This means a significant extension from the standard time-based protocol for acute stroke, which establishes the limiting threshold of the treatment to six hours after symptom onset.
At leading centers for stroke treatment, such as the Penn Stroke Center at the Hospital of the University of Pennsylvania, endovascular thrombectomy is performed up to 24 hours after stroke onset, if the imaging shows a possible therapeutic benefit.
Traditional time-based protocols establish a six-hour time window, after which it is assumed that the damage to the neural tissues due to the stroke could not be improved.
The results in both clinical trials suggest the important shift from a time-based stroke therapy approach to a tissue-based therapy approach, and the likely possibility to extend the opportunity time window threshold to 24 hours.
The results showcase very efficient improvement for thrombectomy patients, with 45% functional independence rate at 90 days compared to 17% in the standard medical treatment group.
The medical therapy consisted of thrombolytics 3 to 4.5 hours after stroke onset. Patients received CT perfusion or MRI with diffusion imaging.
The results show that in patients with large blood vessel strokes with favorable ischemic core to penumbra ratios, the endovascular therapy in addition to medical therapy at 6-16 hours after stroke onset resulted in improved neurological functional outcome.
The DEFUSE-3 clinical trial incorporated patients from 38 hospitals in the United States and data collected between May 2016 and May 2017.
The results revealed that 49% of the patients with thrombectomy achieved functional independence at 90 days, compared to 13% of patients who received only standard stroke unit care.
107 patients underwent mechanical thrombectomy plus standard medical therapy, 99 patients served as controls, with only medical therapy.
The DAWN clinical trial had incorporated 206 patients from 26 medical centres in U.S., Canada, Europe and Australia, between September 2014 and February 2017.
In the DAWN trial, were selected patients with a small eschemic core. a severe clinical deficit and an intracranial arterial occlusion within 6 to 24 hours after time they were last seen well.
Two recent clinical trials, DAWN and DEFUSE-3 studied the effect of extending the time window for endovascular clot retrieval (ECR).
CT angiogram and perfusion imaging are used to identify in the 6 to 24 hour time window the patients who most could benefit from intervention.
Recent advances in medical imaging and new clinical trials now allow to treat stroke in selected patients up to 24 hours after the onset of stroke symptoms.
New treatment approaches are targeted to 'freeze' the penumbra, while preventing the core to grow until complete canalization, as an adjunct therapy to mechanical thrombectomy. Special emphasis is placed on normobaric oxygen therapy, hypothermia and sensory stimulation.
However, most patients needed to have the angiogram started within 6 hours of symptom onset, a limited window of opportunity.
Controlled clinical trials performed during 2014-2015 showcased the efficiency of endovascular clot retrieval (ECR) which resulted in removal of large intracranial clots in 60% to 80% of patients, with functional independence at 90 days in about 50% of patients.
The downside of this treatment is that about 50% of the patients do not benefit from functional independence, because the core is already too large at the time of re-canalization.
Direct removal of the clot by mechanical thrombectomy significantly improves the outcome over IVT in up to 80% of ischemic stroke cases.
Patients with large proximal intracranial occlusion have about 70-80% risk of severe disability or death without re-canalization.
Intravenous thrombolysis has limited efficiency in patients with proximal intracranial occlusion, with re-canalization achieved in about 30% patients with proximal middle cerebral occlusion and only 10% in patients with terminal carotid artery occlusion.
Several re-perfusion strategies are targeted to rescue the penumbra.
Intravenous thrombolysis (IVT) can rescue the pernumbra if it is administrated within a time interval of up to 4.5 hours after the onset of the stroke. However, IVT provides only 30% re-canalization rate.
Without timely perfusion, the penumbra risks to become more and more reduced, while the infarcted core is enlarged. The increase of the ischemic core eventually leads to functional disability and even death.
Ischemic penumbra is a region of viable brain tissue at severe risk of infarction if re-perfusion is not achieved in time. These high risk areas add to the ischemic core, a region already infarcted.
Acute ischemic stroke usually occurs from the obstruction of an intracranial blood vessel resulting in the deficiency of nutrients in the area of the brain supplied by the blood vessel.
Brain functional disability as a result of ischemic stroke can be prevented by rescuing the ischemic penumbra, a severely non-perfused area around the infarcted tissue and highly at risk.
There is evidence that treatments could be effectively supplied beyond traditional time windows, whenever clinical neuroimaging detects the ischemic penumbra.
The identification of the 'ischemic penumbra' could lead to better, more informed decision-making, providing better outcome outside standard time windows.
Despite the physiological value of brain state evaluation using advanced CT and MR imaging techniques, they are often not used to select patients for intravenous or endovascular therapy, mainly because of limitations of time.
The determining factors of the decision about stroke treatment are the clinical aspects, the duration of time after stroke symptoms onset, and the presence of essentially negative findings on a non-contrast CT scan.
Any delay, starting with a lag in contacting the emergency medical system (EMS) eventually leads to a decrease in a patient's opportunity to receive time-sensitive advanced treatment.
Many people are not aware of the first signs and symptoms of a stroke, such as unilateral weakness and slurred speech and so don't seek immediate medical aid.
Rapid assessment and diagnosis are essential.
The first minutes and hours from the onset of stroke signs and symptoms are critical. They are tightly related to patient outcomes and could make the difference between mortality or neurological functional disability, and recovery, with long-term good quality of life.
This advanced imaging technique enables to assess large intracranial vessels, such as the internal carotid artery and middle cerebral artery trunk to detect occlusion.
After excluding hemorrhagic stroke based on NCCT results, CT angiography (CTA) can be performed in case of acute stroke in order to detect or determine the location of thrombus or occlusion.
Ischemic stroke accounts for 80% of all acute strokes, the remaining 20% are hemorrhagic strokes. However, ischemic strokes can be followed by hemorrhagic complications, leading to disability.
Ischemic stroke is the second most common cause of death worldwide, as well as the third highest cause of disability.
Non-contrast CT (NCCT) is the primary choice for initial evaluation of patients supposed to have undergone stroke.
This has been around for over a decade, nothing new. Learn the signs of a stroke and the hospital. You only have a small window of time for these therapy's to work.
I read this wrong at first...😂