A transient ischemic attack (TIA), commonly known as a mini-stroke, is a minor stroke whose noticeable symptoms usually end in less than an hour. TIA causes the same symptoms associated with strokes, such as weakness or numbness on one side of the body, sudden dimming or loss of vision, difficulty speaking or understanding language,
slurred speech
Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. In other words, it is a condition in which problems effectivel ...
, or
confusion
In medicine, confusion is the quality or state of being bewildered or unclear. The term "acute mental confusion"
.
All forms of stroke, including TIA, result from a disruption in blood flow to the
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...
. A TIA is caused by a temporary disruption in blood flow to the brain, or cerebral blood flow (CBF). The primary difference between a major stroke and the TIA's minor stroke is how much tissue death ( infarction) can be detected afterwards through medical imaging. While a TIA must by definition be associated with symptoms, strokes can also be symptomatic or silent. In silent stroke, also known as ''silent cerebral infarct'' (SCI), there is permanent infarction detectable on imaging, but there are no immediately observable symptoms. The same person can have major strokes, minor strokes, and silent strokes, in any order.
The occurrence of a TIA is a risk factor for having a major stroke, and many people with TIA have a major stroke within 48 hours of the TIA. All forms of stroke are associated with increased risk of death or
disability
Disability is the experience of any condition that makes it more difficult for a person to do certain activities or have equitable access within a given society. Disabilities may be cognitive, developmental, intellectual, mental, physical, s ...
. Recognition that a TIA has occurred is an opportunity to start treatment, including medications and lifestyle changes, to prevent future strokes.
Signs and symptoms
Signs and symptoms of TIA are widely variable and can mimic other neurologic conditions, making the clinical context and physical exam crucial in ruling in or out the diagnosis. The most common presenting symptoms of TIA are focal neurologic deficits, which can include, but are not limited to:
* Amaurosis fugax (painless, temporary loss of vision)
* One-sided
facial
A facial is a family of skin care treatments for the face, including steam, exfoliation (physical and chemical), extraction, creams, lotions, facial masks, peels, and massage. They are normally performed in beauty salons, but are also a ...
droop
* One-sided motor weakness
*
Diplopia
Diplopia is the simultaneous perception of two images of a single object that may be displaced horizontally or vertically in relation to each other. Also called double vision, it is a loss of visual focus under regular conditions, and is often ...
aphasia
Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in t ...
)
* Difficulty with articulation of speech (
dysarthria
Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. In other words, it is a condition in which problems effectivel ...
)
* Unsteady gait
* Difficulties with swallowing (
dysphagia
Dysphagia is difficulty in swallowing. Although classified under " symptoms and signs" in ICD-10, in some contexts it is classified as a condition in its own right.
It may be a sensation that suggests difficulty in the passage of solids or liqu ...
)
Numbness or weakness generally occur on the opposite side of the body from the affected hemisphere of the brain.
A detailed neurologic exam, including a thorough cranial nerve exam, is important to identify these findings and to differentiate them from mimickers of TIA. Symptoms such as unilateral weakness, amaurosis fugax, and double vision have higher odds of representing TIA compared to memory loss, headache, and blurred vision. Below is a table of symptoms at presentation, and what percentage of the time they are seen in TIAs versus conditions that mimic TIA. In general, focal deficits make TIA more likely, but the absence of focal findings do not exclude the diagnosis and further evaluation may be warranted if clinical suspicion for TIA is high (see "Diagnosis" section below).
TIA versus mimics
Non-focal symptoms such as amnesia, confusion, incoordination of limbs, unusual cortical visual symptoms (such as isolated bilateral blindness or bilateral positive visual phenomena), headaches and transient loss of consciousness are usually not associated with TIA, however patient assessment is still needed. Public awareness on the need to seek a medical assessment for these non-focal symptoms is also low, and can result in a delay by patients to seek treatment
Symptoms of TIAs can last on the order of minutes to one–two hours, but occasionally may last for a longer period of time. TIAs used to be defined as ischemic events in the brain that last less than 24 hours, but given the variation in duration of symptoms, this definition holds less significance. A pooled study of 808 patients with TIAs from 10 hospitals showed that 60% lasted less than one hour, 71% lasted less than two hours, and 14% lasted greater than six hours. Importantly, patients with symptoms that last more than one hour are more likely to have permanent neurologic damage, making prompt diagnosis and treatment important to maximize recovery.
