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Coronary artery disease

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Eighty percent of deaths due to coronary artery disease occur in persons older than 65 years of age, and coronary heart disease accounts for 50% of all deaths among persons older than 85 years of age.

The leading cause of death worldwide, contributing over 7.3 million deaths annually.

All forms of coronary heart disease are much less-common in the Third World, as its risk factors are much more common in Western and Westernized countries; suggesting it is a disease of affluence.

One of every six deaths in the United States is caused by CAD.

Coronary artery disease affects roughly 18.2 million adults and costs the healthcare system more than $21 billion annually.

It is the leading cause of death in individuals age 35 to 50 years.

Approximately 380,000 Americans die of coronary heart disease annually.

Approximately every 25 seconds a coronary event occurs in the US.

75% of the 500,000 deaths from acute coronary thrombosis occur in asymptomatic individuals owing to rupture of an unrecognized coronary artery atheroscleroma.

Approximately every minute someone in US dies of a coronary event.

Although high risk patients have the highest prevalence of cardiovascular events, most occur in the moderate and low risk populations, because the high-risk category represents a small percentage of the population.

The major risk factors include high cholesterol, hypertension, diabetes, and cigarette smoking which explains approximately 87% of coronary heart disease deaths.

About 90% of CAD risk is related to seven health metrics – BMI, physical activity, diet, smoking, total cholesterol, blood pressure, and blood glucose, referred to as life’s simple seven criteria.

Diabetes is the most important risk factor.

Diabetes is a coronary artery disease equivalent with a 2-4 fold increase for its development and the prevalence of acute coronary syndrome is as high as 20% at seven years a follow up.

The most common cause for death among patients with diabetes.

Approximately 1 in 30 patients with stable coronary artery disease experience cardiovascular death or myocardial infarction annually.

In 2009 CHD accounted for 64% of all cardiac deaths.

Prevalence of coronary artery disease in the US between 2007 and 2011 among those 65 years or older was 19.1%

Coronarupy artery disease primarily diagnosed by ((coronary angiography)).

To detect coronary artery disease, a CT scan is more satisfactory than an MRI scan. 

The sensitivity and specificity between CT and MRI were (97.2 percent and 87.4 percent) and (87.1 percent and 70.3 percent), respectively.

Therefore, CT (mainly multislice CT) is more accepted, more widely available, more favored by patients, and more economic. 

Moreover, CT requires shorter breath-hold time than MRI.

In a 1953 study Enos and colleagues reported a 77% prevalence of coronary atherosclerosis among US soldiers killed in the Korean War.

The prevalence of and risk factors for autopsy determined atherosclerosis among US servicemembers 2001-2011, with a mean age of 25.9 years found the prevalence of any coronary atherosclerosis to be 8.5%, severe coronary atherosclerosis was present in 2.3% and moderate in 4.7% and minimal and 1.5%(Webber BR et al).

In the above study older age, lower education, higher BMI, and prior diagnosis of dyslipidemia, hypertension, and obesity were associated with a higher prevalence of atherosclerosis.

The above studies suggest that the prevalence of atherosclerosis is declining among members of the US armed forces, and this fits with the indication that the prevalence of ischemic heart disease has also declined in the general population over a similar period of time.

When comparing the prevalence of coronary atherosclerosis among young American servicemen who died during the Korean, Vietnam, and Iraq and Afghanistan wars there is evidence of decreasing prevalence in the US population.

Women have a 25% increased risk for CAD conferred by cigarette smoking compared with men.

Individuals with a greater number of risk factors have a high coronary heart disease death rate, whereas individuals with none of these risk factors have low coronary artery death rates.

More than a third of adult Americans will develop coronary heart disease during the lifetime.

2005 Behavioral Risk Factor Surveillance System (BRFSS) survey found CAD prevalence of 6.5% among adults 18 years or older, and this number decreased to 6.0% from 2006-2010.

BRFSS survey CAD prevalence men 7.8%, women 4.6%, American Indians/Alaskan natives 11.6%, Asians 3.9%, those with less than college education 9.2% and college educated 4.6%.

