Coarctation segment resection and end-to-end aortic anastomosis

Congenital aortic coarctation is a more common congenital vascular malformation, accounting for 7% to 14% of congenital heart disease. The narrowing is mostly located in the aortic isthmus, the distal part of the left subclavian artery, and can usually be divided into a pre-catheter type and a post-catheter type. The former is also known as the infant type, the constriction is located at the proximal end of the arterial catheter, and the distal end of the left subclavian artery is often accompanied by patent ductus arteriosus. The latter is also known as the adult type. The constriction is located at the distal end of the arterial catheter or arterial ligament and distal to the left subclavian artery. In most cases, the arterial catheter is closed. A small number of patients can be narrowed in the thoracic aorta or descending aorta diaphragm plane or below the renal artery. The narrowing range is usually limited, and it can also narrow the length. The degree of narrowing is different, the inner diameter can be 2 to 5 mm, and it can be narrowed to only pass through the probe. The difference between the disease and the aortic arch interruption is that the aortic coarctation has a narrow lumen in the narrowed part, but still keeps the lumen unobstructed. Curing disease: Indication 1. The appropriate surgical age for children with simple aortic coarctation is 4 to 8 years old. Because the cross-sectional area of the aortic lumen of 4-8 years old children has exceeded 50% of adults, there is less chance of re-narrowing after surgery. In the case of over-age surgery, postoperative residual high blood pressure may affect the efficacy. 2, infants and young children with severe symptoms of dyspnea, refractory heart failure, patients with active medical treatment should be treated immediately. 3, narrowing lesions are more limited, no more than 2.5cm. 4, the principle of treatment of intracardiac and external deformities: (1) Neonatal combined with large ventricular septal defect, the aortic coarctation should be relieved at the same time as pulmonary artery contraction to reduce pulmonary blood flow, delay the occurrence of pulmonary vascular obstructive disease, and repair the ventricular septal defect in the second phase. (2) Infants with more than one month can repair ventricular septal defect and relieve aortic coarctation at the same time. (3) Surgical correction should be performed concurrently with aortic stenosis or patent ductus arteriosus. Contraindications 1. The long section of the aorta is narrowed. 2, severe aortic dysplasia accompanied by diffuse sclerosis or calcification. 3. Severe myocardial damage. Preoperative preparation 1, sick children with congestive heart failure, should be treated with oxygen and cardiac diuretic, control heart failure. 2, severe heart failure with acidosis and systemic hypoperfusion of the sick children should be mechanically assisted breathing, input sodium bicarbonate to correct acidosis. Prostaglandin E can be applied at a dose of 0, 1 g / (kg · min). To expand the patent ductus arteriosus to expand systemic perfusion. Patients with renal failure should undergo dialysis before surgery to correct electrolyte imbalance. 3, the choice of basic methods When aortic constriction is performed surgically, it is often necessary to block the descending aorta of the upper and lower ends of the constricted segment. In order to protect the spinal cord and distal organs from ischemic damage during the blockage of the descending aorta, low temperature, temporary vascular bridge and left heart bypass are also used. (1) After low temperature general anesthesia, the body surface is cooled to about 32 °C. The application indications were: 1 adult patient; 2 collateral circulation dysplasia; 3 aortic or intercostal artery formation near the narrowing segment; 4 re-narrowing the second operation. Dubost used superficial hypothermia in 900 patients with aortic coarctation, and only 1 patient developed transient spinal cord injury after surgery. (2) Temporary vascular bridge in the upper and lower end of the constricted section descends the aortic frame and retracts the narrow section of the temporary vascular bridge to communicate and block the blood circulation of the upper and lower end of the descending aorta. After the operation, the blood vessel is removed, and the method is simple, and the spinal cord and the abdominal organs can be effectively protected during the operation. DeBakey is used to narrow down the second surgery and difficult cases. No spinal cord damage occurred. (3) The advantage of this method is that it is easy to operate, can protect the spinal cord and abdominal organs, and can adjust the flow according to the blood pressure of the upper limb at any time, so as to avoid cerebrovascular accident due to high blood pressure in the upper body. The application indications are: 1 the length of the narrowed segment is long; 2 the collateral circulation is poorly developed, the distal pressure drops below 50 mmHg after the descending of the descending aorta; 3 the intercostal artery must be ligated; 4 the descending aorta After the blockage, the proximal pressure rose to above 200 mmHg; the descending aorta near the narrowed section showed a tumor-like dilation. Surgical procedure 1. The left intercostal space of the fourth intercostal space was inserted into the chest. The mediastinal pleura was cut along the descending aorta and extended to the left subclavian artery and the upper intercostal artery, down to the constricted plane 4 cm. The aorta is descended at the upper and lower ends of the narrowed segment. And separately wrapped, in case of inadvertent damage to blood vessels, control bleeding. 