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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 o ...
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, 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; 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 and Ehlers–Danlos syndrome; a
bicuspid aortic valve Bicuspid aortic valve (aka BAV) is a form of heart disease in which two of the leaflets of the aortic valve fuse during development in the womb resulting in a two-leaflet (bicuspid) valve instead of the normal three-leaflet (tricuspid) valve. BA ...
; and previous heart surgery. Major trauma, smoking,
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 Ameri ...
use,
pregnancy Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...
, a
thoracic aortic aneurysm A thoracic aortic aneurysm is an aortic aneurysm that presents primarily in the thorax. A thoracic aortic aneurysm is the "ballooning" of the upper aspect of the aorta, above the diaphragm. Untreated or unrecognized they can be fatal due to dissec ...
, 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, 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 ...
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 Pleurisy, also known as pleuritis, is inflammation of the membranes that surround the lungs and line the chest cavity (pleurae). This can result in a sharp chest pain while breathing. Occasionally the pain may be a constant dull ache. Other sym ...
in nature, it may suggest acute pericarditis caused by bleeding into the sac surrounding the heart. This is a particularly dangerous eventuality, suggesting that acute pericardial tamponade 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 ma ...
, AD is usually not associated with the other suggestive signs, such as heart failure 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 Syncope, commonly known as fainting, or passing out, is a loss of consciousness and muscle strength characterized by a fast onset, short duration, and spontaneous recovery. It is caused by a decrease in blood flow to the brain, typically from ...
(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, 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 poss ...
. 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, 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 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. 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 di ...
. 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 The brachiocephalic artery (or brachiocephalic trunk or innominate artery) is an artery of the mediastinum that supplies blood to the right arm and the head and neck. It is the first branch of the aortic arch. Soon after it emerges, the brachioce ...
(supplying the right arm) or the left subclavian artery (supplying the left arm).


Aortic insufficiency

Aortic insufficiency Aortic regurgitation (AR), also known as aortic insufficiency (AI), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. As a conseq ...
(AI) occurs in half to two-thirds of ascending AD, and the diastolic
heart murmur Heart murmurs are unique heart sounds produced when blood flows across a heart valve or blood vessel. This occurs when turbulent blood flow creates a sound loud enough to hear with a stethoscope. Turbulent blood flow is not smooth. The sound di ...
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 The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. Th ...
, 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 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 ma ...
occurs in 1–2% of aortic dissections. Infarction is caused by the involvement of the
coronary arteries The coronary arteries are the arterial blood vessels of coronary circulation, which transport oxygenated blood to the heart muscle. The heart requires a continuous supply of oxygen to function and survive, much like any other tissue or organ o ...
, 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 (massive ...
therapy, the mortality increases to over 70%, mostly due to bleeding into the pericardial sac, causing
cardiac 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 obstructi ...
.


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 k ...
(fluid collection in the space between the lungs and the chest wall or diaphragm) 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 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, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...
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 Ameri ...
and methamphetamine is also a modifiable risk factor for AD. It can also be caused by smoking. A
bicuspid aortic valve Bicuspid aortic valve (aka BAV) is a form of heart disease in which two of the leaflets of the aortic valve fuse during development in the womb resulting in a two-leaflet (bicuspid) valve instead of the normal three-leaflet (tricuspid) valve. BA ...
(a type of
congenital heart disease A congenital heart defect (CHD), also known as a congenital heart anomaly and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular ...
involving the
aortic valve The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. Th ...
) 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 of the valve.
Connective tissue disorder 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 such as Marfan syndrome, Ehlers–Danlos syndrome, and Loeys–Dietz syndrome increase the risk of aortic dissection. Similarly, vasculitides such as
Takayasu's arteritis Takayasu's arteritis (TA), also known as aortic arch syndrome, nonspecific aortoarteritis, and pulseless disease, is a form of large vessel granulomatous vasculitisAmerican College of Physicians (ACP). Medical Knowledge Self-Assessment Program (MK ...
,
giant cell arteritis Giant cell arteritis (GCA), also called temporal arteritis, is an inflammatory autoimmune disease of large blood vessels. Symptoms may include headache, pain over the temples, flu-like symptoms, double vision, and difficulty opening the mouth. ...
, polyarteritis nodosa, and
Behçet's disease Behçet's disease (BD) is a type of inflammatory disorder which affects multiple parts of the body. The most common symptoms include painful sores on the mucous membranes of the mouth and other parts of the body, inflammation of parts of the ey ...
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 hair ...
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 Iatrogenesis is the causation of a disease, a harmful complication, or other ill effect by any medical activity, including diagnosis, intervention, error, or negligence. "Iatrogenic", ''Merriam-Webster.com'', Merriam-Webster, Inc., accessed 27 ...
. Iatrogenic causes include trauma during cardiac catheterization or due to an intra-aortic balloon pump. 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 Aortic regurgitation (AR), also known as aortic insufficiency (AI), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. As a conseq ...
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 e ...
, and the
adventitia The adventitia () is the outer layer of fibrous connective tissue surrounding an organ. The outer layer of connective tissue that surrounds an artery, or vein – the tunica externa, is also called the ''tunica adventitia''. To some degree, its ...
. The intima is in direct contact with the blood inside the vessel, and mainly consists of a layer of
endothelial cells The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel ...
on a basement membrane; 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 The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. Th ...
, 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 The aortic arch, arch of the aorta, or transverse aortic arch () is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea. Structure The aorta begins ...
(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 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 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 ...
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 does not advise using this test in making the diagnosis, as evidence is still tentative.


