It is generally believed that myocardial infarction is a disease of the middle-aged and elderly. However, in recent years, the age of onset for myocardial infarction is becoming younger and younger. How can we prevent myocardial infarction? First, we need to know what causes a myocardial infarction.
Let’s start with some basic knowledge about myocardial infarction.
A coronary artery is an artery that supplies blood to the heart, and a myocardial infarction is a failure of blood flow to reach a part of the coronary artery, causing necrosis of the heart muscle.
The main cause for the blood flow to decrease or stop is the narrowing and blockage of blood vessels. And the hardening and narrowing of blood vessels is a long-term process, so patients with myocardial infarction are mostly people over 50 years old.
In the picture below, the raised part of the blood vessel wall is hardened and fibrotic due to cholesterol accumulation. Inside the blood vessel is cholesterol and some cellular fragments, and this causes the blood vessel to become narrow and the blood flow to become not so smooth, which is medically known as “arteriosclerotic plaque,” or “plaque” for short.
Why a Young Person Might Suddenly Die of a Heart Attack, While Someone Elderly Would Survive
There are often news reports of seemingly healthy young people, who suddenly die of myocardial infarction. However, some elderly people with a bad heart conditions have angina pectoris repeatedly, but they recover after taking a rest. Why is that?- Stable arteriosclerotic plaques
A stable arteriosclerotic plaque blocks blood vessels, leaving only a narrow pathway for blood flow. Whenever the burden on the heart increases, such as emotional stress, heavy lifting, and stair climbing, as the blood supply is relatively insufficient, the myocardium becomes ischemic, and angina will occur.
However, after taking a rest, the burden on the heart is reduced, and the balance between oxygen demand and blood supply is regained, and the patient will then recover. In such patients, the blood vessels become increasingly narrow over time, but there are signs before they become completely blocked. This type of stable arteriosclerotic plaques are usually seen among the elderly.
- Unstable arteriosclerotic plaques
In arteries blocked by unstable arteriosclerotic plaques, the blood flow pathways are usually still adequate, and the diameter of the vessels is relatively thick.
Therefore, patients usually do not have any symptoms, and their athletic performance is still decent.
However, at a certain point, the plaques will suddenly rupture and the cholesterol inside them will flow out, triggering a sudden and complete blockage of the coronary arteries. At this moment, a seemingly healthy person would abruptly have a myocardial infarction.
Low Bad Cholesterol Level Reverses Atherosclerosis and Prevents Heart Attacks
Unstable atherosclerotic plaques are relatively complex in composition. There is cholesterol inside a plaque, mixed with some immune cell fragments, and surrounded by an accumulation of various immune cells, smooth muscle cells, and fibroblasts.
The process of atherosclerotic plaque formation is also relatively complex.
In the blood vessels, the part closest to the blood circulation is called the endothelium. Endothelial cells are important for maintaining vascular tone, regulating immune responses and inhibiting vascular smooth muscle proliferation.
They also inhibit platelet aggregation and prevent thrombus formation. As we age, the elasticity of our blood vessels deteriorates, and if blood pressure rises, the endothelium may break down.
At this time, some monocytes will be attracted to where the endothelium is damaged, enter into the arterial walls, and change into macrophages.
After the macrophages become filled with cholesterol, they will become foam cells and accumulate in the blood vessel walls. They would slowly accumulate into cholesterol plaques. They would also cause inflammatory reactions, fibrosis, and calcification.
When the body’s immune system is well coordinated, this condition will not worsen.
In addition, the atherosclerosis plaques can be reduced in size, when the “bad cholesterol” level in your body is low enough.
Bad cholesterol is low-density lipoprotein cholesterol (LDL). Eugene Braunwald, known as the “father of modern American cardiology,” once said that bad cholesterol should ideally be no higher than 50 mg/dL.