Cause
The most common underlying pathology leading to TIA and stroke is a cardiac condition called atrial fibrillation, where poor coordination of contraction leads to a formation of a clot in the atrial chamber that can become dislodged and travel to a cerebral artery. Unlike in stroke, the blood flow can become restored prior to
infarction
Infarction is tissue death (necrosis) due to inadequate blood supply to the affected area. It may be caused by artery blockages, rupture, mechanical compression, or vasoconstriction. The resulting lesion is referred to as an infarct
(from the ...
which leads to the resolution of neurologic symptoms. Another common culprit of TIA is an atherosclerotic plaque located in the
common carotid artery
In anatomy, the left and right common carotid arteries (carotids) (Entry "carotid" in A portion of the plaque can become dislodged and lead to embolic pathology in the cerebral vessels.
In-situ
thrombosis
Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (thr ...
, an obstruction that forms directly in the cerebral vasculature unlike the remote embolism previously mentioned, is another vascular occurrence with possible presentation as TIA. Also, carotid stenosis secondary to atherosclerosis narrowing the diameter of the lumen and thus limiting blood flow is another common cause of TIA. Individuals with carotid stenosis may present with TIA symptoms, thus labeled symptomatic, while others may not experience symptoms and be asymptomatic.
Risk factors
Risk factors associated with TIA are categorized as modifiable or non-modifiable. Non-modifiable risk factors include age greater than 55, sex, family history, genetics, and race/ethnicity. Modifiable risk factors include cigarette
smoking
Smoking is a practice in which a substance is burned and the resulting smoke is typically breathed in to be tasted and absorbed into the bloodstream. Most commonly, the substance used is the dried leaves of the tobacco plant, which have bee ...
diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level (hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
,
hyperlipidemia
Hyperlipidemia is abnormally elevated levels of any or all lipids (fats, cholesterol, or triglycerides) or lipoproteins in the blood. citing: and The term ''hyperlipidemia'' refers to the laboratory finding itself and is also used as an umbr ...
, level of
carotid artery stenosis
Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis.
Signs and symptoms
The common carotid artery is the large artery whose pulse can be felt on both sides of the neck u ...
(asymptomatic or symptomatic) and activity level. The modifiable risk factors are commonly targeted in treatment options to attempt to minimize risk of TIA and stroke.
Pathogenesis
There are three major mechanisms of ischemia in the brain:
embolism
An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus may be a blood clot (thrombus), a fat globule (fat embolism), a bubble of air or other gas ( gas embolism), amniotic fluid ( a ...
traveling to the brain, in situ thrombotic occlusion in the intracranial vessels supplying the parenchyma of the brain, and
stenosis
A stenosis (from Ancient Greek στενός, "narrow") is an abnormal narrowing in a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture).
''Stricture' ...
of vessels leading to poor perfusion secondary to flow-limiting diameter. Globally, the vessel most commonly affected is the middle cerebral artery. Embolisms can originate from multiple parts of the body.
Common mechanisms of stroke and TIA:
Diagnosis
The initial clinical evaluation of a suspected TIA involves obtaining a history and physical exam (including a neurological exam). History taking includes defining the symptoms and looking for mimicking symptoms as described above. Bystanders can be very helpful in describing the symptoms and giving details about when they started and how long they lasted. The time course (onset, duration, and resolution), precipitating events, and risk factors are particularly important.
The definition, and therefore the diagnosis, has changed over time. TIA was classically based on duration of neurological
symptoms
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...
. The current widely accepted definition is called "tissue-based" because it is based on imaging, not time. The
American Heart Association
The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate cardiac care in an effort to reduce disability and death ...
and the American Stroke Association (AHA/ASA) now define TIA as a brief episode of neurological dysfunction with a
vascular
Blood vessels are the structures of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away from ...
cause, with clinical symptoms typically lasting less than one hour, and without evidence of significant
infarction
Infarction is tissue death (necrosis) due to inadequate blood supply to the affected area. It may be caused by artery blockages, rupture, mechanical compression, or vasoconstriction. The resulting lesion is referred to as an infarct
(from the ...
on
imaging
Imaging is the representation or reproduction of an object's form; especially a visual representation (i.e., the formation of an image).
