DEAR DR. DONOHUE: During my yearly exam, my doctor heard a noise in my left neck artery. He sent me to have a scan, which showed I have a 75 percent blockage in that artery. He says I should have surgery. I have heard that this is very risky surgery and I could end up with a stroke or worse. What’s your opinion? What can I do other than surgery to prevent a stroke? – X.B.

ANSWER: Strokes result from interruption of blood flow to a part of the brain. An obstruction in the right or left carotid artery – the two large neck arteries that supply the brain with blood – is one cause for a stroke, and it is a major cause. The obstruction in those neck arteries arises for the same reasons that obstructions in heart arteries arise – high blood cholesterol, smoking, inactivity, high blood pressure, diabetes, genes and unknown factors.

A 75 percent obstruction is a very significant obstruction and puts you at high risk for having a stroke. Reaming out the obstruction – a carotid endarterectomy – or replacing the site of obstruction with a graft takes you off the list of people likely to have a stroke. The surgery does have risks. It can cause a stroke or even death, but the risk is small compared with the risk of doing nothing.

Blocked heart arteries can sometimes be unplugged by dilating them with a balloon-tipped catheter, and that procedure is under evaluation for blocked carotid arteries.

If I faced your dilemma, I would choose surgery.

Alternatives to surgery include taking medicines that lower cholesterol, just as people with heart artery blockages do. Blood pressure control is important. Lifestyle changes – exercise, weight loss, not smoking, and moderating salt use – are other elements that can slow the progression of an obstruction.

More than three-quarters of a million North Americans will suffer a stroke this year. Readers who would like more information on strokes, their treatment and prevention can order the stroke booklet by writing: Dr. Donohue – No. 902, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.50 U.S./$6.50 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: What about alcohol and erectile dysfunction? And why are nitrate medications a problem for people with ED? What are they, and who takes them? – Anon.

ANSWER: On a single occasion, too much alcohol can increase libido but often interferes with performance. On a chronic basis, immoderate alcohol use definitely leads to erectile dysfunction, which might not be reversible when alcohol is discontinued.

The principal use for nitrate medicines is for angina, the chest pain due to partially blocked heart arteries. The pain comes on when a person is active. Nitrates can expand those arteries to allow more blood to get to heart muscle. Nitroglycerin (which comes as a tablet to put under the tongue, an ointment for the skin, or a skin patch), Isordil, Imdur and Sorbitrate are some brand names. These drugs are not contraindicated for people with ED.

However, they cannot be used with the ED drugs Viagra, Cialis and Levitra. Nitrates combined with these drugs can drop blood pressure to dangerously low levels.

There is another class of drugs, alpha blockers, some of which have to be used with caution with the above ED drugs.

DEAR DR. DONOHUE: Please explain what a mugger scan of the heart is and what the resulting values of ejection fraction mean. About two years ago, when I had congestive heart failure, I had a mugger scan that showed an ejection fraction of 25. Now it is 57. – G.S.

ANSWER: A MUGA (multiple gated acquisition) scan is a special kind of heart scan that provides pictures of the heart and gives the ejection fraction, the amount of blood pumped with each heartbeat. A normal ejection fraction is 68. The lower limit of normal is 50. Your current value is fine. You have made a remarkable recovery.

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.

Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.