Genetic Test Helps Improve Outcomes in Heart Stent Patients

Pittsburgh: A genetic test recently implemented at UPMC Presbyterian can significantly reduce the risk of cardiovascular events by helping to identify more effective medication for some heart patients, according to the results of a large study conducted in part at the University of Pittsburgh and UPMC. The findings are being presented today at the American Heart Association’s Scientific Sessions in New Orleans.The test identifies a genetic deficiency that affects the body’s ability to activate clopidogrel, a common anti-clotting drug given after a coronary artery stent is inserted. About 30 percent of all patients have the genetic deficiency, which can lead to decreased clopidogrel effectiveness and increased risk for adverse cardiovascular events, such as strokes, heart attacks and death.

Large Decrease in Coronary Heart Disease in U.S.

JAMA: The incidence of coronary heart disease in the U.S. declined nearly 20 percent from 1983 to 2011, according to a study appearing in the November 15 issue of JAMA. Diagnosis and control of coronary heart disease (CHD) risk factors have received particular emphasis in guidelines issued since 1977 (blood pressure) and 1985 (lipids). Yet on a population level, little is known about how these efforts have altered CHD incidence and its association with modifiable risk factors. Michael J. Pencina, Ph.D., of the Duke University Medical Center, Durham, N.C., and colleagues pooled individual patient-level data from 5 observational cohort studies available in the National Heart, Lung, and Blood Institute Biologic Specimen and Data Repository Information Coordinating Center. Two analytic data sets were created: 1 set with baseline data collected from 1983 through 1990 (early era) with follow-up from 1996 through 2001, and l set with baseline data collected from 1996 through 2002 (late era) with follow-up from 2007 through 2011.

Association between sugary diet and coronary artery disease

Lund University: What connection is there between food and drink with added sugar and coronary artery disease? Until recently, the question had been inadequately answered by research, but an extensive study from Lund University in Sweden has now contributed important clues. The study in question focuses on sucrose. Sucrose occurs naturally in fruit and vegetables, but the majority of our consumption is through added sucrose. Besides sweetened beverages, cakes and sweets, sucrose is added to many ordinary foods, such as dairy products, bread and jam. In Sweden, sucrose is the most common form of added sugar.

Yoga for secondary prevention of coronary heart disease

Cochrane: Coronary heart disease (CHD) is a major cause of early cardiovascular-related illness and death in most developed countries. Secondary prevention is a term used to describe interventions that aim to prevent repeat cardiac events and death in people with established CHD. Individuals with CHD are at the highest risk of coronary events and death. Lifestyle modifications play an important role in secondary prevention. Yoga has been regarded as both a type of physical activity and a stress management strategy.

Yoga for secondary prevention of coronary heart disease

Cochrane: Coronary heart disease (CHD) is a major cause of early cardiovascular-related illness and death in most developed countries. Secondary prevention is a term used to describe interventions that aim to prevent repeat cardiac events and death in people with established CHD. Individuals with CHD are at the highest risk of coronary events and death. Lifestyle modifications play an important role in secondary prevention. Yoga has been regarded as both a type of physical activity and a stress management strategy. The physical and psychological benefits of yoga are well accepted, yet inappropriate practice of yoga may lead to musculoskeletal injuries, such as muscle soreness and strain.

CT Angiography Links Arterial Plaque with Diabetes, Blood Pressure, Cholesterol

RSNA: Non-calcified arterial plaque is associated with diabetes, high systolic blood pressure and elevated "bad" cholesterol levels in asymptomatic individuals, according to a new study published online in the journal Radiology. Coronary artery disease (CAD) is the leading cause of death in men and women worldwide, accounting for 17 million deaths annually. Current treatment strategies focus on cardiovascular risk and serum cholesterol levels rather than direct assessment of extent of disease in the coronary arteries.

Tong-xin-luo capsule for coronary heart disease after percutaneous coronary intervention

Cochrane: What is the efficacy and safety of chinese herbal medicine Tong-xin-luo capsules in preventing cardiovascular events after percutaneous coronary intervention, a procedure involving placing a stent to open up the heart's blood vessels, in patients with coronary heart disease? Coronary heart disease is a major cause of mortality globally. Percutaneous coronary intervention is regarded as a standard treatment for coronary heart disease to improve symptoms of heart-related chest pain. However, a major drawback of percutaneous coronary intervention is the need for a repeat procedure due to symptoms related to recurring narrowing of the heart's blood vessels. Previous studies have indicated that Tong-xin-luo capsule, a Chinese herbal medicine product, might be effective in preventing recurrence of narrowing of a blood vessel after percutaneous coronary intervention.

Coronary heart disease is leading cause of avoidable deaths

British Heart Foundation: Coronary heart disease (CHD) is the leading single cause of avoidable death, according to the latest statistics from the Office for National Statistics. There were nearly 20,000 avoidable deaths from CHD in 2013, nearly a fifth (17%) of all avoidable deaths in England and Wales. Deaths are considered avoidable through good quality healthcare or wider public health interventions, such as changes to lifestyle. Figures reveal that CHD was the most common cause of avoidable deaths for males.

Short people may have an increased risk of heart disease

NHS: "Shorter people at greater risk of heart disease, new research finds," reports The Guardian. It reports that a study of nearly 200,000 people has found that for every 2.5 inches (6.35cm) less in height, there is a 13.5% increased risk of coronary heart disease or CHD (also known as coronary artery disease). This means that someone who is 5ft (1.52m) would have a 32% increased risk of CHD compared to someone who is 5ft 6 (1.71m). Previous research identified the link between shorter adult height and increased risk of CHD but why this might be was not known. It is thought that environmental factors could be involved. For example a person fed a poor diet in childhood could grow up both shorter than average and unhealthy. This current study attempted to create a clearer picture by looking for genetic variations linked to short stature that were also linked to CHD.

Antidepressant Zoloft Increases Coronary Atherosclerosis in Animal Model

Wake Forest: Zoloft, a commonly prescribed antidepressant caused up to a six-fold increase in atherosclerosis plaque in the coronary arteries of non-human primates, according to a study by researchers at Wake Forest Baptist Medical Center. Coronary artery atherosclerosis is the primary cause of heart attacks.

Gene testing could find those who would benefit most from statins

NHS. UK: "Patients with the highest genetic risk of suffering a heart attack benefit the most from cholesterol-lowering statin drugs," The Guardian reports. Statins are drugs that lower cholesterol and can help reduce the risk of coronary heart disease (CHD) developing – the leading cause of death both in the UK and worldwide.

Transmyocardial laser revascularization compared to medical therapy for refractory angina

Cochrane: This review examines the effectiveness and safety of a surgical intervention using a laser device directly on the heart surface for patients suffering from angina for whom other interventions are not suitable. This is an updated version of the original review published in 2009.

Coronary heart disease leading cause of death for men aged 50 and over in 2013

British Heart Foundation: Coronary heart disease (CHD) was the leading cause of death for men aged 50 and over in 2013, according to latest figures. More than 36,000 deaths for men aged 50 and over were attributed to CHD in 2013.