Imaging technology is the application of materials and methods to create, preserve, or duplicate images.
...
.
Laboratory workup
Laboratory tests should focus on ruling out metabolic conditions that may mimic TIA (e.g. hypoglycemia causing altered mental status), in addition to further evaluating a patient's risk factors for ischemic events. All patients should receive a complete blood count with platelet count, blood glucose, basic metabolic panel, prothrombin time/ international normalized ratio, and
activated partial thromboplastin time
The partial thromboplastin time (PTT), also known as the activated partial thromboplastin time (aPTT or APTT), is a blood test that characterizes coagulation of the blood. A historical name for this measure is the kaolin-cephalin clotting time ( ...
as part of their initial workup. These tests help with screening for bleeding or
hypercoagulable
Thrombophilia (sometimes called hypercoagulability or a prothrombotic state) is an abnormality of blood coagulation that increases the risk of thrombosis (blood clots in blood vessels). Such abnormalities can be identified in 50% of people who ...
conditions. Other lab tests, such as a full hypercoagulable state workup or serum drug screening, should be considered based on the clinical situation and factors, such as age of the patient and family history. A fasting lipid panel is also appropriate to thoroughly evaluate the patient's risk for atherosclerotic disease and ischemic events in the future. Other lab tests may be indicated based on the history and presentation; such as obtaining inflammatory markers ( erythrocyte sedimentation rate and
C-reactive protein
C-reactive protein (CRP) is an annular (ring-shaped) pentameric protein found in blood plasma, whose circulating concentrations rise in response to inflammation. It is an acute-phase protein of hepatic origin that increases following interleukin ...
) to evaluate for giant cell arteritis (which can mimic a TIA) in those presenting with headaches and monocular blindness.
Cardiac rhythm monitoring
An electrocardiogram is necessary to rule out abnormal heart rhythms, such as atrial fibrillation, that can predispose patients to clot formation and embolic events. Hospitalized patients should be placed on heart rhythm telemetry, which is a continuous form of monitoring that can detect abnormal heart rhythms. Prolonged heart rhythm monitoring (such as with a
Holter monitor
In medicine, a Holter monitor (often simply Holter) is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring (the monitoring (medicine), monitoring of the electrical conduction system of the heart, electrical ...
or implantable heart monitoring) can be considered to rule out arrhythmias like paroxysmal atrial fibrillation that may lead to clot formation and TIAs, however this should be considered if other causes of TIA have not been found.
Imaging
According to guidelines from the
American Heart Association
The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate cardiac care in an effort to reduce disability and death ...
and American Stroke Association Stroke Council, patients with TIA should have head imaging "within 24 hours of symptom onset, preferably with magnetic resonance imaging, including diffusion sequences". MRI is a better imaging modality for TIA than computed tomography (CT), as it is better able to pick up both new and old ischemic lesions than CT. CT, however, is more widely available and can be used particularly to rule out intracranial hemorrhage. Diffusion sequences can help further localize the area of ischemia and can serve as prognostic indicators. Presence of ischemic lesions on
diffusion weighted imaging
Diffusion-weighted magnetic resonance imaging (DWI or DW-MRI) is the use of specific MRI sequences as well as software that generates images from the resulting data that uses the diffusion of water molecules to generate contrast in MR images. It ...
has been correlated with a higher risk of stroke after a TIA.
Vessels in the head and neck may also be evaluated to look for atherosclerotic lesions that may benefit from interventions, such as carotid endarterectomy. The vasculature can be evaluated through the following imaging modalities: magnetic resonance angiography (MRA), CT angiography (CTA), and
carotid ultrasonography
Carotid ultrasonography is an ultrasound-based diagnostic imaging technique to evaluate structural details of the carotid arteries. Carotid ultrasound is used to diagnose carotid artery stenosis (CAS) and can assess atherosclerotic plaque morp ...
