The arterial duct was originally a normal blood flow channel between the pulmonary artery and the aorta during fetal life. Since the lungs did not perform respiratory functions at that time, pulmonary artery blood from the right ventricle entered the descending aorta via the catheter, while blood from the left ventricle entered the ascending aorta. After birth, the lungs expand and assume the function of gas exchange, and the pulmonary circulation and the body circulation each perform their own functions, and soon the ducts close by choice due to disuse. If it does not close continuously, it constitutes a pathological condition called ductus arteriosus. Surgery should be performed to interrupt the blood flow. If the ductus arteriosus is coexisting with cyanotic heart disease with reduced pulmonary blood flow, the ductus is an important condition for survival and should be treated as such. Ductus arteriosus is a relatively common congenital cardiovascular malformation, accounting for 12-15% of all congenital heart disease. It is approximately twice as common in women as in men. In about 10% of cases, other cardiovascular malformations coexist. After the diagnosis of arteriovenous ductus arteriosus is established, if there are no contraindications (see below), surgery should be performed opportunistically to interrupt the blood flow at the ductus. In recent years, for premature infants with respiratory distress syndrome caused by unclosed ductus arteriosus, surgical treatment is also advocated, but less often the use of drugs to promote duct closure (prostaglandin synthase inhibitor – anti-inflammatory pain) treatment, because the latter is difficult to control the dose of drugs, the effect of a small amount is not obvious, a large amount of side effects, or duct reopening after discontinuation. In the last decade or so, a few medical marshals from Germany, Japan and other countries first used a combined intubation method via vein and artery, with a guide wire introduced from the femoral artery – Teflon sponge embolus, plugged into the arterial catheter to close it. Because of the limited use of arterial catheter lumen diameter, and every operation failure or lead to vascular collateral damage, so it has not been popularized. Arterial catheter closure surgery is usually performed before school age. If the fractional flow is large and the symptoms are severe, the procedure should be performed earlier. The risk of surgery increases with age and poor outcome after the onset of pulmonary hypertension. In cases of bacterial endarteritis, surgery should be postponed, but if the infection is not well controlled by medication, surgery should be sought. Surgery is contraindicated in cases of cyanotic cardiovascular malformations with reduced pulmonary blood flow, where the cyanotic lesion cannot be corrected at the same time. 2. Cyanosis of the toes at rest or after mild activity, or the presence of pestle toe. 3. 4. Body (femoral) artery oximetry with oxygen saturation less than 95% at rest or less than 90% after activity. 5. Ultrasound Doppler examination showing a reverse (right to left) shunt at the catheter or a bidirectional shunt predominantly right to left. 6. Right heart catheterization with a total pulmonary resistance of more than 10 Wood units. In cases where the pulmonary hypertension has reached a critical level, a catheter block test should be performed before the closed catheter operation during the operation. If there is no significant change in blood pressure and ECG during the 15-minute block period, the closed catheter operation should be completed again, otherwise the operation should be abandoned. Clinical manifestations] The clinical manifestations of arterial catheterization depend on the amount of blood flow from the aorta to the pulmonary artery and whether secondary pulmonary hypertension occurs and its degree. In mild cases, there may be no obvious symptoms, while in severe cases, heart failure may occur. Common symptoms include palpitations after exertion, shortness of breath, weakness, susceptibility to respiratory infections and dysplasia. Since the widespread use of antibiotics, bacterial endarteritis has become rare. In advanced pulmonary hypertension severe enough to produce a reverse shunt, lower body cyanosis is seen. On physical examination, the typical sign is a loud continuous machine-like murmur with tremor heard between the 2nd ribs at the left border of the sternum. The 2nd pulmonary artery sound is hyperactive, but often masked by the loud murmur. In large fractional flows, a diastolic murmur due to relative mitral stenosis can be heard in the apical region. Blood pressure measurements show that systolic pressure is mostly in the normal range, while diastolic pressure decreases, resulting in a widened pulse pressure and a watery pulse and gunshot sound in the vessels of the extremities. In infants and children, only a systolic murmur may be heard. In late pulmonary hypertension, the murmur is more variable and may be replaced by a systolic murmur only, or by a diastolic murmur with incomplete pulmonary valve closure (GrahamSteell murmur). In mild cases, there may be no significant abnormal changes in the electrocardiogram, but the typical manifestations are electrical axis deviation, left ventricular high voltage or left ventricular hypertrophy. In cases with significant pulmonary hypertension, both left and right ventricles are hypertrophied. In the advanced stage, right ventricular hypertrophy is predominant, and cardiac hypertrophy damage is present. Ultrasonography shows the ductus arteriosus and its communication with the aorta and pulmonary artery. Chest X-ray shows an enlarged heart shadow, with the left ventricle enlarging in the early stage and the right ventricle enlarging in the late stage, and the left atrium enlarging in those with more fractional flow. The ascending aorta and aortic arch are widened. The pulmonary artery segment is prominent. The pulmonary artery branches are thickened and the lung fields are congested. Sometimes the pulmonary hilar “dance”sign is visible under fluoroscopy. The mortality rate of surgery due to hemorrhage during arterial catheterization depends on the texture of the catheter wall, the surgical method used to close the catheter, and the skill of the surgeon, and should generally be within 1%. The rate of recanalization after catheter ligation or clamp closure is generally more than 1%, and the rate of recanalization after ligation with padding is lower than the first two. The long-term outcome of arterial catheter closure depends on the presence and extent of secondary pulmonary vascular disease before surgery. Patients who undergo surgery before pulmonary vascular disease occurs can recover completely and live as long as normal; those with severe irreversible pulmonary vascular disease will still have high pulmonary vascular resistance and heavy right heart load after surgery, and the results will be poor.