Congenital heart disease (CHD) is a cardiovascular malformation caused by a defective or partially arrested development of the fetal heart in the mother’s body and is the most common heart disorder in childhood. The cause of the disease is still unclear and may be related to intrauterine infection during maternal pregnancy, maternal smoking, alcohol abuse, exposure to harmful drugs, environmental pollution and genetic factors. According to statistics, the total number of children with precocious heart disease in China has reached 2.2 million, and 150,000 new cases every year, Hunan Province is a high prevalence of precocious heart disease, the prevalence rate of about 3‰-6‰. Because of the wide variety of precocious heart disease, the lack of specificity of clinical manifestations, many precocious heart disease does not even affect the child’s eating and development, the appearance and healthy children are no different, so it is often not easy to attract the attention of parents, but precocious heart disease is actually a time-limited disease, after a certain age may miss the best time for treatment, or even completely lose the opportunity for treatment, bringing great harm to the affected children and families. At the present stage, there are two treatment methods for precordial disease.
1.Surgical open-chest repair
Direct open-chest, direct visual repair of the heart under extracorporeal circulation. It is characterized by large trauma, general anesthesia and extracorporeal circulation, long hospital stay, and permanent scarring in the chest after surgery, which permanently damages the child’s body, mind and personality and is not conducive to the child’s overall healthy growth;
2.Interventional heart catheterization and blocking of precordial disease
It is a sub-discipline developed on the basis of cardiac intervention in the past 15 years. Through puncturing the femoral artery or femoral vein, inserting a special catheter, sending a special blocker from the peripheral blood vessels to the lesion to be treated, releasing the blocker and fixing it in the lesion to achieve the purpose of cure. The advent of interventional occlusion has brought about a fundamental change in the concept of treatment of congenital heart disease and is now the treatment of choice for most congenital heart diseases. It has obvious advantages: no need to open the chest, no scar without affecting the aesthetics; few complications and high safety; short hospitalization time, usually discharged after 4-5 days of hospitalization; and good treatment effect. After the blocker is implanted, the abnormal blood flow can be completely blocked at that time, and the body’s own endothelial cells will cover its surface in 1 month, and the endothelial cells will completely bury the blocker after 3 months, so the blocker will not fall off.
I. Arterial catheterization
PDA is one of the most common congenital heart diseases, and its incidence accounts for 15%-21% of congenital heart diseases, and is twice as common in females as in males, with one case of PDA occurring in every 2500-5000 surviving newborns. The current indications for PDA occlusion are: PDA of all types with left-to-right shunts aged ≥6 months and weighing 6 kg or more, and not combined with a cardiac malformation requiring surgical treatment. The majority of patients with PDA can be cured by interventional methods.
Atrial septal defect
Atrial septal defect accounts for about 10%-20% of precordial diseases, mainly seen in young children and children, most of the patients develop symptoms only after puberty, especially after 35 years of age, the disease develops rapidly, if not treated in time, pulmonary hypertension will appear, at this time the right ventricle is subjected to left-to-right shunt flow and pulmonary hypertension, so that the right ventricle volume and pressure double overload. With the development of the disease, the patient will experience changes in left ventricular function, which will further aggravate the disease. 1997 saw the invention of the double-disc nickel-titanium alloy blocker, and the efficacy of the percutaneous catheter application of the blocker in the treatment of secondary holes has been confirmed, and interventional therapy has become the treatment of choice for ASD.
The indications for ASD intervention: The “Guidelines for Transcatheter Intervention of Congenital Heart Disease” formulated by the Chinese Medical Association in 2003 stipulate the following indications for ASD intervention
(1) Age: usually ≥3 years.
(2) A secondary foramen ovale type left-to-right shunt ASD of ≥5 mm in diameter with increased right heart volume load, ≤36 mm.
(3) Distance from the edge of the defect to the coronary sinus, superior and inferior vena cava and pulmonary veins ≥5 mm, and ≥7 mm from the atrioventricular valve.
(4) The diameter of the interatrial septum is larger than the diameter of the left atrial lateral umbilical selected for blocking.
(5) No other cardiac malformations requiring surgical intervention are combined.
(6) Post-surgical residual shunt.
Over the past decade of ASD interventions, cases and experience have been accumulated and indications have been broadened, while new insights into ASD interventions have been gained.
