What is acute coronary syndrome

Acute coronary syndrome is a term for any condition that suddenly stops (or severely reduces) blood from flowing to the heart. When blood cannot flow to the heart, the heart muscle can become damaged. Acute coronary syndrome, an umbrella term for situations where the blood supplied to the heart muscle is suddenly blocked. The blockage can be sudden and complete, or it can come and go – clot, break open, then clot again. One condition under the umbrella of acute coronary syndrome is myocardial infarction (heart attack) — when cell death results in damaged or destroyed heart tissue. Even when acute coronary syndrome causes no cell death, the reduced blood flow alters heart function and indicates a high risk of heart attack. Heart attack (myocardial infarction) and unstable angina are both acute coronary syndromes ¹. Doctors use the broad term acute coronary syndrome regularly, but usually only among themselves and in the medical literature. Doctors usually tell their patients “You’re having a heart attack” instead of saying “You’re having an acute coronary syndrome.”

Acute coronary syndrome often causes severe chest pain or discomfort. It is a medical emergency that requires prompt diagnosis and care. Treatment goals include improving blood flow, treating complications and preventing future problems.

Outlook (prognosis) for acute coronary syndrome

How well you do after an acute coronary syndrome depends on:

• How quickly you get treated
• The number of arteries that are blocked and how bad the blockage is
• Whether your heart is damaged and where the damage is

In general, the quicker your artery gets unblocked, the less damage you will have to your heart. People tend to do best when the blocked artery is opened within a few hours from the time symptoms start.

Acute coronary syndrome possible complications

In some cases, acute coronary syndrome can lead to other health problems including:

• Abnormal heart rhythms
• Heart attack
• Heart failure, which happens when the heart cannot pump enough blood

Acute coronary syndrome guidelines

The goals of the American College of Cardiology and the American Heart Association have collaborated with the National Heart, Lung, and Blood Institute to develop clinical practice guidelines for assessment of cardiovascular risk, lifestyle modifications to reduce cardiovascular risk, management of blood cholesterol in adults, and management of overweight and obesity in adults ².

These guidelines are meant to define practices that meet the needs of patients in most circumstances and are not a replacement for clinical judgment. The ultimate decision about care of a particular patient must be made by the healthcare provider and patient in light of the circumstances presented by that patient. As a result, situations might arise in which deviations from these guidelines may be appropriate. These considerations notwithstanding, in caring for most patients, clinicians can employ the recommendations confidently to reduce the risks of atherosclerotic cardiovascular disease (CVD) events.

Diet Recommendations for LDL-C “bad cholesterol” Lowering

Advise adults who would benefit from LDL-C “bad cholesterol” lowering to:

• Consume a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts; and limits intake of sweets, sugar-sweetened beverages, and red meats.
  • Adapt this dietary pattern to appropriate calorie requirements, personal and cultural food preferences, and nutrition therapy for other medical conditions (including diabetes).
  • Achieve this pattern by following plans such as the DASH dietary pattern, the US Department of Agriculture (USDA) Food Pattern, or the American Heart Association (AHA) Diet.
• Aim for a dietary pattern that achieves 5% to 6% of calories from saturated fat.

Sodium and Blood Pressure

Diet Recommendations for Blood Pressure Lowering

1. Advise adults who would benefit from blood pressure (BP) lowering to:

• a. Consume a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts; and limits intake of sweets, sugar-sweetened beverages, and red meats.
  • i. Adapt this dietary pattern to appropriate calorie requirements, personal and cultural food preferences, and nutrition therapy for other medical conditions (including diabetes).
  • ii. Achieve this pattern by following plans such as the DASH dietary pattern, the USDA Food Pattern, or the AHA Diet.

2. Advise adults who would benefit from blood pressure lowering to:

• a. Consume no more than 2400 mg of sodium/day;
• b. Further reduction of sodium intake to 1500 mg/day can result in even greater reduction in BP;
• c. Even without achieving these goals, reducing sodium intake by at least 1000 mg/day lowers BP.
• d. Combine the DASH dietary pattern with lower sodium intake.

