Recently, the price of coronary stents has dropped from 13,000 yuan to 700 yuan, which has become a topic after dinner
You need to understand these things
Written by Liu Zhirong
On November 5, 2020, my country’s first centralized procurement of cardiac coronary stents was opened in Tianjin. A total of 10 domestic and imported stents won the bids. The average price dropped from 13,000 yuan to 700 yuan. The 95% rate is shocking. The huge profits are evident.
The well-known cardiovascular expert Hu Dayi stated at the 23rd Great Wall International Conference on Cardiology that the heart stent is half unreliable, and the profit is 9 times more than drug trafficking. In the case of stable condition, it is not recommended to install the stent.
Some people are also worried about the quality of stents after the price reduction. Yang Weixian, vice president of Fuwai Hospital, Chinese Academy of Medical Sciences, explained: “Of the top 10 commonly used coronary stents, 7 have been selected. These products are mainstream products commonly used in hospitals. There is no question of alternative products."
1 Why are Chinese people so concerned about stents
In the past few years, coronary stent implantation surgery has become popular in China, and stents have become a topic after dinner.
Although the price of stents has fallen in the past two years, many families still cannot afford it.
The People’s Daily reported on November 20, 2020 that Li Qiang, a 59-year-old patient with myocardial infarction in Henan, had 6 coronary stents implanted in September 2020. The medical expenses were as high as 220,000 yuan. After being reimbursed by medical insurance and critical illness supplementary insurance, Li Qiang Pay 100,000 yuan by yourself.
After Li Qiang was discharged from the hospital, he still had to take 11 kinds of drugs every day, including anti-thrombotic drugs and diabetes drugs after stent implantation.
The high price of stents is caused by many factors, but there are many corruption factors such as doctors' rebates.
On May 22, 2019, Xinhua News Agency published a report titled "Doctoral students report the stent recovery buckle for indiscriminate installation of stents: a rebate of 10,000 yuan for installation". Yang Xiangjun, chief cardiovascular physician at the First Affiliated Hospital of Soochow University, received the stent installation indiscriminately. Rebate, more than 600 cases of interventional cardiac surgery are performed every year.
On August 8, 2019, the Suzhou Municipal People’s Procuratorate made a decision to arrest Yang Xiangjun on suspicion of accepting bribes.
2 The invention of the bracket changed the world
In 1969, Robert A. Elsek, MD, University of Minnesota, USA, performed a stent implantation operation for animals, and in 1972 applied for the world's first stent patent.
But the widely used balloon stent was invented by Argentine vascular imaging doctor Julio Palmas, who applied for a patent for the invention of this stent in 1985.
It should be noted here that the stent can be implanted into various lumens of the human body, such as blood vessels, urinary tract, gastrointestinal tract, airway, biliary tract, pancreas, prostate, etc.
On March 28, 1986, French doctor Jacques Pierre and German doctor Ulrich Siegwart implanted a stent into a patient’s coronary artery in Toulouse, France. This is the world’s first human coronary stent Implant surgery.
Coronary stents continue to improve, from bare metal stents to drug-eluting stents, covered stents, and degradable stents.
Currently, more than 2 million patients worldwide undergo coronary stent implantation operations every year.
The invention of the stent was listed in the "10 Most Important Inventions That Changed the World" by the American "World Intellectual Property" magazine.
There are nearly 1 million coronary stent implantation operations in China each year, with an average of 1.5 stents implanted in each case, and 1.5 million stents are implanted in the coronary arteries of patients each year.
3 Why stent implantation for coronary artery
The heart beats about 100,000 times a day. The right atrium pumps venous blood back into the right ventricle and pumps it into the lungs. The blood is pumped into the left atrium after removing carbon dioxide from the lungs and loaded with oxygen. This oxygen-rich blood flows from the left atrium. It enters the left ventricle and pumps into the aorta to flow throughout the body.
But the oxygen required by the heart wall is provided by the arteries surrounding the surface of the heart. Since these arteries look like a crown, they are called "coronary arteries".
The oxygen supply range of the left coronary artery is wider than that of the right coronary artery, and the left coronary artery is more likely to develop disease.
Lipids accumulate in the lining of blood vessels for various reasons. These millet atherosclerotic lipids narrow the lumen of blood vessels and harden the walls of blood vessels. This phenomenon of blood vessels is called "atherosclerosis."
We often say "coronary heart disease" is the abbreviation of "coronary atherosclerotic heart disease".
When the coronary artery is blocked by more than 75% (cross section), the myocardium consumes more oxygen, resulting in insufficient blood flow and oxygen supply, and angina pectoris will occur.
