Congenital heart disease is one of the most common congenital anomalies. There are 150,000-200,000 new cases each year, with a prevalence of 0.8% . The most common congenital heart diseases include ventricular septal defect, atrial septal defect, and patent ductus arteriosus. Traditional treatment of precordial disease requires open-heart surgery under extracorporeal circulation, with a surgical incision of about 20 cm, which often leaves significant surgical scars and stimulates inflammatory reactions in the patient’s body, destroys blood cells, causes disturbances in coagulation and the internal environment, and leads to corresponding complications.
With the development of economy and continuous progress of science and technology, the treatment effect and safety of pediatric congenital heart disease have been greatly improved. For this reason, people also put forward high requirements for the reduction of surgical trauma and the cosmetic effect of surgery under the premise of pursuing safety and obtaining good treatment effect. Therefore, a new cardiac surgery technique, minimally invasive cardiac surgery, was born and has been greatly developed in the last decade.
I. Minimally invasive small incision
The traditional concept of cardiac surgery is “big surgery with big incisions”, and the median incision with longitudinal splitting of the sternum is the conventional approach to direct intracardiac surgery. However, it also has many disadvantages, such as large trauma, high blood loss, easy incision and sternal infection, and high incidence of pectus excavatum and funnel chest in children after surgery.
Moreover, the anterior chest incision scar affects the aesthetics and produces permanent mental trauma to patients, especially girls. One of the starting points of minimally invasive cardiac surgery is to shorten the length of the surgical incision as much as possible, which is called tiny incision, or change the access route to make the incision more concealed or more aesthetic.
1, small axillary incision surgery for pediatric congenital heart disease has less trauma, less blood loss, faster postoperative recovery, hidden incision, and thus also has better cosmetic effect. For simple congenital heart disease, atrial defects, small ventricular defects, and arteriovenous ductus arteriosus. However, this incision is more demanding for the surgeon, who has to be very skilled in dissection and operation. When poorly exposed, it is difficult to operate in overly complicated cases.
2. The small incision in the lower sternum for direct intracardiac surgery effectively solves the problem of small incision and good visualization. The injury is small, the pain is light, the thorax is not deformed, and the scar is usually not revealed in low chest clothes. The incision can be extended if complications arise.
Disadvantages are.
The small incision in the lower sternum is poorly exposed to the base of the heart and large vessels due to the inferior incision, so the key to the procedure is successful aortic cannulation and establishment of extracorporeal circulation;
Advantages.
This method has the following advantages.
①Small incision and low position, in line with the aesthetic point of view;
②Keeping the upper part of the sternum intact and thoracic stability, reducing postoperative incisional pain and facilitating the recovery of respiratory function;
③No damage to the lung, reducing pulmonary complications;
④No femoral artery cannulation is required, which reduces the chance of contamination;
(5) shallow field, good exposure, easy to grasp operation, and no prolongation of operation time;
⑥Small sternal incision, small posterior sternal trauma, and less blood loss;
(7) In children, the rib cartilage of the sternum is flexible, so there is no need to transect the sternum and the internal mammary artery will not be injured;
⑧Easy to expand into a conventional median incision according to the need.
II. Interventional treatment
Percutaneous catheter interventions for precardiac disease began in the mid-20th century, and in 1997, Amplatzer developed a new generation of blockers made of nickel-titanium alloy and used them in clinical practice, which significantly improved the safety and success rate of interventions for precardiac disease.
At present, the main precordial diseases that can be cured by this interventional method are: patent ductus arteriosus (PDA), atrial septal defect east (ASD), ventricular septal defect (VSD), pulmonary arteriovenous fistula, coronary arteriovenous fistula, heart valve disease (including pulmonary stenosis and regurgitation, aortic stenosis, mitral stenosis, tricuspid stenosis, etc.) and congenital aortic constriction. Among them, interventional treatment of common precardiac diseases such as PDA, ASD and VSD has reached a mature stage.
Advantages of interventional treatment of precardiac disease compared with surgery.
1.No incision is needed on the chest and back, and only a needle eye (about 3mm) is left in the groin.
2, treatment without the implementation of external circulation, low-temperature anesthesia. Children only need basic anesthesia without intubation to cooperate, and older children only need local anesthesia.
3.Because of the low bleeding of interventional treatment, blood transfusion is not required, thus avoiding the possible adverse reactions caused by blood transfusion.