Physical Activity: Lipids and Blood Pressure

Physical Activity Recommendations

Most health benefits occur with at least 150 minutes (2 hours and 30 minutes) a week of moderate-intensity physical activity, such as brisk walking. Additional benefits occur with more physical activity ³.

1. In general, advise adults to engage in aerobic physical activity to reduce LDL “bad” cholesterol and non–HDL-cholesterol: 3 to 4 sessions per week, lasting on average 40 minutes per session, and involving moderate- to vigorous-intensity physical activity.

2. In general, advise adults to engage in aerobic physical activity to lower blood pressure (BP): 3 to 4 sessions per week, lasting on average 40 minutes per session, and involving moderate- to vigorous-intensity physical activity.

Acute coronary syndrome causes

Acute coronary syndrome usually results from the buildup of fatty deposits (plaques) in and on the walls of coronary arteries, the blood vessels delivering oxygen and nutrients to heart muscles.

A fatty substance called plaque can build up in the arteries that bring oxygen-rich blood to your heart. Plaque is made up of cholesterol, fat, and other waste products.

Plaque can block blood flow in 2 ways:

• It can cause an artery to become so narrow over time that it becomes blocked enough to cause symptoms.
• The plaque tears suddenly and a blood clot forms around it, severely narrowing or blocking the artery.

When a plaque deposit ruptures or splits, a blood clot forms. This clot obstructs the flow of blood to heart muscles.

When the supply of oxygen to cells is too low, cells of the heart muscles can die. The death of cells — resulting in damage to muscle tissues — is a heart attack (myocardial infarction).

Even when there is no cell death, an inadequate supply of oxygen still results in heart muscles that don’t work correctly or efficiently. This dysfunction may be temporary or permanent. When acute coronary syndrome doesn’t result in cell death, it is called unstable angina.

• Many risk factors for heart disease may lead to an acute coronary syndrome.

Risk factors for acute coronary syndrome

The risk factors for acute coronary syndrome are the same as those for other types of heart disease. Acute coronary syndrome risk factors include:

• Older age (older than 45 for men and older than 55 for women)
• High blood pressure
• High blood cholesterol
• Cigarette smoking
• Lack of physical activity
• Unhealthy diet
• Obesity or overweight
• Diabetes
• Family history of chest pain, heart disease or stroke
• For women, a history of high blood pressure, preeclampsia or diabetes during pregnancy

Acute coronary syndrome prevention

There is a lot you can do to help prevent acute coronary syndrome .

• Eat a heart-healthy diet. Have plenty of fruits, veggies, whole grains, and lean meats. Try to limit foods high in cholesterol and saturated fats, since too much of these substances can clog your arteries.
• Get exercise. Aim to get at least 30 minutes of moderate exercise most days of the week.
• Lose weight, if you are overweight.
• Quit smoking. Smoking can damage your heart. Ask your doctor if you need help quitting.
• Get preventive health screenings. You should see your doctor for regular cholesterol and blood pressure tests and learn how to keep your numbers in check.
• Manage health conditions, such as high blood pressure, high cholesterol, or diabetes.

Acute coronary syndrome symptoms

The most common symptom of acute coronary syndrome is chest pain or discomfort, which may involve pressure, tightness or fullness. The chest pain may come on quickly, come and go, or get worse with rest. Other symptoms can include:

• Pain or discomfort in one or both arms, in the shoulder, the jaw, neck, back or stomach area
• Discomfort that feels like tightness, squeezing, crushing, burning, choking, or aching
• Discomfort that occurs at rest and does not easily go away when you take medicine
• Shortness of breath (dyspnea)
• Anxiety
• Nausea or vomiting
• Indigestion
• Sudden, heavy sweating (diaphoresis)
• Feeling dizzy, lightheaded or fainting
• Fast or irregular heartbeat
• Unusual or unexplained fatigue
• Feeling restless or apprehensive

While chest pain or discomfort is the most common symptom associated with acute coronary syndrome, signs and symptoms may vary significantly depending on your age, sex and other medical conditions.

• Women, people with diabetes and older people often experience these other symptoms, although chest pain is common for them as well.

These symptoms should be taken seriously. If you experience chest pain or other symptoms, call your local emergency number immediately.

