What is normal pressure gradient ?

[Paleowoman]

Can someone tell me what a normal pressure gradient is please ? Trying to explain things to other people and I've been unable to find this out.

Anne

 

[Julian]

I'm no doctor, and I hope I'm understanding your question right, the normal pressure is somewhere around 0. Normal hearts have no pressure or very little measurable pressure. I think... someone slap me if I'm wrong. I think that why On-X tries to go around bragging on some of there valve sizes have single digit pressure gradients.

 

[Bina]

Taken from Wikipedia:
These calculations would be found on an Echocardiogram report.

Severity of aortic stenosis
Degree of aortic stenosis

Mean gradient(mmHg).............. Aortic valve area (cm2)

Mild aortic stenosis <25 -------------- >1.5
Moderate aortic stenosis 25 - 40 -------1.0 - 1.5
Severe aortic stenosis >40 ------------< 1.0
Critical aortic stenosis >70 ------------< 0.6

 

[Paleowoman]

Hi Julian - So I guess that means a normal pressure gradient is 9 mm/Hg or less ?

Hi Bina - Yes I know the pressure gradients if you have aortic stenosis, I wanted to find out what the pressure gradient is for someone who has a normal heart and valves so I can get things in perspective when talking about aortic stenosis

Thanks,
Anne

 

[Julian]

Hi Julian - So I guess that means a normal pressure gradient is 9 mm/Hg or less ?

Anne

I would go as far as saying normal gradient is around zero. I remember reading that people with no valve issues have really no measurable pressure in heart. So I guess you can say normal is 0.

 

[Julian]

After valve replacement it seems people never have truly "normal" pressure levels. Its fixes the problem so its really a non issue but on paper we are never "normal" again as far as pressure is concerned. No man made valve is perfect. Most people with valves disease have some serious measurable pressure going on, after replacement or repair this number gets cut like 70 to 90 percent.

 

[Mentu]

PG, as I understand it, the pressure gradient is essentially a comparison of blood pressure inside the heart on one side of a heart valve with the blood pressure on the outside of the valve. In the best of all possible worlds, the pressure should be the same on both side so there is no difference or "gradient". If there is a difference, something is restricting blood flow. For most of us, the restriction is caused by the calcification of a heart valve which reduces the size of the valve opening (valve area). The smaller the valve area when blood flows through it, the greater the difference in pressure from one side of the valve to the other. As the area of the valve decreases, the heart must work harder to push the necessary amount of blood through the smaller opening. Over time, this need to compensate causes the heart muscle to enlarge and eventually weaken. As I understand things, one's symptoms are largely caused by the loss of proper blood flow and the stress on the heart as it compensates for the diseased valve.

As a heart valve degrades causing the opening (valve area) to become smaller, the pressure gradient increases. Valve area is measured in square centimeters (cm2) and pressure is measured in millimeters of mercury (mmHg). Usually, you will see a measure of both "mean" and "peak" pressure gradient.

Before surgery, my valve area was 0.70 cm2. For a normal adult it should be something around 2.5 to 3.0 cm2.

My pressure gradients were:

Before surgery:

Valve Area: 0.70 cm2
Mean - 61.4 mmhg
Peak - 127.5 mmhg

After surgery:
Valve Area: 2.9 cm2
Mean - 18 mmhg
Peak - 35 mmhg

Does that make sense to you?

Larry

 

[Julian]

Makes sense to me Mentu, thanks!

 

[Paleowoman]

Thanks Larry - makes sense

 

[bivalve1]

Hi Anne, as I understand it there isn't really a pressure gradient through the valve if it is 'normal'. When the valve becomes narrowed by stenosis, the pressure inside the valve starts to become higher than the pressure outside the valve as the heart is squeezing the blood through a narrower aperture. If you listen to a heart beat with a murmur caused by this, you can hear a sort of 'swoosh' after the click. Listen to a normal heartbeat and there is no 'swoosh'. This helped me to picture the pressure gradient.

 

[bivalve1]

Sorry, I see you had lots of replies saying the same thing!! Will look at date next time. Have you had the op?

 

[Paleowoman]

Hi bivalve1,

Thanks for your reply, no worries that I've had others ! Not had my op yet - still in the waiting room,

all the best,

Anne