Preparing for Brain Tumor Surgery

Whenever someone in the family is diagnosed with a 'Brain Tumor', it causes a lot of apprehension in in the family. Surgery is usually the first step in treating most benign and many malignant tumors. It is often the preferred treatment when a tumor can be removed without unnecessary risk of neurological damage.

Surgery might be recommended to: 
• Remove as much tumor as possible
• Provide a tumor tissue sample for an accurate diagnosis and for genomic testing
• Remove at least part of the tumor to relieve pressure inside the skull (intracranial pressure), or to reduce the amount of tumor to be treated with radiation or chemotherapy
• Enable direct access for chemotherapy, radiation implants or genetic treatment of malignant tumors • Relieve seizures (due to a brain tumor) that are difficult to control with medications

“Radiosurgery” is a type of intense radiation delivered to a tumor. It may be used instead of, or in addition to, conventional surgery. Radiosurgery is not surgery in the conventional sense, as no opening is made in the skull. In certain cases, it may offer similar benefit and lower risk or discomfort than conventional surgery.

Before surgery your doctor will consider the following: 

• Location of the tumor. Where the tumor is located will determine whether it is operable or inoperable.

• Diagnosis and size of tumor. If a tumor is benign, does not cause intracranial pressure (due to its small size) or cause problems with sensitive areas, avoiding or postponing surgery might be considered.

• Number of tumors. The presence of multiple tumors creates additional challenges to safe removal.

• The borders, or edges, of the tumor. If the tumor is poorly defined around the edges, it may be mixed with normal brain tissue and more difficult to remove completely.

• Your general health. Are your heart, lungs, liver and overall general health strong enough to endure the strains of surgery? If this is a metastatic brain tumor (one which began as a cancer elsewhere in your body), is the primary cancer controlled?

• Your neurological status. Do you have symptoms of increased intracranial pressure? Are there signs of nerve damage possibly caused by the tumor? If so, further evaluation may be needed before surgery is attempted.

• Previous surgery. If you’ve had recent surgery, it is usually necessary to recover from the previous procedure before going through another one.

• Other options. Is it likely that another treatment would provide equal or better results at comparable or lower risk? Your doctor will take these points into consideration in forming your treatment plan.

WHAT IS AN “OPERABLE TUMOR?” 

An operable tumor is typically one that your doctor believes can be surgically removed with minimal risk of brain damage.

WHAT IS AN “INOPERABLE TUMOR?” 

In some cases surgery may not be possible because the tumor is so deep within the brain that it is not accessible without excessive risk of brain damage. Tumors located in the brain stem and thalamus are two examples. Other tumors may present a problem if located near a sensitive area in the brain that controls language, movement, vision or other important functions. However, with advances in technology, the so called 'INOPERABLE TUMORS" can also not be safely resected with minimal damage to the surrounding brain.

Highly sensitive scans are used for this purpose and may include:
 • Computerized Tomography (CT)
• Magnetic Resonance Imaging (MRI)
• Magnetic Resonance Spectroscopy (MRS)
• Positron Emission Tomography (PET)

Diffusion Tensor Imaging MRI’s may be used to generate maps of the nerve pathways called “fiber tracking.” Use of fiber tracking may help the surgeon avoid disrupting important nerve connections within the brain itself. Vital areas can also be defined by a procedure called brain mapping. At the beginning of the surgery, tiny electrodes are placed on the outer layer of the brain. Stimulating these electrodes helps the neurosurgeon determine the functions of those sensitive parts of the brain so they can be avoided during surgery.

WHAT TYPE OF SURGERY MIGHT BE RECOMMENDED?

CRANIOTOMY 
A craniotomy is the most common type of surgery to remove a brain tumor. “Crani” means skull and “otomy” means cutting into. The procedure typically involves shaving a portion of the head, making an incision in the scalp, then using specialized medical tools to remove a portion of the skull. This enables the neurosurgeon to find the tumor and remove as much as possible. After the tumor is removed, the portion of skull that was cut out is replaced, and the scalp is stitched closed. Remember, all of this is done with drugs that relax you or put you to sleep. They also numb the scalp and other tissues. The brain itself does Sample of a head frame used during stereotactic biopsy Electra, LSS frame not “feel” pain, so brain surgery can be done with you awake if the surgeon believes it is necessary to minimize the risk of the procedure.

