1.What is interventional therapy?
You may know about medication in internal medicine, surgery in surgery, radiation therapy in radiotherapy …… but you may not have heard of interventional therapy. What is interventional therapy? Interventional therapy is a minimally invasive treatment using modern high-tech means – under the guidance of medical imaging equipment, special catheters, guidewires and other precision instruments are introduced into the human body to diagnose and locally treat internal pathologies.
Interventional therapy applies digital technology, which expands the doctor’s field of vision and extends the doctor’s hands with the help of catheters and guidewires. Its incision (puncture point), which is only the size of a grain of rice, can treat many diseases that could not be treated in the past, had to be treated surgically or had poor efficacy of medical treatment, such as tumors, hemangiomas, and various bleeding, without cutting into human tissues. Interventional treatment has the characteristics of no incision, small trauma, fast recovery and good effect.
2.Indications for interventional therapy.
Embolization therapy in interventional treatment has a high cure rate for various benign tumors, such as hepatic hemangioma; it has an immediate effect on hemostasis for various bleeding diseases, such as hemoptysis and oral bleeding caused by bronchial dilatation or lung cancer, hemorrhage caused by obstetrical and gynecological diseases or postpartum, and internal bleeding caused by trauma, which has basically replaced surgical treatment. There are many “ducts” in the human body. In addition to the widely distributed blood vessels, there are also various ducts such as esophagus, trachea, bile duct, ureter and nasal duct.
The narrowing of human ducts can cause many diseases, such as blood vessel narrowing can cause hypertension, esophageal narrowing can cause dysphagia, biliary narrowing can cause obstruction jaundice ……, these narrowed ducts are difficult to unblock by taking medicine, and surgery is very traumatic and risky. Interventional treatment can use balloons to dilate the narrowed ducts, or metal stents can be placed in the duct lumen to create artificial ducts.
In the case of stenting for renal artery stenosis, for example, after puncturing the femoral artery, the doctor places a special catheter into the renal artery stenosis under the guidance of a high-definition X-ray machine, and then pushes out the stent compressed inside the catheter; once the stent is pushed out, it expands to the original design size and holds open the stenosis in a stable and uniform manner; after the blood vessel is opened, the blood circulation of the kidney can be effectively improved.
3.The main items of interventional treatment are currently being developed.
(1)Digestive system–interventional chemotherapy and embolization of medical malignant tumors in the liver, stomach, pancreas and intestines; dilation and stent treatment of benign and malignant stenosis and obstruction of esophagus and bile duct; interventional embolization treatment of hepatic hemangioma, liver cyst and hypersplenism.
(2) Respiratory system – interventional chemotherapy and embolization for lung cancer; interventional embolization for hemoptysis; dilation and stenting for benign and malignant airway stenosis and obstruction.
(3) Circulatory system – dilation and stenting for arterial and venous stenosis; thrombolytic therapy for acute and chronic peripheral arterial and venous thrombosis; embolization therapy for peripheral aneurysm and cavernous hemangioma.
(4) Neurological system – embolization of cerebrovascular disease (aneurysm, arteriovenous malformation, cavernous sinus fistula, etc.); thrombolysis of cerebral thrombosis in the acute stage.
(5) Bone and soft tissue system – interventional chemotherapy and embolization of malignant tumors of bone and soft tissue; vertebroplasty (for osteoporosis, vertebral collapse caused by metastatic tumors and vertebral hemangioma); interventional treatment of intervertebral disc herniation; interventional treatment of aseptic necrosis of the femoral head.
(6) genitourinary system – interventional chemotherapy and embolization of malignant tumors of kidney, pelvis and breast; embolization of uterine fibroids in the blood vessels;, interventional treatment of renal cysts, interventional treatment of pelvic hemorrhage.
Thus, with the continuous progress of clinical medicine and the development of modern science and technology, interventional therapy can undoubtedly bring a new dawn to mankind in conquering persistent diseases, and at the same time discover a broad prospect for the development of human life science.
