Some people think that if there is a heart problem, no matter how serious it is, if the stent is installed earlier, there will be no sudden heart disease in the future. I've seen patients chasing doctors for stents. The doctor explained that mild stenosis does not need stent treatment, and the patient just wants to "prevent problems before they happen."
Some people think that heart stent is a conspiracy of doctors to deceive patients for profit, especially for patients who have a sudden heart attack and are admitted to the emergency department. If the doctor urgently urges the patient's family to prepare for the stent operation as soon as possible, there will be suspicion of "ulterior motives". Family members will immediately pick up the phone and consult all the people they think may be credible to decide whether they should follow the doctor's arrangement.
Recently, it was reported that a study in The Lancet, a top medical journal, thought that stents were useless, which triggered another round of discussion about heart stents.
So, what should we think of coronary stent? Is it useful?
A Study of The Lancet
what did you say ?
This study was published on the internet 1 1.2, which is called the ORBITA study and has attracted some attention in the field of international cardiology.
This is a randomized, double-blind, controlled study involving 200 patients with stable angina pectoris in Britain. Coronary angiography shows that a coronary artery has a stenosis of more than 70%. These subjects were randomly divided into two groups: one group received coronary stent implantation; The other group only received similar surgery, but no stent was placed, that is, sham operation group.
The effect of the operation is evaluated by the length of time that the subject can run on the treadmill. If the blood supply to the patient's heart is improved after stent treatment, the occurrence of angina pectoris will be reduced and the running time will be longer. However, the results show that there is no significant difference in running time between the two groups. There was no significant difference in subjective scores of angina pectoris symptoms between the two groups.
Does this mean that cardiac stents can only bring a placebo effect, but they are actually useless?
It is too early to draw such a conclusion, because stable angina pectoris is only one of the cases of stent application.
The full name of coronary heart disease is "coronary atherosclerotic heart disease". The coronary artery is a blood vessel that supplies blood to the heart itself. If the coronary artery narrows, the blood supply to the myocardium will decrease. Due to the continuous contraction and relaxation of myocardium, when the blood supply decreases, there will be insufficient oxygen and energy.
However, in this process, there are two basically different situations that need different treatment methods.
Acute chest pain:
Interventional therapy is irreplaceable.
If the atherosclerotic plaque on the coronary artery wall suddenly ruptures, it will induce acute thrombosis in blood vessels. At this time, the blood flow of coronary artery will be sharply reduced or even completely interrupted, and myocardial cells will begin to appear necrosis after a period of time without fresh blood and oxygen supply (the time for myocardial cells to tolerate ischemia and hypoxia may be only a few minutes). At this time, the patient will have sudden and long-lasting chest pain (often more than 15 minutes). When they go to the hospital, they will find specific changes in ECG, and blood tests will find that the indicators (myocardial enzymes or troponin) that mark myocardial necrosis have increased. At this time, we diagnosed the patient as "acute coronary syndrome", including the familiar myocardial infarction and other high-risk situations.
Atherosclerotic plaques with fibrous caps rupture, forming thrombi around the rupture orifice and blocking blood vessels.
Percutaneous coronary intervention, including stent implantation, plays an irreplaceable role in acute coronary syndrome. As early as nearly 20 years ago, there was clear clinical evidence that compared with drug thrombolytic therapy, emergency coronary intervention in patients with acute myocardial infarction could reduce the mortality by about 50% and the incidence of secondary myocardial infarction by more than 70%. The possibility of heart failure and myocardial ischemia after myocardial infarction is also significantly reduced in patients receiving emergency coronary intervention.
Therefore, at present, the guidelines for diagnosis and treatment of acute coronary syndrome in various countries clearly point out that direct PCI is the first choice, and it is required to be implemented as soon as possible. For patients with acute myocardial infarction, the prime time for PCI treatment is within 0/2 hours of onset/kloc-,and the time from doctor's visit to unblocking the blocked blood vessels should be completed within 90 minutes.
The annual meeting of the American Heart Association (AHA) is the top academic conference in the global cardiovascular field. AHA20 17 Annual Meeting 1 10 June 15 just ended in the United States. On the second morning of the meeting, John, chairman of AHA? Mr. John. J. Warner suffered from chest pain and was taken to a local hospital. He was diagnosed with acute coronary syndrome and then implanted with a heart stent. On the afternoon before the onset of the disease, Mr. Werner also made a keynote speech by the president of the conference. He mentioned in his speech that he first heard about heart disease when he was 6 years old, because his grandfather died suddenly. He hopes that every family can enjoy family happiness, and their children and grandchildren will be around their knees when they are old. Without a heart stent, it would be much more difficult for President Werner to realize his wish.
But the ORBITA study mentioned above is aimed at another manifestation of coronary heart disease: stable angina pectoris.
Stable angina pectoris:
Some cases need stent treatment.
Patients with stable angina pectoris mainly show chest pain during certain intensity activities. If they stop activities and rest in time, chest pain can be relieved in a few minutes.
