History: Sudden onset of pain radiating to the back
Findings: Axial contrast-enhanced CT images through the chest reveal an intimal flap through the aortic lumen that originates near the subclavian artery and extends inferiorly down the thoracic aorta. The larger, false channel (fc) is is located in the posterolateral descending aorta. The ascending aorta is normal. No active extravasion of contrast material from the aorta is identified. In a different patient witht he same abnormality, an axial ECG-gated T1-weighted MR image also demonstrates an intimal flap.
Diagnosis: Thoracic Aortic Dissections (DeBakery type III or Stanford type B)
Aortic dissection is one of the acute aortic syndromes and a type of arterial dissection. It occurs when blood enters the medial layer of the aortic wall through a tear or penetrating ulcer in the intima and tracks along the media, forming a second blood-filled channel within the wall.
Dissection of the aorta occurs when a pathologic communication develops between the true aortic lumen and the aortic wall. The most common predisposing factor to the development of aortic dissection is hypertension. Other predisposing factors include Marfan and Ehlers-Danlos syndromes, pregnancy trauma, aortic valve disease, and coronary artery bypass surgery. Dissections that involve the ascending aorta (DeBakery types I and II and Stanford type A) may lead to rapid death because of rupture into the pericardium, acute valvular insufficiency, or coronary artery occlusion. Therefore these types of dissections are managed with emergent surgery. Dissections that involve only the descending aorta distal to the left subclavian artery (DeBakery type III, or Stanford type B) are usually managed medically by control of the patient’s hypertension.
- Emergent surgery is required for Stanford type A dissections
- Always check for aortic rupture and branch vessel involvement
- If dissection involves the ascending aorta, look for pericardia hematoma.