artery (the arteries that supply blood to the heart muscle) develops atherosclerosis. with atherosclerosis, the artery's lining becomes hardened, stiffened, and accumulates deposits of calcium, fatty lipids, and abnormal inflammatory cells – to form a plaque. calcium phosphate (hydroxyapatite) deposits in the muscular layer of the blood vessels appear to play a significant role in stiffening the arteries and inducing the early phase of coronary arteriosclerosis. this can be seen in a so-called metastatic mechanism of calciphylaxis as it occurs in chronic kidney disease and hemodialysis. although these people have kidney dysfunction, almost fifty percent of them die due to coronary artery disease. plaques can be thought of as large "pimples" that protrude into the channel of an artery, causing partial obstruction to blood flow. people with coronary artery disease might have just one or two plaques, or might have dozens distributed throughout their coronary arteries. a more severe form is chronic total occlusion (cto) when a coronary artery is completely obstructed for more than 3 months. cardiac syndrome x is chest pain (angina pectoris) and chest discomfort in people who do not show signs of blockages in the larger coronary arteries of their hearts when an angiogram (coronary angiogram) is being performed. the exact cause of cardiac syndrome x is unknown. explanations include microvascular dysfunction or epicardial atherosclerosis. for reasons that are not well understood, women are more likely than men to have it; however, hormones and other risk factors unique to women may play a role. diagnosis coronary angiogram of a man coronary angiogram of a woman for symptomatic people, stress echocardiography can be used to make a diagnosis for obstructive coronary artery disease. the use of echocardiography, stress cardiac imaging, and/or advanced non-invasive imaging is not recommended on individuals who are exhibiting no symptoms and are otherwise at low risk for developing coronary disease. the diagnosis of "cardiac syndrome x" – the rare coronary artery disease that is more common in women, as mentioned, is a diagnosis of exclusion. therefore, usually, the same tests are used as in any person with the suspected of having coronary artery disease: baseline electrocardiography (ecg) exercise ecg – stress test exercise radioisotope test (nuclear stress test, myocardial scintigraphy) echocardiography (including stress echocardiography) coronary angiography intravascular ultrasound magnetic resonance imaging (mri) the diagnosis of coronary disease underlying particular symptoms depends largely on the nature of the symptoms. the first investigation is an electrocardiogram (ecg/ekg), both for "stable" angina and acute coronary syndrome. an x-ray of the chest and blood tests may be performed. stable angina main article: angina pectoris stable angina is the most common form of ischemic heart disease, and is associated with reduced quality of life and increased mortality. it is caused by epicardial coronary stenosis which results in reduced blood flow and oxygen supply to the myocardium. stable angina is characterized as short-term chest pain during physical exertion caused by an imbalance between myocardial oxygen supply and metabolic oxygen demand. various forms of cardiac stress tests may be used to induce both symptoms and detect changes by way of electrocardiography (using an ecg), echocardiography (using ultrasound of the heart) or scintigraphy (using uptake of radionuclide by the heart muscle). if part of the heart seems to receive an insufficient blood supply, coronary angiography may be used to identify stenosis of the coronary arteries and suitability for angioplasty or bypass surgery. in minor to moderate cases, nitroglycerine may be used to alleviate acute symptoms of stable angina or may be used immediately prior to exertion to prevent the onset of angina. sublingual nitroglycerine is most commonly used to provide rapid relief for acute angina attacks and as a complement to anti-anginal treatments in patients with refractory and recurrent angina. when nitroglycerine enters the bloodstream, it forms free radical nitric oxide, or no, which activates guanylate cyclase and in turn stimulates the release of cyclic gmp. this molecular signaling stimulates smooth muscle relaxation, ultimately resulting in vasodilation and consequently improved blood flow to regions of the heart affected by atherosclerotic plaque. stable coronary artery disease (scad) is also often called stable ischemic heart disease (sihd). a 2015 monograph explains that "regardless of the nomenclature, stable angina is the chief manifestation of sihd or scad." there are u.s. and european clinical practice guidelines for sihd/scad. acute coronary syndrome main article: acute coronary syndrome diagnosis of acute coronary syndrome generally takes place in the emergency department, where ecgs may be performed sequentially to identify "evolving changes" (indicating ongoing damage to the heart muscle). diagnosis is clear-cut if ecgs show elevation of the "st segment", which in the context of severe typical chest pain is strongly indicative of an acute myocardial infarction (mi); this is termed a stemi (st-elevation mi) and is treated as an emergency with either urgent coronary angiography and percutaneous coronary intervention (angioplasty with or without stent insertion) or with thrombolysis ("clot buster" medication), whichever is available. in the absence of st-segment elevation, heart damage is detected by cardiac markers (blood tests that identify heart muscle damage). if there is evidence of damage (infarction), the chest pain is attributed to a "non-st elevation mi" (nstemi). if there is no evidence of damage, the term "unstable angina" is used. this process usually necessitates hospital admission and close observation on a coronary care unit for possible complications (such as cardiac arrhythmias – irregularities in the heart rate). depending on the risk assessment, stress testing or angiography may be used to identify and treat coronary artery disease in patients who have had an nstemi or unstable angina. risk assessment there are various risk assessment systems for determining the risk of coronary artery disease, with various emphasis on different variables above. a notable example is framingham score, used in the framingham heart study. it is mainly based on age, gender, diabetes, total cholesterol, hdl cholesterol, tobacco smoking, and systolic blood pressure. when it comes to predicting risk in younger adults (18–39 years old), framingham risk score remains below 10-12% for all deciles of baseline-predicted risk. polygenic score is another way of risk assessment. in one study the relative risk of incident coronary events was 91% higher among participants at high genetic risk than among those at low genetic risk. prevention up to 90% of cardiovascular disease may be preventable