Coronary artery disease is the narrowing or blockage of the coronary arteries, usually caused by atherosclerosis. Atherosclerosis (sometimes called “hardening” or “clogging” of the arteries) is the buildup of cholesterol and fatty deposits (called plaques) on the inner walls of the arteries. These plaques can restrict blood flow to the heart muscle by physically clogging the artery or by causing abnormal artery tone and function.
Without an adequate blood supply, the heart becomes starved of oxygen and the vital nutrients it needs to work properly. This can cause chest pain, which is called angina. If blood supply to a portion of the heart muscle is cut off entirely, or if the energy demands of the heart become much greater than its blood supply, a heart attack (injury to the heart muscle) may occur.
Coronary artery disease starts when you are very young. Before your teen years, the blood vessel walls begin to show streaks of fat. As you get older, the fat builds up, causing slight injury to your blood vessel walls. Other substances traveling through your blood stream, such as inflammatory cells, cellular waste products, proteins and calcium begin to stick to the vessel walls. The fat and other substances combine to form a material called plaque.
Over time, the inside of the arteries develop plaques of different sizes. Many of the plaque deposits are soft on the inside with a hard fibrous “cap” covering the outside. If the hard surface cracks or tears, the soft, fatty inside is exposed. Platelets (disc-shaped particles in the blood that aid clotting) come to the area, and blood clots form around the plaque. The endothelium can also become irritated and fail to function properly, causing the muscular artery to squeeze at inappropriate times. This causes the artery to narrow even more.
Sometimes, the blood clot breaks apart, and blood supply is restored. In other cases, the blood clot (coronary thrombus) may suddenly block the blood supply to the heart muscle (coronary occlusion), causing one of three serious conditions, called acute coronary syndromes.
What Are Acute Coronary Syndromes?
Unstable angina: This may be a new symptom or a change from stable angina. The angina may occur more frequently, occur more easily at rest, feel more severe, or last longer. Although this can often be relieved with oral medications (such as nitroglycerin), it is unstable and may progress to a heart attack. Usually more intense medical treatment or a procedure are required to treat unstable angina.
Non-ST segment elevation myocardial infarction (NSTEMI): This type of heart attack, or MI, does not cause major changes on an electrocardiogram (ECG). However, chemical markers in the blood indicate that damage has occurred to the heart muscle. In NSTEMI, the blockage may be partial or temporary, so the extent of the damage is usually relatively small.
ST segment elevation myocardial infarction (STEMI): This type of heart attack, or MI, is caused by a sudden blockage in blood supply. It affects a large area of the heart muscle, and causes changes on the ECG as well as in blood levels of key chemical markers.
Although some people have symptoms that indicate they may soon develop an acute coronary syndrome, some may have no symptoms until something happens, and still others have no symptoms of the acute coronary syndrome at all.
All acute coronary syndromes require emergency evaluation and treatment.
How did I get coronary artery disease?
Heart disease is the leading cause of death among men and women in the United States. Risk factors for coronary artery disease are modifiable or non-modifiable and include the following:
- Male gender
- Advanced age, especially after the age of 65
- Family history of heart disease, especially if diagnosed before the age of 50
- Race- higher risk is associated with African Americans, Mexican Americans, American Indians, native Hawaiians and some Asian Americans
- Cigarette smoking and tobacco exposure
- High blood pressure (140/90 mmHg or higher)
- Uncontrolled diabetes (HbA1c>7.0)
- High blood cholesterol and high triglycerides (high LDL over 100 mg/dL or low HDL under 40 mg/dL)
- Physical inactivity
- Being overweight (BMI 25-29) or being obese (BMI higher than 30)
- Uncontrolled stress or anger
- Unhealthy diet
How Is Coronary Artery Disease Diagnosed?
Your cardiologist can make a diagnosis by talking to you about your symptoms, medical history and risk factors, as well as performing a physical exam and diagnostic tests. Symptoms may include the following:
- Chest pain, heaviness, tightness, pressure, aching, burning, numbness , fullness or squeezing
- Pain or discomfort in other areas of the upper body including the arms, left shoulder, back, neck, jaw or stomach
- Difficulty breathing or shortness of breath
- Sweating or “cold sweat”
- Fullness, indigestion, or choking feeling (may feel like “heartburn”)
- Nausea or vomiting
- Lightheadedness, dizziness, extreme weakness or anxiety
- Rapid or irregular heart beats
Diagnostic tests your cardiologist may use to confirm diagnosis includes the following:
- Electrocardiogram (ECG): an ECG records these electrical signals and can help your doctor detect irregularities in your heart’s rhythm and structure. You may have an ECG while you’re at rest or while exercising (stress electrocardiogram).