Chest pain caused by acute coronary syndromes can come on suddenly, as is the case with a heart attack. Other times, the pain can be unpredictable or get worse even with rest, both hallmark symptoms of unstable angina. People who experience chronic chest pain resulting from years of cholesterol buildup in their arteries can develop an acute coronary syndrome if a blood clot forms on top of the plaque buildup.

Acute coronary syndrome diagnosis

Your health care provider will do an exam, listen to your chest with a stethoscope, and ask about your medical history.

Tests for acute coronary syndrome include:

• Electrocardiogram (ECG). An ECG is usually the first test your doctor will run. It measures your heart’s electrical activity. During the test, you will have small pads taped to your chest and other areas of your body. This test measures electrical activity in your heart via electrodes attached to your skin. Abnormal or irregular impulses can indicate poor heart function due to a lack of oxygen to the heart. Certain patterns in electrical signals may indicate the general location of a blockage. The test may be repeated several times.
• Blood test. Some blood tests help show the cause of chest pain and see if you are at a high risk for a heart attack. A troponin blood test can show if the cells in your heart have been damaged. This test can confirm you are having a heart attack.

The information from these two tests — as well as signs and symptoms — may provide the primary basis for a diagnosis of acute coronary syndrome and may determine whether the condition can be classified as a heart attack or unstable angina.

Other tests may be ordered to characterize the condition more thoroughly, rule out other causes of symptoms, or combine diagnostic and treatment interventions.

Echocardiogram. This test uses sound waves to look at your heart. It shows if your heart has been damaged and can find some types of heart problems.

Coronary angiography may be done right away or when you are more stable. This test:

• This procedure uses X-ray imaging to see your heart’s blood vessels. A long, tiny tube (catheter) is threaded through an artery, usually in your arm or groin, to the arteries in your heart. A liquid dye, which can be detected by X-rays, is sent through the tube to your arteries. Multiple X-ray images of your heart can reveal blockage or narrowing of the arteries. The catheter may also be used for treatments.
• Can help your doctor decide which treatments you need next.

Other tests to look at your heart that may be done while you are in the hospital include:

• Exercise stress test. A stress test assesses how well your heart functions when you exercise — when your heart needs to work harder. In some cases, you may receive a medication to increase your heart rate rather than exercising. This test is only done when there is no evidence of acute coronary syndrome or another life-threatening heart condition when you are at rest. During the stress test, heart function may be assessed by an ECG, echocardiogram or myocardial perfusion imaging.
• Myocardial perfusion imaging (MPI). This test shows how well blood flows through your heart muscle. A tiny, safe amount of radioactive substance is injected into your blood. A specialized camera detects the blood as it moves through your heart to reveal whether enough blood is flowing through heart muscles and where blood flow is reduced.
• Echocardiogram. An echocardiogram uses sound waves, directed at your heart from a wand-like device, to produce a live image of your heart. An echocardiogram can help determine whether the heart is pumping correctly.
• Stress echocardiography.
• Computerized tomography (CT) angiogram. A CT angiogram uses a specialized X-ray technology that can produce multiple images — cross-sectional 2-D slices — of your heart. These images can detect narrowed or blocked coronary arteries.

Acute coronary syndrome treatment

Immediate treatment goals are to relieve pain and distress, improve blood flow, and restore heart function as quickly and as best as possible. Long-term treatment goals are to improve overall heart function, manage risk factors and lower the risk of a heart attack. A combination of drugs and surgical procedures may be used to meet these goals.

Your doctor may use medicines, surgery, or other procedures to treat your symptoms and restore blood flow to your heart. Your treatment depends on your condition and the amount of blockage in your arteries. Your treatment may include:

• Medicine. Your doctor may give you one or more types of medicine, including aspirin, beta blockers, statins, blood thinners, Angiotensin converting enzyme (ACE) inhibitors, or nitroglycerin. These medicines may help prevent or break up a blood clot, treat high blood pressure or angina, relieve chest pain, and stabilize your heart.
• Angioplasty. This procedure opens the clogged artery using a long, thin tube called a catheter. The tube is placed in the artery and the provider inserts a small deflated balloon. The balloon is inflated inside the artery to open it up. Your doctor may insert a wire tube, called a stent, to keep the artery open.
• Bypass surgery. This is surgery to route the blood around the artery that is blocked.

