Acute dissection of Descending Thoracic aorta and Nitropress

drlee · Jul 21, 2008

According to the 1994 ITE Question 65:

An elderly man has an acute dissection of the descending thoracic aorta. Which of the following antihypertensive therapies is most likely to extend the dissection?

a) esmolol
b) NTG
c) NTP
d) NTP + beta-blocker
e) Trimethaphan

Answer: C

I have no clue why. Anyone? 😕

ozzie20 · Jul 21, 2008

drlee said:
According to the 1994 ITE Question 65:

An elderly man has an acute dissection of the descending thoracic aorta. Which of the following antihypertensive therapies is most likely to extend the dissection?

a) esmolol
b) NTG
c) NTP
d) NTP + beta-blocker
e) Trimethaphan

Answer: C

I have no clue why. Anyone? 😕

Just a guess that because the nitroprusside can increase cardiac output, increasing bloodflow to an area of dissection can increase a tear. Again, only a guess.

anesonia · Jul 21, 2008

ozzie20 said:
Just a guess that because the nitroprusside can increase cardiac output, increasing bloodflow to an area of dissection can increase a tear. Again, only a guess.

I agree- I read not long ago that the increase CO causes more "sheer stress" on the dissection and can make it worse which is why the B blocker is necessary if you give NTP

pgg · Jul 21, 2008

drlee said:
According to the 1994 ITE Question 65:

An elderly man has an acute dissection of the descending thoracic aorta. Which of the following antihypertensive therapies is most likely to extend the dissection?

a) esmolol
b) NTG
c) NTP
d) NTP + beta-blocker
e) Trimethaphan

Answer: C

I have no clue why. Anyone? 😕

All of these are appropriate medications for reducing blood pressure in patients with aortic aneurysms, but a beta-blocker should precede administration of nitroprusside. Without a beta-blocker, the reflex tachycardia associated with nitroprusside will increase dP/dT and shear forces, potentially extending the dissection.

huktonfonix · Jul 23, 2008

just a clarification. SNP does not directly increase cardiac output. It does decrease the SVR/afterload which the heart has to pump against. This may lead to an increase in CO which as the previous poster stated increases the shear forces on the dissection.

Acute dissection of Descending Thoracic aorta and Nitropress

drlee

Senior Member

ozzie20

Full Member

anesonia

Full Member

pgg

Laugh at me, will they?

huktonfonix

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