I. Definition: Atrial septal defect (ASD) is a congenital heart malformation caused by atrial septal dysplasia with abnormal traffic between the left and right atria, the incidence is similar to that of ventricular septal defect, which is about 17% in congenital heart disease. Kai Liang, Department of Cardiovascular Surgery, Henan Provincial People’s Hospital
II. Pathological anatomy: According to the location of the defect, there are usually four types.
1.Central type.
2.Inferior vena cava type.
3.Superior vena cava type.
4.Mixed type.
Pathophysiology: Because the left atrial pressure is usually higher than the right atrial pressure, the degree of left-to-right shunt at the atrial level depends on the size of the atrial septal defect
The degree of left-to-right shunt at the atrial level depends on the size of the septal defect and the compliance of the right and left ventricles. The amount of shunt flow is proportional to the size of the defect and the pressure step difference between the left and right atria. With age, spasm of the small pulmonary arteries occurs, followed by progressive intimal hyperplasia and thickening of the middle layer. Pulmonary hypertension is formed.
Clinical manifestations: Before 2 years old, due to the small fractional flow, there are generally no symptoms, the early appearance of dyspnea and easy exertion, some women appear after childbirth, 40-year-old patients can show active panic, shortness of breath, arrhythmia.
V. Signs: Most of the patients have normal growth and development, no cyanosis, large defects appear in the precordial region elevation, heart beat enhancement. A soft systolic murmur can be heard between the 2,3 ribs at the left edge of the sternum, and the second sound in the pulmonary valve area is hyperactive and fixedly split.
The electrocardiogram suggested incomplete right bundle branch block, and cardiac ultrasound suggested atrial septal defect, which was a clear diagnosis.
Surgery: Children within 1 year of age have small fractional flow, asymptomatic and spontaneous healing is about 40%. The ideal age for surgery is 2-4 years old.
VIII. Surgical treatment.
[Indications]
1.The diagnosis of atrial septal defect is clear, and surgery should be performed regardless of whether there are symptoms or not.
2, pulmonary hypertension is still mainly left-to-right shunt, should strive for surgery.
3.Patients with combined heart failure, heart failure should be actively controlled before surgery to create conditions for surgery, and strive for time to actively operate.
4, combined with heart rhythm disorders, should be operated under the condition of drug treatment and control of heart rhythm.
5. Surgery should be performed at any age, but should be performed as early as possible, with preschool age being the most appropriate.
[Contraindications]
Surgery is contraindicated in patients with severe pulmonary hypertension, reverse shunt (right-to-left shunt), and clinical cyanosis.
[Preoperative preparation]
1.If heart failure is present, cardiac and diuretic treatment should be given, and surgery should be performed 3 months after heart failure is controlled.
2.Patients with combined pulmonary hypertension should be treated with vasodilators before surgery to lower the pulmonary artery pressure.
3, combined with heart rhythm disorders, the application of drug therapy.
[Anesthesia]
Endotracheal intubation, intravenous plus inhalation compound anesthesia, usually under hypothermia, extracorporeal circulation for surgery.
[Surgical steps]
1, Position and incision lying down, median sternal splitting incision, longitudinal incision of the pericardium.
2, Cardiac exploration extracardiac exploration for combined malformations, such as ectopic pulmonary vein reflux to the right atrium, left superior vena cava, patent ductus arteriosus and right ventricular outflow tract or pulmonary valve stenosis.
3. Establish extracorporeal circulation.
Figure 1 Types of atrial septal defect
4, Incision of the right atrium with a pulling hook to retract the atrial incision. There are three types of atrial septal defects [Figure 1], and the location of the coronary venous sinus with or without ectopic connections to the pulmonary veins is also determined.
5. Repair of each type of atrial septal defect
2-1 Revealing atrial septal defects
(1) Central type: the defect is located near the oval fossa and can be single or sieve-shaped [Figure 2-1]. The repair method can be direct continuous with interrupted sutures [Figure 2-2]; if the defect is large, the corresponding size of autologous pericardium or polyester cloth can be used for repair [Figure 2-3]. When the direct suture or patch repair is sutured for the last 1 stitch, a saline anesthesiologist should be injected into the left atrium to dilate the lung and fill the left atrium with fluid to exhaust the air in the left atrial cavity before pulling the knot tightly.
2-2 Direct suture method
2-3 Patch repair method
Figure 2 Central type atrial septal defect repair
(2) Venous sinus type: this type of defect is close to the superior vena cava.
Therefore, when repairing the defect, the right atrial incision should be extended to the superior vena cava, and the incision should be made to the border crest. The first stitch should be sewn at the junction of the right atrium and superior vena cava, and the superior vena cava side should be closed with several double-headed stitches, and the rest should be sewn continuously [Figure 3-1 to 5]. This type of defect is prone to combine with ectopic connection of the left superior vena cava and pulmonary veins, and should be carefully examined during surgery.
3-1 Extension of right atrial incision to the superior cavity
3-2 Exposing the venous sinus type atrial defect and part of the pulmonary vein opening in the left atrium
3-3 Continuous suture from the junction of the right atrium and the superior cavity
3-4 Suture the patch at the anterior and posterior edges respectively
3-5 Completion of the repair
Figure 3 Repair of venous sinus type atrial septal defect
(3) Inferior cavity type: this type is a low level defect with an absent inferior margin. Therefore, the next most suture should be sutured to the left atrial wall tissue [Figure 4].
Figure 4 Repair of inferior cavernous type atrial septal defect
(4) With partial pulmonary vein ectopic connection: if the atrial septal defect is large enough, the other edge of the defect can be sutured directly to the right atrium where the pulmonary vein opens [Figure 5-1]; if the defect is small, it can be enlarged and then sutured; if the direct suture is deformed in tension and even causes pulmonary vein obstruction, a patch repair should be applied [Figure 5-2].
Figure 5 Repair of atrial septal defect with right pulmonary vein ectopic connection
IX. Internal medicine intervention
1, age should be greater than 3 years, less than 60 years, and weight greater than 5 kg
2, secondary foramen atrial defect with maximum extension diameter less than 40; margin at least 4 mm;
3, atrial septal diameter greater than 14-16mm atrial septal defect;
4, Atrial defect left after complex congenital heart disease surgery: Fontan operation;
5, Residual shunt or recanalization after secondary atrial defect surgery;
6, clinical manifestations of right ventricular volume overload.
Internal intervention is contraindicated for
1, with other cardiac malformations;
2. Primary atrial defect;
3, severe pulmonary hypertension, Eisenmenger syndrome;
4, venous occlusion due to venous thrombosis of the lower extremities;
5. Systemic factors such as: infection, etc.
Ten, post-operative precautions: after successful surgery, the child and normal children live and learn, pay attention to the post-operative 3 months to avoid strain, avoid colds. Strengthen nutrition. Do not inject vaccines within 1 month after surgery.