What is Coronary Stents?
Coronary stents are metal tubes that are placed into coronary arteries, which might be narrowed due to a disease called atherosclerosis. This process of placement, often referred to as percutaneous coronary intervention (PCI) or coronary angioplasty with stent placement, helps restore adequate blood flow. The invention of coronary stents happened in the 1980s and since then they have seen improvements in shape, structure, and material. Before stents, the standard procedure was a balloon angioplasty. This involved inserting an inflatable balloon into the arteries to push against and compress the blockage, restoring blood flow. This method had major downfalls including potential recoil of the artery, splitting of the coronary artery, blood clots, and narrowed arteries due to an overgrowth of tissue. The design of stents, which are expandable metal mesh structures, helped to avoid these problems.
There are different types of coronary stents: Bare Metal Stents (BMS), Drug-Eluting Stents (DES), Bioresorbable Scaffold System (BRS), and Drug-Eluting Balloons (DEB).
DES stents consist of three parts: a metal base, a medication, and a carrier vehicle. Common metals used are stainless steel or cobalt-chromium, providing long-term stability against artery narrowing. The medication part of the stent is designed to block overgrowth of tissue in the stented artery. These drugs interfere with the building blocks of cells, blocking the increase of unnecessary tissue.
Another component of the DES is a special coating that allows the drug to be released slowly over time. This coating is made up of biodegradable substances that eventually break down into water and carbon dioxide. The drug release is carried out by diffusion through small holes in the coating.
On the other hand, DEB only has a drug coating without any metal structure while BRS dissolves completely a few months after placement. There are also special stents designed for specific situations such as when the disease affects a fork in the artery or if the coronary artery has been punctured.
What Causes Coronary Stents?
Atherosclerosis is a medical condition where plaques, or build-ups, form in the arteries. This condition is the root cause of coronary artery disease, which affects the heart. There are many known risks that can increase the chance of developing or advancing atherosclerosis. These risks are grouped into two categories: those you can change, and those you can’t.
You can change or control these risk factors:
- High cholesterol levels
- High blood pressure
- Diabetes
- Smoking cigarettes
- Not getting enough physical activity
- Being overweight or obese
On the other hand, you can’t change or control these risk factors:
- Age
- Sex
- Having a family history of early heart disease
Risk Factors and Frequency for Coronary Stents
Coronary artery disease (CAD) is a prominent health issue influencing people globally and is the reason behind 20% of all deaths in the United States. The disease is caused by a condition called atherosclerosis, which results in the formation of plaque in the coronary arteries. However, pinpointing the precise frequency of atherosclerosis is tricky as it often shows no symptoms until it becomes severe. Atherosclerosis usually starts in childhood and gradually worsens over time. More severe cases typically surface in those who are in their 50s or 60s. In the United States alone, around 14 million people are affected by CAD and experience complications, heart failure being the most significant post-a heart attack.
Approximately 1.5 million people in the United States endure an acute myocardial infarction (AMI, or heart attack), annually, and one-third of these cases result in fatalities. In 2009, about 785,000 Americans experienced their first heart attack, while 470,000 faced a recurring heart attack. An estimated 195,000 “silent” heart attacks occur annually, equaling a heart attack occurring in an American every 34 seconds.
In developed countries, the rate of heart attacks is similar to that of the US. In contrast, the risk is lower when following the Mediterranean diet, like in France, due to its health benefits, a concept called the “French paradox.” However, the prevalence of CAD is increasing in African countries due to urbanization and adopting western lifestyles, despite being previously rare. Race also impacts incidence rates; black populations have higher rates due to health conditions like hypertension and obesity. Likewise, men are more prone to CAD prior to menopause, but post-menopause, occurrence rates in women equal that of men.
Signs and Symptoms of Coronary Stents
Coronary atherosclerosis is a medical condition that often causes heart disease but typically goes unnoticed for a long time. It starts early in life but is usually silent and doesn’t produce any symptoms until it becomes serious. Symptoms only start to show when 50% to 70% of the heart’s blood flow gets affected due to growing unhealthy fat deposits in the arteries. We have two types of conditions here: ‘stable coronary artery disease’, which generally shows symptoms of chest pain during physical exertion and ‘acute myocardial infarction’ where rupture of these fat deposits leads to symptoms similar to a heart attack.
