Afterload

It makes perfect sense.

So a high afterload is going to worsen aortic regurgitation.

Afterload reduction can be helpful.

It can improve forward flow, reduce the regurgitant fraction, the fraction of blood that's regurgitating backwards, and this can then lower left ventricular end-eye stock pressure and decrease pulmonary congestion.

All right, so unlike aortic stenosis where you have a fixed lesion, so afterload reduction is not going to help you much.

Bradycardia is dangerous in these patients because it prolongs the regurgitant time.

Avoid bradycardia.

Afterload reduction can help these patients.

The response to the passive leg raise gives us more useful information than a single CVP number because we're watching what the heart actually does when preload changes.

Okay, now let's talk about afterload.

Afterload is the load the ventricle has to overcome to eject blood.

So for the left ventricle, think about the pressure and resistance between the ventricle and the systemic circulation.

Picture squeezing a blood pressure cuff tightly around someone's arm.

Preload, which needs to be adequate but not excessive, because you can over-distend it.

Afterload, that's your oxygenation, your carbon dioxide, avoiding acidosis and inhaled nitric oxide.

Contractility, inotropes.

And coronary perfusion, which means keeping the systemic pressure up.

The best option depends on your patient's physiology and dynamic response to their own evolving pathophysiology.

But if they have enough blood pressure to tolerate it, Afterload reduction via vasodilators are ideal, but if they don't have enough blood pressure to work with, vasopressors might be needed to ensure perfusion to all the other organs, and inotropes might be beneficial too.

If it's going to be a bit until you get to the operating room, a temporary mechanical circulatory support may buy additional time by supporting systemic perfusion and, depending on the device, reducing left ventricular afterload or directly just unloading the ventricle.

And finally, this is scary for the nurse.

That ventricle now has to eject against an inflated balloon sitting in its aorta.

Afterload goes up dramatically, isovolumetric contraction is prolonged, and myocardial oxygen consumption climbs.

On the trace, you see a widened, elevated end-diastolic pressure and a poor assisted systolic upstroke.

So of the four, early inflation and late deflation are the harmful ones.