In-depth analysis of the pathological link between hypertension and coronary heart disease: from arterial intimal damage to the triggers of catecholamine release.

Chapter Two: Sub-health is the Root Cause of Hypertension, Coronary Heart Disease, and Myocardial Infarction. In my country, 50% to 70% of coronary heart disease patients also have hypertension, and the prevalence of coronary heart disease among hypertensive patients is more than four times higher than that among those with normal blood pressure. When blood pressure rises, the pressure within the arteries increases, and the long-term impact of high-pressure blood flow on the arterial walls leads to mechanical damage to the arterial intima. The higher the blood pressure, the more severe this damage. Because the coronary arteries are the first branch of the ascending aorta, they bear a greater impact from the high-pressure blood flow and are therefore more susceptible to damage. Simultaneously, elevated blood pressure also affects the metabolism of connective tissue in the arteries, making it easier for blood lipids to deposit on the arterial walls, leading to atherosclerosis. Furthermore, when blood pressure rises, the activity of higher nerve centers is impaired, and neuroendocrine disorders occur, resulting in excessive release of catecholamines. Increased catecholamines can directly damage the arterial walls, causing coronary artery spasm and promoting the formation of coronary atherosclerosis. Therefore, effectively treating hypertension can reduce or delay the onset of coronary heart disease.

Section 1 Hypertension and Coronary Heart Disease I. Hypertension as an Independent Risk Factor for Coronary Heart Disease Hypertension is an independent risk factor for coronary heart disease; the higher the blood pressure, the greater the risk of developing coronary heart disease. Individuals with systolic blood pressure ≥160 mmHg (21.29 kPa) and/or diastolic blood pressure ≥95 mmHg (12.64 kPa) have a 2-3 times higher incidence of coronary heart disease than those with normal blood pressure. Previously, only the relationship between diastolic blood pressure and coronary heart disease was emphasized. Current research shows that the effect of elevated systolic blood pressure on coronary heart disease is similar to, or even more important than, diastolic blood pressure. Recent studies also show that pulse pressure (systolic blood pressure minus diastolic blood pressure) is the best single indicator for predicting mortality in the elderly. Low diastolic blood pressure and high systolic blood pressure are both independent risk factors for increased cardiovascular disease mortality and all-cause mortality. Pulse pressure is slightly stronger than systolic blood pressure in predicting cardiovascular disease mortality and all-cause mortality, which helps explain the paradoxical phenomenon of high mortality rates associated with low diastolic blood pressure. The incidence and mortality of coronary heart disease increase with increasing blood pressure. The impact of blood pressure levels on the incidence of coronary heart disease can be quantified and can also predict the incidence rate in a population. Therefore, controlling hypertension is crucial for both the prevention and treatment of coronary heart disease.

II. Coronary Heart Disease and Hypertension: "Sister Diseases" Domestic and international data show that approximately 50% to 70% of patients with coronary heart disease also suffer from hypertension. Furthermore, the incidence of coronary heart disease among hypertensive patients is 2 to 4 times higher than among those without hypertension, and the longer the duration of hypertension, the higher the incidence of coronary heart disease. Clearly, there is a close relationship between coronary heart disease and hypertension, which explains why some call them "sister diseases." Hypertension has many causes, but ultimately, it always leads to arteriosclerosis-the hardening of the arterial walls due to increased blood pressure. This hardening and loss of elasticity in the arteries further exacerbates hypertension. The coronary arteries are no exception; they also harden during the pathogenesis of hypertension, making hypertension a significant factor in inducing coronary heart disease. Additionally, with high blood pressure, the heart bears a heavier burden, and the myocardium requires more blood and oxygen, necessitating a greater blood supply to the coronary arteries. However, in the case of coronary heart disease, not only is there no increase in blood supply, but the blood supply to the myocardium is actually reduced. Therefore, in patients with hypertension, the symptoms of coronary heart disease are often more severe. On the other hand, after developing coronary heart disease, the heart is often in a state of partial fullness, which means it is often ischemic, hypoxic, and the heart muscle is weak. The amount of blood pumped out with each heartbeat is also reduced. In addition, when blood pressure is high, the peripheral vascular resistance is very high. In order to maintain the needs of blood circulation throughout the body, the heart must work harder to beat, which means the burden on the heart will become heavier and heavier, and thus the high blood pressure will become more and more severe.

III. Coexistence of Hypertension and Coronary Heart Disease Hypertension is a major risk factor for coronary heart disease. A large amount of epidemiological, clinical, pathological anatomy and experimental data have shown that there is a close dose-response relationship between elevated blood pressure and susceptibility to coronary heart disease. Whether in middle-aged or elderly people, mild, moderate and severe hypertension will correspondingly increase the chance of developing coronary heart disease. Both diastolic and systolic blood pressure increase the incidence of coronary heart disease. It has been proven that the higher the blood pressure, the greater the chance of developing coronary heart disease. The main reasons are as follows: (1) Hypertensive patients have increased coronary artery resistance and reduced coronary blood flow reserve, especially patients with hypertensive myocardial hypertrophy, whose coronary blood flow is reduced more significantly. Coronary artery reserve refers to the increase in blood flow in the human coronary arteries during maximum activity. Normally, it is 60-80 ml/100g myocardium per minute, while coronary blood flow mainly depends on the work of the heart, which in turn depends on the activity of the human body. (1) Hypertensive patients have impaired neuroendocrine function or myocardial arteriolar lesions, which prevents the coronary arteries from reaching maximum dilation with increased cardiac activity. This is called reduced coronary artery reserve and can lead to exertional angina. (2) Hypertensive patients have high blood viscosity, hyperactive platelets, and slow blood flow, making them prone to thrombosis. Coronary artery thrombosis can also easily cause coronary artery spasm, aggravate atherosclerosis and ischemia, and even lead to myocardial infarction. (3) Hypertensive coronary artery pressure increases hemodynamic stress, which can cause and aggravate damage to the vascular endothelium, thereby stimulating the atherosclerotic process. The higher the blood pressure, the more severe the atherosclerosis, and the higher the risk of dying from coronary heart disease.