What is Cerebrovascular Disease?
A stroke, also known as a cerebrovascular accident (CVA), is a medical emergency that happens when blood flow to the brain is interrupted or a blood vessel in the brain ruptures. Roughly 85% of strokes are ischemic, meaning they are caused by a blockage, while the remaining 15% are hemorrhagic, caused by a bleed. This piece focuses mainly on ischemic strokes, which are usually due to blocked blood flow.
While the rate of strokes and stroke-related deaths has declined over the past few decades, it’s important to know that stroke is the leading cause of long-term disability worldwide. That’s why it’s essential to identify the signs of a stroke early and get quick treatment to limit the damage and improve recovery chances. There are multiple causes of stroke, with high blood pressure being the top one for ischemic stroke. Younger people can also have strokes due to a range of reasons like blood clotting disorders, carotid artery tears, and illegal drug use.
When dealing with a potential stroke, time is critical – every minute counts. The sooner a stroke is diagnosed and treated, the better the outcome. Therefore, a fast medical history intake and examination are vital. The strategies used to treat a stroke have improved significantly over the years. Presently, a clot-busting medication called intravenous tissue plasminogen activator (IV tPA) can be given within 4.5 hours of the onset of stroke symptoms, while a procedure called mechanical thrombectomy, which physically removes the clot, can be performed up to 6 hours after symptoms begin. Recent research, like the DAWN trial, has shown that the window for performing a mechanical thrombectomy can be expanded in selected severe cases to 24 hours after symptom onset.
What Causes Cerebrovascular Disease?
Strokes can be caused by different things, and these can be grouped into three types: embolic, thrombotic and lacunar. Common things that increase the risk of having a stroke include high blood pressure, diabetes, smoking, being overweight, an irregular heartbeat condition called atrial fibrillation, and using drugs. High blood pressure is the most common risk factor that we can control and is most frequent in African-Americans and often starts earlier in life.
It’s recommended that people who have had a stroke aim for a blood pressure lower than 140/90 mm Hg. Chronic high blood pressure that isn’t controlled properly can cause strokes in smaller vessels in specific parts of the brain, such as the internal capsule, thalamus, pons, and cerebellum.
Lifestyle changes such as losing weight, reducing salt intake, and eating more fruits and vegetables (like in the Mediterranean diet) can help lower blood pressure. For every 10 mm Hg decrease in blood pressure, the risk of stroke can be reduced by a third.
A third of adults in the USA have high levels of ‘bad’ cholesterol (low-density lipoprotein or LDL), which leads to the formation of plaque in the blood vessels inside the brain. Over time, this plaque build-up can lead to thrombotic strokes. In older people, the risk of a stroke caused by a clot, also known as cardioembolic stroke, mainly increases due to atrial fibrillation. The remaining 20% of strokes are hemorrhagic, or caused by bleeding. This bleeding could be due to high blood pressure, a ruptured aneurysm, blood vessel abnormalities, use of drugs like cocaine, bleeding from cancer metastasis, a disease called amyloid angiopathy, and other rare causes.
About 20% of all strokes caused by blocked blood flow, known as ischemic strokes, are lacunar strokes. These result from a blockage in small arteries supplying specific regions of the brain, and common causes are tiny clots, inflammation and death of artery wall cells due to conditions such as high blood pressure or vasculitis (a disease in which the body’s immune cells attack the blood vessels), amyloid angiopathy, and a condition called hyaline arteriosclerosis which causes the wall of blood vessels to become thickened and hard.
Risk Factors and Frequency for Cerebrovascular Disease
Stroke is a major cause of both death and disability. It ranks as the fifth leading cause of death in the United States, affecting around 800,000 people every year. Despite a decrease in the number of new cases, the harmful effects of stroke have increased due to longer life expectancies. Consequently, women, who generally have a longer lifespan, face a greater lifetime risk of experiencing a stroke. On a global scale, strokes cause at least 5 million deaths annually and leave millions of others with disabilities.
