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Summary
This chapter discusses the pathophysiology, diagnosis, and treatment of nonobstructive atherosclerotic and nonatherosclerotic coronary heart diseases, including coronary microvascular dysfunction, epicardial coronary spasm, vasculitides, transplant vasculopathy, congenital abnormalities, and dissection and trauma (see accompanying Hurst's Central Illustration). Macrovascular diseases typically arise from pathological alterations of the intimal, medial, and/or adventitial layers of the coronary arteries, whereas microvascular disease mainly results from endothelial cell and/or vascular smooth muscle cell dysfunction. Nonobstructive coronary artery disease occurs more frequently in women than in men. Lack of available evidence means that guideline recommendations for treatments for coronary microvascular dysfunction and nonobstructive coronary artery disease are sparse; among the few recommended treatments, most have been adopted from the treatment of patients with angina pectoris related to obstructive coronary atherosclerosis. Treatment of patients with coronary spasm includes pharmacotherapy as well as elimination of risk factors. Immunomodulatory drugs are used to treat patients with vasculitides. Transplant vasculopathy has few therapeutic options, with repeat transplantation being the only definitive treatment; medical management may have some effect and percutaneous coronary intervention is an option for focal stenoses. Surgery or percutaneous interventions tend to be chosen as the treatment modality for most congenital abnormalities. Percutaneous and surgical treatments are options for dissection, but many are managed conservatively without need for revascularization.
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Although obstructive coronary atherosclerosis and myocardial infarction tend to be predominant topics when discussing coronary heart disease, many other clinically relevant processes affect the coronary arteries. In this chapter, we will discuss a wide array of nonobstructive atherosclerotic and nonatherosclerotic coronary heart diseases. Our discussion will begin with pathology of the coronary artery intima and media, then move to diseases that affect the entire coronary tree, and conclude with physical abnormalities of the coronary arteries and mechanical disruption of coronary blood flow. Most of these diseases, however, can overlap and adversely interact. For example, coronary microvascular dysfunction (CMD) contributes to angina in patients with obstructive atherosclerosis, coronary spasm can occur at both micro and macro levels, and inflammatory disease can have an impact on the entire coronary tree.
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NORMAL CORONARY ANATOMY AND FUNCTION
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The normal arrangement of the coronary arteries is for the left main artery and right coronary artery to arise from the ascending aorta, 1 to 2 cm above the base of their respective coronary sinuses. The left main artery divides into anterior descending and circumflex branches, which travel in the interventricular and atrioventricular grooves, respectively. The right coronary artery also travels in the atrioventricular groove on the right side of the heart, typically terminating in the posterior descending artery in the inferior interventricular groove. Each vessel gives rise to branch vessels to create a comprehensive network of epicardial conduits. Vessels branch and decrease in ...