Learn more about aneurysms, pseudoaneurysms and dissections in vascular Ehlers-Danlos Syndrome
NORMAL BLOOD VESSELS
Blood vessels carry blood away from and back to the heart. Your arteries are responsible for carrying oxygenated blood away from the heart to the tissues of the body. Your veins carry deoxygenated blood back to the heart, where it will get reoxygenated (by the lungs) and then go back out to the tissues again by the arteries. Issues with our arteries are what cause the majority of events in vascular Ehlers-Danlos syndrome. An artery consists of three layers: the intima, media and adventitia. The intima is the innermost layer and is only a few cell layers thick. The media is the middle layer of the blood vessel and is made up of smooth muscle cells. These muscle cells function by providing elasticity (enabling the vessel to expand and contract under pressure). The adventitia is the outermost layer, which is mainly made up of connective tissue.
Aneurysms take place in the arteries of the body which carry blood away from the heart. A true aneurysm is defined as a dilation of the blood vessel wall in which all three layers of the vessel are intact and dilated. As an aneurysm forms it makes the blood vessel weaker and more likely to rupture, which is the most serious complication of aneurysms. An aneurysm rupture is a life threatening event requiring immediate medical care. When an aneurysm is formed it may be asymptomatic (and picked up on imaging) or it may cause pain in the area of the aneurysm.
A pseudoaneurysm means a 'false' aneurysm. They are a contained rupture of a blood vessel. In the area of the pseudoaneurysm, all three layers of the blood vessel wall are disrupted and absent. Blood flows into this space outside the blood vessel, but it is contained within this space. The most serious complication of a pseudoaneurysm is still a rupture of the artery causing bleeding.
ARTERIAL DISSECTIONSArterial Dissections are tears in the inner most layer of the artery (the intima). This disrupts the normal flow of blood through the artery. Now, blood has two places it can flow: the normal passageway (called the 'true lumen'), in which case it flows like usual. The second passageway is outside the tear-- so blood is flowing inbetween the layers of the blood vessels; the intima is on one side while the rest of the blood vessel (made up of the media and adventitia) are on the other side.
Arterial dissections cause a variety of symptoms or can be entirely asymptomatic. The symptoms depend on the anatomic location of the dissection and the extent of the tear in the blood vessel wall. A risk of dissections is a compromise of blood flow to the organ which that blood vessel is meant to provide blood. For example, dissection of the splenic artery can compromise blood flow to the spleen. Meanwhile a dissection of the renal artery (which carries blood to the kidney) can cause a compromise of blood flow to the kidney. One final complication of dissections can be the subsequent formation of an aneurysm within the area of the dissection.