Aortic dissection (AD) occurs when an injury to the
innermost layer of the
aorta
The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...
allows blood to flow between the layers of the aortic wall,
forcing the layers apart.
[ In most cases, this is associated with a sudden onset of severe chest or back pain, often described as "tearing" in character.][ Also, vomiting, ]sweating
Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals.
Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distri ...
, and lightheadedness
Lightheadedness is a common and typically unpleasant sensation of dizziness or a feeling that one may faint. The sensation of lightheadedness can be short-lived, prolonged, or, rarely, recurring. In addition to dizziness, the individual may feel ...
may occur.[ Other symptoms may result from decreased blood supply to other organs, such as stroke, lower extremity ischemia, or mesenteric ischemia.][ Aortic dissection can quickly lead to death from insufficient blood flow to the heart or complete rupture of the aorta.][
AD is more common in those with a history of ]high blood pressure
Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high b ...
; a number of connective tissue disease
A connective tissue disease (collagenosis) is any disease that has the connective tissues of the body as a target of pathology. Connective tissue is any type of biological tissue with an extensive extracellular matrix that supports, binds togeth ...
s that affect blood vessel wall strength including Marfan syndrome
Marfan syndrome (MFS) is a multi-systemic genetic disorder that affects the connective tissue. Those with the condition tend to be tall and thin, with long arms, legs, fingers, and toes. They also typically have exceptionally flexible joints a ...
and Ehlers–Danlos syndrome; a bicuspid aortic valve; and previous heart surgery. Major trauma, 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 ...
, cocaine
Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South Am ...
use, pregnancy
Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occurs by sexual intercourse, but ...
, a thoracic aortic aneurysm, inflammation of arteries, and abnormal lipid levels are also associated with an increased risk.[ The diagnosis is suspected based on symptoms with medical imaging, such as ]computed tomography
A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...
, magnetic resonance imaging, or ultrasound
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...
used to confirm and further evaluate the dissection.[ The two main types are Stanford type A, which involves the first part of the aorta, and type B, which does not.][
Prevention is by blood pressure control and smoking cessation.][ Management of AD depends on the part of the aorta involved.][ Dissections that involve the first part of the aorta (adjacent to the heart) usually require surgery.][ Surgery may be done either by an opening in the chest or from inside the blood vessel.] Dissections that involve the second part of the aorta can typically be treated with medications that lower blood pressure and heart rate, unless there are complications which then require surgical correction.[
AD is relatively rare, occurring at an estimated rate of three per 100,000 people per year.] It is more common in men than women.[ The typical age at diagnosis is 63, with about 10% of cases occurring before the age of 40.][ Without treatment, about half of people with Stanford type A dissections die within three days and about 10% of people with Stanford type B dissections die within one month.][ The first case of AD was described in the examination of King George II of Great Britain following his death in 1760.][ Surgery for AD was introduced in the 1950s by Michael E. DeBakey.][
]
Signs and symptoms
About 96% of individuals with AD present with severe pain that had a sudden onset. The pain may be described as a tearing, stabbing, or sharp sensation in the chest, back, or abdomen. About 17% of individuals feel the pain migrate as the dissection extends down the aorta. The location of pain is associated with the location of the dissection. Anterior chest pain is associated with dissections involving the ascending aorta, while interscapular back pain is associated with descending aortic dissections. If the pain is pleuritic in nature, it may suggest acute pericarditis
Pericarditis is inflammation of the pericardium, the fibrous sac surrounding the heart. Symptoms typically include sudden onset of sharp chest pain, which may also be felt in the shoulders, neck, or back. The pain is typically less severe when si ...
caused by bleeding into the sac surrounding the heart. This is a particularly dangerous eventuality, suggesting that acute pericardial tamponade
Cardiac tamponade, also known as pericardial tamponade (), is the buildup of fluid in the pericardium (the sac around the heart), resulting in compression of the heart. Onset may be rapid or gradual. Symptoms typically include those of obstruc ...
may be imminent. Pericardial tamponade is the most common cause of death from AD.
While the pain may be confused with that of a heart attack
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 m ...
, AD is usually not associated with the other suggestive signs, such as heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
and ECG changes. Less common symptoms that may be seen in the setting of AD include congestive heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
(7%), fainting (9%), stroke (6%), ischemic peripheral neuropathy
Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or or ...
, paraplegia
Paraplegia, or paraparesis, is an impairment in motor or sensory function of the lower extremities. The word comes from Ionic Greek ()
"half-stricken". It is usually caused by spinal cord injury or a congenital condition that affects the neu ...
, and cardiac arrest
Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possib ...
. If the individual fainted, about half the time it is due to bleeding into the pericardium, leading to pericardial tamponade. Neurological complications of aortic dissection, such as stroke and paralysis
Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 5 ...
, are due to the involvement of one or more arteries supplying portions of 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 ...
.