When the activity increases, the blood flow required by the heart increases, and the coronary artery will actively expand to increase the blood supply. However, the narrow blood vessels with atherosclerotic plaque can not effectively expand and increase blood flow, and the myocardial cells in the corresponding blood supply area are in a state of ischemia and hypoxia, causing chest pain. When the activity stops, the blood supply required by myocardial cells decreases, and the narrow blood vessels can meet the needs of myocardial blood supply, so the chest pain disappears. (There are also some other causes of stable angina pectoris, accounting for a small proportion. )
Of course, stable angina pectoris may also lead to the sudden rupture of atherosclerotic plaque to form thrombus, which may cause acute coronary syndrome, so these two manifestations may be transformed into each other.
A is normal blood vessel, and B is vascular stenosis caused by atherosclerotic plaque.
For patients with stable angina pectoris, doctors will give them combined drugs (these drugs are also needed by patients with acute coronary syndrome), including: antiplatelet drugs such as aspirin to prevent acute thrombosis; Statins are used to stabilize atherosclerotic plaques and delay the progress of atherosclerotic plaques. Drugs such as beta blockers and calcium antagonists can reduce angina pectoris by controlling blood pressure and heart rate to reduce oxygen consumption of myocardial cells or increase coronary blood supply.
Because the symptoms of angina pectoris are caused by stenosis of blood vessels, it seems theoretically that using stents to open narrow blood vessels and increase blood flow can improve the blood supply to the heart and reduce angina pectoris. Is that really the case?
Coronary stent implantation process. Under the guidance of guide wire, the balloon with stent is placed in the narrow blood vessel segment. After inflation, the balloon expands, opening the narrow blood vessel and releasing the stent. Then, the balloon deflates and retracts, leaving a stent as a support at the opened blood vessel.
In many previous clinical studies, researchers compared the efficacy and safety of stent+drug therapy and drug therapy alone. For example, a study in 2008 included 2,287 patients with stable angina pectoris. Six months and two years after operation, the patients treated with stents (bare metal stents) were significantly better than those treated with drugs only in angina pectoris attack frequency, activity limitation, treatment satisfaction and quality of life. However, the study also found that this advantage gradually narrowed after three years of operation, and there was no significant difference.
A study of 20 12 compared the effects of drug-eluting stent+drug therapy and drug therapy alone. The study found that although stent+drug therapy did not significantly reduce the possibility of death due to heart disease compared with drug therapy alone, it reduced the possibility of patients with acute coronary syndrome and the possibility of emergency PCI of acute myocardial infarction.
In the continuous clinical research, scientists have also developed a variety of technical means, such as using intravascular ultrasound to judge the stenosis degree of blood vessels more accurately, and measuring the blood flow velocity in blood vessels to judge whether there is ischemia, thus guiding clinicians to decide whether stents are needed. Use more methods to help doctors choose the most suitable site for stent treatment from a large number of patients with stable angina pectoris, so as to improve the effect of cardiac stent surgery.
Therefore, in the current guidelines for the diagnosis and treatment of coronary heart disease in various countries, for patients with stable angina pectoris, in some cases with severe coronary artery disease, stent therapy is still recommended as the first choice. Although stent therapy may not reduce the mortality of patients, it can reduce the occurrence of acute myocardial infarction, improve the symptoms of angina pectoris and improve the quality of life of patients.
Stent placement is not without risks. On the one hand, there are certain risks during the operation, such as bleeding and operation-related vascular injury. On the other hand, there is a certain possibility (although very low) that thrombus or intimal hyperplasia will form in the stent after stent implantation, which will lead to stent stenosis and blockage, so patients need oral antiplatelet drugs to inhibit thrombosis. This is why doctors will not install stents for all patients with vascular stenosis.
Do you want to put a bracket or not?
Finally, let's go back to the study of The Lancet. In this study, a control scheme of stent implantation and sham operation, which has never been used before, was adopted to further eliminate the placebo effect of surgery on the subjects. In the evaluation of angina symptoms and quality of life, it can be said that the results tend to be more objective.
But on the one hand, the number of people selected in the study is small, only 200, and the extent to which it can represent all patients with stable angina remains to be discussed. On the other hand, the subject's own coronary artery disease is relatively "mild"; According to the article, according to the current clinical guidelines, about 30% of these subjects do not need stent treatment. This deviation in the choice of subjects also affects the authenticity of the results to a greater or lesser extent.
But in any case, this study has sounded the alarm for medical experts to rethink whether cardiac stents can achieve the expected results, or how to choose the most suitable patients for stent treatment.
For the general public and patients with coronary heart disease, it needs to be clear that stents can not solve all problems. For patients with stable angina pectoris, the rational choice is to fully evaluate and weigh the benefits and risks brought by stent surgery according to the severity of symptoms and the degree of vascular stenosis, and discuss with doctors whether to accept stent treatment. When serious cardiovascular events such as acute coronary syndrome occur, emergency PCI is the most recommended first choice, so don't delay the best opportunity for treatment because of hesitation.