Aortic Dissection Flashcards
What is an aortic dissection?
An aortic dissection is a life-threatening condition where there is a tear in the intimal layer of the aortic wall, leading to blood entering the media and creating a false lumen.
What are the two main classifications of aortic dissection?
The Stanford classification divides aortic dissections into Type A (involving the ascending aorta) and Type B (involving the descending aorta only).
What is the most common site of an aortic dissection?
The most common site is the ascending aorta, just distal to the aortic valve.
What are the risk factors for developing an aortic dissection?
Risk factors include hypertension, connective tissue disorders (e.g., Marfan syndrome, Ehlers-Danlos syndrome), aortic aneurysm, bicuspid aortic valve, and advanced age.
What are the typical symptoms of an aortic dissection?
Symptoms include sudden onset of severe chest or back pain, often described as tearing or ripping, radiating to the back, abdomen, or legs.
What are the common signs of aortic dissection on clinical examination?
Signs include blood pressure discrepancies between limbs, weak or absent peripheral pulses, new-onset aortic regurgitation murmur, and features of shock in severe cases.
What are the main causes of aortic dissection?
The main causes are chronic hypertension and connective tissue disorders, which weaken the aortic wall and predispose it to tearing.
What is the pathophysiology of an aortic dissection?
A tear in the intimal layer allows blood to enter the media, creating a false lumen that can propagate along the aorta, compressing true lumen flow and potentially leading to rupture or ischaemia of vital organs.
What imaging modality is the gold standard for diagnosing an aortic dissection?
CT angiography is the gold standard for diagnosing an aortic dissection due to its high sensitivity and specificity.
What other imaging modalities can be used to assess aortic dissection?
Other imaging options include transoesophageal echocardiography (TOE) and MRI, which can be used in certain cases, particularly if CT is unavailable.
What is the role of chest X-ray in diagnosing aortic dissection?
Chest X-ray may show a widened mediastinum or abnormal aortic contour, but it is not diagnostic and requires further imaging for confirmation.
What are the complications of an untreated aortic dissection?
Complications include aortic rupture, cardiac tamponade, organ ischaemia, stroke, and death.
What are the indications for emergency surgery in aortic dissection?
Emergency surgery is indicated for Type A dissections and for Type B dissections with complications such as rupture, malperfusion, or ongoing pain despite medical management.
What are the management priorities for a Type A aortic dissection?
Type A dissections require emergency surgical repair to prevent complications like cardiac tamponade, aortic regurgitation, and death.
What are the management priorities for a Type B aortic dissection?
Type B dissections are usually managed medically with blood pressure control unless complications arise, in which case endovascular or surgical intervention may be needed.
What are the goals of medical management in aortic dissection?
The goals are to lower blood pressure and reduce shear stress on the aortic wall, typically with beta-blockers and vasodilators.
What medications are commonly used in the management of aortic dissection?
Beta-blockers (e.g., labetalol or esmolol) are first-line, often combined with vasodilators like sodium nitroprusside to control blood pressure and heart rate.
What is the prognosis for patients with untreated Type A aortic dissection?
Untreated Type A dissections have a very high mortality rate, with up to 50% of patients dying within 48 hours.
What is the prognosis for patients with untreated Type B aortic dissection?
Type B dissections have a better prognosis than Type A, but complications like rupture or malperfusion can still lead to significant morbidity and mortality if untreated.
What are the potential long-term complications of aortic dissection?
Long-term complications include aneurysm formation, recurrent dissection, and chronic pain.
What is the role of follow-up imaging in patients treated for aortic dissection?
Follow-up imaging is essential to monitor for complications, such as aneurysm formation or recurrent dissection, and is typically performed with CT or MRI at regular intervals.
How does Marfan syndrome predispose to aortic dissection?
Marfan syndrome weakens the aortic wall due to defects in fibrillin-1, making it more susceptible to tears and dissections.
What are the key differential diagnoses for aortic dissection?
Differential diagnoses include myocardial infarction, pulmonary embolism, pericarditis, and oesophageal rupture.
What is the role of lifestyle modifications in preventing aortic dissection?
Lifestyle modifications, such as controlling hypertension, smoking cessation, and regular monitoring in high-risk individuals, can reduce the risk of aortic dissection.
What surgical techniques are used in repairing Type A aortic dissections?
Techniques include open surgical repair with graft replacement of the affected aorta, often involving replacement of the aortic valve if it is compromised.