1. Patients should be treated as early as possible
The long-term survival rate of patients who underwent surgery before the age of 24 was the same as that of normal controls of the same age, while those who underwent surgery after the age of 40 had a long-term survival rate of only 40% of the normal population and an increased incidence of atrial fibrillation. Therefore, for adult patients with or without symptoms, as long as there is evidence of right ventricular volume loading on ultrasonography, they should be closed as soon as possible.
2. With severe pulmonary hypertension
If the ratio of pulmonary artery pressure to aortic pressure is less than 0.8, and after balloon occlusion, the pulmonary artery pressure decreases by more than 20%, but the aortic pressure does not decrease or does not decrease significantly, and the oxygen saturation increases by more than 90% and the tricuspid regurgitation decreases, it means that the pulmonary vascular bed is reactive, and interventional treatment can be performed.
3.With left heart insufficiency
In ASD patients, due to the long-term right ventricular volume load, the left ventricle can not be fully filled with pressure, the left ventricular myocardium lacks exercise, and the apoptosis of cardiomyocytes, the left heart function will be damaged to varying degrees, after blocking, the left ventricular volume load increases sharply, the left ventricle can not compensate, there will be chest tightness, dyspnea and other signs of left heart insufficiency, and even fatal pulmonary edema. It is generally believed that the rise of the mean pressure of the left atrium is greater than 10mmHg, and it needs to be prevented by drugs, such as tachycardia, dobutamine and milrinone.
Ventricular septal defect
Ventricular septal defect is one of the most common congenital intracardiac malformations, accounting for about 25% of congenital heart disease. With the development of technology, the success rate has been significantly improved and complications have been gradually reduced, however, there are disadvantages such as large surgical trauma, long recovery time and scar left on the body surface. Transcatheter intervention can achieve similar efficacy, but with less trauma and lower complication rate, it has become the preferred treatment for patients with indications.
1. Indications
(1) Diameter of defect: the diameter of the left ventricular surface of perimembranous defect is 3-12mm; if the right ventricular side is porous, the diameter of its large hole should be greater than 2mm; if it is accompanied by a concurrent membrane tumor, the diameter of the left ventricular surface of the defect is 13-18mm as a relative indication, requiring the right ventricular surface to have a small exit and its adhesions are firm.
(2) The distance between the defect edge of the perimembranous part and the right coronary valve of the aorta: eccentric blocker >1.5 mm, symmetric blocker >2.0 mm.
(3) The distance between the defect edge and the right atrioventricular valve: eccentric blocker >2mm, symmetric blocker >1.5mm.
(4) Combination of other cardiovascular malformations that can be treated by intervention.
(5) Post-surgical residual leak.
(6) Mild to moderate pulmonary hypertension without right-to-left shunt.
(7) Myocardial VSD in combination with acute myocardial infarction or trauma-induced myocardial VSD.
(8) Age greater than 3 years and weight greater than 10 kg.
2.Individualized blocking device selection
Generally speaking, myocardial VSD mainly uses myocardial VSD blockers. For myocardial VSD with large left ventricular surface and small right ventricular surface, it may be more reasonable to choose PDA blockers; eccentric blockers are chosen for crestal VSD; the choice of blockers for membranous VSD is very complicated, and symmetrical, asymmetrical (small waist and large side) and eccentric blockers can be chosen, mainly according to the size of the defect, the edge condition, and the distance from the aortic valve, tricuspid valve, and tricuspid valve. It is determined by the size of the defect, the margin, the distance from the aortic valve, the tricuspid valve, the shape of the defect, and the relationship between the size of the entrance and exit. In addition to complete blocking of the VSD, the choice of the blocker should be based on the morphology of the blocker. Under fluoroscopy, the two discs of the blocker should be fully extended, flat, and maintain their initial shape in vitro, with the stainless steel fixation ring on the right ventricular side inside the concave surface and slightly protruding from the outer side of the blocker disc. Ultrasound showed that the blocker was short in length and tightly attached to the sides of the septum. Blindly increasing the diameter of the blocker may increase the risk of postoperative conduction block.
3.Selection of blocker with membranous tumor or porous type
It is difficult to choose the blocking device with membrane tumor, and there is no consensus on the choice of blocking device and whether it is better to block the exit or entrance.
IV. Development trend of congenital heart disease intervention
1, congenital disease treatment strategy has changed most of the treatment of single malformation and compound malformation of congenital disease will be replaced by transcatheter intervention.
2, domestic equipment will play a leading role, benefiting the national population will increase exponentially.
3, the interventional treatment of precordial disease tends to be younger pediatric interventional treatment of precordial disease will become the main body.
4, interventional imaging will have revolutionary progress.