Cardiac stents can be removed

Stent placement


Vascular constriction treated with a stent © crevis / Fotolia

With a stent - too Stent called - it is a small tube made of wire mesh that is inserted into a vessel to keep it open. Constrictions of the coronary arteries are treated with stent implantation. In addition, a stent can also be used in the area of ​​the aorta (main artery). In the majority of the treatments (approx. 75%) of constrictions that are carried out today, one or more stents are used to keep the vessel open, similar to the way a tunnel also has to be supported.

Stent implantation in the area of ​​the coronary arteries

When is a stent used in the coronary artery area?

Vascular aging processes, which are accelerated by various risk factors such as smoking, a high-cholesterol diet or diabetes, lead to deposits in the coronary arteries (coronary plaques). If they reach a certain size, one is created Constriction of the coronary artery (Stenosis) and the blood flow to the heart muscle is reduced. The treatment of such constrictions can also be carried out by means of stent implantation in addition to balloon expansion.


Insertion of a stent after the PTCA

How does stent implantation work in the area of ​​the coronary arteries?

The process of stent implantation is initially very similar to the process of cardiac catheterization and PTCA. After puncturing the Inguinal artery becomes a catheter against the flow of blood to the heart and inserted into the opening of the coronary artery. Smaller catheters are then advanced through the interior of this catheter into the coronary artery to expand the constriction. Therefore this catheter is also referred to as a guide catheter. First of all, a very thin, flexible wire must be passed through the constriction under X-ray control.

The stent is mostly made of stainless steel and is initially folded up. When folded it is on a Balloon catheter pushed open and fastened. As a rule, the stent is now already preassembled on the balloon during manufacture. The The balloon serves as a carrier for the stent, through which the stent is later positioned in the constriction and deployed. While the balloon is deflated and withdrawn after approx. 10-30 seconds, the stent remains fully deployed in the coronary artery and holds the vessel open.

The stent is a foreign body. Until it has healed, additional medication must be taken every day to prevent blood clots from forming on its surface (e.g. Plavix, Iscover, or Tiklyd). As a rule, a stent has healed enough after 30 days for the drug to be discontinued. However, certain types of stents that are covered with a plastic membrane only heal slowly, so that they may need to be taken for 6 to 12 months.

What happens in the coronary artery area after stent placement?

After the stent implantation, the sheath in the groin is removed either immediately or the next day and the puncture site is closed; this depends on the respective center. This is followed by monitoring on the (intensive) ward using an EKG and blood tests. If thoracic complaints recur, you should inform the doctor immediately. A Discharge is usually possible the next dayprovided that no complications have arisen.

Normally 6 months after stent implantation, a check-up with a cardiac catheter is recommended, as re-constrictions due to excessive “scarring” within the stent, similar to PTCA, can occur in 10-30% of all cases. If new heart problems occur within these 6 months, an early check-up may be necessary. If there is a re-narrowing, it may be necessary to rework by expanding the balloon again. If the expansion result is good, the treatment is complete. The daily intake of ASA (Aspirin®) should be continued for life. Another cardiac catheterization is only required if heart problems recur.

What alternatives to stenting are there for coronary artery narrowing?

In addition to stent implantation, coronary artery constrictions can also be treated using balloon expansion, laser angioplasty or rotablation. However, if all three coronary arteries are narrowed or the narrowing is unfavorable, e.g. in the area of ​​the main branching of the coronary arteries, a bypass operation must be performed by the cardiac surgeon.

What complications can arise when stenting in the coronary artery area?

Possible complications include Heart pain during stent placement as well as cardiac arrhythmias. In rare cases (<2%), the stent may detach from the carrier balloon and be carried over into the arteries of the head or extremities, as well as acute occlusion of the stent (stent thrombosis) due to the formation of clots with the development of a heart attack. To avoid this complication, an additional medication (e.g. Plavix ®, Iscover® or Tiklyd®, see above) must be taken daily for 30 days.

Furthermore you can Inguinal artery complications or Hypersensitivity reactions to the contrast agent, similar to what occurs during cardiac catheterization.

What future prospects exist in the field of stents (vascular supports)?

