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A coronary stent is a stent placed in the coronary artery that supply blood to the heart, to keep the arteries open in patients suffering from coronary heart disease. The vast majority of stents used in modern interventional cardiology are drug-eluting stents (DES). They are used in a medical procedure called percutaneous coronary intervention (PCI). Coronary stents are divided into two broad types: drug-eluting and Bare-metal stent. As of 2023, drug-eluting stents were used in more than 90% of all PCI procedures. (2018). 9780323555937, Elsevier/Saunders. ISBN 9780323555937 Stents reduce angina (chest pain) and have been shown to improve survival and decrease adverse events after a patient has suffered a heart attack—medically termed an acute myocardial infarction. (2017). 9781259584732, McGraw Hill Medical. ISBN 9781259584732
Similar stents and stenting procedures are used in atherosclerosis of arterial vessels of the limbs—particularly in the legs, such as in peripheral artery disease.
Patients not undergoing primary PCI are usually awake during the placement of a coronary stent, though local anesthetics are used at the site of catheter entry, to ensure there is no pain. In reality practices vary, though patient comfort is a priority. Various techniques of pain management and anesthesia are practiced during current PCI stent placement procedures.
The catheter/stent system is introduced into the body by penetrating a peripheral artery (an artery located in the arm or leg) and passed through the arterial system to deliver the DES into the blocked coronary artery. The stent is then expanded to dilate (open) blocked or narrowed coronary arteries (narrowed by plaque buildup), caused by a condition known as atherosclerosis. Peripheral arterial access is usually via the femoral (upper leg) or the radial artery (arm/wrist) and less commonly performed via the brachial or ulnar artery (wrist/arm). Historically, controlling bleeding at the point of arterial access after the procedure was an issue, modern arterial pressure bands and arterial closure system now exist which have helped control post procedure bleeding, but bleeding after the procedure is still a matter of concern.
The 'stent tube mesh' is initially 'collapsed' onto the catheter, that catheter contains an inflating balloon component. In this collapsed state, it is small enough to be passed though 'relatively' narrow arteries and then inflated and compressed firmly against the diseased artery wall, by air pressure introduced via the still attached catheter, inflation time and pressure are recorded during this placement procedure. Consider an umbrella metaphor, initially unopened and then opened.
Many significant treatment decisions are made in real time during the actual stent placement, the Interventional Cardiologist uses Intravascular ultrasound (IVUS) and Fluoroscopy imaging data to assess the exact location, the true occlusion status. A radiopaque contrast dye is passed through the catheter and is used to visualize the arteries and evaluate the location of the narrowed vessel. This information is used in real time to decide how best to treat the occlusion(s). Information regarding the health and anatomy of the broader coronary blood supply can also be evaluated; as coronary vasculature varies from individual to individual. This data is captured on video and is valuable if any further treatments of a patient are necessary.
As a stent/DES is a medical device, patients are given a 'medical device card' with information on the implanted DES and a medical device serial number; this is important and is useful in future potential medical procedures. This is also the case of several arterial closure systems which are also medical devices. There is usually soreness at the point of entry into the arterial system, and fairly large (significant bruising) are very common. This soreness usually improves after a week or so. Usually, patients are advised to 'take it easy' for a week or two and are instructed to be cautious not to lift any substantial weights. This is primarily to ensure the access site heals. Follow up appointments within a week or two of the procedure with a cardiologist or primary care provider/GP are a standard practice.
It is a standard practice to have further follow-up examinations every three to six months for the first year, though these practices do vary. Further diagnostic coronary angiography is not routinely indicated after coronary stent implantation. If progression of heart disease is suspected, a stress test could be performed; patients who develop symptoms or show evidence of ischemia in a stress test may undergo diagnostic cardiac re-catheterization.
Physical examinations play an important role after PCI-stenting procedures. Those patients at high risk of suffering from complications and those with more complexed coronary issues, angiography may be indicated regardless of the findings of non-invasive stress tests.
Cardiac rehabilitation activities are dependent on many factors, but largely are connected to the degree of heart muscle damage prior to the PCI/DES procedure. Many patients who undergo this procedure have not had a heart attack, and may have no notable damage to their hearts. Others may have had a heart attack and the amount of damage to their heart's ability to supply the body with oxygenated blood might be grossly impaired. Rehabilitation activities are prescribed to fit each individuals needs.
However, in some cases the dual antiplatelet therapy may be insufficient to fully prevent clots that may result in stent thrombosis; these clots and cell proliferation may sometimes cause standard (“bare-metal”) stents to become blocked (restenosis). Drug-eluting stents were developed with the intent of dealing with this problem: by releasing an antiproliferative drug (drugs typically used against cancer or as immunosuppressants), they can help reduce the incidence of "in-stent restenosis" (re-narrowing). A 2017 Cochrane review comparing bare-metal and drug-eluding stents found that the latter may result in reduced incidence of serious adverse events. However, at maximum follow up, it found no difference between the two on cardiovascular mortality and myocardial infarction.
The "vast majority of heart attacks do not originate with obstructions that narrow arteries." Further, “researchers say, most heart attacks do not occur because an artery is narrowed by plaque. Instead, they say, heart attacks occur when an area of plaque bursts, a clot forms over the area and blood flow is abruptly blocked. In 75 to 80 percent of cases, the plaque that erupts was not obstructing an artery and would not be stented or bypassed. The dangerous plaque is soft and fragile, produces no symptoms and would not be seen as an obstruction to blood flow.” The use of statins to create more stable plaques has been well studied, and their use along with both PCI/Stenting and anticoagulant therapies is considered a broader treatment strategy.
Some cardiologists believe that stents are overused; however, in certain patient groups, such as the elderly, studies have found evidence of under-use.
Several other clinical trials have been performed to examine the efficacy of coronary stenting and compare with other treatment options. A consensus of the medical community does not exist.
In development are stents with biocompatible surface coatings which do not elute drugs, and also absorbable stents (metal or polymer).
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