After the occurrence of angina pectoris, general oral administration of nitroglycerin tablets (which dilate blood vessels) can be relieved within a few minutes; if 3 consecutive administrations of nitroglycerin tablets still do not relieve, you should seek medical attention immediately.
Once the plaque in the hardened area falls off, the body’s immune system thinks it has been attacked and injured by the outside world. Platelets quickly accumulate on the surface of the ruptured plaque to form a thrombus. The thrombus completely blocks the blood vessel at the stenosis of the blood vessel. If the blood flow is blocked for more than 15% Minutes, myocardial cells die due to hypoxia, which is called "myocardial infarction" or "myocardial infarction" for short.
After a myocardial infarction, measures must be taken as soon as possible to make the blood flow again.
At present, there are two most common measures. One is thrombolytic therapy, in which a thrombolytic agent is injected into the vein to dissolve the thrombus and open the blood vessel; the other is interventional therapy, where a stent is implanted in the cavity of the blocked blood vessel, which is what we often say The "stent placement" is used to physically stretch the blood vessels and open up the blood vessels.
It is not that the stent must be implanted if the vascular obstruction exceeds 75%. This is just a primary reference indicator for the implantation of the stent. The more accurate parameter of the implantation of the stent is the coronary flow reserve measurement (FFR), which is to measure the maximum blood volume of the diseased vessel. The ratio of blood flow to the maximum blood flow under normal conditions is used to judge the degree of myocardial ischemia.
Although the blood vessels are narrowed, the flow of blood through the stenosis is faster, and the blood flow can still be close to the blood flow under normal conditions. The myocardium will not be ischemic, so there is no need to implant a stent.
The theoretical normal value of blood flow reserve measurement is 1, and the stent can be selectively implanted between 0.8-0.75, and it is necessary to implant the stent below 0.75.
In countries such as Japan, if the stent is implanted without a coronary blood flow reserve measurement, it is deemed to be blindly implanted and the insurance company refuses to pay for medical expenses.
It needs to be emphasized here that there are many ways to dredge blood vessels, and stent implantation is only one of them.
There is also a drug balloon, which is to apply a layer of drug to the vascular stenosis after opening the balloon, leaving the drug on the diseased blood vessel wall to prevent vascular endothelial proliferation, and then withdraw the balloon.
There is also atherectomy, which is like a tunnel digging shield machine, which cuts the plaque that blocks the blood vessel layer by layer and sucks it out of the body.
4 How is the stent implanted into the coronary artery
Stent implantation is performed on the basis of "puncture".
"Needle" is also called "Seldinger puncture". It was invented by Swedish scientist Sven Ivar Seldinger in 1953.
First, perform a "digital subtraction angiography" (DSA) of the coronary arteries to determine the location of the blockage.
The angiography technique was proposed as early as 1935 and has been clinically used since the 1970s.
During X-ray imaging, the background images of bones and other soft tissues are subtracted to make the imaging of blood vessels containing contrast agents clearer.
During angiography, first perform local anesthesia on the radial artery on the right wrist (or femoral artery at the base of the thigh) and puncture the arterial sheath.
The arterial sheath is the gateway for angiography and stent implantation. All instruments and devices are put in or withdrawn through the arterial sheath.
Next, a guide wire is inserted through the arterial sheath, and under the full monitoring of the X-ray imaging device, the guide wire is carefully twisted into the coronary artery.
Put the catheter on the guide wire, let the catheter follow the guide wire to the coronary artery opening, and then withdraw the guide wire.
Since blood cannot block X-rays, a contrast agent must be injected into the coronary arteries. The contrast agent blocks the X-rays. In this way, the blood vessel lumen is displayed on the monitor.
If a part of the blood vessel suddenly becomes thinner, it proves that the part is narrow.
After completing the angiography, withdraw the catheter from the blood vessel, then insert the guide wire, and then feed the balloon catheter along the guide wire to the vascular blockage. The external pressure is applied to fill the balloon, and then the decompression allows the balloon to collapse. Several operations stretched the narrowed blood vessel open, and then the balloon catheter was withdrawn from the body.
If a stent needs to be implanted, the balloon catheter containing the stent is inserted again, and the stent is attached to the balloon at this time.
When the balloon enters the narrow part of the blood vessel, the balloon is filled with external pressure and the stent is stretched and fixed on the blood vessel wall.
In order to make the implanted stent more stable, the balloon is usually left in an inflated state for 30 to 60 seconds, and then decompressed to collapse the balloon, withdraw the balloon catheter, and the stent is permanently left on the vessel wall.
Generally speaking, a coronary angiography and stent implantation operation takes 30 minutes to 60 minutes; of course, if more stents need to be implanted, the time will be longer.
After the arterial sheath is pulled out, the bleeding is stopped, and the stent implantation operation is complete.
