labetalol and aortic stenosis

furfur said:

anyone have a problem giving labetalol for HTN in someone with moderate stenosis of the aortic valve?

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No - why?
The problem I think is not labetolol - could be any agent IF is not titrated very carefully. One idea is to choose short acting short action vasodilators....
2win

Then why give a hypotensive drug?
Or you're treating hypertension and you're going to decrease afterload or you don't need to but then why would you give it?

The key point here is titrate gradually whatever you give.
In a severe aortic stensosis you would be theoretically concerned about 2 issues with Labetalol:
1- Vasodilation
2- Negative inotropic effect
Both these issues could put the patient in acute heart failure and even trigger acute coronary ischemia.
In a moderate AS you are probably OK as long as you go slow.

Hydralazine is the one more people are worried about with AS. Moderate AS, like others have said, is probably not too much of an issue.

I wouldn't have a problem with labetalol if BP was sky high (180/100). I wouldn't bee too aggressive though.

proman said:

Hydralazine is the one more people are worried about with AS. Moderate AS, like others have said, is probably not too much of an issue.

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I was just ruminating on this the other day. The "aortic stenosis death spiral" is, to me, a great way to learn and teach about coronary circulation, hemodynamics in general (MAP/CO/SVR), preload/afterload etc etc. Sounds like something to be super-afraid of, and it seems like something that's taught over and over.

And yet, in reality...

I have seen patients with moderate and severe AS get their coronaries and myocardium run through the wringer in the ICU, septic as hell, dehydrated, diastolics in the 30's-40's, getting propofol, and then later, once they're outta the woods, getting pounded with simultaneous beta-blockade, ACE inhibitors, and diuresis, all while on positive-pressure ventilation. Not a blink, not a troponin bump, just as if they had normal hearts.

Is our fear/caution wrt AS overstated? Is the heart that resilient? Or are my experiences skewing my perspective?

Since starting this cardiac anesthesia fellowship, I have learned to worry a lot more about aortic regurgitation than aortic stenosis. The AS death spiral is a good theoretical construct, but even the truly critical ones seem to be much easier to manage than I thought they would be when learning about them in residency.

I think this is because it is comparatively easy to predict the correct method of managing preload, afterload, and contractility etc when presented with AS. Aortic regurg is theoretically more forgiving, but it is harder to predict the actual clinical effects of hemodynamic variations.

It is easier to defeat the enemy when you know their tactics in advance.

- pod

fakin' the funk said:

Is our fear/caution wrt AS overstated? Is the heart that resilient? Or are my experiences skewing my perspective?

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I don't think it's necessarily overstated. I just think that critical AS is a much different disease than moderate AS. I remember doing a colonoscopy on a lady one night on call. She was scheduled to have an AVR for valve area of 0.5cm2. Had a history of some GI bleeding, so the surgeon wanted a screening colonoscopy before fully heparinizing. I was giving 10-20mg of propofol at a time. No problems, but every time her SBP would drop below 120 she's go from sinus rhythm to ventricular bigeminy. A few cc's of phenylephrine and the ectopy disappeared. That patient probably didn't have far to go.

But, I'd say that a valve area of 1.0 is much different than 0.5

fakin' the funk said:

I have seen patients with moderate and severe AS get their coronaries and myocardium run through the wringer in the ICU, septic as hell, dehydrated, diastolics in the 30's-40's, getting propofol, and then later, once they're outta the woods, getting pounded with simultaneous beta-blockade, ACE inhibitors, and diuresis, all while on positive-pressure ventilation. Not a blink, not a troponin bump, just as if they had normal hearts.

Is our fear/caution wrt AS overstated? Is the heart that resilient? Or are my experiences skewing my perspective?

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I agree with what youre saying overall, I think on hearing the word AS people instantly think of one of those patients that we all meet that actually are constantly on deaths door. Most people with a diagnosis of AS seem to be as you describe. At some point, likely in the very near future, you'll come accross the real deal...they will present themselves very quickly and so long as you know ahead of time what youre dealing with you can work your way through it...like proman was describing.

periopdoc said:

Since starting this cardiac anesthesia fellowship, I have learned to worry a lot more about aortic regurgitation than aortic stenosis. The AS death spiral is a good theoretical construct, but even the truly critical ones seem to be much easier to manage than I thought they would be when learning about them in residency.

I think this is because it is comparatively easy to predict the correct method of managing preload, afterload, and contractility etc when presented with AS. Aortic regurg is theoretically more forgiving, but it is harder to predict the actual clinical effects of hemodynamic variations.

It is easier to defeat the enemy when you know their tactics in advance.

- pod

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just to play the devils advocate perhaps you feel that way now because of how nitoriously hard end stage AI pts are to get off pump and progress through their ICU course. The AI your seeing is probably the absolute worst of the worst; whereas youre probably doing a handful of AS patients every week.