Mostly Outlet Challenges

Objective: Right ventricular outflow tract (RVOT) obstruction remains a frequent complication after Taussig-Bing anomaly repair. We studied anatomic and operative variables for association with freedom from RVOT reintervention after the arterial switch operation among patients with a Taussig-Bing anomaly.
Methods: Retrospective review identified all patients with a Taussig-Bing anomaly who underwent an arterial switch operation from 1995-2020 at a single institution. We calculated the pulmonary to aortic valve diameter ratio (P/A ratio) and aortic arch Z-scores from echocardiography-derived data. Freedom from RVOT reintervention was modeled as a time-to-event variable. The Kaplan-Meier estimator, log-rank test, and Cox-proportional hazards regression analysis studied factors for association with freedom from RVOT reintervention.
Results: Forty-one patients with Taussig-Bing anomaly underwent arterial switch (median age: 39d). Subaortic resection was performed in 20/41 (48%) patients, arch repair in 24/41 (58%) patients, and LeCompte maneuver in 35/41 (85%) patients. LeCompte maneuver was not performed in 6/41 patients (two with posterior aorta and four with great vessels size discrepancy). At median follow-up of 8 years, there was 93% survival and 69% freedom from RVOT reintervention. At 8 years, risk factors for RVOT reintervention included requirement for arch repair (50% vs 94%, p=0.008), no LeCompte maneuver (28% vs 75%, p=0.05), and lower aortic arch Z-scores (HR 0.5, p=0.03); while P/A ratio was not associated with RVOT reintervention (HR=3.2, p=0.2). At 8 years, freedom from RVOT reintervention was 93% in 16 patients with LeCompte (no arch repair), 59% in 19 patients with arch repair and LeCompte, and 28% in 6 patients with arch repair (no LeCompte) (p=0.02, Figure).
Conclusions: Aortic arch repair in patients with an aortopulmonary relationship unsuitable for a LeCompte maneuver was associated with a high burden of RVOT reinterventions. 

Objective : Tetralogy of Fallot (TOF), pulmonary atresia and major aortopulmonary collaterals (MAPCAs) is a complex congenital heart defect with varied clinical and anatomic findings. For years, our program has recommended early single-staged midline unifocalization at 3 to 6 months of age, in order to maximize the health of the pulmonary microvascular bed. However, many patients are referred beyond 6 months, and it is not clear if outcomes are similar in older infants. Thus, we sought to evaluate surgical outcomes according to age at repair.

Methods : We performed a retrospective chart review to identify patients who underwent unifocalization from age 3 to 12 months. These patients had not undergone prior surgery at our institution or elsewhere and were also not protocoled into early surgery for either aorto-pulmonary window creation, unilateral pulmonary artery (PA) origin from a PDA or hemitruncus. Patients were divided in the following age groups: 3.0-4.9months (group 1), 5.0-5.9months (group 2), 6.0-7.9months (group 3) and 8.0-11.9months (group 4). Competing risk regression analyses were performed.

Results : We included 220 patients that were operated from 2001 to 2020. The 4 surgical groups were: 61 patients in group 1, 56 patients in group 2, 56 patients in group 3 and 47 patients in group 4. Baseline characteristics, such as number of MAPCAs (median n=4), genetic syndrome including 22q11 deletion (45% to 52%), preoperative respiratory support (12% to 23%), most often oxygen delivery via nasal cannula, were not different amongst the 4 age groups. Overall, single-stage complete TOF repair with bilateral unifocalization, VSD closure, ASD closure and RV-PA conduit placement was achieved at first surgery in 174 (79%) patients and did not differ across age groups (74% to 84%). Airway-related reoperations, such as aortopexy (n=5, 2%) and tracheostomy (n=7, 3%), as well as duration of post-operative mechanical ventilation (median 4 days) were similar. Early mortality was 4% (n=9) for the entire cohort. At one year following first surgery, 90% of the entire cohort was fully septated. Group 4 was significantly less likely to undergo any catheter-associated PA reinterventions following complete repair (HR 0.44, 95% CI 0.21-0.92, p value 0.028) or surgical PA reinterventions (HR 0.12, 95% CI 0.02-0.95, p value 0.044).

Conclusions : Given the excellent outcomes across all age groups, surgical timing for single-stage unifocalization for TOF-PA-MAPCA should be dictated by clinical and anatomic details, with potential advantage in clinically appropriate older patients who appear to be at a lower probability of PA reinterventions following full septation. Airway complications were not greater in younger infants. Lastly, there was no difference in the likelihood of a single-stage complete repair across the different groups. 

