In 1987, Pigott et al. were the first to report the successful first-stage correction of D-TGA with aortic arch obstruction. In 1991, Serraf et al. proposed stage I surgery for Taussig-Bing combined with aortic arch malformation, and since the end of last century, stage I aortic switch and aortic arch malformation correction has gradually been widely adopted in cardiac centers worldwide; in recent years, the early complication rate and mortality rate of stage I surgery have improved significantly, but how to improve early and long-term survival and reduce However, the challenge remains to improve early and long-term survival and reduce long-term reintervention and surgery rates [1-5]. In Shanghai Children’s Medical Center, 26 consecutive cases of complete aortic malformation with aortic arch malformation or Taussig-Bing malformation were treated with stage I surgery between January 2000 and December 2008, and were followed up with good early and intermediate results. The purpose of this article is to review the experience and analyze how to meet the challenges.
1. Clinical data and methods
1.1 General data: 26 small infants with complete aortic misalignment or Taussig-Bing malformation with aortic arch obstruction underwent stage I artery switch operation (ASO) and correction of aortic arch malformation, including 13 cases of complete aortic misalignment (11 cases of TGA/VSD, 11 cases of TGA/IVS2) and 13 cases of Taussig-Bing malformation. Among them, there were 13 cases of complete aortic dislocation (TGA/VSD 11, TGA/IVS2) and 13 cases of Taussig-Bing; 7 cases of interrupted aortic arch (IAA) (type A), 19 cases of CoA (8 cases of pre-catheter type, 3 cases with aortic arch dysplasia, and 8 cases of isthmus COA), and 6 cases with coronary artery anomalies. The average age at surgery was 28 days ± 35 days (5 to 90 days) in the remaining 23 cases, except for 3 cases of Taussig-Bing malformation, which were 9 months, 7 months, and 6 months, respectively, accounting for 62% of cases <2 months, and about 80% of cases <2 months in the last 3 years; the average weight at surgery was 4.19 kg ± 1.15 kg (3.2 kg to 6.3 kg). 3.2kg~6.3kg). Two patients with IAA had preoperative prostaglandin E to maintain arterial catheter development; 3 of the 26 cases required preoperative ventilator assistance; 5 cases had preoperative pneumonia and heart failure.
1.2 Surgical approach and postoperative management The surgical approach was all through a median sternal incision, with routine use of blood-containing cold myocardial protective fluid and hybrid ultrafiltration techniques. The treatment of aortic arch deformity was performed under limited deep hypothermic stop circulation (DHCA) or deep hypothermic low flow (DHlf), with PH homeostasis for deep hypothermia (cooling to anal temperature of 18 degrees Celsius) and control of deep hypothermic low flow at 50 ml/min/Kg, and local cerebral tissue perfusion (perfusion flow: 35-45 ml/min/kg) in the last 3 years. The average extracorporeal circulation diversion time was 173.11min±109min (109min~447min), the average aortic block time was 66min±32.98min (63min~178min), and the stopping circulation time was 25min~47min (34.5min±10.5min).
The arch was enlarged or reconstructed using direct anastomosis of the own tissue, and the patch was enlarged and shaped in 62% of cases with arch dysplasia. IAA was reconstructed with enlarged end-lateral anastomosis at both ends of the interruption, and some patients were treated with enlarged arch shaping using a patch; COA was treated with COA segment resection and enlarged end-lateral anastomosis.
Those with coronary artery anomalies were treated with modified coronary artery grafting methods during the major artery conversion surgery.
Treatment of the two aorta conversions: anterior-posterior transposition is routinely performed when the two aorta are reconnected and anastomosed, but anterior-posterior transposition of the aorta is not necessary in Taussig-Bing anomalies where the two aorta are in lateral-lateral position (50%).
In cases where the root diameter of the new aorta is significantly larger than the distal aortic diameter by more than two times (23%), the diameter of the root is first reduced at the posterior wall without a valve junction, and then the aorta is connected by proximal and distal anastomosis; when Taussig-Bing malformation is repaired and the new common pulmonary artery is connected, an incision is first made at the distal transection of the common pulmonary artery toward the lower edge of the right pulmonary artery, and the left side of this transection is closed with a suture. The suture is closed, and then the root of the new pulmonary artery is repaired with its own pericardial patch and then the common pulmonary artery is reconstructed to the right of the new aorta to avoid compression of the grafted coronary artery.
Ventricular septal defect (VSD) repair route: in Taussig-Bing malformation and D-TGA with subaortic VSD (65%), the aortic pathway was chosen to repair the VSD; the membranous VSD (35%) was repaired via the right atrium.