If the AD involves the abdominal aorta, compromise of one or both renal arteries
The renal arteries are paired arteries that supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle.
The renal arteries carry a large portion of total blood flow to the kidneys. Up t ...
occurs in 5–8% of cases, while ischemia of the intestines occurs about 3% of the time.
Blood pressure
People with AD often have a history of high blood pressure
Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high b ...
. The blood pressure is quite variable at presentation with acute AD. It tends to be higher in individuals with a distal dissection. In individuals with a proximal AD, 36% present with hypertension, while 25% present with hypotension
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...
. Proximal AD tends to be associated with weakening of the vascular wall due to cystic medial degeneration. In those who present with distal (Stanford type B) AD, 60–70% present with high blood pressure, while 2–3% present with low blood pressure
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...
.
Severe hypotension at presentation is a grave prognostic indicator. It is usually associated with pericardial tamponade, severe aortic insufficiency, or rupture of the aorta. Accurate measurement of blood pressure is important. Pseudohypotension (falsely low blood-pressure measurement) may occur due to involvement of the brachiocephalic artery (supplying the right arm) or the left subclavian artery (supplying the left arm).
Aortic insufficiency
Aortic insufficiency (AI) occurs in half to two-thirds of ascending AD, and the diastolic heart murmur of aortic insufficiency is audible in about 32% of proximal dissections. The intensity (loudness) of the murmur depends on the blood pressure and may be inaudible in the event of low blood pressure.
Multiple causes exist for AI in the setting of ascending AD. The dissection may dilate the annulus of the aortic valve, preventing the leaflets of the valve from coapting. The dissection may extend into the aortic root and detach the aortic valve leaflets. Alternatively, following an extensive intimal tear, the intimal flap may prolapse into the left ventricular outflow tract, causing intimal intussusception Intussusception may refer to:
* Intussusception (medical disorder)
Intussusception is a medical condition in which a part of the intestine folds into the section immediately ahead of it. It typically involves the small bowel and less commonly t ...
into the aortic valve, thereby preventing proper valve closure.
Myocardial infarction
Heart attack
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 m ...
occurs in 1–2% of aortic dissections. Infarction is caused by the involvement of the coronary arteries, which supply the heart with oxygenated blood, in the dissection. The right coronary artery is involved more commonly than the left coronary artery. If the myocardial infarction is treated with thrombolytic
Thrombolysis, also called fibrinolytic therapy, is the breakdown (lysis) of blood clots formed in blood vessels, using medication. It is used in ST elevation myocardial infarction, stroke, and in cases of severe venous thromboembolism (massi ...
therapy, the mortality increases to over 70%, mostly due to bleeding into the pericardial sac, causing cardiac tamponade.
Pleural effusion
A pleural effusion
A pleural effusion is accumulation of excessive fluid in the pleural space, the potential space that surrounds each lung.
Under normal conditions, pleural fluid is secreted by the parietal pleural capillaries at a rate of 0.6 millilitre per ...
(fluid collection in the space between the lungs and the chest wall or diaphragm
Diaphragm may refer to:
Anatomy
* Thoracic diaphragm, a thin sheet of muscle between the thorax and the abdomen
* Pelvic diaphragm or pelvic floor, a pelvic structure
* Urogenital diaphragm or triangular ligament, a pelvic structure
Other
* Diap ...
) can be due to either blood from a transient rupture of the aorta or fluid due to an inflammatory reaction around the aorta. If a pleural effusion were to develop due to AD, it is more common in the left hemithorax rather than the right hemithorax.
Causes
Aortic dissection is associated with hypertension (high blood pressure) and many connective tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tissue ...
disorders. Vasculitis
Vasculitis is a group of disorders that destroy blood vessels by inflammation. Both arteries and veins are affected. Lymphangitis (inflammation of lymphatic vessels) is sometimes considered a type of vasculitis. Vasculitis is primarily caused ...
(inflammation
Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
of an artery) is rarely associated with aortic dissection. It can also be the result of chest trauma. About 72 to 80% of individuals who present with an aortic dissection have a previous history of hypertension. Illicit drug use with stimulants such as cocaine
Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South Am ...
and methamphetamine
Methamphetamine (contracted from ) is a potent central nervous system (CNS) stimulant that is mainly used as a recreational drug and less commonly as a second-line treatment for attention deficit hyperactivity disorder and obesity. Meth ...
is also a modifiable risk factor for AD. It can also be caused by smoking.
A bicuspid aortic valve (a type of congenital heart disease involving the aortic valve) is found in 7–14% of individuals who have an aortic dissection. These individuals are prone to dissection in the ascending aorta. The risk of dissection in individuals with bicuspid aortic valves is not associated with the degree of 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 the valve.
Connective tissue disorders such as Marfan syndrome
Marfan syndrome (MFS) is a multi-systemic genetic disorder that affects the connective tissue. Those with the condition tend to be tall and thin, with long arms, legs, fingers, and toes. They also typically have exceptionally flexible joints a ...