Coronary atherosclerosis multifactorial with endothelial injury and dysfunction with adhesion and migration of leukocytes from the circulation to arterial intima with migration of smooth muscle cells from the media to the intima initiating the formation of atherosclerotic plaque.

Mortality rates and incidence have decreased in most Western societies in the past few decades

Decreasing coronary heart disease rates have been associated with less severe and smaller acute myocardial infarctions, more unstable anginal syndromes and lower case fatality rates.

The use of statind and beta blockers associated with a lower risk of presenting with a myocardial infarction compared with stable exertional angina (Yusaf S).

Two types of thrombi form after plaque rupture: a platelet rich clot (white clot) that forms in areas of high stress and only partly occludes the artery, or a fibrin rich clot (red clot) the result of an activated coagulation cascade and decreased flow in the artery.

Red clots are frequently superimposed on white clot and results in complete occlusion of the vessel.

Only white clots are found in unstable angina and non-STEMI, and STEMI associated with red clots (Sherman CT, DeWood MA).

Thrombotic coronary occlusion after rupture of a lipid-rich atheromatous plaque with only a thin layer of intima covering the thin cap fibroatheroma is the most common cause of MI and death from cardiac causes

Age is the biggest risk factor and women’s risk is lower than that of men at any given age.

Leading cause of death among older women.

Prevalence of clinical CAD is almost threefold higher for individuals older than 60 years, compared with younger individuals.

The Cardiovascular Health Study, a longitudinal, population-based study of individuals 65 years of age and older, Among 3584 patients without clinical CAD 61% of men AND 49% OF WOMEN were found to have subclinical cardiovascular(Kuller LH).

In the Cardiovascular Health Study noted above, individuals with subclinical cardiovascular disease had a high rate of cardiovascular events: at 2.4 year follow-up the cardiovascular event rate was 8.2% for men and 3.8% for women, almost threefold higher than individuals without subclinical cardiovascular disease.

More age-dependent in women than in men with one in eight to nine aged 45 to 64 having clinical disease that increases to one in three women older than 65 years.

Premature coronary artery disease defined associated the occurrence of myocardial infarction or the need for a coronary artery procedure before age 55 years for men and 65 years for women.

While there has been a pronounced decline in coronary deaths in men over the last two decades such deaths have not changed, and may be even on the rise for women.

Rates of death fell by more than 40% between 1980 and 2000 which may be attributable half to decrease in major risk factors and approximately half to medical benefits from secondary prevention and treatments for acute coronary syndromes.

Lifestyle changes in myocardial infarction sufferers including smoking cessation, regular physical activity, and dietary improvements may reduce mortality by 20-35%.

Approximately 80,000 lives per year could be saved by secondary preventive strategies.

Mediterranean-style diet is beneficial in primary and secondary prevention of coronary heart disease.

Approximately 7% of the overall drop in deaths from coronary artery disease related to revascularization by coronary artery bypass or angioplasty for stable or unstable disease.

Increases in body mass accounted for approximately 26,000 additional deaths in 2000 and 33,500 additional deaths from increased prevalence of diabetes.

Coronary stenosis of less than 50% is generally perceived as producing no ischemic symptoms and characterizes as non-obstructive disease.

While non-obstructive CAD is thought to be benign there is the view that vulnerability of plaques rather than the extent of luminal narrowing dominates the pathophysiology of future coronary events.

Among patients with chronic coronary disease, most of whom were already receiving proven secondary prevention therapies, 0.5 mg of ((colchicine)) once daily resulting in a 31% lower relative risk of cardiovascular death, myocardial infarction, ischemic stroke, or ischemia driven coronary revascularization.

Surgical therapy may be preferable to medical treatment in patients with stenosis of the left main coronary artery or in patients with three-vessel disease and left ventricular dysfunction, but there is no clear benefit for other patients with coronary artery disease.

Children of parents with premature coronary artery disease have 2.5-7 times higher risk of death from cardiac events.

Approximately 40% of patients do not have elevated LDL cholesterol levels.

African-American women have higher mortality from coronary artery disease than white women.

Among Japanese immigrants to western countries associated with dramatic increases in rates of disease as they adopt western diets.

