Mechanical clot removal can restore more function than drugs alone after severe stroke

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According to late-breaking preliminary research presented today at the American Stroke Association’s International Stroke Conference 2022, a premier global meeting for researchers and clinicians dedicated to the science of stroke and brain health, which was held in person in New Orleans and virtually, February 9-11, 2022.

In 2018, the American Heart Association stroke treatment guidelines were updated to recommend endovascular therapy (mechanical clot removal) for some stroke patients to improve the chances of functional recovery. Endovascular therapy involves threading a thin catheter through a vessel in the leg to mechanically remove a clot blocking a vessel in the brain.

A new study from Japan is the first randomized, controlled trial to demonstrate the effectiveness of endovascular therapy in patients with severe strokes involving clots in one or more large cerebral arteries, interrupting blood flow to a large part of the brain. The effectiveness of the approach had already been established for patients whose large vessel clots disrupted blood flow to fewer areas of the brain, however, clinical experience was mixed for patients with more severe strokes.

The infarct zone, or core zone, estimates the affected brain volume and describes the location of the blockage as seen on a brain scan. A lower number translates to a stroke affecting more central areas of the brain: 8-10 = small core, 6-7 = moderate core, and 0-5 = large core (larger and more severe strokes). Current US stroke guidelines recommend performing endovascular treatment for central areas 6-9. This study looked at blockages that affected the central areas of the brain more, specifically blockages rated 3 to 5. Strokes with blockages measuring 0 to 2 central areas are considered too severe and it is highly unlikely that the patient returns to ambulatory independence.

“I have often seen a dramatic improvement in a patient right after the mechanical clot removal procedure, even when the infarct area was large. Yet sometimes patients also experienced severe hemorrhagic transformation. [a life-threatening complication that occurs when blood from outside the brain crosses the blood-brain barrier and worsens stroke outcome] after the reopening of the artery. So in Japan, our stroke doctors are always cautious about endovascular therapy when the infarct area is large,” said Shinichi Yoshimura, MD, Ph.D., study lead author and professor of Medicine in the Department of Neurosurgery at Hyogo College. of medicine in Nishinomiya, Japan.

In this randomized study, 203 stroke patients (mean age 76 years; 44% female) were treated at 45 hospitals in Japan. Most (71%) were screened and had magnetic resonance imaging or CT scans of the brain within 6 hours of the onset of stroke symptoms, during which time patients are generally considered eligible for treatment endovascular. The remaining patients were seen between 6 and 24 hours after symptoms were detected, and additional imaging showed areas of the brain that could benefit from prompt treatment.

On imaging, all patients had clots blocking a major artery in the brain, either the internal carotid artery, the proximal middle cerebral artery, or both. The strokes were classified as severe (median of 22 on the National Institutes of Health (NIH) Stroke Scale, which assesses a patient’s ability to perform normal functions such as speaking and moving) and involved disruption of blood flow to large areas of the brain (about 7 out of 10 regions).

After imaging, patients were randomly selected to receive either standard medical care for stroke (administration of intravenous fluids, control of blood pressure and other risk factors, and administration of anti-clot medications for certain patients at low risk of bleeding) or standard medical care plus endovascular treatment performed within one hour of imaging to mechanically remove clots. Due to bleeding problems, intravenous anti-clot drugs were given sparingly to selected patients in a similar proportion in both treatment groups (27 of those who received endovascular therapy and 29 who received standard care ).

Comparing the 100 patients who received endovascular treatment with 102 on standard treatment alone, the analysis revealed:

  • Patients who received endovascular therapy were 2.43 times more likely (31% versus 13%) to be able to walk without assistance and to have residual disability rated as no to moderate 90 days later.
  • After 90 days, more patients (14% versus 6.9%) who received endovascular therapy were considered functionally independent, meaning they were either able to perform all of their pre-stroke activities, or that they had a slight disability that did not require daily care. assistance.
  • 48 hours after treatment, more patients (31% versus 8.8%) who received endovascular treatment showed major early neurological improvement (improved ability to speak and move limbs).

“Our results confirm that anyone who has had a stroke should be transferred to a medical facility capable of undergoing endovascular treatment as soon as possible. The benefit of endovascular treatment is not limited by the severity or region of a stroke. These patients may have the opportunity to more fully recover from a stroke and return to their previous life and activity levels,” said Takeshi Morimoto, MD, Ph.D., MPH, lead study author and Professor of Medicine in the Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan.

Several outcomes were compared to assess the safety of adding endovascular therapy to medical treatment, with the researchers reporting:

  • Within 48 hours, analyzes revealed that more patients who received endovascular therapy experienced bleeding in the brain (with or without symptoms), 58% versus 31%, respectively.
  • However, the number of patients who experienced other adverse effects was similar in the two treatment groups. Adverse events included bleeding in the brain within 48 hours that caused a worsening of neurological status (worsening of 4 or more points on the NIH Stroke Scale); the need for surgery to relieve pressure on the brain during the first week; death within 90 days; or recurrence of an ischemic stroke within 90 days.

“The finding of greater intracranial hemorrhage in patients who received endovascular therapy is very important. However, there were some hemorrhages with symptoms and others that caused no symptoms. detected on imaging performed for this study in the endovascular treatment group, not in the standard practice group.Symptomatic intracranial hemorrhage occurred even more frequently in patients in the endovascular group, however, there were no statistically significant difference from the standard care group,” Morimoto said.

The results of this study may not be generalizable to the United States or Western countries, as the study was conducted in Japan, where intravenous thrombolysis is used less than in the United States and other Western countries, and where more strokes are imaged with MRI than CT. (perhaps leading to different estimates of the number of brain regions affected by stroke). Due to these differences in treatment protocols, the results of this study may overestimate or underestimate the effectiveness of endovascular therapy.

The researchers are currently performing sub-analyses to help identify factors that might signal which patients are most likely to have better return to function after treatment. “In addition, rehabilitation tools, devices, or methods that could potentially improve the likelihood of similar patients recovering with less disability should be investigated,” Morimoto said.


Endovascular therapy studied for stroke due to basilar artery occlusion


Provided by the American Heart Association

Quote: Mechanical clot removal may restore more function than drugs alone after severe stroke (2022, February 9) Retrieved February 10, 2022 from https://medicalxpress.com/news/2022-02-mechanical-clot- function-medication-severe.html

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