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This week we learned that the keyboardist of Depeche Mode, Andrew “Fletch” Fletcherdied last May due to a aortic dissection. Aortic dissections are relatively rare compared to other cardiovascular diseases, such as heart attacks, but their consequences are often very negative.
The aorta is the main artery of the body. It carries oxygen- and nutrient-rich blood from the heart to the rest of the body, providing our tissues with everything they need to function properly. An aortic dissection is a tear of the innermost lining of the aorta. The inner lining is a single layer of highly specialized cells called endothelial cells, which ensure that blood remains in its liquid form as it flows through the body’s blood vessels.
When damage occurs to the endothelial layer, high-pressure blood passes through the intimal layer and into the next layer, the medial layer, literally dissecting a path to the outer layers of the aorta.
If left undiagnosed and untreated, this can lead to complete failure of the aortic wall and leakage of blood from the vessel into neighboring structures and tissues. This stretches the aorta and changes its biomechanical function, which may further contribute to the disease process.
The diversion of blood towards the tear can hinder the flow of the organs located below, in some cases preventing the supply to some of them. The tear also changes blood flow through the vessel, which can cause further damage to specialized cells in the endothelial lining.
rare disease
aortic dissections affect approximately three to four people in 100,000. And they are twice as common in the ascending part of the aorta compared to the descending part.
It is important to know where an aortic dissection occurs, as this can influence how a person is affected, the treatment of the disease, and their chance of survival. Dissections involving the ascending aorta are known as type A, while those involving the descending aorta are type B.
A person’s gender also influences the type of aortic dissection they may develop, as well as the likelihood of developing it. In the case of mensaortic dissection usually occurs around 60 years oldwhile in the women usually occurs later around 65 years old. Type A dissections are twice as likely in men as in women.
Aortic dissections are mainly linked to two factors: genetic conditions and lifestyle, which affect the heart and blood vessels. For example, the bad nutrition and the smoking they can cause hypertension (high blood pressure), which increases the chance that specialized cells lining the blood vessels will be damaged. This makes it much more likely that a person will develop an aortic dissection.
Another important lifestyle factor that makes a person more likely to develop aortic dissection is cocaine use. This increases heart rate and blood pressure, while decreasing the amount of blood that passes through the arteries that supply the heart.
Cocaine use not only makes a person more likely to develop an aortic dissection later in life, but it can also trigger an aortic dissection.
There is a series of genetic diseases which are also associated with an increased risk of aortic dissection. The most common is a disease called marfan syndrome, which affects approximately one in 5,000 people. This disease prevents people from producing enough of a key protein that helps give blood vessel walls their structure and elasticity.
Without a sufficient amount of this protein, the walls of the blood vessels weaken and are at greater risk of dissection or rupture. People with Marfan syndrome are also more likely to develop aortic dissection at a younger age, usually around 38 years of age.
Trauma can also lead to dissection, with traffic accidents being one of the main causes. They can cause the beginning of a dissection, or a spontaneous rupture of the aorta.
Possible treatments
Symptoms of aortic dissection include pain, often described as a tear in the chest, abdomen, or back. In cases where people are known to have predisposing conditions, they are medically monitored or managed, usually with drugs such as beta-blockers and the antihypertensives, which lower blood pressure and decrease the risk of damage to the endothelial lining. This type of treatment is only really appropriate for type B dissections. Type A almost always requires immediate surgical intervention.
In people with suspected aortic dissection, or who already know about it, it is essential to detect it early. Generally, a CT to diagnose the disease and the final phase of treatment is surgical repair or replacement of the defective part of the aorta. But the results of this procedure are mixed, since the survival of surgery for a type A dissection is usually around 52-94% at one year after the operation and 45-88% at five years. For type B, there is similar variation in survival, at 1 year (about 56-92%) and at 5 years (48-82%).
In type B dissections, antihypertensive medications can sometimes be used to stabilize the patient before surgery, but this is not always possible. A dissection is a serious disease and does not repair itself.
Due to the severity and possible poor outcomes of aortic dissection, it is important modify any lifestyle factors that may contribute to increased risk, and exercise, follow a healthy and balanced diet and stop smoking. It’s also important to make sure any underlying health conditions that may pose a higher risk (such as high blood pressure) are medically monitored.
Adam Taylor. Professor and Director of the Clinical Anatomy Learning Centre, Lancaster University.
This article was originally published on The Conversation.
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