Medical stents are important stent-type medical devices in modern minimally invasive interventional medicine.
Their main principle is to insert a tubular mesh structure into narrowed or blocked cavities (such as blood vessels, esophagus, bile ducts, etc.) through a catheter, and then expand them to restore patency and normal physiological transport function.
I. Core Clinical Application Areas Medical stents can be classified into the following categories according to the application site and department:
1. Cardiovascular System (most common application): Coronary artery stents. Indications: Used to treat coronary heart disease, angina pectoris, or acute myocardial infarction.
Mechanism: Expands the coronary arteries narrowed by plaque buildup, reconstructing blood flow.
Types: Divided into early bare-metal stents, the currently mainstream drug-eluting stents (with drugs on the surface to inhibit excessive endothelial cell proliferation to prevent re-blockage), and cutting-edge biodegradable magnesium alloy stents (which dissolve naturally after fulfilling their support function, leaving no foreign body).
2. Peripheral Vascular System. Indications: Used for carotid artery stenosis (to prevent stroke), lower extremity arteriosclerosis obliterans, or aortic aneurysms, etc.
Mechanisms: 1. **Stent Grafts:** Stent grafts can be used to isolate aortic aneurysms and prevent rupture; conventional stents are used to open peripheral blood vessels and improve limb ischemia.
2. **Digestive System:** Gastrointestinal stents are indicated for malignant intestinal obstruction or esophageal stricture caused by esophageal cancer, gastric cancer, colorectal cancer, etc.
Mechanisms: Relieve dysphagia or constipation, improving the ability to eat and the quality of life in advanced-stage patients.
3. **Urogenital System:** Ureteral and urethral stents are indicated for acute obstruction, tumor compression, or stricture caused by ureteral stones.
Mechanisms: Implanted tubular stents support the ureter, protect kidney function, and drain urine; this is one of the earliest applications of stents.
4. **Respiratory System:** Tracheal stents are indicated for tracheomalacia or airway stricture caused by compression from lung cancer, tuberculosis, etc.
Mechanisms: Prevent tracheal collapse and relieve breathing difficulties.
II. Evolution of Stent Materials and Technology With advancements in biomaterials science, modern stents have evolved from passive support to biocompatible designs:
Traditional Metal Stents: Primarily use stainless steel or nickel-titanium alloys with shape memory function; these are permanent implants.
Drug-Coated Stents: The surface is coated with specific drugs, significantly reducing restenosis rates after vascular implantation.
Bioabsorbable Stents: Made of polymers or magnesium alloys. Within several months to one to two years after implantation, the stent is gradually broken down and absorbed by the body, restoring the blood vessel's natural elasticity.
III. Postoperative Precautions
Medical Treatment: After stent implantation, it is usually necessary to strictly follow the doctor's instructions to take dual antiplatelet drugs (such as aspirin, clopidogrel, etc.) to prevent thrombosis within the stent.
Follow-up and Lifestyle: Maintain a healthy lifestyle after surgery (quit smoking, control blood pressure and blood lipids, regular exercise). Generally, daily activities and air travel are not affected after recovery.
