Keywords: etiology and pathology of coronary heart disease
Coronary atherosclerotic heart disease
Coronary atherosclerotic heart disease, referred to as coronary heart disease or coronary artery disease, sometimes known as coronary artery disease, or ischemic heart disease that lead to myocardial ischemia due to coronary atherosclerosis, hypoxia cause of heart disease. For atherosclerosis leads to the most common type of organ involvement.
Coronary heart disease or coronary heart disease the acronym, has been widely used, but it is not expressed atherosclerosis this cause, and have a broader meaning. Because based on the cause of coronary artery disease, myocardial ischemia and hypoxia addition to coronary atherosclerosis, inflammation (rheumatic, syphilitic and vascular obliterans, etc.) spasm, embolism, connective tissue disease, trauma and a variety of congenital malformations, coronary heart disease, the term actually includes all of these cases are caused by the heart attack. Since the vast majority (95% – 99%) caused by coronary atherosclerosis, instead of the term coronary heart disease or coronary heart disease coronary atherosclerotic heart disease, although not quite exact, clinically feasible. As for coronary artery disease or coronary atherosclerosis as a synonym for coronary atherosclerotic heart disease, is not exact. Because coronary sick, although the occurrence of atherosclerosis, but may not have been caused by myocardial ischemia and hypoxia, or coronary artery disease has been demonstrated in the clinical, but no evidence of myocardial ischemia and hypoxia, can only be considered patients suffering from coronary artery disease or coronary atherosclerosis, and can not be considered to have been suffering from coronary atherosclerotic heart disease. In addition, the term ischemic heart disease, its meaning should be broader.
[The etiology and pathogenesis]
This disease is atherosclerosis due to coronary atherosclerosis, the most important risk factors of age, male, hyperlipidemia, hypertension, smoking, and diabetes. Coronary artery was apt to occur atherosclerosis might be: ① the arterial intima and the blood supply of the portion of the film is directly supplied by the lumens, the blood oxygen and nutrients directly penetrate into the intima and media, and thus lipid also easy penetration. ② the angle of intersection of the artery and the aorta is almost perpendicular to the proximal end and the proximal end of the main branches of the bloodstream by impact, and thus vulnerable to injury.
Also found that in recent years, is closely related to platelet function and the pathogenesis of this disease. Most platelet function of patients with this disease hyperthyroidism, induced poly variety of factors sensitive survival time increased circulating blood platelet aggregation rate, release reaction occurs, release of β thromboglobulin, platelet factor IV, platelet-derived growth factor, diphosphate adenosine, 5 – serotonin, catecholamines, thromboplastin, histamine, thromboxane A2. These substances so that more platelet aggregation and the formation of blood clots; increase the permeability of the coronary arteries; coronary vasospasm, damage the vessel wall; promote vascular smooth muscle cell proliferation leading to coronary atherosclerosis.
Pathological anatomy and pathophysiology]
Coronary or so, two openings, respectively, in the left and right aortic sinus. 1 ~ 3cm long-General of the left coronary artery, and then divided into the left anterior descending artery and the circumflex artery. Anterior descending artery blood supply to the lower part of the left ventricular anterior wall in 2/3 of the ventricular septal and apical stenosis outside the papillary muscle and left atrium; circumflex artery blood supply to the left atrium and left ventricle forearm upper lateral wall of the left ventricle and the heart of the phrenic left part or all of the surface and mitral papillary muscle. Right coronary artery to the right ventricle, ventricular septum after 1/3 and the right side of the diaphragmatic surface of the heart, or all. Between the three coronary arteries, there are many small branches mutual agreement, together with the trunk of the left coronary artery, collectively known as the four coronary arteries.
Atherosclerosis involving four in one, two or three, and also four coronary involvement. Which is most prevalent in the left anterior descending artery involvement, the lesion is also the heaviest, and then turn to the right coronary artery, the left circumflex artery and the left main coronary artery. Too, more distal lesions in blood vessels proximal main vessel disease more weight than the edge of the branch. Atheroma distributed in vascular branch openings, and often biased towards one side of the blood vessels, crescent-shaped, sufficient to gradually understand the changes caused by stenosis or occlusion of the disease have been elaborated in “atherosclerosis" .
Coronary atherosclerosis development to a certain extent, will affect the blood supply to the myocardium. Needs blood and myocardial coronary blood supply is a contradiction between the two aspects of the unity of opposites. Under normal circumstances, through the regulation of neural and humoral both maintain a dynamic balance when mild stenosis of the vascular lumen (<50%), the myocardial blood supply was not affected, patients are asymptomatic, various cardiac stress test. did not show the performance of myocardial ischemia, and therefore although coronary atherosclerosis, also can not believe that there are coronary heart disease. 50%～75%)，其对心肌血供的能力大减，心肌发生缺血，是为冠心病。">When the vessel lumen severe stenosis (> 50% to 75%), the ability to greatly reduced myocardial blood supply to an ischemic myocardium, for coronary heart disease. Coronary blood supply less than the size of the range, depending on the size of the diseased arteries and how much its extent depends on the degree of stenosis and lesion development speed. The slow development of small arterial anastomotic branch blood flow due to compensatory increases gradually thickening, enhanced collateral circulation, improve myocardial blood supply, even if the artery lesions were more severe myocardial injury is not heavy; development of more fast, lumen quickly clogged, myocardial injury occurs, necrosis; myocardial long-term lack of blood supply, causing myocardial atrophy, degeneration, fibrosis, enlargement of the heart.
In addition, the atherosclerotic plaque hemorrhage or rupture atherosclerotic coronary atherosclerotic lesions (also) spasm or diseased artery thrombosis, and can be quickly and severely narrowing or blockage of the arterial lumen, causing myocardial acute ischemia or necrosis.
Due to the different parts, the scope and extent of coronary artery disease, the different clinical characteristics of the disease, generally can be divided into five types.
1, occult or asymptomatic coronary artery disease, asymptomatic ECG changes of myocardial ischemia. Myocardial morphological changes unorganized.
2 retrosternal paroxysmal pain, angina, for the moment of myocardial blood supply caused by the shortage. The myocardial no more tissue morphological changes.
3, severe myocardial infarction symptoms for coronary artery obstruction caused by acute myocardial ischemic necrosis.
4, ischemic cardiomyopathy, long-term myocardial ischemia induced myocardial fibrosis gradually, formerly known as myocardial fibrosis or myocardial sclerosis. Performance of cardiac enlargement, heart failure, and (or) arrhythmia.
Sudden death sudden cardiac poly arrest and death, mostly for the heart of local the electrophysiological disorder or pacing cause severe arrhythmia, conduction disorder occurs.
In recent years, it was suggested that the acute coronary syndrome term, refers to the sudden decrease in coronary acute changes in blood flow, causing unstable angina, acute myocardial infarction, or sudden death.