The modified Bentall procedure for aortic root replacement

AORN Journal,  July, 2006  by Cecile Cherry,  Starla DeBord,  Carol Hickey

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[FIGURE 3 OMITTED]

AORTIC DISSECTION. The term aortic dissection refers to a tear in the intimal wall of the vessel, creating a false lumen that allows blood to accumulate between the tunica intima and the tunica media. Systemic blood pressure forces more blood into this false lumen with each heartbeat, enlarging the area of dissection. Untreated, the dissection will continue to enlarge, creating possible complications, such as

* aortic thrombus formation,

* compromised systemic circulation,

* rupture of the weakened aortic wall, or

* cardiac tamponade.

Patients may present with signs of shock because of decreased circulating blood volume or sudden onset of stroke or paralysis as a result of disruption of blood flow to the brain or spinal cord. Dissections of the ascending aorta may alter the normal anatomical structure of the aortic root, resulting in dysfunction of the aortic valve and disruption of the flow of blood to the coronary arteries. (15-17)

INCIDENCE. The incidence of all thoracic aneurysms is estimated to be 10.4 cases per 100,000 people annually. (18) Thoracic aortic aneurysms occur most frequently in the ascending aorta (ie, 50%), whereas only 40% occur in the descending aorta, and the remaining 10% occur in the aortic arch. (5,15) Aortic dissection affects two in 100,000 people in the United States annually, most commonly men who are 40 to 70 years of age. (19) Factors associated with developing an aortic aneurysm or aortic dissection are presented in Table 1.

SYMPTOMS. Often thoracic aortic aneurysms are asymptomatic and are discovered only by testing for other conditions. Symptoms may not occur until the aneurysm grows large enough to compress adjacent structures in the chest, at which point patients may complain of chest or back pain. (3,18) Symptoms specific to aortic root aneurysm caused by aortic regurgitation include

* cough,

* diastolic murmur,

* dysphasia,

* dyspnea on exertion,

* fatigue,

* orthopnea,

* palpitations,

* paroxysmal nocturnal dyspnea, and

* widened pulse pressures. (5,20)

Symptoms of aortic dissection include sudden onset of severe chest pain, which may radiate to the back and often is described as a "ripping" or "tearing-like" pain. Clinical signs of acute aortic insufficiency or aortic regurgitation resulting from an aortic root dissection are the same as those caused by aortic root aneurysm. (16)

DIAGNOSIS

Chest radiography may reveal an aortic aneurysm, usually by the presence of a widened mediastinum; however, it is not always possible to distinguish an aortic aneurysm from a mass. In some patients, an aortic root aneurysm might be obscured by the cardiac silhouette and therefore not be visible on a chest x-ray. Patients with aortic incompetence may have an enlarged cardiac silhouette. (18) Transthoracic or transesophageal echocardiography can be used to diagnose pathology of the aortic valve and aorta. Contrast-enhanced computed tomography can be used to diagnose the presence, location, and size of an aortic aneurysm. Cardiac catheterization with aortography provides accurate diagnosis of the presence and severity of an aortic root aneurysm. If coronary artery disease is demonstrated during the cardiac catheterization, the surgeon probably will elect to perform a coronary artery bypass at the time of the aneurysm repair. (9)