4.Compared with conventional surgical procedures, interventional treatment has a shorter operation time, shorter hospital stay and faster postoperative recovery. Generally, drinking starts in about 30 minutes to 1 hour, and the patient can get out of bed in 20 hours after surgery, and can be discharged in 1-3 days after hospitalization, and children with local anesthesia can be completed in an outpatient clinic.
Minimally invasive surgical occlusion for congenital heart disease is now on the rise, avoiding radiation damage, contrast hazards, and small restrictions on peripheral vessels while greatly improving the success rate and reducing complications of occlusion. We have developed percutaneous atrial defect blocking, transthoracic ventricular defect, atrial defect and arteriovenous ductus arteriosus blocking, which are the best choices for children with congenital heart disease.
Third, the development of combined interventional surgery (Hybrid technology)
In the previous years, there was a debate about the advantages and disadvantages of interventional therapy and surgery, but now, it is increasingly recognized that these two techniques can actually be integrated organically. The hybrid technique was born in this context, and it is a perfect combination of surgical techniques and interventional treatments, whose advantages include.
① non-invasive, less traumatic, less painful, safer, and faster recovery.
②High accuracy and high success rate.
③No age limit.
④Reducing the application of blood products.
1.Atrial septal defect and ventricular septal defect
In most developing countries, infants and children under 3 years of age are rarely treated by percutaneous interventional occlusion due to the unavailability of small-sized interventional catheter materials. Open-chest Hybrid surgery fills the gap in this age group and demonstrates the superiority of Hybrid technology. It has the advantages of short operation path, time saving and high success rate, no limitation of age and weight, and easy conversion to direct intracardiac correction in case of failure.
Ventricular septal defect is the most common congenital heart disease in clinical practice. Although conventional surgical treatment is very mature, it is relatively more traumatic, and interventional therapy prefers to use a larger blocker model because of the fear of blocker dislodgement, which makes the heart conduction system vulnerable to compression. In contrast, our transthoracic small incisional blocker for congenital heart disease ventricular septal defect has the following advantages.
1. Less traumatic surgery, avoiding the blow to the heart from extracorporeal circulation, and fast postoperative recovery;
2. A more suitable size of blocker can be used, which makes the probability of heart conduction block smaller and safer; 3. The path is short, which can avoid damage to tricuspid tendon, etc. The indications are: children with simple ventricular septal defect, weight >8 kg, ventricular defect type including perimembranous, intramural, inframembranous and myocardial ventricular defects, defect range of 3-8 mm, the upper edge of the ventricular defect is ≥2 mm from the right aortic coronary valve, no right aortic coronary valve prolapse into the ventricular defect and aortic regurgitation, and no combined pulmonary hypertension.
2.Pulmonary atresia/severe pulmonary stenosis in neonates and small infants with intact ventricular septum. These children can develop severe hypoxic cyanosis, feeding difficulties and cardiac failure early after birth, and if allowed to develop, a significant proportion of them can die within one month after birth. If the obstruction is relieved in time, it will not only improve the symptoms of hypoxia, but also promote the development of pulmonary artery and right ventricle. Compared with conventional surgery and percutaneous pulmonary valve balloon dilatation and angioplasty, hybrid surgery (i.e., transthoracic pulmonary valve balloon dilatation and angioplasty) has the following advantages:
(1) Prevention of peripheral vascular injury;
(2) Avoidance of injuries associated with extracorporeal circulation, faster postoperative recovery, and shorter monitoring and endotracheal intubation times;
(3) Higher safety, if there is tissue tear and bleeding, serious arrhythmia or even cardiac arrest or other accidental injury during dilatation, it can be dealt with in time under direct vision;
(4) In patients with poorly developed right ventricle and pulmonary artery, body-pulmonary bypass can be performed at the same time to improve the prognosis of patients;
(5) If the dilatation is unsatisfactory, right ventricular outflow tract obstruction can be transferred to extracorporeal circulation for right ventricular outflow tract dissection at the same time to avoid secondary surgery. This technique has a low perioperative mortality and complication rate; the incidence of pulmonary valve restenosis and pulmonary regurgitation at midterm follow-up is also low, and most of them can be cured without further intervention.
3.Cyanotic congenital heart disease with obvious side branches of the body lung
Cyanotic heart disease (including tetralogy of Fallot, pulmonary atresia, etc.) is usually due to low pulmonary blood flow, compensatory formation of body-pulmonary collateral branches, these body-pulmonary collateral branches to reduce the symptoms of hypoxia in children before surgery, and some children even rely on the collateral blood supply to survive, and the collateral branches can be circulated to maintain life before surgery. However, if the side branches are still present during and after surgery, it will not only make the operation more difficult, but also cause great damage to the patient’s heart and lungs, so the side branches need to be blocked before doing the operation.
