Section 1 Overview
Gastrointestinal bleeding is one of the common clinical symptoms of gastrointestinal lesions, and angiography is very effective in the diagnosis and treatment of gastrointestinal bleeding. The GI tract is divided into the upper and lower GI tracts by the duodenal suspensory ligament (Treitz ligament). For the diagnosis of GI bleeding, most of them can be clearly diagnosed through clinical history analysis, laboratory tests, imaging and instrumentation. However, there are still some patients who cannot find the cause of bleeding and the site of bleeding despite various examinations, and effective treatment cannot be performed. For these patients, selective abdominal arteriography is necessary. Selective angiography can not only show the direct signs of contrast extravasation, but also reveal the lesions, including the hidden lesions with abundant blood vessels, and finally choose the best plan of surgical, medical or interventional treatment to control the disease after comprehensive analysis. Transcatheter infusion of vasoconstrictive drugs or embolization treatment methods are safe and simple, with rapid and reliable efficacy, often achieving immediate results.
Section 2: Diagnosis of Gastrointestinal Bleeding
Etiology
Common causes of GI bleeding include gastric ulcer, duodenal ulcer, hemorrhagic gastritis or other inflammatory diseases, neoplastic lesions, diverticula, polyps, postoperative gastrointestinal surgery, anastomotic ulcers and tumors, variceal bleeding due to portal hypertension, poor coagulation mechanisms, abnormal vascular development such as arteriovenous malformations, colonic vasodilatation, etc.; medically induced bleeding mainly includes endoscopic polypectomy biopsy and endoscopic biliary sphincterotomy, biliary bleeding after liver or biliary tract surgery, biopsy and interventional operations on the liver.
Clinical manifestations
Clinical manifestations are related to the site of bleeding and the amount of bleeding per unit time. It can manifest as occult blood in the stool, chronic bleeding or acute hemorrhage. In addition to vomiting blood and black stool when the bleeding volume is large, the patient may have dizziness, cold sweat, decreased blood pressure, increased heart rate, and fine and rapid pulse.
Diagnosis by imaging
(A) Barium examination of the digestive tract
This is a routine examination method, which mainly shows the morphology of the lumen of the digestive tract and the surface of the mucosal folds, but barium contrast examination is often negative for submucosal lesions and vascular lesions in the intestinal wall. Usually barium gastrointestinal examination is not recommended in patients with acute GI bleeding. Upper gastrointestinal endoscopy and colonoscopy can detect part of the cause of bleeding and clarify the site of bleeding, and the corresponding treatment is often feasible.
(B) Isotope venous scan
Isotope venous scan can detect gastrointestinal bleeding of 0.1 ml/min, and its sensitivity is 45% to 90%, which can roughly understand the site of bleeding, but accurate localization is still difficult. The sensitivity and accuracy of this method can be significantly improved by injecting isotope into the target artery via catheter.
(iii) Selective arteriography
When the rate of GI bleeding is 0.5 ml per minute or more, selective arteriography can show the abnormal vessels in the GI tract and determine the site of bleeding according to the source of its blood supply artery, which is an important method for diagnosing GI bleeding. Factors affecting the positive diagnostic rate include: (1) the nature of the lesion; (2) the amount and speed of bleeding; (3) the timing of angiography; (4) the technique and equipment of angiography, etc.
I. Angiography and interventional treatment of GI bleeding
Preoperative preparation
(A) Patient preparation
1. Preoperative family conversation and signature of informed consent for surgery.
2.Preparation of perineum skin.
3.Iodine allergy test.
4.Blood routine, prothrombin time, partial thromboplastin time.
5.Assess liver and kidney function and coagulation status, if abnormal coagulation mechanism is found, it should be corrected first.
6.Leave the venous access.
7.Patients with excessive blood loss should be given blood transfusion and blood volume supplementation before operation.
8.The corresponding clinical management of the primary disease and other lesions causing hemorrhage.
(B) Instrument preparation
1.Puncture needle, guidewire, catheter sheath and catheter required for angiography.
