I. Transbronchial artery embolization of hemoptysis
Overview
Hemoptysis is a life-threatening emergency with a mortality rate of 50-100% with conventional conservative treatment. Until 40 years ago, surgical treatment was considered the only way to cure hemoptysis, and most patients were not candidates for surgery due to poor pulmonary reserve or concomitant disease, so the mortality rate still exceeds 40%. Bronchial artery embolization, as a minimally invasive approach, has become the treatment of choice for acute hemoptysis or recurrent hemoptysis.
Indications
Acute hemoptysis, where conservative medical treatment has failed and there is a possibility of airway obstruction.
Acute hemoptysis, palliative means before elective surgical procedures.
Recurrent hemoptysis.
Contraindications
Hypersensitivity to contrast agents and anesthetics.
Severe cardiac, hepatic, renal insufficiency and other serious systemic diseases.
Extreme debility and severe coagulation disorders.
Anatomical points
The main responsible vessels for hemoptysis are the bronchial arteries or the associated arteries of the body circulation; only about 5% of cases originate from the pulmonary arteries. The number, origin and course of bronchial arteries vary widely.
Generally, there are 1 to 2 left and 2 right bronchial arteries each, and in a few cases, there are 4 to 5 left and right arteries.
2, 60% to 70% of the bronchial arteries are located in the descending aorta from the upper edge of T5 to the lower edge of T6; 10% of the bronchial arteries originate from other levels of the descending aortic artery or the aortic arch; 20% of the bronchial arteries originate ectopically from the subclavian artery, cephalobrachial trunk, internal mammary artery, nail and neck trunk, subphrenic artery, abdominal aorta, etc.
3.According to the stroke distribution of bronchial arteries, they can be divided into left bronchial artery, right bronchial artery and common trunk bronchial artery. The most common one is the right bronchial artery intercostal trunk, which originates from the medial wall of the descending aorta at the level of T5 to T6 and is seen in 80% of patients; the left bronchial artery mostly originates from the anterior wall of the aorta; the common trunk bronchial artery is not uncommon and mostly originates from the anterior wall of the aorta at the level below the right bronchial artery intercostal trunk.
Preoperative preparation
1.Confirm the purpose of imaging and possible complications and accidents to the patient and family members, and sign the informed consent form.
2.Inquire about the medical history, study chest X-ray, CT, fiberoptic bronchoscopy and other examinations to understand the possible causes and sites of bleeding.
3.Establish intravenous access, check blood routine, heart, liver and kidney function and clotting time; detect patient’s vital signs, arterial partial pressure of oxygen and oxygen saturation; keep blood pressure stable and airway open; correct coagulation disorders, in principle, platelets should be above 7×109/L, international normalized ratio (INR, ≤1,5, partial thromboplastin time not more than 2 times of normal.
4.Iodine and anesthetic agents should be treated as necessary according to pharmacopoeia.
5.Four hours before surgery, no diet, 0, 5 hours before surgery, intramuscular injection of diazepam (Valium, 10mg.
Bronchial artery intubation and angiography
1.Cobra catheter is delivered to the level of descending aorta under fluoroscopy, or Simmons, Shepherd, Mikaelsson or Yashiro catheters can be used, and dexamethasone 5-10mg is applied via catheter or intravenous access.
2.The catheter head is slowly moved up and down in turn within each wall of the aorta at the level of the thoracic 5~6 vertebrae, i.e., one vertebra above and below the intersection of the left main bronchus and the aorta, and 1~75px3 contrast is pushed when the catheter head has a sense of embedding or hooking to determine whether it is a bronchial artery. The bronchial artery travels along the central trachea, which is different from that of the intercostal artery.
3. When the bronchial artery is confirmed to be a bronchial artery, the catheter tip is slightly rotated and moved up and down, and 5-10 ml of 45%~60% non-ionic contrast agent is injected at a rate of 1 ml~2 ml/second according to the fixation of the catheter tip, and digital silhouette angiography (DSA) is performed to understand the course and distribution of the bronchial artery, the presence of spinal artery branches and other lateral branch traffic. Signs suggestive of bleeding bronchial arteries include: 1) thickening (>3 mm, distortion, increased vascularity and parenchymal staining of the lung parenchyma; 2) bronchial aneurysm; 3) bronchial artery-pulmonary vein fistula; 4) bronchial artery-pulmonary artery fistula; 5) contrast extravasation.
Bronchial artery embolization
1, embolic agent selection: generally according to the size of the bronchial artery and pulmonary arteriovenous fistula, choose more than 300 microns of different diameter specifications of polyethylene-foam alcohol (PVA, particles, can also use gelatin sponge particles, but easy to recirculate to hemoptysis recurrence. For large bronchial artery-pulmonary vein fistulas, large gelatin sponge granules or strips can be used. For bronchial artery aneurysm, steel ring embolization can be used.