People experiencing coronary artery disease might have the following symptoms:
- Stable chest pain (stable angina)
- Unpredictable chest pain (Prinzmetal’s angina)
- Heart attack symptoms (Acute myocardial infarction or AMI)
- Sudden unexpected death due to heart problems (Sudden cardiac death)
- Chronic heart disease caused by insufficient blood supply (Chronic ischemic cardiomyopathy)
- Heart’s inability to pump sufficient blood (Congestive heart failure or CHF)
The most common complaint is chest pain, which may feel like a dull, squeezing or pressure-like ache in the chest area, often radiating to the left arm, neck, or jaw. Associated symptoms may include shortness of breath and increased sweating. Pain due to a heart attack usually occurs at rest and only partially responds to medication like nitrates.
During a physical examination, a patient with a heart attack may present with the following:
- Sweating excessively
- Breathing rapidly or difficulty breathing
- Crackling sounds in the lungs due to fluid build-up, difficulty breathing while lying flat, and disturbed sleep caused by difficulty breathing
- Low blood pressure or shock due to negatively affected heart function
- Abnormal heart sound due to faulty heart valves
- Skin abnormalities due to underlying cholesterol problems
- Potential heart rhythm abnormalities
Fast heart rate is common, while slow heart rate can occur if the heart’s natural pacemaker gets affected. Disruptions of normal heart rhythms can occur due to the negative effect of reduced oxygen and energy supply to the heart. These disruptions can lead to irregular heartbeats and are associated with a higher risk of sudden death due to a heart attack.
Testing for Coronary Stents
For people suspected of having coronary artery disease, which is a condition that sees your heart’s major blood vessels get damaged or diseased, your doctor might suggest certain tests. Here’s a little about what they might order:
A full blood test, also known as a Complete Blood Count (CBC). This is helpful to see if you’re anemic – a condition where your blood doesn’t have enough healthy red blood cells or hemoglobin. The symptoms of anemia, like chest pain and shortness of breath, can be similar to coronary artery disease because both involve decreased oxygen supplied to the body.
A Thyroid Function Test, which examines how your thyroid is working. Hyperthyroidism (where your thyroid is overactive) can also lead to symptoms like heart palpitations, heart rhythm problems, or chest pain.
A Fasting Lipid Profile. High levels of certain kinds of fats – triglycerides, total cholesterol, and Low-Density Lipoproteins (LDL) – in your blood can contribute to heart disease.
An Electrocardiogram (EKG) that records the electrical signal from your heart to check for different heart conditions. In conditions like a heart attack, it can show changes in your heart’s activity.
In addition to these, your doctor might also check for specific proteins that your heart releases when it is damaged (like during a heart attack). These are called Cardiac enzymes, and include Creatine Kinase, Troponin and Lactate Dehydrogenase.
Your doctor might order an Echocardiogram. This test uses sound waves to produce images of your heart’s structure and check for abnormalities.
Sometimes, a stress test (like an Exercise Tolerance Test or Nuclear Stress Imaging) might be recommended to see how your heart responds to exertion.
Depending on your case, the doctor might suggest a Coronary Angiography, a test that uses dye and special X-rays to show the insides of your coronary arteries.
Other tests like the Intravascular Ultrasound or Fractional Flow Reserve might also be suggested. These tests can help the doctor understand more about plaque buildup in the heart’s arteries and blood flow in these arteries. This can be crucial to decide the best course of treatment for your condition.
Treatment Options for Coronary Stents
Coronary angioplasty is a procedure that opens up blocked or narrow arteries in the heart. It’s often used with a stent, which is a tiny tube that keeps the artery open. This procedure is used when patients have certain heart conditions, including:
* Non–ST-elevation myocardial infarction or acute coronary syndrome
* Acute ST-elevation MI (STEMI)
* Stable angina that doesn’t respond to standard treatment
* Symptoms similar to angina, such as shortness of breath, irregular heartbeats, dizziness, or fainting
* Symptoms in people with evidence of medium to large-sized area of moderate to severe decreased blood flow on tests
Coronary stents were developed to overcome issues with another treatment, balloon angioplasty, which was revolutionary back in 1977. While it was a major step forward because it allowed doctors to avoid open chest surgery, it had downsides such as the possibility of a vessel suddenly closing soon after the procedure. Because of this, they eventually developed the first type of coronary stent called a bare-metal stent in 1986 which solved some of these problems.
Bare-metal stents greatly reduced the chances of a vessel suddenly closing, and also got rid of concerns around the vessel potentially shrinking back after the procedure. However, long-term follow-ups found that many people who received these stents dealt with restenosis, which is when a previously opened artery narrows again.
