Cardiovascular disease is the single most common cause of death in the developed world and accounts for almost 1 million fatalities in the United States a year. Of these cardiovascular deaths, nearly half results directly from coronary artery disease.
Coronary Artery Disease (CAD) is most commonly due to obstruction of the coronary arteries by atheromatous plaque or by thrombosis. There are several risk factors that predispose to this condition. These include the following: male gender, age, familial predisposition and diabetes mellitus, which are non-modifiable. There are risk factors that can be modified and this includes the presence of hypertension, dyslipidemia, obesity, stress and cigarette smoking. No uniform syndrome of signs and symptoms are initially seen in patients with coronary artery disease. Chest discomfort or angina pectoris is usually the predominant symptom in chronic (stable) angina, unstable angina, Prinzmetal (variant) angina, microvascular angina and acute myocardial infarction. Angina pectoris is characteristically described as a retrosternal chest discomfort that has a close relation to physical or emotional stress and is rapidly relieved with rest or nitrates. Angina pectoris results from myocardial ischemia, which is caused by an imbalance between myocardial oxygen requirements and myocardial oxygen supply. The former maybe be elevated by increases in heart rate, left ventricular wall stress and contractility, and the latter is determined by coronary blood flow and coronary arterial oxygen content. Aside from chest discomfort, there are other cardinal manifestations of CAD. These are dyspnea, orthopnea, paroxysmal nocturnal dyspnea (PND) and syncope.
Several diagnostic modalities are now available for the detection of CAD. One of the best screening tests is by the use of resting electrocardiogram (ECG). Although the sensitivity of ECG is low for the diagnosis of ischemic heart disease-normal in almost half of patients presenting with ischemic heart disease, it does provide a prognostic information. Other non-invasive diagnostic tests that can be used to detect CAD are the exercise electrocardiogram, 2-dimensional echocardiography (2-D Echo) and myocardial perfusion imaging. Coronary angiography is also used to aid in the diagnosis and management of known or suspected coronary heart disease, and is considered when either medical therapy has failed to provide effective symptomatic control or clinical non-invasive test suggest that the patient may be at high risk, or otherwise, may benefit prognostically from intervention.
The treatment of patients with CAD should be directed towards the alleviation of symptoms and an improvement in prognosis. These involve several approaches and therapeutic modalities, including lifestyle modification, management of risk factors, pharmacologic therapy and coronary revascularization. All forms of intervention present certain hazards and should be instituted only if the perceived benefits, in terms of improved symptoms and prognosis, are likely to outweigh the associated risks.
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