Complications after coronary stenting

Stenting of the heart vessels is considered one of the most reliable operations, allowing to restore blood flow in a stenotic vessel. This, in turn, positively affects the work not only of the heart itself but also of other organs that, together with the blood stream, receive oxygen and nutrients necessary for their normal functioning.

The main advantage of the method of coronary stenting is low-trauma surgery. After all, it is not necessary to make incisions in the thorax and denude the heart, which is considered very dangerous with a high risk of death. And the recovery period after the same shunting operation is much longer, plus it is heavier.

A low-invasive stenting procedure rarely has negative consequences. Mortality of such operations is in the range of 1-1.5%, which is considered low, and the risk of complications rarely exceeds 2% (most often vascular complications). It is clear that the presence of pathologies listed in the paragraph describing the relative contraindications to surgery, somewhat worsens the prognosis, resulting in an increase in the number of deaths and the likelihood of complications.

The risk of a lethal outcome increases if the operation is performed with myocardial infarction in combination with cardiogenic shock or it is a question of tandem stenosis, which increases the complexity and time of the operation.

As we mentioned, complications of stenting of coronary vessels are rare, but they still need to be known. Some of them may occur in the coming days and weeks after the operation, others remind themselves about six months or more later. Early postoperative complications, taking into account the fact that operations are performed even in people with serious health pathologies, occur in 3-4 patients out of 100.

What are the immediate complications of coronary stenting that can be diagnosed in operated patients or during surgery:

• damage to the vessel during stent placement, internal bleeding,
• heart attack,
• stroke,
• allergic reactions or intolerance reactions arising in response to the administration of contrast,

• the formation of a hematoma at the site of puncture of the tissues of the thigh or arm caused by a hemorrhage from the damaged artery,
• severe bleeding from the wound, which is usually diagnosed in the event of a clotting disorder or when the requirement to limit physical activity is not complied with,
• failures in the work of the central nervous system and kidneys due to impaired cerebral or renal circulation,
• infection of the wound and the penetration of infection into the bloodstream,
• thrombosis of blood vessels (a "bare" stent creates unevenness on the vessel wall, as a result of which thrombi can actively adhere to it, although this process can be prevented if a drug-coated framework is used).

The likelihood of such complications increases in the following cases:

• The presence of the patient's allergic reactions in the anamnesis,
• metabolic disorders (diabetes, obesity),
• problems with coagulability of blood,
• recently suffered severe lung and heart disease (pneumonia, arrhythmia attack, heart attack, etc.),
• pathology of the kidneys,
• elderly age,
• Bad habits, for example, smoking.

A distant complication that can not be completely avoided even with the innovative stenting method is restenosis of the coronary arteries about six months after the operation (and sometimes much earlier). Restenosis is the repeated reduction of the lumen of blood vessels, as a result of which blood circulation in them is disturbed.

Restenosis can develop for 3 reasons:

• thrombus formation (drug-eluting stents solve this problem),
• a decrease in the lumen of the vessel (a complication inherent in balloon angioplasty, but the introduction of the stent creates a stable skeleton and does not allow the walls of the vessel to bend inward, changing the shape of the vessel)
• hyperplasia or proliferation of epithelial intimal tissues (inner shell) of coronary vessels.

The latter reason just causes restenosis inside the stent. At the same time, none of the methods for solving the problem today provides a positive result, which reduces the risk of developing such a complication, which according to statistics is about 20-40%.

The risk factors for the development of restenosis doctors call:

• hereditary predisposition to increased proliferation of vascular tissues,
• metabolic disorders, for example, diabetes mellitus,
• the large size of the stenotic area,
• discrepancy between the size of the stent and the parameters of the damaged portion of the vessel (in case of urgent operations, the doctor does not have the opportunity to select the right stent exactly, so use the available stents).

About carrying out of coronary stenting doctors can use various kinds of stents:

• non-coated metal products (BMS is the simplest and most ancient type of stent that does not protect against the formation of the carcass and restenosis with increased proliferation of neointima)
• products, the outer part of which, adjacent to the walls of the vessels, is covered with drugs preventing the proliferation of cells (DES - modernized stent, which prevents intimal hyperplasia, but does not reduce the risk of thrombosis),
• bioengineering products (BES - stents, the coating of which contains antibodies that prevent the formation of thrombi in the early and late period after surgery),
• biodegradable (decomposing inside the vessel) products (BVS - drug-eluting stents that block the proliferation of connective tissue inside the vessel),
• products with a double drug coating (DTs - the newest model of a stent, which significantly reduces the risk of thrombosis and proliferative reactions).

Studies have shown that the use of drug-eluting stents reduces the likelihood of early and distant complications by about 20-25%. Thanks to such products, coronary stenting is today considered to be the most effective method of restoring the patency of the heart vessels.

[1], [2], [3], [4], [5], [6]