Figures published by the Office for National Statistics show that CHD is still the leading cause of death in England and Wales.

Older adults with limited mobility may lessen heart problems with activity

American Heart Association: Older adults with limited mobility may lower their risk of heart attack and coronary death for every minute of physical activity, according to research in the Journal of the American Heart Association.

Discovery of a personalized therapy for cardiovascular disease

Montreal University. Canada: Researchers at the Montreal Heart Institute announced today results showing that patients with cardiovascular disease and the appropriate genetic background benefit greatly from the new medication dalcetrapib, with a reduction of 39% in combined clinical outcomes including heart attacks, strokes, unstable angina, coronary revascularizations and cardiovascular deaths.

ACE inhibitors

Mayo Clinic. US: Angiotensin-converting enzyme (ACE) inhibitors help relax blood vessels. ACE inhibitors prevent an enzyme in your body from producing angiotensin II, a substance in your body that affects your cardiovascular system by narrowing your blood vessels and releasing hormones that can raise your blood pressure. This narrowing can cause high blood pressure and force your heart to work harder.

Coronary Heart Disease

anterior myocardial infarct. Radiopaedia

Authors: Børge G. Nordestgaard and al. Herlev Hospital, Copenhagen University Hospital, Copenhagen, Denmark PLos Medicine 2012-05-01

Ischemic heart disease (IHD; also known as coronary heart disease) is the leading cause of death among adults in developed countries. In the US alone, IHD kills nearly half a million people every year. With age, fatty deposits (atherosclerotic plaques) build up in the walls of the coronary arteries, the blood vessels that supply the heart with oxygen and nutrients. The resultant reduction in the heart's blood supply causes shortness of breath, angina (chest pains that are usually relieved by rest), and potentially fatal heart attacks (myocardial infarctions). Risk factors for IHD include smoking, high blood pressure (hypertension), abnormal amounts of cholesterol and other fat in the blood (dyslipidemia), type 2 diabetes, and being overweight or obese (having excess body fat). Treatments for IHD include lifestyle changes (for example, losing weight) and medications that lower blood pressure and blood cholesterol levels. The narrowed arteries can also be widened using a device called a stent or surgically bypassed.

Heart attack

Author : Edward J McNulty Kaiser Permanente San Francisco Medical Center

2008-11-06

Heart Attack : Background, Diagnosis and Treatment

Heart attacks are a leading killer in both developed and developing nations. They are caused when part of the heart does not receive enough blood, usually because of a blockage in a coronary artery. This knol explains what is meant by a heart attack, how they are caused, and how this condition is diagnosed.

What is a heart attack?

     A heart attack occurs when there is a blockage of blood flow to the heart muscle, causing an area of the heart muscle to die.  This most commonly occurs due to a blockage of a coronary artery (see “coronary arteries”).  If there is a complete blockage in one of the three main coronary arteries, a large heart attack may occur, during which the part of the heart muscle fed by the artery dies.   If the blockage is not complete, bits of blood clot can travel downstream and clog smaller arteries, causing a smaller heart attack.  Both large and small heart attacks are serious and potentially fatal, and both require urgent attention.  Heart attacks are also called “myocardial infarctions” and often abbreviated as “MIs.”

How common are heart attacks?

     It is estimated that one half of men in the US and one third of women will develop angina (pain from a blocked artery in the heart) or suffer a heart attack in their lifetimes (2).   Fatal complications of coronary artery disease (primarily heart attack) are the most common cause of death in the United States, killing approximately half a million people per year.  There are approximately 8 million heart attacks per year in the United States (3).  While heart attacks have long been a leading killer in most developed countries, they have rapidly grown as a problem in developing nations and are now the leading cause of death in lower income countries (4).

Types of Heart Attacks

     There are two main types of heart attacks.  The large heart attacks that result when one of the main coronary arteries become blocked usually cause distinct changes on an electrocardiogram (“see Diagnosis of Heart Attack – ECG”) and are often referred to as “ST Elevation myocardial infarctions.”  (see Figure 1) Smaller heart attacks caused by bits of blood clot traveling downstream into smaller arteries usually cause different findings on an electrocardiogram and are called “non-ST Elevation myocardial infarctions.”

Figure 1.  ECG of an “ST segment elevation myocardial infarction”

What causes heart attacks?

the role of plaque

     The most common disease that affects coronary arteries and leads to heart attacks is “atherosclerosis” (literally meaning hardening of arteries due to plaque formation).  In atherosclerosis, plaque (consisting of cholesterol and other materials) is deposited within the wall of the arteries.  Not only does this plaque cause the arteries to become hardened, but the insides become narrowed.  Once plaque has grown large enough, blockage to the flow of blood may occur.  This can obstruct the flow of blood if the plaque becomes large enough (see Figure 2a), resulting in what is commonly referred to as a “blockage” or “clogged artery,” similar to a kitchen pipe becoming clogged with debris that prevents water from flowing through it.  If there is obstruction to flow through a coronary artery, there may not be enough blood for the heart muscle beyond the obstruction.   As noted above, this becomes a heart attack when the obstruction is complete and the heart muscle fed by the artery dies.

Figure 2.

   

     Over the past few decades a greater understanding of the role of plaque in causing heart attacks has emerged.   Sometimes the plaque can rupture into the inside of the artery, resulting in a blood clot forming on the plaque that completely obstructs the flow of blood and causes a heart attack (see Figure 2b).  While plaques associated with severe blockages can rupture and lead to heart attacks, there are often many less severe plaques scattered throughout the arteries, often not associated with severe narrowing, that may also rupture  and lead to obstruction of blood and also cause heart attacks (see Figure 2c).

Traditional Risk Factors
(See Table 1)

Table 1.  Traditional Risk Factors for Heart Attack

Age

Male gender

Tobacco Use

High Blood Pressure

Diabetes

High LDL (“bad”) cholesterol

Low HDL (“good”) cholesterol

Family History of early heart attack

     "Risk factors" are things that make it more likely that someone will develop a certain condition.  Over the past half a century, there have been tremendous efforts in identifying the risk factors for heart attacks.  Most patients with heart attacks have high blood pressure, abnormal cholesterol, diabetes, or a history of tobacco use (5,6).  These risk factors – along with older age, male gender, and a family history of premature coronary artery disease – comprise the “traditional” risk factors for having a heart attack and are discussed below.

Gender
     Heart attacks are more common in men, but become more common in women following menopause.  One explanation for this has been that the female hormone “estrogen” provides some protection from coronary disease.  However, taking estrogen after menopause does not appear to protect women from heart attacks and may in fact increase the risk (7).

Age
     Since plaque in coronary arteries forms over time, heart attacks are more common later in life.

