Posts for: November, 2018
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.”
I know that this is a pretty broad question. Therefore, I would like to start by setting my boundaries. First, I would like to take the question from a big picture perspective because that approach helps to understand most of the recommended preventive efforts and treatments. Second, I want to be clear about the meaning of coronary artery disease. Three arteries ring the top of the heart like a crown, giving them the designation coronary, from corona. Any illness that affects these arteries is reasonably called coronary artery disease. But, let’s not ignore the elephant in the room. One disease will affect ⅓ to ½ of us in our lifetime, loves the arteries of the heart and, most importantly, causes heart attacks. The disease is atherosclerosis, a corrosive scarring of the arteries, and almost any time someone says coronary artery disease, that is what they mean.
Atherosclerosis is a disease in the sense that it causes illness and suffering. However, the source of the problem is, to a great extent, in how we are designed to process and store what we eat and maintain our arteries. As most of us make the morning navigation to work, we mull over thoughts of success that center on peace, serenity and financial security. Mother nature sees things from a different perspective than you and I. From the biological perspective, success is navigating our hostile world long enough to reproduce. That is the target of our design and the goal of the genes that help to make us who and what we are. The genes that have made us such a rousing success developed under much different circumstances than we face today. In a hostile world, with scarcely enough to eat, full of predators, large enough to eat us and too small to be seen, those genes carried primitive people through their twenties and thirties, long enough to be fruitful and multiply.
Generally speaking, people are made to survive frequent hardship, long walks looking for food and long times without it. Weather was to be endured, abundance enjoyed and water kept in convenient reach. These were the challenges to be overcome for success and we are well equipped. We have long legs, can eat almost anything and store energy with great efficiency. However, our most important advantage is not physical.
We have the ability to learn, individually and collectively. We can make tools, build houses and, most importantly, write everything down. This advantage brings plentiful food, treatment for infections and longer lives. Under these conditions, our biological design for self-preservation misfires in many forms of cardiovascular disease such as high blood pressure and coronary artery disease. In essence, our heart and arteries are designed to maintain themselves under a set of difficult conditions and last a lifetime. With all of the success born of cumulative learning, we have moved outside of the conditions that shaped us and changed the duration of a lifetime.
Modern society lets us survive long enough to suffer from atherosclerosis and modern technology lets us see it. At any given time, more than 15 million people in the US have symptomatic atherosclerosis. It affects the heart most famously, but can also cause stroke, loss of limb, damaged kidneys and dysfunctional intestines. Of the 1 million people who will have a heart attack this year, almost all are over 40, an age seen by a lucky few of our primitive ancestors.
Atherosclerosis is very much affected by the body’s energy metabolism. It strolls along happily with obesity and inactivity. Obese and inactive adolescent children may already have arteries that misbehave. Their arteries may not be diseased at that young age, but measurable misbehavior is believed to be one of the first steps toward disease. By the age of thirty, some people may have an abnormal appearance of the arteries on an angiogram. Most heart attacks occur much later in life, meaning that this disease starts early and may be present for a very long time before it starts to cause problems.
Atherosclerosis can remain silent for so long because it is alive. Unlike the debris in a clogged drainpipe, atherosclerosis is in constant negotiation with the walls of arteries, forcing them to adapt to its presence. Baudelaire said that the “finest trick of the devil is to persuade you that he does not exist”. Atherosclerosis has mastered this trick as well. Arteries accommodate disease in their walls by enlarging so that blood flows freely. Each step that may help atherosclerosis along does not exact immediate restitution, but lays claim much later, when the arteries can no longer accommodate. Fortunately for us, atherosclerosis is the rarest of all biological cats. By addressing the root cause of disease, we can put it back in the bag… at least part way.
The processes, actions and events leading up to a heart attack are partly determined by our inborn programming and partly by the life that we lead. The almost universal coexistence of plentiful food and heart attack lends credence to the misunderstanding that atherosclerosis is simply a penalty for each moment spent enjoying a cup of coffee and a donut. The truth is a bit more complicated. We each live within a design that dictates how we store energy from food, distribute salt and water, fight infection and function physically. Our design was shaped under different conditions from those that we presently encounter. As a result, many of us may encounter difficulty as we age because the lifestyle that has become normal combines with our design to steer a course that will end in decay of our arteries. For most of us, the inherited parts of our design that predispose to atherosclerosis and heart attack are not genetic errors. They are built-in safeguards for times of need. In a different setting, of environment or of food availability, these tendencies may be advantages for survival. In times of plenty, they are not.
Preventing or treating atherosclerosis requires realignment of modern lifestyle with our design. Alignment with design refers to all of us in a general sense as well as each of us specifically. We do not all share the same inheritance. Therefore, the prescription to align with our design will vary from person to person.
More on coronary artery disease can be found in the educational booklets for CAD and Heart Attack here.