CRANIECTOMY 
A craniectomy is similar to a craniotomy in all ways except one. While “otomy” means cutting into, “ectomy” means removal. In a craniectomy the bone removed for access to the brain is not replaced before closing the incision. The neurosurgeon may perform a craniectomy if he or she expects swelling to occur following surgery, or if the skull bone is not reusable. When the bone is reusable it can be replaced at a later date when it will not cause additional pressure. The skull piece is stored by the medical facility until a time when it might be reused. If a craniectomy is done, you will receive instructions from your health care team for protecting the soft spot created by the missing bone.

STEREOTACTIC BIOPSY
A Stereotactic biopsy. The same procedure as a needle biopsy but performed with a computer-assisted guidance system that aids in the location and diagnosis of the tumor.

TRANSPHENOIDAL SURGERY 
Transphenoidal surgery is an approach often used with pituitary adenomas and craniopharyngiomas. The term “trans” means through and “sphenoid” refers to the sphenoid bone located under the eyes and over the nose. The entry point for the neurosurgeon is through an incision made under the upper lip and over the teeth or directly through the nostril.

EMBOLIZATION 
If a tumor has a large number of blood vessels, surgery can be difficult due to the bleeding that could result. Embolization is a technique neurosurgeons use to stop the blood flow to the tumor prior to removing it. A diagnostic test, called an angiogram, is performed to determine if a significant amount of blood is going to the tumor. If so, the neurosurgeon or neuroradiologist can insert a small “plug” made of wire or glue-like material into the vessel. This stops the blood flowing to the tumor, but not to normal parts of the brain. Tumor removal usually follows within a few days. This technique might also be used with tumors that contain a high number of blood vessels – referred to as “vascular” or “well-vascularized” tumors. Meningiomas, meningeal hemangiopericytomas and glomus jugulare tumors are typically well-vascularized tumors.

WHAT ARE THE COMMON RISKS OF BRAIN TUMOR SURGERY? 
Brain tumor surgery poses both general and specific risks. The general risks apply to anyone going through surgery for any reason and are not limited to brain tumor surgery. These include:
• Infection
• Bleeding
• Blood clot formation (hematoma)
• Blood pressure instability
• Seizures
• Weakness
• Balance/coordination difficulties
• Memory or cognitive problems
• Spinal fluid leakage
• Meningitis (infection causing inflammation of membranes covering the brain and spinal cord)
• Brain swelling
• Stroke
• Hydrocephalus (excessive fluid in the brain)
• Coma
• Death

Risks specific to brain tumor surgery depend greatly on the particular location of the tumor. Particular areas of the brain control functions such as vision, hearing, smell, movement of the arms and legs, coordination, memory, language skills, and other vital functions. The process of operating on the brain always includes some risk that nerves or blood vessels serving these areas will be damaged. This could result in partial or complete loss of sensation, vision, movement, hearing or other functions. When a tumor is located deep within the brain it increases the risk and range of possible complications.

HOW LONG WILL IT TAKE FOR ME TO RECOVER FROM SURGERY? 
Any type of surgery is a trauma to your body. Some people will recover faster than others. While there is no “normal” recovery period that applies to all people, your recovery time will depend on:
• The procedure used to remove your brain tumor
• The part of your brain where the tumor was located
• The areas of your brain affected by the surgery
• Your age and overall general health

Ask your neurosurgeon what you can expect as a reasonable recovery time. This will help you set realistic goals for yourself in the weeks following surgery.

Please send your queries to mumbaistrokecare@gmail.com

Apps for Stroke Survivors - Apps for Aphasia Part - 2

The first part of the article was published earlier at 

Apps for Stroke Survivors Part 1


Text-to-Speech Apps Apps -  

Verbally (Free) - Has basic words programmed and the ability to speak a specific message based on typed in words. Verbally provides text to speech through its onscreen keyboard, word bank and phrase banks, though to customise these banks you need to upgrade for a price.

iSpeech: (Free) Type in text and listen with the iSpeech App.