- Stroke is the fifth leading cause of death in the US and it affects approximately 800,000 people each year.
- It’s the primary cause of disability.
- The number of new stroke cases is decreasing, but its after-effects are increasing.
- Women have a higher risk of stroke over their lifetime due to their longer life expectancy.
- Worldwide, strokes lead to at least 5 million deaths every year and leave millions more disabled.
Signs and Symptoms of Cerebrovascular Disease
When a patient comes in with potential stroke symptoms, the doctor will first need to know when the symptoms started or when the person was last seen as normal. This information is vital, as it helps determine the patient’s eligibility for certain treatments like clot-busting drugs or procedures to remove the clot. Some other important information to gather includes whether the patient has any risk factors for heart disease or stroke like arteriosclerosis, diabetes, smoking habits, atrial fibrillation, drug abuse, migraine, seizures, infections, trauma, or pregnancy.
As quickly as possible, the medical staff need to monitor the patient’s vital signs, attach heart monitoring equipment, and set up an intravenous (IV) line. Simultaneously, the doctor will perform a quick examination to evaluate the patient’s brain function. This assessment often involves the use of a scale known as the National Institutes of Health Stroke Scale (NIHSS). The saying “time is brain” underlines the need for speed during this process. The doctor will need to examine:
- Consciousness level (i.e., is the patient alert and responsive, only responsive to painful stimuli, or unresponsive/comatose)
- Language skills (fluency, naming, comprehension, repetition)
- Dysarthria (speech slurring)
- Muscle strength (this can be tested with a simple task like a pronator drift)
- Visual field (presence of deficits)
- Eye movements (for any abnormalities, a preference for gazing more to one side often indicates a lesion on that side)
- Facial paralysis (this can be tested by asking the patient to smile)
- Ataxia (coordination issues, can be identified by the finger-to-nose test)
A careful history and physical exam can lead to the location of the stroke. Different types of strokes can show unique combinations of symptoms:
- Anterior Cerebral Artery (ACA) Infarction: These are rare due to this region having plenty of backup blood supply. When they do happen, they often lead to speaking difficulties, personality changes, and weakness and numbness on the opposite side of the body, specifically in the leg.
- Middle Cerebral Artery (MCA) Infarction: The MCA is particularly important, as blocking it can affect a large area. These strokes can cause numbness and weakness on the opposite side of the body, most notably in the arm and face, and problems with speech if the left side is affected or difficulties with attention if the right side is affected.
- Posterior Cerebral Artery (PCA) Infarction: The PCA mostly supplies blood to the occipital lobe and the thalamus. Strokes here usually cause vision loss in one half of the visual field, and they can also lead to extreme sleepiness, cognitive problems, sensory deficits, or denial of blindness.
- Cerebellar Infarction: These strokes often lead to lack of coordination, slurred speech, nausea, vomiting, or dizziness.
- Lacunar strokes: These strokes are due to blockages in small blood vessels deep within the brain. They often lead to issues in motor control, sensory processing, and coordination, but they typically do not impact memory, thinking, consciousness level, or speech.
Doctors often use the NIHSS scale to measure the severity of a stroke. This scale considers various functions like vision, consciousness level, sensation and neglect, motor function, cerebellar function, and language. A higher score on this scale usually hints at the blockage of a more significant blood vessel.
Testing for Cerebrovascular Disease
When a patient is suspected to have had a stroke, doctors first need to stabilize their airway, breathing, and circulation. This is often referred to as ensuring the patient’s ‘ABC’. After this, a quick and focused health history and examination will be conducted. This might be something like the NIHSS, or National Institutes of Health Stroke Scale, which checks how severe the stroke is. It’s done while the patient is also having an IV put in, being monitored for heart activity, and having blood tests taken.
