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Aneurysms Maryam Moossavi Dec 2015

Introduction…  An aneurysm is an abnormal bulge in the wall of an artery.aneurysm  Normally, the walls of arteries are thick and muscular, allowing them to withstand a large amount of pressure.arteries  Occasionally, however, a weak area develops in the wall of an artery. This allows the pressure within the artery to push outwards, creating a bulge or ballooned area called an "aneurysm."

 Aneurysms can form in any blood vessel, but they occur most commonly in the aorta (aortic aneurysm).bloodaortaaortic aneurysm  Aortic aneurysms can occur in two main places:  Abdominal aortic aneurysms occur in the part of the aorta that passes through the middle to low abdomen.abdomen  Thoracic aortic aneurysms occur on the aorta as it passes through the chest cavity. These are less common than abdominal aneurysms.

Aneurysms increase the risk for:  Atherosclerotic plaque formation at the site of the aneurysm. This causes further weakening of the artery wall.  A blood clot may form at the site and dislodge, increasing the chance of stroke.blood clotstroke  Increase in the size of the aneurysm, causing it to press on other organs. This may cause pain.cause pain  Aneurysm rupture. Because the artery wall thins at this spot, it is fragile and may burst under stress. The rupture of an aortic aneurysm is a catastrophic, life- threatening event.

What Causes Aortic Aneurysms?  Atherosclerosis, or hardening of the arteries, which weakens arterial walls. Atherosclerosis  Hypertension (high blood pressure). Hypertensionhigh blood pressure  Local injury to the artery.  Congenital abnormality.  A number of conditions, such as Marfan syndrome or bicuspid aortic valves are present at birth and can cause weakness of the artery walls.Marfan syndromeweakness  Aging  Syphilis used to be a common cause of thoracic aneurysms, but it is no longer as common. Syphilis

Further anatomy  Shapes of aneurysms

 Aneurysms involving the abdominal aorta are typically associated with atherosclerosis.  Aneurysms involving the thoracic aorta have many causes, including congenital abnormalities in the structure of the aortic wall.  Because aortic aneurysms typically do not produce symptoms until they are large, the diagnosis is often not made until a rupture or dissection occurs.

What Are the Signs and Symptoms of an Aneurysm?  The signs and symptoms of an aortic aneurysm depend on the type and location of the aneurysm. Signs and symptoms also depend on whether the aneurysm has ruptured (burst) or is affecting other parts of the body.  Aneurysms can develop and grow for years without causing any signs or symptoms. They often don't cause signs or symptoms until they rupture, grow large enough to press on nearby body parts, or block blood flow.

Diagnostic Tests and Procedures  Ultrasound and Echocardiography  Computed Tomography Scan  Magnetic Resonance Imaging  Angiography

THORACIC AORTIC ANEURYSMS  A thoracic aortic aneurysm (TAA) may not cause symptoms until it dissects or grows large. Symptoms may include:  Pain in your jaw, neck, back, or chest  Coughing and/or hoarseness Coughing  Shortness of breath and/or trouble breathing or swallowing

THORACIC AORTIC ANEURYSMS  MARFAN SYNDROME  The hallmark of MFS is abnormality of the medial layer of the aortic wall, characterized by fragmentation and disorganization of the elastic fibers, a generalized loss of elastin content.  The mechanical properties of the aorta are primarily a function of the elastic fibers within the media, so loss or abnormalities of elastin could weaken the tensile strength of the aortic wall.

 The most threatening consequence of MFS is dilatation of the aortic root and the ascending aorta, which, if untreated, can result in potentially fatal aortic dissection or rupture.  The second proposed mechanism of the pathogenesis of MFS is an altered homeostasis of the microfibril.

 The investigators hypothesized that microfibrils may be important in the homeostasis of the aortic wall, and in the absence of proper microfibril development, the aortic media is unable to sustain the hemodynamic stress to which it is subjected, eventually leading to aortic dilatation.  The disruption of the elastic network may then be a secondary event.

 An increase in fibrillin proteolysis is the third mechanism proposed of the pathogenesis of MFS.  It is recognized that calcium binding to the calcium-binding epidermal growth factor-like (cbEGF) domains of fibrillin is essential for the proper assembly and integrity of the microfibrillar aggregates, and that calcium may protect wild- type fibrillin from proteolysis.

 Bicuspid aortic valve  Bicuspid aortic valve is often associated with dilatation of the aortic root or ascending aorta and may progress to frank thoracic aortic aneurysms and aortic dissection.  The thoracic aortic aneurysms associated with bicuspid aortic valve typically demonstrate accelerated degeneration of the aortic media.

 Familial thoracic aortic aneurysm syndrome  It is recognized that cases of thoracic aortic aneurysms in the absence of overt connective tissue disorders are often familial in nature and reflect a familial thoracic aortic aneurysm syndrome.

CXR

CT-contrast

Abdominal aortic aneurysms  abdominal aortic aneurysms (AAAs) are typically associated with aging and atherosclerosis.  Gender plays a role; men are 10 times more likely than women to have an AAA of 4 cm or greater.  However, women with an AAA have a significantly greater risk of rupture than men.

Hallmarks…  First, the pathologic hallmark seems to be destructive remodeling of the elastic media of the aortic wall, including progressive degradation of the fibrillar matrix proteins.  Second, evidence of an infiltration of inflammatory cells exists, including B lymphocytes, T lymphocytes, and macrophages.  Third, there is increased immunoreactivity for elastolytic matrix metalloproteases (MMP), particularly MMP-2, MMP-9, and MMP-12.

 Most abdominal aortic aneurysms (AAAs) develop slowly over years. They often don't cause signs or symptoms unless they rupture. If you have an AAA, your doctor may feel a throbbing mass while checking your abdomen.  A throbbing feeling in the abdomen.  Deep pain in your back or the side of your abdomen.  Steady, gnawing pain in your abdomen that lasts for hours or days.

 If an AAA ruptures, symptoms may include:  sudden, severe pain in your lower abdomen and back;  nausea (feeling sick to your stomach) and vomiting;  constipation and problems with urination;  clammy, sweaty skin;  light-headedness;  and a rapid heart rate when standing up.

CT Scan

Arteriogram

Ultrasonogram

MRI

Plain Abdominal X-ray

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