VIDEOS EXPLAINING AORTIC DISEASE
Aortic Dissections are Like Snowflakes
It is common for aortic dissections to occur suddenly, violently, and catastrophically.
Aortic dissections involve a tear of the innermost layer (lining) of the Aortic wall (called the intima). Once this tear occurs, flowing blood creates a channel that twists and winds behind the intima within the middle layer (media) of the Aortic wall - much like a meandering stream finding its way through uneven terrain.
As the new blood channel separates the layers of the Aortic wall, the integrity of the Aortic wall weakens. This means that with each pulsation, the chances of the Aorta completely giving way and rupturing are increased. If the Aorta ruptures, the hemorrhage has a likelihood of causing death. This is a true emergency.
Aortic dissections are like snowflakes because each dissection is unique, and no two dissection patients are the same.
The location and size of the tear, the channel within the aortic wall, and the extent of the tear are all unpredictable. As a result, each patient with an Aortic dissection must be evaluated and treated in a customized fashion.
A nomenclature differentiates the two channels with blood flowing in two separate channels (called a double barrel). The “true lumen” is the channel that corresponds to the space where blood was flowing in the normal aorta before the tear. The “false lumen” designates that space within the Aortic wall where blood circulates in a new channel. The false lumen also contributes to the overall weakness of the aortic wall.
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Aortic dissections are typically classified according to the Stanford Classification system, which separates patients into two groups based on the location of the initiating (entry) tear. If the entry tear begins in the ascending Aorta, we call this a Type A aortic dissection. A Type B Aortic dissection implies that the entry tear of the dissection begins in the descending thoracic aorta beyond the origin of the left subclavian artery (blood vessel supplying the left arm).
Type A aortic dissections require immediate, emergent open heart surgery, while Type B Aortic dissections are frequently managed with medical therapy. This paradigm is changing due to the advent of endovascular aortic stent grafts.
Finally, other consequences can occur from the tear. Patients usually develop intense back pain between the shoulder blades. Additionally, the flap of intimal tissue (called the septum) can occlude flow to a branch vessel of the Aorta. If this occurs, the organ(s) that the vessel supplies could lack adequate blood flow. This is called “malperfusion” and is an emergency. The longer the malperfusion persists, the greater the risk for death.
Battle of the Bulge: Understanding Aortic Aneurysms
Getting started
The Battle of the Bulge was a carefully orchestrated, surprise military offensive by the Germans in WWII to recapture the valuable harbor of Antwerp. This offensive caught Allied soldiers off-guard. The “bulge” in the Battle of the Bulge refers to the inward bulge of the Allied Forces' lines of defense in response to the attack. As we know, bulges can occur in many forms, and when associated with aortic aneurysms, bulges can be deadly.
Anatomy and definitions
Abdominal aortic aneurysm (AAA)
Aortic aneurysms are a localized enlargement of a region of the aorta, sometimes referred to as a “bulge” or “bubble.” As you recall, the aorta is divided into several distinct anatomic sections. The diameter, or width, of the normal aorta in each of these regions varies. The aortic segments are the aortic root, ascending aorta, aortic arch, descending thoracic aorta, and abdominal aorta.
The overall diameter of the aorta is determined by many factors, including how tall you are, how much you weigh, and your family history. For example, the ascending aorta is usually the largest in diameter. There is progressive tapering of the aortic diameter continuously to the aortic bifurcation in the abdomen.
An aortic aneurysm is technically defined as a section of the aorta which measures twice the normal width (2 * normal aortic diameter). However, this measurement is relative from patient to patient because of the variability of everyone’s baseline aortic diameter and the variability with the aorta itself.
Nevertheless, any section of the aorta greater than an absolute diameter of 3.5cm is of concern. This doesn’t necessarily mean that an aorta of 3.5cm always needs immediate treatment. Still, it is an abnormal segment that can potentially lead to a situation that needs to be treated.
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Another term that denotes enlargement of the aorta is ectasia. An ectatic aorta is generally enlarged (non-localized) and may be a marker of an aortopathy (disease of the aortic wall). This is generally a whole different disease process.
Aortic aneurysms
An abdominal aortic aneurysm (AAA) is a localized expansion of the aorta in the stomach region. Many call the region below the ribs and above the waist the “stomach,” but in medical terms, it is the abdomen (lower half of the torso). The stomach is technically a digestive organ within the abdomen, not a body section. There are many important organs and structures within the abdomen.
A thoracic aortic aneurysm (TAA) is a localized expansion of the aorta that develops in the chest cavity (internal to the ribs and breastbone). The diaphragm is used for breathing that divides the chest cavity from the abdominal cavity (roughly in the middle of the torso). The aorta passes through a specially designed hole in the diaphragm, which also accommodates the esophagus and aorta together.
There are many risk factors for developing an aortic aneurysm. These include high blood pressure, heart disease, family history, and a connective tissue disorder diagnosis.
You may want to check out my book, "Risk Factors for Developing Aortic Disease,” to learn more.
When an aneurysm develops, the integrity of the aortic wall (blood vessel) weakens, and there is a risk that the aorta could rupture at the point of maximal weakness and result in massive internal bleeding. Aneurysms are a result of a degenerative process.
Symptoms associated with aortic aneurysms
Frequently, an aortic aneurysm does not cause any symptoms. It is usually found incidentally when an X-ray, CAT scan, or ultrasound is performed for another medical reason. Most patients are surprised to learn they have an aortic aneurysm. When an aneurysm does develop symptoms, it can be associated with stomach pain, lower back pain, upper back pain, or pain in the chest. The pain is usually described as sharp and stabbing when in the chest and dull when in the abdomen.
Diagnosing an aortic aneurysm
Additional studies are usually needed when an aortic aneurysm is detected, whether in the chest or abdomen. The entire aorta needs to be evaluated from the aortic valve to the aortic bifurcation to ensure that no other section of the aorta is affected by an aneurysm. This usually involves a CAT scan of both the chest and abdomen. This test can also be used to develop possible treatment options by physicians.
If the aneurysm is close to the heart (aortic root or ascending aorta), an echocardiogram (a cardiac ultrasound) is needed to inspect the aortic valve. The aortic aneurysm could distort the function of the aortic valve.
Treatments for aortic aneurysms
The decision on when to treat an aortic aneurysm is individualized based on patient-specific factors and the size of the aneurysm itself. Some small aneurysms can be monitored. Those that are larger may require surgery. Options include open surgical repair or endovascular aortic stents. At a minimum, patients with aortic aneurysms need their blood pressure well-controlled, often with medications, to decrease the stress and strain on the aortic wall associated with blood pressure. The higher the blood pressure, the higher the stress and strain are on the aortic wall, which translates into a higher risk of aneurysm expansion and potential rupture.
Summary
Aortic aneurysms are localized enlargements of the aorta (bulge) within the chest or abdomen. Many factors cause these aneurysms but result in a weakening of the aortic wall. This degenerative process can lead to rupture of the aorta, resulting in massive internal bleeding and death.
To Learn More, Check Out My Books
BadAorta Volume One: Aortic Dissections: A Deep Dive Into Aortic Disease, It's Treatment And The Latest Research
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Risk Factors For Developing Aortic Disease (Second Edition): A Tool For Patients and Physicians