Next, they will have a ‘stat’ (urgent) CT scan (which is a type of X-ray) of the head, without using any contrast dye. They might also have a CT angiography, which gives a picture of the blood vessels, and perfusion imaging, which shows how well blood is flowing in the brain. The phrase ‘time is brain’ is often used to explain how important speed is when treating a stroke because brain cells die quickly without blood. rtPA, a clot-busting medication, is also usually prepared during this imaging step, ready to be used quickly if no bleeding is seen on the CT scan.
As this process needs to be done quickly, only patients who get all these tests done within 4.5 hours can have rtPA, which can save lives. After the rtPA, the results of the CT angiography are looked at to see if the patient might benefit from endovascular therapy, which is a procedure done inside the blood vessels.
The first sign of stroke that a doctor may see on a CT scan is a high density area in a blood vessel, suggesting there is a clot there. This is most often seen in the middle cerebral artery (MCA), a large blood vessel in the brain. The CT perfusion scan can also show areas of the brain that have reduced blood volume and reduced transit time (the time it takes blood to travel through the brain), which can indicate a stroke.
An MRI scan, which uses magnetic fields to create pictures of the brain, can show changes suggesting a stroke, such as increased signal in areas where water molecules are not moving normally and changes in the amount of fluid in the brain.
Recent developments in stroke treatment have allowed doctors to use a procedure called endovascular thrombectomy (removing a clot from a blood vessel) up to 6 hours after stroke symptoms start. This procedure has been shown to be better than standard medical care in patients with a blocked large blood vessel in the brain, regardless of where the patient is located and other patient characteristics.
Furthermore, due to a trial called the DAWN trial in 2018, endovascular thrombectomy is now also being used for select patients up to 24 hours after stroke symptoms start. This development helps more patients to be treated.
All patients suspected of having a stroke should be started on an antiplatelet medicine, which helps prevent clots, and a statin, which lowers cholesterol levels, and be admitted for a full examination. Patient can often have high blood pressure after stroke, but this should not be treated overly aggressively. Patients will also need an electrocardiogram to check how the heart is working and blood tests to check their kidney function, red and white blood cells, heart health, clotting function, cholesterol levels and short-term blood sugar levels.
Further tests, including a heart ultrasound and monitoring of the heart’s electrical activity, as well as imaging of the blood vessels in the neck, are performed to figure out what caused the stroke.
Treatment Options for Cerebrovascular Disease
Patients who have had an acute ischemic stroke (sudden loss of blood flow to the brain) must be admitted for a detailed neurological assessment. Doctors will look into the source of the blood clot that may have caused the stroke, which includes evaluating the carotid artery and checking heart function. They’ll also check if the patient has any conditions that could increase the risk of stroke, like high cholesterol levels, diabetes, or certain heart diseases. Other tests may be run depending on the patient’s age and specific condition.
One standard treatment for a stroke is a medication called Alteplase (IV rtPA), which needs to be given within 4.5 hours of the start of the stroke. However, not everyone can receive this treatment. Certain age groups and those with specific health conditions or medical histories may not be eligible for this medication.
For some patients, doctors might consider a procedure called mechanical thrombectomy using a stent retriever. This involves removing the blood clot that’s blocking blood flow to the brain. The procedure is considered for patients who are in stable health prior to the stroke and can be treated within six hours of the stroke’s onset.
One potential risk with certain stroke treatments is a condition called hemorrhagic transformation, where there’s bleeding in areas of the brain damaged by the stroke. Several factors can increase the risk of this complication, including the location and size of the stroke, certain heart conditions, high blood sugar levels, low platelet count, and poor blood circulation in the brain.
Aspirin is usually given within a day or two of the stroke to help prevent further clots from forming, though the timing might change if the patient has received IV rtPA. Additionally, decisions about starting blood-thinning medications in patients with a heart condition known as atrial fibrillation (an irregular and often fast heartbeat) will depend on the extent of the stroke and whether there’s any bleeding in the brain.
Doctors may also recommend occupational therapy, physical therapy, and speech/swallow therapies depending on the patient’s needs. Additional support from primary care providers and neurologists will be arranged following hospital discharge.
