Cerebro refers to the large part of the brain and the root vascular refers to veins and arteries. Cerebrovascular is referring to blood flow in the brain. Cerebrovascular disease is made up of disorders that affect the brain by bleeding. This can include strokes, carotid stenosis, vertebral stenosis and intracranial stenosis, aneurysms, and vascular malformations
Stenosis can happen because of a blocked blood flow and well as clot formations, embolisms, and hemorrhages. Ischemia is the lack of blood flow to the brain. Ischemia can lead to strokes.
BLOOD FLOW TO THE BRAIN
Two sets of arteries are used to pump blood to the brain. These two arteries are called the carotid arteries and the vertebral arteries. The carotid arteries branch off near the top of the neck into external and internal arteries. The external arteries supply blood to the face while the internal arteries supply blood to the skull. The internal arteries in the skull branch into the anterior cerebral and middle cerebral arteries as well as smaller arteries including the ophthalmic, posterior communicating and anterior choroidal arteries. These arteries are responsible for ⅔ of the blood flow to the brain.
The vertebral arteries go along the spine. They come together to make a basilar artery near the brainstem. The vertebrobasilar system will send small branches into the brain stem which further branch off to make the posterior cerebellar and meningeal arteries. These arteries supply the part third of the brain. Jugular veins carry blood outside of the brain.
The brain is dependent on two sets of major arteries to receive blood. When a carotid artery is blocked due to a fatty plaque, this can cause an ischemic stroke. A hemorrhagic stroke happens when an artery of the brain leaks or bursts leading to brain bleed.
Proper blood flow in the brain needs to be restored as quickly as possible. The brain cells can quickly be damaged and die within minutes of blood flow without oxygen or nutrients. If a brain cell dies, it can not be repaired so disabilities may arise.
CEREBROVASCULAR STATISTICS
- Around 157,803 deaths were related to cerebrovascular disease in 2003. 138,397 of the deaths were people over the age of 65
- This disease is responsible for around 40,000 attacks each year and is 10% of all ischemic strokes. Strokes are the third main causes of death each year in the US. Of 700,000 affected people every year, 500,000 are first attacks and 200,000 are recurring attacks. Around ¼ of people who recover from a stroke will have another stroke within 5 years.
- Stroke is the main cause of a severe disability. There are around 5.4 million stroke survivors alive today. In 2003, The American Heart Association estimated around 5,400,000 people have had strokes.
- Every year, 30,000 people in the US have had a ruptured cerebral aneurysm. 6% of people may have a ruptured aneurysm
- AVMs are present in around 1% of the population. There is around a 4% chance of hemorrhage risk per year and 15% chance of stroke or death with every hemorrhage.
CEREBROVASCULAR DIAGNOSTIC TESTS
Diagnostic testing can help to identify cerebrovascular problems.
- Cerebral angiography: A patient is given a local anesthetic and the artery usually in the leg is punctured and a needle is inserted into the artery. A catheter is inserted through the needle and is threaded through the main vessels of the chest and abdomen until it is in the neck. A contrast dye is injected to the neck area and X-rays are taken
- Carotid Duplex: the ultrasound is used to help detect plaque, blood clots, and blood flow issues. A water - soluble gel is placed on the skin and an ultrasound is taken of the carotid arteries.
- CT or CAT scan: To look at bone, blood, and brain tissues.
- Doppler ultrasound: water-soluble gel is put on a transducer and skin and the machine will make a swishing sound if normal.
- EEG: Small electrodes are placed on the scalp to test electrical impulses
- Lumbar Puncture: Invasive test that removes CSF from the spinal cord to help detect bleeding
- MRI: 3D images of the body will be taken
- MRA: noninvasive study to see the blood vessels in the brain and neck areas.
STROKE
A stroke arises when there is a blockage of blood flow to the brain that leads to neurological dysfunction. An ischemic stroke is caused by a blockage of blood flow, or an interruption can be caused by brain bleeding which causes hemorrhagic strokes. 80% of strokes are ischemic strokes.
