What is a stent?
The stent or endoprosthesis is a cylindrical tool with meshes of various sizes that is inserted and widened in hollow organs to support the internal walls, or to maintain their shape and function intact. This instrument is made of elastic and biocompatible materials that ensure that it is positioned in place without being traumatic to the blood vessels, as well as ensuring that the structure is absorbed without the possibility of rejection.
There are several models and brands of endoprosthesis to adapt to the characteristics of each surgery and the patient’s needs.
The endoprosthesis is designed to reinforce the venous wall and favor the correct blood supply to the organism. It is a minimally invasive surgery and is usually performed under general anesthesia, but it can also be performed under local anesthesia, depending on the duct and pathology to be treated.
Pathologies for which stents are used
Stents are mainly used in coronary diseases, or when fatty plaques accumulate inside these vessels, which compromises the flow of oxygenated blood to the heart and can cause a heart attack. The most frequent case of application is coronary artery disease, especially when the condition no longer responds to medication, but the situation is not severe enough to intervene with a bypass, i.e. there is no blocked coronary artery.
Stents are commonly used in coronary artery disease.
This technique is also used in the treatment of carotid disease in the same way. The stent is also used in the aorta, the most important artery in the human body, which can be affected by aortic aneurysm, an excessive dilatation of the vessel that causes internal bleeding. In this type of operation, however, the result is the opposite of coronary artery disease, as the instrument is inserted to cover the aneurysm and create a new pathway for blood flow. A few weeks after insertion, the stent is absorbed by the vessel walls and becomes the only pathway through which blood flows. Stents are not suitable for pulmonary veins, if a vessel has become too narrow, there are several blockages in the same vessel, or the myocardium is already damaged.
How is the stent placed?
The stent is placed under local anesthesia by a surgical operation, often minimally invasive. The procedure is also completely X-ray guided for accuracy. Through an incision in the femoral artery, a balloon catheter containing the stent is pushed into the affected area. The physician then inflates the balloon to get the stent to expand, reopening the blocked vessel and restoring blood flow. Once in place, the catheter and balloon are removed, leaving the stent in place. Occasionally, the specialist may also use a drug-eluting stent to block excessive cell growth called restenosis, which is a real complication.
Specialist using the stent
The specialist who evaluates stent placement is the cardiac surgeon.
Why is it performed?
It is usually inserted into the body through a small incision and is used to treat ducts that have been narrowed or blocked by disease. The ducts where it is most commonly used are aortic aneurysms, esophagus, bile ducts, trachea or bronchi.
In the case of aneurysms, the stent is introduced through a small incision in the groin and advanced through the femoral artery to reach the aorta and the area of the aneurysm to strengthen the vessel wall.
Placed in the esophagus, the stent is used to allow the passage of food; as well as in the bile ducts it is used to open the passage of bile into the intestine.
In the trachea and bronchi, the stent opens the vessel to allow normal breathing.
What does it consist of?
The surgery consists of making a small incision, usually in the groin, through which the stent is advanced by means of a catheter through the iliac vessel to the place where the stent is to be implanted. This procedure can be supported by a follow-up X-ray (fluoroscopy or computed axial tomography) or ultrasound so that the vascular surgeon specialist can control and verify the correct implantation of the stent.
Once the stent has been advanced to the ideal place to place the stent, the catheter is removed and the stent is well positioned inside the vessel, and the whole procedure usually takes about 2 hours.
The stent is introduced into the blood vessel to open it and reinforce its walls.
Preparation for the stent
Before surgery, the specialist may ask the patient to undergo some diagnostic imaging tests to observe the characteristics of the vessel to be treated. The clinical history will also be evaluated to see if the patient is a candidate for surgery. The patient may not be a good candidate for an endoprosthesis if he/she has irregularly shaped blood vessels, an aneurysm that is too large, some pathologies that do not allow him/her to endure a 2-hour surgery or is a pregnant woman.
Just before the surgery, the groin area where the incision is made will be cleaned and shaved, and local or general anesthesia will be applied. The patient may need to fast to receive the anesthesia.
Care after the procedure
Normally after the operation the patient will remain lying in a horizontal position for 4 to 6 hours while the wound heals completely. The hospital stay will last 2 to 4 days and depending on the case may need to be monitored overnight in an intensive care unit (ICU).
During the postoperative days the patient may experience discomfort in the groin, swelling in the thigh, prickling in the legs, fever and constipation.
Most stents require periodic check-ups to ensure that the treated vessel is functioning properly and the stent is in good condition.
Alternatives to stenting
Stenting is currently the most advanced and innovative procedure for repairing, opening and strengthening vascular conduits. The alternative to this procedure is conventional open surgery, which involves a larger incision and a higher risk of complications, as well as a longer postoperative period.