An aortic dissection is a tear in the aortic intima through which blood enters and subsequently dissects distally along the plane between the intima and media of the vessel, creating a true and false lumen in the aorta.
Hypertension and Marian’s syndrome are the most common predisposing factors. Type A disections originate in the ascending aorta, usually with a few centimeters of the aortic valve, and either extend around the aortic arch into the descending aorta(type to the ascending T type III) dissections involve only the descending orta and originate just distal to the origin of subclavian artery at the site of the ligamentum arteriosum. Patients with an acute aortic dissection usua present with sudden, severe chest pain, which may be tearing” in quality.
The pain may be substernal, classically radiating to the interscapular area. Proximal dissections may involve the aortic valve, resulting in acute aortic insufficiency; may dissect into a coronary artery(most commonly the right coronary artery), producing acute myocardial ischemia or infarction; and may rupture into the pericardial space, resulting in tamponade As the dissection progresses distally, involvement of the subclavian, carotid, mesenteric, renal, and iliac arteries may result in pulse discrepancies or in cerebral, mesenteric, renal, or limb ischemia. The chest roentgenogram frequently demonstrates a widened mediastinum, although a normal mediastinal shadow does not exclude the diagnosis.
The extent of dissection can be visualized with TEE, contrast CT, or MRI. In the hemodynamically unstable patient with suspected aortic dissection, TEE is the study of choice. Once the diagnosis of aortic dissection is suspected.
treatment should be instituted immediately. All patients should receive blocker therapy even if they are normotensive.