High blood pressure
     The higher the systolic blood pressure (the higher of the two blood pressure readings) and the higher the diastolic blood pressure (the lower of the two readings) the greater the risk of having a heart attack.  Guidelines for treatment usually define elevated systolic blood pressure as above 140 mm Hg, and elevated diastolic blood pressure as above 90 mm Hg.  Studies including hundreds of thousands of people have shown that lower blood pressure (systolic and diastolic) indicates a reduced risk of suffering a heart attack (8,9).  The risk of dying from a heart attack is reduced by roughly half for every 20 mm Hg decrease in the systolic blood pressure or 10 mm Hg decrease in diastolic blood pressure (10).

Tobacco use 
     Tobacco use is considered the strongest potentially “modifiable” risk factor for having a heart attack (a modifiable risk factor is one that can be changed, unlike age or gender).  Cigarette smoking increases ones risk of dying from complications of coronary artery disease, primarily heart attack, by two to three times (11).  Furthermore, an estimated 35,000 nonsmokers die in the United States from complications of coronary artery disease each year as a result of exposure to “second hand” tobacco smoke (12).

Link to CDC tobacco factsheet:
http://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/tobacco_related_mortality/

Cholesterol

     The higher one’s total cholesterol level is, the greater the risk of having a heart attack (13).  When total cholesterol is greater than 200 mg/dl it is considered elevated.  There are many types of cholesterol, and modern guidelines rely upon looking at the various components of cholesterol. The higher one’s low density lipoprotein (LDL) cholesterol (often referred to as “bad” cholesterol) the greater the chance of developing plaque in the coronary arteries and dying as a result of a heart attack.  On the other hand, high density lipoprotein (HDL) cholesterol (often referred to as “good” cholesterol”) seems to protect individuals from heart attacks.  HDL levels tend to be higher in women than in men.  A low HDL cholesterol level (less than 40 mg/dl) therefore is not a good thing and is considered a risk factor for heart attack in current guidelines.  An HDL cholesterol of greater than 60 mg/dl is considered a “negative” risk factor; that is, having a high HDL level protects one from having a heart attack. Triglycerides are another type of cholesterol that appear to increase the risk of heart attack, especially in women.  Normal triglyceride levels are less than 150 mg/dl.  Whether other types of cholesterol, as well as ratios of various components, are more useful to measure is a subject of much current research and debate.
   
Diabetes

     Diabetes is considered a “coronary artery disease equivalent,” meaning that adults with diabetes have similar risks of dying from complications of coronary artery disease, primarily heart attacks, as do individuals with established coronary artery disease.

Family History of Premature Coronary Artery Disease

     Heart attacks are common, especially as ones get older, so the majority of individuals have a blood relative who has had a heart attack.  Early or premature coronary artery disease (including heart attack) refers to women having complications of coronary artery disease (a heart attack, angina, or a coronary procedure such as an angioplasty or bypass surgery) before the age of 65 or a man before the age of 55.  A “family history of premature coronary artery disease” means that one has a first degree relative (mother, father, brother or sister) with premature coronary artery disease, and this increases one’s risk for developing a heart attack (14).

Traditional Risk Scores

     The risk factors above are considered “traditional” risk factors.  Much of the work in identifying these factors came from following the population of Framingham, Massachusetts for many years (14).  A limitation of this work was that most of the population studied was Caucasian.  Subsequent studies have confirmed the role of these same risk factors in more diverse populations (15,16).  There are many “risk scores” that can be used to calculate an individual’s risk of having a heart attack or dying from complications of coronary artery disease.  One commonly used calculator is the Framingham Risk Calculator.

Link to Framingham risk calculator:   http://hp2010.nhlbihin.net/atpiii/calculator.asp?usertype=pub
Other Risk Factors for Heart Attack

     While there is abundant evidence linking the above risk factors to coronary artery disease, many (up to 20%) of individuals can develop complications of coronary artery disease, including heart attacks, without any of the identified traditional risk factors.  Therefore there has been much effort at identifying other risk factors for coronary artery disease and heart attacks.

Peripheral Artery Disease

     As with diabetes, individuals with peripheral artery disease (severe plaque in arteries in the neck or extremities) or abdominal aortic aneurysms have similar risks of developing complications from coronary artery disease as do individuals with established coronary artery disease, and therefore are treated as if they have coronary artery disease.

Physical inactivity/lack of exercise 

     Physical activity appears to reduce the risk of heart attack and death from coronary artery disease.  Conversely, physical inactivity and poor conditioning increases the risk of these complications (16).  Among its beneficial effects, exercise reduces weight (and the risk of developing diabetes) and blood pressure – and improves cholesterol.
Obesity 
     Obesity increases blood pressure, lowers “good” (HDL) cholesterol, raises “bad” (LDL) cholesterol and triglycerides, and increases the risks of diabetes.  In other words, obesity causes many of the other known risk factors for coronary artery disease and heart attack.  Obesity also appears to increase the risk of suffering complications of coronary artery disease in and of itself, independent of these other risk factors (17).  Furthermore, the location of adipose tissue (fat) appears to be important, with having abdominal obesity (fat in the truck or “belly”) being worse than having fat more spread out through the body.  Obesity is usually defined as having a body mass index or BMI of greater than 30.
Link to BMI calculator:
http://www.nhlbisupport.com/bmi/

The metabolic syndrome

     The metabolic syndrome refers to individuals who have three of the following: abdominal obesity, elevated fasting blood sugar (a precursor to diabetes), high blood pressure, low good (HDL) cholesterol, and elevated triglycerides.  Whether this syndrome confers a risk for coronary artery disease and heart attack beyond the additive risks of the individual risk factors is a subject of controversy and current research.

Diet

     Coronary artery disease and heart attacks are more common in countries with diets higher in animal fat and processed sugar (so called “Industrial” or “Western Diets”) (18).  Even among western countries there is considerable variation in the rates of coronary artery disease and heart attack from country to country.  In general, countries with a very high intake of animal fat have correspondingly high rates of coronary artery disease and heart attacks.  Additional evidence for the role of diet in developing coronary artery disease comes from studying individuals migrating from areas where coronary artery disease is uncommon to areas where it is very common.  For example, studies of Japanese immigrants revealed dramatic increases in the rates of coronary artery disease once individuals moved to western countries and adopted western diets.  Finally, as countries develop and adopt western diets, the incidence of coronary artery disease and heart attacks increases.

     While the evidence linking diet to coronary artery disease and heart attacks is compelling, there is also much about this relationship that is poorly understood.  Some fats appear to be harmful (saturated and “trans” fatty acids) while others seem to be protective (polyunsaturated and monounsaturated fats).  Studies have shown lower rates of coronary artery disease and heart attack in countries with diets rich in omega-3 fatty acids, part of the so called “Mediterranean Diet” (19).

Alcohol use

     Moderate alcohol intake (one drink per day for women and one to two drinks per day for men) appears to be protective against death from coronary artery disease and heart attack (16).  While some studies have suggested that substances in red wine could account for this protective effect, it appears that any alcohol intake is protective.  It should be noted that this finding refers to individuals who have established moderate patterns of alcohol intake, not individuals who begin drinking to prevent the development of coronary artery disease. At least part of the beneficial effect of alcohol intake is due to increasing levels of good cholesterol.

