Prompt Treatment Times Improve Endovascular Therapy Results for Stroke

For patients who receive endovascular treatment for stroke, longer times between initial computed tomographic (CT) imaging and groin puncture—so-called picture-to-puncture (P2P) times—are associated with poorer outcome. The findings, from a retrospective study, were published online February 7, 2013, ahead of print in Circulation.

Rishi Gupta, MD, of Emory University School of Medicine (Atlanta, GA), and colleagues reviewed outcomes of 193 patients who underwent endovascular treatment for anterior stroke at Grady Memorial Hospital (Atlanta, GA), a comprehensive stroke center, from November 2010 to July 2012.

Most patients (68%) were sent from referring centers because they had failed intravenous tPA within 4.5 hours of presentation or were not candidates for thrombolysis. The median transfer distance was 20 miles.

Transferred patients had longer median P2P times than those who presented directly to Grady Memorial, and they also were less likely to have a favorable Alberta Stroke Program Early CT Score (ASPECTS) prior to treatment. Subsequently, the prevalence of good clinical outcome, defined as modified Rankin Scale score of 0 to 2 at 90 days, was lower among transferred patients (table 1).

Table 1. Differences Between Transferred and Directly Admitted Patients

In a logistic regression model, longer P2P times predicted worse outcome (OR 0.994; 95% CI 0.990-0.999; P = 0.009), as did higher patient age (OR 0.972; 95% CI 0.947-0.998; P = 0.032) and NIHSS score (OR 0.88; 95% CI 0.82-0.95; P = 0.001). Successful reperfusion, on the other hand, was associated with better outcome (OR 3.68; 95% CI 0.42-9.53; P = 0.001).

The adjusted odds of good clinical outcome at 90 days decreased with longer treatment delays (table 2).

Table 2. Association Between P2P and Good Clinical Outcome at 90 Days

Among the many steps that contribute to P2P time, the decision-making time between initial CT and stroke center notification was responsible for 37% of the total. This process was longer when a neurologist was consulted for referral than when the emergency department physician directly called the center and when multimodal imaging was performed rather than noncontrast CT alone (P < 0.001 for both comparisons). Transfer time, meanwhile, added up to 47% of P2P time and correlated with distance but not transport method.

“Our current analysis points to a unique opportunity to improve efficiencies when transferring patients for endovascular reperfusion therapy,” Dr. Gupta and colleagues note. Possible strategies include setting minimum standards for transfer and sending patients directly to the CT scanner upon arrival at the referring hospital. CT images can then be uploaded to the stroke center for interpretation and records sent electronically, they suggest.

Starting the Conversation

In a telephone interview with TCTMD, Dr. Gupta said the level of awareness about treatment delays is still “in its infancy” for stroke. In fact, the term P2P was coined specifically for this paper to draw parallels with the effort to reduce door-to-balloon time (D2B) for STEMI patients. 

The hub-and-spoke model of STEMI networks can inform stroke care, he commented. “There’s no reason to reinvent the wheel. I think we can latch on to the same principles,” he said. “The only challenge that we have is that the CT scan is more difficult, because ECGs can be done in the field. We don’t have that capability.”

Dr. Gupta reported that researchers are initiating a voluntary registry “to address these questions and then start implementing certain changes to see if we can reduce national times.” Only recently did the Joint Commission begin accrediting stroke centers, he added. So far, there are 12 such hospitals, and the plan is to reach 200 nationwide.

Philip M. Meyers, MD, of Columbia University Medical Center (New York, NY), agreed that time “is clearly a piece of the puzzle, and anything you can do to make the triage of patients with stroke faster is important.”

However, he told TCTMD in a telephone interview that the situation is much simpler for STEMI. Not only do MI patients experience the symptom of pain, which is absent in stroke, but ECG provides an easy path to diagnosis.

“We don’t have that readily available test for stroke,” Dr. Meyers said. “I see a stroke patient, and I have no idea who’s going to get better and who’s not. That’s the big problem, it seems. When we have tried to study it, too many of the patients weren’t salvageable. And so we haven’t figured out who the trial population should be, and we don’t get good results. It really is turning out to be much more complicated than MI.”

The Specter of ISC 2013

Indeed, the International Stroke Conference (ISC), recently held in Honolulu, HI, was “a bad week,” Dr. Gupta related. Poor outcomes were seen for endovascular therapy patients in a number of trials including IMS III and SYNTHESIS Expanded.

But Dr. Gupta stressed that treatment delays could explain some of the poor results. A secondary analysis of IMS III, for example, showed trends toward better outcomes with faster treatment. “People have been fixated on other things, but time is probably the most important variable,” he said.

Newer trials including THERAPY, SWIFT PRIME, REVASCAT, and THRACE will provide a more contemporary look at endovascular therapy for stroke, Dr. Gupta said, adding, “It’s important that people don’t give up on it.”

Dr. Meyers described the results presented during ISC 2013 as “a major, major blow to endovascular stroke [treatment].” Time delay cannot entirely explain the poor showing, he said, pointing out that SYNTHESIS “got to people unbelievably quickly . . . and endovascular still didn’t work.”

Now, “we literally have to go back to the drawing board,” Dr. Meyers commented, advising that endovascular therapy should only be used “under research conditions” at the moment, in order to encourage better and faster trial enrollment.

“I agree; anything that shaves time off of the laborious process of getting a patient’s stroke evaluation completed is great. Now we just have to figure out what [the right treatment is],” he concluded.

Study Details

Mean age was 65.8 ± 14.5 years, and the median National Institutes of Health Stroke Scale (NIHSS) score was 19. There were no differences in age, past medical history, rates of IV tPA delivery, reperfusion success, or baseline NIHSS score at first hospital admission between the 2 groups.

 

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Source:
Sun C-H J, Nogueira RG, Blenn BA, et al. “Picture to puncture”: A novel time metric to enhance outcomes in patients transferred for endovascular reperfusion in acute ischemic stroke. Circulation. 2013;Epub ahead of print.

 

 

Related Stories:

• MR RESCUE: More Bad News for Endovascular Stroke Therapy
• SYNTHESIS Expanded: Endovascular Treatment No Better Than IV tPA for Acute Stroke
• IMS III: Endovascular Therapy Fails to Improve Stroke Recovery vs. t-PA Alone