I. Background
China is one of the countries in the world with a high incidence of congenital heart disease (congenital heart disease for short), with about 150,000-177,000
million patients with congenital heart disease are born each year, and about 100,000 patients need surgical treatment. Since the successful ligation of patent ductus arteriosus by Gross et al. in 1938, surgical treatment of congenital heart disease has made great progress, allowing the majority of patients to be treated in a timely manner. However, surgery requires open-heart, or (and) extracorporeal cardiopulmonary diversion, surgical complications, and cosmetic problems associated with surgical scarring. These prompted attempts to replace surgery by inserting various catheters and devices from the peripheral vasculature to the cardiovascular cavity to be treated through a non-open route, which developed into interventional catheterization. Due to the wide variety of precardiac diseases, varying pathological types, age and severity of disease, and hemodynamics, postoperative follow-up and comparative studies with surgical procedures have been performed. Although transcatheter interventions have the advantages of better aesthetics, less trauma, avoidance of extracorporeal circulation and shorter hospitalization days, they may still be accompanied by serious complications such as thromboembolism, vascular injury, and even cardiac perforation, and there is a deep understanding of the problems as well as limitations. In recent years, minimally invasive cardiac surgery (MICS) has developed rapidly, and now minimally invasive parachute blocking with small incisions in the chest has been widely used in the treatment of pediatric congenital heart disease (CHD).
II. Historical review of interventional treatment for pediatric congenital heart disease
Transcatheter intervention for congenital heart disease began in the middle of the 20th century. In 1976, Rashkind invented the umbrella closure device and successfully treated atrial septal defects (ASDs) with sealing; in 1982, Kan first reported balloon dilation for pulmonary artery braid stenosis, followed by Lababidi’s successful balloon dilation of the aortic braid in 1984; In 1988, Lock et al. first applied the Rashkind double-sided umbrella to close VSD, and in 1989, Lock et al. designed a double-umbrella occluder called the Clamshell occluder to close ASD, but a high residual shunt rate was found in clinical trials.
In 1990, Sideris applied a button-type double-disc occluder system device to close ASD, but it was not popularized due to the complicated operation and high residual shunt rate. 1992, Combier et al. first reported the success of using spring ring to occlude PDA, and then it was popularized in China and abroad; Amplatzer developed a new generation of occluder with nickel-titanium alloy braid in 1997 and used it in clinical use. The “waist” of the device matches the diameter of the ASD, which makes the plugger less likely to be displaced. The use of this type of blocker is easy to operate and the delivery sheath is thin, which makes it suitable for ASD blocking in pediatric patients, thus significantly improving the safety and success rate of the interventional treatment for precardiac disease. In addition, the localization of interventional devices for precardiac disease has played a positive role in promoting the interventional treatment of precardiac disease in China.
In 1997, Amin et al. first introduced the technique of transventricular blocking of ventricular septal defects based on animal studies of myocardial and membranous ventricular septal defects, and successfully operated on an infant with a myocardial ventricular septal defect under non-extracorporeal circulation. In 2002, Yu Shiqiang et al. were the first to report a large number of cases of atrial septal defect occlusion with a small transthoracic incision and umbrella piece under non-extracorporeal circulation. In 2007, Diab et al. reported the use of Amplatzer umbrella to seal the atrial septal defect via the right atrium. In the same year, Li Hongxin also reported the experience of 100 cases of intraoperative closure of atrial septal defects with the parachute device via a small right anterior thoracic incision.
Small thoracic incision for non-extracorporeal circulation atrial septal defect (ASD) occlusion
Atrial septal defect is one of the common congenital heart diseases, and its incidence accounts for about 6-10% of congenital heart diseases. There are primary orifice type and secondary orifice type, 84% of which are secondary orifice type ASD, and those who can be cured by interventional means are secondary orifice type ASD.
1. Indications for surgical occlusion of ASD:
(1) age >1 year, weight >8Kg; (2) ASD diameter 5mm-34mm; (3) defect edge to coronary sinus, upper and lower vena cava and pulmonary vein opening distance >5mm, to atrioventricular braid distance >7mm; (4) septal diameter is greater than the diameter of the selected blocker left atrial lateral disc; (5) not combined with other cardiac malformations that must be surgically operated. With the maturation of surgical occlusion techniques, the age of surgery can be relaxed to infants less than 1 year old. In contrast, the following conditions are contraindicated for ASD intervention:
(1) Primary foramen ovale ASD and venous sinus ASD;
(2) Patients with combined endocarditis and hemorrhagic disease;
(3) thrombosis at the placement of the blocker and thrombosis at the catheter insertion route;
(4) Severe pulmonary hypertension resulting in right-to-left shunt;
(5) Patients with other serious myocardial disorders or heart braid disease.
