Aortic Dissection is a serious cardiovascular condition in which the walls of the aorta begin to separate from each other. It causes a tear through the aortic layers, leading to life-threatening complications.

What is Aortic Dissection?

This is an uncommon but clinically significant pathology of the aorta in which the layers of the aorta separate. It occurs in 30 out of 1 million Americans every year and poses a considerable health risk because of its high mortality rate.¹
In order to understand this tearing of the aortic layers, it is important to understand the anatomy of the aorta. The aorta is the largest artery in your body and carries blood from the heart to the rest of the organs. It has the following parts and layers, which are implicated in aortic dissection:

Parts of the Aorta	Layers of the Aorta
The ascending aorta is the part of the aorta that rises upward from the heart and towards the arch of the aorta.	The tunica externa or adventitia is the outermost layer of the aorta, which carries blood vessels and nerves.
The arch of the aorta is the curved vasculature that connects the ascending and descending aorta.	The tunica media is the central layer of the aorta. It changes the vessel diameter to accommodate changes in blood pressure and provides mechanical support. It also consists of numerous layers that lend it strength.
The descending aorta continues downwards from the arch of the aorta.	The tunica intima is the internal lining of the aorta, which provides a smoother surface for blood flow.

How Does an Aortic Dissection Develop?

It refers to a split in the aorta. It usually starts in the tunica intima, a site that has undergone weakening due to various factors, such as stress and cardiovascular disease.
When the innermost layer has been torn, the high-pressure blood gushing through the aortic lumen enters the wall of the aorta and starts accumulating there. This accumulation causes heavy stress on the tunica media and causes its layers to separate, too.
In addition, this series of changes in the aortic wall structure leads to the formation of a “false lumen,” which compresses the actual lumen of the aorta. It greatly reduces and sometimes completely cuts off the blood supply to various organs in your body.²

Types of Aortic Dissection

Aortic dissections have been classified anatomically based on which part of the aorta the tear occurs in. These classifications are important in estimating prognosis and determining the course of treatment.

The Stanford Classification

The Stanford classification is based on where the dissection occurs in relation to the ascending aorta.

Type of Aortic Dissection	Description
Type A	When the aortic dissection involves the ascending aorta, it is classified as Type A. Since the ascending aorta is close to vital organs, it has a higher mortality rate and requires immediate surgical management.
Type B	When the aortic dissection starts further down in the descending aorta instead of involving the ascending aorta, it is classified as Type B. It is less life-threatening and usually does not require emergency surgery.

The DeBakey Classification

The DeBakey classification is another classification that differentiates between aortic dissection, which requires surgery, and aortic dissection, which does not require immediate surgery for its management.³

Type of Aortic Dissection	Description
Type I 60% of cases	Only the ascending and descending aorta are involved. It requires emergency surgery and is the most lethal type of aortic dissection.
Type II 10-15% of cases	There is only the involvement of the ascending aorta. It may or may not require emergency surgery.
Type III 25-30% of cases	Only the descending aorta is involved, and it does not require emergency surgery.

Stanford’s Classification & DeBakey’s Classification of Aortic Dissection

Causes of Aortic Dissection

This is a result of various factors that result in increased biomechanical stress on the aorta and weaken its walls. These causes and risk factors include:

High Blood Pressure

High blood pressure is known as the most common cause of this condition, as over 70% of people who present with aortic dissection also have hypertension (high blood pressure). The risk for aortic dissection especially increases if your systolic blood pressure is over 132 mm Hg and diastolic blood pressure is over 75 mm Hg. Similarly, having a normal blood pressure is associated with a much lower risk of this condition. ⁴

Congenital Abnormalities

A number of genetic conditions are associated with connective tissue and cardiovascular defects. They cause a weakening of the walls of various blood vessels, including the aorta. These disorders include:

Marfan syndrome
Loeys-Dietz syndrome
Ehlers-Danlos syndrome, vascular type in particular
Turner syndrome
Familial thoracic aortic aneurysm and dissection syndrome

Heart Disease

Coronary artery disease has long been implicated in this condition. Conditions such as arteriosclerosis (narrowing of the blood vessels) and atherosclerosis (hardening of the blood vessels) cause great stress on the aorta and can result in sudden or chronic development of tears in its walls.

