vs. 38 minutes), although no differences were found in efficacy or safety outcomes. (Lancet Neurol. 2012;11:397-404).
"This is a remarkable acceleration of care," Dr. Saver said. By putting head-only CT scanners into ambulances, the German groups have the capability of performing not only noncontrast CT, but also CT angiography or perfusion CT on site. Dr. Saver’s team is also investigating whether other treatments given in the field, such as neuroprotective agents or antihypertensives, might be beneficial.
Other strategies to shave time include emergency medical services prenotification, having a stroke tool kit in place, and rapid triage and stroke team notification. He also recommends having a single-call activation system of the stroke team. TPA can be premixed and should be easily accessible and stored in the emergency department and radiology suite. At UCLA, a visual decision aid outlining the pros and cons of TPA allows families to make rapid informed consent.
Rapid treatment times also depend upon access to specialized stroke care centers. In 2010, 47% of the U.S. population, or 147 million Americans, lived in jurisdictions that routed stroke patients to the nearest hospital, not a primary stroke center (PSC). "But we have reached a tipping point now that more than half of the U.S. population resides in a stroke-center domain," Dr. Saver said. Since the early 2000s, there has been a shift from an acute ischemic stroke treatment model that relied primarily on transport of patients to PSCs or stroke-ready hospitals where they could receive TPA and other acute therapies safely and efficiently. Nowadays, favor is given to a two-tier system of spokes (PSCs) and hubs (comprehensive stroke centers that offer advanced treatments for complex patients, staffed by stroke specialists). More than ever, rapid identification and evaluation of stroke patients and effective differential diversion assessments are critical in reducing door-to-needle or door-to-recanalization times.
According to Dr. Saver, in 2005, only one-quarter of patients were being treated based on best practice standards of door-to-IV TPA of 60 minutes or less, and that level remained virtually unchanged through 2009. More recently, that number has begun to inch up. "Nationally, we are moving the curve, but the best centers are not going for 60 minutes door-to-needle, they are going for 30 minutes," he said, noting that nationally the fastest door-to-needle times in the United States are being reported by Washington University in St. Louis (39 minutes). The world’s record is 20 minutes in Helsinki.