Postoperative monitoring and management: Rational use of positive inotropic drugs (dobutamine combined with milrinone was preferred), rational ventilator-assisted mode, prevention and control of pulmonary hypertension crisis, and close detection and assessment of organ function (e.g., blood gas analysis, serum lactate, mixed venous oxygen saturation and troponin) were emphasized.
13 Follow-up data: clinical findings from follow-up visit responses and outpatient review, cardiac ultrasonography or MRI, cardiac catheterization if necessary, and the presence of peak systolic flow velocity ≥3 m/s on cardiac ultrasonography suggesting the presence of stenosis.
1.4 Statistical analysis: SPSS15.0 statistical software was used, and data were expressed as mean ± standard deviation (x ± SD). X2 test was used for single-factor analysis and logistic multiple linear regression analysis for multi-factor analysis regarding early complications and risk factors for death; Kaplan-Meier survival analysis was used for postoperative survival.
2. Results
There were 3 surgical in-hospital deaths (11.5%) and no surgical in-hospital deaths in the last 3 years; the causes of death were not related to coronary artery grafts. 1 patient with Taussig-Bing with aortic arch dysplasia and coronary artery malformation, the oldest of whom was 9 months old, died 5 hours after surgery due to third-degree atrioventricular block, severe hypovolemic syndrome, and pulmonary hypertension crisis; another patient with TGA/ASD/ Another patient with TGA/ASD/VSD/COA had severe distal obstruction of the ascending aorta after surgery and was re-expanded under extracorporeal circulation and died after surgery due to severe heart failure and low cardiac output.
The average duration of postoperative airway intubation was 102 hours, except for 2 cases who were left in place for 313 and 234 hours due to pneumonia and lack of active substance on the alveolar surface, respectively, and an average of 8 days in the intensive care unit.
There were 2 cases of early postoperative survivors with supra-aortic pressure gradient >30 mmHg, 1 case with supra-pulmonary pressure gradient >30 mmHg, and 2 cases with mild aortic regurgitation. In the early postoperative period, there were 4 cases of severe low cardiac output syndrome, 4 cases of pulmonary hypertension crisis, 3 cases of III degree AV block (2 cases recovered and 1 case died), 2 cases of multiple organ function injury, and 1 case of hemorrhage, and the number of early postoperative complications decreased significantly in the past 3 years (50% to 24%); 4 cases required delayed chest closure after surgery.
The univariate analysis associated with the risk of early postoperative death or complications was associated with those with the type of coronary artery anomaly (p = 0.04), but the multifactorial analysis treated no correlation, and the multifactorial analysis showed that it was associated with age at surgery, pulmonary hypertension, preoperative FS, time of aortic block, and postoperative serum lactate level (1 of the 2 cases with p30 mmHg had no significant progression, while 1 case had pressure at one year postoperatively The differential pressure improved after percutaneous balloon dilatation, but restenosis occurred nearly four years after surgery, and surgical expansion was performed to relieve supra-aortic valve obstruction.
One case had a pressure gradient >30 mmHg in the early postoperative period on the pulmonary valve and developed progressive obstruction with a pressure gradient of 85 mmHg, which was relieved by surgery after the effect of percutaneous balloon dilation was not obvious nearly 5 years after surgery.
Two cases with mild aortic regurgitation showed no progression during the follow-up period. The percentage of those who did not require interventional intervention or surgery at 1 and 5 years after surgery was 91.4% and 87%, respectively.
3. Discussion
3.1 One-stage or staged surgery?
The choice of staged or phased surgery for complete aortic dislocation or Taussig-Bing malformation with aortic arch deformity remains controversial. The overall mortality rate of staged surgery reported in the 1990s was 31-64%, and the overall survival rate of one-stage surgical correction was 80-90% [1-5]. Recently, Hirata.Y et al. reported that the in-hospital mortality rate was only 1.9% in patients with D-TGA or Taussig-Bing deformity with COA after one-stage orthopedic surgery, and there was one death during the follow-up period [6-10].
The survival rate of patients with D-TGA or Taussig-Bing malformation combined with aortic arch malformation treated in one consecutive stage during the last 9 years at Shanghai Children’s Medical Center was 88.5%, with no in-hospital mortality in the last 3 years and no death in the early and mid-term follow-up of survivors.
One-stage surgery avoids multiple surgeries and the development of pulmonary vascular disease, improves the overall survival rate and reduces the financial burden on the patient’s family. Regarding the best selection strategy for this group of complex surgeries, Shanghai Children’s Medical Center recommends that a cardiac center with a certain level of experience and sophistication needs to thoroughly evaluate the patient’s condition before surgery and prefers one-stage surgery for correction, and that one-stage surgery is not appropriate if there are serious extracardiac complications such as necrotizing microsomia and subretinal hemorrhage before surgery.