Stress and Depression

     Anxiety, depression, and having “type A” personality have all been shown to increase the risk of developing complications of coronary artery disease and heart attack (20).

Drugs

     Certain medications and illicit drugs can also cause heart attacks, including cocaine and methamphetamine.

What are the symptoms of a heart attack?

     The typical symptom of a heart attack is chest discomfort,  usually described as a sensation of pain or pressure over the middle or left side of the chest.  However many people having heart attacks have different symptoms such as neck pain, arm or shoulder pain (usually but not always on the left side), or pain in the upper abdomen (above the umbilicus or "belly button").  Other less "typical" symptoms that patients having heart attacks experience include nausea or a feeling of fullness in the upper abdomen.  In addition to these symptoms, people having heart attacks also have other "associated" symptoms, such as sweating and a feeling of breathlessness.  Typical symptoms occur in only about a half of individuals with heart attack, and occur more often in men than women.  Some people experience little in the way of symptoms despite having major heart attacks, especially those with diabetes. 
     Often people having heart attacks feel tired with less energy in the days leading up to heart attacks.  Sometimes patients with angina develop worsening symptoms in the days leading up to a heart attack.  If you or someone you know thinks that they may be having a heart attack, it is vital that they seek medical attention right way (in other words, call 911).  The sooner heart attack victims get treated, the more lives are saved and the more heart muscle is saved.

Complications of heart attacks

     The most dreaded complication of heart attacks is death, and up to one half of patients experiencing heart attacks die before they can receive medical attention.  Those surviving until they reach the hospital do better, but many still die.  There are two main ways that heart attacks can result in death, either through causing fatal irregular heart beats or by causing so much of the heart to die that the patient goes into “shock” and dies.  Earlier recognition and treatment can reduce these complications and improve survival.  Even if an individual survives the heart attack, the heart can be left weakened and “congestive heart failure” can result.

How is a Heart Attack Diagnosed?

1.  Electrocardiogram (“ECG”)

     If a heart attack is suspected, an electrocardiogram (ECG) is performed.  This test entails placing electrodes (simple adhesive strips) on the patient to measure the electrical activity of the heart, and can be useful in detecting signs of an ongoing or imminent heart attack as well as a prior heart attack (see figure 1).  It is quick, easy to perform and relatively inexpensive and is therefore useful as an initial tool in the diagnosis of suspected heart attack.  However, individuals with a normal ECG can still have a heart attack.

2.  Blood tests

     Certain substances are released into the blood in patients having a heart attack and can be detected by blood tests.  These tests, especially measurement of the creatine phosphokinase (“CPK”) and troponin, are useful in determining if an individual is having a heart attack.

3.  Coronary Angiography (“Cardiac Catheterization”)

     Currently, the most accurate method to detect blockages in the coronary arteries is invasive angiography.  This is an invasive test, because it requires temporarily placing objects into the body and is performed in a facility called a catheterization laboratory.   It is usually recommended in patients with a suspected major heart attack (an “ST Segment Elevation MI) and in many patients with smaller heart attacks.  It is performed by placing a hollow tube (called a sheath) into an artery in the groin or wrist and then threading small “catheters” (hollow, plastic tubes 2-3 mm in diameter) through the arteries to the coronary arteries.  This is performed using X-ray guidance, so the procedure does require exposure to radiation.  Once the catheters are placed into the beginnings of the coronary arteries, a substance called “contrast” is injected into the arteries while X-ray movies are taken.  The contrast contains iodine so that X-rays will not penetrate it; therefore arteries with contrast inside appear dark on the X-ray picture.  In this way a picture of the inside of the coronary arteries is obtained, usually from multiple positions, and blockages detected. (See figure 3). 

Figure 3.  Angiography

Blockages can sometimes be treated at the same time with angioplasty and stents (see figure 4).


Figure 4.  Angiogram showing complete blockage in right coronary artery, before (top) and after (bottom) treatment with a stent.  Arrow in top panel points to blood clot at blockage in the artery.

Treatment of heart attacks:  “Time is muscle”

     It cannot be overemphasized how important prompt treatment is in reducing the risk of death in heart attacks.  Even if it is not possible to perform an angiogram right away, clot dissolving medicines can be administered which are also effective in treating heart attacks.  The more time that elapses when there is a complete blockage in an artery in the heart, the less likely it becomes that the heart muscle can be saved and the more likely fatal complications become.

     Initial treatments for heart attack include aspirin, oxygen, nitroglycerin and sometimes morphine.  This should be done by experienced medical personnel and in a setting where the patient can be monitored.  Other medicines that are given early in heart attacks to certain patients are beta blockers and other blood thinning medicines including aspirin. 

     For larger heart attacks, or so called "ST segment elevation heart attacks," patients are taken as quickly as possible to a cardiac catheterization laboratory for a "coronary angiogram."  If a completely blocked or seriously blocked artery is found, it can usually be opened with a balloon and a stent.  Sometimes the blockages are in locations that require open heart bypass surgery.  If patients cannot be taken quickly for a cardiac catheterization, then powerful clot dissolving medicines called "thrombolytics" are given.

     For smaller heart attacks, patients are also treated with medications including beta blockers and blood thinning medications including aspirin.  Depending on how serious the heart attack is, patients may have a stress test or be sent for a coronary angiogram where blockages can be treated with balloons and stents.

     During the recovery from a heart attack, patients are usually treated with cholesterol lowering medications (especially a type called "statins") and also given medications including aspirin (or other similar blood thinning medicines), beta blockers, and ACE inhibitors.  Also important is adopting a healthy diet and lifestyle.

Other Links

National Heart Lung and Blood Institute

American Heart Association

References
1. Roger VL, Weston SA, Killian JM et al  Time Trends in the Prevalence of Atherosclerosis: A Population-based Autopsy Study Am Journal Med 2001 110:267-273.

2. Jones DM, Larson MG, Beiser A Levy D , Lifetime Risk of Developing Coronary Heart Disease Lancet 1999; 353:89-92.

3.  American Heart Association/American Stroke Association Heart Disease and Stroke Statistics, 2008.

4.  World Heath Organization Global Burden of Disease Statistics 2002 (http://www.who.int/healthinfo/bodestimates/en/index.html).
     
5.  Greenland, P, Knoll, MD, Stamler, J, et al. Major risk factors as antecedents of fatal and nonfatal coronary heart disease events. JAMA 2003; 290:891.

6.  Khot UN, Khot MB, Bajzer CT, Sapp SK et al Prevalence of Conventional Risk Factors in Patients With Coronary Heart Disease JAMA 2003; 290:891.

7.  NIH Women’s Health Initiative (www.nhlbi.nih.gov/whi/)

8.  S. MacMahon, R. Peto and J. Cutler et al., Blood pressure, stroke and coronary heart disease: Part I. Prolonged differences in blood pressure: Prospective observational studies corrected for the regression dilution bias, Lancet 335 (1990), pp. 765–774.

9.  W.B. Kannel, M.J. Schwartz and P.M. McNamara, Blood pressure and the risk of coronary heart disease: The Framingham study, Crit Rev Dis Chest 56 (1969), p. 43.

