Coronary Heart Disease

Introduction

During your lifetime, your heart will beat more than two and a half-billion times, pumping your blood and providing your body with the necessary elements for life. Your heart never takes a vacation nor does it ever stop for rest. In return, we might ask, what have you done for your heart?

What is it?

Coronary heart disease (CHD), also termed coronary artery disease or ischemic heart disease, is the most common form of heart disease and the most common cause of death in the United States. According to a report from the American Heart Association, in 2008 the estimated indirect and direct costs associated with CHD is projected to be $156.4 billion dollars.

The coronary arteries are large blood vessels in the surface of the heart that deliver blood to the heart muscle. Fatty plaques can build up in the arteries and block blood flow--a process called atherosclerosis. If the arteries become blocked, the heart muscle does not get enough oxygen, bringing ontriggering a variety of symptoms such as chest pain and shortness of breath, as well as heart muscle damage and even death.

The main mechanisms of angina (chest pain) are conditions that either decrease the supply of blood, or increase the demand for blood. Decreased supply is most commonly due to atherosclerosis (a build up of fatty deposits), or spasms in the arteries, which can limit the space through which blood flows to the heart.

An increase in demand takes place during exercise or exertion. The heart beats faster to supply the muscles and other organs with more oxygen in response to the increased demand. Chronic stable angina results when this increased demand for blood exceeds the supply to the coronary arteries. This can also occur during periods of stress, or extreme temperatures. Although spasms of the coronary arteries are the main cause of Prinzmetal's angina, approximately two thirds of people with this type of angina also have atherosclerosis in at least one vessel.

Coronary heart disease can manifest itself as:

Angina pectoris

Angina pectoris is pain or pressure felt in the middle of the chest, usually under the breastbone. The discomfort can range from crushing or squeezing to burning and aching, usually increasing with exertion and lessening with rest. The pain usually originates from the middle of the chest or slightly to the left, although sometimes the pain may seem to come from the upper stomach, neck, jaw or left arm. The pain is often accompanied by shortness of breath and sweating. Sometimes, individuals with coronary heart disease don't experience chest pain, but only difficulty breathing when they exert themselves.

In angina pectoris, the coronary arteries are partly blocked by fatty deposits of atherosclerosis. Upon exertion, the heart beats harder and faster and these blockages limit the flow of blood that the heart needs to accommodate the increased muscle activity. This brings on pain. Although less common, some individuals experience chest pain when at rest or when they are exposed to cold temperatures, a problem known as variant or Prinzmetal's angina. In most persons with variant angina, blockages in the arteries contribute to the problem although spasms in the coronary arteries are thought to be the primary mechanism resulting in pain.

Unstable Angina

Unstable angina is a more severe form of angina pectoris in which chest pain occurs with little exertion or even at rest. Often, unstable angina attacks individuals who have been previously diagnosed with the milder form of angina but sometimes, unstable angina is the first sign of coronary heart disease. Unstable angina is diagnosed when angina pain is experienced while resting or doing non-stressful tasks or if the angina pain is increasing in frequency or duration. Unstable angina is considered a medical emergency and immediate medical attention should be sought. Unstable angina usually occurs when plaque that has been partially blocking an artery in the heart suddenly ruptures and severely limits the blood flow to the heart muscle. This can progress to acute myocardial infarction, the technical name for a heart attack

Acute myocardial infarction, or heart attack

Acute myocardial infarction (heart attack) is a life-threatening condition that results from complete blockage of blood flow in one or more of the coronary arteries, thereby preventing blood flow to the heart muscle. As a result, the heart muscle can be injured or permanently damaged. The classic symptoms of a heart attack are:

  • Deep, crushing and severe squeezing chest pain usually lasting more than 20 minutes
  • Profuse sweating
  • Upset stomach
  • Shortness of breath
  • A sense of impending doom
  • Pain in the shoulders, neck or arms

Heart attacks can bring on congestive heart failure, abnormal heart rhythms, and death.

A blockage in the coronary arteries can be started by a blood clot, ulcers in the wall of the artery, plaque break-up within the artery, or hemorrhage within a plaque. The mechanism of coronary artery blockage is a heavily researched area. Currently, for example, researchers are studying the role of inflammation in coronary artery damage. They have found that the presence of an infection can attract inflammatory chemicals into the artery. This, in turn, encourages the formation of blood clots and blockages. There are also instances where coronary arteries can go into spasms that lead to narrowing of the artery and reduction of blood flow.

