Updated acute stroke guideline boosts thrombectomy

Pivotal new high-quality evidence from randomized clinical trials and other sources published since 2013 has prompted the American Heart Association and the American Stroke Association to update their joint clinical practice guideline on endovascular treatment of acute ischemic stroke.

The revisions were published online June 29 in Stroke.

Unchanged is the key recommendation that intravenous recombinant tissue-type plasminogen activator (r-tPA) remain the mainstay of initial therapy, even if endovascular treatment is being considered. But a new recommendation adds that a period of observation to assess patients’ clinical response to r-tPA before proceeding with endovascular therapy is not necessary and is not advisable, said Dr. William J. Powers, chair of the guideline writing committee and professor and chairman of the department of neurology, University of North Carolina, Durham, and his associates.

^{Courtesy American Heart Association}

Most of the updates pertain to the use of a stent retriever, which is now recommended for all patients with acute ischemic stroke who meet these seven criteria:

1. A prestroke modified Rankin scale (mRS) score of 0-1.

2. Receipt of r-tPA within 4.5 hours of symptom onset.

3. Causative occlusion of the internal carotid artery or proximal middle cerebral artery.

4. Age of 18 years or older.

5. A National Institutes of Health Stroke Scale (NIHSS) score of 6 or greater.

6. An Alberta Stroke Program Early CT Score (ASPECTS) of 6 or greater.

7. Initiation of the procedure within 6 hours of symptom onset.

Use of stent retrievers also is now considered “reasonable” in carefully selected patients with occlusion of the anterior circulation who have contraindications to r-tPA, such as current use of anticoagulants, prior stroke, serious head trauma, or hemorrhagic coagulopathy. It also may be reasonable in selected patients who have causative occlusion of the M2 or M3 portion of the middle cerebral arteries, anterior cerebral arteries, vertebral arteries, basilar artery, or posterior cerebral arteries, although the benefits are “uncertain” in this patient population.

Similarly, endovascular therapy using stent retrievers may be reasonable for some patients younger than age 18 who otherwise meet the seven criteria, even though the benefits of treatment haven’t been established in this age group. And it likewise may be reasonable in patients with prestroke mRS scores greater than 1, an ASPECTS of less than 6, or NIHSS scores of less than 6 if there is causative occlusion of the internal carotid artery or the proximal middle cerebral artery.

The updated guideline also says that stent retrievers are preferable to the Merci device, but that other mechanical thrombectomy devices may be reasonable to use in some circumstances. And adjunctive use of a proximal balloon guide catheter or a large-bore distal access catheter rather than a cervical guide catheter along with stent retrievers also may be beneficial.

In addition, “the technical goal of the thrombectomy procedure should be a TICI [Thrombolysis in Cerebral Infarction] 2b/3 angiographic result to maximize the probability of a good functional outcome. Use of salvage technical adjuncts including intra-arterial fibrinolysis may be reasonable to achieve these angiographic results, if completed within 6 hours of symptom onset,” the guideline states (Stroke 2015 June 29 [doi:10.1161/STR.0000000000000074]).

Also with regard to intra-arterial rather than intravenous fibrinolysis, stent retrievers are now preferable to intra-arterial fibrinolysis as first-line therapy.

The updated guideline also has added the recommendation that conscious sedation may be preferable to general anesthesia during endovascular therapy, depending on patient risk factors, tolerance of the procedure, and other clinical characteristics. It also revised recommendations addressing imaging studies and systems of stroke care.

Five prospective, randomized controlled trials have come out in the past few months, and triggered a revolution in acute stroke therapy. All five studies – MR CLEAN, ESCAPE, EXTENT IA, SWIFT PRIME, and REVASCAT – were halted early because of the significant advantage mechanical endovascular therapy with stents or thrombus retrieval devices demonstrated over standard therapy featuring clot thrombolysis with r-tPA.

Collectively, the five trials showed a 60% greater chance for good functional recovery from stroke with endovascular interventions. The rate of a favorable neurologic outcome as reflected in a modified Rankin score of 0-2 was 48% with the use of stent/retriever devices, compared with 30% with thrombolysis alone, said Dr. Petr Widimsky, professor and chair of the cardiology department at Charles University in Prague, at the annual congress of the European Association of Percutaneous Cardiovascular Interventions (EuroPCR) held in Paris in May.

The American Academy of Neurology “affirms the value of this guideline as an educational tool for neurologists.” The revised guideline is endorsed by the American Association of Neurological Surgeons, the Congress of Neurological Surgeons, the American Society of Neuroradiology, and the Society of Vascular and Interventional Neurology. A copy of the document is available at http://myamericanheart.org/statements.