Family History

Around 20% of people who experience an aortic dissection or aortic aneurysm (especially in the thoracic aorta) are genetically predisposed to it.⁵

Trauma

Sudden trauma because of blast or penetrating injuries during accidents, falls, and fighting can also result in this condition. However, traumatic aortic injuries like these are usually rare, as they constitute around 1-2% of the complaints patients present to trauma centers with.

Signs & Symptoms of Aortic Dissection

A typical patient with aortic dissection is a middle-aged or older male who may have a history of unmanaged hypertension or heart disease. They could also have a diagnosed genetic condition that affects their connective tissue. They are likely to present with the following signs and symptoms:

Pain

Pain is the most common and significant clinical hallmark of aortic dissection. The pain begins suddenly and is so severe that patients often call it the worst pain they have ever experienced. Pain often starts in the chest and radiates to:

Back
Arms
Neck
Jaw
Between shoulders
Scapula

The location of pain can help doctors determine what type of aortic dissection you have, especially if imaging modalities are not available at hand.

Cardiovascular Signs & Symptoms

The main signs and symptoms are cardiovascular and include:

Abnormally high or low blood pressure
Abnormal heart rate
Weak or absent pulses in the limbs
Murmurs
Shortness of breath
Fainting
Shock

Non-cardiovascular Signs & Symptoms

In addition to cardiovascular signs and symptoms, there are several other features that can be seen in this condition:

Neurological deficits are seen in around 20% of cases
o Confusion
o Weakness
o Numbness
o Difficulty talking
Hoarseness of voice due to compression of the recurrent laryngeal nerve
Difficulty swallowing because of compression of the esophagus
Nausea and vomiting
Excessive sweating⁶

Diagnosis of Aortic Dissection

This is a serious medical emergency that requires a quick clinical exam as well as imaging studies and laboratory investigation.

History & Physical Exam:

Your doctor will ask you if you are experiencing any pain. They will also ask you to describe and localize it. This condition is associated with a distinct type of continuous, burning pain, which is unlike any other condition. In addition, your doctor will run a quick physical exam to check for:

Any differences in blood pressure between your arms
Any drastic differences between your systolic and diastolic blood pressure
Irregular heartbeat
Irregular heart sounds or murmurs
Any signs of shock
Any inequalities or weaknesses in various pulses across your body

Laboratory Investigations:

A variety of baseline investigations are ordered while managing and diagnosing aortic dissection. They help rule out other causes of the signs and symptoms associated with the condition, as well as help your doctor establish the severity of the dissection:

Full blood count — to check your body for infection and anemia
Troponin levels — to rule out myocardial infarction
Coagulation profile — to assess for clotting or bleeding disorders
Renal function tests — to rule out renal damage
Liver function tests — to rule out hepatic and mesenteric ischemia
Serum electrolytes — to rule out fluid shifts and electrolyte imbalance

Imaging:

It is vital to perform emergency radiological investigations to confirm the diagnosis of this condition, even if your doctor has not yet received the results of lab Investigations. These modalities include:

Chest X-Ray

A simple chest X-ray can show a widened chest cavity or mediastinum, which occurs in at least 80% of the cases of aortic dissection. Abnormalities in the aortic arch may also be seen as a “knob” on the aorta.

CT Angiography

A computerized topographic angiography with contrast is considered the gold standard for diagnosing aortic dissection, as both its specificity and sensitivity are around 100%. The use of a contrast dye helps doctors visualize the actual extent of aortic dissection — the shape and size of the tear, where it is located, and the severity of the false lumen that has formed.

MRI

MRI scans are used to detect aortic dissection in patients who are allergic to contrast used in CT scans or have kidney disease. They give a detailed picture of the vasculature and structure of the aorta, as well as abnormalities of blood flow in the aortic lumen.

Transesophageal Echocardiography

Transesophageal echocardiography is used to diagnose this condition in unstable patients in an acute clinical setting. It can showcase where the flap from the tear is present, the presence of true and false lumens, and the extent of the dissection.⁷

Anatomical features of type B Aortic dissections in illustration and CTA imaging (a and b) TL: True Lumen FL: False Lumen. Image courtesy: Simulation of thoracic endovascular aortic repair in a perfused patient-specific model of type B aortic dissection, Researchgate 2024. Available at: Researchgate

How is Aortic Dissection Treated?

The treatment involves medication, surgery as well as lifestyle modification to prevent recurrence.

