Ask the Doctor: Valves Will Need to Be Replaced
DEAR DR. DONOHUE: I am 71 and have had aortic stenosis for 10 years.
I have echocardiograms every year.
I do not take medicines.
1. What echocardiogram measurements evaluate this condition?
2. What changes require valve replacement?
3. What amount of change is a normal rate of progression?
4. At what measurement is the problem considered dangerous?
5. Does a heart attack occur?
6. Is valve replacement similar to bypass surgery?
7. What valves are better, and what is their lifespan?
- P.P.
ANSWER: Two weeks ago, I answered a question on leaking aortic valves.
Your problem involves the same valve but a different process.
Your valve is closing up - narrowing, stenosing.
The heart has to beat with more force to get blood through the narrowed valve.
The heart enlarges to produce enough pressure to accomplish that feat.
With the passage of time, enlargement can’t compensate, and the heart fails.
Death comes as a result of heart failure and not a heart attack.
Or it can come from abnormal heart rhythms (question 5).
Symptoms indicate the severity of the narrowing.
You have none. That’s a good sign.
Serious symptoms are chest pain (angina) when active, shortness of breath on exertion and fainting spells.
The echocardiogram at that stage shows an area of the aortic valve less than 1 centimeter squared.
A normal aortic valve has an area of 3 to 4 square centimeters (questions 1, 2 and 4).
That’s the time for valve replacement (question 2).
On average, a stenotic valve narrows by 0.1 centimeter squared every year (question 3).
Valve replacement is similar to bypass surgery only in the approach to the heart.
In bypass surgery, clogged heart arteries are replaced with grafts to re-establish blood flow to the heart muscle.
The surgery takes place on the heart’s surface.
In valve surgery, the heart is opened to expose the valve.
The narrowed valve is removed and a new one is installed (question 6).
Two kinds of heart valves are used - biologic or mechanical. Biologic valves are ones taken from pigs, cows or human cadavers.
Mechanical valves are made from metallic alloys and plastics.
Mechanical valves last longer, but they encourage clot formation, so they require anticoagulation (blood thinners).
Biologic valves don’t require anticoagulation.
Around 50% of them have to be replaced in 15 years, but newer materials are extending their life.
These valves are used in older people (question 7).
Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853.
