Mr. Susman is a freelance medical writer based in Florida, USA. He travels worldwide to report from medical conferences, writing regularly for wire services, internet websites, and medical journals such as the Journal of the National Cancer Institute and AIDS.
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LOS ANGELES, California – The window of opportunity to aggressively reperfuse patients with strokes has been recommended in the new 2018 American Heart Association/American Stroke Association Guidelines for the Early Management of Patients with Acute Ischemic Stroke.
The recommendations mimic the protocol of the DEFUSE 3 study which showed remarkable recovery of stroke patients who missed the window of opportunity for treatment with tissue plasminogen activors (tPA) and were within 6 to 16 hours of the believed onset of symptoms.
In presenting the guidelines at the International Stroke Conference 2018, William Powers, MD, professor and chairman of neurology at the University of North Carolina, Chapel Hill, said the key recommendation for thrombectomy was:
“In selected patients with acute ischemic stroke within 6 to 16 hours of last known normal who have large vessel occlusion in the anterior circulation and meet other DAWN or DEFUSE-3 eligibility criteria, mechanical thrombectomy is recommended.”
The guidelines still suggest using tissue plasminogen activators (tPA) if the patient can be treated within 3 hours of the onset of stroke symptoms, but even in those cases of early response to stroke, the use of thrombectomy relies on meeting precise criteria.
“Patients should receive mechanical thrombectomy with a stent retriever if they meet all the following criteria:
1. A pre-stroke modified Rankin Score of 0-1.
2. Causative occlusion of the internal carotid artery or middle cerebral artery segment 1.
3. Age 18 or over.
4. National Institutes of Health Stroke Scale score of 6 or more.
5. Alberta Stroke Program Early CT Score (ASPECTS) of 6 or greater, and
6. Treatment can be initiated through a groin puncture within 6 hours of symptom onset.”
Dr. Powers said that the DAWN criteria that extends thrombectomy to as long as 24 hours after the last time the patient was seen well was also included in the new guidelines – albeit with a lower recommendation level. Whereas the DEFUSE-3 trial-based recommendations were assigned Level 1A evidence; the extension to 24 hours was given a Level IIa B-R recommendation.
That part of the guideline specifically stated:“In selected patients with acute ischemic stroke within 16-24 hours of last known normal who have large vessel occlusion in the anterior circulation and meet other DAWN eligibility criteria, mechanical thrombectomy is reasonable.”
The guideline writers also cautioned that before thrombectomy is attempted, proper imaging is required:
“In selected patients with acute ischemic stroke within 6-24 hours of last known normal who have a large vessel occlusion in the anterior circulation, obtaining CT perfusion, diffusion weighted MRI or MRI perfusion is recommended to aid in patients selection for mechanical thrombectomy, but only when imaging and other eligibility criteria from randomized control trials showing benefit are strictly applied.”
Stop unneeded tests
In the 60 pages of guidelines, Dr. Powers and colleagues generally left most treatment recommendations similar to the 2013 rendition. However, a major change was the recommendation to drop multiple tests that were routinely performed in stroke patients as part of secondary prevention.
“We took a very hard look at the cost benefit of doing diagnostic tests to decide what was the best treatment for patients to prevent them from having another stroke,” said Dr. Powers. “It is often assumed that just doing the tests is valuable in every patient and that is good medical practice. It turns out that is actually not good medical practice.”
He said these tests “are expensive; lead to studies that will provide no information that will provide no medical information about outcome and may actually lead to further tests and things that actually adversely affect patient outcome.
“We have made recommendations that diagnostic testing be individualized for each patient and restricted to answering those questions which will lead to a treatment change that will help the patients do better and not do them just because it is a checklist that is easy to do,” Powers said.
According to the new guidelines, evidence does not support routine use of these diagnostic tests in patients with acute ischemic stroke in attempts to assure this patient will not have a second stroke:
— Brain MRI (no benefit). This is a new recommendation.
— Intracranial CTA or MRA (no benefit). This is a new recommendation.
— Prolonged cardiac monitoring (clinical benefit is uncertain). This is a new recommendation.
— Echocardiography (no benefit). This is a new recommendation.
— Blood cholesterol if a patient is not on a statin (no benefit). This is a new recommendation.
— Obstructive sleep apnea (no benefit).This is a new recommendation.
— Hyperhomocysteinemia (no benefit). This recommendation is unchanged from the 2013 guidelines.
— Thrombophilic states (usefulness is unknown). This recommendation is unchanged from the 2013 guidelines.
— Antiphospholipid antibodies (no benefit). This recommendation is unchanged from the 2013 guidelines.
Another change in the guidelines applies to prevention of deep vein thrombosis in stroke patients who lie in bed for extended periods. Dr. Powers said the guideline writers determined that intermittent pressure applied to the legs is the best way to prevent clot formation in these patients.
“One of the feared complications of any hospitalized patient including those with stroke is that they lie in bed, they get blood clots in their legs. The blood clots can break off and go to their lungs and they can be fatal,” he said.
“For the purposes of their guidelines we very, very carefully evaluated the information as to what is the best way to prevent this and concluded that intermittent pneumatic compression – basically inflatable balloons that go on your calf and intermittently blow up and down to squeeze the blood out of the veins in your legs – are the most effective treatment for this,” he said. “We recommend that for all patients with stroke who are lying around in bed.”
The recommendation reads:
“In immobile stroke patients without contraindications, intermittent pneumatic compression in addition to routine care (aspirin and hydration) is recommended over routine care to reduce the risk of deep vein thrombosis.”
Dr. Powers noted that “previously blood thinners was advocated as the most effective way to do this. A very careful review of the available information indicates that this is a two-edged sword. It reduces the risk of blood clots in the legs traveling to the lungs but it also increases the risk of bleeding elsewhere in your body, and the overall benefit of this seem to be a wash, and their overall efficacy is really quite uncertain.”
The guideline relevant to this point reads:
“The benefit of prophylactic-dose subcutaneous heparin [unfractionated heparin or low molecular weight heparin] in immobile patients with acute ischemic stroke is not well established.”
While the guidelines represent a consensus they are not without friction. “The guideline changes were very controversial and stimulated a lot of unrest among the neurologists,” said James Grotta, MD, director of stroke research at the Clinical Institute for Research and Innovation at Hermann-Texas medical Center, Houston.
“In particular the removal of MRI, imaging of intracranial arteries, and cholesterol from routine evaluation of stroke patients is very controversial,” Dr. Gotta told Neurology Today. “Also, the strict requirement for advanced imaging before thrombectomy was debatable.”
He also was critical of the guidelines’ failure to mention other tools for treatment of stroke. “There are thing with some evidence behind them that were not included. In my own area, the use of Mobile Stroke Units, while still level 2 or 3 evidence, were not even mentioned, while other things with no greater evidence were included.” Dr. Grotta is director of the Mobile Stroke Unit Consortium.
April 2018 Health and Lifestyle