How to treat patent ductus arteriosus

What methods are used to treat patent ductus arteriosus? As parents, we will be very worried when our children have some problems. If the child has patent ductus arteriosus, we will be even more frightened. We all want to cure the child's disease as soon as possible. So, what methods are used to treat patent ductus arteriosus?

Patent ductus arteriosus in premature infants can close naturally after birth when they reach mature age, so asymptomatic infants can be left untreated. If there are symptoms, prostaglandin synthetase inhibitor indomethacin can be used for treatment, 0.2 mg/kg each time. If it is ineffective, it can be repeated 1 to 2 times every 8 hours, and the total amount should not exceed 0.6 mg/kg. It is contraindicated for patients with poor renal function, serum creatinine>132.6umol/l (1.5 mg/dl), or urea nitrogen>7.1mmol/l (20 mg/dl), bleeding tendency, platelets<50×109/l, or suspected necrotizing enterocolitis. Or aspirin 20 mg/kg every 6 hours, a total of four treatments, the ductus arteriosus may be closed within 24 to 30 hours. For those who are ineffective with indomethacin or have contraindications, surgical treatment should be given in a timely manner.

1. Indications for surgery

Under current conditions, the risk of surgical treatment of this disease is very small, and the surgical mortality rate is close to 0.5~1.0%. Except for some children with patent ductus arteriosus with a diameter of 0.3~0.8cm, who can undergo interventional treatment, most patients should undergo surgical treatment once diagnosed. Symptomatic patients should undergo early surgery. Patients with thin ductus arteriosus, asymptomatic patients, and those who do not affect their development should undergo surgery before school age (2~5 years old). Patients with pulmonary hypertension should undergo surgery as soon as possible. Premature infants and infants with repeated pneumonia, respiratory distress and heart failure, which are difficult to control with drugs, should consider surgical treatment in time. Patients with bacterial endocarditis generally need to be treated with antibiotics first, and then undergo surgical treatment after the infection is controlled for 4~8 weeks. For a few patients whose infection cannot be controlled by drug treatment, especially when there is shedding of vegetation, repeated arterial embolism, or formation of pseudoaneurysm, surgical treatment should be given in time.

2. Contraindications to surgery

1. Patients with severe pulmonary hypertension, with right-to-left shunt as the main symptom, and clinical differential cyanosis, the arterial catheter has become the right heart blood discharge channel, and surgery is contraindicated.

2. In complex congenital heart diseases, patent ductus arteriosus exists as a compensatory channel, such as pulmonary atresia, tetralogy of Fallot, interrupted aortic arch, transposition of great arteries, etc. At this time, patent ductus arteriosus is the only or important way for low-oxygen saturated blood to enter the lungs for oxygenation. Before radical surgery for complex congenital heart disease, ductus closure surgery alone cannot be performed.

(III) Preoperative preparation:

1. Comprehensively and carefully inquire about the medical history and conduct relevant examinations to determine whether there are any combined deformities and complications, and determine the surgical plan based on the results.

2. Patients with severe pulmonary hypertension or even a small amount of right-to-left shunt should be given oxygen therapy (min each time, twice a day) and vasodilators (such as prostaglandin E, sodium nitroprusside, phentolamine, etc.) before surgery, which will help reduce the resistance of the entire lung and create conditions for surgical treatment.

3. For patients with concurrent heart failure, active cardiotonic and diuretic treatment should be given, and surgery should be performed only after the heart failure is under control.

4. For patients with lung and respiratory tract infections, timely anti-infection treatment should be given and surgery should be performed after the infection is cured.

5. Patients with bacterial endocarditis should undergo blood bacterial culture and drug sensitivity test before surgery, and strengthen anti-infection treatment. Surgery should be performed after the infection is controlled. Patients with uncontrolled infection or recurrent embolism should undergo elective surgery while taking anti-infection.

4. Preoperative communication:

Before the operation, the patient and his family must be explained the necessity of the operation and the possible risks and complications such as massive bleeding, hoarseness, catheter recanalization, lung perfusion, etc. The operation can only be performed if the patient and his family fully understand and agree.

(V) Surgical method:

Currently, the commonly used surgical methods are divided into left chest lateral incision ligation, left chest lateral incision cutting and suturing, left chest lateral incision clamping, median sternotomy incision arterial duct ligation, and pulmonary artery duct closure under extracorporeal circulation. Among them, left chest lateral incision ligation and pulmonary artery duct closure under extracorporeal circulation are the most commonly used. In recent years, there are also interventional methods that use cardiac catheterization to send sponge-like plastic plugs, umbrella-shaped, button-shaped or spring-shaped patches to the patent arterial duct to occlude it, eliminating the need for open-chest surgery, but this operation cannot completely replace open-chest surgery.

1. Left thoracotomy ligation

(1) Anesthesia and body position

Endotracheal intubation and intravenous combined anesthesia.

The patient lies on the right side at 90°, with the left arm placed in front and the right armpit elevated to widen the intercostal space on the surgical side, facilitating exposure of the surgical field.

(2) Incision

The left posterior lateral chest incision should be made from 1 horizontal finger below the lower angle of the scapula to avoid rubbing the surgical incision during postoperative scapular movement, causing pain. Enter the chest through the fourth intercostal space or remove the fourth rib to obtain good exposure of the aortic isthmus arterial duct and the hilum of the lung.