In the early 2000s, a newer form of stent called a drug-eluting stent became popular. This type of stent not only keeps the artery open but also releases medication to stop restenosis. While this was a major improvement, it did have a new downside: a higher chance of early stent thrombosis, which is when a clot forms in the stent. This issue was largely addressed by using blood-thinning medications after surgery.
Currently, new-generation drug-eluting stents are in use, which are made from better materials and feature improvements like thinner struts. Thinner struts result in less damage to the vessel during the implantation and a reduced chance of restenosis. Newer stents also use different materials to release medication without the need for the polymer coating seen in earlier drug-eluting stents. These newer stents often use medication known as sirolimus or its alternatives due to better results compared to previous drugs.
What else can Coronary Stents be?
Chest discomfort is often the main sign of coronary artery disease, a condition where the heart’s arteries become narrowed or blocked. However, it’s important to remember that other health issues can also cause similar chest pain. These may include:
- Unstable angina (a type of chest pain that occurs when blood flow to the heart is reduced)
- Heart attack (there are two types – one involves specific changes in the heart rhythm, the other does not)
- A tearing in the aorta, which is a main artery in your body (this is known as ‘aortic dissection’)
- Takotsubo cardiomyopathy, also called ‘broken heart syndrome’
- Vasculitis, or inflammation of blood vessels (in children, Kawasaki disease is a type)
- Pericarditis, when there’s inflammation around the heart
- Myocarditis, or inflammation of the heart muscle
- Gastroesophageal reflux disease (GERD), a chronic condition where stomach acid flows back into your esophagus
- Pleuritis, inflammation of tissues that line the lungs and chest cavity
- Costochondritis, inflammation of the cartilage in the rib cage
- Pulmonary embolism, a blockage in one of the pulmonary arteries in your lungs
So, if you experience chest pain, it’s very important to get medical help to determine the cause of the discomfort.
What to expect with Coronary Stents
Coronary artery disease (CAD) remains the leading cause of death for both men and women worldwide. Every year in the United States, approximately 1.5 million Americans experience a severe heart attack, referred to as an AMI (Acute Myocardial Infarction), with about a third of them not surviving. Compared to the general population, those who do survive an AMI have a risk of death and heart-related complications ranging from 1.5 to 15 times higher.
Past data shows that of those surviving an AMI, 25% of men and 38% of women die within the first year. Within six years, 18% of men and 34% of women suffer a second heart attack. After an AMI, 22% of men and 46% of women are diagnosed with congestive heart failure, a condition often resulting from the damage to heart muscle.
The chances of a patient surviving an AMI depends on several factors, including:
– The presence of chest pain, referred to as angina,
– The fraction of blood that is pushed out of the heart during each contraction,
– The number, location, and extent of blockage in the coronary arteries,
– The status of any procedure undertaken to restore normal blood flow in the coronary arteries,
– Any abnormal heart rhythms,
– The patient’s adherence to their prescribed medication regimen, and
– The degree to which risk factors have been actively managed and controlled.
Possible Complications When Diagnosed with Coronary Stents
Coronary artery disease can lead to various complications. These include:
- Chest pain, which is also known known as angina pectoris
- Heart attacks, referred to medically as STEMI or NSTEMI
- Sudden cardiac death
- Heart failure due to damage to the heart muscle, called ischemic cardiomyopathy
- Irregular heartbeats or ventricular arrhythmias
- Fluid in the lungs, known as pulmonary edema, due to reduced heart functioning
- Mechanical problems after a heart attack such as ventricular free wall rupture which can lead to pressure buildup around the heart, a condition known as cardiac tamponade and a tear in the heart’s wall called interventricular septal rupture
Preventing Coronary Stents
Ischemic heart disease (IHD), a condition that affects the heart’s blood supply, is the leading cause of death worldwide. The most effective and important method to reduce the impact of IHD is through primary prevention which means taking steps before the disease develops.
Teaching people about a healthy lifestyle, good eating habits, and regular exercise has been proven to decrease the occurrence of IHD. Research also suggests that educational efforts centered around these topics may improve a person’s overall quality of life.
People diagnosed with IHD should be urged to strictly follow recommended medication routines and lifestyle changes to lessen the impact of risk factors affecting their heart health. Specifically, they should be encouraged to stop smoking, adopt a diet low in fat but rich in fruits and vegetables, and exercise on a regular basis. However, they should avoid pushing themselves too hard.
Patients are also advised to return to sexual activities four weeks after an acute heart attack, provided that they don’t experience chest pain during these activities. Joining support groups is another positive step, as these settings offer emotional support and practical tips from others living with the same condition. Recent research has shown that women often find most benefit in women-only groups, while men may prefer groups that include both genders.