Speak It: ($1.99) This app lets you enter text into your iPhone and then have the application say it back to you using a number of different voices. You can select between male and female American accents or rather posh sounding male and female British accents instead. You simply select the accent using a roller deck-style menu and then tap in what you want it to say in the box above it.lets you enter text into your iPhone and then have the application say it back to you using a number of different voices. You can select between male and female American and British accents. 

Predictable: ($159.99) This is a text based Augmentative and Alternative Communication (AAC) app designed to give a voice to someone who is unable to use their own. The app is most useful for people who have good cognitive abilities but have lost the ability to speak due to a variety of reasons such as Motor Neurone Disease, ALS, Cerebral Palsy, a head injury or a stroke.

TalkPath News (Free): Lingraphica’s TalkPath™ News is an online news source for individuals who need help reading, listening or comprehending daily news.

Assistive Express: This is an affordable Augmentative Alternative Communication (AAC) Device, catered to people with difficulty in speech. Assistive Express is designed to be simple and efficient, allowing users to express their views and thoughts at the most express manner, with natural sounding voices.

Apart from the ones listed above, Speech Magnet and Voice Dream Recorder are other Apps that can help patients with aphasia

Alternative and Complimentary treatments for Stroke

Stroke is one of the leading causes of disability and death in India and across the world. Correct identification and treatment within the 'golden hour' using clot busting medicines and/or clot removal techniques can reverse or limit the disability caused by acute stroke. Stroke prevention focusses on life-style modification, healthy diet, exercise and elimination/control of risk factors.

A number of alternative therapies/treatments have been suggested in literature for prevention of stroke. However, there is NO EVIDENCE that any of these helps in the prevention or treatment of stroke.

Herbal Medicines for Stroke

1. Ginkgo Biloba (Marathi - Ginko, Jinko)

Ginkgo biloba is used both to prevent and treat stroke. It helps to prevent blood clots from developing and increases blood flow to the brain. This herb has also been shown to inhibit free-radical formation. Ginkgo is widely used in Europe to treat complications of stroke, including memory and balance problems, vertigo and disturbed thought processes. 

2. Garlic (Marathi/Hindi - Lasun)

Garlic helps prevent ischemic stroke in three ways:

• Garlic reduces blood pressure

• Garlic lowers cholesterol levels

• Garlic is an anticoagulant.

Garlic is the best anti-clotting herb. It contains nine anticoagulant compounds. It is a major herb for heart attack prevention because of its blood-thinning effect and its ability to help control high blood pressure. These same effects also help prevent ischemic stroke

3. Ginger (Zingiber officinale) (Marathi - Ala; Hindi - Adrak)

Ginger is a cardiac tonic, as it decreases cholesterol and helps poor circulation. Ginger prevents blood from clotting excessively.

 4. Turmeric (Cucurma longa) (Marathi - Halad; Hindi - Haldi)

Many studies show that the compound curcumin, which is found in turmeric, helps prevent the formation of blood clots. 

5. Carrot (Marathi/Hindi - Gajar)

In a Harvard study of 87,245 female nurses, consumption of carrots (and to a lesser extent, spinach) significantly reduced stroke risk. Carrots are rich in beta-carotene and other carotenoids. Other studies show that people can reduce their risk of stroke by as much as 54 percent if they eat lots of fruits and veggies that are rich in beta-carotene and vitamins C and E.

6. Pigweed (Amaranthus) (Marathi - Cavaḷī; Hindi - Chaulaee)

A six-year Harvard study of more than 40,000 health professionals showed that compared with those who consumed the least calcium, those who got the most had just one-third the risk of succumbing to heart attack. Pigweed is an excellent plant source of calcium

7. Spinach (Marathi/Hindi - Paalak)

Studies at Tufts University in Boston and the University of Alabama in Birmingham have demonstrated that folate can help prevent both heart disease and stroke. Compared with people who consumed little folate, those who ingested the most were only half as likely to show narrowing of the carotid artery, the artery that leads to the brain.Spinach, cabbage, endive, asparagus, papaya, okra and pigweed have folate.