(3) Exploring the ductus arteriosus: After opening the chest, pull the left lung forward and downward. The bulge seen in the ductus arteriosus triangle formed by the pulmonary artery, vagus nerve, and phrenic nerve is the location of the ductus arteriosus. Use your fingers to touch this triangle and you can feel a continuous tremor. After pressing the ductus arteriosus triangle, the tremor of the pulmonary artery trunk disappears or is alleviated.

(4) Open the mediastinal pleura: Open the mediastinal pleura along the longitudinal axis of the descending aorta, from the left subclavian artery to the hilum of the lung. The uppermost intercostal vein can be ligated and cut. When separating the left subclavian artery, care should be taken not to injure the lymphatic vessels. Any suspected lymphatic vessels should be ligated to avoid postoperative lymphatic leakage.

(5) Expose the arterial duct: Separate the cut mediastinal pleura toward the pulmonary artery side to the pulmonary artery end of the arterial duct. Use No. 4 silk thread to sew 3 to 4 traction stitches on the edge of the mediastinal pleura, pull and fix it on the sterile towel. At this time, the arterial duct, aortic arch, left subclavian artery, pulmonary artery, vagus nerve and recurrent laryngeal nerve are all clearly visible.

(6) Separation of the catheter: Generally, the front wall of the catheter is separated sharply with stripping scissors first. Then the lower edge is separated, and the ligament tissue above the catheter is carefully cut to expose the upper edge of the catheter. Then, the catheter is separated upward along the upper edge of the catheter. Finally, a small right-angle pliers is used from bottom to top, extending the upper edge of the catheter along the back wall of the catheter. Then, the right-angle pliers are used from the top to gently expand the gap of the back wall of the catheter appropriately, and the surrounding areas of the catheter are completely freed.

(7) Blocking test: Use small right-angle forceps to guide two No. 10 silk threads, gently bypass the posterior wall of the arterial catheter, temporarily block the catheter, and observe the heart rate and blood pressure. If blood pressure drops and tachycardia occurs, close the catheter with caution. Do not tie the thread too fast when passing through the posterior wall of the catheter to avoid damaging the posterior wall tissue of the catheter.

(8) Ligating the catheter: Ask the anesthesiologist to lower the blood pressure to 70-80 mmHg systolic, first ligate the aortic end of the arterial catheter, and at the same time touch the pulmonary artery side with your fingers. If the tremor does not completely disappear, it means that the ligature is not tight, and the ligature must be tightened until the tremor disappears. Then ligate the pulmonary artery end. Each ligature should be separated as much as possible to avoid overlapping. When ligating, apply force evenly and slowly to prevent excessive force from damaging the catheter wall and endothelium.

(9) Suture the incision: Suture the mediastinal pleura, stop bleeding thoroughly, check the instruments and gauze to make sure they are correct, place a closed chest drainage tube in the sixth intercostal space at the left midaxillary line, and ask the anesthesiologist to inflate the lungs and close the chest.

This procedure is the most commonly used and is suitable for children with long ducts and low pulmonary artery pressure.

2. Left chest incision cutting and suturing

The surgical incision and exposure are the same as those for patent ductus arteriosus ligation. After the catheter is fully freed and the pressure is reduced, use two catheter clamps or Pott-Smith clamps to clamp the main and pulmonary artery ends of the catheter in parallel. The distance between the two clamps should be no less than 3~4mm to facilitate cutting and suturing. Use 4-0 or 5-0 prolene thread to cut and suture the aorta side between the two clamps. Generally, the first layer is an intermittent mattress suture and the second layer is a continuous suture. Then suture the pulmonary artery cut edge. After suturing, first open the Pott-Smith clamp at the pulmonary artery end. If the needle eye bleeds, use hot gauze to compress and stop bleeding. If there is still bleeding, add mattress sutures, and then open the Pott-Smith clamp at the aorta end.

This procedure is suitable for cases where the catheter is too large, or where there is intraoperative injury and bleeding or infection and ligation is not suitable.

3. Left thoracotomy with clamping

Use a clamp to insert a metal tantalum nail of appropriate size to close the catheter. After the catheter is freed, wrap a thick wire around it as a guide for placing the clamp. The clamp is inserted through the gap between the aortic and pulmonary artery grooves, first clamping the aortic end and then the pulmonary artery end. Be careful to push the recurrent laryngeal nerve away to prevent it from being embedded in the clamp and causing damage.

This procedure is simple to operate and has a definite effect.

4. Ligation of patent ductus arteriosus through median sternotomy

A median sternotomy was performed, and the pericardium was cut longitudinally to open the sternum. After the extracorporeal circulation cannula was intubated, the assistant pulled down the pulmonary artery trunk under auxiliary circulation to expose the pericardial fold at the distal end, cut the parietal pericardium longitudinally, and searched for and carefully separated the arterial duct above the bifurcation of the pulmonary artery. The aortic side was separated first, and then the left pulmonary artery side. Then, a right-angle clamp was used from the upper edge of the left pulmonary artery, around the back of the arterial duct, and the end of the right-angle clamp was exposed on the ascending aorta side. The No. 10 line was guided and gently pulled out for double ligation.

This procedure is suitable for intracardiac malformations combined with patent ductus arteriosus.

5. Pulmonary artery closure under extracorporeal circulation

After extracorporeal circulation is established, press the catheter with your fingers or a gauze ball, cool down and reduce the flow, cut the pulmonary artery, and use Prolene direct suture, mattress suture or patch repair according to the size of the catheter under direct vision.

This procedure is suitable for adult patients, patients with severe pulmonary hypertension or patients who were missed before surgery.