Chest X-ray

Chest radiography 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 on radiograph is of moderate sensitivity 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 k ...
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 Computed tomography angiography (also called CT angiography or CTA) is a computed tomography technique used for angiography—the visualization of arteries and veins—throughout the human body. Using contrast injected into the blood vessels, ...
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 The aortic arch, arch of the aorta, or transverse aortic arch () is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea. Structure The aorta begins ...
), 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. Previously thought to be the diagnostic
gold standard A gold standard is a monetary system in which the standard 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 early 1920s, and from the l ...
, 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 no s ...
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 the ...
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 uppe ...
)) by decreasing blood pressure and the heart rate. The target blood pressure should be a
mean arterial pressure In medicine, the mean arterial pressure (MAP) is an average blood pressure in an individual during a single cardiac cycle. MAP is altered by cardiac output and systemic vascular resistance. Testing Mean arterial pressure can be measured dire ...
(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 Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage abnormal heart rhythms, and to protect the heart from a second heart attack after a first heart attack ( secondary prevention). They are ...
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 Propranolol, sold under the brand name Inderal among others, is a medication of the beta blocker class. It is used to treat high blood pressure, a number of types of irregular heart rate, thyrotoxicosis, capillary hemangiomas, performance an ...
, or
labetalol Labetalol is a medication used to treat high blood pressure and in long term management of angina. This includes essential hypertension, hypertensive emergencies, and hypertension of pregnancy. In essential hypertension it is generally less pref ...
) is preferred. Vasodilators such as
sodium nitroprusside Sodium nitroprusside (SNP), sold under the brand name Nitropress among others, is a medication used to lower blood pressure. This may be done if the blood pressure is very high and resulting in symptoms, in certain types of heart failure, and d ...
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, 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 with replacement of the damaged section of the aorta with a tube graft (often made of
Dacron Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foo ...
) when no damage to the
aortic valve The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. Th ...
is seen * Bentall procedure – replacement of the damaged section of the aorta and replacement of the aortic valve * David procedure – 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-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) * Aneurysm leakage *
Cardiac 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 obstructi ...
*
Shock Shock may refer to: Common uses Collective noun *Shock, a historic commercial term for a group of 60, see English numerals#Special names * Stook, or shock of grain, stacked sheaves Healthcare * Shock (circulatory), circulatory medical emergen ...
- obstructive shock * Past history of myocardial infarction * History of
kidney failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...
(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 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 (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...
(typically in the third trimester or early
postpartum The postpartum (or postnatal) period begins after childbirth and is typically considered to end within 6 weeks as the mother's body, including hormone levels and uterus size, returns to a non-pregnant state. The terms puerperium, puerperal pe ...
period). Dissection occurs in about 0.6% of pregnancies.


