Hypertension is a major predisposing factor for coronary heart disease, which has been confirmed by numerous studies at home and abroad. The relationship between hypertension and coronary heart disease is complex and multifactorial. In fact, differences in absolute levels of coronary heart disease risk between hypertensive patients often depend to a greater extent on risk factors other than blood pressure levels. Since the Framingham study, several prospective studies have shown that hypertension at any age and gender, whether stable or unstable, systolic or diastolic, mild or severe, is an independent risk factor for the development of coronary heart disease. Epidemiological studies have shown that the risk of coronary heart disease from elevated blood pressure does not decrease with increasing age, and the relative risk of coronary heart disease onset is higher for older adults than for middle-aged adults for the same magnitude of blood pressure increase; although the incidence of coronary heart disease in women is lower than in men, the relative risk factors for coronary heart disease onset in women and men for the same blood pressure level are the same. jNC7 states that over 50 years of age, systolic blood pressure >= 140 mmHg, is a more important risk factor for cardiovascular disease (CVD) than diastolic blood pressure. The risk of CVD increases 1-fold for every 20/10 mmHg increase in blood pressure from 115/75 mmHg. A prospective study of risk factors for coronary heart disease in Shougang men showed that the relative risk of coronary heart disease was 40% higher at a systolic blood pressure of 120-139 mmHg than those <120 mmHg and 1.3 times higher than those 140-149 mmHg, similarly indicating the role of elevated blood pressure in the development of coronary heart disease in the Chinese population. Acute myocardial infarction can be induced by a sharp increase in blood pressure. There are 500,000 new myocardial infarction patients and 1.5-2 million cumulative surviving myocardial infarction patients in China each year.