Stroke Symptoms
- Dizziness, nausea, vomiting
- Headaches
- confusion or memory loss
- Numbness or weakness in arms, leg, face
- Speech issues
- Vision issues
- Balance issues
Stroke Treatments
Ischemic Stroke
This is the most typical stroke. An ischemic stroke can be thrombotic or embolic. A thrombotic stroke happens when a blood clot called a thrombus blocks an artery to the brain and blocks the blood flow. An embolic stroke happens when plaque or thrombus blocks an artery downstream.
Carotid or vertebral arteries do not usually get blocked and only a small bit of blood will leak into the brain. The decrease of blood flow to the brain deprives cells of nutrients and can lead to dysfunction. When part of the brain does not function a stroke can occur. When a stroke happens, an area is cut off from blood almost entirely and the cells can die within five minutes. The ischemic penumbra goes around the core of dead cells and is made up of cells that are still alive but do not actually function. This is referred to as idling cells and they can live for around three hours.
An ischemic stroke can be treated by the restoration of blood flow to the brain. One treatment option is a tissue plasminogen activator which has to be done within a three hour time from the start of the symptoms. Only 3-5% of patients make it in time for this course of treatment. This treatment increases the risk for a brain hemorrhage and cannot be used on a hemorrhage stroke. Carotid endarterectomy or the stenting of the cervical and intracranial vessels can also help to decrease recurrent strokes.
The Merci Retriever is a device in the shape of a corkscrew that works to take out blood clots from the arteries of patients with a stroke. The patient will have a small incision made in the groin and a catheter is placed up to the neck arteries. Another catheter in the neck will be guided to reach the blood clot and the Merci Retriever coils into a corkscrew shape and is pulled into the clot. A balloon will inflate in the artery to cut off blood flow as the device pulls the clot out of the brain.
Hemorrhagic Stroke
Hypertension, a ruptured aneurysm, or a vascular malformation can cause a hemorrhagic stroke. An intracerebral hemorrhage happens when there is a bleed in brain tissue and a blood clot in the brain. A subarachnoid hemorrhage happens when the bleeding fills into the CSF spaces in the brain.
These strokes usually need surgery performed to take away the pressure in the skull.
Endovascular treatment inserts a long flexible tube called a catheter into a major artery. This artery is typically in the thigh and the catheter is guided into the aneurysm and inserts stents into the blood vessel to prevent further damage and strokes.
Recovery and rehab are crucial to the treatment of strokes. Sometimes undamaged areas of the brain can regain lost functions. This can include speech therapy, physical therapy, or OT.
It is important to seek medical care as soon as the stroke happens.
Transient Ischemic Attack (TIA)
A transient Ischemic Attack does not leave permanent damage. Usually an artery to the brain gets blocked and causes stroke symptoms but the blockage will only be temporary. Symptoms of TIA are similar to a stroke but do not last long. This includes:
- Sudden numbness or weakness in face, arm, leg
- Confusion or speak issues
- Trouble walking, dizziness
- Sudden and severe headaches
There is no treatment for TIA but it should be identified to prevent another attack. Around 30% of people who have a major stroke will have TIA beforehand and 10% of TIA victims will have a stroke within two weeks. Get medical care as soon as possible.
RISK FACTORS
Strokes happen the most often in older adults but they can occur to anyone of any age. Stroke prevention can help lower risk of damage from a stroke. Here are some risk factors for strokes:
- Smoking: Smoking will increase risk
- High Blood Pressure: Blood pressure of 140/90 mm Hg or higher increase risk for stroke
- Carotid or artery disease: Plaque build up in the carotid artery can increase risk
- Diabetes: Diabetes increases risk
- Highblood cholesterol: 240 mg/dl or higher puts one at risk for heart disease which increases the risk of a stroke
- Obesity: This can lead to high blood pressure, high blood cholesterol, diabetes, heart disease, stroke
It has been studied that hormone replacement therapy (HRT) can increase the risk of stroke by 29%.