As countries develop and adopt western diets, the incidence of disease and myocardial infarction increases.

Saturated and trans fatty acids are harmful to coronary arteries while polyunsaturated and menstruated fats are protective.

One alcohol drink per day and 1-2 drinks per day for men are protective against death from coronary artery disease and death from heart attack.

 

Among patients with stable coronary artery disease and moderate or severe ischemia there was no difference in an initial invasive strategy as compared to a initial conservative strategy to reduce the risk of ischemic cardiovascular events or death from any  cause over a median of 3.2 years (Maron DJ).

In patients  with stable ischemic heart disease there is no reduction in mortality or myocardial infarction from angiography followed by revascularization.

ISCHEMIA trial tested revascularization plus optimal medical therapy versus optical medical therapy alone and patients with moderate to severe ischemia established by stress testing: there was no long-term difference in death or myocardial infarction, with a significant difference in diminished angina favoring re-vascularization.

Revascularization relieves angina but has less impact on vulnerable plaques, and there is little effect on later myocardial infarction.

Statin therapy, conversely, substantially modifies atherosclerotic plaque‘s, but has far less effect on the magnitude of stenoses.

 

In a trial population with moderate or severe ischemia patients assigned to invasive strategy had a greater improvement in angina related health status than  those assigned to the conservator strategy: it was a modest mean differences. (Spertus JA).

Most patients have multiple lipid abnormalities, that is a mixed dyslipidemia.

Inverse association between fruit and vegetable intake and risk of coronary heart disease.

Sedentary lifestyle is the most common risk factor for coronary artery disease in women.

Levels of neopterin, and lactoferrin released from activated neutrophil granulocytes, are elevated in patients with CAD, and predict fatal CAD in patients with type 2 diabetes mellitus.

Healthy lifestyle factors associated with a lower risk of incident CAD and all-cause mortality, but the prevalence of low-risk populations in the US is 3-4% (Chiuvre SE et al).

Presently guidelines recommend 30-60 minutes of moderate intensity aerobic activity at least five days a week for patients with stable ischemic heart disease to increase oxygen uptake and modify cardiovascular risk factors, as well as complementary resistance training at least two days a week to increase weight carrying tolerance and skeletal muscle strength.

Resistance training and coronary heart disease may reduce cardiac demands during daily activities.

Nearly all patients with coronary heart disease have at least 1 lipid abnormality.

Majority of individuals who develop coronary disease do not have severely elevated cholesterol.

Coronary plaque burden is a good predictor for future coronary events.

Once women manifest coronary artery disease, they fare worse than men, 42% of women who have heart attacks die within a year compared to 24% of men.

Low concentration of plasma high-density lipoprotein cholesterol (HDL-C) is a major risk factor in coronary heart disease.

Low level of HDL-C concentration most prevalent lipid abnormality in men with known coronary artery disease.

Reduction in incidence in postmenopausal women by smoking reduction, improved diet and increase in use of postmenopausal hormones.

Prevalence increases with age: 1.9%, 5.5%, 9.7% and 12.3% at age 30-39, 40-49, 50-59 and 60-69 years respectively.

Long-term lipid lowering therapy results in slowing of coronary artery disease progression in normocholesterolemic patients and related to changes in lipid levels during treatment.

The use of extended release niacin and fenofibrate have not provided mortality benefit when added to statin therapy, despite widespread use.

People who have coronary events as adults tend to have been small neonates and thin at 2 years of age, thereafter they tend to increase their BMI rapidly and develop insulin resistance in later life.

More than 60% reduction in age-adjusted coronary artery disease mortality rates in the past 4 decades.

Leading cause of death of adult women with mortality rates from heart disease four to six times higher than from breast cancer.

Patients with established coronary artery disease or acute myocardial infarction should have the LDL-C level decreased to less than 100 mg/dL.

Women develop heart disease about 10 years later than men.

Men with low triglyceride levels and high HDL levels have low risk for ischemic heart disease.

Approximately 60% of patients treated with angioplasty or bypass have multivessel disease that could be treated by either procedure.

