DEAR DR. DONOHUE: After my last test with my cardiologist, he stated that I have aortic valve stenosis. Will you explain what he meant by this? – W.S.

ANSWER: Heart valves keep blood flowing in the right direction through the heart, from chamber to chamber, and then out of it. The aortic valve keeps blood from leaking back into the heart after it has been pumped out into the aorta. Aortic stenosis is a narrowed aortic valve.

Upon examining you, your doctor might have heard the typical heart murmur produced by aortic stenosis.

Valve narrowing can be a consequence of a slight difference in the valve’s construction, there from birth, or it can result from rheumatic fever or from calcification of the valve that comes with aging. The significance of aortic stenosis depends on how greatly the valve is narrowed. A significantly narrowed valve puts a burden on the heart in its pumping action. The heart enlarges. There comes a point, however, when enlargement cannot keep up with the stress imposed by the narrowed valve, and symptoms arise. Chest pain when physically active, fainting episodes and breathlessness are three signs that the valve is critically narrow and the heart is overworked.

The valve’s dimensions can be measured on an ultrasound examination.

Your doctor might have made a passing remark about your aortic stenosis, one that was meant to imply the valve is not a serious problem. Valve narrowing can progress slowly. If you have no symptoms, you might never have any. When symptoms develop, the treatment is surgical valve replacement. That might never enter the picture for you.

Heart valve problems are discussed in the booklet on that topic. Readers can order a copy by writing: Dr. Donohue – No. 105, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: My wife and I recently requested that our doctor switch both of us from Lipitor to the generic brand simvastatin (Zocor). By doing so, we save $40 a month. We both take it. When we picked up the simvastatin tablets, we noticed that the dose was 40 mg, whereas our Lipitor tablets were 10 mg. We checked with the doctor, and he said the dose was fine. Is it OK to continue with this dose of simvastatin? – R.L.

ANSWER: The six statin drugs (Lipitor, Lescol, Crestor, Pravachol, Zocor and Mevacor) are the most powerful cholesterol-lowering drugs available. Which is the best is a tough call. They all work well. The criterion for making a choice is finding the drug that lowers cholesterol to the desired level and is the cheapest.

Statin drugs stop the liver’s production of cholesterol, the source of most of our blood cholesterol.

The suggested daily dose for Lipitor (atorvastatin) is 10 mg to 20 mg, but the uppermost dose can be 80 mg. The suggested daily dose for simvastatin (Zocor) is 20 mg to 40 mg, about twice the dose of Lipitor. Your current dose falls within that range.

You’ll know if you’re getting too much or too little by your next blood cholesterol check and by any symptoms you might develop. The 40 mg dose isn’t unreasonable and is safe.

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 32853-6475. Readers may also order health newsletters from www.rbmamall.com