/transcranial doppler ultrasonography. Carotid ultrasonography is often used to screen for carotid artery stenosis, as it is more readily available, is noninvasive, and does not expose the person being evaluated to radiation. However, all of the above imaging methods have variable sensitivities and specificities, making it important to supplement one of the imaging methods with another to help confirm the diagnosis (for example: screen for the disease with ultrasonography, and confirm with CTA). Confirming a diagnosis of carotid artery stenosis is important because the treatment for this condition, carotid endarterectomy, can pose significant risk to the patient, including heart attacks and strokes after the procedure. For this reason, the U.S. Preventive Services Task Force (USPSTF) "recommends against screening for asymptomatic carotid artery stenosis in the general adult population". This recommendation is for asymptomatic patients, so it does not necessarily apply to patients with TIAs as these may in fact be a symptom of underlying carotid artery disease (see "Causes and Pathogenesis" above). Therefore, patients who have had a TIA may opt to have a discussion with their clinician about the risks and benefits of screening for carotid artery stenosis, including the risks of surgical treatment of this condition.
Cardiac imaging can be performed if head and neck imaging do not reveal a vascular cause for the patient's TIA (such as atherosclerosis of the carotid artery or other major vessels of the head and neck). Echocardiography can be performed to identify
patent foramen ovale
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this do ...
Although there is a lack of robust studies demonstrating the efficacy of lifestyle changes in preventing TIA, many medical professionals recommend them. These include:
* Avoiding
smoking
Smoking is a practice in which a substance is burned and the resulting smoke is typically breathed in to be tasted and absorbed into the bloodstream. Most commonly, the substance used is the dried leaves of the tobacco plant, which have bee ...
* Cutting down on fats to help reduce the amount of plaque buildup
* Eating a healthy diet including plenty of fruits and vegetables
* Limiting
sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...
in the diet, thereby reducing blood pressure
* Exercising regularly
* Moderating intake of
alcohol
Alcohol most commonly refers to:
* Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom
* Alcohol (drug), an intoxicant found in alcoholic drinks
Alcohol may also refer to:
Chemicals
* Ethanol, one of sev ...
,
stimulants
Stimulants (also often referred to as psychostimulants or colloquially as uppers) is an overarching term that covers many drugs including those that increase activity of the central nervous system and the body, drugs that are pleasurable and inv ...
, sympathomimetics, etc.
* Maintaining a healthy weight
In addition, it is important to control any underlying medical conditions that may increase the risk of stroke or TIA, including:
* Hypertension
* High cholesterol
* Diabetes mellitus
* Atrial fibrillation
Treatment
By definition, TIAs are transient, self-resolving, and do not cause permanent impairment. However, they are associated with an increased risk of subsequent ischemic strokes, which can be permanently disabling. Therefore, management centers on the prevention of future ischemic strokes and addressing any modifiable risk factors. The optimal regimen depends on the underlying cause of the TIA.
Lifestyle modification
Lifestyle changes have not been shown to reduce the risk of stroke after TIA. While no studies have looked at the optimal diet for secondary prevention of stroke, some observational studies have shown that a Mediterranean diet can reduce stroke risk in patients without cerebrovascular disease. A Mediterranean diet is rich in fruits, vegetables and whole grains, and limited in red meats and sweets. Vitamin supplementation has not been found to be useful in secondary stroke prevention.
aspirin
Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat in ...
and
clopidogrel
Clopidogrel — sold under the brand name Plavix, among others — is an antiplatelet medication used to reduce the risk of heart disease and stroke in those at high risk. It is also used together with aspirin in heart attacks and following ...
, are both recommended for secondary prevention of stroke after high-risk TIAs. The clopidogrel can generally be stopped after 10 to 21 days. An exception is TIAs due to blood clots originating from the heart, in which case
anticoagulant
Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where t ...
s are generally recommended. After TIA or minor stroke, aspirin therapy has been shown to reduce the short-term risk of recurrent stroke by 60–70%, and the long-term risk of stroke by 13%.
The typical therapy may include aspirin alone, a combination of aspirin plus extended-release
dipyridamole
Dipyridamole (trademarked as Persantine and others) is a nucleoside transport inhibitor and a PDE3 inhibitor medication that inhibits blood clot formation when given chronically and causes blood vessel dilation when given at high doses over a ...
