Congenital heart disease is the most common type of heart disease that seriously endangers pediatric health. In the last decade, great progress has been made in the treatment of congenital heart disease in both internal and surgical aspects, including targeted treatment, interventional treatment, surgical palliative and radical surgery, inlay treatment, minimally invasive surgery and heart transplantation. This article reviews the progress of research on the comprehensive treatment of congenital heart disease. Congenital heart disease is one of the most common heart diseases that seriously endanger pediatric health, with an incidence of about 7-10/1000 in live births; currently, there are about 150-200,000 newborn children with congenital heart disease in China every year. Therefore, the comprehensive medical and surgical treatment of precocious heart disease has received increasing attention.
I. Classification
(a) Precardiac disease can be divided into three categories according to anatomical and hemodynamic characteristics: left-to-right shunt type, right-to-left shunt type and no shunt type. Common left-to-right shunt type CHD: atrial septal defect (ASD), ventricular septal defect (VSD), patent ductus arteriosus (PDA), pulmonary vein ectopic drainage, etc. Right-to-left shunt CHD: tetralogy of Fallot (TOF), complete transposition of the great arteries (D-TGA), tricuspid atresia (TA), pulmonary artery atresia (PA), patent ductus arteriosus (PTA), single ventricle (SV), and Eisenmenger’s syndrome. CHD without shunt: aortic constriction (COA), pulmonary stenosis (PS), mitral regurgitation (MR), etc.
(B) Precardiac disease is classified into cyanotic and non-cyanotic according to the presence or absence of cyanosis in clinical practice. Cyanotic CHD includes severe TOF, D-TGA, TA, PA, etc.; non-cyanotic CHD: early to mid-stage ASD, VSD, PDA, etc.
(C) Classification of precardiac diseases according to the time of clinical onset: those with onset mainly in the neonatal period: PA, PTA, D-TGA, TA, obstructive complete pulmonary venous ectopic drainage (TAPVC), hypoplastic left heart syndrome (HLHS), etc. Those that develop mainly in infancy: large VSD, PDA, TOF, SV, complete atrioventricular access (CAVC), pulmonary artery atresia with large ventricular septal defect (PA/VSD), double right ventricular outlet (DORV), main-pulmonary septal defect, etc. (A-P-W). Predominantly in early childhood and later onset: small VSD, ASD, COA, partial atrioventricular access (PAVC), partial pulmonary venous ectopic drainage (PAPVC), etc.
II. Treatment
(I) General treatment
Patients with congestive CHD are prone to recurrent respiratory tract infections in the early stage, causing impairment of cardiac and other organ functions, so preoperative diuresis, cardiac strengthening and vasodilatation are necessary; those with obvious preoperative malnutrition and growth retardation can be given appropriate nutritional support; postoperative situation allows, enteral feeding via oral or nasal feeding tube should be implemented as far as possible to reduce the occurrence of complications.
(B) Targeted treatment
1, the arterial duct is not closed for relying on the arterial duct opening of the neonatal period CHD such as pulmonary atresia without collateral circulation, preoperative arterial duct should be kept open, intravenous drip prostaglandin E; arterial duct is not closed resulting in increased pulmonary blood flow in preterm infants with cardiac insufficiency, anti-inflammatory pain can be used to promote the closure of the arterial duct.
2. Hypoxic attacks occur in TOF and DORV with right ventricular outflow tract stenosis; they are mostly seen in the first 2-6 months of life and manifest as rapid breathing, increased cyanosis, and increased heart rate. Treatment: Place the child in knee-chest position, administer oxygen, intramuscular or intravenous morphine, slow intravenous sodium bicarbonate, and if necessary, Neoforin to raise aortic blood pressure. frequent episodes of TOF hypoxia are indications for emergency surgery.
3, CHD combined with pulmonary hypertension For children with CHD who have developed pulmonary hypertension, such as large VSD or PDA, PTA, A-P-W, CAVC, DORV, etc., preoperative and postoperative drugs to reduce pulmonary artery pressure, such as vancomycin, vantave, bosentan, nitric oxide and other vasodilators, should be used to assist surgical treatment to smooth the perioperative period.
