Hypertension, the Silent Killer: Unveiling the Physiological and Pathological Mechanisms of Vascular Intima Damage and Cardiac Hypertrophy

Hypertension is a systemic disease characterized by elevated arterial blood pressure (systolic blood pressure 140 mmHg and diastolic blood pressure 90 mmHg), which can be accompanied by heart, vascular, brain, and kidney damage. In simple terms, when a person has hypertension, it reflects more than just a problem with blood pressure; it often indicates that the body's pump (heart), blood vessels, command center (brain), and filter (kidneys) have already experienced or are about to experience a "malfunction" (ischemia, hypoxia, necrosis). These "departments" are all major organs of the body, and serious "malfunctions" can lead to death.

When the body's blood glucose level exceeds the upper limit of normal (fasting blood glucose 7 mmol/L), it is called hyperglycemia. Elevated blood glucose is a major characteristic of diabetes. If you have hyperglycemia, the first thing to consider is whether you have diabetes; it should never be taken lightly!

What is hyperlipidemia? When the concentration of plasma lipids (cholesterol, triglycerides, phospholipids, free fatty acids, and lipoproteins) exceeds the upper limit of normal, it is called hyperlipidemia. Normal blood lipid levels are: cholesterol 3.4–5.95 mmol/L; triglycerides 0.8–1.8 mmol/L; low-density lipoprotein (LDL) <4.1 mmol/L; high-density lipoprotein (HDL) 0.88–1.63 mmol/L. Doctors often don't rely on a single measurement to determine if a person's blood lipids are high or low, because blood lipid levels fluctuate daily. At least two or more consecutive blood lipid tests over two to three weeks are needed to confirm the presence of high blood lipids. Dr. Kang: Now that you know what the "three highs" are, you also need to know the troubles that come with them!

First High: High blood pressure causes more than just dizziness, headaches, and memory loss. The biggest problem it causes is damage to vital organs. Blood vessels are the channels through which blood flows, and their condition directly affects blood flow—the delivery of nutrients. Normal arterial walls are composed of the intima, media, and connective tissue. These are both smooth and have complex physiological functions. When a person develops hypertension, the inner lining of their blood vessels is damaged.

① Diffuse intimal thickening;
② Focal intimal edema;
③ Fatty streaks (points);
④ Fibrous plaques. In fact, in most cases, hypertension is a symptom, while atherosclerosis is the underlying cause. Arteriosclerosis precedes hypertension; this is a compensatory function of the circulatory system. Decreased vascular elasticity and impaired blood flow force the heart to exert greater effort to faithfully deliver nutrients to the whole body. Simultaneously, higher blood pressure further exacerbates arteriosclerosis, becoming one of the important causes of the aforementioned vascular lesions (hypertension has other causes as well). These vascular lesions are like a torn lining in our clothes. A torn lining makes the clothes prone to snagging and deformation. Deformed clothes affect appearance. Once arteries become deformed, it affects more than just their appearance; primarily, it impairs their function—the delivery of nutrients and oxygen—leading to illness! High blood pressure damages the heart. Everyone knows the importance of the heart, as it's the body's "pump." Heart problems are no joke; they can range from hospitalization to death!

The heart is a hollow organ with valves, composed of cardiac muscle tissue, and is the driving force behind blood circulation. During life, the heart constantly contracts and relaxes, allowing blood to be pumped into the blood vessels. When a person suffers from high blood pressure, the long-term elevation of blood pressure alters the structure and function of the heart, leading to ventricular hypertrophy in the early stages and heart failure in the later stages. Ventricular hypertrophy caused by high blood pressure often manifests in two types: "concentric" and "eccentric."

1. "Concentric" hypertrophy: The ventricular walls thicken, and the heart chambers are not enlarged. This hypertrophy increases the contractility of the myocardium to improve the heart's pumping function. However, this increase in myocardial contractility has its limits. For example, if you can only lift 50 kg, but are asked to lift 80 kg, you might be able to for a while, but you'll eventually give up and put the load down. If you insist on carrying it, you'll strain your arm.

2. "Eccentric" hypertrophic heart: The heart chambers enlarge, but the ratio of the ventricular wall to the ventricular cavity does not increase. This is similar to plastic bags; the large and small bags are not the same thickness. This allows the large bag to bear more weight due to its increased volume. An "eccentric" hypertrophic heart only increases volume without increasing the thickness of the ventricular walls. Imagine, wouldn't the heart malfunction?