Acute coronary syndrome refers to three types of coronary artery disease. All of them involve dangerous plaque buildup in the arteries that supply blood to your heart muscle.

Coronary artery disease (CAD) and acute coronary syndrome (ACS) are related terms that describe reduced blood flow to the heart muscle, a condition that sets the stage for a heart attack.

ACS is an umbrella term that refers to the types of CAD caused by the buildup of plaque in the coronary arteries.

The risk factors for both ACS and CAD include conditions such as high cholesterol and smoking. CAD and ACS may be treated successfully before a heart attack or other complications as long as they’re diagnosed early.

Emergency treatment following a heart attack is also possible, but the damage to heart tissue can cause long-term health challenges.

CAD refers to the narrowing of the arteries supplying your heart with oxygenated blood. It’s the most common form of heart disease.

CAD is usually thought of as the result of plaque buildup in the arteries, a condition known as obstructive coronary artery disease. When plaque, made up of cholesterol, fats, and other substances, builds up inside the arteries, it’s called atherosclerosis.

Plaque narrows the lumen, the opening through which blood travels, and makes the arteries stiffer and less able to widen and constrict in response to changing conditions in your body.

Obstructive CAD is diagnosed when atherosclerosis restricts circulation to the point where the heart can become starved for a sufficient and steady supply of nutrient-rich blood.

Plaque can also rupture, causing a blood clot to form, blocking or significantly reducing blood flow in a coronary artery. In either case, a heart attack can follow.

What are the symptoms of CAD?

Symptoms for all types of CAD can include the following:

  • chest pain, pressure, or tightness
  • fatigue
  • lightheadedness
  • nausea
  • pain in the shoulder, arm, neck, jaw or upper back
  • shortness of breath
  • weakness

However, a person can have buildup of plaque in one or more arteries and have no noticeable symptoms. For some people, a heart attack is the first CAD symptom they experience.

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ACS includes types of CAD that are specifically related to plaque buildup in the coronary arteries.

The forms of ACS are distinguished by their severity, as well as where the blockage occurs and how long blood flow to the heart is restricted or cut off entirely. And while CAD can be present without any symptoms, ACS is always symptomatic. ACS symptoms are similar to those of CAD.

The three types of CAD that fall under the ACS umbrella are:

Unstable angina

Chest pain triggered by a reduction in blood flow to the heart muscle is called angina. When it occurs during physical exertion, when the heart is working harder than normal, it’s called stable angina.

When this type of chest pain emerges at any time — even during rest — it’s known as unstable angina. Unstable angina, a type of ACS, is considered more dangerous and a precursor to a heart attack.

Non-ST-elevation myocardial infarction (NSTEMI)

NSTEMI is a type of heart attack that may be detected with a blood test, but not always by an electrocardiogram (ECG). It occurs when blood flow isn’t completely blocked or if the blockage lasts a short time.

ST-elevated myocardial infarction (STEMI)

STEMI is a much more serious heart attack than can be diagnosed with a blood test or an ECG. It’s characterized by coronary artery blockage that lasts a long time and injures a significant amount of heart muscle tissue.

Anyone can develop CAD and ACS, but there are some important risk factors, some of which are within your control. These include:

Advancing age is also a major risk factor for obstructive CAD, as atherosclerosis can develop over a lifetime.

The Heart and Stroke Foundation of Canada also reports that about 90% of the people who experience SCAD are women, and most of them are between the ages of 30 and 60.

The main goals of ACS and CAD treatment are to relieve symptoms and restore healthy blood flow to the heart muscle.

ACS treatment usually includes medications, such as:

Procedures to treat ACS (obstructive CAD) include:

  • angioplasty, in which a small mesh tube is inserted into a coronary artery at the site of blockage to open up the lumen
  • coronary artery bypass surgery (CABG), which uses a blood vessel taken from another part of the body and attached to the heart to reroute blood flow around a major blockage.

Acute coronary syndrome includes types of coronary artery disease that involve the buildup of plaque in the coronary arteries.

If you’ve been diagnosed with some type of heart disease and been told you are at high risk for a heart attack, be sure to work with your healthcare team to learn about the symptoms of a heart attack or worsening heart disease, and to take any preventive steps you can.

Preventative steps include keeping up with your doctor appointments and taking all medications as prescribed. You should also stick to a healthy diet and avoid smoking, excessive alcohol consumption, and too much stress.

Following these heart-healthy recommendations may help you live a long time with cardiac conditions such as ACS and CAD.