(C) Interventional treatment
1.Arterial catheter occlusion arterial catheter interposition occlusion includes spring ring method and Amplazer method. Indications: left-to-right shunt of the arterial catheter and not combined with other intracardiac malformations, post-surgical residual fraction, narrowest diameter of the arterial catheter ≥ 2mm, age ≥ 6 months, weight ≥ 4kg.
2, atrial septal defect sealing indications: secondary hole central type ASD, diameter ≤ 30 mm, notch edge with ≥ 5 mm of septal tissue, edge from the coronary sinus orifice, mitral valve, tricuspid valve and pulmonary veins are ≥ 5 mm or more; the waist diameter of the sealing device should be larger than the measured ASD diameter of 1-2 mm. 6 months of postoperative oral anticoagulation with small doses of aspirin is required.
3. Indications for ventricular septal defect occlusion: Most VSDs are not suitable for interposition occlusion because of the proximity of the defect location to the conduction bundle or aortic valve. The mortality rate of surgical operation for myocardial VSD is high, and the postoperative complications are also high, so medical interposition occlusion is an effective treatment method.
4, pulmonary valve balloon dilatation indications: pulmonary artery a right ventricular pressure difference > 40mmHg. In neonates with severe pulmonary stenosis, balloon dilatation of the pulmonary valve is required if the right ventricular volume is above 50%-60% of normal or >30 ml/m2 and the tricuspid annulus diameter is >11 mm.
5, Indications for aortic arch narrowing balloon dilation: upper extremity hypertension, differential pressure at the narrowing >30 mmHg; first choice for postoperative restenosis; aortic balloon dilation is effective in 80% to 90% of cases of unoperated aortic arch narrowing and postoperative restenosis.
6, vascular spring coil embolization indications: severe pulmonary ischemic CHD such as severe TOF, PA/VSD and other body-pulmonary arteries between the collateral vessels (MAPCAs), Fontan surgery before and after the collateral circulation, B a T shunt after the huge body-pulmonary collateral circulation embolization. The common spring coil is Gianturco coil, and Detachable coil can be used for larger arteriovenous fistulas.
(iv) Surgical treatment
With the improvement of preoperative diagnosis, surgical techniques, extracorporeal circulation and perioperative monitoring and treatment of CHD, surgical treatment is now preferred in infancy and early childhood to avoid irreversible damage to the myocardium; the indications and surgical methods for radical surgery for different types of CHD are different. At present, about half of the surgeries in complex CHD abroad are completed within the first 6 months of life.
1.Surgical treatment of simple CHD
1.1 Ventricular septal defect (VSD) VSD with mild symptoms can be postponed to preschool age; large VSD with uncontrollable pneumonia or heart failure should be operated early; 6 months-2 years old although heart failure and pneumonia are controlled, but the progressive increase of pulmonary artery pressure in children, it is appropriate to operate early; sub-stem VSD is prone to aortic valve prolapse, it is appropriate to operate early; repair materials using multiple autologous pericardium; surgery The route: pulmonary arteriotomy and right atriotomy.
1.2 Atrial septal defect [ASD(II)
Small ASD(II) with mild symptoms alone can be followed up until school age; early surgery is recommended for large ASD(II) with recurrent pneumonia or heart failure, or progressive increase in pulmonary artery pressure, or in combination with other cardiac malformations. Surgical incision: right axillary opening or median opening; ASD(II) can be repaired with direct sutures or patches.
1.3 Large PDA with recurrent pneumonia or heart failure in infants and children with patent ductus arteriosus (PDA), early surgery is recommended. If combined with infective endocarditis, a combination of surgery and anti-inflammatory therapy is required. There are three surgical methods: thoracoscopic, non-extracorporeal circulation and extracorporeal circulation closure.
1.4 Pulmonary stenosis (PS) is followed up for mild symptoms; surgery is required for right ventricular and pulmonary artery pressure difference ≥ 40 mmHg; early treatment is required for severe cases (≥ 90 mmHg); emergency surgery under direct vision is recommended for those with particularly severe stenosis or simultaneous critical conditions with other cardiac malformations.