8. English pea (Pisum sativum), Scurfy pea (Psoralea corylifolia) (Marathi/Hindi - Matar)

Nearly all legumes contain genistein, a cancer-preventive nutrient. In addition to guarding against cancer, genistein also appears to have a significant anti-clotting effect. So, it may also help prevent ischemic stroke and heart attack.

9. Willow (Marathi - Bĕṭa; Hindi - Vilo)

Willow bark is herbal aspirin, and a low-dose aspirin has been shown in several studies to reduce the risk of ischemic stroke by about 18 percent. (Low-dose aspirin also cuts heart attack risk by about 40 percent in men and 25 percent in women.)

10. Pineapple (Marathi/Hindi- Anaanaas)

Pineapple contains an enzyme known as bromelain that is best known for its ability to break down proteins. It's a key ingredient in meat tenderizers. But bromelain also has an anti-clotting action that might help prevent ischemic stroke and heart attack.

11. Bilberry (Vaccinium myrtillus) (Marathi/Hindi - bBooberee)

Bilberries, blueberries and huckleberries contain compounds known as anthocyanidins. European studies show that these compounds help prevent blood clots and also break down plaque deposits lining the arteries. 

12. Evening primrose

Evening primrose oil is rich in gamma-linolenic acid (GLA), which has potent anti-clotting and blood pressure­lowering actions. It is believed to be useful in the prevention of stroke and heart disease. Borage oil is also rich in GLA.

13. Astragalus (Hindi - Kitara)

Astragalus improves tissue oxygenation.

14. Calamus (Marathi - Vēkhaṇḍa; Hindi - Bach)

Calamus helps restore brain tissue damaged by stroke.

15. Cayenne Pepper (Hindi/Marathi - Laal Mirch)

Cayenne pepper improves circulation and heart function without raising blood pressure. 

16. Green Tea

Green tea may act as one of the most potent free-radical scavengers to protect against the peroxidation of lipids, a contributing factor in atherosclerosis.

17. Hawthorn (Hindi/Marathi - Nagaphani)

Hawthorn has been reported to prevent or slow the progression of arteriosclerosis.

18. Horsetail (Hindi - Ashwa Pucchha)

The silica in horsetail maintains the elastic connective tissue of the arteries. It promotes arterial impermeability to harmful lipids, preventing deposits.

19. Kava kava (Marathi/Hindi -Kŏphī)

Kava kava helps to protect the brain against oxygen deprivation. Do not use kava kava if you are pregnant or nursing, if you have Parkinson's disease, or if you are taking a prescription medication for depression or anxiety.

20. Pine-bark and Grape-seed Extract

Pine-bark and grape-seed extract are high in proanthocyanidins (also known as OPCs) that increase the structural strength of weakened blood vessels. 

For more scientific information on each of these herbs, please refer to the official website of the National Center for Complementary and Integrative Health (https://nccih.nih.gov/health/herbsataglance.htm)

Flow Diversion for Brain Aneurysms - Patient Guide

What is Flow Diversion?

It is a forma of treatment of brain aneurysms wherein a stent like device is placed in the portion of the artery from which the aneurysm arises. The flow diverter decreases the flow of blood within the aneurysm to the extent that the aneurysm is occluded.

How effective is Flow Diversion?

Results from many studies have shown that flow diversion is a safe and effective treatment for aneurysms, more so for unruptured aneurysms. Flow diversion removes the need to enter the aneurysm during surgery, which is the most dangerous part of endovascular treatment of aneurysms, according to medical experts. The risk of rupturing during surgery is greatly diminished by not placing a device inside the aneurysm.

What are the drawbacks of Flow Diversion treatment for brain aneurysms?

1. The aneurysm does not close immediately, thus, there is a small risk of rupture until the aneurysm closes
2. One has to be on blood thinner medications for 1-2 years or more
3. The treatment is expensive in India (as compared to simple coiling or surgical clipping)

What questions should I ask my doctor if he/she recommends flow diversion to treat my brain aneurysm?