2. 4F Cobra catheter or long loop catheter and super-slip guidewire are often used for super-selective cannulation.
(C) Drug preparation
Heparin, contrast agent, local anesthetics, routine resuscitation drugs, etc.
II. Contrast examination
(I) Seldinger puncture technique
The femoral artery puncture site is chosen 1 to 3 cm below the midpoint of the groin where the arterial pulsation is most obvious. For those with little subcutaneous fat, the puncture point should be lower; for those who have been punctured and cannulated several times, the puncture point can be higher, but the arterial puncture internal port should not be higher than the inguinal ligament. Points to note: ①When using the catheter sheath, it is advisable to exchange the catheter through the guidewire for those who are older or estimated to have significant distortion of the iliac artery to prevent entering the iliac artery entrapment when entering the catheter; ②If the guidewire enters the external iliac artery or deep femoral artery, the guidewire can be carefully backed into the femoral artery or the puncture needle under fluoroscopy, and the guidewire can be rotated or the angle of the puncture needle can be changed before entering the guidewire; ③In those with thick subcutaneous fat, after successful puncture, the guidewire should be pressed into the iliac (3) In case of thick subcutaneous fat, after successful puncture, the hand pressing on the artery should remain in place until the guidewire enters the iliac artery to avoid changing the depth of the needle.
(ii) Angiography
In the past, the timing of angiography has been chosen to show signs of bleeding during the active bleeding period. As early as 1963, Baum and Nusbaum et al. performed animal experiments in dogs with tubes of different diameters placed in small segmental arteries through anastomosis and detected bleeding of 0.5 ml per minute with cineangiography. According to the literature, in clinical practice angiography shows a bleeding rate of approximately 1.0-1.5 ml per minute or more of contrast spillage. For acute gastrointestinal bleeding, angiography or emergency angiography during active bleeding is advocated; for recurrent bleeding, there is no need to emphasize performing it during active bleeding to avoid delaying the disease, because angiography showing the lesion is more important than showing signs of contrast spillage. In cases with negative intermittent contrast, pharmacological angiography with vasodilators or waiting for repeat angiography during active bleeding is advocated. Therefore, mesenteric artery and/or celiac artery angiography should be performed as early as possible under appropriate conditions and timing, and selective or superselective angiography should be performed when a bleeding lesion or suspected bleeding lesion is found.
(iii) Diagnostic angiography
Signs of angiography for the diagnosis of gastrointestinal bleeding include: (1) signs of contrast spillage; (2) abnormal vessels of the lesion. Swelling
Tumor lesions can show abnormal vessels and vessel displacement of the tumor, and tumor vessel staining can be seen. Poor vascular structure shows abnormalities such as thick and thin vascular plexus, irregular dilatation and tortuosity of terminal vessels, and early manifestation of draining veins. Angioma shows abundant blood sinus and abnormal thickening of blood supplying arteries.
Interventional treatment
(A) Indications and contraindications
1. Indications
The indications for interventional therapy are refractory gastrointestinal bleeding due to various causes and those with clear direct signs of gastrointestinal bleeding found by angiography. These include traumatic bleeding, medical bleeding, primary or secondary tumor bleeding, inflammatory bleeding, portal hypertension, aneurysm, vascular malformation and other refractory bleeding.
Unexplained gastrointestinal bleeding, and the cause of bleeding still cannot be clarified by endoscopy
Gastrointestinal bleeding of various causes, ineffective through conservative medical treatment
Acute gastrointestinal hemorrhage and clinically unavailable for surgical operation
Medically induced bleeding: biliary bleeding due to liver injury caused by surgery, interventional operation, percutaneous liver puncture, etc.
2.Contraindication
There is no absolute contraindication. However, cases of serious organ insufficiency (heart, liver, kidney), patients with bleeding and coagulation disorders, and patients with serious infections should be relative contraindications, and intervention should be done with caution. Recent myocardial infarction, severe coronary artery disease, and poor myocardial reserve should be considered as contraindications to vasopressin. Iodine allergy.
