Aortic Dissection

Aortic dissection occurs when blood dissects between the middle and outer two thirds of the aortic media, creating a blood filled channel within the aortic wall.37 The process usually arises in the ascending aorta and is manifested by an intimal tear, a necessary component of a dissecting aortic aneurysm. The tears have sharp edges and run transversely or longitudinally rather than obliquely. A combined longitudinal and transverse tear produces T- or cross-shaped tears. The tear tends to arise in relatively normal appearing areas of the aorta. In some case, the tears are seen to be preceded and arise in areas of intramural hematoma. The dissection then proceeds peripherally down the aorta. It usually breaks out again into the lumen of the aorta. It might, however, rupture into the pericardial sac. The predisposing factors are hypertension, heredity and inflammation. In Marfan's syndrome, there is both dilatation and dissection of the aorta.38 Marfan's syndrome affects fibrillin, a glycoprotein that sees to the adhesion and alignment of the sheets of collagen in the aorta. Fragmentation of the elastic fibers results in weakening of the wall and dissection. Focal areas of cystic medial necrosis may be seen.

The term aortic dissection is often used to describe rupture of the aorta due to simple dilatation rather than true dissection. Genetic abnormalities of the collagen, such as those found in osteogenesis imperfecta and Ehlers-Danlos, lead to dilatation of the aorta. This, in turn, can result in rupture at the site of the aneurysm.

Familial degeneration of the aortic media in the absence of any of the well-characterized diseases of the connective tissue can occur. These cases show cystic medial necrosis. Most individuals with dissection, however, have none of the aforementioned conditions. What they do have is hypertension. Hypertension is the most important risk factor in developing aortic dissection.

Weight lifting and use of cocaine have been associated with aortic dis-section.38,39 In regard to cocaine, the individuals tend to be men, long-term cocaine users, and have a history of hypertension or idiopathic cystic medial necrosis.39 The dissection occurred shortly after recent use of cocaine. The weight lifters may have had predisposing cystic medial necrosis.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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