, Ehlers–Danlos syndrome, and Loeys–Dietz syndrome
Loeys–Dietz syndrome (LDS) is an autosomal dominant genetic connective tissue disorder. It has features similar to Marfan syndrome and Ehlers–Danlos syndrome. The disorder is marked by aneurysms in the aorta, often in children, and the aort ...
increase the risk of aortic dissection. Similarly, vasculitides such as Takayasu's arteritis, giant cell arteritis, polyarteritis nodosa, and Behçet's disease have been associated with a subsequent aortic dissection. Marfan Syndrome is found in 5–9% of individuals who had an aortic dissection. In this subset, the incidence in young individuals is increased. Individuals with Marfan syndrome tend to have aneurysms of the aorta and are more prone to proximal dissections of the aorta.
Turner syndrome
Turner syndrome (TS), also known as 45,X, or 45,X0, is a genetic condition in which a female is partially or completely missing an X chromosome. Signs and symptoms vary among those affected. Often, a short and webbed neck, low-set ears, low h ...
also increases the risk of aortic dissection, by aortic root dilatation.[
Chest trauma leading to aortic dissection can be divided into two groups based on cause: blunt chest trauma (commonly seen in car accidents) and iatrogenic. Iatrogenic causes include trauma during cardiac catheterization or due to an ]intra-aortic balloon pump
The intra-aortic balloon pump (IABP) is a mechanical device that increases myocardial oxygen perfusion and indirectly increases cardiac output through afterload reduction. It consists of a cylindrical polyurethane balloon that sits in the aor ...
.
Aortic dissection may be a late sequela of heart surgery. About 18% of individuals who present with an acute aortic dissection have a history of open-heart surgery. Individuals who have undergone aortic valve replacement for aortic insufficiency are at particularly high risk because aortic regurgitation causes increased blood flow in the ascending aorta. This can cause dilatation and weakening of the walls of the ascending aorta.
Syphilis only potentially causes aortic dissection in its tertiary stage.[
]
Pathophysiology
As with all other arteries, the aorta is made up of three layers, the intima, the media
Media may refer to:
Communication
* Media (communication), tools used to deliver information or data
** Advertising media, various media, content, buying and placement for advertising
** Broadcast media, communications delivered over mass el ...
, and the adventitia. The intima is in direct contact with the blood inside the vessel, and mainly consists of a layer of endothelial cells on a basement membrane
The basement membrane is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling. The basement membrane sits between epithelial tissues including mesothelium and ...
; the media contains connective and muscle tissue, and the vessel is protected on the outside by the adventitia, comprising connective tissue.[
In an aortic dissection, blood penetrates the intima and enters the media layer. The high pressure rips the tissue of the media apart along the laminated plane splitting the inner two-thirds and the outer one-third of the media apart.] This can propagate along the length of the aorta for a variable distance forward or backward. Dissections that propagate towards the iliac bifurcation (with the flow of blood) are called anterograde dissections and those that propagate towards the aortic root (opposite of the flow of blood) are called retrograde dissections. The initial tear is usually within 100 mm of the aortic valve, so a retrograde dissection can easily compromise the pericardium leading to a hemopericardium. Anterograde dissections may propagate all the way to the iliac bifurcation of the aorta, rupture the aortic wall, or recanalize into the intravascular lumen leading to a double-barrel aorta. The double-barrel aorta relieves the pressure of blood flow and reduces the risk of rupture. Rupture leads to hemorrhaging into a body cavity, and prognosis depends on the area of rupture. Retroperitoneal and pericardial ruptures are both possible.
The initiating event in aortic dissection is a tear in the intimal lining of the aorta. Due to the high pressures in the aorta, blood enters the media at the point of the tear. The force of the blood entering the media causes the tear to extend. It may extend proximally (closer to the heart) or distally (away from the heart) or both. The blood travels through the media, creating a false lumen (the true lumen is the normal conduit of blood in the aorta). Separating the false lumen from the true lumen is a layer of intimal tissue known as the intimal flap.
The vast majority of aortic dissections originate with an intimal tear in either the ascending aorta (65%), the aortic arch (10%), or just distal to the ligamentum arteriosum in the descending thoracic aorta (20%).
As blood flows down the false lumen, it may cause secondary tears in the intima. Through these secondary tears, the blood can re-enter the true lumen.
While it is not always clear why an intimal tear may occur, quite often it involves degeneration of the collagen and elastin that make up the media. This is known as cystic medial necrosis and is most commonly associated with Marfan syndrome and is also associated with Ehlers-Danlos syndrome.