In the near future, stents will be available that have certain drugs on their surface, so-called coated stents, which are intended to prevent excessive scar formation in the stent. This is intended to reduce the rate of re-constriction, especially in patients with a high risk of re-constriction.


Stent placement in the area of ​​the aorta

Background information on the aorta

The aorta (main artery) is the largest artery in the body. It originates directly above the heart valve of the left main chamber. The aorta carries the blood from the heart and distributes it through further divisions to the brain and the individual body organs.

Different sections of the aorta are distinguished. The ascending part of the aorta goes directly from the heart chamber. The aortic arch follows; the main artery here takes a crutch-like arch and bends in the direction of the lower half of the body. The vessels for the head and neck branch off from the aortic arch. This is followed by the descending part of the aorta, which in turn is divided into a section located under the ribs, in the chest (thoracic artery) and the abdominal aorta. The arteries for the viscera such as the liver, spleen, pancreas and intestines go off in the abdomen. Finally, the aorta divides into the two leg arteries in the lower section (approximately at the level of the navel).

When is a stent implantation performed in the aorta area?

High blood pressure and / or changes in the vascular wall can lead to bulges (aneurysms) in the main artery. In addition to these, you can also Tears in the vascular lining that arise to a Splitting of the vascular pathway with the formation of two canals (dissection). These diseases lead to an expansion of the main artery. If the diameter exceeds a critical limit (more than 5.5 cm), the risk of a sudden burst (rupture) of the aorta increases significantly. Patients can bleed to death within a short period of time. To avoid a rupture, symptom-free patients whose aorta is more than 5.5 cm in size or with an increase in size of more than 1 cm per year have been subjected to preventive surgery. Operations on the main artery, however, represent extensive interventions that are associated with a not inconsiderable mortality and complication rate. In the case of diseases of the thoracic artery, an opening of the thorax is also necessary.

Recently it stands with the so-called endovascular aortic stenting a new, gentler therapy alternative is available. This enables the treatment of diseases of the descending part of the thoracic artery and the abdominal artery. Diseases of the ascending part of the aorta near the heart still have to be treated with open surgery.

A vascular support provided with an impermeable plastic membrane can seal out sacs in the aorta and tears in the vascular lining. This relieves the excessively widened section of the vessel. The scarring and coagulation of the blood remaining in the sac also strengthens the thinned vascular wall. An opening of the body cavity is not necessary for the stent implantation in the area of ​​the aorta, the stent is inserted via the groin. The procedure is therefore much less stressful than an operation. For this reason, patients at high risk for open surgery can also be treated with aortic stent implantation.

How does stent implantation work in the aorta area

The initially folded stent is placed over a Catheter from the groin into the main artery brought in. The procedure is usually carried out in general anesthetic. Since the aortic stents (approx. 3-4 cm in diameter) are significantly larger than the stents (approx. 3 mm) that are used in the treatment of constrictions of the coronary arteries, the catheter in which the folded aortic stent is located can, due to its Size usually cannot be introduced via a vascular puncture. Surgical exposure of the inguinal artery is required through an approx. 5 cm skin incision in the groin region.

The stent is introduced into the diseased section of the aorta via a catheter under X-ray control and then released. When placing the aortic prosthesis, the control by means of cardiac ultrasound, which is carried out from the esophagus, is also very useful. During the implantation of the aortic stent, the blood pressure must be lowered in order to be able to implant the stent precisely.

The result is checked with an X-ray contrast agent immediately after the implantation. The opened inguinal artery and the skin incision are then sutured. After the aortic stent implantation there is usually one Requires 24-hour monitoring in the intensive care unit.

What complications can arise when stenting in the aorta?

Possible complications of stent implantation in the aorta include injuries to the vascular nerves in the groin, wound healing disorders in the groin, hypersensitivity reactions to the contrast agent and inflammatory reactions to the aortic stent.

Rare complications of stent implantation in the aorta are the obstruction of the left arm artery by the aortic stent and paraplegia. If the aortic stent implantation does not succeed, it may be necessary to switch to open surgery.

Authors:
Dr. med. Eggebrecht
Prof. Dr. med. R. Erbel