What causes it?

There is no exact single cause of coronary heart disease (CHD) but rather numerous factors that can contribute to or increase the risk of developing the condition. These factors can include lifestyle, heredity, age, and gender. To learn more about risk factors for coronary heart disease, click on "What are the Risk Factors?"

Who has it?

According to a 2008 American Heart Association (AHA) report, coronary heart disease is the leading cause of death in both men and women in the United States, causing 1 in every 5 deaths. In 2008, an estimated 770,000 Americans will suffer from a new coronary event and nearly 430,000 will suffer a second event. Americans will experience a coronary event approximately every 26 seconds, and will die from one about every 60 seconds. According to an the National Heart, Lung, and Blood Institute's (NHLBI) Framingham Study(FHS) study, men, over forty years of age, have a lifetime risk for developing CHD of 49% compared with women of the same age at 32%. CHD makes up more than 50% of all cardiovascular events in men and women age less than 75.

The National Center for Health Statistics estimates that if all forms of heart disease were eliminated, life expectancy would increase by almost 10 years. In comparison, if all forms of cancer were eliminated, the gain would only be three years.

What are the risk factors?

Risk factors are characteristics that may increase your chance for developing a condition. Factors that increase your chance of having or developing coronary heart disease include:

  • Age. Older people are more likely to develop coronary disease than younger people.
  • Male gender. Before age 60 or 70, men are more likely than women to develop coronary disease.
  • Family history of heart disease
  • Cigarette smoking. Smokers are two to four times more likely to develop coronary heart disease than non-smokers.
  • High blood pressure (or on blood pressure medication)
  • Diabetes. Diabetes greatly increases your risk of developing heart disease, especially when blood sugar levels are not controlled.
  • Low HDL cholesterol (less than 40 mg/dL) - HDL cholesterol is the "good cholesterol."
  • High LDL cholesterol - LDL cholesterol is the "bad cholesterol."
Other characteristics that may increase your chance of developing coronary heart disease include:
  • Obesity. Being overweight causes your heart to work harder. It also raises your blood pressure, LDL cholesterol ("bad" cholesterol), and triglycerides. Your HDL cholesterol ("good" cholesterol) is decreased, and your risk of developing diabetes increases. Losing weight may help decrease your risk of heart disease.
  • Physical inactivity. Regular moderate-to-vigorous physical activity can help prevent heart and blood vessel disease. Always talk to you doctor before you start an exercise program.
  • Emotional stress
  • Depression
  • Alcohol consumption. Too much alcohol can raise your blood pressure and contribute to high triglycerides and other problems.

What are the symptoms?

Symptoms of coronary heart disease may last for 30 seconds to 30 minutes. The pain may radiate to the left shoulder, left arm, or the jaw. Occasionally, the pain may radiate to the right arm. Common symptoms include:

  • Sensation of pressure or heavy weight on the chest
  • Burning sensation
  • Crushing or squeezing sensation
  • Feeling of tightness
  • Shortness of breath
  • Sweating
  • Lightheadedness
  • Nausea
  • Gradual increase in intensity followed by gradual fading away

Women are less likely to experience these "typical" symptoms, but are more likely to have unusual symptoms, such as nausea, fatigue, or indigestion. Other "atypical" or unusual symptoms include back, neck, or jaw pain, vomiting, weakness, and dizziness. Women are also more likely to experience "pre-heart attack" symptoms, which include unusual fatigue, sleep disturbance, shortness of breath, chest pain, indigestion, anxiety, and pain in the upper back or shoulder blade. These "pre-heart attack" symptoms generally occur four to six months to one week before the actual heart attack. However, some patients have reported symptoms up to two years before their heart attack. You should talk to your doctor if you experience any of these symptoms.

Depending on the type of angina, precipitating factors may include:

  • Relationship to exercise
  • Effort involving the use of your arms above your head
  • Cold temperatures
  • Walking against a strong wind
  • Walking after eating a large meal
  • Fright or anger
  • Sexual intercourse

How is it treated?

There are different types of coronary heart disease. Treatment depends on which type is being treated.

Angina (Chronic stable and Unstable)

In 2002, the American College of Cardiology and the American Heart association published guidelines for treating angina that represented a consensus statement that was the result of numerous studies. Guidelines have also been published by organizations like the Agency for Health Care Policy and Research (AHCPR). All guidelines advocate a step approach, which includes lifestyle changes and the use of aspirin, nitrates, ACE inhibitors, beta blockers, and calcium antagonists. Drugs to lower cholesterol are also recommended if needed.