In about 13% of aortic dissections, no evidence of an intimal tear is found. In these cases, the inciting event is thought to be an intramural hematoma (caused by bleeding within the media). Since no direct connection exists between the true lumen and the false lumen in these cases, diagnosing an aortic dissection by aortography
Aortography involves placement of a catheter in the aorta and injection of contrast material while taking X-rays of the aorta. The procedure is known as an aortogram. The diagnosis of aortic dissection can be made by visualization of the intima ...
is difficult if the cause is an intramural hematoma. An aortic dissection secondary to an intramural hematoma should be treated the same as one caused by an intimal tear.
Diagnosis
Because of the varying symptoms of aortic dissection, the diagnosis is sometimes difficult to make. Concern should be increased in those with low blood pressure, neurological problems, and an unequal pulses.
While taking a good history from the individual may be strongly suggestive of an aortic dissection, the diagnosis cannot always be made by history and physical signs alone. Often, the diagnosis is made by visualization of the intimal flap on a diagnostic imaging test. Common tests used to diagnose an aortic dissection include a CT scan
A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...
of the chest with iodinated contrast material and a transesophageal echocardiogram. The proximity of the aorta to the esophagus
The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the ...
allows the use of higher-frequency ultrasound for better anatomical images. Other tests that may be used include an aortogram or magnetic resonance angiogram of the aorta. Each of these tests has pros and cons, and they do not have equal sensitivities and specificities in the diagnosis of aortic dissection.
In general, the imaging technique chosen is based on the pretest likelihood of the diagnosis, availability of the testing modality, patient stability, and the sensitivity and specificity of the test.
D-dimer
A measurement of blood D-dimer level may be useful in diagnostic evaluation. A level less than 500 ng/ml may be considered evidence against a diagnosis of aortic dissection,[ although this guideline is only applicable in cases deemed "low risk" and within 24 hours of symptom onset. 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 ...
does not advise using this test in making the diagnosis, as evidence is still tentative.
Chest X-ray
Chest radiograph
A chest radiograph, called a chest X-ray (CXR), or chest film, is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common film taken in me ...
y may although demonstrate a change in the morphology of the thoracic aorta which can be seen in aortic dissection. Classically, new widening of the mediastinum
The mediastinum (from ) is the central compartment of the thoracic cavity. Surrounded by loose connective tissue, it is an undelineated region that contains a group of structures within the thorax, namely the heart and its vessels, the esophagu ...
on radiograph is of moderate sensitivity
Sensitivity may refer to:
Science and technology Natural sciences
* Sensitivity (physiology), the ability of an organism or organ to respond to external stimuli
** Sensory processing sensitivity in humans
* Sensitivity and specificity, statisti ...
for detecting an ascending aortic dissection; however, this finding is of low specificity, as many other conditions can cause apparent widening of the mediastinum.
There are several other associated radiographic findings:
* The "calcium sign" describes an apparent separation of the intimal calcification from the outer aortic margin by greater than 10 mm.
* Pleural effusion
A pleural effusion is accumulation of excessive fluid in the pleural space, the potential space that surrounds each lung.
Under normal conditions, pleural fluid is secreted by the parietal pleural capillaries at a rate of 0.6 millilitre per ...
s, more commonly in descending aortic dissections, and typically left-sided.
* Other: the obliteration of the aortic knob, depression of the left mainstem bronchus, loss of the paratracheal stripe, and tracheal deviation.
Importantly, about 12 to 20% of aortic dissections are not detectable by chest radiograph; therefore, a "normal" chest radiograph does not rule out aortic dissection. If there is high clinical suspicion, a more sensitive imaging test ( CT angiogram, MR angiography, or transesophageal echo) may be warranted.
Computed tomography
Computed tomography angiography is a fast, non-invasive test that gives an accurate three-dimensional view of the aorta. These images are produced by taking rapid, thin-cut slices of the chest and abdomen, and combining them in the computer to create cross-sectional slices. To delineate the aorta to the accuracy necessary to make the proper diagnosis, an iodinated contrast material is injected into a peripheral vein. Contrast is injected and the scan performed using a bolus tracking method. This type of scan is timed to injection to capture the contrast as it enters the aorta. The scan then follows the contrast as it flows through the vessel. It has a sensitivity of 96 to 100% and a specificity of 96 to 100%. Disadvantages include the need for iodinated contrast material and the inability to diagnose the site of the intimal tear.
File:DissectionCT.png, CT with contrast demonstrating aneurysmal dilation and a dissection of the ascending aorta (type A Stanford)
File:Descending (Type B Stanford) Aortic Dissection.PNG, Chest CT with descending (type B Stanford) aortic dissection (red circle)
File:Dissection2018WithPericardial.jpg, Type A dissection with pericardial effusion as a result.
MRI
Magnetic resonance imaging (MRI) is also used for the detection and assessment of aortic dissection, with a sensitivity of 98% and a specificity of 98%. An MRI examination of the aorta produces a three-dimensional reconstruction of the aorta, allowing the physician to determine the location of the intimal tear and the involvement of branch vessels, and to locate any secondary tears. It is a noninvasive test, does not require the use of iodinated contrast material, and can detect and quantitate the degree of aortic insufficiency.
