HEALTH MATTERS: Stents not guarantee against future coronary events

• Dr. Joshua Wynne

Dr. Joshua Wynne

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Q. I had a stent inserted in an artery in my heart some time ago because I was having frequent chest discomfort with exertion. But last week, I had a heart attack! Isn’t the stent supposed to prevent heart attacks?

A. It sounds like you had a stent inserted for the right reason — frequent chest discomfort that had not responded to medication that was interfering with your lifestyle. That’s the most common reason we insert a stent — to improve symptoms caused by coronary artery blockages. In some cases, we use stents while a person is having a heart attack to open up the artery, improve blood flow down the artery, and thus increase patient survival after a heart attack. But in most cases, stents are used primarily for improving symptoms.

Why would someone have a heart attack after a stent was inserted? Let’s start with some background information. Stents are like tiny Slinkys that help prop open diseased arteries. They compress the fatty deposits against the side of the artery and help to keep the center passageway open.

However, because they are made of metal and are foreign to the body, they can cause blood clots to form on them. We use medicines such as aspirin and clopidogrel (Plavix) after a stent is inserted to reduce that tendency, but clots occur in about one in every 200 or so people with stents. Thus, the first reason you may have had a heart attack is that a clot formed in the stent.

To prevent this from occurring, it is important for all patients with stents to take their medicines exactly as prescribed.

A more common reason for having a heart attack after a stent is that another part of the artery developed a problem and caused the heart attack. A stent typically covers less than an inch of the coronary artery, so a great length of the diseased artery is left unprotected by the stent and is prone to narrowing and thus heart attacks — despite a perfectly functioning stent.

The best prevention for this is to take cholesterol-lowering medications, blood pressure pills and other medicines designed to limit the amount of the cholesterol deposit in the artery and the propensity for the artery to close off (thus causing a heart attack). The bottom line is that stents are not a guarantee against future coronary events — heart attacks included — and are most useful for improving symptoms.

In general, they do not improve survival, but they do improve quality of life, exercise capacity and a sense of well-being.

By the way, the same is true in general of coronary artery bypass surgery or CABG. We know know that in some patients survival also is improved. However, for most patients, CABG is used to improve symptoms, exercise ability and lifestyle.

In Canada, where stents and CABG are used much less frequently, the survival rate of Canadians with coronary artery disease is quite similar to the survival rate in the United States. Americans, however, have better relief of symptoms than Canadians because of the use of stents and surgery.

Wynne is vice president for health affairs at UND, dean of the School of Medicine and Health Sciences, and a professor of medicine. He is a cardiologist by training.

Submit a question to Health Matters at healthmatters@med.und.edu or Health Matters, 501 North Columbia Road, Stop 9037, Grand Forks, ND 58202-9037. Remember, no personal details, please.

The content of this column is for informational purposes only and does not substitute for professional medical advice or care. The information provided herein should not be used for diagnosing or treating a health problem or disease. If you have or suspect you may have a health problem, you should consult your health care provider. Never disregard professional medical advice or delay in seeking it because of something you have read in this column

Tags: life, health, stents, heart