Written by Karygiannis Michail MD, Interventional Radiologist - Neuroradiologist, Director of Interventional Neuroradiology Department, Athens Medical Center, Athens Medical Group
Worldwide, over the last 5 years, special centers and medical units for the treatment of patients with acute ischemic stroke have been organized. This is because the contribution of intra-arterial interventions to address those with acute ischemic strokes is continuously enhanced and developed. The Interventional Neuroradiology department of the Athens Medical Center has performed the largest number of surgeries in Greece, with results corresponding to those of major European centers.
Strokes are the most important cause of disability in adults and one of the leading causes of death worldwide. In our country it is estimated that each year there are 30 to35 thousand new strokes, while total hospital admissions due to strokes exceeds 40 thousand annually. Strokes, beyond the urgency of the situation that must be handled, have serious physical, mental, social and economic consequences not only for patients but also their families.
Strokes are distinguished in ischemic strokes, which are more frequent and are 85% of total strokes, and hemorrhagic strokes (15%).
Ischemic strokes (IAEE) occurs when the arterial blood supply is interrupted in a portion of the brain. This is due to obstruction of large arteries in the brain or of small arteries within the brain. The obstruction is caused by either creation of a clot in an artery stenosis (thrombosis), or a clot formed normally in the heart that moved in the brain arteries by blood flow (embolism).
However, the functioning of brain cells requires a continuous supply of oxygen and glucose in the bloodstream. When the blood supply to part of the brain is interrupted by a stroke, a disturbance in the functioning of brain cells is caused and then these cells die.
In acute ischemic stroke, immediate treatment is necessary to prevent the spread of damage to a larger area of the brain, where the blood supply is reduced but has not stopped.
Symptoms of ischemic stroke
When brain cells do not have sufficient oxygen, they cease to perform their usual “duties”, in other words their functions. Symptoms following a stroke depend on the area of the brain that is affected and the extent of the damage. When any of the following stroke symptoms appear suddenly, medical assistance should be immediately requested.
- Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
- Sudden confusion or difficulty in speaking or understanding
- Sudden difficulty in sight of one or both eyes
- Sudden dizziness, loss of balance or coordination of movements
It is important that if any of these symptoms of stroke occur, to visit a doctor as soon as possible. This is because the possibility of therapeutic intervention in patients with acute ischemic stroke is directly dependent on the time between the onset of symptoms and the start of treatment.
The restoration of blood flow in the occluded cerebral artery, especially within the first 6 hours, results in an increase (4-5 times) of functional recovery and a reduction of the risk of death (up to 5 times).
Patients who manage to go to an organized stroke center that and are subjected to the necessary laboratory and imaging tests for up to 4,5 hours after the onset of symptoms, are able to receive intravenous thrombolytic therapy (administration of a substance that dissolves the clot).
The time window of 4,5 hours is very limited and most times patients with stroke do not arrive at the hospital in time or have contraindications for the use of this medicine.
40% of ischemic strokes involve a large degree of occlusion of the cerebral vessel (such as the internal carotid artery, the main artery, the middle cerebral artery) with mortality rates between 30% and 90%. In these patients the response to intravenous administration of thrombolytics is unfortunately very small.
The need to extend the therapeutic time window from the onset of stroke and the treatment of patients with occlusion of the large blood vessels, led to the development of intra-arterial therapy, which includes intra-arterial thrombolysis and intra-arterial thrombectomy or mechanical thrombolysis.
Intra-arterial thrombolysis (effusion of thrombolytic substance directly into an occluded artery) can be applied for up to 6 hours after the onset of the symptoms of stroke, providing a 60% chance of opening of the occluded artery.
Intra-arterial thrombectomy or mechanical thrombolysis (clot removal) can be applied for up to eight hours (up to 12 hours in the posterior circulation) after the onset of stroke symptoms, offering a 80% probability of opening of the occluded artery.
- Patients who completed their laboratory examinations (neurologic assessment, blood tests and imaging) after 4,5 hours and before 8 hours from the onset of stroke symptoms
- Patients administered intravenous thrombolytic substance within 4,5 hours and showed no improvement
- Patients with a contraindication to administration of thrombolytic substance
- Patients with occlusion of a large artery and imaging indicating enhancement of a region of the brain with no necrosis, but at risk
Intra-arterial thrombolysis is performed under fluoroscopic monitoring (Digital Angiography) after puncture of the femoral artery, as is diagnostic digital angiography. Then, a guiding catheter (thin tube with a diameter of 2 mm) is advance to the carotid artery or vertebral artery (central arteries of the brain located in the neck) that supply the occluded cerebral artery. Through the guiding catheter, a microcatheter is advanced up the artery with the clot and the thrombolytic substance (r-tPA) is thereby effused directly to the thrombus.
In intra-arterial thrombectomy, the procedure followed for placement of the guiding catheter is the same as that of intra-arterial thrombolysis described above, but, with the guiding catheter an apparatus is advanced, which captures the thrombus, and then device and thrombus are removed from the artery.
The intra-arterial therapy surgery is usually performed under general anesthesia. Many times a combination of intra-arterial thrombolysis and thrombectomy is performed. Thus, depending on the artery blocked, thrombectomy is done when thrombolysis is not efficient or thrombolysis is done after thrombectomy so as to dissolve small clots in thin peripheral arterial branches.
The department of Interventional Neuroradiology at the Athens Medical Center has been in operation since 2001, having performed more than 1.500 surgeries. It has a digital angiogram of modern technology, is staffed by specialized and experienced personnel (doctors, radiology technologists, nurses) and covers emergencies 24 hours a day.
Michael Karygiannis, Interventional Radiologist - Neuroradiologist Sci. Head of Interventional Neuroradiology Athens Medical Center.