Outcomes of Endovascular Therapy for Acute Ischemic Stroke Getting Better Over Time
In recent years, use of endovascular therapy for acute ischemic stroke has increased modestly as patient outcomes have improved, according to a study published online February 13, 2015, ahead of print in Stroke. Better results have coincided with increased experience among clinicians and hospitals and with the use of new-generation thrombectomy devices.
Bijoy K. Menon, MD, of the University of Calgary (Calgary, Canada), and colleagues looked at data from the Get With The Guidelines-Stroke registry on 977,885 patients with acute ischemic stroke who were treated at 1,087 hospitals from April 2003 through June 2013.
Overall, 41.8% of hospitals provided endovascular therapy to at least 1 patient during the study period. The proportion increased from 12.9% in 2003 to 28.9% in 2012 (P < .0001) before dropping to 23.4% in 2013 after the results of 3 trials showing no benefit from endovascular therapy were released.
Endovascular therapy was used in only 1.6% of patients during the overall study period (1.1% alone and 0.5% with IV thrombolysis), although that figure grew from 0.7% in 2003 to 2.0% in 2012 (P < .001) before declining slightly to 1.9% in 2013. The type of endovascular therapy was not recorded in the registry. For comparison, 8.0% of patients received IV thrombolysis alone.
After multivariate adjustment, patient outcomes following endovascular therapy improved over time. The overall rate of symptomatic intracerebral hemorrhage was 9.7%, falling from 11.0% in 2010 to 5.0% in 2013 (P < .0001). In-hospital death occurred in 19.4% of patients overall, declining from 29.6% in 2004 to 16.2% in 2013 (P = .002).
In the most recent years, gains were made in the percentage of patients ambulating independently at discharge (24.5% in 2010 to 33.0% in 2013) and discharged directly home (17.7% in 2010 to 26.1% in 2013; P < .0001 for both).
The findings were similar in analyses accounting for baseline NIH Stroke Scale scores.
Rollercoaster Ride for Endovascular Therapy
Prior to February 2013, evidence supporting the use of endovascular therapy—intra-arterial thrombolysis, thrombectomy, angioplasty, or stenting—in acute ischemic stroke had been accumulating, the study authors say. But that month, the results of the IMS III, MR RESCUE, and SYNTHESIS Expansion trials, which failed to show a benefit from the addition of endovascular therapy to standard care, were reported, calling the usefulness of the approach into question.
“Advocates of endovascular therapy cited limitations of these trials, including low recanalization rates, prolonged time to endovascular intervention, broad imaging selection criteria, and lack of equipoise affecting patient enrollment as reasons why these trials failed to demonstrate any additional benefit in the endovascular arm,” Dr. Menon and colleagues note.
A shift in endovascular therapy’s fortune came in late 2014 with the release of results from the MR CLEAN trial, which showed that adding intra-arterial intervention with catheter-based thrombolysis, mechanical thrombectomy with newer stent retrievers, or both improved reperfusion and functional outcomes compared with usual care.
Then, in what was described as “a watershed moment in the field,” results from the ESCAPE, EXTEND-IA, and SWIFT PRIME trials—all of which demonstrated that adding mechanical thrombectomy to IV thrombolysis led to better reperfusion and functional outcomes—were presented earlier this month at the International Stroke Conference in Nashville, TN.
Better Devices Linked to Better Outcomes
The key to the better outcomes seen with endovascular therapy in recent years, the authors suggest, is the use of newer-generation devices.
“This time period coincides with increasing use of new mechanical devices like the Penumbra aspiration system ([FDA] cleared in 2008) and stentrievers ([FDA] cleared in
2012) for endovascular therapy,” they write. “These mechanical devices have higher recanalization rates than previous generation devices, achieve recanalization faster, and have lower complication rates.”
Additionally, they say that the Get With The Guidelines-Stroke registry results “raise the possibility that increasing use of newer mechanical devices has resulted in better clinical outcome, although other changes in practice, such as better patient selection, more technical expertise, better periprocedural care, and improved healthcare systems, may also explain some or all of the improvement in clinical outcomes in recent years.”
They conclude that “results of recent randomized trials of these new devices will… be critical in providing the evidence needed to justify reorganizing and further improving stroke systems of care.”
Menon BK, Saver JL, Goyal M, et al. Trends in endovascular therapy and clinical outcomes within the nationwide Get With The Guidelines-Stroke registry. Stroke. 2015;Epub ahead of print.
- The American Heart Association and the American Stroke Association provide funding for the Get With The Guidelines-Stroke registry. The program is also supported, in part, by unrestricted educational grants to the American Heart Association by Merck/Schering-Plough partnership and Pfizer.
- Dr. Menon reports no relevant conflicts of interest.