In-stent restenosis

Definition

In-stent restenosis is a repeated narrowing of the vessel lumen after percutaneous intervention. The complication mainly occurs in the case of concomitant metabolic and cardiovascular diseases, the use of outdated stent models, and the violation of the manipulation technique. The condition is manifested by typical symptoms of angina pectoris: attack-like chest pain, shortness of breath, and heart palpitations. To diagnose restenosis, coronary angiography, ECG, and echocardiography, laboratory studies of the level of glucose, lipoproteins, and myocardial markers in the blood are performed. Treatment involves repeated endovascular intervention to restore the vessel lumen.

General information

Stent restenosis occurs in 10-40% of patients undergoing percutaneous stenting. Most often, it is localized in the coronary arteries. The frequency of pathology depends on the product’s material, the procedure’s technique, and the patient’s somatic status. Elderly patients are at greatest risk, who often have comorbidities that affect the state of the vascular wall. Given the wide use of percutaneous coronary interventions (PCI) for the treatment of CHD, the problem of stent restenosis is one of the most urgent in modern cardiac surgery.

Causes

In interventional cardiology, restenosis is recognized as a multifactorial pathology that depends equally on the quality of the manipulation, the initial clinical situation, and the patient’s general health. To calculate the probability of complications after percutaneous intervention for a particular patient, the following risk factors are taken into account:

• Stent material. The risk of restenosis reaches 41% when using bare-metal stents (BMS) while drug-eluting stents (DES) reduce the probability of pathology by four times. At the same time, drug-coated products increase the risk of neoatherosclerosis with unstable plaques, which also cause vessel narrowing.
• Peculiarities of PCI. The probability of recurrent stenosis increases with the simultaneous placement of several stents, the stenting of a vessel over a long length, and the need to overlap stents. The cause of the problem may be errors during manipulation, traumatization of the arterial wall, or incomplete stent deployment.
• Peculiarities of the vascular lesion. The complication is often observed during PCI in the arterial orifice or at the bifurcation site, where the vascular wall is subjected to maximal hemodynamic load. The predictor of stent restenosis is multiple lesions and involvement of small vessels.
• Presence of diabetes mellitus. Carbohydrate metabolism disorders are the main risk factor associated directly with the patient. Hemodynamically and clinically significant restenoses are observed in 28% of patients with type 2 diabetes and in 16.3% of patients with type 1 diabetes. The high frequency of complications is explained by endothelial dysfunction and prothrombotic state on the background of hyperglycemia.
• Constitutional factors. The risk of stent restenosis increases as the patient’s age increases. Although men are more prone to cardiovascular events that require endovascular treatment, complications after PCI are more common in women. An independent risk factor is a hereditary predisposition to cardiovascular pathologies.

Classification

In practical cardiac surgery, there are several approaches to systematizing the disease. In practice, the division of restenosis by the time of its occurrence into acute (develops in the first 24 hours after PCI), subacute (1-30 days), late (1 month – 1 year), very late (12 months and more) is mainly used. The Mehran classification of restenosis is widely known and includes four classes:

• Class I (localized). Stenosis areas occupy a small area of the installed stent and may occur in different locations: between two structures (type A), at one of the edges (type B), in the middle of the stent (type C), and multifocally (type D).
• Class II (diffuse). Intimal hyperplasia and vessel narrowing occur throughout the stented part of the artery but do not extend beyond it.
• Class III (diffuse proliferative). Tissue hyperplasia and zones of neoatherosclerosis extend beyond the stent, affecting neighboring areas of the arterial wall.
• Class IV (occlusion). The most severe form of restenosis occurs when complete occlusion of the vascular lumen occurs, and blood flow in this area stops.

Symptoms of stent restenosis

Repeated narrowing of the vascular lumen manifests classic signs of angina pectoris, which bothered the patient before PCI. Compressive pains in the left side of the chest, associated with physical or psychoemotional load, last up to 20 minutes and are controlled by usual medication doses. Patients feel shortness of breath, headaches, dizziness, and constant weakness

in the interictal period.

There is no symptomatology in some patients, so the problem is detected during control coronarography as part of a cardiologist’s medical examination. The absence of clinical manifestations is associated with the active development of collateral circulation, characteristic of people with a long history of coronary heart disease. Neuropathy in diabetes mellitus also contributes to the painless form of restenosis.

Diagnosis

Complaints of heart pain after cardiac surgery are an indication for immediate consultation with a cardiologist. Diagnosis will require a detailed study of medical records, PCI peculiarities, and standard physical examination to assess the cardiovascular system. To confirm stent restenosis, such methods are prescribed:

• Angiography. The study of vessels with contrast is the “gold standard” for diagnosing PCI complications. It provides detailed information about the localization of the problem, the current diameter of the vascular lumen, and the endothelial state in the stenting area and other parts of the coronary arterial network.
• Intravascular ultrasound. This innovative method of IVUS with virtual histology technology quickly and accurately diagnoses neoatherosclerosis and intimal hyperplasia in the area of the stent. The technique visualizes all pathomorphological changes, including calcification and thrombosis.
• Cardiac ultrasound. Echocardiography is prescribed to study myocardial contractility, assess cardiac output, and determine the state of the main vessels. Ultrasound diagnostics is supplemented with ECG to study the heart rhythm and detect signs of myocardial ischemia or necrosis.
• Laboratory studies. Signs of acute coronary syndrome with restenosis require analysis for myocardial markers and acute-phase indices. All patients undergo a biochemical study of blood with a lipidogram, assessment of glucose and glycated hemoglobin levels, and coagulogram.

Treatment of stent restenosis

Surgical treatment

The effectiveness of drug anti-inflammatory therapy is not confirmed by scientific studies, so the only method of correction of vascular pathology is endovascular intervention. Elimination of restenosis is indicated when the arterial lumen is reduced by 70% or more from the norm, vessel narrowing by 50-70% in combination with obvious clinical signs of angina pectoris.

According to the recommendations of the European Society of Cardiology, most patients should undergo repeat PCI and a new type of drug-eluting stent or balloon angioplasty combined with stenting. In case of recurrent episodes of restenosis, multivessel lesions, or large arterial narrowing, aortocoronary bypass surgery is considered.

All these treatment options are available in more than 650 hospitals worldwide (https://doctor.global/results/diseases/in-stent-restenosis). For example, Percutaneous coronary intervention (PCI) with stent insertion can be done in these countries for following approximate prices:

Turkey $8.1 K in 25 clinics

Israel $15.6 K – 17.4 K in 12 clinics

Germany $26.3 K in 34 clinics

China $27.3 K in 3 clinics

United States $41.3 K – 108.6 K in 13 clinics.

Rehabilitation

After repeat PCI, patients are monitored by a cardiologist and undergo regular check-ups to prevent restenosis and thrombosis. For prophylactic purposes, antithrombotic therapy, which includes antiplatelet and anticoagulant drugs, is prescribed. A hypocholesterolemic diet, restriction of foods with a high glycemic and insulin index, and feasible physical activity without overexertion are recommended to reduce the risk of complications.

Prognosis and prevention

Restenosis with hemodynamic disturbances in coronary vessels is recognized as prognostically unfavorable because it sharply increases the overall cardiovascular risk. However, such problems can be avoided with timely repeated PCI. Preventing the condition requires the rational choice of angina treatment tactics, the use of high-quality stents of the latest generation, and the elimination of modifiable risk factors on the part of the patient.