, or
clopidogrel
Clopidogrel — sold under the brand name Plavix, among others — is an antiplatelet medication used to reduce the risk of heart disease and stroke in those at high risk. It is also used together with aspirin in heart attacks and following ...
alone. Clopidogrel and aspirin have similar efficacies and side effect profiles. Clopidogrel is more expensive and has a slightly decreased risk of GI bleed. Another antiplatelet, ticlopidine, is rarely used due to increased side effects.
Anticoagulant medications
Anticoagulants may be started if the TIA is thought to be attributable to atrial fibrillation. Atrial fibrillation is an abnormal heart rhythm that may cause the formation of blood clots that can travel to the brain, resulting in TIAs or ischemic strokes. Atrial fibrillation increases stroke risk by five times, and is thought to cause 10-12% of all ischemic strokes in the US.
Anticoagulant
Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where t ...
therapy can decrease the relative risk of ischemic stroke in those with atrial fibrillation by 67%
Warfarin
Warfarin, sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pulmonary embolism, and to prevent ...
is a common anticoagulant used, but direct acting oral anticoagulants (DOACs), such as apixaban, have been shown to be equally effective while also conferring a lower risk of bleeding. Generally, anticoagulants and antiplatelets are not used in combination, as they result in increased bleeding risk without a decrease in stroke risk. However, combined antiplatelet and anticoagulant therapy may be warranted if the patient has symptomatic coronary artery disease in addition to atrial fibrillation.
Sometimes,
myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ...
("heart attack") may lead to the formation of a blood clot in one of the chambers of the heart. If this is thought to be the cause of the TIA, people may be temporarily treated with warfarin or other anticoagulant to decrease the risk of future stroke.
Blood pressure control
Blood pressure control may be indicated after TIA to reduce the risk of ischemic stroke. About 70% of patients with recent ischemic stroke are found to have hypertension, defined as systolic blood pressure (SBP) > 140 mmHg, or diastolic blood pressure (DBP) > 90 mmHg. Until the first half of the 2010s, blood pressure goals have generally been SBP < 140 mmHg and DBP < 90 mmHg. However, newer studies suggest that a goal of SBP <130 mmHg may confer even greater benefit. Blood pressure control is often achieved using
diuretic
A diuretic () is any substance that promotes diuresis, the increased production of urine. This includes forced diuresis. A diuretic tablet is sometimes colloquially called a water tablet. There are several categories of diuretics. All diuretics in ...
s or a combination of diuretics and angiotensin converter enzyme inhibitors, although the optimal treatment regimen depends on the individual.
Studies that evaluated the application of Blood pressure‐lowering drugs in people who had a TIA or stroke, concluded that this type of medication helps to reduce the possibility of a recurrent stroke, of a major vascular event and dementia. The effects achieved in stroke recurrence were mainly obtained through the ingestion of angiotensin-converting enzyme (ACE) inhibitor or a diuretic.
Cholesterol control
There is inconsistent evidence regarding the effect of LDL-cholesterol levels on stroke risk after TIA. Elevated cholesterol may increase ischemic stroke risk while decreasing the risk of hemorrhagic stroke. While its role in stroke prevention is currently unclear, statin therapy has been shown to reduce all-cause mortality and may be recommended after TIA.
Diabetes control
Diabetes mellitus increases the risk of ischemic stroke by 1.5-3.7 times, and may account for at least 8% of first ischemic strokes. While intensive glucose control can prevent certain complications of diabetes such as kidney damage and retinal damage, there has previously been little evidence that it decreases the risk of stroke or death. However, data from 2017 suggests that
metformin
Metformin, sold under the brand name Glucophage, among others, is the main first-line medication for the treatment of type 2 diabetes, particularly in people who are overweight. It is also used in the treatment of polycystic ovary syndrome. ...
semaglutide
Semaglutide, sold under the brand names Ozempic, Wegovy and Rybelsus, is an antidiabetic medication used for the treatment of type 2 diabetes and as anti-obesity medication for long-term weight management, developed by Novo Nordisk in 2012.