First of all, not all aneurysms can be treated by Flow Diversion treatment. Ans, there is a considerable number of aneurysms that can be treated by surgical clipping or simple coiling. Following factors need to be considered while choosing flow diversion treatment for an aneurysm

1. Can the patient be on two blood thinners for 1-2 years (patients at risk of bleeding do not tolerate blood thinners well)
2. Can the aneurysm be treated effectively by surgical clipping or simple coiling?
3. Has the aneurysm ruptured or not?

What are the available Flow Diverting Devices in Indian market?

1. Pipeline Embolization Device (eV3, Medtronic)
2. Silk (Balt Extrusion, Montmorency, France)
3. Surpass (Stryker)
4. FRED (Microvention)

When Headache Isn't Just A Headache.....

Headaches are common and almost everyone has had one during the lifetime. In majority of the people, headache is not a bad omen and occurs due to common conditions such as stress, fatigue, lack of sleep, hormonal changes, hunger, medications and changes in weather. The three most common types of headaches are tension, migraine and sinus.

Tension Headache: It is the most common type of headache wherein there is a feeling of a tight band around the head. the pain is mild to moderate and diffuse with a sensation of tightness around the forehead or on the sides and back. Unlike migraine, tension headache is not associated with visual disturbances, nausea or vomiting and is not aggravated by physical activity.

Migraine: It is usually a severe throbbing or pulsating pain, usually on one side of the head and commonly associated with nausea, vomiting and extreme sensitivity to light and sound. Warning symptoms (aura) such as flashes of light, blind spots, difficulty speaking, tingling on one side of the face, arm or leg can occur before the onset of headache. Prodromal symptoms may include constipation, mood changes, food cravings, neck stiffness, increased thirst and urination and frequent yawning. A migraine attack may last from a few hours to 3 days followed by the postdromal phase wherein confusion, moodiness, dizziness, weakness and sensitivity to light and sound may occur.

Sinus headache: This headache is caused by infection of the sinuses (sinusitis). The sinuses are small air spaces in the skull, found behind the nose, eyes and cheeks. They open out into the nose, allowing mucus and other secretions to drain and air to circulate normally. A sinus headache is a constant, throbbing pain felt in the face (around the eyes, cheeks and forehead), usually only on one side. It tends to be at its worst in the morning and may get better as the day progresses. The pain may also get worse when you move your head, strain or bend down, and when you experience extreme changes in temperature (such as going from a warm room into freezing air outside). It can also spread to your teeth, upper jaw and other parts of your head.

When should a person with headache be evaluated further?

• Age - >40 years or <15 years at onset of new headache
• First, worst or headache that is different from usual headache 
• Progressive headache (over weeks)
• Persistent headache precipitated by cough, sneeze, bending or exertion
• Thunderclap headache (explosive onset)
• Additional features - Atypical or prolonged aura (>1 hour) 
• Aura occurring for the first time in woman on combined oral contraceptive 
• New onset headache in a patient with a history of cancer or HIV
• Red Eye or blurring of vision (Acute angle closure Glaucoma)
• Concurrent systemic illness
• Neurological signs
• Seizures
• Symptoms/signs of Giant Cell Arteritis (e.g. jaw claudication)

Intracranial Atherosclerosis

What is intracranial artery atherosclerosis?

Intracranial atherosclerosis is deposition of cholesterol and lipids in the wall of the arteries inside the brain. Similar to carotid stenosis in the neck, it is caused by a buildup of plaque in the inner wall of the blood vessels. This narrowing of the blood vessels causes decreased blood flow to the area of the brain that the affected vessels supply. 

There are three ways in which intracranial artery atherosclerosis can result in a stroke:

•       Plaque can grow larger and larger, severely narrowing the artery and reducing blood flow to the brain. Plaque can eventually completely block (occlude) the artery.

•       Plaque can roughen and deform the artery wall, causing blood clots to form and blocking blood flow to the brain.

•       Plaque can rupture and break away, traveling downstream to lodge in a smaller artery and blocking blood flow to the brain.

What are the symptoms?

The symptoms of intracranial artery atherosclerosis are a transient ischemic attack (TIA) or stroke, which can be described with the mnemonic FAST:

F: for facial weakness or droop, especially on one side

A: for arm or leg weakness, tingling, or numbness, especially on one side

S: for slurred speech

T: for time. It is essential to seek immediate medical attention if the above symptoms occur.