As in other heart diseases, the first step in treating angina is making lifestyle changes. These include smoking cessation, weight loss, regular exercise, eating a diet that is high in fiber and low in fat, and moderating one's alcohol consumption.

Then, if there are no contraindications, patients should be considered for daily aspirin therapy and nitroglycerin that is dissolved under the tongue when needed for angina attacks.

If patients require maintenance therapy to prevent angina attacks, then beta blockers are the preferred therapy due to their documented efficacy in post heart attack patients. If beta blockers are contraindicated or not tolerated, then long acting nitrates or calcium antagonists should be considered. Similarly, if beta blockers are tolerated, but the patient still experiences anginal episodes, then the addition of a long acting nitrate or a calcium channel antagonist should be investigated.

Most angina episodes are the result of partial blockage of coronary arteries resulting from plaque build-up. Because high levels of cholesterol play a role in this accumulation of arterial plaque, clinicians recommend lipid-lowering therapy for all patients with high cholesterol levels, and for high-risk patients who have elevated or normal cholesterol levels (see Treating Hypercholesterolemia).

Acute myocardial infarction, or heart attack

The main treatment goals of the survivors of heart attack are to prevent another heart attack, and to decrease the symptoms that arise from heart failure and narrowing of the coronary arteries. A related goal is to minimize the need to use coronary bypass surgery. In this procedure, surgeons graft a vein, usually taken from the patient's leg, from the aorta to the coronary artery, thus skipping over, or bypassing, the obstructed area.

A step approach to reaching the goals of heart attack therapy is based on considerations of research, cost effectiveness and an assessment of the risk status of the patient.

In all patients, the first step is modifying lifestyle-related risk factors. Patients should quit smoking, lose weight if necessary, exercise regularly, follow a diet that is high in fiber and low in fat, and keep stress to a minimum.

All patients who have suffered a heart attack should be started on daily aspirin therapy unless contraindicated or intolerable. In addition, all heart attack patients should receive beta blockers unless contraindicated.

Patients with decreased heart function after a heart attack are at high risk for developing congestive heart failure and should receive an ACE inhibitor. Finally, because of documented efficacy in preventing a recurrent heart attack, all patients with elevated LDL-cholesterol levels should be given lipid-lowering therapy with an HMG CoA reductase inhibitor, also known as a statin. The goal of statin therapy is to decrease the b"ad cholesterol" (LDL-cholesterol) by 50% or to less than 100 mg/dl (see Treating Hypercholesterolemia). In patients that are "very high risk" (those with established heart disease and multiple major risk factors including diabetes, metabolic syndrome, and current smokers), a more aggressive LDL goal of <70 mg/dL may be encouraged

Sometimes surgery remains as the only option for patients who have suffered a heart attack. Procedures include a bypass operation (described above) or numerous methods to open up the clogged artery such as angioplasty or coronary stent placement. In angioplasty, surgeons insert a balloon-tipped catheter into the arterial system. Once it reaches the blocked coronary artery, the doctor inflates the balloon so that it flattens the plaque against the wall of the artery. A similar procedure involves the placement of a coronary stent (a small tubular object which resembles the spring in a ball-point pen) in the area of the artery which was occluded. The stent gives the artery stability and helps to prevent reocclusion.

Helping Yourself

Although there are many effective treatments for coronary heart disease, prevention remains our most important weapon. By reducing risk factors, not only can you prevent heart disease, you can delay its progression and, in some cases, reverse the process. While you can't do much to change your age or gender, you can make lifestyle modifications in the following areas:

  • Smoking cessation
  • A heart healthy diet
  • Regular exercise
  • Weight loss
  • Keeping stress to a minimum

Stopping smoking will not only reduce your risk of heart disease but also may improve your lung capacity, reduce the number and intensity of the colds you catch, and prevent cancer of the throat, lung, and other organs.

A heart healthy diet includes lots of fresh fruits and vegetables and is low in saturated fat and cholesterol. Avoiding fast food or pre-processed foods will help you minimize the amount of fat in your diet. Drinking one alcoholic beverage daily may reduce your chance of developing heart disease.

A regular exercise program (e.g., 30 minutes 4 times per week) should include both aerobic exercise, such as walking, jogging, or swimming, as well as anaerobic exercise, such as weight lifting. Before beginning or making changes to your exercise regimen, be sure to talk with your doctor. If you are overweight, diet and exercise can help you to lose weight and reduce your risk of coronary heart disease.

