miércoles, 30 de marzo de 2016

Noninvasive Testing for Coronary Artery Disease - Executive Summary | AHRQ Effective Health Care Program

Noninvasive Testing for Coronary Artery Disease - Executive Summary | AHRQ Effective Health Care Program

AHRQ--Agency for Healthcare Research and Quality: Advancing Excellence in Health Care

Executive Summary – Mar. 29, 2016

Noninvasive Testing for Coronary Artery Disease


Table of Contents


Nature and Burden of Coronary Artery Disease

The public health and economic burdens of coronary artery disease (CAD) are substantial. CAD causes one in six deaths in the United States and is the leading cause of death globally.1 Annually, approximately 635,000 Americans experience a new coronary event, 280,000 have a recurrent ischemic event, and an additional 150,000 have a silent first myocardial infarction (MI).2 A large proportion of ambulatory health care visits are for evaluation of patients with suspected CAD, with an estimated 1.5 percent of the population presenting to health care providers with chest pain every year.3 An estimated $108.9 billion are spent annually on CAD treatment.4Optimizing the process for assessing these patients presents an opportunity to improve patient outcomes and target health resources to where they can have the most impact.
The most common underlying cause of CAD is atherosclerosis, a disease process in which plaque builds up on artery walls and can lead to the partial or complete blockage of coronary arteries. As a result, the heart cannot receive adequate blood, oxygen, and vital nutrients. Plaque causes blockage by two mechanisms: (1) progressive narrowing of the artery because plaque compromises the vessel lumen and (2) thrombotic occlusion of the artery, which occurs when the hard surface of a plaque tears or breaks off and exposes the inner fatty prothrombotic and platelet-attracting components to the site, resulting in enlargement of the blockage. The resulting reduction in blood flow can be either acute or chronic and leads to an imbalance in the blood supply to the myocardium, thus increasing the requirements of the myocardium for oxygenated blood either at rest or during exertion.5,6
The most common symptom of obstructive CAD is chest pain (angina), which is the first presenting symptom in at least 50 percent of patients with CAD.7 Other common symptoms include the angina equivalents dyspnea, early fatigue with exertion, indigestion, palpitations, tightness in the throat, and neck or arm pain. However, because these symptoms are also seen in many common noncardiac conditions, such as gastroesophageal reflux, esophageal spasm, and cervical disc disease, they are much less reliable predictors of CAD. Women and people with diabetes are less likely to experience classic angina, making early diagnosis of CAD challenging in these populations. The onset of symptoms and clinical impact of CAD depend on a variety of factors, including plaque distribution and degree of vessel narrowing; however, lesion severity does not necessarily correlate well with symptoms. Further, CAD may remain asymptomatic for many years.

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