Symptoms of a TIA and stroke are similar. TIAs result when blood flow to the brain is temporarily interrupted and then restored. The symptoms typically last a couple of minutes and then resolve completely, and the person returns to normal. However, TIAs should not be ignored; they are a warning that an ischemic stroke and permanent brain injury may be impending.

What are the causes?

Atherosclerosis is a major cause of intracranial artery stenosis. It can begin in early adulthood, but symptoms may not appear for several decades. Some people have rapidly progressing atherosclerosis during their thirties, others during their fifties or sixties. Atherosclerosis begins with damage to the inner wall of the artery caused by high blood pressure, diabetes, smoking, and elevated LDL cholesterol. Other risk factors include obesity, heart disease, family history, and advanced age.

How is a diagnosis made?

Computed Tomography Angiography, or CT angiogram, is a noninvasive X-ray that provides detailed images of anatomical structures within the brain. It involves injecting a contrast agent into the blood stream so that arteries of the brain can be seen. This type of test provides the best pictures of both blood vessels (through angiography) and soft tissues (through CT). It enables doctors to see the narrowed artery and to determine how much it has narrowed.

Magnetic Resonance Angiography (MRA) is similar to the CT angiogram. Contrast dye is injected through an IV to visualize blood vessels in the neck.

Angiogram is a minimally invasive test that uses X-rays and a contrast agent injected into the arteries through a catheter in the groin. It enables doctors to visualize all arteries and veins in the brain. It carries a low risk of permanent neurologic complications. Beyond identifying the area of disease, angiography provides valuable information about the degree of stenosis and shape of the plaque.

Transcranial Doppler Ultrasound is a quick, inexpensive test used to measure the velocity of blood flow through blood vessels in the brain. This technique measures blood flow velocity by emitting a high-pitched sound wave from an ultrasound probe. Different speeds of blood flow appear in different colors on a computer screen. The more sluggish the blood flow, the greater the risk of stroke.

CT or MR Perfusion imaging is a noninvasive test that detects blood flow in the brain and is used in planning surgery. It involves injecting a contrast agent into the bloodstream so that doctors 1) can study how much blood flow is reaching the brain and 2) can determine which areas of the brain are most at risk of stroke.

What treatments are available?

The goal of treatment is to reduce the risk of stroke. Treatment options for intracranial atherosclerosis vary according to the severity of the narrowing and whether you are experiencing stroke-like symptoms or not. Patients are first treated with medication and are encouraged to make lifestyle changes to reduce their risk of stroke. Surgery is limited to patients whose symptoms do not respond to medication.

Medications

Blood thinner medications, also called anticoagulants (aspirin, Clopidogrel, Coumadin), allow the blood to pass through the narrowed arteries more easily and prevent clotting. Studies show that aspirin and Coumadin provide similar benefits. Because blood-thinners are associated with an increased risk of bleeding, patients may be monitored for abnormal bleeding. Aspirin has fewer side effects than Coumadin and is associated with a lower risk of bleeding or hemorrhage. Patients taking Coumadin must have their blood monitored periodically; patients taking aspirin and/or Plavix do not require monitoring.

Cholesterol-lowering medications help reduce additional plaque formation in atherosclerosis. These medications can reduce LDL (low-density lipoprotein) cholesterol by an average of 25 to 30% when combined with a low-fat, low-cholesterol diet.

Blood pressure medications (diuretics, ACE inhibitors, angiotensin blockers, beta blockers, calcium channel blockers, etc.) help control and regulate blood pressure. Because high blood pressure is a major risk factor of stroke, regular blood pressure screenings are recommended, along with taking your medication regularly.

Surgery / Endovascular Therapy

The aim of surgery is to prevent stroke by removing or reducing the plaque buildup and enlarging the artery to allow more blood flow to the brain. Surgical treatment is considered for patients whose symptoms do not respond to medication. For example, those who continue to have TIAs or strokes, those with a high grade of stenosis, and those with insufficient blood supply to an area of the brain.

