A short time ago, my email inbox contained a query from one of those online information sites. The question posed was, “Do stents prevent heart attack?” My initial impulse was to ignore the question altogether. It is too broad and too general for a simple answer. But then again, it is exactly what most people who are worried about coronary artery disease would like to know the answer to. What makes the question so difficult is that the answer is different, depending upon your perspective. This was my attempt at a reasonably complete, but concise answer.
The short answer
Yes. Without question, placement of a stent is an important part of the treatment options to prevent a heart attack. However, the complete answer is important.
The long answer
A stent is used to reduce narrowing, open an artery and improve blood flow to heart muscle. For everything, there is a season and for the stent, that season is when the heart is in need of rescue.
In order to review the idea of rescue as it pertains for stents, two major concepts require definition. They are angina and stability.
A narrowed artery to the heart may cause symptoms of chest discomfort during physical activity, with anger or other types of emotional stress. The particular type of chest discomfort (an uncomfortable uneasiness that doesn’t always hurt) is called angina pectoris, or just angina. The symptoms usually mean an artery is narrowed, but don’t tell you what the narrowing is made of.
When people experience angina, the discomfort may follow different patterns. The pattern of symptoms provides a clue as to what a narrowing that is causing the symptoms might be made of. Symptom patterns are generally condensed for descriptive purposes.
To the point of our discussion, some people have discomfort that they have noticed for at least two or more months. The discomfort is fairly consistent in its return with repetition of specific physical activity; for example walking up a hill or sweeping a room. This is called stable angina. “Stable” symptoms, or stable angina, is usually an indication that the narrowing responsible for the symptoms made of scar tissue. Scar tissue is relatively dormant and unlikely to change rapidly causing a heart attack.
On the other hand, some people experience symptoms that they have never felt before, that come on for no reason, or keep going away only to return slightly worse. These symptoms are said to be unstable. Unstable symptoms suggest that a blood clot is part of the narrowing responsible for symptoms. Blood clots are unpredictable, prone to grow very rapidly and are the cause of most heart attacks.
The important point is that the pattern of symptoms, stable or unstable, provides the indication as to whether or not a heart attack is threatened.
People who have stable symptoms are not facing imminent harm. Stable symptoms that are encountered only during time of great effort are easily managed. On the other hand, some people with stable symptoms find it difficult to shower and groom in the morning without stopping to rest. A person who is so limited, even after trying medication, may seek a rescue from his or her disease-imposed prison. By restoring blood flow to heart muscle and relieving symptoms, a stent may hold the key to that prison. This is very much a rescue and the proper use of a stent. However, the use of a stent for this purpose does not prevent a heart attack.
People who have unstable symptoms face the threat of a heart attack in the very near future. In fact, in some, the unstable symptoms are an indication of a heart attack that is under way. Since the heart is being damaged by a misbehaving artery, it is in need of rescue from harm. This is the type of rescue where a stent can stop or prevent a heart attack. Unstable symptoms fall into three major categories.
ST-segment Elevation Myocardial Infarction (STEMI) is a heart attack that is immediately apparent on an EKG. The diagnosis is recognized while damage is underway, triggering emergency treatment. Medicines that dissolve clot (Thrombolytic drugs) can be given very quickly. In hospitals with the capacity to perform emergency angioplasty, a balloon procedure and stent placement is preferred over thrombolytic drugs.
Non-ST-segment Elevation Myocardial Infarction (NSTEMI) is a heart attack that was not apparent on an EKG and recognized only after the fact by finding blood-test evidence of heart muscle damage in someone with unstable symptoms. Thrombolytic drugs are not useful, but rescue treatment with other medications, stents or sometimes surgery may be necessary to prevent additional damage and to speed healing.
Unstable Angina (USA) refers to unstable symptoms without evidence of a heart attack on the EKG or blood testing. The evidence of an unstable artery in need rescue is the discovery of a severely narrowed coronary artery that explains the unstable symptoms. In someone with unstable angina, placement of a stent, in addition to equally important medical therapy (cholesterol lowering, blood pressure control, diabetes control, aspirin and related drugs) unquestionably prevents heart attack.
For more information, stay tuned for “Heart Attack: The science and the story of what it is, why it happens and what to do about it.”