3.2 Aortic arch malformation management countermeasures
In this group of patients undergoing stage I aortic switch and aortic arch malformation management, the technical method of extracorporeal circulation and the design and selection of materials for arch treatment directly affect the surgical outcome and long-term survival [11-12]. In recent years, Shanghai Children’s Medical Center has adopted a modified technique of deep hypothermia, i.e., deep hypothermia with low flow and local cerebral perfusion, as well as a design and approach focusing on aortic arch reconstruction or enlargement and shaping, with no significant residual arch obstruction and no hospital death in the past three years. In the early years, there was a case in which the aortic arch was enlarged without appropriate patching, and after the operation, there was residual obstruction of the aortic arch, severe low cardiac output, and the extracorporeal circulation could not be evacuated, and then appropriate enlargement of the aortic arch was given again, but eventually died due to severe heart failure.
In this group of patients, the experience of Shanghai Children’s Medical Center is as follows: in addition to limited COA, extracorporeal circulation assisted by deep hypothermia with low flow and local cerebral perfusion should be used, and if necessary, the circulation should be stopped if the local treatment is extensive; when combined with IAA or aortic arch severe dysplasia type COA, before establishing extracorporeal circulation to divert the flow, use Double arterial perfusion (ascending aorta and common pulmonary artery are cannulated separately) to ensure effective blood supply to the lower body, and at the same time, the blood flow of left and right pulmonary arteries should be controlled separately before the transfer to avoid the occurrence of perfused lung and severe hypoperfusion of the body circulation; when reconstructing or enlarging the arch treatment, own material and direct anastomosis technique are preferred, and if the interruption of IAA is far apart or the arch is severely dysplastic, enlarged reconstruction is required.
3.3 Modified technique of aortic conversion
Large artery misalignment or Taussig-Bing malformation with abnormal coronary artery type, which used to be one of the high risk factors for serious complications and death in the early postoperative period after large artery conversion, and in recent years many centers have adopted various coronary graft modification techniques. Now data and reports suggest that the abnormal coronary artery type is not a high risk factor for early death [9-14]. In this group of patients at Shanghai Children’s Medical Center, 23% of the patients had coronary artery anomalies, and some of the patients had their coronary artery grafts replaced by “J” shaped grafts instead of “U” shaped grafts at the root of the new aorta, which is the trapdoor method. The cause of postoperative hospital death in this group at Shanghai Children’s Medical Center was not related to the type of coronary artery, although a single-factor analysis of risk factors for death in this group found coronary artery anomalies to be one of the risk factors (P=0.04), but a multifactor analysis suggested that the type of coronary artery anomaly was not related to the early risk (P=0.04). type did not correlate with early risk (P>0.05), and no survivors were found to have significant coronary ischemia manifestations during the follow-up period.
The main cause of distant reintervention or reoperation for aortic switch is supra-aortic stenosis or pulmonary root stenosis, and there are long-term follow-up studies reporting a 10-20% restenosis incidence, especially in patients with Taussig-Bing malformation where there is a significant size difference between the two aortic diameters, when combined with IAA or severe When combined with IAA or severe COA malformation, the original aortic root is relatively small and prone to postoperative restenosis. In Shanghai Children’s Medical Center, the measures to prevent re-infarction after aortic switch are: using various techniques of modified anastomosis of the aortic connection, among which when the two aorta are in lateral lateral position, anterior-posterior transposition of the aorta is not advisable, and a tension-free buttress connection should be given, so that compression of the coronary artery can be avoided at the same time; the cut and size of the patch for repairing the new pulmonary artery root should be appropriate to the size and length of the root and distal connection. Their postoperative data suggest that one of the two early postoperative survivors with supra-aortic pressure gradient >30 mmHg did not progress significantly, while one case with pressure gradient >50 mmHg improved after percutaneous balloon dilatation one year after surgery, but restenosis occurred nearly four years after surgery, and surgical expansion was performed to relieve supra-aortic valve obstruction. The number of patients who did not require intervention or surgery at 1 and 5 years postoperatively was 91.4% and 87%, respectively.
3,4 Timing of surgery
The timing of surgery for stage I correction of D-TGA or Taussig-Bing malformation with aortic arch deformity is suggested by the clinical study data of Shanghai Children’s Medical Center. 60% of their patients had surgery at an early age of less than 2 months, but the mean age was higher than that reported abroad [6-7,15], but about 80% of patients in the last 3 years