The disadvantage of the MRI scan in the face of aortic dissection is that it may be available only in larger hospitals, and the scan is relatively time-consuming, which could be dangerous in people who are already very unwell. Due to the high-intensity magnetic fields used during MRI, it cannot be used on individuals with metallic implants. In addition, some individuals experience claustrophobia
Claustrophobia is the fear of confined spaces. It can be triggered by many situations or stimuli, including elevators, especially when crowded to capacity, windowless rooms, and hotel rooms with closed doors and sealed windows. Even bedrooms wit ...
while surrounded by the MRI magnet.
Ultrasound
The transesophageal echocardiogram (TEE) is a good test in the diagnosis of aortic dissection, with a sensitivity up to 98% and a specificity up to 97%. It has become the preferred imaging modality for suspected aortic dissection. It is a relatively noninvasive test, requiring the individual to swallow the echocardiography probe. It is especially good in the evaluation of AI in the setting of ascending aortic dissection and to determine whether the ostia (origins) of the coronary arteries are involved. While many institutions give sedation during transesophageal echocardiography for added patient comfort, it can be performed in cooperative individuals without the use of sedation. Disadvantages of TEE include the inability to visualize the distal ascending aorta (the beginning of the aortic arch), and the descending abdominal aorta that lies below the stomach
The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...
. A TEE may be technically difficult to perform in individuals with esophageal strictures or varices.
File:Aortic dissection E00249 (CardioNetworks ECHOpedia).webm, Aortic dissection with an intramural hematoma as seen on TEE
File:UOTW 17 - Ultrasound of the Week 1.webm, Type A aortic dissection
File:UOTW 17 - Ultrasound of the Week 2.webm, Type A aortic dissection[
File:UOTW 55 - Ultrasound of the Week 4.webm, Dissection of both the thoracic and abdominal aorta]
File:UOTW 55 - Ultrasound of the Week 3.webm, Dissection of both the thoracic and abdominal aorta[
]
Aortogram
An aortogram involves the placement of a catheter in the aorta and injection of contrast material while taking X-rays of the aorta. The procedure is known as aortography
Aortography involves placement of a catheter in the aorta and injection of contrast material while taking X-rays of the aorta. The procedure is known as an aortogram. The diagnosis of aortic dissection can be made by visualization of the intima ...
. Previously thought to be the diagnostic gold standard
A gold standard is a Backed currency, monetary system in which the standard economics, economic unit of account is based on a fixed quantity of gold. The gold standard was the basis for the international monetary system from the 1870s to the ...
, it has been supplanted by other, less-invasive imaging modalities.
Classification
Several different classification systems have been used to describe aortic dissections. One such classification is based on chronicity and labels aortic dissections as hyperacute (<24 hours duration), acute (2–7 days), subacute (8–30 days), and chronic (>30 days). The systems commonly in use are based on either the anatomy of the dissection or the duration of onset of symptoms before the presentation. The Stanford system is used more commonly now, as it is more attuned to the management of the patient.
DeBakey
The DeBakey system, named after cardiothoracic surgeon Michael E. DeBakey, is an anatomical description of the aortic dissection. It categorizes the dissection based on where the original intimal tear is located and the extent of the dissection (localized to either the ascending aorta or descending aorta or involving both the ascending and descending aorta).[
* Type I – originates in ascending aorta, and propagates at least to the aortic arch and often beyond it distally. It is most often seen in patients less than 65 years of age and is the most lethal form of the disease.
* Type II – originates in the ascending aorta and is confined to it.
* Type III – originates in the descending aorta and rarely extends proximally, but will extend distally. It most often occurs in elderly patients with ]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 hypertension.
Stanford
The Stanford classification is divided into two groups, A and B, depending on whether the ascending aorta is involved.[
* A – involves the ascending aorta and/or aortic arch, and possibly the descending aorta. The tear can originate in the ascending aorta, the aortic arch, or more rarely, in the descending aorta. It includes DeBakey types I and II.
* B – involves the descending aorta or the arch (distal to the left subclavian artery), without the involvement of the ascending aorta. It includes DeBakey type III.
The Stanford classification is useful as it follows clinical practice, as type A ascending aortic dissections generally require primary surgical treatment, whereas type B dissections generally are treated medically as initial treatment with surgery reserved for any complications.]
The main indication for surgical repair of type A dissections is the prevention of acute hemorrhagic pericardial tamponade due to leakage of blood through the dissected layers of the intrapericardial proximal aorta. A secondary indication is acute aortic valve insufficiency (regurgitation): ascending aortic dissections often involve the aortic valve, which, having lost its suspensory support, telescopes down into the aortic root, resulting in aortic incompetence. The valve must be resuspended to be reseated, as well as to repair or prevent coronary artery injury. Also, the area of dissection is removed and replaced with a Dacron graft to prevent further dissection from occurring. However, type B dissections are not improved, from a mortality point of view, by the operation, unless leaking, rupture, or compromise to other organs, e.g. kidneys, occurs.