10.  Prospective Studies Collaberation Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies The Lancet 2002 360:1903-1913.

11.  Centers for Disease Control and Prevention, Tobacco-related Mortality Fact Sheet.  Sept 2006.  www.cdc.gov/tobacco/factsheets/Tobacco_Related_Mortality_factsheet.htm

12.  Annual Smoking-Attributable Mortality, Years of Potential Life Lost, and Productivity Losses – United States, 1997-2001, Morbidity and Mortality Weekly Report 2005;54:625-628.

13.  Third Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (ATP III Final Report) National Heart Lung and Blood Institute.
www.nhlbi.nih.gov/guidelines/cholesterol/atp3_rpt.htm

14.  Anderson KM, Odell PM, Wilson PWF and Kannel WB Cardiovascular disease risk profiles, Am Heart J 121 (1991), pp. 293–298.

 15.  Ramachandran SV, Sullivan LM, Wilson PWF, Sempos CT, Sundstrom J et al Relative Importance of Borderline and Elevated Levels of Coronary Heart Disease Risk Factors Annals Int Med 2005;142:393-402.

16.  Yusuf S, Hawken S, Ounpuu, Dans T, Avezum A et al  Effect of Potentially Modifiable Risk Factors Associated with Myocardial Infarction in 52 countries (the INTERHEART Study): a case control study.  Lancet 2004 364:937-52.

17.  Yan et al Midlife BMI and Hosp and Mortality in Older Age JAMA 2006; 295:190-198.

18.  Yusuf S, Reddy S, Ounpuu and S Anand, Global burden of cardiovascular diseases: part I: general considerations, the epidemiologic transition, risk factors, and impact of urbanization, Circulation 104 (2001): 2746–2753.

19.  Anderson CAM and Appel LJ Dietary Modification and CVD Prevention: A Matter of Fat JAMA 2006; 295(6): 693 – 695


20.  Rosengren A, Hawken S and Ôunpuu S et al., Association of psychosocial risk factors with risk of acute myocardial infarction in 11 119 cases and 13 648 controls from 52 countries (the INTERHEART study): case-control study, Lancet 364 (2004), pp. 953–962

Coronary artery disease background diagnosis

Author : Edward J McNulty Kaiser Permanente San Francisco Medical Center

2008-11-06

Coronary Artery Disease : Background and Diagnosis

This article explains what is meant by coronary artery disease, the major complications that can result (including heart attacks), what is known about the causes of the disease, and finally, how the disease is diagnosed.

Introduction

The term “coronary artery disease” most commonly refers to the build up of plaque inside the arteries that provide the heart with blood. This is something that is very common, especially as people get older. Coronary artery disease can cause complications, including angina (discomfort commonly felt in the chest or neck), heart attacks, potentially fatal irregular heart beats, and a weakened or failing heart. This Knol explains what is meant by coronary artery disease, the major complications that can result (including heart attacks), what is known about the causes of the disease, and finally, how the disease is diagnosed.

What are coronary arteries?

The heart is a muscle that pumps blood to the lungs and to the rest of the body. All muscles, including the heart, require a supply of blood in order to function. The blood carries nutrients and oxygen to the muscle, and removes the leftover “waste products.” Even th

ough the heart is filled with blood, the heart muscle does not get oxygen and nutrients directly from the blood coursing through it.  Instead, the thick walls of the heart muscle require their own blood supply from “arteries.”  Arteries are the vessels that carry blood from the heart to the rest of the body.  They are hollow tubes that branch into smaller and smaller vessels, much as water mains branch to supply a city with water.  Coronary arteries are the blood vessels that carry blood to the heart muscle itself.  They are on the outside of the heart and have branches that carry blood deeper into the heart muscle, supplying it with blood from the “outside in” (see figure 1).

Figure 1.  Coronary Arteries

 

Coronary Artery Anatomy

     Most people are born with three coronary arteries (See Figure 2).  These arteries arise from the main artery carrying blood out of the heart, the aorta.  Two of the coronary arteries, the left anterior descending and left circumflex, usually arise from a common trunk referred to as the left main coronary artery.  The third coronary artery, the right coronary artery, usually arises separately. 

Figure 2.  Coronary Arteries, anatomy

What is Coronary Artery Disease?

     Coronary arteries can be affected by many diseases.  By far the most common disease to affect the coronary arteries is atherosclerosis (literally meaning hardening of arteries due to plaque formation).  In atherosclerosis, “plaque” (consisting of cholesterol and other materials) is deposited within the wall of the arteries.  Atherosclerosis is a disease that can affect many arteries in the body, not just the coronary arteries (see Figure 3). 

Figure 3.  Severe plaque in the aorta

Atherosclerosis is a process that appears to begin even before we are born, with the precursors to plaque (“fatty streaks”) being evident in the largest artery (the aorta) in fetuses.  Actual plaque can be detected in the arteries of teenagers.  Plaque formation is also a process may occur gradually, or progress more rapidly, in fits and starts.  Not only does this plaque cause the arteries to become hardened, but the insides of the vessels become narrowed.  Once plaque has grown large enough, blockage to the flow of blood may occur.  This can completely obstruct the flow of blood if the plaque becomes large enough (see Figure 4a), resulting in what is commonly referred to as a “blockage” or “clogged artery,” similar to a kitchen pipe becoming clogged with debris that prevents water from flowing through it.  If there is obstruction to the flow of blood through a coronary artery, there may not be sufficient blood reaching the heart muscle beyond the obstruction.  This leads to a situation referred to as “ischemia.”  On a very basic level ischemia means there is not enough supply of blood to meet the demand from the heart muscle.  If the obstruction is complete, then the heart muscle fed by the artery can die, a process called a myocardial infarction (“MI”) and more commonly referred to as a heart attack.  Both ischemia and infarction can lead to discomfort or “angina” (see “symptoms of coronary artery disease”), difficulty breathing, a weakened heart muscle or heart failure (see “Heart Failure”), and cause irregular heart beats (“arrhythmias”) which can be fatal. 

Figure 4. 

    
     The consequences of the blockages depend not only on how severe they are, but also on how quickly they form.   Blockages that form gradually may result in a condition called “stable angina” (see “symptoms of coronary artery disease”).  Blockages that develop or worsen abruptly may result in a more dangerous condition called  “unstable angina,” or may cause a heart attack.

How Does Plaque Lead to a Heart Attack?
     Over the past few decades a greater understanding of the role of plaque in causing heart attacks has emerged.   Sometimes the plaque can “rupture” into the inside of the artery, resulting in a blood clot forming on the plaque that completely obstructs the flow of blood and causes a “heart attack” (see Figure 4b).  While plaques associated with severe blockages can rupture and lead to heart attacks, there are often many less severe plaques scattered throughout the arteries.   Although these are often not associated with severe narrowing, they are also prone to rupture (see Figure 4c). 