History

The earliest fully documented case of aortic dissection is attributed to
Frank Nicholls Frank Nicholls (1699 – 7 January 1778) was a physician. He was elected a Fellow of the Royal Society in 1728. He was made reader of anatomy at Oxford University when young and moved to London in the 1730s. Life The second son of John Nicholl ...
in his autopsy 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 René-Théophile-Hyacinthe Laennec (; 17 February 1781 – 13 August 1826) was a French physician and musician. His skill at carving his own wooden flutes led him to invent the stethoscope in 1816, while working at the Hôpital Necker ...
labeled the condition "dissecting aneurysm". London cardiologist Thomas Bevill Peacock 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 S ...
, 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 ''Three's Company'' is an American sitcom television series that aired for eight seasons on ABC from March 15, 1977, to September 18, 1984. It is based on the British sitcom '' Man About the House''. The story revolves around three single room ...
'' star
John Ritter Johnathan Southworth Ritter (September 17, 1948 – September 11, 2003) was an American actor. Ritter was a son of the singing cowboy star Tex Ritter and the father of actors Jason and Tyler Ritter. He is known for playing Jack Tripper on the ...
, 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 T ...
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 Golde ...
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 Jonathan David Larson (February 4, 1960 – January 25, 1996) was an American composer, lyricist and playwright most famous for writing the musicals ''Rent'' and '' Tick, Tick... Boom!'', which explored the social issues of multiculturalism, ...
, best known for the musical '' Rent'', died in 1996 of an aortic dissection believed to be due to undiagnosed Marfan Syndrome. '' Days of Our Lives'' 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 Tele ...
'' actor
Richard Biggs Richard James Biggs II (March 18, 1960 – May 22, 2004) was an American television and stage actor, known for his roles on the television series ''Days of Our Lives'' and ''Babylon 5''. Early life Born in Columbus, Ohio, Biggs attended the Un ...
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 Alan Thicke (born Alan Willis Jeffrey; March 1, 1947December 13, 2016) was a Canadian actor, songwriter, and game and talk show host. He is the father of singer Robin Thicke. In 2013, Thicke was inducted into Canada's Walk of Fame. Thicke was be ...
died in 2016 of type-A aortic dissection at the
Providence Saint Joseph Medical Center Providence Saint Joseph Medical Center is a Catholic hospital in Burbank, California. The hospital has 446 beds, and is part of Providence Health & Services. Its address is 501 South Buena Vista Street, Burbank, California 91505. On the oppo ...
in Burbank, at the age of 69. Japanese actress
Hiromi Tsuru was a Japanese actress, voice actress and narrator. During her life, she was attached to the Himawari Theatre Group as a child and then to Aoni Production at the time of her death. She was most known for voicing the character of Bulma (''Dragon B ...
died in her car from aortic dissection in 2017 at the age of 57. Taiwanese entertainer
Alien Huang Alien Huang (; 28 November 1983 – 15 September 2020), also known as Xiao Gui (Little Ghost), was a Taiwanese singer, actor, television presenter, illustrator and fashion designer. He was a member of Japanese TV Asahi's disbanded boy band ...
died in 2020 at the age of 36. Kentaro Miura, writer and artist of the manga '' Berserk'', 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 str ...
er
Chris Cairns Christopher Lance Cairns (born 13 June 1970) is a former New Zealand cricketer and former ODI captain, who played for the New Zealand cricket team as an all-rounder. Cairns finished his Test career with a batting average of 33.53 and a bowling ...
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 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 Andrew Fletcher may refer to: Government * Andrew Fletcher, Lord Innerpeffer (died 1650), Scottish judge * Andrew Fletcher (patriot) (1655–1716), Scottish writer, politician and patriot * Andrew Fletcher, British Member of Parliament for Haddin ...
, a founding member of the UK band Depeche Mode, died unexpectedly at home from an aortic dissection, at the age of 60.


See also

*
Carotid artery dissection Carotid artery dissection is a separation of the layers of the artery wall supplying oxygen-bearing blood to the head and brain and is the most common cause of stroke in young adults. (Dissection is a blister-like de-lamination between the oute ...
*
Vertebral artery dissection Vertebral artery dissection (VAD) is a flap-like tear of the inner lining of the vertebral artery, which is located in the neck and supplies blood to the brain. After the tear, blood enters the arterial wall and forms a blood clot, thickening t ...


References


External links

{{DEFAULTSORT:Aortic Dissection + Causes of death Medical emergencies Vascular surgery IgG4-related disease Wikipedia medicine articles ready to translate Wikipedia emergency medicine articles ready to translate