Conditions that Cause Atherosclerosis and Trigger a Myocardial Infarction
So, under what circumstances can a sclerotic plaque suddenly rupture and cause an acute myocardial infarction?The force of blood flow that is parallel to the inner wall of a blood vessel is called shear force; the blood pressure that we normally measure is the pressure acting vertically on the vessel wall. Both pressure and shear force may trigger plaque rupture. So a sudden exertion of force, violent exercises, hot and cold temperature changes, emotional agitation, and other situations that cause a sudden increase in blood flow rate and pressure may cause plaque rupture.
When the outer layer of a plaque ruptures, the cholesterol, cell fragments and inflammatory cells inside will escape and have an agglutination reaction with the red blood cells and platelets in the flowing blood, and they will solidify the ruptured plaque into a large piece, thus completely blocking the blood vessel and causing myocardial ischemia and hypoxia, and resulting in myocardial cell death.
Furthermore, since many immune cells have been involved in plaque formation, factors such as inflammation and protease degradation of the plaque shell from within are associated with plaque rupture.
Changing Lifestyle and Habits Can Reduce the Risk of Myocardial Infarction
Therefore, the factors that can cause the accumulation of atherosclerotic plaques and make them unstable and/or rupture are all risk factors for myocardial infarction. However, as long as you start making changes to your unhealthy lifestyle and habits, you can prevent myocardial infarction from occurring.- Risk factors that cannot be changed: Age, gender (men are at a higher risk), and family health history
- Risk factors that can be controlled: Blood pressure, blood cholesterol level, body weight, smoking, stress, exercise, diet, and kidney function
However, some elderly patients have difficulty changing their habits. Their motor function may already be very poor, while weight problems also make these patients’ backs and knees degenerate, further inhibiting their ability to exercise. These patients need to take medication to control their blood pressure, blood sugar, and blood cholesterol levels, as well as aspirin. So many end up needing to take a large amount of drugs every day to reduce the risk of myocardial infarction and stroke in the immediate future.
Many people in their 40s and 50s have relatively minor health problems and may not have a strong motivation to change their lifestyle and/or habits.
However, when in their 50s and 60s, some people will start thinking about taking care of their bodies. If you can seize the opportunity at this stage, when your physical and mental strengths are still strong, you will still have a chance to improve your health. Of course, if you can start taking care of your body earlier, it will be less difficult to improve your habits, and you will get more long-term benefits.
Young People can Prevent Myocardial Infarction by Avoiding 7 Risk Factors
Young people are a minority of myocardial infarction patients, but now their proportion is increasing. Atherosclerotic plaques are starting to accumulate earlier–even in children as young as 8 to 9 years old–and their rate of accumulation is also increasing, perhaps due to a diet based on trans-fats and processed foods and an increasingly stressful and high-pressure lifestyle.These risk factors cover about 85 percent of patients in this age group and are similar to those of other age groups.
Two risk factors, depression and low household income, statistically have a greater impact on young myocardial infarction patients than the rest. This suggests that psychological and social stresses have a significant impact on coronary artery health.
Curiously, low household income was not associated with acute myocardial infarction in men, but only in women. In addition, the most significant risk factors are diabetes and smoking for women, and smoking and a family history of early-onset myocardial infarction for men. Early-onset myocardial infarction is a congenital condition, for which we need to take greater care of our health.
Proper fitness methods are also important.
In the 1970s, the long-distance running movement emerged in the United States. At that time, there was a well-known long-distance running promoter, Jim Fixx, who had written a best-selling book to promote the benefits of long-distance running, and he also often appeared on television. However, he suddenly died of myocardial infarction at the age of 52, which caused a lot of controversy at the time.
The subsequent investigation found that Fixx had smoked two packs of cigarettes a day for a period of time and was under great pressure at work. His father passed away suddenly of heart disease at the age of 35, and Fixx himself had a congenital abnormal enlargement of his heart. At the time, it was thought that long-distance running would have helped Fixx’s health, or he might have died of heart disease even earlier. However, we now have many medical studies proving that excessive exercise can damage the cells of the heart–and there are many cases of athletes dying young.
As the saying goes, “going too far is as bad as not going far enough”–we need to strike a balance in order to better protect our health.
