How much is the blood vessel blocked to be a coronary heart disease?The answer is not easy!
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Author 丨 Earth World
Source 丨 Cardiovascular Channel in the medical community
Coronary heart disease is a common disease in the Department of Cardiology, and coronary angiography is a gold standard for diagnosis of coronary heart disease. Generally speaking, coronary angiography shows that coronary stenosis ≥50%can be diagnosed as coronary heart disease, and coronary stenosis <50%can only be called coronary atherosclerosis.
This definition will be emphasized every time we enter the Department of Cardiology for training, but few people will explain its origin. This seems to be a self -evident “axiom.” But just as “there is no love in the world for no reason”, this “50%principle” is not a number without a story.
Previous life: from experimental data to clinical use
The discovery of the “50%Principles” should be attributed to two scholars, Gould and Lipscomb. In the middle of the 20th century, they gradually narrowed the dog’s rotation support until it was completely closed. The coronary diameter was stenosis ≥85%under the static state, and the blood flow would be significantly reduced. When the flow increases by 4-5 times before ligating, the blood flow of the coronary pulse is ≥45%(≈50%), the blood flow has dropped significantly.
This experimental data was quickly transformed into a clinical concept: coronary vein stenosis ≥50%means stenosis of blood flow dynamics, which is equivalent to ischemic stenosis.
Later, everyone followed this standard in clinical research and practice, and gradually reached a consensus: coronary stenosis ≥50%is meaningful, and can be diagnosed as coronary heart disease.
In this life: Actually, coronary stenosis <50%is not innocent
Today, the new concept of atherosclerotic sclerosis cardiovascular disease (ASCVD) adopted by major guidelines also applies this consensus to make the “50%principle” a watershed by diagnosis and treatment.
For example, two patients with different typical angina pectoris, one of the patients with coronary stenosis ≥50%, and another patient’s coronary stenosis is <50%. According to the current guidelines, the former will be regarded as coronary heart disease disease For positive treatment, the latter will be considered a low -risk group, and will soon be mobilized or only preventive measures.
However, in recent years, with the promotion of diagnostic technology and a large number of clinical research, people discovered that coronary stenosis ≥50%does not all mean myocardial ischemia. On the contrary, coronary stenosis <50%is not all low -risk.
For example, Joanned et al. Patients of suspicious coronary heart disease conducted coronary angiography and SPECT load test inspection, and found that 11 of patients with a SPECT load test negative patients were prompting at least one coronary stenosis ≥50%. At the same time, 19 cases were 19 cases. Three of the patients with a positive patient with SPECT load test showed coronary stenosis of the coronary vein <50%. Obviously, the coronary angiography results are obviously inconsistent with the SPECT load test.
For coronary stenosis, and the SPECT load test is positive, we can use coronary microvascular lesions to explain, but the degree of coronary stenosis is heavier and the SPECT load test is negative. There must be myocardial ischemia, which means that the 50%principle is not always established.
Followed by the PROSPECT test published in the 2011 New England Medical Journal (Nejm “, the coronary intervention therapy for 697 ACS patients was followed by 3 years to observe the incidence of cardiovascular events.
The results showed that in the vascular lesions that caused cardiovascular events, non -“criminal diseases” accounted for 11.6%, and most of these initial coronary angiography in non -“criminal diseases” caused by cardiovascular events were displayed as mild narrowing of the lumen. In other words, coronary stenosis <50%does not want what we want, and they are all low -risk lesions. They may still have serious acute coronary syndrome.
TIPS:
The “50%principle” gives us a very clear and clear diagnostic standard, which is conducive to our clinical decision -making and research selection.
However, what we should know is that this “50%principle” only comes from basic experiments, and has its own limitations and deficiencies. We should fully combine clinical situations when applying. If necessary , Internal ultrasound and optical coherent scanning, etc.) Evaluate the physiological significance of coronary stenosis and the stability of plaques.
references:
[1]Gould KL， Lipscomb K， Hamilton GW： Physiologic basis for assessing critical coronary stenosis. Instantaneous flow response and regional distribution during coronary hyperemia as measures of coronary flow reserve. The American journal of cardiology 1974， 33(1)：87- 94.
<!-2664: Cardiovascular terminal pageTomography and Myocardial Performing Imaging. Journal of the American College of Cardiology 2006, 48 (12): 2508-2514.
3.Stone GW, Maehara A, Lansky AJ et al: A Prospective Nature Natural-History of Coronary Atherosclerosis. The New ENGLAND JOURNAL of Medicine 2011, 364 (3): 226-235.
