Aortic Disease In Men vs Women: What Should You Know About Gender Differences And Aortic Aneurysm?

The biggest and most important artery in your body, the aorta, transfers oxygen-rich blood from the heart to almost all parts of your body via its smaller branches. However, due to many factors, whether caused by genetic diseases or an unhealthy lifestyle, the aortic wall may weaken, causing that part of the aorta to permanently increase in diameter. This local expansion of the aorta is called an aortic aneurysm.

Generally, aortic aneurysms don’t show any symptoms, especially when they are relatively small. However, even if symptoms do develop, they are mostly non-specific, such as abdominal or back pain, coughing, or a pulsating sensation in your belly area.

If the aneurysm continues to expand, the aortic wall will gradually become thinner, until the moment it bursts. This is known as an aortic rupture, and it’s an urgent medical condition, because if the massive internal bleeding is not immediately treated, the effects can be lethal. Unfortunately, almost half of patients with a ruptured aneurysm will not survive, even if surgery was done in time.

Several scientific works have tried to explain this difference, and the results mainly have to do with anatomical differences, hormone status and social habits.

Aortic aneurysm has a slightly different structure in females

The aortic wall is made of three layers:

• The smooth inner layer (intima)
• The elastic middle layer (media)
• The outermost layer (externa or adventitia), made mostly out of collagen fibers

When the cells that make up the aortic wall start to deteriorate, the aorta begins to lose its flexibility, eventually leading the aortic wall to expand enormously, causing an aneurysm.

The aortic wall in women with smaller aneurysms (< 4cm in diameter) is shown to be made out of a thicker external layer, as well as a thinner middle layer than in men. Although this is not particularly significant on its own, the gender differences in hormone regulation might have an impact on aneurysm development.

Female sex hormones provide protection against aortic wall destruction

Women seem to have a more elastic aorta than men. This is most likely because of the fact that estrogens (female sex hormones) lower the ratio of collagen to elastin, unlike testosterone (male sex hormone), which increases the amount of collagen, making the "male" aorta stiffer, and therefore more susceptible to aneurysm formation. This probably explains why aortic aneurysm is four to five times more common in men.

The proteins in the aortic wall are constantly being destroyed and repaired in the process of tissue remodeling. The enzymes which degrade proteins are called matrix metalloproteinases (MMP). Estrogens also inhibit the production of these enzymes, which in turn prevents the destruction of proteins that form the aortic wall.

Aortic rupture is more likely to happen in women

Although aortic aneurysm is five times more common in men, the risk for aortic rupture is up to three times higher in women. There are more women who were admitted as patients and operated on, than in symptomless patients with this diagnosis.

Other risk factors for aortic rupture include:

• The size of the aneurysm (larger than 5,5cm). Keep in mind that smaller aneurysms in women are more likely to burst. There is a significant difference in aneurysms smaller than 4cm, showing that same-sized aneurysms in women have increasingly thinner walls than in men. That means that smaller aneurysms in women are more likely to burst.
• Growth rate (more than 0,5cm in 6 months). There are studies that show that the aneurysm (both thoracic and abdominal) growth rate was faster in women than in men.
• Elevated blood pressure

Female smokers have the same risk of aortic aneurysm as men

Studies have shown that smokers have a 5.5 increased risk of developing an aortic aneurysm compared to non-smokers, and that female smokers have an astonishing nine-fold risk of developing an AAA than female non-smokers. However, the fact that the majority of the smokers on this planet are male probably explains why there are comparably fewer females with an aortic aneurysm.

Women are more prone to complications during aortic surgery

Unfortunately, women are almost twice as likely to die during aortic surgery. Also, there is 40 percent higher risk that women will develop complications earlier than men. The main reason for that is that the symptoms women develop can seem less serious, or manifest only when the aneurysm grows in size to the point where the operation becomes increasingly difficult.