4.Vascular interventional therapy for malignant tumors.
Vascular interventional treatment for malignant tumors includes tumor artery embolization and chemoembolization. Although selective arterial infusion chemotherapy is an important method for treating substantial malignant tumors, there are still characteristics such as rapid metabolism and excretion of infused drugs from the drug delivery organ and failure to significantly reduce the toxic side effects of normal tissue cells throughout the body. The tumor supply artery is temporarily or permanently blocked by vascular embolic agents, such as gelatin sponge, stainless steel ring and autologous blood clot, to reduce the size of the tumor and facilitate surgical resection and intraoperative bleeding.
For patients with inoperable advanced malignant tumors and arterial perfusion therapy, it can play a better palliative effect, relieve patients’ pain and bleeding symptoms, and prolong survival time. However, these embolization methods generally embolize larger arteries and branches, which can easily form collateral circulation to restore blood supply to tumor tissues within a short period of time, and the therapeutic effect is still unsatisfactory.
In recent 10 years, many scholars have researched on new drug formulations, i.e. drug carriers, which can combine anti-cancer drugs and embolic agents into target arteries to embolize the terminal branches of tumor tissues and block blood supply, and slowly release chemotherapeutic drugs to play the role of local chemotherapy, and significantly reduce the drug concentration in body circulation and systemic chemotherapy toxicity, which is called chemoembolization and has achieved obvious results. The effect is obvious.
The theoretical basis of chemoembolization is to combine the ischemic effect of tumor caused by embolization and the antitumor effect of chemotherapeutic drugs to achieve the purpose of killing tumor tissue. The main superiority of its synergistic effect is to increase the local drug concentration and prolong the local drug action time, while decreasing the systemic drug concentration and reducing the toxic side effects.
There are certain side effects and complications of malignant tumor chemoembolization: there are two major side effects and complications of malignant tumor chemoembolization: one is the complications caused by general interventional techniques and side effects of chemotherapeutic drugs; the other is the complications caused by embolization.
There are three main aspects as follows.
① Post-embolization syndrome: It can occur after most tumor embolization procedures, and the cause is usually thought to be organ ischemia, edema and tumor tissue necrosis. The main manifestations are nausea, vomiting, fever, pain and paralytic intestinal stasis. The fever usually does not exceed 38 degrees Celsius, but severe cases may have high fever, which can gradually return to normal within 1 week. Pain can occur at the time of bolus injection, and in severe cases, the bolus has to be discontinued. Treatment includes analgesia, antiemetic drugs, oxygen and other symptomatic treatment. To prevent infection, broad-spectrum antibiotics can be administered preoperatively and postoperatively.
② Misembolization and ectopic embolization: The catheter cannot be inserted super-selectively, the embolic agent is not selected properly, and the pressure of the injected contrast agent is too high, which can cause the embolic agent to reflux and misembolize other organs. Ectopic embolism can be caused by the collateral circulation between the target artery of embolization and other organs. Such as brain and lung infarction, ischemic necrosis of skin, gallbladder, intestine, nerves and limbs.
Prevention and management measures are
a. Perform detailed angiography before embolization to observe whether there are other normal organ collateral vessels or arteriovenous fistulas, and if there are, try to further super-selective cannulation to the target artery, or use larger proximal embolic agents to block collateral vessels or arteriovenous fistulas.
B. Select the appropriate embolic agent and embolization technique.
C. In case of misembolization or ectopic embolization, vasodilators, anticoagulants, hormones and other drugs should be given immediately to reduce the extent and degree of tissue infarction.
③Infection and abscess formation: It is less common, and the reason is mostly due to necrosis and liquefaction of tumor tissues after embolization, together with poor sterilization of surgical instruments, catheters and embolization agents or not strictly aseptic operation. The preventive measures are strict aseptic operation, autoclave treatment of embolization agent if necessary, preoperative and postoperative use of broad-spectrum antibiotics for prevention, etc. Once an abscess is formed, it should be treated by percutaneous puncture and drainage.