(II) Operation technique
After the cause and site of bleeding are identified by selective angiography, drug perfusion therapy or embolization therapy is selected to control gastrointestinal bleeding according to the condition. Generally, for diffuse capillary hemorrhage such as hemorrhagic gastritis, Mallory-Weiss syndrome, portal hypertension esophageal varices, and inflammation, vasoconstrictor perfusion can be used to stop the hemorrhage; whereas for lesions such as tumorigenic lesions, ulcers, vascular dysplasia, and other lesioned vessels that do not respond well to vasoconstrictors, as well as arterial hemorrhage, vascular embolization therapy can be chosen when possible.
The options for transcatheter treatment are embolization therapy and vasopressin perfusion therapy. The embolic materials required for embolization therapy are classified as absorbable embolic agents (e.g., gelatin sponges) as well as non-absorbable embolic agents (stainless steel spring coils, silk, balloons, polyethylene alcohol, etc.). The advantages of vasopressin infusion therapy are that it does not require super-selective intubation, and if the treatment fails, embolization therapy can be chosen again, the disadvantage of which is that close ICU monitoring is required, and cardiovascular complications may further lead to hypovolemic shock, etc.; the advantages of embolization therapy are rapid hemostasis, no indwelling catheter, no cardiovascular side effects, etc., the disadvantage of which is that the success rate of treatment and complications are closely related to the technical level of the operator The disadvantage of embolization is that the success rate and complications are closely related to the skill level of the operator, and it is easy to cause ischemia and necrosis in the digestive tract.
1. Perfusion therapy
After the site of bleeding is clearly identified, generally no super-selective cannulation is required (additional super-selective cannulation and imaging is required for suspicious sites), and the vasopressin is started to be perfused at a rate of 0.2 U/min with a microinjection pump, and the pressin is diluted with isotonic sodium chloride injection. 20 min~30 min later, angiography is performed for review, and if the spillage of contrast agent is still seen, the dose is increased to 0.4 U/min. If the bleeding has stopped, maintain the infusion with the original dose for 12h～16h, then reduce the drug to 0.1U/min. After 24h, if the angiography and clinical evidence show that the bleeding has been controlled, stop the drug infusion and keep the tube for observation for 12h～16h. The tube can be removed when the bleeding has clinically stopped. If the bleeding is again, repeat the perfusion treatment or embolization treatment.
If the bleeding does not stop, discontinue the use of pressin and switch to other therapies such as surgery. Surgical treatment can be done by inserting a catheter into the blood vessel of the lesion, and then placing a short guidewire to show the bleeding site, so as to provide convenience for surgery and make it easy for surgeons to find the diseased intestinal segment quickly during the surgery.
2.Embolytic treatment
It is generally believed that for organs with more collateral circulation, such as stomach, duodenum, liver and other bleeding, arterial embolization therapy is feasible. For small intestine or colon bleeding, because its collateral circulation is not abundant, especially below the arch anastomosis is the terminal vessel, because embolization is easy to cause intestinal necrosis. Later experimental and clinical studies have shown that super-selective embolization with gelatin sponge particles before the arch anastomosis has a better hemostatic effect and generally does not lead to intestinal necrosis. However, embolization therapy still needs to be used with caution, especially after treatment with vasoconstrictor perfusion first and then embolization therapy is extremely risky and should be considered contraindicated. The choice of embolization agent, lesion site and embolization modality can be considered as follows.
(1) Mallory-Weiss syndrome and diffuse gastric bleeding, gelatin powder can be used for embolization via the left gastric artery or superior gastroduodenal artery.
(2) Gastric ulcer, gastric cancer, and duodenal bleeding, generally using gelatin sponge pellets for embolization via the superior gastroduodenal artery.
(3) Gastrointestinal aneurysm and surgical or traumatic arterial bleeding, including biliary bleeding, can be embolized with stainless steel spring ring and gelatin sponge strips.