Risk factors that are uncontrollable:
- Age
- Gender: men are more likely to get strokes than women
- Heredity/race: Stroke risk can be heredity. African Americans are at a greater risk to stokes
- Prior stroke or heart attack: Having one stroke or heart attack puts one at risk of having a stroke.
CAROTID STENOSIS
The carotid arteries can have plaque of fat and cholesterol buildup and block the oxygen rich blood flow to the brain. This is atherosclerosis. Carotid stenosis is a makoy blockage of the carotid artery. This can lead to a TIA.
Carotid stenosis does not usually present symptoms but it can be detected by a doctor while listening to the carotid arteries with a stethoscope. Motor and sensory defects can occur due to the blockage. If a stenosis is suspected, a Doppler ultrasound, carotid duplex, or cerebral angiography may be recommended.
MEDICAL TREATMENT
Depending on how severe the narrowing is, the treatment will vary. If the artery has been narrowed by less than 50% then medication is the first treatment option to prevent a stroke. THis can include antihypertensive to control high blood pressure, medicine to decrease cholesterol, or anticoagulants as blood thinners to decrease clotting.
Surgery
A carotid endarterectomy can be performed by a neurosurgeon. An incision is made in the carotid artery and the surgeon dissects the plaque. The artery is widened to promote blood flow then the artery is repaired with sutures or by a graft. The surgery is around two hours and for a few days after surgery the patient may have pain near the incision or some difficulty swallowing. The patient can usually go home after one or two days and go to work within a month. Try not to drive or do physical activities for multiple weeks post operation.
Carotid Angioplasty and Stenting
This is a good option for patients who are not able to undergo surgery. This is an operation where a small mesh, metal tube is put inside the carotid artery to increase blood flow. The stent is put in after an angioplasty which the doctor uses a balloon tipped catheter to widen the plagued artery. The stent prevents the artery from closing up once the surgery is done.
CEREBRAL ANEURYSM
A cerebral aneurysm results when there is a weakened blood vessel in that brain that leads to a ballooning out of part of the wall of the vessel. Typically an aneurysm will develop where the blood vessel branches as this is a vulnerable area. This may be a congenital condition or can arise from other underlying conditions like high blood pressure or atherosclerosis or trauma to the head.
Aneurysms can happen at any age but as patients pass the age of 35 the risk slowly increases as well. Aneurysms happen most in people over the age of 50 and they also happen three times more often in women. The outcome is usually better for patients who receive treatment before the aneurysm has ruptured.
An MRA or a carotid angiogram can detect a cerebral aneurysm. A CT scan or a lumbar puncture can detect a rupture. A formal cerebral angiography should be done if an aneurysm is suspected.
Some warning symptoms of a ruptured aneurysm include headaches, nausea, vomiting, stiffness in the neck, blurred vision, light sensitivity, sensation loss. Most people have no symptoms for unruptured aneurysms though. Signs of an unruptured aneurysm include cranial nerve palsy, dilated pupils, double vision, pain above and behind the eye, headaches.
Brain bleeding may result from a ruptured aneurysm which can cause a subarachnoid hemorrhage. Blood may also leak into CSF areas or areas around the brain and lead to an intracranial hematoma. Blood can aggravate and damage brain cells. This can lead to body impairments or mental impairments. Bleeding in the brain can also lead to a coma, paralysis, or brain damage. There is a 50% rate of death after a ruptured aneurysm.
Surgery
A craniotomy opens the skull to perform surgery to clip an aneurysm. The surgeon will use clips to deflate the aneurysm and isolate it from the bloodstream. Cerebral aneurysms may be in parts of the brain too dangerous to perform surgery on. An angiography can be used to see the closure of an aneurysm and to preserve normal blood flow levels in the brain.