Balloon angioplasty / stenting is a minimally invasive endovascular procedure that compresses the plaque and widens the diameter of the artery. Endovascular means that the procedure is performed inside the artery, from within the bloodstream, with a small flexible catheter. The catheter is inserted into the femoral artery in the groin during an angiogram. The catheter is then advanced through the bloodstream to where the plaque-narrowed artery is located. A small balloon is then slowly inflated within the narrowed artery to dilate it and compress the plaque against the artery wall.

The aim is to reduce stenosis by less than 50%, as a small increase of the vessel diameter results in large increases in blood flow to the brain. The balloon is then deflated and removed. In some cases, a self-expanding mesh-like tube called a stent is placed over the plaque, holding open the artery. Complications from angioplasty can include stroke, tearing of the vessel wall from the catheter or balloon, and vasospasm.

Angioplasty is typically recommended for patients who have high-grade artery stenosis (greater than 70%) and recurrent TIA or stroke symptoms despite medication treatment. Angioplasty / stenting can successful reduce the stenosis to less than 30% without complications in 60 to 80% of patients.

Cerebral artery bypass is a surgical procedure that reroutes the blood supply around the plaque-blocked area. This procedure requires making an opening in the skull, called a craniotomy. A donor artery from the scalp is detached from its normal position on one end, redirected to the inside of the skull, and connected to an artery on the surface of the brain. The scalp artery now supplies blood to the brain and bypasses the blocked vessel (see Cerebral Bypass Surgery). Complications from bypass can include stroke, vasospasm, and clotting in the donor vessel.

Bypass is typically recommended when the artery is 100% blocked and angioplasty is not possible. Results of artery bypass vary widely depending on the location and type of bypass. 

Despite treatment with medications, patients who have had a stroke or TIA due to intracranial artery stenosis face a 12 to 14% risk of recurrent stroke during the 2-year period after the initial stroke. In some high-risk groups, the annual risk of recurrent stroke may exceed 20%.

After angioplasty, restenosis can occur in 7.5 to 32.4% of patients and is usually not symptomatic. The long-term outcome of stroke prevention after angioplasty is not yet known, but short-term results are promising and is currently being studied in clinical trials.

It’s important to understand that atherosclerosis is a progressive disease. 

Lifestyle changes, medications help to prevent progression of the disease and occurrence of stroke. Surgery and Endovascular therapy are required in selected cases to prevent stroke.

Queries

In case of queries, please write to mumbaistrokecare@gmail.com

Management of Asymptomatic Carotid Artery Stenosis

Introduction

Asymptomatic stenosis of the carotid artery is not an uncommon finding encountered by many doctors in clinical practice.

The common question that comes up is

What is the management of these patients?

Should they undergo carotid revascularization surgery?

Current guidelines recommend revascularization in most patients with severe asymptomatic carotid artery stenosis. However, these guidelines are based on older studies that do not reflect the changing natural history of asymptomatic carotid artery stenosis with current optimal medical management.

Conventional treatment

Current recommendations for revascularization for asymptomatic carotid artery stenosis are predominantly based on two landmark studies performed in the 1990s.

The Asymptomatic Carotid Artery Study (ACAS) was a well-conducted study that assessed carotid endarterectomy (CEA) in asymptomatic carotid artery stenosis (>60%) for stroke prevention. The study was halted because of a projected safety favoring carotid endarterectomy (CEA). The perioperative stroke rate was 2.3%. The five-year projected rate of ipsilateral stroke was 11% for the medical group versus 5.1% for the surgical group.

In the Asymptomatic Carotid Surgery Trial (ACST), the 30-day risk of stroke or death was 3.1%. The five-year rates were 6.4% for CEA and 11.7% for medical therapy arm.

However, medical therapy in these trials was not up to current standards, with only a minority of patients receiving lipid-lowering therapy (Statins) and blood pressure (BP) was also significantly higher than today's standards.

Evolving Natural History of Asymptomatic Carotid Artery Stenosis

Recent evidence suggests that the natural history of asymptomatic carotid artery stenosis has improved remarkably, and the risk-benefit analysis of revascularization will need to be re-evaluated. Current optimal medical management consists of high-dose statin drugs, optimal BP control, smoking cessation, antiplatelet therapy (generally aspirin alone), optimal diabetes control and other lifestyle changes. Hence, the annual risk of stroke with current OMT is likely <1%.

