New Generations of Devices Improving Treatment Outcomes for Stroke

July 27, 2015—The Society of NeuroInterventional Surgery (SNIS) announced that two new studies released at the SNIS 12th annual meeting in San Francisco, California, reinforce the value and progress of intra-arterial treatment for stroke. The investigators concluded that the innovative new devices that facilitate this approach are reducing treatment times, improving outcomes, and decreasing mortality rates.

With stent retrievers, which became available in 2012, there has been no comparative analysis with preretriever devices to determine differences in utilization or clinical outcomes. The first of the two studies at SNIS, “Trends and Outcomes of Mechanical Thrombectomy in Patients With Acute Ischemic Stroke: a Review of National In-Patient Database,” was conducted by Srikanth Boddu, MD, and Ning Lin, MD, at New York Presbyterian Hospital and Weill Cornell Medical Center in New York, New York.

The investigators used the Nationwide Inpatient Sample database provided by the Agency for Healthcare Research and Quality to analyze outcomes across three generations of devices: 2006–2007 “Post-Merci” (Merci retrieval system, Stryker Neurovascular); 2008–2011 “Post-Penumbra” (Penumbra aspiration system, Penumbra, Inc.); and 2012 “Stent Retriever” era.

According to SNIS, the results showed that as the number of stroke cases climbed across these three time periods, from 723,327 to 738,490, the rate of deaths decreased with newer devices. In 2012, stent retrievers were associated with a mortality rate of 17.1% versus preretriever devices in both 2008–2011 (19.3%) and 2006–2007 (25%). Additionally, the age-specific mortality rate after stroke intervention decreased with newer devices for patients aged 80 years or older and aged 65 to 79 years: 2012 (20% and 14.9%, respectively) compared to 2008–2011 (25.8% and 20.5%, respectively) and 2006–2007 (26.3% and 30.2%, respectively). 

SNIS advised that these findings are significant because they demonstrate that older patients can benefit from intra-arterial therapy and that age alone is not an exclusion criterion for interventional treatment. 

In the SNIS press release, Dr. Boddu commented, “It is clear that the introduction of stent retrievers for stroke treatment has been a significant game changer. Not only have these tools provided practitioners with new approaches to treatment, but we have also proven that innovation is worth the investment. With treatment advances, we are seeing increasing numbers of patients survive stroke.” Dr. Boddu is an interventional neuroradiologist at the Weill Cornell Brain and Spine Center.

The second study, “Implementation of New Technological Advances of Endovascular Treatment in Acute Ischemic Stroke Provides Overall Improvement in Procedural Times,” was conducted at the Swedish Medical Center in Englewood, Colorado. SNIS President Donald Frei, MD, served as Lead Investigator of the study. Dr. Frei is a neurointerventionist at Swedish Medical Center.

In this study, the investigators sought to understand if the new devices were associated with better outcomes and shorter procedural times. They conducted a data analysis across six prospective and retrospective endovascular treatment trials, in which various evolutions of the Penumbra aspiration system were used as the primary therapy. 

The study of 932 patients showed that the newer and larger Penumbra catheters provided a faster and more efficient method for treating acute ischemic stroke.

When considering the variables of age, baseline National Institutes of Health Stroke Scale score, and posttreatment status of restoration of blood flow, the investigators reported that shorter procedural times were a significant predictor of better clinical outcomes at 90 days, as measured by the modified Rankin scale.

In the SNIS press release, Dr. Frei commented, “As each new generation of devices provides improved tools for our treatment arsenal, we are able to adjust our approach to maximize efficiencies and results for our patients. Time is the most important factor when treating a stroke, so it is incumbent upon all of us to use every tool at our disposal to achieve fast and effective treatment. Thankfully, each generation of new devices has proven to reduce procedure time, which raises the chance of a successful operation.”