Medications

Depending on your diagnosis, medications for emergency care or ongoing management — and in some cases both — may include the following:

• Thrombolytics, also called clot busters, help dissolve a blood clot that’s blocking an artery.
• Nitroglycerin improves blood circulation by temporarily widening blood vessels.
• Antiplatelet drugs, which help prevent blood clots from forming, include aspirin, clopidogrel (Plavix), prasugrel (Effient) and others.
• Beta blockers help relax your heart muscle and slow your heart rate, thereby decreasing the demand on your heart and lowering your blood pressure. These include metoprolol (Lopressor), nadolol (Corgard) and several others.
• Angiotensin-converting enzyme (ACE) inhibitors expand blood vessels and improve blood flow, allowing the heart to work more easily and efficiently. They include lisinopril (Prinivil, Zestril), benazepril (Lotensin) and several others.
• Angiotensin receptor blockers (ARBs), which help control blood pressure, include irbesartan (Avapro), losartan (Cozaar) and several others.
• Statins lower the amount of cholesterol circulating in the blood and may stabilize plaque deposits, making them less likely to rupture. Statins include atorvastatin (Lipitor), simvastatin (Zocor) and several others.

Surgery and other procedures

If medications aren’t enough to restore blood flow to your heart muscles, your doctor may recommend one of these procedures:

• Angioplasty and stenting. In this procedure, your doctor inserts a long, tiny tube (catheter) into the blocked or narrowed part of your artery. A wire with a deflated balloon is passed through the catheter to the narrowed area. The balloon is then inflated, opening the artery by compressing the plaque deposits against your artery walls. A mesh tube (stent) is usually left in the artery to help keep the artery open.
• Coronary bypass surgery. With this procedure, a surgeon takes a piece of blood vessel (graft) from another part of your body and creates a new route for blood that goes around, or bypasses, a blocked coronary artery.

Lifestyle and home remedies

An important step to prevent a heart attack is to make changes in your lifestyle that promote heart health and lower your risk of heart disease. These interventions include the following:

• Don’t smoke. If you smoke, quit. Talk to your doctor if you need help quitting. Also, avoid second-hand smoke.
• Eat a heart-healthy diet. Eat a diet with lots of fruits and vegetables, whole grains, and moderate amounts of low-fat dairy and lean meats.
• Be active. Get regular exercise and stay physically active. If you have not been exercising regularly, talk to your doctor about the best exercise to begin a healthy and safe routine.
• Check your cholesterol. Have your blood cholesterol levels checked regularly at your doctor’s office. Avoid high-fat, high-cholesterol meat and dairy. If your doctor has prescribed a statin or other cholesterol-lowering medication, take it daily as directed by your doctor.
• Control your blood pressure. Have your blood pressure checked regularly as recommended by your doctor. Take blood pressure medicine daily as recommended.
• Maintain a healthy weight. Excess weight strains your heart and can contribute to high cholesterol, high blood pressure, diabetes, heart disease and other conditions.
• Manage stress. To reduce your risk of a heart attack, reduce stress in your day-to-day activities. Rethink work habits and find healthy ways to minimize or deal with stressful events in your life. Talk to your doctor or a mental health care professional if you need help managing stress.
• Drink alcohol in moderation. If you drink alcohol, do so in moderation. Drinking more than one to two alcoholic drinks a day can raise blood pressure.

1. Acute Coronary Syndrome. http://www.heart.org/HEARTORG/Conditions/HeartAttack/AboutHeartAttacks/Acute-Coronary-Syndrome_UCM_428752_Article.jsp[↩]
2. 2013 AHA/ACC Guideline on Lifestyle Management to Reduce Cardiovascular Risk. A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. http://circ.ahajournals.org/content/129/25_suppl_2/S76.long[↩]
3. Physical Activity Guidelines Advisory Committee. Physical Activity Guidelines Advisory Committee Report, 2008. Washington, DC: US Department of Health and Human Services; 2008:1–683[↩]