Who is a "High-Risk" Patient?

The reality is that the majority of patients with asymptomatic carotid artery stenosis will never become symptomatic and may undergo unnecessary procedures if these studies do show benefit of endarterectomy or stenting

Clinical Features

There are few clinical predictors of increased stroke risk in asymptomatic carotid artery stenosis. Certain clinical characteristics, such as male sex, current smoking, poorly controlled hypertension, and history of contralateral transient ischemic attack (TIA)/stroke impart a higher risk of future stroke. However these are too non-specific to serve as useful guides for deciding about revascularization.

Stenosis Severity

Patients with 50-69% stenosis had a lower risk compared to those with 70-89% and 90-99% stenosis. However, stenosis severity alone is not a strong enough predictor to be used alone in decision making.

Progression of Stenosis

Progression of stenosis on periodic examination has been shown to impart at least twice the risk of stroke in patients.

Plaque Characteristics

Using ultrasound, atherosclerotic plaques can be characterized based on their surface irregularity, ulcerations, echolucency and gray-scale values. Studies show that patients with predominantly echolucent, lipid-rich plaque have significantly higher stroke risk (3%) than those with mostly echodense, fibrotic plaque (0.8-0.4%). Ulceration on plaque surface detected by three-dimensional ultrasound has also been shown to identify high-risk subjects. Magnetic resonance imaging (MRI) has also been used to detect the presence of intraplaque hemorrhage as indicative of a high-risk plaque. Intraplaque hemorrhage detected by MRI is associated with an increased risk of cerebrovascular events

Silent Emboli Detection

Since both progressive stenosis and high-risk imaging features identify unstable plaque more prone to atheroembolic events, another way to identify patients at risk is to assess for active silent emboli or evidence of prior asymptomatic cerebral emboli using transcranial doppler study. However, most patients with these signals did remain stroke free at three years, and thus, this test lacks the specificity for stand-alone clinical use.

Silent Embolic Infarcts on Computed Tomography (CT) or MRI

Presence of ipsilateral silent embolic infarcts on neuroimaging may be predictive of increased risk of ipsilateral stroke.

 Reduced Cerebrovascular Reserve

In patients with severe ipsilateral carotid stenosis, the presence of an incomplete circle of Willis or presence of intracranial or contralateral occlusive disease can reduce cerebral perfusion pressure. Cerebrovascular reserve in such patients can be assessed using TCD velocity measurements in response to acetazolamide or breathing 5% CO2.

Elderly

The elderly (especially those over 80 years of age) is a group in which the benefit of revascularization for asymptomatic carotid artery stenosis is most controversial because However, age cannot be an absolute contraindication with increasing life expectancy of the overall population; certainly in carefully selected patients, excellent outcomes after both CEA (Carotid Endarterectomy) and CAS (Carotid Artery Stenting) have been demonstrated. Overall CEA has more favorable outcomes for those over 70 years of age and CAS for those under 70 years of age.

Conclusions and Recommendations for Clinical Practice

Both medical and surgical management arms of asymptomatic carotid artery stenosis are rapidly evolving and will continue to result in decreased stroke risk.

• We recommend that for asymptomatic carotid artery stenosis patients (even those with >80%) stenosis there is enough evidence for a more conservative approach and decisions regarding revascularization should be made after discussing the stroke risk with the patients.
• Serial ultrasounds should be performed and revascularization offered to those with >70% stenosis with evidence of progression of stenosis severity.
• All patients with asymptomatic carotid artery stenosis should be on Optimal Medical Management.
• For the very elderly (>80 years) and life expectancy less than five years, a conservative approach is most reasonable in most situations.
• Carotid Endarterectomy remains the gold-standard for revascularization of carotid stenosis. Carotid Artery Stenting should be considered in patients with high risk of surgery from associated cardiac co-morbidity.
• Individual patient and anatomic risks for CEA and CAS are different and should be considered and a multi-specialty approach should be followed.