Risk of disease is 2-6 fold higher in patients with type 2 diabetes than in patients without diabetes.

Diabetic patients without previous myocardial infarction have the same risk of coronary artery disease as patients without diabetes but with a previous myocardial infarction.

Hypertension Optimal Treatment (HOT) trial suggested reduced cardiovascular outcomes for diabetic patients assigned to diastolic treatment goal of less than 80 mm Hg compared to treatment with higher goals (Hannson L).

United Kingdom Prospective Diabetes Study group data indicated tight control of blood pressure reduced macrovascular and microvascular outcomes.

Tight control of systolic blood pressure among patients with diabetes and coronary artery disease is not associated with improved cardiovascular outcomes compared with usual control (Cooper-DeHoff, RM).

In the above study during 16893 patient-years of follow-up the same degree of cardiovascular outcomes was noted among the tight controlled group and the usual treatment control group (Cooper-DeHoff, RM).

Decreasing systolic blood pressure to lower than 130 mm Hg in patients with diabetes and coronary artery disease is not associated with further reduction in morbidity beyond that associated with systolic blood pressure lower than 140 mm Hg, and is associated with an increase in all-cause mortality (Cooper-DeHoff, RM).

Polymer based sirolimus-eluting stents reduce the risk of restenosis.

Angiographic findings after cholesterol reduction demonstrates only minimal decrements in coronary artery stenosis.

Correlation between the severity of a given stenosis and the likelihood of a future acute ischemic event at that site.

A Mediterranean diet with omega-3 and monosaturated fats, fruits, vegetables, legumes and nuts decrease risk of cardiovascular events by 50-70% in patients with coronary artery disease/post myocardial infarction.

Inflammation plays a key role in CAD development with immune cells dominating early atherosclerotic lesions.

Psychological factors have a significant and independent role in the development of coronary artery disease and its complications.

Exercise and stress management reduce emotional distress and improve markers of cardiovascular risk more than medical care alone.

Increased exercise or physical activity and cardiorespiratory fitness mitigates CV disease progression.

Exercise treadmill testing provides information regarding the prognosis in patients with stable coronary heart disease.

Exercise has anti thrombotic , anti atherosclerotic, anti-ischemic, and anti arrhythmic effects.

Most deaths without preceding chest pain are due to coronary disease.

Some patients have silent ischemic disease, such as diabetics, and their outcomes are no different than patients with painful ischemic disease.

When diameter of stenotic vessels exceeds 70% angina and exercise induced ischemia can result.

In stenotic vessels less than 70% occluded may undergo plaque rupture and cause myocardial infarction and or sudden death.

Multivessel coronary artery disease presents difficult problem to determine which lesions are causing ischemia and require stenting.

Among patients who undergo a coronary angiogram and then suffer a subsequent myocardial infarction with  repeat coronary angiogram, in only 34% did the infarction occur as a result of the occlusion of the artery that previously contained the most severe stenosis: that’s why standing does not necessarily reduce cardiovascular disease events.

The Western Norway B Vitamin Intervention Trial (WENBIT), a prospective, randomized, double blind, placebo controlled secondary prevention study of the clinical effects of B vitamins-B12, folic acid and vitamin B6, in patients having undergone coronary angiography for suspected CAD or aortic valve stenosis: results indicated no effect of treatment on total mortality, or cardiovascular events and their use cannot support their use for secondary prevention inpatients with coronary artery disease.

Patients with CAD that have more favorable expectations about recovery and return to normal lifestyle have a better survival, and functional status after hospitilaization (Barefoot JC et al).

Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial showed no difference in outcomes in stable ischemic heart disease-death, myocardial infarction, hospitalization for unstable angina- during a 55 month follow-up between PCI patients and those treated with medical therapy and lifestyle modification (Boden WE. Et al).

Among asymptomatic patients with diabetes, either type one or type two, use of coronary computed tomography angiography (CCTA) to screen for coronary artery disease did not reduce all cause mortality, nonfatal MI, or unstable angina requiring hospitalization at four years:it’s okay it was nothing release findings do not suggest CCTA screening in this population (Muhlestein JB et al).

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