1.5 For aortic constriction (CoA) with mild symptoms, surgery should be postponed to 4-6 years of age; for those with respiratory distress, poor growth and development, associated heart failure, ineffective medical treatment, and pressure difference between the two ends of the stenosis ≥ 30 mmHg, surgery should be performed in one stage regardless of age. Methods: Simple COA can be done through a left posterior lateral chest wall skin incision into the chest, or through a median sternal incision if combined with other CHDs.
2.Surgical treatment of complex CHD
At present, it is believed that most CHDs, including many complex CDHs, can be treated with one-stage radical surgery; for some complex CHDs, only palliative surgery can be performed if there is no indication for radical treatment. Common palliative surgical methods include those that increase pulmonary blood flow such as body-pulmonary artery bypass including modified Blalock-Taussig, Potts and Watrston procedures; Glenn bypass, staged Fontan procedure, etc., and palliative procedures that reduce pulmonary blood flow such as pulmonary artery circumferential reduction (P-A Banding, PAB).
2.1 Body-pulmonary artery shunts include: ① Modified Blalock-Taussig procedure: i.e., artificial vessels are used to bypass the anastomosis between the right innominate artery and the right pulmonary artery. The Potts procedure and the Watrston procedure are rarely used now. Indications: Complex cyanotic CHD that cannot be corrected or has a high mortality rate in infancy for one-stage radical treatment, such as PA, severe TOF, etc.
2.2 Glenn shunt is to introduce blood from the superior vena cava directly into the pulmonary artery to increase oxygenated blood in the lungs and, at the same time, reduce the burden on the right ventricle by 35-45%. Indications: Severe ischemic CHD in pulmonary circulation, such as tricuspid atresia, severe TOF, PA, etc.; well-developed pulmonary artery branches, pulmonary artery pressure below 4Wood units; not recommended for neonates.
2.3 Indications for pulmonary artery annuloplasty (P-A Banding): mostly applied to cyanotic CHD with increased pulmonary blood, such as ventricular double inlet, tricuspid atresia without pulmonary stenosis; children who need to undergo second-stage rapid aortic reversal; combined with clinical studies in recent years this procedure should be chosen with caution.
2.4 The Rastelli procedure is also known as right ventricle-pulmonary artery connection with a valve. Because artificial valve vessels are prone to calcification and blockage, homogeneous or heterogeneous valve tubes are mostly used nowadays. Indications: PTA, PA, DORV with PS, corrective transposition of the great arteries (L-TGA) with PS, etc.
2.5 Lecompte procedure (REV procedure) This procedure is performed by introducing the left ventricular blood through the VSD into the aorta with the aid of an internal tunnel, and connecting the free and drawn down autologous main pulmonary artery directly to the right ventricle without an external conduit, which can grow with age, and the total pulmonary artery trunk should be of sufficient length. Indications: D-TGA/VSD with PS, DORV (VSD away from the aorta) with PS, etc.; internal tunnel material is mostly homogeneous, heterogeneous pericardium or artificial material.
2.6 Aortic switch (Switch or Jatene procedure), i.e., the abnormal aorta is disconnected from the pulmonary root valve under deep hypothermia and crossed and transposed anastomosis to the normal anatomic position; the age of the procedure depends on the presence or absence of VSD to avoid degeneration of the left ventricular myocardium and the generation of pulmonary hypertension. Indications: TGA with good development of both ventricles and aorta, good function of each valve, and normal coronary artery position; not suitable for children with ventricular outflow tract or PS.
2.7 Nikaidoh procedure, in which the aorta is dissected and grafted together with the valve under deep hypothermia and reanastomosed to the dissected left ventricular outflow tract, generally without coronary artery graft. Indications: Children with D-TGA with subaortic septal defect and combined pulmonary stenosis.
2.8 Double-Switch is an intra-atrial switch that allows the right atrium to connect to the anatomic right ventricle and the left atrium to the anatomic left ventricle, with a large vessel switch or intra-ventricular tunnel that allows the left ventricle to connect to the aorta and the right ventricle to connect to the pulmonary artery, with the left ventricle and mitral valve assuming body circulation and anatomic correction; indications: for children with L-TGA, such as L-TGA/VSD, right or left ventricular double outlet of L-TGA.
