Endovascular (intraarterial) treatment of acute ischemic stroke: efficacy not supported by clinical trials.

Intravenous tissue plasminogen activator (IV tPA, alteplase) provides a statistically and clinically significant improvement in clinical outcome for carefully selected patients with acute ischemic stroke when administered within 4.5 hours of onset; however, even within the 4.5-hour window, outcome is poor for some eligible patients, including those with occlusions of large arteries (internal carotid, middle cerebral, and basilar) and many patients do not meet the stringent eligibility criteria, especially the time requirement. Intraarterial (also known as endovascular or neurointerventional) therapies have been developed to address these needs. This review summarizes the current evidence for the efficacy of endovascular treatments in acute ischemic stroke. Randomized controlled clinical trials of acute ischemic stroke do not show any added clinical benefit of endovascular treatment over IV tPA alone in IV tPA-eligible patients, even in patients with persistent large-artery occlusion, nor have these trials provided evidence of clinical benefit in patients ineligible for IV tPA because they are >4.5 hours from onset, even if selected by sophisticated neuroimaging. The new stent retrievers, however, were rarely used in these trials. It remains to be determined from trials with direct head-to-head comparisons whether these new devices are superior to standard nonendovascular therapy. If there is a role for endovascular treatment of acute ischemic stroke, it is for patients who can be treated under 4.5 hours but who are ineligible for IV tPA because of increased hemorrhage risk from systemic thrombolytic drug effects, although this remains unproven.