If drug therapy is indicated to prevent or treat coronary artery disease, you must remain active in your care and understand the reasons for taking each medication as well as the importance of taking the medications as directed.

What is on the horizon?

Research is currently taking place to find the optimal timing of therapy to prevent complications from coronary heart disease. Using the medications that are currently available at different times in the development of coronary heart disease can have a huge impact on the prevention of heart attack and stroke. Stem cells are also being researched for the treatment of coronary heart disease.

Researchers with the National Institutes of Health are currently conducting a study looking at the use of a man- made amino acid, EDTA, for the treatment of coronary heart disease. Past studies that included EDTA did not show any benefit; however, this study is larger and hoping to prove otherwise.

Evidence from a recent study that investigated cardiovascular risk factors in the children of parents who survived to 85 found that people whose parents live longer were less likely to develop high blood pressure, high cholesterol, and other risk factors for coronary heart disease in middle age than their peers whose parents died younger. Researchers from the long-standing Framingham Heart Study (FHS), a program of the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health, are expanding their research into other areas such as the role of genetic factors in coronary heart disease as well as the use of biomarkers and new diagnostic tests to identify individuals at high risk.

References

Agency for Health Care Policy and Research. Clinical Practice Guidelines, Number 10: Unstable Angina; Diagnosis and Management. May 1994; Diagnosis and Management;November 1998

American College of Cardiology Foundation, American Heart Association. ACC/AHA 2002 guideline update for the management of patients with chronic stable angina: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to update the 1999 guidelines). Bethesda (MD): American College of Cardiology Foundation; 2002. American Heart Association. 2002 and Stroke Statistical Update. Dallas, TX: American Heart Association; 2001

American Heart Association. Heart Attack and Angina Statistics. Available at: http://www.americanheart.org/presenter.jhtml?identifier=4591. Accessed October 2003 and February 2008.

Deedwania PC. Amsterdam EA. Vagelos RH. Evidence-based, cost-effective risk stratification and management after myocardial infarction. California Cardiology Working Group on Post-MI Executive Summary of the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA 2001 May 16; 285(19):2486-97

Framingham Heart Study. Information for Researchers. National Heart Lung and Blood institute. Available at: http://www.nhlbi.nih.gov/about/framingham/index.html. Accessed February 2007 and February 2008.

Frye R., et al. Treatment of chronic stable angina. American Journal of Cardiology 1992;70:260-310

Heart Healthy Women. Available at: http://www.hearthealthywomen.org. Accessed February 2007 and February 2008. Management. Archives of Internal Medicine 1997 Feb 10;157(3):273-280

National Coalition for Women with Heart Disease. Available at: http://www.womenheart.org/index.asp. Accessed February 2007 and February 2008.

National Heart Lung and Blood Institute. Coronary Artery Disease. Available at: http://www.nhlbi.nih.gov/health/dci/Diseases/Cad/CAD_WhatIs.html. Accessed February 2007 and February 2008.

Rosamond, W et al. Heart Disease and Stroke Statistics?2007 Update. A report from the AHA Statistics Committee and Stroke Statistics Subcommittee. Circulation 2007; 115: 69-171. Available at: http://circ.ahajournals.org/cgi/reprint/115/5/e69. Accessed February 2007 and February 2008.

Heart Disease and Stroke Statistics ?2008? Update. A report from the AHA Statistics Committee and Stroke Statistics Subcommittee. Circulation 2008; 117;e25-e146. Available at: http://circ.ahajournals.org/cgi/reprint/CIRCULATIONAHA.107.187998. Accessed February 2008.

National Center for Complementary and Alternative Medicine. Learn More About Chelation Therapy and the Study.Updated October 2007. Available at URL: http://nccam.nih.gov/chelation/chelationstudy.htm. Accessed February 2008.

Sacks FM, Pfeffer MA, Maye LA, et al, for the Cholesterol and Recurrent Events Trial Investigators. The effect of pravastatin on coronary events after myocardial infarction in patients with average cholesterol levels. New England Journal of Medicine 1996; 335:1001-9.

Coronary Heart Disease Health Condition Last Updated: February 2008

Note: The above information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist, or other healthcare professional. It is not intended to diagnose a health condition, but it can be used as a guide to help you decide if you should seek professional treatment or to help you learn more about your condition once it has been diagnosed.

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