Prevention
Among the recognized risk factors for aortic dissection, hypertension, abnormally high levels of lipids (such as cholesterol) in the blood, and smoking tobacco are considered preventable risk factors.[
Repair of an enlargement of the ascending aorta from an aneurysm or previously unrecognized and untreated aortic dissections is recommended when greater than in size to decrease the risk of dissection. Repair may be recommended when greater than in size if the person has one of the several connective-tissue disorders or a family history of a ruptured aorta.
]
Management
In an acute dissection, treatment choice depends on its location. For Stanford type A (ascending aortic) dissection, surgical management is superior to medical management. For uncomplicated Stanford type B (distal aortic) dissections (including abdominal aortic dissections), medical management is preferred over surgery. Complicated Stanford type B aortic dissections require surgical intervention after initiation of medical therapy.
The risk of death due to aortic dissection is highest in the first few hours after the dissection begins, and decreases afterward. Because of this, the therapeutic strategies differ for the treatment of an acute dissection compared to a chronic dissection. An acute dissection is one in which the individual presents within the first two weeks. If the individual has managed to survive this window period, their prognosis is improved. About 66% of all dissections present in the acute phase. Individuals who present two weeks after the onset of the dissection are said to have chronic aortic dissections. These individuals have been self-selected as survivors of the acute episode and can be treated with medical therapy as long as they are stable.
Medication
Aortic dissection generally presents as a hypertensive emergency, and the prime consideration of medical management is to decrease the shear stress
Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. '' Normal stress'', on ...
in the aortic wall (dP/dt (force of ejection of blood from the left ventricle
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper ...
)) by decreasing blood pressure and the heart rate. The target blood pressure should be a mean arterial pressure (MAP) of 60 to 75 mmHg, or the lowest blood pressure tolerated. Initial decreases should be by about 20%.[ The target heart rate is less than 65 beats per minute. Long-term blood pressure control is required for every person who has experienced aortic dissection.
Beta blockers are the first-line treatment for patients with acute and chronic aortic dissection. In acute dissection, fast-acting agents can be given intravenously and have doses that are easier to adjust (such as esmolol, propranolol, or labetalol) is preferred. Vasodilators such as sodium nitroprusside can be considered for people with ongoing high blood pressure, but they should never be used alone, as they often stimulate a reflexive increase in the heart rate.
Calcium channel blockers can be used in the treatment of aortic dissection, particularly if a contraindication to the use of beta-blockers exists. The calcium channel blockers typically used are ]verapamil
Verapamil, sold under various trade names, is a calcium channel blocker medication used for the treatment of high blood pressure, angina (chest pain from not enough blood flow to the heart), and supraventricular tachycardia. It may also be ...
and diltiazem
Diltiazem, sold under the brand name Cardizem among others, is a calcium channel blocker medication used to treat high blood pressure, angina, and certain heart arrhythmias. It may also be used in hyperthyroidism if beta blockers cannot be ...
, because of their combined vasodilator and negative inotropic effects.
If the individual has refractory hypertension (persistent hypertension on the maximum doses of three different classes of antihypertensive agents), involvement of the renal arteries in the aortic dissection plane should be considered.
Surgical
Indications for the surgical treatment of aortic dissection include an acute proximal aortic dissection and an acute distal aortic dissection with one or more complications. Complications include compromise of a vital organ, rupture or impending rupture of the aorta, retrograde dissection into the ascending aorta. These are more common with a history of Marfan syndrome or Ehlers-Danlos syndrome.
The objective in the surgical management of aortic dissection is to resect (remove) the most severely damaged segments of the aorta and to obliterate the entry of blood into the false lumen (both at the initial intimal tear and any secondary tears along the vessel). While excision of the intimal tear may be performed, it does not significantly change mortality.
The particular treatment used depends on the segment or segments of the aorta involved. Some treatments are:
* Open aortic surgery
Open aortic surgery (OAS), also known as open aortic repair (OAR), describes a technique whereby an abdominal, thoracic or retroperitoneal surgical incision is used to visualize and control the aorta for purposes of treatment, usually by the repla ...
with replacement of the damaged section of the aorta with a tube graft (often made of Dacron) when no damage to the aortic valve is seen
* Bentall procedure – replacement of the damaged section of the aorta and replacement of the aortic valve
* David procedure
Valve-sparing aortic root replacement (also known as the David procedure) is a cardiac surgery procedure which is used to treat Aortic aneurysms and to prevent Aortic dissection. It involves replacement of the aortic root without replacement of ...
