Resetting the Clock: Stent Retrievers & the Race to Stop Stroke

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“Time is brain,” physicians say. As they ponder new data on acute stroke intervention with stent retrievers, many are advocating for new systems and a team-based approach modeled after the successful door-to-balloon time protocols that have vastly improved heart attack outcomes. Others note the healthcare dollar is stretched thin and wonder if the formidable costs of endovascular stroke intervention will prohibit nationwide implementation. 

In addition to the personal toll on patients and families, stroke has had a similarly crippling effect on the U.S. healthcare system. According to the Centers for Disease Control and Prevention, stroke costs the United States $34 billion annually in healthcare services, medications and lost productivity. It is the leading cause of serious long-term disability and is responsible for 1 in 20 deaths, or 130,000 deaths per year.

With such harrowing statistics, the results of five trials published in 2015 in The New England Journal of Medicine (NEJM)—MR CLEAN, EXTEND-IA, ESCAPE, REVASCAT and SWIFT PRIME—become all the more remarkable. In the studies, stent retrievers—a catheter-based approach for mechanical thrombectomy—plus intravenous tissue-type plasminogen activator (IV tPA) improved outcomes compared with standard of care IV tPA in patients with acute ischemic stroke.

“Up until these recent five trials, data were really not conclusive that stroke reperfusion, other than tPA … was beneficial,” says Christopher J. White, MD, chair of medicine at Ochsner Clinical School of Medicine, University of Queensland, New Orleans. “We knew from the beginning that opening occluded arteries would benefit patients. We just had a heck of a time proving it.”

White says that the major struggle came because the preceding trials did not select the right patients. “Part of [the issue] was understanding how to bring this therapy to the right patient,” he says. “We say, ‘the right patient, the right device at the right time.’ And now it’s the perfect storm. Five trials all of a sudden say open arteries are better than closed arteries.”

Early endovascular treatment stressed

Shortly after the publication of these data, the American Heart Association (AHA) and the American Stroke Association (ASA) released the “2015 AHA/ASA Focused Update of the 2013 Guidelines for the Early Management of Patients With Acute Ischemic Stroke Regarding Endovascular Treatment.”

Authored by AHA Stroke Council members, the new document emphasizes the endovascular approach among patients similar to those examined in the five clinical trials, stating that patients should receive endovascular therapy with a stent retriever if they meet all of seven criteria (see sidebar at right).

Yet, according to William J. Powers, MD, chair of the guidelines and H. Houston Merritt Distinguished Professor and chair of the Department of Neurology at the University of North Carolina at Chapel Hill, what has been even more telling than the speed at which the revisions were made is the change to his daily practice.

“Recently, during a one-week period, we evaluated five people for this treatment … and treated three, which were as many [intra-arterial interventions] as we used to do in a year,” Powers says. “And of the three, one of the patients got dramatically better. This patient was completely paralyzed on one side and semi-comatose when he went to treatment. He walked home two days later.”

The catch: Timeliness is money

Although the data and early reports of patient experience have been encouraging, not many regions in the United States are currently set up to handle this time-sensitive procedure.

According to the AHA, although all 90 comprehensive stroke centers certified by the association and the Joint Commission perform mechanical thrombectomy, many states in the Midwest don’t have a single accredited comprehensive stroke facility (see “Stents for Strokes” map). The AHA added that the procedure is offered at some of the more than 1,000 AHA/Joint Commission certified primary stroke centers.

David J. Cohen, MD, MSc, director of cardiovascular research at St. Luke’s Mid America Heart Institute in Kansas City, Mo., and investigator in the SWIFT PRIME trial, speculates that the biggest challenge to providing this therapy is transporting patients to stroke centers and delivering these therapies in a timely fashion.

“These therapies only work within the first few hours of a stroke, and we continue to have challenges in recognizing the symptoms in these patients and getting them to a stroke center quickly enough,” Cohen says. “So we need to make a concerted effort as a country and healthcare system to make sure these therapies are widely available in places where patients have stroke.”

White adds that delivering timely care requires a network of referrals and a costly, complex system of transportation that is not really in place today. “There are lots of patients who are having strokes in locations where there is no one to provide this care,” he says.

Powers believes that not every hospital could or should have the technical expertise on site necessary to handle these patients. “The volume in any small hospital is never going to be enough to support [these physicians],” he says. “They need to have a day job. These [patients] come in once in a while, and how can you justify paying someone’s salary to do two or three cases a week? What it is going to boil down to is the bigger the healthcare system, the more they can handle it.”

For these larger hospital systems, the disposable costs associated with stent retrievers shouldn’t be a barrier to usage, according to White. “This is not an incremental increase given what we used to use as standard technology, ... not to mention other catheters, stents and balloons,” he says. “Secondly, there isn’t additional training required to use this device. Anyone who is competent to perform intracranial interventions with the conventional devices and stents easily uses the stent retriever. It’s very easy to learn and simpler compared with what we used to use.”

Cost vs. benefit

As healthcare systems continue to weigh the cost and benefits of stent retrievers for acute ischemic stroke, early data suggest that the procedure may be cost effective.

A pooled analysis of the five NEJM trials concluded that although the upfront costs of thrombectomy were high, the potential quality-adjusted life year (QALY) gains resulted in the intervention being cost effective. Specifically, the incremental cost per QALY gained during a 20-year period was $11,651 (Stroke 2015;46:2591-2598).

“This along with another analysis I’ve read [Stroke 2015; doi:10.1161/strokeaha.115.009779] would suggest that the clinical gain is well worth the additional cost,” Cohen says. “Although I’m not sure whether [stent retrievers] will ever save the healthcare system money, we should not think of that as the goal. Our goal is to improve the lives

of our patients. And I think it can do that at a very reasonable price, even now.”

Cohen adds that he and fellow SWIFT PRIME trial investigators are working on a cost-effectiveness analysis that is planned for presentation in early 2016.

New paradigm?

In recent years, the heart team, an interdisciplinary approach involving interventional cardiologists and cardiac surgeons, has transformed the way patients with structural heart disease receive care. Now, some are asking if a “brain team” consisting of cardiologists and neurologists should be established for acute stroke care

“I think it’s the only way for the procedure to be done,” White says. “Anyone who has the skills to do carotid stenting [like cardiologists, vascular surgeons and neurosurgeons] should be able to do acute stroke care—but there needs to be a neurologist who is the captain of the team.”

Another paradigm within cardiology that could teach valuable lessons to acute stroke care practitioners is the STEMI door-to-balloon model.

Although there are different sets of challenges for acute stroke vs. STEMI care, Powers says, “The treatment for STEMI patients is to get them someplace where someone can do the acute angioplasty and stent. [Acute stroke care] is very much like that. We have used some of the lessons from STEMI … to streamline our treatment.”

Going forward, White believes measurements for door-to-balloon time will become as much the national standard for stroke management as it has for STEMI.

“Neurology and neurosurgery have typically not been held to the door-to-balloon or door-to-device time for stroke, because we haven’t had evidence to support that. Now we do,” he says. “So there is really no excuse not to be quick to reperfusion and to expedite the care for these patients.”