(4) Small intestine or colon artery bleeding or tumor bleeding can be treated with embolization first without surgery. Super-selective cannulation is required to the main trunk of the bleeding artery, such as ileocolic artery, jejunal artery, etc. The embolization agent can be 2mm2mm2mm size gelatin sponge particles. Inject 5 to 10 pellets each time, and then contrast review. Contrast agent spillage or pathological vessels can be stopped without visualization, and excessive embolization should be avoided. The level of embolization should be above the anastomotic branch of the intestinal artery arch is preferred.
(5) Granular embolization of the splenic and gastric left arteries or stainless steel spring coil embolization can be used for portal hypertensive venous bleeding. Hemostasis is achieved mainly by indirectly lowering portal venous pressure.
(6) Percutaneous coronary variceal embolization of the stomach is mainly used for hemostasis of acute esophageal and fundic venous hemorrhage due to portal hypertension, similar to surgical flow dissection, which is more complete because the embolic agent is distributed with the blood flow. The right branch of the portal vein is punctured using PTCD through the right axillary midline approach, and a Cobra catheter is successfully delivered and super-selectively inserted into the coronary vein of the stomach opening from the confluence of the splenic or splenic portal veins to show the degree of varices and the direction of blood flow, etc. When the varices are mild, 5 ml to 8 ml of anhydrous alcohol or sodium cod liver oil acid alone can be injected within 2 to 3 seconds. A short pause of a few minutes is used to re-investigate the degree of slowing of blood flow. If necessary, add a small amount of embolic agent until the blood flow stops. For those with thick blood vessels and fast flow rate, gelatin sponge strips or granules can be injected together with the above embolic agent, and finally stainless steel spring ring is added to consolidate the embolic effect.
3.Postoperative treatment
Routinely observe whether there is bleeding or hematoma at the puncture site, and restrict the activity of the lower limb to prevent the formation of hematoma at the puncture site. Observe the arterial pulsation of the lower limb to prevent thrombosis. Observe for cardiac arrhythmia or coronary ischemia. Observe whether there are signs of continued bleeding.
4.Efficacy evaluation
If gastrointestinal bleeding is treated by catheterized drug infusion therapy or embolization, 80% to 90% of patients can control bleeding, but 15% to 30% have recurrence and still need surgical treatment. For older patients or patients with other serious diseases, the surgical mortality rate is high, and repeated instillation or embolization treatment can be considered to control bleeding.
IV. Complications and their management
Possible complications of general angiography include: large hematoma, arterial embolism, thrombosis or embolism and pseudoaneurysm. Relevant symptomatic management may be performed.
Possible complications of GI bleeding interventions are usually varying degrees of abdominal pain due to local ischemia and necrosis of gastrointestinal tract tissues caused by vasopressin, and embolization of non-target organ arteries. If the abdominal pain is persistent for more than 20 min and progressively worsens, the possibility of intestinal ischemia should be considered. Intestinal ischemia can be caused by excessive dose, improper catheter placement, entry into small branches of blood vessels, or thrombosis. It is necessary to immediately review the imaging, take a small dose or stop the perfusion, adjust the catheter position and other appropriate treatment.
Systemic side effects caused by vasopressin commonly include antidiuretic hormone reactions and cardiac reactions, which manifest as water retention, electrolyte disturbances, elevated blood pressure, arrhythmias, angina pectoris, and myocardial infarction. Therefore, patients with indwelling catheters for drug perfusion should have cardiac monitoring and urine volume calculation in the monitoring room. If systemic reactions to vasopressin are found, the perfusion dose should be adjusted or stopped immediately, and symptomatic treatment should be provided.
In addition to splenic flexure and rectum, there is only one blood supply artery in small intestine and colon, and the lateral branch anastomosis is not abundant, so embolization often causes ischemia and even intestinal necrosis. Therefore, embolization of the mesentery should be done with caution to prevent excessive embolization of the vessels below the arch anastomotic branch and super-selective intubation as much as possible.
To avoid complications, in addition to choosing the appropriate embolic agent, the position of the catheter, injection speed and pressure should be carefully observed under TV fluoroscopy during the operation, and superselective cannulation should be done as much as possible to prevent embolic agent reflux and reduce the range of embolized vessels.