Immediate Management

If you have presented to the ER with aortic dissection, the priority for medical professionals will be to stabilize you. They will establish IV access to administer fluids and medication to you as soon as possible. In addition, they will start monitoring certain vital signs, including your blood pressure, heart rate, and oxygen saturation.

Pharmacologic Treatment

A variety of medications are used for the short-term and long-term treatment of this condition, such as:

Analgesics

Aortic dissection is associated with excruciating pain. Therefore, healthcare professionals immediately administer medications — mostly opioids — for rapid pain relief, such as:

Morphine
Fentanyl
Hydromorphone
Meperidine

Antihypertensives

The prognosis of aortic dissection can be rapidly improved by normalizing your blood pressure and reducing the stress on your aorta. Examples of blood pressure-lowering drugs include:

Beta-blockers
o Labetalol
o Esmolol
o Metoprolol
o Propranolol
Calcium channel blockers
o Diltiazem
o Verapamil
o Nicardipine
Vasodilators
o Sodium nitroprusside
o Hydralazine

Surgical Treatment

Surgical treatment is lifesaving in patients with severe or complicated aortic dissection. Surgery often includes repair of the affected part of the aorta or its replacement with a graft.

Aortic dissection treated using AVPs and coils — Aortic dissection was treated using AVPs and coils. Image courtesy: Case Report: The application of amplatzer vascular plug to repair aortic dissection intimal tears and false lumen, Researchgate, 2024, available at Researchgate

Lifestyle Modifications

It is necessary to adopt a number of lifestyle modifications to prevent the recurrence of this condition. These include:

Strictly managing your medical conditions, such as hypertension and hyperlipidemia
Maintaining normal body weight
Adopting a low-sodium diet
Healthy eating
Avoiding highly stressful environments
Practicing stress reduction

Complications of Aortic Dissection

The aorta is the most important artery in the body, so aortic dissection can have devastating complications if it is not managed promptly. 30% of patients die before reaching the ER, and 20-30% die even after medical help. Complications include:

Myocardial infarction
Aortic rupture
Pericardial tamponade
Superior vena cava syndrome
Horner’s syndrome ⁸

Aortic Dissection Vs. Aneurysm

Aortic dissection and aortic aneurysm are both serious disorders of the aorta. The term “aortic dissection” refers to the tearing of the aortic wall, whereas “aortic aneurysm” refers to an abnormal dilation in the aorta, which causes it to balloon.

Aortic Dissection	Aortic Aneurysm
Tear in the wall of the aorta	Abnormal enlargement of a part of the aorta
A sudden and severe onset	Gradual onset
Severe, tearing pain	Often unsymptomatic until rupture
Lower mortality	Higher mortality if ruptured

Conclusion

Aortic dissection is an acute vascular disorder of the aorta, the largest artery in the human body. It causes a tear in the wall of the aorta, often starting at the innermost later. It has high mortality and needs to be managed as an emergency.

Refrences

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Sayed, A., Munir, M., & Bahbah, E. I. (2021). Aortic Dissection: A Review of the Pathophysiology, Management and Prospective Advances. Current Cardiology Reviews, 17(4). https://doi.org/10.2174/1573403×16666201014142930
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Aortic Dissection – Cardiovascular Disorders. (n.d.). MSD Manual Professional Edition. https://www.msdmanuals.com/professional/cardiovascular-disorders/diseases-of-the-aorta-and-its-branches/aortic-dissection
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Makoto Hibino, Yoichiro Otaki, Kobeissi, E., Pan, H., Hiromi Hibino, Henock Taddese, Majeed, A., Verma, S., Tsuneo Konta, Yamagata, K., Fujimoto, S., Kazuhiko Tsuruya, Narita, I., Kasahara, M., Yugo Shibagaki, Kunitoshi Iseki, Moriyama, T., Kondo, M., Koichi Asahi, & Watanabe, T. (2022). Blood Pressure, Hypertension, and the Risk of Aortic Dissection Incidence and Mortality: Results From the J-SCH Study, the UK Biobank Study, and a Meta-Analysis of Cohort Studies. Circulation, 145(9), 633–644. https://doi.org/10.1161/circulationaha.121.056546
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Mancini, M. C. (2023, June 30). Aortic Dissection Clinical Presentation: History, Physical Examination, Complications. Medscape.com; Medscape. https://emedicine.medscape.com/article/2062452-clinical
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Aortic Dissection: Early Signs, Risks & When to Seek Help

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