Endovascular therapy is a less invasive technique that does not require an operation. Micro catheters can deliver coils to the enlarged blood vessels that close up the aneurysm from inside of the blood vessel. A tiny balloon catheter holds the coil in place and a combination stent and coiling procedure using a small mesh tube to provide a scaffold for the coiling.
Patients should be treated as soon as possible if they have a ruptured aneurysm. Surgical risks will vary based on the aneurysm as well as the surgical procedure.
Postsurgical complications may include vasospasm and hydrocephalus. A sudden constriction of a blood vessel that decreases the flow of blood is a vasospasm. Hydrocephalus is when CSF builds up in the ventricles of the brain and increases pressure within the brain.
VASCULAR MALFORMATIONS
A vascular malformation is an abnormal connection between an artery or a vein. Vascular malformations are created as the blood vessels in the brain develop during pregnancy but the cause is not known.
Arteriovenous malformations (AVMs)
An AVM is a tangle of blood vessels that are abnormal and have a higher rate of bleeding. AVMs can happen anywhere in the body but brain AVMs are very risky.
WIth the use of an MRI and angiography, an AVM may be diagnosed. They can aggravate the surrounding brain and cause seizures and headaches. AVMs can grow bigger and rupture if they are not treated. THis can lead to a hemorrhage and brain damage that is permanent. 4% of people with an AVM will have a hemorrhage.
Treatment is done to try to get rid of the lesion but in the lowest risk way. Three treatment options include removing the AVM with microsurgery, stereotactic radiosurgery, and embolization. Some AVMs may benefit from a combination of treatments.
Stereotactic radiosurgery is a minimally invasive treatment that applies radiation through computer guidance to the AVM. This causes abnormal blood vessels to close off. This surgery only works on lesions that are 3.5 cm in diameter. It can also take nearly two years to get rid of the lesion.
Using neuroendovascular techniques to guide catheters into small cerebral vessels to feed the AVM is embolization. Glue or particles can be injected to the AVM or the arteries that feed the AVM. Neuroendovascular therapy can make a safer removal of an AVM or the AVM can be reduced in size by radiosurgery.
Mayomama Disease
This is a disease of the carotid arteries that is progressive and the branches can lead to permanent blockage. It affects the japanese population the most often. It also affects people around the age of 40 years. Children with this disease may get strokes, TIAs, cognitive impairments, seizures, or involuntary movements in the extremities. Adults may experience an intracranial hemorrhage more often from this disease.
The most common surgeries done for this disease include EDAS, EMS, STA-MCA, and multiple burr holes.
The EDAS procedure diseacts a scalp artery over several inches and then a temporary opening in the skull is made underneath the artery. The artery is sutured to the surface of the brain and the bone is also replaced.
In EMS surgery the temporalis muscle is dissected and placed onto the brain surface through a hole in the skull.
The STA-MCA procedure involves a scalp artery being sutured to a brain surface artery. Multiple burr holes are put in the skull for new vessels to grow into the brain from the scalp.
VENOUS ANGIOMAS
Patients who have venous angiomas may present with headaches or seizures but are usually not presented with symptoms. Treatment is not usually needed since venous angiomas do not bleed often. This condition affects about 2% of the population.
VEIN OF GALEN MALFORMATION
The Vein of Galen malformation is quite rare. It is sometimes found during prenatal testing or when infants have heart failure. A VGM is an abnormal connection between arteries and the veins that are deep draining in the brain. This occurs during embryonic development. These arteries and veins are connected to capillaries that work to slow blood flow to the brain to allow for a proper exchange of oxygen and nutrients in normal conditions.
A VGM is unlikely to rupture or bleed since it has thick walls. The VGM does not have capillaries and blood can flow very fast and put stress on the heart and lead to heart failure. It is important the children are diagnosed early to get early treatment. VGMs are usually treated with embolization.