2. Fix the catheter tip and slowly push the granules mixed well in the contrast agent into the vessel under fluoroscopy to avoid reflux until the vessel is occluded and the contrast agent is retained. Advocate the use of microcatheters inserted into the more distal end of the vessel.
3. Review the contrast after the catheter is flushed with saline to observe the effect of embolization.
Points to note
1.If no bronchial artery can be found: 1.Expand the scope of search; 2.Change the catheter; 3.Whether there is a possibility of vagal bronchial artery, such as thoracic aorta, adjacent intercostal artery, internal mammary artery, subclavian artery, abdominal aorta, phrenic artery, renal artery, unnamed artery, thyrocervical trunk and other arteries of body circulation, and ascending aorta and descending aorta can be imaged if necessary.
2.After finding one responsible bronchial artery, the possibility of multiple responsible arteries should also be judged, and the search should be expanded according to the judgment of the bleeding site, such as other bronchial arteries, adjacent intercostal arteries, internal mammary artery, phrenic artery, etc.
3.When available, preoperative CT scan and enhancement of the chest should be performed, ranging from the lower neck to the upper abdomen, and CT angiography (CTA) should be performed to predetermine and localize all possible responsible vessels, which can significantly reduce the operation time and ensure the treatment effect.
4.The concentration of embolic agent should be moderate, and the injection should be slow to avoid embolization in the catheter, or proximal vessel embolization, or regurgitation.
5.If no obvious abnormality of bronchial artery or other vessels of body circulation is seen in the imaging, or if hemoptysis cannot be controlled after satisfactory embolization, the possibility of pulmonary artery lesion, such as pulmonary aneurysm or pulmonary arteriovenous fistula, should be considered, and steel ring or detachable balloon embolization can be used.
Complication prevention and management
1. Spinal cord injury Within a few hours after surgery, weakness or even paralysis of both lower limbs may occur, accompanied by sensory impairment and urinary retention. The main reason is that the intercostal artery, which is coterminous with the bronchial artery, can send out the root medullary artery, and the contrast agent or fine particles cause chemical or ischemic injury to the spinal cord. Prevention: 1. Hypotonic nonionic contrast should be used during contrast; 2. Carefully observe the presence of branches supplying the spinal cord on DSA images in typical hairpin rows, and use microcatheter superselection to avoid the presence of branches supplying the spinal cord and to avoid reflux. When the bronchial artery and intercostal artery are common, in principle, use the microcatheter to avoid the intercostal artery.3. The diameter of the embolic agent should not be too thin.4. The intubation should be done gently to avoid entrapment or thrombosis. Once the symptoms of spinal cord injury appear, they should be actively treated, including the use of vasodilators, such as poppy bases and salvia, to improve spinal cord blood circulation; the use of dexamethasone and mannitol to reduce spinal cord edema, etc.
2, body circulation misembolism In addition to proximal regurgitation, embolic agent can enter the body circulation through bronchial artery-pulmonary vein fistula and cause ectopic embolism, and in severe cases, it can cause intracranial embolism. The appropriate diameter of embolic agent should be selected according to the imaging.
3, tracheobronchial or esophageal necrosis Bronchial arteries supply not only bronchopulmonary but also trachea, esophagus, dirty pleura of diaphragm and mediastinum, vascular trophoblast of aorta and pulmonary artery, myocardium, etc. Too fine embolic particles can cause tissue necrosis.
4, interventional complications such as temporary arterial spasm, puncture site hematoma or pseudoaneurysm or arteriovenous fistula formation, catheter intra-arterial fracture, intimal entrapment, atherosclerotic plaque detachment, vascular rupture, thrombosis and air embolism, and contrast allergy or contrast-induced nephropathy, etc. should be avoided by strict and careful operation according to the standard.
Efficacy evaluation
The literature reports that immediate hemostasis is achieved in 73-99% of patients after bronchial artery embolization, while the recurrence rate is generally in the range of 10-55,3%. Re-bleeding in the first week or month after surgery is usually due to incomplete embolization of the responsible vessel or the progression of the underlying disease. In contrast, the late recurrence rate may be due to the progression of the primary disease. For early recurrence, bronchial artery embolization can still be performed again and the responsible vessel that was not completely embolized can be searched for. The autopsy results of a group of 1114 patients with chronic tuberculosis revealed the presence of pulmonary aneurysms in 45 cases (4%, of which 38 patients died due to aneurysm rupture, so the possibility of pulmonary artery hemorrhage should be considered in patients with very complete embolization of the responsible vessel of the body circulation.