Figure 5.  Microscopic cross section of atherosclerotic plaque within a coronary artery

Other Diseases Affecting Coronary Arteries

     While atherosclerosis is the most common disease to affect coronary arteries, other diseases can affect the coronary arteries and interfere with the normal flow of blood.  In some individuals the arteries have a tendency to narrow abruptly, or “spasm,” and this can interfere with blood flow much like obstructing plaque.  Sometimes the lining on the inside of the coronary artery (the “endothelium”) can become damaged.  This is especially common in smokers.  Blood clots can form on this damaged surface, which in turn may lead to obstruction of flow and a heart attack (see “heart attack”).  Other, much less common conditions, include congenital abnormalities (abnormalities in number and location of coronary arteries that patients are born with), abnormal communications with other blood vessels (“fistulas”), aneurysm formation, and damage to the arteries as a consequence of radiation or other diseases affecting blood vessels throughout the body.  All of these conditions can lead to obstruction of the flow of blood down the coronary artery, either by narrowing the space inside, causing a blood clot to form, or both.

How Common is Coronary Artery Disease?

    
    Since plaque forms over time it is more common later in life.  Autopsy data from Olmstead County in Minnesota revealed that 27% of patients aged 20-59 years had significant plaque build up in their coronary arteries.   Among individuals aged 60 years and older, over half had significant plaque (1).  It is important to note that many individuals have plaque in their coronary arteries but never experience symptoms or clinical manifestations of the disease.

What problems can plaque in coronary arteries cause?  (Clinical Consequences of Coronary Artery Disease)

     It is estimated that one half of men in the US and one third of women will develop angina or suffer a heart attack in their lifetimes (2). In round numbers, this amounts to approximately 8 million heart attacks per year in the United States, and an additional 9 million people who will suffer from angina (3).  Fatal complications of coronary artery disease (primarily heart attack) are the most common cause of death in the United States, killing approximately half a million people per year. While coronary artery disease has long been a leading killer in most developed countries, it has rapidly grown as a problem in developing nations and is now the leading cause of death in lower income countries (4).  The rise in heart disease seems to be due developing countries adopting diets higher in animal fat, increasing use of tobacco as well improved treatment of other causes of death in these countries (i.e. improved treatment of infections means people are now dying of heart disease instead).

What Causes Coronary Artery Disease?  “Traditional” Risk Factors for Developing Coronary Artery Disease

See Table 1.  Traditional Risk Factors for CAD

Table 1.  “Traditional Risk Factors” For Coronary Artery Disease

Age

Male Gender

Diabetes

High Blood Pressure

Tobacco Use

High LDL (“Bad”) Cholesterol

Low HDL (“Good”) Cholesterol

Family History of Premature Coronary Artery Disease

     Risk factors are things that make it more likely that someone will develop a certain condition.  Over the past half a century, there have been tremendous research efforts aimed at identifying the risk factors for developing complications of coronary artery disease.  Most patients with coronary artery disease have high blood pressure, abnormal cholesterol, diabetes, or a history of tobacco use (5,6).  These risk factors, along with older age, male gender, and a family history of premature coronary artery disease comprise the “traditional” risk factors for developing complications of coronary artery disease, and are each discussed below.

Gender
     Coronary artery disease is more common in men, but becomes common in women following menopause.  One explanation for this has been that the female hormone estrogen provides some protection from coronary disease.  However, taking estrogen after menopause does not appear to protect women from coronary disease and may in fact increase the risk (7).

Age
     Since plaque in coronary arteries forms over time it is more common later in life.  Autopsy data from Olmstead County in Minnesota revealed that 27% of patients aged 20-59 years had significant plaque build up in their coronary arteries disease.   Among individuals aged 60 years and older, over half had significant plaque (1). 

High Blood pressure
     The higher the systolic blood pressure (the higher of the two blood pressure readings) and the higher the diastolic blood pressure (the lower of the two readings) the greater the risk of death from coronary artery disease.  Guidelines for treatment usually define elevated systolic blood pressure as above 140 mm Hg, and elevated diastolic blood pressure as above 90 mm Hg.  Studies including literally hundreds of thousands of people have shown that the risk of suffering a heart attack or developing other complications from coronary artery disease decrease the lower one’s blood pressure (systolic and diastolic) is (8,9).  The risk of dying from coronary artery disease is reduced by roughly half for every 20 mm Hg decrease in the systolic blood pressure or 10 mm Hg decrease in diastolic blood pressure (10).

Tobacco use 
     Tobacco use is considered the strongest potentially “modifiable” risk factor for coronary artery disease (a modifiable risk factor is one that can be changed, unlike one’s age or gender).  Cigarette smoking increases the risk of dying from complications of coronary artery disease by two to three times (11).  Furthermore, an estimated 35,000 nonsmokers die yearly in the United States from complications of coronary artery disease as a result of exposure to “second hand” tobacco smoke (12).

Link to CDC tobacco factsheet  www.cdc.gov/tobacco/factsheets/Tobacco_Related_Mortality_factsheet.htm

Cholesterol

     The higher one’s total cholesterol level, the greater the risk of dying or developing other complications from coronary artery disease (13).  Total cholesterol greater than 200 mg/dl is considered elevated.  There are many types of cholesterol, and modern guidelines establish goal levels according to the various components of cholesterol. The higher the “Low Density Lipoprotein (LDL) cholesterol” (often referred to as “bad” cholesterol), the greater the chance of developing plaque in the coronary arteries and dying as a result of complications from coronary artery disease.  On the other hand, “High Density Lipoprotein (HDL) cholesterol” (often referred to as “good” cholesterol”) seems to protect individuals from coronary artery disease.  HDL levels tend to be higher in women than in men.  A low HDL cholesterol level (< 40 mg/dl) therefore, is not a good thing, and is considered a risk factor for developing complications of coronary artery disease according to current guidelines.  An HDL cholesterol of  > 60 mg/dl is considered a “negative” risk factor; that is, having a high HDL level protects one from coronary artery disease. Triglycerides are another type of cholesterol that appear to increase the risk of coronary artery disease, especially in women.  Normal triglyceride levels are < 150 mg/dl.  Whether other types of cholesterol, as well as ratios of various components, are more accurate at measuring risk is a subject of much current research and debate.

Diabetes

     Diabetes is considered a “coronary artery disease equivalent.”  This means that adults with diabetes carry a risk of developing either symptoms from coronary artery disease or dying from complications of coronary artery disease that is as high as individuals with established coronary artery disease.  They are therefore treated as if they have coronary artery disease in terms of recommendations for diet, lifestyle and medications.

Family History of Premature Coronary Artery Disease

     Coronary artery disease is common, especially as one gets older, so the majority of individuals with coronary artery disease will have a blood relative who also developed coronary artery disease.  Early or premature coronary artery disease refers to women having complications of coronary artery disease (a heart attack, angina, or a coronary procedure such as an angioplasty or bypass surgery) before the age of 65 or a man before the age of 55.  A “family history of premature coronary artery disease” means that one has a first degree relative (mother, father, brother, or sister) with premature coronary artery disease, and this increases ones risk for developing coronary artery disease (14).


