Endovascular Therapy May Result In Significantly Better Outcomes Than Current Standard Treatment For Deadliest Strokes

Results Announced at Society of NeuroInterventional Surgery (SNIS) 9th Annual Meeting

SAN DIEGO, July 27, 2012 /PRNewswire-USNewswire/ -- Endovascular therapy (EVT) is associated with significantly better treatment outcomes over traditional intravenous tPA (IVT) for patients suffering acute ischemic stroke resulting from blockages in the large vessels, or major "highways" of the brain, according to a study presented at the SNIS 9th Annual Meeting in San Diego.  Statistics from the American Stroke Association indicate that 87% of stroke cases in the U.S. each year (estimated at 795,000) are ischemic strokes, and of this total, approximately 50% are large vessel occlusions (LVO), blockages associated with significant morbidity and mortality.  

According to Ansaar Rai, M.D., Associate Professor, West Virginia University Medical Center and study author, "For a disease as devastating as stroke, it is imperative that the medical community focuses collective attention on producing comparative data to determine which treatments offer the best outcomes and benefits to our patients."  The first-time single center retrospective study assessed outcomes from 223 patients over an eight-year period from 2003 to 2012 who suffered LVO strokes and were treated by either EVT, a technique that uses devices or drugs directly at the problem site to dispel clots and restore blood flow, or IVT, an intravenous delivery of drugs still considered the standard treatment for stroke.  For purposes of this study, a large vessel refers to either the internal carotid artery terminus (ICA-T), or the middle cerebral artery (M1 or M2).

Across 123 patients who received EVT and 100 patients who received IVT, baseline results showed that 81 subjects (36.3%) met the primary endpoint as defined by a 90-day modified Rankin Score* (mRS) < or = 2 (favorable outcome). The overall mortality rate was 36.3%.  

Comparison data showed that, overall, EVT resulted in more favorable outcomes than IVT, 44.7% to 26% respectively (p=0.003, OR 2.3, 95%CI 1.3-4.1).  The mortality rate was 31.7% for EVT and 42% for IVT.  When incorporating occlusion sites into comparison data, EVT also showed notably better outcomes than IVT:

Occlusion Types

Favorable Outcomes

P

OR (95%CI)

EVT

IVT

ICA-T

27.6%

0%

p=0.004

M1

40%

10.5%

p=0.0007

OR 5.7, 95%CI 1.8-17.7

M2

76%

47.8%

p=0.02

OR 3.4, 95%CI 1.2-10.2

Additional findings showed that age, occlusion site and treatment type were the best predictors of favorable treatment outcomes, with EVT producing superior results over IVT:

  • For strokes in the ICA-T site in patients under 80 years of age, a favorable outcome was seen in 36.8% of EVT patients as compared with 0% of IVT patients (p=.01)
  • For strokes in the M1 site in patients under 80 years of age, a favorable outcome was seen in 47.9% of EVT patients as compared with 15% of IVT patients (p=0.007, OR 5.2, 95%CI 1.3-20)
  • For strokes in the M2 site in patients under 80 years of age, a favorable outcome was seen in 88.2% of EVT patients as compared with 60% of IVT patients (p=.03, OR 5, 95%CI .9-27

EVT was found to be an independent predictor of favorable outcomes despite some differences in baseline characteristics between the two groups. EVT patients were younger than IVT patients, with a mean age of 68 to 76 respectively.  For M1 occlusions, significantly more patients underwent EVT over IVT (56.1% to 38% respectively), and for M2 occlusions, more patients underwent IVT as compared with EVT (46% to 20.3% respectively). For ICA-T occlusions, treatment rates were similar, 23.6% for EVT patients as compared to 16% of IVT patients.  There was no statistical difference in other variables, including number of female patients, mean NIH Stroke Scale score (a standardized measure used to clinically evaluate the degree of impairment of a stroke), and rate of diabetes, hyperlipidemia, hypertension and atrial fibrillation. 

As comparison data reveals a significant high failure rate for IVT across all occlusion sites (100% for ICA-T, 90% for M1 and 52% for M2), contrasted with favorable outcomes for EVT, particularly in younger patients with ICA and M1 occlusions (36.8% and 47.9% respectively), Rai says this study strongly suggests the need for a randomized trial including head-to-head comparisons of EVT versus IVT.  "Such an initiative on the part of the neuroscience community could definitively transform our treatment approach to this disease by advancing the science that will make it possible to improve outcomes for the benefit of thousands of patients and their families."

About SNIS
Founded in 1992, the Society of NeuroInterventional Surgery (SNIS) is represented by physicians who specialize in minimally invasive techniques to treat neurovascular conditions, including stroke, aneurysms, carotid stenosis and spinal abnormalities.  Drawing on diverse backgrounds and expertise including interventional neuroradiology, neurosurgery and neurology, these physicians are continuing to forge new pathways in the development of the distinct specialty of neurointervention.  Over the past two decades, practitioners of this field have paved the way for the scientific research and study that has resulted in new technology and revolutionary treatment approaches that have transformed the neurosciences.  In keeping with the mission of SNIS, the society remains committed to working in partnership to advance the science and medical environment that will result in enhanced quality of care for patients across the globe.  www.snisonline.org.  Follow us on Twitter @SNISinfo.

* The Rankin score is a measure of the degree of disability in people who have suffered a stroke.

SOURCE Society of NeuroInterventional Surgery

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