2. Surgical methods.
2.1 TEE guidance: The procedure is performed under intravenous complex anesthesia with tracheal intubation. The patient is placed in a supine position with the right chest elevated 30 degrees, and the esophageal ultrasound probe is placed. The two-chamber section of the atrium, the four chambers of the apex and the short-axis section of the great vessels are observed on transesophageal echocardiography (or subxiphoid chest wall ultrasound).
2.2 Umbrella piece type selection: The double-disc umbrella piece blocker is the same as the blocker used in the transcatheter route in internal medicine. If the shape of the ASD is round or round-like; choose the maximum ASD diameter plus 4 mm, if the ASD is oval, choose the longest ASD diameter plus ≥ 4 mm; if it is a double-hole ASD, choose the model of the umbrella piece as the sum of the maximum ASD diameter and the distance between the two holes plus 4 or 6 mm.
2.3 Placement of the blocker: routine disinfection and towel laying, small incision of 2-2.5 cm next to the sternum in the fourth intercostal space of the right anterior chest, layer by layer through the intercostal space into the chest, “H”-shaped incision of the pericardium, both sides hanging. The right atrium was double loaded with heparinized 1mg/kg and the blocker was soaked with heparinized saline for 1min. The right atrial incision was made and the sheath was inserted. Under the guidance of ultrasound esophageal probe, the sheath was inserted into the left atrium through the atrial defect and the blocker was pushed forward to open the blocking umbrella on the left atrial side, pulling back the umbrella to cover the left atrial side of the atrial septal defect. The position of the blocker was normal without dislodgement in the pull-back boost test. The left-to-right shunt disappeared, and the mitral and tricuspid orifices and the right pulmonary vein opening in the upper and lower vena cava were not affected by the color test. The blocker was released by rotating the detachment transfer wire, and the lead was cut and withdrawn after confirming the normal position of the blocker by cardiac ultrasound. The right atrial ruffle was tied without bleeding. No neutralization of heparin, sutured intercostal, intraoperative chest venting, routine chest closure, no need to place closed chest drainage tube.
3.The advantages of surgical non-extracorporeal circulation atrial septal defect sealing.
(1) Wide surgical indications, especially for younger infants and children, it is not necessary to place a tube through the femoral artery to transmit the blocker;
(2) High safety, the operation is operated by a surgeon who is familiar with the anatomy of the heart, and the operation is performed in the operating room, and the repair can be done directly by extracorporeal circulation in case of accidents, while medical interventions are usually performed in the DSA catheterization room and operated by an internist.
(3) Avoid extracorporeal circulation, no need to split the sternum and place drainage tube after surgery;
(4) Small incision on the chest and inconspicuous scars;
(5) The atrial septal defect can be blocked under the guidance of esophageal ultrasound or subxiphoid four-chamber view, which can clearly show the whole process of blocking without X-ray guidance, avoiding the long time X-ray radiation and the intake of contrast agent.
(6) The blocking process is intuitive and safe, and the path of pushing the sheath to release the blocker is short and the sheath is perpendicular to the atrial septal defect, so the position is accurate and fast, while the catheter intervention requires a turn to reach the atrial septal defect after inserting the delivery device from the inferior vena cava, which can easily stimulate the right atrium and cause arrhythmia;
(7) The incidence of blocker dislodgement is low. The blocker is hard and produces a greater retraction force, which can be more closely stuck to the edge of the atrial septal defect, and the blocker is tested for dislodgement by pushing and pulling vertically back and forth.
(8) The operation time is short, the postoperative recovery is faster than conventional open chest, the postoperative time off the ventilator is short, and the hospital stay is reduced accordingly.
(9) The overall cost of the operation is comparable to that of extracorporeal repair, and cheaper than that of medical interventional blocking.
Complications are mainly intraoperative detachment of the umbrella piece, small amount of pleural effusion, intraoperative transient arrhythmia, etc. Intraoperative detachment of the umbrella piece can be removed and the atrial septal defect repaired under extracorporeal circulation. A small amount of pleural effusion can be thoracentesis or self-absorption.