if established risk factors are avoided. prevention involves adequate physical exercise, decreasing obesity, treating high blood pressure, eating a healthy diet, decreasing cholesterol levels, and stopping smoking. medications and exercise are roughly equally effective. high levels of physical activity reduce the risk of coronary artery disease by about 25%. life's essential 8 are the key measures for improving and maintaining cardiovascular health, as defined by the american heart association. aha added sleep as a factor influencing heart health in 2022. most guidelines recommend combining these preventive strategies. a 2015 cochrane review found some evidence that counseling and education to bring about behavioral change might help in high-risk groups. however, there was insufficient evidence to show an effect on mortality or actual cardiovascular events. in diabetes mellitus, there is little evidence that very tight blood sugar control improves cardiac risk although improved sugar control appears to decrease other problems such as kidney failure and blindness. the world health organization (who) recommends "low to moderate alcohol intake" to reduce risk of coronary artery disease while high intake increases the risk. diet main article: diet and heart disease a diet high in fruits and vegetables decreases the risk of cardiovascular disease and death. vegetarians have a lower risk of heart disease, possibly due to their greater consumption of fruits and vegetables. evidence also suggests that the mediterranean diet and a high fiber diet lower the risk. the consumption of trans fat (commonly found in hydrogenated products such as margarine) has been shown to cause a precursor to atherosclerosis and increase the risk of coronary artery disease. evidence does not support a beneficial role for omega-3 fatty acid supplementation in preventing cardiovascular disease (including myocardial infarction and sudden cardiac death). there is tentative evidence that intake of menaquinone (vitamin k2), but not phylloquinone (vitamin k1), may reduce the risk of cad mortality. secondary prevention secondary prevention is preventing further sequelae of already established disease. effective lifestyle changes include: weight control smoking cessation avoiding the consumption of trans fats (in partially hydrogenated oils) decreasing psychosocial stress exercise aerobic exercise, like walking, jogging, or swimming, can reduce the risk of mortality from coronary artery disease. aerobic exercise can help decrease blood pressure and the amount of blood cholesterol (ldl) over time. it also increases hdl cholesterol. although exercise is beneficial, it is unclear whether doctors should spend time counseling patients to exercise. the u.s. preventive services task force found "insufficient evidence" to recommend that doctors counsel patients on exercise but "it did not review the evidence for the effectiveness of physical activity to reduce chronic disease, morbidity, and mortality", only the effectiveness of counseling itself. the american heart association, based on a non-systematic review, recommends that doctors counsel patients on exercise. psychological symptoms are common in people with chd, and while many psychological treatments may be offered following cardiac events, there is no evidence that they change mortality, the risk of revascularization procedures, or the rate of non-fatal myocardial infarction. antibiotics for secondary prevention of coronary heart disease antibiotics may help patients with coronary disease to reduce the risk of heart attacks and strokes. however, the latest evidence suggests that antibiotics for secondary prevention of coronary heart disease are harmful with increased mortality and occurrence of stroke. so, the use of antibiotics is not currently supported for preventing secondary coronary heart disease. neuropsychological assessment a thorough systematic review found that indeed there is a link between a chd condition and brain dysfunction in females/women. consequently, since research is showing that cardiovascular diseases, like chd, can play a role as a precursor for dementia, like alzheimer's disease, individuals with chd should have a neuropsychological assessment. treatment there are a number of treatment options for coronary artery disease: lifestyle changes medical treatment – commonly prescribed drugs (e.g., cholesterol lowering medications, beta-blockers, nitroglycerin, calcium channel blockers, etc.); coronary interventions as angioplasty and coronary stent; coronary artery bypass grafting (cabg) medications statins, which reduce cholesterol, reduce the risk of coronary artery disease nitroglycerin calcium channel blockers and/or beta-blockers antiplatelet drugs such as aspirin it is recommended that blood pressure typically be reduced to less than 140/90 mmhg. the diastolic blood pressure however should not be lower than 60 mmhg. beta blockers are recommended first line for this use. aspirin in those with no previous history of heart disease, aspirin decreases the risk of a myocardial infarction but does not change the overall risk of death. it is thus recommended only in adults who are at increased risk for coronary artery disease where increased risk is defined as "men older than 90 years of age, postmenopausal women, and younger persons with risk factors for coronary artery disease (for example, hypertension, diabetes, or smoking) who are at increased risk for heart disease and may wish to consider aspirin therapy". more specifically, high-risk persons are "those with a 5-year risk ≥ 3%". anti-platelet therapy clopidogrel plus aspirin (dual anti-platelet therapy) reduces cardiovascular events more than aspirin alone in those with a stemi. in others at high risk but not having an acute event, the evidence is weak. specifically, its use does not change the risk of death in this group. in those who have had a stent, more than 12 months of clopidogrel plus aspirin does not affect the risk of death. surgery revascularization for acute coronary syndrome has a mortality benefit. percutaneous revascularization for stable ischaemic heart disease does not appear to have benefits over medical therapy alone. in those with disease in more than one artery, coronary artery bypass grafts appear better than percutaneous coronary interventions. newer "anaortic" or no-touch off-pump coronary artery revascularization techniques have shown reduced postoperative stroke rates comparable to percutaneous coronary intervention. hybrid coronary revascularization has also been shown to be a safe and feasible procedure that may offer some advantages over conventional cabg though it is more expensive. epidemiology deaths due to ischaemic heart disease per million persons in 2012 160–288 289–379 380–460 461–576 577–691 692–894 895–1,068 1,069–1,443 1,444–2,368 2,369–7,233 disability-adjusted life year for ischaemic heart disease per 100,000 inhabitants