Traditional Risk Scores - Combining Risk Factors

     These risk factors are considered “traditional” risk factors.  Much of the work in identifying these factors came from following the population of Framingham, Massachusetts for many years (14).  A limitation of this work was that most of the population studied was Caucasian.  Subsequent studies have confirmed the role of these same risk factors in more diverse populations (15,16).  There are many “risk scores” that can be used to calculate an individual’s risk of having a heart attack or dying from complications of coronary artery disease.  One commonly used calculator is the Framingham Risk Calculator:

Link to Framingham risk calculator http://hp2010.nhlbihin.net/atpiii/calculator.asp?usertype=pubFramingham Risk Calculator

Other Risk Factors for Coronary Artery Disease

     While there is abundant evidence linking the above risk factors to coronary artery disease, many (up to 20%) of individuals can develop complications of coronary artery disease without any of the identified “traditional risk factors.” Much effort has been devoted to identifying other risk factors for coronary artery disease.

Peripheral Artery Disease

     As with diabetes, individuals with peripheral artery disease (severe plaque in arteries in the neck or extremities), or abdominal aortic aneurysms have similar risks of developing complications from coronary artery disease as do individuals with established coronary artery disease, and therefore are treated as if they have coronary artery disease.
 
Physical inactivity/lack of exercise 

     Physical activity appears to reduce the risk of heart attack and death from coronary artery disease.  Conversely, physical inactivity and poor conditioning increases the risk of these complications (16).  Among its beneficial effects, exercise reduces weight (and the risk of developing diabetes), blood pressure, and improves cholesterol.

Obesity  

     Obesity increases blood pressure, lowers “good” (HDL) cholesterol, raises “bad” (LDL) cholesterol and triglycerides, and increases the risks of diabetes.  In other words, obesity causes many of the other known risk factors for coronary artery disease.  Obesity also appears to increase the risk of suffering complications of coronary artery disease in and of itself, "independent" of these other risk factors (17).  Furthermore, the location of adipose tissue (fat) appears to be important. Having abdominal obesity (fat in the truck or “belly”) is worse than having fat that is more spread out through the body.  Obesity is usually defined as having a “body mass index (BMI)” of > 30.

Link to BMI calculator:
http://www.nhlbisupport.com/bmi/

The "metabolic syndrome "

     The “metabolic syndrome” refers to individuals who have three of the following: abdominal obesity, elevated fasting blood sugar (a precursor to diabetes), high blood pressure, low good (HDL) cholesterol, or elevated triglycerides.  Whether this syndrome confers a risk for coronary artery disease beyond the additive risks of the individual risk factors is a subject of controversy and current research.

Diet

     Coronary artery disease is more common in countries with diets higher in animal fat and processed sugar (so called “Industrial” or “Western Diets”) (18).  Even among western countries there is considerable variation in the rates of coronary artery disease.  In general, countries with a very high intake of animal fat have correspondingly high rates of coronary artery disease.  Additional evidence for the role of diet in developing coronary artery disease comes from studying individuals migrating from areas where coronary artery disease is uncommon to areas where it is very common.  For example, studies of Japanese immigrants revealed dramatic increases in the rates of coronary artery disease once individuals moved to Western countries and adopted Western diets.  Finally, as countries develop and adopt “Western” diets, the incidence of coronary artery disease increases.

     While the evidence linking diet to coronary artery disease is compelling, there is also much about this relationship that is poorly understood.  Some fats appear to be harmful (saturated and “trans” fatty acids) while others seem to be protective (polyunsaturated and monounsaturated fats).  Studies have shown lower rates of coronary artery disease in countries with diets rich in omega-3 fatty acids (found especially in fish but also in other foods such as flax, walnuts and kiwi fruit), part of the so called “Mediterranean Diet” (19).

Alcohol use

     Moderate alcohol intake (1 drink per day for women and 1-2 drinks per day for men) appears to be protective against death from coronary artery disease (16).  While some studies have suggested that substances in red wine could account for this protective effect, it appears that any alcohol intake is protective.  It should be noted that this finding refers to individuals who have established moderate patterns of alcohol intake, not individuals who begin drinking to prevent the development of coronary artery disease. At least part of the beneficial effect of alcohol intake is due to increasing levels of good cholesterol.

Stress and Depression

     Anxiety, depression, and having “type A” personality have all been shown to increase the risk of developing complications of coronary artery disease (20).  The mechanisms behind these associations are not yet fully understood.

Drugs

Certain medications and illicit drugs can also lead to coronary artery disease, including cocaine and methamphetamine.

Symptoms of Coronary Artery Disease

     The blockages that cause coronary artery disease can worsen gradually over time, leading to so called “stable coronary artery disease,” or more progress more rapidly, leading to “unstable disease,” which includes heart attacks.  While both forms of the disease are serious, unstable disease and heart attack are much more likely to lead to serious complications, such as heart failure, or death.

     The hallmark symptom of coronary artery disease is “angina” (derived from the Latin word for choking).  “Typical” or “classic” angina is usually described as a sensation of pain or pressure over the middle or left side of the chest, neck or left arm, brought on by exertion or emotional distress and relieved by rest or nitroglycerin.  Typical symptoms occur in only about a half of individuals with coronary artery disease, and occur more often in men than women.  Other individuals can experience less typical symptoms (so called “atypical symptoms”) such as right shoulder pain, pain over the abdomen, nausea, or difficulty breathing to name just a few.  Other individuals experience little in the way of symptoms despite having severe or even complete blockages, especially those with diabetes.  Severe symptoms (for example, symptoms preventing one from walking up a flight of stairs or more than a few blocks), symptoms of recent onset, or symptoms occurring while at rest can be an indication of serious coronary artery disease, including a heart attack, and require emergent evaluation.

Diagnosis of Coronary Artery Disease

1.  Electrocardiogram (“ECG”)

     If unstable coronary artery disease or a heart attack is suspected, an electrocardiogram (ECG, sometimes called an “EKG”) is performed.  This test entails placing electrodes (attached with simple adhesive strips) on the patient to measure the electrical activity of the heart. These can be useful in detecting signs of an ongoing or imminent heart attack as well as a prior heart attack.  It is quick, easy to perform, and relatively inexpensive and is therefore useful as an initial tool in the diagnosis of coronary artery disease.  It is a test that involves electrodes onto the skin (usually with small adhesive "sticker electrodes") and then plugging them in to a small machine.  An electrical "picture" of the heart is obtained.  This is an easy, safe test that can be done just about anywhere.  However, individuals with a normal ECG can still have coronary artery disease or even a heart attack.

2.  Stress Test

     A stress test can be extremely useful in diagnosing coronary artery disease.  There are many different types of stress tests.  The simplest involves attaching a patient to an ECG (see ECG) and then having them exercise on a treadmill.  Other stress tests can use ultrasound or small doses of a radioactive chemical to actually see the heart during the "stress."  These tests can be performed in an outpatient office or in a hospital and usually take from one to four hours.  Stress tests can detect 70-90% of individuals with serious blockages in the coronary arteries, but are not for every patient.  Stress testing can also provide useful information regarding “prognosis” or the risk that an individual will suffer fatal complications from coronary artery disease.  (See "stress testing" knol - ADD LINK)

3.  Blood tests

     Certain substances are released into the blood in patients having a heart attack and can be detected.  These tests, especially measurement of the creatine phosphokinase (“CPK”) and troponins, are useful in determining if an individual is having a heart attack.

