Huanhuan’s mother recently encountered a problem. One month after the surgery of her child’s ventricular septal defect, she saw the term “residual shunt” on the description of the ultrasound result. With this question, Huanhuan’s mother approached me: “Dr. Li, what exactly is the residual shunt after ventricular septal defect repair? Does it matter? What should I do?” Li Pingyuan, Department of Pediatric Cardiac Surgery, Fu Wai Hospital, Beijing
“Huanhuan’s mother, don’t worry, this is a good question, let me explain it slowly. I hope it will help all parents and patients with similar problems to untie their hearts.”
I. Reasons for the occurrence of residual leak after ventricular septal defect repair.
Ventricular septal defect is a relatively common congenital heart disease. It is also a simple heart disease that can be completely rehabilitated into a normal child through surgical treatment.
Surgical treatment is the primary means of curing the disease, which is performed by stopping the heart under extracorporeal circulation and the cardiac surgeon repairing the ventricular septal defect directly or with patch sutures (as shown in the figure).
The problem of residual shunt after ventricular defect repair occurred some years ago and is one of the most common complications after ventricular septal defect repair. Its occurrence is due to various reasons, such as.
1. sutures are too widely spaced (greater than 3 mm)
2. stitches that are too shallow tearing off during knotting or after cardiac resuscitation
3. incorrectly tied knots, too loose leaving a gap or too tight causing tissue tearing
4, the patch is too small and the larger defect is sutured directly, with too much tension after suturing, causing tearing.
5, direct suturing of larger defects, continuous suturing without pressing the patch well, resulting in “cat’s ear” folds.
6, incorrect transfer stitching.
7.In patients with ventricular septal defect (VSD) combined with double chamber right ventricle and tetralogy of Fallot (TOF), handling of abnormal outflow tract bundles and failure to carefully examine residual leak after surgery.
8. direct suturing of defects formed by distensible tumors, confused by surface notches, without careful exploration of the base and without identifying the true margins (this cause is more common)
9, failure to identify keycords and other small ventricular defects covered by partial flaps.
10: failure to completely reveal the edges of the ventricular septal defect in some specific ventricular defects, such as those combined with tetralogy of Fallot (TOF), when the hypertrophic right ventricular outflow tract is removed free.
11: faulty quality of sutures, which break under pressure.
The above causes are subjective factors of the surgeon: such as surgical skill and knowledge of the disease; and objective factors of the ventricular septal defect itself: such as the type and location of the ventricular septal defect. There are also other factors such as the quality of sutures and left ventricular pressure.
Residual shunt after ventricular septal defect surgery is one of the more common complications after ventricular septal defect repair. Almost all cardiac surgeons have faced it and the mood is practically the same as that of the patient and his family. If a large residual leak occurs, it not only affects the surgical result, but also, due to the serious postoperative adhesions of the pericardium and surrounding tissues, it will cause the patient to develop infective endocarditis, and the risk of arrhythmia at a later stage will increase, and the postoperative residual heart murmur will cause greater psychological pressure and social pressure to the patient and family, and some patients may even develop left heart failure and pulmonary hypertension, and the patient will need a second operation, which likewise adds to the medical It also adds more burden to medical care and doctors. Therefore, it is the common enemy of patients and doctors.
In order to reduce or minimize the occurrence of residual shunts after ventricular septal defect repair, cardiac surgeons have been trying to avoid them since the 1950s and 1960s, when the procedure was first performed. Early methods included: interrupted suturing of the entire septum; repeated left heart exhaustion after surgery to observe the repair for oozing blood; or observation of the repair for oozing blood after the heart resumes beating; or palpation of the right ventricular outflow tract for tremor after atrial suturing; these methods were effective in avoiding the occurrence of larger septal residual shunts, but were clumsy and ineffective for smaller postoperative residual shunts of ventricular septal defects.
In another aspect, engineers and technicians are contributing their wisdom, such as: improving the smoothness and strength of surgical sutures and improving the compliance of patch materials.
Indeed, with the rapid development, maturation, and refinement of medical technology in the last decade, everyone’s efforts have been rewarded to some extent with an increasing decrease in the incidence of residual shunts after ventricular septal defect repair. However, this is not enough, because in the past, the occurrence of residual shunts in ventricular septal defects could only be determined by cardiac ultrasound one or more days after surgery. By the time a residual shunt is detected at that time, the patient will need a second open-heart surgery to further eliminate the residual shunt. Another question is, even if you have a second open-heart surgery, can you guarantee that the residual shunt will not occur again?
How can you identify and eliminate residual shunts in a timely and effective manner during the first surgery? This has been the direction that cardiac surgeons and related technicians have been working on. It was not until the emergence of the nemesis of residual shunts in ventricular septal defects more than 10 years ago that surgeons had a big weapon: intraoperative esophageal ultrasound.
With the widespread use of intraoperative esophageal ultrasound, the technology has now made it routine to examine in the operating room after surgical treatment of precardiac disease, thus reducing the complication of residual shunt of ventricular septal defect to a minimum, and all to a very minor degree, so no one has to worry too much.