2.9 Second-stage rapid aortic reversal, i.e., pulmonary artery circumferential reduction and simultaneous body-pulmonary artery bypass; because of the decrease in left ventricular pressure in children with intact ventricular septum D-TGA, in order to tolerate left ventricular function after aortic reversal, the left ventricle must obtain rapid forging, and then perform second-stage aortic dissection correction after 7-10 days. It is indicated for D-TGA without VSD and without timely aortic transposition within 2 – 3 weeks of birth.
2.10 Fontan-type procedures include vena cava-a-pulmonary artery end-lateral bidirectional bypass, semi-Fontan-type procedures, and full Fontan-type procedures. There is another type of 1 1/2Fontan procedure, which is a bidirectional bypass of the vena cava and pulmonary artery with simultaneous repair of intracardiac malformations. Indications: Currently, it is commonly used to correct single ventricle, Ebstein’s malformation, and hypoplastic left heart syndrome; the surgical results are closely related to the surgical indications.
2.11 The Norwood procedure is a staged Fontan procedure. In the first stage of surgery, the main pulmonary artery is cut, its proximal end is connected to the ascending aorta, and its distal end is connected to the subclavian artery or to the aorta to establish the right ventricle-aortic channel and the main pulmonary artery channel, and the atrial septum is removed; in the second stage of surgery, a modified Fontan procedure is performed. It is indicated for large vessels or with other cardiac malformations in cases of dysplasia from the ascending aorta to its descending arch.
In addition, intra-atrial flow conversion (also known as Mustand and Senning) and “monogenization” surgery are rarely used because of the high incidence of postoperative arrhythmias or high mortality.
(V) Medical and surgical mosaic treatment
That is, for small infants with myocardial ventricular defects, surgical open-heart surgery is used to guide the wire through the right ventricular surface to the left ventricle (via esophageal ultrasound positioning), and then a blocking umbrella is placed by a cardiologist. In recent years, Columbus Children’s Hospital in the United States has achieved good results in children with HLHS treated with mosaicism; the surgery is divided into 3 stages; stage 1 is a neonatal cardiac surgeon opening the chest, a cardiologist placing a stent in the arterial duct and atrial septum, and then a surgeon making a loop reduction in the left and right pulmonary arteries; stage 2 surgery is a new aortoplasty and semi-Tontan after 2 months; stage 3 surgery is around 2 years of age The Fontan procedure is performed by an internist who places a catheter through the internal jugular vein and a femoral vein to create a “track” where a special expandable stent is placed in the appropriate position to release and form an internal conduit. It is also suitable for single ventricle patients.
(vi) Minimally invasive treatment
Minimally invasive cardiothoracic surgery in a broad sense includes non-traditional pathways into the chest, thoracoscopic-assisted surgical treatment, and open-heart-free extracorporeal circulation, etc.
1.Small right lateral incision and small anterior median thoracic incision This method includes small incisions in the right axilla, right anterior lateral thorax and median sternum. It is suitable for slightly older patients with simpler cardiac deformities; most of them use small anterior median chest incision or right lateral open chest, with hidden surgical incision, small trauma, fast recovery of cardiopulmonary function after surgery, and cosmetic value; it also has potential risks, and once any change occurs during surgery, emergency measures should be taken, such as expanding the surgical incision or changing to median sternal incision. Beijing Fu Wai Hospital and Shanghai Children’s Hospital have achieved good results.
2.Thoracoscopy is mainly used for extracardiac surgery, such as the clamping of arterial ducts and the blocking of thicker body-pulmonary collateral vessels in complex precordial disease; it is used for intracardiac exploration of parts not easily seen directly during surgery, such as the localization and repair of myocardial ventricular defects; surgical correction of diseased mitral valves or aortic valves can be performed.
(vii) Heart transplantation
Heart transplantation has been performed since the 1980’s. It consists of two major categories: 1) secondary heart disease, such as dilated cardiomyopathy; 2) congenital heart disease, including patients with complex malformations that cannot be corrected surgically, end-stage CHD heart failure, left heart dysplasia, or deteriorating postoperative conditions. Currently, the United States has the largest number of pediatric heart transplants in the world, with a 5-year survival rate of 72%, but the biggest problem is the small number of donor sources and other much-needed improvements.