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Dissecting Aortic Aneurysms (Published September 22, 2003)

Dissecting aortic aneurysms are one of the most catastrophic emergencies known to cardiovascular medicine and surgery. The aorta is the largest blood vessel in the body and the one that leaves the heart itself and gives rise to almost all the arteries that feed the body's organs. The predisposition for the internal tearing of the lining of the aorta may be present and yet be ominously silent until the disastrous tear begins. The high pressure in the aorta generated by the heart then splits the lining of the aorta like a peeling onion as the pressure forces blood into the wall. The dissection of the aorta itself may give rise to severe pain, but symptoms may come from the blood vessels that get pinched off as the dissection progresses. These symptoms may involve the heart itself, the brain, the spinal column, internal organs or the extremities. Because so many possible manifestations can occur, the best diagnostic asset is a high index of suspicion.

The risk factors that significantly increase the possibility of a dissecting aortic aneurysm are rooted in the same risks that predispose one to the premature development of typical atherothrombotic vascular disease. Uncontrolled severe high blood pressure, cigarette smoking and blood fat abnormalities perhaps rank highest in the modifiable risk factors for dissections. There indeed are congenital or metabolic disorders that can weaken the lining of the aorta so that even normal blood pressures can cause dissection, but these are relatively uncommon. Traumatic injury to the chest such as blunt trauma or motor vehicle accidents can also create shear forces that can tear the lining of the aorta, but those mechanisms are driven more by fate than behavior or genes.

As I alluded to above, dissecting aortic aneurysms do not announce themselves until they tear the lining and start compromising blood vessels that create symptoms in the organs those arteries feed. If the tear wends its way such that the blood actually reenters the aorta, the patient has a chance to survive. If the tear burrows out of the aorta and causes bleeding into a body cavity or the sac around the heart, death is almost instantaneous. The time it takes to make the correct diagnosis, and then the time it takes to institute definitive surgical therapy are the markers of survival. I have had patients that died within moments of the dissection beginning, and a patient that has lived over seven years with nothing but aggressive drug (non-surgical) treatment.

The powerful and effective medications used to treat dissections are primarily blood pressure lowering drugs. In the setting of a dissecting aortic aneurysm, however, they are merely temporizing interventions to buy the patient and doctors time to make the diagnosis and get the operating room ready.

If an aortic dissection is suspected, the diagnostic tools that can provide the answer are many. Echocardiography, computed tomography, magnetic resonance angiography as well as contrast or dye angiography can lead to the correct diagnosis. The trick is having any one of those modalities available right now. Any delay increases the risk of death. Usually if my colleagues or I even think that a dissection is possible, we notify our cardiac or vascular surgeons to go on stand-by or to not start their next elective case until we have determined if an acute aortic dissection is present. If it is confirmed, the patient usually goes directly to the operating room. Do not collect $200 (even if it's a co-pay).

As has been the Ventura Heart Institute's mantra for almost twenty years, the best treatment for cardiovascular disease is its prevention. Barring prevention, then early detection is desirable so that aggressive and targeted therapies can be initiated. Therapies do not necessarily mean drugs, since lifestyle changes afforded by proper nutrition, exercise and weight management can have profound effects on cardiovascular risk factors. However, if therapeutic lifestyle changes are not effective, then supplemental drug management clearly has been shown to prolong quality and quantity of life.

 

 
   
   

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