II. Principles of management of residual leak after ventricular septal defect repair.
More than ten years ago, due to the widespread use of esophageal ultrasound in the operation, after the operation, Fu Wai Hospital must routinely perform esophageal ultrasound examination, which can generally determine immediately whether there is residual shunt or not, and if there is a large residual shunt (>5mm), the doctor will turn the machine twice and re-treat it accordingly. Therefore, in general, patients with ventricular septal defect repair after surgery at Fu Wai Hospital have to pass the first hurdle in the operating room after surgery: esophageal ultrasonography. Esophageal ultrasonography is like a mandatory exam for surgeons, if a large residual shunt is found, sorry, dear Dr. Li, you failed the exam, you need to repair it again and have to retake the exam until you succeed. Now we cardiac surgeons in front of the esophageal ultrasound examination, the feeling is both eager, looking forward to and like the fear of elementary school students before the exam, afraid of failing the exam and bringing unnecessary damage to the patient. If there are no major problems, only then can the procedure be finished and sent back to the recovery room. This significantly reduces the incidence of ventricular septal defect residual shunt after surgery.
If there is a description of residual shunt on ultrasound review after ventricular defect repair, there are two possibilities. One may be caused by a broken suture or suture tear due to suture quality problems, and we all have the experience of sutures cutting our hands when sewing clothes, right? Think about it, skin is such a tough tissue that sometimes sutures can cut it, let alone myocardial tissue. So sometimes when the myocardial tissue is not strong enough, or when an inch of strength causes the sutures to break or tear off, it may cause some of the myocardial tissue to cut and create residual shunts for dozens of hours after surgery.
Another possibility is caused by high left ventricular pressure and rapid blood flow impacting the patch and passing through the patch gaps. Blood is a flowing fluid, just like water. Water has no constant potential and flows wherever there is a seam. Blood has the same property, and under strong left ventricular pressure, blood flow sometimes keeps impacting a weak point on the patch, causing the occurrence of residual shunts found tens of hours after surgery. For residual leaks less than 5 mm in diameter, conservative treatment is feasible, because residual leaks can close on their own through the formation of thrombus at the intersection of the patch and the suture at the defect site, the fusion of the tissue around the defect with the patch adhesion, and the endothelial cell coverage. For residual leaks below 5 mm, there is generally no significant hemodynamic significance, and they do not affect the systemic circulatory function or the growth and development of the child, so parents or patients can rest assured that regular follow-up and close observation are sufficient.
If, during the follow-up, the child develops more serious clinical symptoms, such as severe hemoglobinuria, anemia, or subacute bacterial endocarditis, and if there is no significant improvement with conservative treatment, only then should the child be considered for another surgery or interventional repair as soon as possible.
If the residual shunt of the ventricular septal defect is further enlarged due to suture avulsion, greater than 5 mm, and causes hemodynamic effects, and the patient develops corresponding clinical symptoms, secondary surgical treatment should be considered.
Third, the more special case, how to deal with multiple ventricular septal defects
Multiple ventricular septal defects due to their special characteristics, such as Swiss cheese-like defects. A ventricular septal defect, no matter how you repair it, may not completely eliminate the residual septal shunt, and in this extreme case, esophageal ultrasound is just as powerful. It can show that if the residual shunt is not large, say less than 5 mm, it can suggest to the attending surgeon that the outcome is satisfactory, and that too many surgical maneuvers and too long extracorporeal circulation times in the complete pursuit of no septal residual shunt may in turn serve to injure the patient as a side effect. The attending surgeon is reminded to stop at the right time. The small residual ventricular septal defect can wait until the child grows up and be eliminated by interventional sealing without the need for secondary surgery.
After listening to my words, Huanhuan’s mother breathed a long sigh of relief and said with a smile, “Now I can rest assured, so director Li, do you think I understand this right: because of the limitations of medical technology some years ago, this kind of condition happens a lot, but with the development and maturity of surgery techniques for precardiac disease now it happens very little, especially with the intraoperative application of esophageal ultrasound, the incidence is significantly reduced, especially The best specialized hospitals in the country for the treatment of precocious heart disease is even less. If the residual shunt described on the ultrasound is less than 5 mm, you do not have to worry about it, it does not affect the systemic blood circulation and will not affect the child’s development, but the child should be reviewed regularly; if it is greater than 5 mm, there is no need to worry about it, according to the specific circumstances of the child (clinical symptoms and signs) to let the doctor see, if there are no clinical symptoms generally will not affect anything, do not need to deal with. Some residual shunts can be observed, and when the child is older, they can be eliminated through interventional blocking, and the incidence of secondary surgery is very low.” Looking at the relieved look on Huanhuan’s mother’s face, I happily said to her, “Yes, you understood it right!”
In recent years, the development of cardiac surgery technology and the increasing safety of direct intracardiac surgery under extracorporeal circulation, as well as the increasing skill and improvement of surgeons, especially the emergence of intraoperative esophageal ultrasound as a diagnostic tool, have reduced this complication to a minimum. Therefore, parents and friends do not need to worry, put down the burden, take good care of their children and do regular review, and finally wish the child (person) a speedy recovery!
This article is published with the authorization of Dr. Li Pingyuan.