Objective: Transposition of the great arteries (TGA) or TGA-type double outlet right ventricle with left ventricular outlet tract (LVOT) obstruction involving the antero-posterior position of the great arteries are reportedly preferred indications for the half-turned truncal switch operation (HTTSO). We successfully applied the HTTSO with modification for this spectrum with side-by-side arrangement of the great arteries, and provided excellent outflow tracts of the right and left ventricles. In this modification, the detached pulmonary valve was implanted to the right ventricular outflow tract (RVOT) portion. The defect of the aortic valve at the RV inflow portion was filled with a flipped-up infundibular (IF) septal flap.
Case summary: A 2-year-10-month-old boy weighing 13.8 kg was diagnosed with posterior TGA with LVOT obstruction. The great arteries were arranged side-by-side with the aorta on the right. The pulmonary valve had bicuspid valvular stenosis accompanied with IF stenosis, and the ventricular septal defect (VSD) was located in the remote position. The aorta was transected about 10mm above the sino-tubular junction. The pulmonary trunk was transected just below the bifurcation. Both coronary arterial cuffs were excised. The truncal block involving both semilunar valves was harvested en bloc. Both ends of the IF were resected longitudinally. The VSD was closed using a curved-designed ePTFE patch to prevent residual LVOT obstruction. The aortic valve was half-turned horizontally, and anastomosed to the LVOT orifice. The superior margin of the VSD patch was anastomosed to the IF septum. Both coronary cuffs were anastomosed to the corresponding aortic wall defects. The IF septal flap was flipped up and anastomosed to the aortic valve defect at the RV inflow portion. The ascending aorta was reconstructed by end-to-end anastomosis. The pulmonary valve obtained an adequate size by commissurotomy. The pulmonary valve was anastomosed to newly created orifice at the RVOT. The anterior wall of the neo-RVOT was augmented with the ePTFE patch. The distal stump of the pulmonary trunk was anastomosed directly to the pulmonary bifurcation. Postoperative CT showed excellent outflow tracts of the right and left ventricles.
Conclusion: The neo-RVOT orifice is located just in front of the LVOT in the common antero-posterior great artery arrangement of TGA; however, the aortic valvular defect is located at the inflow portion in a side-by-side great artery arrangement. Hence, the neo-RVOT orifice was created at the outflow portion instead of the inflow portion to prevent turbulent flow in the right ventricle. The aortic valvular defect at the RV inflow portion was closed with an autologous pedicle IF muscle flap. This modification of HTTSO is an useful technique for TGA with a side-by-side great artery arrangement, producing excellent outflow tracts of right and left ventricles. 

Objective
Arterial switch operation (ASO) with aortic arch reconstruction for transposition complex associated with aortic arch obstruction remains a challenging procedure. Early mortality rate is not negligible, and late reinterventions are not uncommon after ASO with aortic arch repair. The aim of the study was to investigate midterm outcomes and factors associated with reinterventions in patients undergoing ASO and aortic arch repair.

Methods
From 2004 to 2020, 51 patients who underwent ASO and aortic arch reconstruction were included in this study. Forty-nine patients (96.1%) underwent repair primarily, and two patients (3.9%) underwent staged repair. Median follow-up duration was 59 months. Significant pulmonary stenosis (PS) was defined as peak velocity greater than 3 m/s on echocardiography.

Results
Twenty-eight patients (54.9%) had Taussig-Bing anomaly, and 23 patients (45.1%) had transposition of the great arteries with ventricular septal defect. Forty-three patients (84.3%) had coarctation of the aorta, and eight (15.7%) had interrupted aortic arch. The median age and body weight at repair was 9 days (range 4–180 days) and 3.1 kg (2.3–5.3 kg), respectively. There were five early deaths (9.8%). Late death occurred in two patients. One patient required a heart transplantation. Transplant-free survival was 86, 86 and 83% at 1, 5 and 10 years after repair, respectively. Nineteen reinterventions (13 reoperations and 6 catheter interventions) were required in 10 patients. Reintervention free survival was 74%, 66% and 63% 1, 5, and 10 years after surgery, respectively. Significant PS free survival 80%, 76% and 68% 1, 5, and 10 years after surgery, respectively (Figure). In univariable analysis, ratio of the diameters of the main pulmonary artery to the ascending aorta (great artery ratio) was associated with any reinterventions (HR, 10.5; P=.007) and right-sided reinterventions (HR, 16.1; P=.002). Aortic annulus z-score as neo-pulmonary was associated with significant PS (HR, 0.382; P=.049).

Conclusions
The overall mortality rate after ASO and aortic arch reconstruction is still considerable. Right-sided reintervention was not uncommon after ASO and aortic arch reconstruction. Ratio between the diameters of both great arteries was associated with right-sided reintervention after ASO and aortic arch reconstruction. Smaller aortic annulus z-score as neo-pulmonary was associated with the development of significant PS.