Patients can go home after one day of hospitalization for observation after surgery, and some do not need to be hospitalized.
Contrast agents can harm the kidneys, and some people are also allergic to contrast agents.
Therefore, after an angiography or stent implantation operation, the doctor will allow the patient to drink more water to expel the contrast agent through the kidney as soon as possible; if the patient is allergic, use an anti-allergic drug.
Readers must be clear that implanting a stent is only a physical treatment, not a cure for coronary heart disease. The patient is still a coronary heart disease patient after the stent is implanted. In order to prevent the blood vessel from being blocked again, long-term medication must be taken.
Let’s make an analogy. Your house’s sewer is blocked. Ask a plumber to unblock it. The blocked part is cleared, and the sewage flows smoothly again.
However, if the floor drain and other water inlets are not treated, large solids will still enter the sewer and the sewer will be blocked.
To prevent clogging of the sewer, it is necessary to eliminate the clogging factor and place a filter at the water inlet to prevent larger solids from entering the sewer.
The same is true for implanting a stent. It only physically dredges the coronary arteries, treating the symptoms but not the root cause, and does not eliminate the factors that cause vascular blockage. If the stent is implanted without taking anticoagulant drugs, the blood vessels at the stent are more likely to be blocked.
5 Stent implantation is the last choice when drugs are ineffective
Stent implantation is a very mature operation. The operation is simple, easy and relatively safe, but it also causes the problem of excessive implantation of stents.
Many international studies have shown that about one-third of stent implantation operations are unnecessary.
The British stent implantation research team published a research report in The Lancet in 2017. The report concluded that for patients with stable angina pectoris, implantation of stents may not be effective; some patients could be treated with drugs, but stent implantation is The last choice when the drug is ineffective.
The study selected 230 patients with stable angina who had at least one coronary artery stenosis.
The researchers asked the 230 patients to take angina pectoris medications, such as beta-blockers or long-acting nitroglycerin, for 6 weeks. At the same time, 80 of them were implanted with stents and 115 of them were pretended to be implanted with stents ( Let the patient think that the stent is really implanted).
After 6 weeks, the angina pectoris of these 230 patients was relieved and stabilized. There was no significant difference in clinical manifestations between patients without stent implantation, patients with stent implantation, and patients with stent implantation.
Rita Redberg, a cardiologist at the University of San Francisco in the United States, explained: “The stent acts as a placebo, just like a sugar pill. We know that sugar pills can make many patients feel relieved.”
David Brown, a cardiologist at the University of Washington School of Medicine in the United States, has studied the side effects of stents for more than ten years. He believes: “Implanting stents for patients with stable angina is caused by the superficial understanding of this disease in the 20th century. If a simple catheter is blocked, it will be fine to unblock the blocked part. In fact, the pain of many angina patients comes from smaller blood vessels, not from blocked coronary vessels, but people always implant coronary arteries. Into the stent."
6 What are the risks of coronary stent implantation
Although stent implantation is safer, there are still certain risks.
According to the current research, the mortality rate of coronary stent implantation is about 1%; the mortality rate of coronary artery bypass surgery is about 2%.
Because atherosclerosis is soft, plaque is hard, and the hardness of the junction between the two is medium, the stent cannot allow these obstructions of different hardness to be uniformly stressed, which may cause the blood vessel wall to crack or even rupture.
Also, some stents have a tendency to rebound, which will cause the stent to move and block the blood vessel again.
The mesh structure of the stent makes the inner wall of the blood vessel uneven, which in turn increases the risk of the blood vessel being blocked again or completely blocked.
Studies have shown that 30%-60% of patients re-narrow the blood vessels to the previous level after stent implantation, and some are even more severe. Most of this happens between 6 weeks and 6 months after stent implantation. This phenomenon is called "postoperative restenosis of blood vessels".
Most research reports believe that the restenosis rate of implanted bare metal stents is 20%, and the restenosis rate of implanted drug-eluting stents is 10%.
However, a recent study by the US Food and Drug Administration believes that implantation of drug-eluting stents is more likely to form thrombus and even sudden cardiac death than implantation of bare metal stents.
The stent is a foreign substance of human tissues, and the human immune system will treat it as a foreign invasion to resist, thereby forming new siltation at the stent site. Therefore, after the stent is implanted, it is necessary to take anticoagulant drugs, such as aspirin or clopidogrel for a long time. Gray, etc., reduce the activity of platelets and inhibit the formation of fibrous tissue in the inner wall of blood vessels.
In short, a responsible doctor should clearly explain the advantages and disadvantages of stent implantation to the patient, weigh the pros and cons, and decide whether to implant a stent.
The public should also learn more about the common sense of stents and do not mistakenly think that stent implantation cures coronary heart disease or angina pectoris.