S ...
may reduce stroke risk.
Surgery
If the TIA affects an area that is supplied by the
stenosis
A stenosis (from Ancient Greek στενός, "narrow") is an abnormal narrowing in a blood vessel or other tubular organ or structure such as foramina and canals. It is also sometimes called a stricture (as in urethral stricture).
''Stricture' ...
, or narrowing, of the carotid artery. For people with extra-cranial carotid stenosis, if 70-99% of the carotid artery is clogged, carotid endarterectomy can decrease the five-year risk of ischemic stroke by approximately half. For those with extra-cranial stenosis between 50 and 69%, carotid endarterectomy decreases the 5-year risk of ischemic stroke by about 16%. For those with extra-cranial stenosis less than 50%, carotid endarterectomy does not reduce stroke risk and may, in some cases, increase it. The effectiveness of carotid endarterectomy or carotid artery stenting in reducing stroke risk in people with intra-cranial carotid artery stenosis is currently unknown.
In carotid endarterectomy, a surgeon makes an incision in the neck, opens up the carotid artery, and removes the plaque occluding the blood vessel. The artery may then be repaired by adding a graft from another vessel in the body, or a woven patch. In patients who undergo carotid endarterectomy after a TIA or minor stroke, the 30-day risk of death or stroke is 7%.Carotid artery stenting is a less invasive alternative to carotid endarterectomy for people with extra-cranial carotid artery stenosis. In this procedure, the surgeon makes a small cut in the groin and threads a small flexible tube, called a
catheter
In medicine, a catheter (/ˈkæθətər/) is a thin tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. Cat ...
, into the patient's carotid artery. A balloon is inflated at the site of stenosis, opening up the clogged artery to allow for increased blood flow to the brain. To keep the vessel open, a small wire mesh coil, called a stent, may be inflated along with the balloon. The stent remains in place, and the balloon is removed.
For people with symptomatic carotid stenosis, carotid endarterectomy is associated with fewer perioperative deaths or strokes than carotid artery stenting. Following the procedure, there is no difference in effectiveness if you compare carotid endarterectomy and carotid stenting procedures, however, endarterectomy is often the procedure of choice as it is a safer procedure and is often effective in the longer term for preventing recurrent stroke. For people with asymptomatic carotid stenosis, the increased risk of stroke or death during the stenting procedure compared to an endarterectomy is less certain.
People who undergo carotid endarterectomy or carotid artery stenting for stroke prevention are medically managed with antiplatelets,
statin
Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs.
L ...
s, and other interventions as well.
Prognosis
Without treatment, the risk of an ischemic stroke in the three months after a TIA is about 20% with the greatest risk occurring within two days of the TIA. Other sources cite that 10% of TIAs will develop into a stroke within 90 days, half of which will occur in the first two days following the TIA. Treatment and preventative measures after a TIA (for example treating elevated blood pressure) can reduce the subsequent risk of an ischemic stroke by about 80%. The risk of a stroke occurring after a TIA can be predicted using the ABCD² score. One limitation of the ABCD² score is that it does not reliably predict the level of carotid artery stenosis, which is a major cause of stroke in TIA patients. The patient's age is the most reliable risk factor in predicting any level of carotid stenosis in transient ischemic attack. The ABCD2 score is no longer recommended for triage (to decide between outpatient management versus hospital admission) of those with a suspected TIA due to these limitations.
Epidemiology
With the difficulty in diagnosing a TIA due to its nonspecific symptoms of neurologic dysfunction at presentation and a differential including many mimics, the exact incidence of the disease is unclear. It is currently estimated to have an incidence of approximately 200,000 to 500,000 cases per year in the US according to the
American Heart Association
The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate cardiac care in an effort to reduce disability and death ...
. TIA incidence trends similarly to stroke, such that incidence varies with age, gender, and different race/ethnicity populations. Associated risk factors include age greater than or equal to 60, blood pressure greater than or equal to 140 systolic or 90 diastolic, and comorbid diseases, such as
diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level (hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
atherosclerosis
Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually ...
, and atrial fibrillation. It is thought that approximately 15 to 30 percent of strokes have a preceding TIA episode associated.