Coronary Artery Disease

Coronary artery disease (CAD) is sometimes called coronary heart disease, ischemic heart disease, or atherosclerotic cardiovascular disease.   Often, when people refer to the general term “heart disease,” they are talking about CAD as it is the most common. CAD is the leading cause of death among men and women in the United States.  However, we now have better ways to allow people with CAD to live healthy lives and decrease the risk of heart attack through lifestyle changes, medications, and some interventional procedures.  CAD cannot be cured but it often can be effectively treated.

CAD is a condition where plaque, which is made up of fat, cholesterol, calcium, and other substances in the blood, builds up inside the coronary arteries.  This plaque build-up is called atherosclerosis. Plaque can grow large enough to reduce the flow of blood through an artery. Angina occurs when the heart cannot get enough oxygen-rich blood, although blockages do not always lead to symptoms. While atherosclerosis occurs over many years, serious damage to heart muscle supplied by arteries with plaque can occur in minutes, sometimes with no warning.  A piece of plaque can break off at any time and block a narrowed artery, causing a heart attack.

The inner, central and open part of the artery is referred to as a lumen.  Arteries that feed blood to the heart are called coronary arteries. At a certain point the heart muscle is not getting adequate blood or oxygen, especially when it has to work harder with exertion. This can lead to symptoms like chest pain (angina), or when severe, a heart attack, where permanent heart damage can occur.

While plaque can gradually grow large enough to totally block blood flow through an artery, more frequently, a plaque may suddenly break, causing a blood clot to form that blocks a coronary artery.  Most heart attacks occur when this blood clot suddenly cuts off part of the heart’s blood supply.  How much damage depends on if the body can open up the blockage or get rid of the clot, and how much heart muscle is supplied by the blocked coronary artery.  A heart attack can result in sudden cardiac death due to sudden arrhythmias caused by dying heart muscle cells. While heart attacks are more common in older individuals, they can occur in relatively young people in their 40′s and 50′s even with no prior warning signs.  It is important to assess the risk of CAD based on risk-factors like hypercholesterolemia, hypertension, family history of CAD, smoking, and diabetes.

When heart muscle (myocardium) does not get adequate blood supply or oxygen, if suffers from myocardial ischemia.  A heart attack not only occurs if the heart muscle has all blood supply totally cut off by a blood clot, but also if severe myocardial ischemia lasts too long.  Either way, a heart attack is called myocardial infarction. Over time, CAD can weaken the heart muscle with recurrent myocardial ischemia and contribute to heart failure or arrhythmias.

Symptoms of CAD

While usually referred to as a “pain” in the chest, most commonly, people describe the feeling as a pressure or tightness in the chest, as if a weight was put on the chest. When a coronary artery is 60 – 70 % blocked and stable, angina is usually brought on by physical activity or stress, or emotional stress which leads to myocardial ischemia.  When stable, it typically resolves within minutes after the stressful activity is stopped.  Often medications such as nitroglycerin are required to control symptoms. People can have “angina” that spreads to other areas, such as the neck, back or arms or even have their discomfort starting in these areas.  Angina tends to be more common in men.  Some people have myocardial ischemia but no angina that can be picked up on stress tests.

Some people have a sensation of shortness of breath rather than chest discomfort. However, shortness of breath can occur alongside angina, especially if the myocardial ischemia is causing enough heart muscle to not perform adequately.  Often people have extreme fatigue with exertion.

If myocardial ischemia leads to arrhythmias, sometimes just due to occasional extra heart beats coming from the heart muscle, people can experience palpitations.  They might also have general weakness or lightheadedness due to arrhythmias or the heart not pumping adequately.

Classically, signs and symptoms of a heart attack include more severe pressure in the chest and/or neck, shoulder or arm, sometimes accompanied by shortness of breath, sweating, nausea or lightheadedness.  Women are more likely than men to experience less typical signs and symptoms such as jaw, upper abdominal or back discomfort, or nausea and lightheadedness, even without chest discomfort.  Some heart attacks can occur without any obvious signs or symptoms.  If you think you’re having a heart attack, call 911 immediately.

Risk Factors for CAD

Abnormal cholesterol; particularly high levels of low density cholesterol, small and dense LDL particles even if the LDL level is normal, and low levels of high density cholesterol.

Hypertension or high blood pressure which can contribute to hardening and thickening of your arteries.

Diabetes

Smoking.  Nicotine constricts blood vessels and carbon monoxide can damage their inner lining, making them more susceptible to atherosclerosis.  The chance of heart attack in women who smoke 20 cigarettes or more a day is six times that of women who’ve never smoked.  For men who smoke, the risk is triple that of nonsmokers.

Family history of CAD is associated with a higher risk, especially if a close relative developed it at an early age.  Your risk is highest if your father or brother was diagnosed with CAD before 55 years or your mother or a sister developed if before age 65.

Obesity

Physical inactivity

Advancing age

Male sex

Non-classic and emerging risk factors for CAD

Chronic inflammation

HIV

History of radiation therapy to the chest, as is used for certain types of cancer.

High stress.  Unrelieved stress in your life may directly contribute to damaging your arteries.

Sleep apnea. Drops in blood oxygen levels occurring during sleep increase blood pressure and strain the cardiovascular system, possibly leading to CAD.

Elevated Lipoprotein

Diagnosing CAD

To start, a physician needs to get a history from a patient and perform a physical exam, but specific testing helps establish the diagnosis or determining the best treatment for a patient with a known diagnosis of CAD.  Several of the routine tests include:

ECG (EKG or electrocardiogram), a 5 -minute test that can reveal evidence of a prior heart attack, myocardial ischemia, or rhythm abnormalities.

