aortic dissection

[Jenny_94]

I just saw a case problem about aortic dissection. The patient's bp was asymmetric. The left arm blood pressure was higher than the right arm. How is this possible? Does anyone know the pathophysiology?

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[dfib slim]

Do you mean as opposed to the right being higher than the left? Maybe a DeBakey Type II. With a dissection, depending on which aortic branches are affected, you'll get differing BP in the extremities.

 

[Jenny_94]

Yes i mean that both arms had high pressure but the left arm had a higher pressure. Well which artery do you think has been affected? How can it cause a higher pressure on the left arm?

 

[dfib slim]

If you know your anatomy, blockage of the brachiocephalic artery will lead to a lower BP on the right compared to the left.

 

[Big N Tasty]

Dissections commonly occur in the ascending arch of the aorta. Thus, you're more likely to block the brachiocephalic trunk (right) with relatively normal flow to the left branches.

 

[Instatewaiter]

What you have there is a type A dissection with the dissection flap going up the innominate with true lumen supplying the left subclavian.

 

[Jenny_94]

Thanks a lot! I understand now!

 

[TypeADissection]

What you have there is a type A dissection with the dissection flap going up the innominate with true lumen supplying the left subclavian.

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Also remember that Type A's are surgical emergencies that require open operations. Type B's since they take place distal to the subclavian can be managed with blood pressure control. Drug of choice will be a beta blocker (esmolol).