- Holter monitoring: a Holter monitor is a portable device you wear to record a continuous ECG, usually for 24 to 72 hours. Holter monitoring is used to detect heart rhythm irregularities that aren’t found during a regular ECG exam.
- Echocardiogram: this noninvasive exam, which includes an ultrasound of your chest, shows detailed images of your heart’s structure and function.
- Stress test: this type of test involves raising your heart rate with exercise or medicine while performing heart tests and imaging to check how your heart responds.
- Cardiac catheterization: during this test, a short tube (sheath) is inserted into a vein or artery in your leg (groin) or arm. A hollow, flexible and longer tube (guide catheter) is then inserted into the sheath. Aided by X-ray images on a monitor, your doctor threads the guide catheter through that artery until it reaches your heart. The pressures in your heart chambers can be measured, and dye can be injected. The dye can be seen on an X-ray, which helps your doctor see the blood flow through your heart, blood vessels and valves to check for abnormalities.
- Cardiac computerized tomography (CT) scan: this test is often used to check for heart problems. In a cardiac CT scan, you lie on a table inside a doughnut-shaped machine. An X-ray tube inside the machine rotates around your body and collects images of your heart and chest.
- Cardiac magnetic resonance imaging (MRI): during this test, you lie on a table inside a long tube-like machine that produces a magnetic field. The magnetic field produces pictures to help your doctor evaluate your heart.
What Are My Treatment Options for Coronary Artery Disease?
Treatment of coronary artery disease involves reducing your risk factors, taking prescribed medications as instructed and possibly undergoing minimally invasive or surgical procedures. It is important to see your cardiologist regularly to reduce your risk of heart attack or stroke.
Reducing your risk factors involves making lifestyle changes such as the following:
- Smoking cessation
- Dietary changes to reduce cholesterol, control blood pressure and manage blood sugar if you have diabetes
- Limiting alcohol consumption to one drink per day
- Increase your exercise/activity level to help achieve and maintain a healthy weight and reduce stress
Taking your medications as prescribed is important if lifestyle changes in itself are not enough to control your heart disease. These may include the following:
- Antiplatelet medications (aspirin, clopidogrel, prasugrel)
- Beta blockers (metoprolol, labetalol, propranolol)
- ACE inhibitors (benazepril, Ramipril, captopril)
- ARBs (losartan, olmesartan, valsartan)
- Anticoagulants (warfarin, xarelto, heparin, enoxaparin)
- Calcium channel blockers (amlodipine, diltiazem, nifedipine)
- Statins to lower cholesterol (atorvastatin, pravastatin, simvastatin)
- Digitalis medications (digoxin)
- Nitrates (nitroglycerin, isosorbide dinitrate, isosorbide mononitrate)
Procedures may be recommended to treat your coronary artery disease which could be either minimally invasive or surgical and include the following:
- Interventional procedures: this procedure is minimally invasive and involves your cardiologist accessing your heart using a long, thin tube (catheter) that is inserted into a blood vessel. Several types of balloons or catheters can be used to treat the plaque build up within the artery walls. Balloon angioplasty involves deployment of a special balloon at the end of the catheter that is inflated and deflated several times in order to compress the plaque against the walls of the artery. This widens the opening of the blood vessel, so blood is able to flow freely through it. In some instances a mesh-like metal tube called a stent may be placed within the artery to keep it open, which may be drug-eluting, meaning it is coated in a material that allows for emission of a drug over time that decreases the risk of plaque build-up. This procedure is completed either outpatient with patients going home the same day or may require an overnight hospital stay.
- Coronary artery bypass graft (CABG) surgery: if your cardiologist is unable to open your coronary arteries using a minimally invasive method, you will be evaluated by a cardiac surgeon for CABG surgery. During this procedure, one or more of your blocked coronary arteries is bypassed by a blood vessel graft to restore normal blood flow to the heart. These grafts are created using either the patients own arteries or veins, located in the chest, arm or leg. The graft goes around the clogged artery to create a new pathway for oxygen rich blood to flow to the heart. This requires a 5-7 day hospital stay.
- Enhanced external counterpulsation (EECP): for patients who have persistent angina symptoms and have exhausted the standard treatments without successful results, EECP may stimulate the openings or formation of small branches of blood vessels (collaterals) to create a natural bypass around narrowed or blocked arteries. EECP is a noninvasive treatment for people who have chronic, stable angina; who are not receiving adequate relief from angina by taking nitrate medications; and who do not qualify for a procedure such as bypass surgery, angioplasty or stenting. This procedure is outpatient and patients go home the same day.