Echocardiogram, an ultrasound of the heart that might show signs of a prior heart attack.

Stress testing, including stress echo and myocardial perfusion imaging stress testing. These tests are an indirect way of determining if adequate blood flow is getting to the heart muscle during physical activity or stress.  If signs of myocardial ischemia are seen, it suggests blockages in the coronary arteries.

Coronary angiogram, an invasive procedure requiring plastic catheters or tubes (cardiac catheterization), be put through the skin into an artery that leads to the heart.  Under real-time x-ray video, contrast dye is injected through the catheters and into coronary arteries to allow the arteries to be visualized.  This can reveal if blockages are present and how severe they are, and can allow interventions such as angioplasty or stents be performed to open up blockages.  This is considered the “gold standard” test to determine severity of CAD although sometimes requires non-invasive tests as well to determine the best therapeutic options.  Now, it is mostly used in the setting of heart attacks, unstable or very severe symptoms, or in patients whose symptoms cannot be adequately be controlled with medications and lifestyle changes.

Treating CAD

Heart-healthy lifestyle, including quitting smoking, eating a heart-healthy diet, exercising regularly, losing excess weight, and reducing stress. This is arguably just as important as medications and high-technology interventions.

Statins and optimizing cholesterol levels.  Decreasing low-density lipoprotein (LDL) decreases the primary substance that contributes to plaque buildup in the arteries.  Statins seem to have additional healing powers and beneficial effects on arteries as well which is why they are usually used, even in patients with normal cholesterol levels.

Treating high blood pressure.  Some type of drugs used for hypertension such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers might help prevent progression of CAD and reduce the risk of future heart attacks in those whom have already had one.

Aspirin and other anti-platelet blood thinners.  As heart attacks are due to platelets clumping in a coronary artery, thinning the blood or making platelets weaker reduces the risk of heart attack.  However, as it increases the risk of bleeding, if one has a bleeding disorder or high risk of bleeding, aspirin might not be appropriate.  Always discuss the pros and cons of taking aspirin with your doctor.  Other anti-platelet blood thinners are sometimes used in addition to aspirin.

Anti-anginal medications, like beta-blockers slow your heart rate and decreases your heart’s demand for oxygen.  If you’ve had a heart attack, beta blockers reduce the risk of future attacks. Nitroglycerin tablets, sprays and patches can control angina by opening up coronary arteries and reducing the pressure inside the heart.  Calcium channel blockers relax the muscles of the coronary arteries and open the vessels increasing blood flow to the heart.  They also reduce high blood pressure.

Percutaneous coronary interventions can be lifesaving if done early in the course of a heart attack, or at least reduce the amount of permanent damage to heart muscle and potential complications.  An interventional cardiologists inserts a long, thin tube up through an artery in the leg or arm and up into the coronary artery with the blockage.  A skinny, very flexible wire is threaded up through the catheter and coronary artery and through the blockage or narrowed area.  A balloon is threaded over the wire, often nowadays with a stent on it and the balloon is inflated, compressing the plaque against the artery wall and opening up the narrowing. Stents help prop and keep the artery open and often have a medication that is slowly released to help keep the artery open. In stable patients, if they continue to have symptoms from CAD not adequately controlled by medications, then a PCI might help them feel better.  While an important intervention for patients having a heart attack, PCI generally does not prevent heart attacks in stable patients.

Coronary artery bypass surgery is surgical procedure that has existed for over four decades where a surgeon uses a blood vessel from another part of the body to bypass blockages in the coronary arteries. Because this requires open-heart surgery, it is usually reserved for cases with multiple narrowed coronary arteries with other high-risk features not amenable to PCI.

While healthy lifestyle changes are the foundation of treating CAD, regular medical checkups to make sure the disease is stable and medications are appropriate, are critically important.  In addition, some of the main risk factors for CAD — high cholesterol, high blood pressure and diabetes — are non-symptomatic in the early stages.  Early detection and treatment can set a patient up for a lifetime of optimal heart health.

Preventing CAD

The same lifestyle habits that can help treat coronary artery disease can also help prevent it from developing at all. Leading a healthy lifestyle can help keep your arteries open and clear of plaque. Primary prevention is the term used to avoid CAD in those with no history of it and secondary prevention is when someone has known CAD who is trying to prevent its complications such as angina and heart attack.

Whether for primary or secondary prevention, to improve your heart health you can:

Eat a diet rich in fruits, vegetables, whole grains, and fish, and avoid saturated fats and processed foods.  Make sure the predominant fat used is from monounsaturated fats.

Stay physically active

Maintain a healthy weight

Reduce and manage stress

Quit smoking

Control conditions such as high blood pressure, high cholesterol, and diabetes


Charles A. Shoultz, Jr., M.D., F.A.C.C.   •   Charles A. Shoultz, III, M.D., F.A.C.C.   •   Rodney A. Brown, M.D., F.A.C.C.
William R. Pitts, M.D., F.A.C.C.   •   Donald S. (Buck) Cross, M.D., F.A.C.C. • Andrew K. Day, M.D., F.A.C.C.
Sherwin F. Attai, M.D., F.A.C.C.   •   Shawn J. Skeen, M.D. F.A.C.C.   •   Harvey R. Chen, M.D. F.A.C.C.
Adam M. Falcone, M.D., F.A.C.C.   •   Brian C. Barnett, M.D., F.A.C.C.

Diplomates, American Board of Internal Medicine,
Cardiovascular Disease, Interventional Cardiology, Clinical Cardiac Electrophysiology