Since it is difficult for surgeons to find the side branch vessels of the body lung during surgery. Therefore, a “one-stop” hybrid operating room with both cardiovascular imaging and surgical equipment is the best way to perform cardiovascular imaging and surgery at the same time.
4.Aortic stenosis combined with ventricular septal defect in small infants
Infants with aortic stenosis combined with ventricular septal defect have early onset of severe pulmonary congestion and severe pulmonary hypertension, often manifested as feeding difficulties, low body weight,
It often presents with feeding difficulties, low body weight, recurrent respiratory infections and heart failure, and therefore requires early surgery. Currently, most surgeons use a median incision to remove the aortic constriction and repair the ventricular defect in a single surgical procedure, but this requires deep hypothermic arrest of circulation and local cerebral perfusion, which results in a long operative time, major trauma, and slow postoperative recovery.
In order to improve the outcome of these children, the Hybrid technique was used to correct aortic stenosis combined with ventricular septal defect in small infants in a single stage transthoracic procedure, incorporating balloon dilation into cardiac surgery for the first time. Compared with percutaneous balloon angioplasty, the procedure is significantly simpler and avoids the problems of restricted transcatheter pathways and femoral artery injury. Compared with conventional surgical procedures, it can simplify the operation, eliminate deep hypothermic arrest or local cerebral perfusion, significantly shorten the operation time and promote postoperative recovery.
In addition to the above series of hybridization techniques, there are other products and techniques related to hybridization of precardiac disease currently under development, which are believed to be applied in the near future for the benefit of children. For example, the pulmonary artery with valve stent, which is placed in the position of pulmonary valve through a small sternal incision, can reduce the risk of secondary surgery in children with severe pulmonary valve closure insufficiency in the distant period after the correction of tetralogy of Fallot.
IV. Thoracoscopic and robotic-assisted congenital heart surgery
The application of TV thoracoscopy and robotics in cardiac surgery has only a few years of history, and only a few units have carried out this technology so far, and the number of surgical cases performed is still small. Although there are still some disadvantages of this technology, such as more complicated operation, longer time, not suitable for infants and children, and higher economic cost. However, compared with traditional cardiac surgery, it still has superiority. With the accumulation of experience and the increasing maturity of doctors’ surgical operation techniques, the operation time will be significantly shortened, and thoracoscopic and robot-assisted congenital heart surgery will definitely be welcomed by the majority of patients and physicians.
V. Minimally invasive extracorporeal circulation technology
The defects of traditional extracorporeal circulation.
1, hemodilution, excessive dilution of blood components not only affects the gas transport dependent on red blood cells, but also affects platelets, coagulation dependent on body fluid factors, and intravascular colloid osmotic pressure dependent on plasma proteins, thus affecting hemodynamic stability;
2.Contact between blood and foreign body surface, causing activation of coagulation and fibrinolytic system, activation of complement, release of bradykinin, causing inflammatory reaction;
3.It causes platelet depletion and partial protein denaturation, resulting in increased complications such as early to mid-term postoperative stroke and neurocognitive dysfunction.
Minimally invasive extracorporeal circulation has greatly improved the defects of traditional extracorporeal circulation. Its characteristics are:
①miniaturization, small prefilling volume, and low hemodilution;
(2) It has surface coating, good biocompatibility, and mild inflammatory reaction;
(3) airtight and with venous venting system to avoid blood gas interface;
④The blood is returned to the field after treatment;
⑤ Easy installation and high flexibility.
Current research findings indicate that the use of minimally invasive extracorporeal circulation devices has important clinical implications: reduced postoperative bleeding; reduced need for red blood cells, platelets and fresh plasma; reduced time on ventilators; reduced ICU stay; and reduced patient care costs.
Minimally invasive cardiac surgery represents a future development trend, and its gradual promotion in the world in recent years is a sign of its strong vitality. Minimally invasive surgery is a sublimation of surgical science, which should have the best internal environment, the smallest surgical incision, the lightest systemic inflammatory response, and the smallest scar. Moreover, any technique has its advantages and disadvantages, and the key depends on which method is more beneficial to the recovery of the child, with the aim of achieving the safest and most satisfactory results.