A lumen narrowing of less than 25% is not diagnostic of coronary atherosclerotic heart disease, i.e., coronary artery disease. Coronary artery disease is a common disease in cardiology, and coronary angiography is the gold standard for diagnosing coronary artery disease. Generally speaking, coronary angiography shows that coronary artery lumen stenosis is greater than or equal to 50% before the diagnosis of coronary heart disease. Coronary atherosclerosis is diagnosed when the coronary lumen stenosis is less than 50%. This is because a narrowing of the diameter of the coronary artery greater than or equal to 50% only begins to lead to myocardial ischemia, damage, and furthermore can affect the function of the heart. Although a lumen narrowing of less than 25% does not fulfill the diagnosis of coronary artery disease, it is necessary to prevent the development of coronary artery disease. Patients should consult a hospital in a timely manner and follow the doctor’s instructions for treatment of atherosclerosis to prevent the development of coronary heart disease.