2, free ligation and cut off the patent ductus arteriosus or arterial ligament, free catheter should pay attention to avoid damage to the recurrent laryngeal nerve. When the suture is to be cut, two catheter clamps should be placed at both ends of the catheter. After cutting, suture with a 5-0 polypropylene thread. The arterial ligament should also be ligated and cut. 3, free and ligation of intercostal artery, intercostal artery is the most important collateral circulation. The intercostal arteries are often thickened, the walls are fragile, and even tumor-like expansion. In order to fully expose the aortic constriction, if necessary, ligation or 1 or 2 pairs of intercostal arteries may be ligated. In the case of free intercostal arteries, it should be slightly away from the wall of the aorta. When it is free, it should be handled gently to prevent rupture of the blood vessels or tearing of the aortic wall, resulting in uncontrolled bleeding. The free intercostal artery should be of sufficient length to be severed after double ligation. If the intercostal artery is tumor-like dilatation, the aortic constriction may be exposed first, and the non-invasive vascular clamp may be placed on the upper and lower ends of the narrowed section, and the narrowed section is cut off, and the distal descending aorta is turned over, which is good. The intercostal artery is exposed and ligated and cut. 4, narrowing segment resection and end-to-end anastomosis in the constricted segment of the descending aorta proximal and distal to each place a non-invasive vascular clamp, resection of the narrowing section, anastomosis, the upper and lower end of the vascular clamp gently close together, To reduce the tension of the vessel wall anastomosis and ligation. Apply 4-0 polypropylene suture line breaks or continuous eversion plus intermittent suture to align the intima. When suturing and ligating the last needle, care should be taken to drain the gas in the lumen of the blood vessel. complication 1. Bleeding: often due to thickening of the intercostal artery or expansion of the tumor, causing the suture to fall off or severing the vessel wall after ligation, or due to the degeneration of the vessel wall, causing the suture to be separated in the anastomotic site, and should be immediately opened for exploration. Stop bleeding. 2, the incidence of abnormal hypertension after surgery is 5% to 10%. The postoperative upper and lower extremities blood pressure was higher than that before surgery, while the aortic blood flow was not obstructed, and the cause was unknown. More common in patients with collateral circulation dysplasia, or older patients at the time of surgery. In severe cases, blood pressure can rise to 180 ~ 200mmHg. Vasodilators should be given blood pressure to relieve heart and brain load and avoid cerebrovascular accidents. 3, the narrowing of its incidence has been reported in different literatures, the incidence of re-narrowing of the incision end-end anastomosis in infants and young children is significantly higher than that of the left subclavian artery flap angioplasty. The reasons for further narrowing are: 1 insufficient resection of the narrowing section; 2 anastomotic failure does not increase with the growth and development of infants and young children, especially the use of continuous suture to limit the growth of the anastomosis; 3 residual duct tissue, the duct tissue contains muscle fibers And extended to the aortic wall, when it is fibrotic, can cause re-narrowing; 4 anastomotic embolization should be corrected again. 4. The incidence of ischemic spinal cord injury was 0,41%. Causes and no effective protective measures were taken during the operation; collateral circulation was poorly developed; spinal cord vascular variability and ligation were related to intercostal arteries. Spinal ischemic damage manifests as mild paralysis of the lower extremities, complete paraplegia, Brown-Sequard damage, and the like. 5, abdominal pain patients may have abdominal discomfort after a few days can gradually recover. A small amount of abdominal pain is obviously accompanied by abdominal distension and weakened bowel movements. It should be fasted, rehydration and gastrointestinal decompression. In severe cases, intestinal necrosis or intra-abdominal hemorrhage due to mesenteric arteritis should be explored by laparotomy.

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