In addition to addressing the stroke, doctors must also manage the patient’s other health conditions and monitor their temperature, blood sugar levels, and oxygen levels. Swelling in the brain can happen after a stroke, so doctors may use certain medications and management techniques to control this.
Seizures can occur in around 15% of stroke patients in the days following the stroke, and ongoing treatment may be needed for those who develop regular seizures.
Lastly, some patients may have severe and incapacitating strokes, and it’s important that medical teams involve the patient’s family in discussions on palliative care and end-of-life decisions when necessary.
What else can Cerebrovascular Disease be?
In diagnosing a stroke, doctors need to rule out other conditions that could show similar symptoms. These could include:
- Transient ischemic attack (TIA) – a temporary blockage of blood flow to the brain
- Hypoglycemia – low blood sugar levels
- Hyponatremia – low sodium levels in the blood
- Hemiplegic migraine – a rare type of migraine that causes temporary paralysis before or during a headache
- Encephalitis – inflammation of the brain
- Brain abscess – a collection of pus in the brain
- Cerebral neoplasm – a tumor in the brain
- Syncope – fainting or a sudden loss of consciousness
- Conversion disorder – a condition that causes physical symptoms that can’t be traced back to any physical disease
What to expect with Cerebrovascular Disease
Stroke remains a serious health issue with significant impact on quality of life. On a 1-year survival spectrum, 60-80% of stroke patients manage to survive. However, recovery is typically extended and there’s a high likelihood of experiencing another stroke. Following a stroke, majority of patients unfortunately retain some form of disability or partial neurological impairments, which often hinder their professional capabilities and ability to contribute to the workforce actively.
Possible Complications When Diagnosed with Cerebrovascular Disease
After a stroke, patients may face several complications. These can include a worsening of their neurological status due to the stroke extending or developing into a hemorrhage. Other complications can stem from prolonged inactivity and long hospital stays. Based on a multicenter study, here are possible complications that can happen after a stroke during the acute (initial) phase :
- Recurrent stroke – 9% of cases
- Epileptic seizure – seen in about 3% of patients
- Urinary tract infection – occurring in 24% of cases
- Pneumonia – experienced by 22% of patients
- Pressure sores – affect 21% of patients
- Deep venous thrombosis (blood clot in deep vein) – occurs in 2% of cases
- Pulmonary embolism (blood clot in the lungs) – found in 1% of patients
- Depression – seen in 16% of stroke patients
- Anxiety – experienced by 14% of patients
Preventing Cerebrovascular Disease
Avoiding strokes—which are either primary (the first stroke a person has) or secondary (strokes that happen after the first one)—is the main aim of the treatment. It’s very important to identify and help those at the highest risk as soon as possible. This help often involves advising lifestyle changes and managing other health conditions to stop a serious event like a stroke from happening. These other health conditions can include diabetes, high blood pressure, smoking, and irregular heart rhythm (atrial fibrillation). These are usually the diseases most often linked with strokes. However, some other conditions like vasculitis (a disease that inflames the blood vessels) and some autoimmune diseases (where the body’s own immune system attacks healthy cells) are also connected to vascular diseases, including stroke.
Doctors in primary care and specialized areas should take their time identifying these patients to provide tailored advice and aggressive treatment for these underlying diseases in order to prevent strokes.
The American Stroke Association recommends that people remember the acronym ACT FAST to help recognize the early signs of a stroke:
* F (Face) – If you see one side of a person’s face droop or their smile is uneven.
* A (Arms) – If a person’s arm feels numb or weak – You can check this by asking them to raise their arms.
* S (Speech difficulty) – If a person speaks in a slurred way or has trouble understanding speech.
* T (Time) – If any of the above signs are noticeable, even if they don’t last long, it’s time to call emergency services (911).
Other signs of a stroke that you should be aware of are:
* Suddenly feeling numb
* Suddenly feeling confused
* Suddenly having trouble seeing
* Suddenly having trouble walking
* Suddenly having a severe headache.
