Study: Adding tPA to Thrombectomy Does Not Enhance Outcomes
New research found that using intravenous thrombolysis (IVT) with tissue plasminogen activator (tPA) did not improve outcomes among stroke patients undergoing mechanical thrombectomy (MT).
Noting that it is not known whether IVT is of additional benefit in patients undergoing MT, investigators sought to examine whether treatment with IVT before MT with a stent retriever is beneficial to patients undergoing MT. Their post hoc analysis used data from 291 patients treated with MT who were included in 2 large, multicenter, prospective clinical trials that evaluated MT for acute ischemic stroke (Solitaire With the Intention for Thrombectomy [SWIFT], performed from January 1, 2010, through December 31, 2011, and Solitaire Flow Restoration Thrombectomy for Acute Revascularization [STAR] from January 1, 2010, through December 31, 2012).
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An independent core laboratory scored the radiologic outcomes in each trial, and patients were treated with IVT with tPA followed by MT (IVT and MT group) with the use of a stent retriever or MT with a stent retriever alone (MT group). Among the 291 patients included in the analysis, 160 underwent IVT and MT, while 131 underwent only MT.
While observing that the use of IVT with tPA had no disadvantages, the authors found that at 90 days after stent retriever therapy with the Solitaire device for acute ischemic stroke, functional independence was equally likely between those who received additional tPA infusion and those who did not. Likewise, mortality rates were similar at 90 days for the tPA group (8.1%) and the group that underwent MT alone (12.2%).
"Although these results are very interesting, our study is not the final word," said Vitor Mendes Pereira, MD, MSc, associate professor of radiology and surgery at the University of Toronto, and a coauthor of the study, noting that a randomized controlled trial is warranted.
"Many new questions have been raised, now that we demonstrated the benefit of MT. The role of tPA for patients with large vessel occlusion is the next big question," Dr Pereira said. "The answer may have a safety and cost effectiveness impact on direct patient care and on stroke systems on regional and national levels worldwide."
Patients with National Institutes of Health Stroke Scales (NIHSS) scores of 4 or more who present within 3 hours of stroke should still be considered for intravenous tPA if other inclusion/exclusion criteria are met, added study coauthor Wayne Clark, MD, director of the Oregon Stroke Center at Oregon Health & Science University.
"This is true even for large strokes that are going for thrombectomy," Dr Clark said. "Even for these larger strokes, there is a 10% chance the tPA alone may open the vessel. However, patients with NIHSS greater than or equal to 8 with cortical signs should be referred or transferred for potential thrombectomy immediately. Don’t wait for the tPA to finish."
—Mark McGraw
Reference:
Coutinho JM, Liebeskind DS, Slater L-A, et al. Combined intravenous thrombolysis and thrombectomy vs thrombectomy alone for acute ischemic stroke: a pooled analysis of the SWIFT and STAR studies [published online January 9, 2017]. JAMA. doi:10.1001/jamaneurol.2016.5374.