– replacement of the damaged section of the aorta and reimplantation of the aortic valve
* Thoracic endovascular aortic repair, a minimally invasive surgical procedure usually combined with ongoing medical management
* Replacement of the damaged section of the aorta with a sutureless vascular ring connector
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 t ...
-reinforced Dacron graft: The vascular ring connector is a titanic ring used as a stent in the vascular graft to achieve a quick, blood-sealed, and sutureless anastomosis. Two furrows on the surface of the ring are for fixation of the vascular graft and the aorta. The tapes used to tie against the ring provide a larger contact surface area than the traditional stitches, thus it provides stronger anastomosis and better surgical results.
A number of comorbid conditions increase the surgical risk of repair of an aortic dissection. These conditions include the following:
* Prolonged preoperative evaluation (increased length of time prior to surgery)
* Advanced age
* Comorbid disease states (e.g.: coronary artery disease
Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves Ischemia, the reduction of blood flow to the myocardium, heart muscle due to build-up o ...
)
* Aneurysm leakage
* Cardiac tamponade
* Shock - obstructive shock
* Past history of myocardial infarction
* History of kidney failure (either acute or chronic kidney failure)
Follow-up
The long-term follow-up in individuals who survive aortic dissection involves strict blood pressure control. The relative risk of late rupture of an aortic aneurysm
An aortic aneurysm is an enlargement (dilatation) of the aorta to greater than 1.5 times normal size. They usually cause no symptoms except when ruptured. Occasionally, there may be abdominal, back, or leg pain. The prevalence of abdominal aorti ...
is 10 times higher in individuals who have uncontrolled hypertension, compared to individuals with a systolic pressure below 130 mmHg.
The risk of death is highest in the first two years after the acute event, and individuals should be followed closely during this time period. About 29% of late deaths following surgery are due to rupture of either a dissecting aneurysm or another aneurysm. In addition, a 17% to 25% incidence exists of new aneurysm formation, typically due to dilatation of the residual false lumen. These new aneurysms are more likely to rupture, due to their thinner walls.
Serial imaging of the aorta is suggested, with MRI being the preferred imaging technique.
Prognosis
Of all people with aortic dissection, 40% die immediately and do not reach a hospital in time. Of the remainder, 1% die every hour, making prompt diagnosis and treatment a priority. Even after diagnosis, 5–20% die during surgery or in the immediate postoperative period.[ In ascending aortic dissection, if surgery is decided to be not appropriate, 75% die within 2 weeks. With aggressive treatment, 30-day survival for thoracic dissections may be as high as 90%.][
]
Epidemiology
Establishing the incidence of aortic dissection has been difficult because many cases are only diagnosed after death (which may have been attributed to another cause), and is often initially misdiagnosed. Aortic dissection affects an estimated 2.0–3.5 people per every 100,000 every year. Studies from Sweden suggest that the incidence of aortic dissection may be rising. Men are more commonly affected than women: 65% of all people with aortic dissection are male. The mean age at diagnosis is 63 years.[ In females before the age of 40, half of all aortic dissections occur during ]pregnancy
Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occurs by sexual intercourse, but ...
(typically in the third trimester or early postpartum period). Dissection occurs in about 0.6% of pregnancies.
History
The earliest fully documented case of aortic dissection is attributed to Frank Nicholls in his autopsy
An autopsy (post-mortem examination, obduction, necropsy, or autopsia cadaverum) is a surgical procedure that consists of a thorough examination of a corpse by dissection to determine the cause, mode, and manner of death or to evaluate any dis ...
report of King George II of Great Britain, who had been found dead on 25 October 1760; the report describes a dissection of the aortic arch and into the pericardium.[ The term "aortic dissection" was introduced by the French physician J. P. Maunoir in 1802, and René Laennec labeled the condition "dissecting aneurysm".][ London cardiologist ]Thomas Bevill Peacock
Thomas Bevill Peacock (21 December 1812 – 31 May 1882) was a cardiologist in London remembered for founding the London Chest Hospital. He also made a large contribution to the understanding of aortic dissection by publishing several case series ...
contributed to the understanding of the condition by publishing two series of the cases described in the literature so far: 19 cases in an 1843 review, and 80 in 1863.[ The characteristic symptom of tearing pain in the chest was recognized in 1855 when a case was diagnosed in life.][
Surgery for aortic dissection was first introduced and developed by Michael E. DeBakey, Denton Cooley, and Oscar Creech, cardiac surgeons associated with the ]Baylor College of Medicine
Baylor College of Medicine (BCM) is a medical school and research center in Houston, Texas, within the Texas Medical Center, the world's largest medical center. BCM is composed of four academic components: the School of Medicine, the Graduate Sc ...
