BAV gradient vs EF

[derekzmom]

My son is 15 and has a BAV amoungst other heart issues that have been resolved with surgery in the past. For the past 7 years we have talked about having the Ross Procedure done. Last October (2012) we were told that it was time for surgery, had a cath done, got a surgery date, i asked a question about a "bail out" valve in case the Ross wasnt possible once they got in and was told by the cardiologist that they "hoped" the Ross might still be possible but he would more than likely end up with a mechanical valve. It was a bit of a shock, the reasons the surgeon gave made complete sense (due to scarring the tissue was compromised and the Ross only a 10% chance of working, fair enough) so we decided to postpone surgery until a later date. Now.... the cardiologist never talks about EF, only about gradient. Dereks gradient last year was about 65% across the valve, we were told that when he got to between 90-100%, it would be classed as severe and he would definitely need surgery. When he saw the cardiologist in September he told us that there was little change but that the gradient was about 75%... I was fully expecting that he tell us that Derek needed surgery this fall, but that wasnt the case. He told us that Derek was walking a "fine line" and wanted to follow him every 3 months.

Im not sure what the difference between gradient and EF is. Im waiting for a copy of the Echo report so I can ask my Internal medicine friend at work to decipher it for me. In the mean time does anyone have a simple explanation?

Thanks

Allison

 

[epstns]

Well, I'm not an expert - only another patient, but I can help with some general info. The gradient is also called the pressure gradient. This is often measured in mm Hg, millimeters of mercury, since that is the usual scientific unit of measure for all things related to pressure. (The barometric pressure on the weather report, for example.) The gradient is the difference in blood pressure from one side of the valve to the other. In the case of a BAV, which is often stenotic (calcified) or simply becoming thicker so it won't open properly, there is a difference in blood pressure between the two sides of the valve (before it and after). This is the gradient they are discussing. Here in the US, the medical societies have guidelines for evaluating the gradient. Ideally, there would be no difference in pressure across the valve, but in a malfunctioning valve there is a difference. I have long forgotten the specifics, but the chart shows "up to XX mm Hg is considered mild, from XX to YY mm Hg is considered moderate, etc." Basically, the gradient is a measure of how much extra effort the heart needs to expend in order to pump blood from the heart to the body, I have never heard of the gradient expressed as a percentage. Unless someone else has the data, I suggest a web search on "aortic valve gradient" or similar.

Ejection fraction (EF), on the other hand, I have always heard expressed as a percentage. This percentage represents the portion of incoming blood from the lungs that the heart can move back out to the body on each stroke. In other words, whatever amount the heart brings in from the lungs, it can pump out XX% to the body on each stroke. Normal hearts never hit 100%. If I remember correctly (somebody correct me if I mis-quote this one), an average EF is in the range of 55% to 70% for a healthy heart. Individual results above or below this range are cause for further evaluation. Not being an expert, I cannot tell you what it means if the patient's EF is higher or lower, but another web search might help. I do know that in cases of congestive heart failure (CHF), the patient's EF is typically much lower and in cases of aortic stenosis (restricted valve opening), it is often somewhat higher.

I hope my quick synopsis helps in general. Perhaps a more careful reading of your son's most recent echo report might help ensure that you have all of the measurements in mind. Check it out, then post some more data and maybe we can get someone who can help evaluate the results.

 

[big_L]

I would second Steve's recommendation. Get the echo report and spend some time with it. You can google and find a lot of help on the details, such as this.