4.  Coronary Angiography (“Cardiac Catheterization”)

     Currently, the most accurate method to detect blockages in the coronary arteries is invasive angiography.   It is performed by placing a hollow tube (called a sheath) into an artery in the groin or wrist (while the patient is sedated) and then threading small “catheters” (hollow, plastic tubes 2-3 mm in diameter) through the arteries to the coronary arteries.  This is performed using X-ray guidance, so the procedure does require exposure to radiation.  Once the catheters are placed into the beginnings of the coronary arteries, a substance called “contrast” is injected into the arteries while X-ray movies are taken.  The contrast contains iodine so that X-rays will not penetrate it; therefore arteries with contrast inside appear dark on the X-ray picture.  In this way a picture of the inside of the coronary arteries is obtained, usually from multiple positions, and blockages detected. (See figure 6).  The procedure is performed in a facility called a catheterization laboratory.   It is usually recommended in patients with unstable disease or a suspected heart attack, or for patients with more severe stable angina.  There are other situations in which physicians may recommend this procedure.

Figure 6.  Angiography

Blockages can sometimes be treated at the same time with angioplasty and stents (see "treatment of CAD"  - ADD Link).


Figure 7.  Angiogram showing blockage in Left Anterior Descending Coronary Artery

     

     While angiography is a very good technique to detect blockages in the coronary artery, it does have some risks.  Because a tube must be placed into an artery in the arm or leg, there is a risk of bleeding or damage occurring to the artery that might require further treatment.  There is also a risk of damage to the kidneys or an allergic reaction occurring from the contrast medium (dye).  Fortunately, the risk of these complications is small, occurring in only 1-3% of patients.  The risk of stroke, heart attack and death is much smaller, and tends to occur in individuals who are generally more ill.

5.  CT Angiography and Electron Beam CT (Coronary Calcium Score)

     Recently, CT machines have become more powerful and are now capable of producing images of almost the same quality as invasive angiography.  While this procedure does not require the use of invasive catheters, it still requires the use of contrast medium and radiation.  Additionally, there is limited experience with this technique, and in certain patients (patients with fast or irregular heart beats) reliable images are difficult to obtain.  CT studies can also be used to detect calcium in the coronary arteries and determine a “calcium score.”  Patients with severe calcium in the coronary arteries are more likely to have serious blockages and appear to have an increased chance of suffering complications from coronary artery disease.

What is the outlook for patients with coronary artery disease? (Prognosis of coronary artery disease)

     The outlook for patients with coronary artery disease is variable and depends on the severity of the disease, whether the disease is “unstable” or “stable,” and other factors.  In general, patients with a stable disease have a more favorable prognosis than those with unstable disease.  Information obtained from the ECG, stress testing and angiography can be used guide decisions regarding treatment and to inform patients as to how likely they are to suffer further complications from the disease.

Other Links

National Heart Lung and Blood Institute - an excellent site with information for patients:

http://www.nhlbi.nih.gov/health/index.htm

American Heart Association "Heart Hub" site for patients:

http://www.americanheart.org/hearthub/index.htm

 References
1. Roger VL, Weston SA, Killian JM et al  Time Trends in the Prevalence of Atherosclerosis: A Population-based Autopsy Study Am Journal Med 2001 110:267-273.

2. Jones DM, Larson MG, Beiser A Levy D , Lifetime Risk of Developing Coronary Heart Disease Lancet 1999; 353:89-92.

3.  American Heart Association/American Stroke Association Heart Disease and Stroke Statistics, 2008.

4.  World Heath Organization Global Burden of Disease Statistics 2002 (http://www.who.int/healthinfo/bodestimates/en/index.html).
    
5.  Greenland, P, Knoll, MD, Stamler, J, et al. Major risk factors as antecedents of fatal and nonfatal coronary heart disease events. JAMA 2003; 290:891.

6.  Khot UN, Khot MB, Bajzer CT, Sapp SK et al Prevalence of Conventional Risk Factors in Patients With Coronary Heart Disease JAMA 2003; 290:891.

7.  Estrogen ref

8.  S. MacMahon, R. Peto and J. Cutler et al., Blood pressure, stroke and coronary heart disease: Part I. Prolonged differences in blood pressure: Prospective observational studies corrected for the regression dilution bias, Lancet 335 (1990), pp. 765–774.

9.  W.B. Kannel, M.J. Schwartz and P.M. McNamara, Blood pressure and the risk of coronary heart disease: The Framingham study, Crit Rev Dis Chest 56 (1969), p. 43.

10.  Prospective Studies Collaberation Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies The Lancet 2002 360:1903-1913.

11.  Centers for Disease Control and Prevention, Tobacco-related Mortality Fact Sheet.  Sept 2006.  www.cdc.gov/tobacco/factsheets/Tobacco_Related_Mortality_factsheet.htm

12.  Annual Smoking-Attributable Mortality, Years of Potential Life Lost, and Productivity Losses – United States, 1997-2001, Morbidity and Mortality Weekly Report 2005;54:625-628.

13.  Third Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (ATP III Final Report) National Heart Lung and Blood Institute.
www.nhlbi.nih.gov/guidelines/cholesterol/atp3_rpt.htm

14.  Anderson KM, Odell PM, Wilson PWF and Kannel WB Cardiovascular disease risk profiles, Am Heart J 121 (1991), pp. 293–298.

 15.  Ramachandran SV, Sullivan LM, Wilson PWF, Sempos CT, Sundstrom J et al Relative Importance of Borderline and Elevated Levels of Coronary Heart Disease Risk Factors Annals Int Med 2005;142:393-402.

16.  Yusuf S, Hawken S, Ounpuu, Dans T, Avezum A et al  Effect of Potentially Modifiable Risk Factors Associated with Myocardial Infarction in 52 countries (the INTERHEART Study): a case control study.  Lancet 2004 364:937-52.

17.  Yan et al Midlife BMI and Hosp and Mortality in Older Age JAMA 2006; 295:190-198.

18.  Yusuf S, Reddy S, Ounpuu and S Anand, Global burden of cardiovascular diseases: part I: general considerations, the epidemiologic transition, risk factors, and impact of urbanization, Circulation 104 (2001): 2746–2753.

19.  Anderson CAM and Appel LJ Dietary Modification and CVD Prevention: A Matter of Fat JAMA 2006; 295(6): 693 – 695


20.  Rosengren A, Hawken S and Ôunpuu S et al., Association of psychosocial risk factors with risk of acute myocardial infarction in 11 119 cases and 13 648 controls from 52 countries (the INTERHEART study): case-control study, Lancet 364 (2004), pp. 953–962