Home Therapies Stent: definition, reasons, process and risks

Stent: definition, reasons, process and risks

by Josephine Andrews
Published: Last Updated on 348 views

stent is a vascular support made of metal or synthetic fibers that is inserted into vessels or hollow organs to support them and keep them open. It is usually a tubular, small lattice framework. Read all about stenting, how it works and the risks. 

What is a stent?

A stent stabilizes narrowed vessels after they have widened. The aim is to prevent blood vessels from occluding again. In addition, the stent made of metal or synthetic fibers fixes vascular deposits, smoothes the surface of the vascular interior by being pressed against the vascular wall, and thereby improves blood flow in the vessel. The most common variant is the “heart stent” on the coronary arteries, which is used in patients with coronary heart disease. Here, the stent has now replaced the bypass operation. With the help of a thin plastic tube (catheter), the surgeon places the stent, which can be tightly compressed thanks to its fine-meshed lattice structure. There are different types.

Self deploying stent

The self-expanding stent consists of a steel mesh mesh and is surrounded by a plastic sleeve. After the surgeon inserts it through the catheter into the stenosis, he pulls back the sheath and the stent unfolds.

Balloon Expanding Stent

The folded stent is placed on a so-called balloon catheter, which can be inflated as part of a vascular dilation, known as percutaneous transluminal angioplasty (PTA). The metal mesh of the stent then retains the expanded shape.

Coated stents

In addition to uncoated stents (bare metal stents, BES), drug-coated stents (drug eluting stents, DES) are now being used more and more frequently. The drugs released prevent new cell formation and thus counteract renewed occlusion (re-stenosis). Research is also being carried out into completely bioresorbable scaffolds (BRS), which degrade after some time, for example to avoid the risk of blood clots blocking the stent the longer it remains in the stent.

Two types are currently being tested: magnesium-based stents (dissolve after approximately 1 year) and biopolymer stents (residual three to four years). A few years ago, the first BRS stents (known as “bioabsorbable vascular scaffolds”, BVS) came onto the market. However, some studies have shown that with these BVS, among other things, more blood clots and thus renewed blockages occurred, so that the manufacturer took their stents off the market again in the summer of 2017. Current and reliable data on the new stent developments are still missing. They are actually only used in the context of studies.

When is a stent implantation performed?

A stent is always used when permanent expansion of an occluded vessel or hollow organ cannot be guaranteed simply by widening the vessels (percutaneous transluminal angioplasty, PTA).

This is most common in the following situations:

How do vessels close?

The main reason for vascular occlusion is hardening of the arteries ( arteriosclerosis , atherosclerosis). So-called plaques are formed as a result of various processes. These constrict the vessel. In addition, the mechanical stress causes the smallest injuries and bleeding. If a clot of blood platelets (thrombus) forms on the torn plaque, it can occlude the vessel.

A blood clot (thrombus) can also block a vessel without arteriosclerosis. Three factors (Virchow’s triad) are responsible for the formation of a thrombus: a change in blood composition, a slowdown in blood flow and changes in the vessel walls. A so-called embolism can also cause a vascular occlusion. In the process, thrombi detach from their original location and enter narrower vessels via the bloodstream, where they cause the occlusion. However, a stent does not usually have to be used for such thromboembolic events.

What do you do with a stent implantation?

The stent operation (stenting) is a so-called minimally invasive procedure and only requires the smallest incisions. As with any operation, the doctor will carry out some standard examinations beforehand. These include an electrocardiogram ( ECG ) and a blood draw . If the coronary arteries are blocked, an additional stress ECG , an X-ray of the lungs and heart and possibly an examination of the blood flow in the heart muscle (myocardial scintigram) are necessary. In addition, the doctor advises the patient in detail and enlightens him. In order to be able to inject iodine-based contrast media for X-ray examinations, an iodine allergy must be ruled out.

First, after local anesthesia, the doctor pierces a blood vessel close to the surface, usually the arm or groin artery, and inserts a “sluice”. Under X-ray control, he pushes a special catheter over this to the constriction of the blocked vessel and injects contrast medium to show the constriction again.

In PTA, a collapsed balloon is placed at the tip of the catheter. As soon as this is placed at the constriction, it is filled with a mixture of saline and contrast medium and expands. The balloon presses the deposits and calcifications against the vessel wall, thereby opening the vessel.

If a stent needs to be placed, doctors also guide it to the narrowed vascular site using their own catheter. There the stent either unfolds itself (eg in the case of carotid stenosis) or is pushed open by a balloon. The stent then prevents blood vessels from occluding again.

Once the stenting is complete, the doctors remove all catheters and the sheath and apply a pressure bandage . This must remain for a few hours.

What are the risks of stent implantation?

In addition to the general surgical risks such as infections, wound healing disorders and minor bleeding, the following complications can occur in rare cases:

  • Cardiac arrhythmias during the procedure
  • vascular occlusion
  • Vessel perforation with life-threatening blood loss
  • heart attack or stroke
  • Stent thrombosis: The stent is blocked by a blood clot

Ultimately, the complications depend heavily on the site of the stent implantation. The patient’s previous illnesses also influence the complication rate.

What do I have to consider after a stent implantation?

The patient is usually discharged the day after the stenting after an electrocardiogram and blood tests have been carried out to monitor it. To prevent blood clots, the doctor prescribes two “blood-thinning” drugs that prevent the platelets from clumping together (platelet aggregation inhibitors). Both medications should be taken for six to twelve months after a stent has been implanted in the heart, after which one (usually ASA) is sufficient.

Within the first few weeks after the stent operation, a doctor will examine you again thoroughly. He listens to the heart and lungs and carries out various tests, such as a resting ECG, blood pressure measurements and laboratory tests. They are repeated at regular intervals.

life with stent

A stent does not restrict you in everyday life. Examinations such as magnetic resonance imaging (MRT) are also possible. Quitting smoking, regular physical activity, and a balanced diet are helpful in preventing plaque-related vasoconstriction. If you can manage the risk factors for atherosclerosis, you may not need a new stent .

Sports with stents

Sport can improve the course of the disease and the prognosis of heart disease. Through regular training, the patient increases their fitness and can exercise more without symptoms occurring. This significantly increases the quality of life.

Regular physical activity has the following positive effects on the body:

  • improves the oxygen supply to the body
  • lowers blood pressure
  • regulates blood sugar levels
  • regulates blood lipid levels
  • Reduction of fat deposits
  • counteracts inflammatory processes
  • promotes healthy body weight
  • reduces stress hormones

A stent is not an exclusion criterion for sport. The stent does not cause any restrictions. However, it is important to choose a sport that does not put excessive strain on the cardiovascular system and is adapted to the underlying disease.

Moderate endurance training is particularly suitable for most cardiac patients. This includes, for example:

  • (quick) walk
  • Walk on a soft mat/sand
  • hike
  • Walking and Nordic walking
  • jog
  • cross country skiing
  • step aerobics
  • cycling or ergometer training
  • Climbing stairs (eg on the stepper)

Cardiac patients should be active and do endurance sports three to five times a week, 30 minutes each time.

Entry into training after stent surgery

How long to spare after a stent is placed? That depends on the underlying condition. After a mild heart attack, the person affected can usually slowly become active again after about a week. After a severe heart attack, however, he is treated in the hospital for a longer period of time. This is where the first therapeutic mobilization usually begins.

Note: You should always discuss starting training with your doctor if you have a heart condition. He knows your case and your physical constitution and can give you a recommendation.

At the beginning of the training it is important to start with a low intensity and slowly increase it.

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