, Houston, Texas, in 1954. DeBakey developed aortic dissection himself at age 97 in 2005,[ and underwent surgery in 2006.][ Endovascular treatment of aortic dissection was developed in the 1990s.][
]
Society and culture
Ritter Rules are a compilation of reminders, symptoms, and risk factors designed to prevent the misdiagnosis of thoracic aortic dissection. The rules were named after '' Three's Company'' star John Ritter, who died from a thoracic aortic dissection in 2003 after he was misdiagnosed and accidentally treated for a heart attack by his two doctors. The rules were developed by Dianna Milewicz of the University of Texas Health Science Center at Houston
The University of Texas Health Science Center at Houston (UTHealth) is a public academic health science center in Houston, Texas, United States. It was created in 1972 by The University of Texas System Board of Regents. It is located in the ...
seven years after Ritter's premature death, and were jointly published by the non-profit organization in Ritter's honor and the Thoracic Aortic Disease Coalition.
Lucille Ball
Lucille Désirée Ball (August 6, 1911 – April 26, 1989) was an American actress, comedienne and producer. She was nominated for 13 Primetime Emmy Awards, winning five times, and was the recipient of several other accolades, such as the Gold ...
was diagnosed with dissecting aortic aneurysm and underwent surgery to repair her aorta and a successful seven-hour aortic valve replacement, but died days later. A greater incidence of aortic aneurysm is seen in cigarette smokers; Ball had been a heavy smoker most of her life.
Playwright Jonathan Larson, best known for the musical '' Rent'', died in 1996 of an aortic dissection believed to be due to undiagnosed Marfan Syndrome
Marfan syndrome (MFS) is a multi-systemic genetic disorder that affects the connective tissue. Those with the condition tend to be tall and thin, with long arms, legs, fingers, and toes. They also typically have exceptionally flexible joints a ...
.
''Days of Our Lives
''Days of Our Lives'' (also stylized as ''Days of our Lives''; simply referred to as ''Days'' or ''DOOL'') is an American television soap opera that streams on the streaming service Peacock (streaming service), Peacock. The soap, which aired on ...
'' and ''Babylon 5
''Babylon 5'' is an American space opera television series created by writer and producer J. Michael Straczynski, under the Babylonian Productions label, in association with Straczynski's Synthetic Worlds Ltd. and Warner Bros. Domestic Televi ...
'' actor Richard Biggs died on May 22, 2004 at the age of 44 due to complications from aortic dissection.
Lux Interior of The Cramps died at the Glendale Memorial Hospital on February 4, 2009, at the age of 62, following an aortic dissection which, contrary to initial reports about a pre-existing condition, was "sudden, shocking and unexpected".
Alan Thicke died in 2016 of type-A aortic dissection at the Providence Saint Joseph Medical Center in Burbank, at the age of 69.
Japanese actress Hiromi Tsuru died in her car from aortic dissection in 2017 at the age of 57.
Taiwanese entertainer Alien Huang died in 2020 at the age of 36.
Kentaro Miura
was a Japanese manga artist. He was best known for his acclaimed dark fantasy series ''Berserk'', which began serialization in 1989 and continued until his death. As of 2021, ''Berserk'' had more than 50 million copies in circulation, making it ...
, writer and artist of the manga ''Berserk
Berserk (meaning "very angry" or "out of control") may refer to:
* ''Berserk'' (manga), a 1989 Japanese manga by Kentaro Miura
** ''Berserk'' (1997 TV series), the first anime adaption of the manga
** ''Berserk'' (2016 TV series), a second adap ...
'', died from aortic dissection in 2021 at the age of 54.
In August 2021, New Zealand cricket
Cricket is a bat-and-ball game played between two teams of eleven players on a field at the centre of which is a pitch with a wicket at each end, each comprising two bails balanced on three stumps. The batting side scores runs by st ...
er Chris Cairns was put on full life support following an aortic dissection in his home in Canberra, Australia. He was transferred to Sydney, and became paralysed from the waist down due to sustaining a stroke during surgery.
41-year-old guitarist Richie Faulkner of the heavy metal band Judas Priest
Judas Priest are an English heavy metal band formed in Birmingham in 1969. They have sold over 50 million albums and are frequently ranked as one of the greatest metal bands of all time. Despite an innovative and pioneering body of work in th ...
had an aortic aneurysm on September 27, 2021, in the middle of the final song of their 50-minute set at a music festival. He underwent hours of open heart surgery to repair the aortic dissection.
In May 2022, keyboardist Andy Fletcher, a founding member of the UK band Depeche Mode
Depeche Mode are an English electronic music band formed in Basildon, Essex, in 1980. The band currently consists of Dave Gahan (lead vocals and co-songwriting) and Martin Gore (keyboards, guitar, co-lead vocals and main songwriting).
Depech ...
, died unexpectedly at home from an aortic dissection, at the age of 60.
See also
* Carotid artery dissection
* Vertebral artery dissection
References
External links
{{DEFAULTSORT:Aortic Dissection
+
Causes of death
Medical emergencies
Vascular surgery
IgG4-related disease
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