Outcomes of the Arterial Switch Operation in Children Less Than 2.5 Kilograms

Native Bicuspid Pulmonary Valve in D-Loop Transposition of the Great Arteries: Outcomes of the Neo-Aortic Valve Function and Root Dilation After Arterial Switch Operation

Background Neo-aortic root dilation and neo-aortic regurgitation (AR) are common after arterial switch operation for D-loop transposition of the great arteries. We sought to evaluate these outcomes in patients with bicuspid native pulmonary valve (BNPV). Methods and Results A retrospective analysis of patients with transposition of the great arteries undergoing arterial switch operation at Boston Children's Hospital from 1989 to 2018 matched BNPV patients 1:3 with patients with tricuspid native pulmonary valve by year of arterial switch operation. Kaplan-Meier analyses with log-rank test compared groups for time to first neo-aortic valve reoperation, occurrence of ≥moderate AR, and neo-aortic root dilation (root z score ≥4). A total of 83 patients with BNPV were matched with 217 patients with tricuspid native pulmonary valve. Patients with BNPV more often had ventricular septal defects (73% versus 43%; P<0.001). Hospital length of stay (11 versus 10 days) and 30-day surgical mortality (3.6% versus 2.8%) were similar. During median 11 years follow-up, neo-aortic valve reoperation occurred in 4 patients with BNPV (6.0%) versus 6 patients with tricuspid native pulmonary valve (2.8%), with no significant difference in time to reoperation. More BNPV had AR at discharge (4.9% versus 0%; P=0.014) and during follow-up (13.4% versus 4.3%; hazard ratio [HR], 3.9; P=0.004), with shorter time to first occurrence of AR; this remained significant after adjusting for ventricular septal defects. Similarly, neo-aortic root dilation was more common in BNPV (45% versus 38%; HR, 1.64; P=0.026) with shorter time to first occurrence. Conclusions While patients with BNPV have similar short-term arterial switch operation outcomes, AR and neo-aortic root dilation occur more frequently and earlier compared with patients with tricuspid native pulmonary valve. Further long-term studies are needed to determine whether this results in greater need for neo-aortic valve reoperation.

Long-term outcomes of the arterial switch operation

OBJECTIVES

The arterial switch operation (ASO) has excellent early outcomes in the modern era. We sought to determine the long-term outcomes in patients who underwent an ASO at a single institution.

METHODS

Patients who underwent an ASO between 1983 and 2015 were identified from the hospital database and retrospectively reviewed using hospital records.

RESULTS

From 1983 to 2015, 844 patients with a biventricular circulation underwent an ASO. There were 28 (3.3%, 28/844) early deaths. Follow-up was available for 94% (729/774) of local patients after hospital discharge. Median follow-up was 15 years (interquartile range, 8-20 years). There were 187 (26%, 187/729) patients with more than 20 years of follow-up and 95 (13%, 95/729) patients with more than 25 years of follow-up. Overall survival was 95% (95% confidence interval [CI], 94%-97%) at 10 and 25 years after the ASO. At 25 years after ASO, freedom from overall reintervention was 77% (95% CI, 73%-81%), freedom from reoperation on the neoaortic root or neoaortic valve was 92% (95% CI, 88%-95%), and freedom from coronary reoperation was 99% (95% CI, 98%-99.7%). Left ventricular (LV) systolic function was normal in 595 of 609 (98%) of patients who had LV function quantified at latest follow-up. Of the 95 patients with more than 25 years of follow-up after ASO, 6 (6.3%) had at least moderate neoaortic valve regurgitation (AR) and 8 (8.4%) had undergone replacement of the neoaortic valve.

CONCLUSIONS

Overall, survivors of ASO have excellent late survival and normal LV systolic function into adult life. However, AR and reoperation on the neoaortic valve remains an issue for older patients.

Comparison of management strategies for neonates with symptomatic tetralogy of Fallot and weight <2.5 kg

OBJECTIVE

To compare management strategies for neonates <2.5 kg with tetralogy of Fallot and symptomatic cyanosis who either undergo staged repair (SR) (initial palliation followed by later complete repair) or primary repair (PR).

METHODS

Consecutive neonates with tetralogy of Fallot and symptomatic cyanosis weighing <2.5 kg at initial intervention and between 2005 and 2017 were retrospectively reviewed from the Congenital Cardiac Research Collaborative. Primary outcome was mortality and secondary outcomes included component (eg, initial palliation, complete repair, or primary repair) and cumulative (SR: initial palliation followed by later complete repair) hospital and intensive care unit lengths of stay, durations of ventilation, inotrope use, cardiopulmonary bypass time, procedural complications, and reintervention. Outcomes were compared with propensity score adjustments with PR as the reference group.

RESULTS

The cohort included 76 SR (initial palliation: 53 surgical and 23 transcatheter) and 44 PR patients. The observed risk of overall mortality was similar between SR and PR groups (15.8% vs 18.2%: P = .735). The adjusted hazard of mortality remained similar between groups overall (hazard ratio, 0.59; 95% confidence interval, 0.26-1.36; P = .214), as well as during short-term (<4 months: hazard ratio, 0.37; 95% confidence interval, 0.13-1.09; P = .071) and midterm (>4 months: hazard ratio, 1.32; 95% confidence interval, 0.30-5.79; P = .717) follow-up. Reintervention in the first 18 months was common in both groups (53.2% vs 48.4%; hazard ratio, 1.69; 95% confidence interval, 0.96-2.28; P = .072). Adjusted procedural complications and neonatal morbidity burden were overall lower in the SR group. Cumulative secondary outcome burdens largely favored the PR group.

CONCLUSIONS

In this study comparing SR and PR treatment strategies for neonates with tetralogy of Fallot and symptomatic cyanosis and weight <2.5 kg, mortality and reintervention burden was highly independent of treatment strategy. Other potential advantages were observed with each approach.

Management of 760-g Extremely Premature Infant With Dextro-Transposition of the Great Arteries

Extremely low birth weight neonates with complex congenital heart disease have increased mortality risk. Multi-organ dysfunction, pulmonary disease, fluctuating pulmonary vascular resistance, and complex cardiovascular anatomy create a challenge for effective management. We present the case of a 760-g neonate with dextro-transposition of the great arteries, ventricular septal defect, patent ductus arteriosus, and single coronary artery with proximal intramural segment of the right coronary artery branch. We describe features of preoperative care, surgical intervention, and postoperative course that enabled this infant to survive.

Preoperative simulation for complex transposition of great arteries using a three-dimensional model

We utilised a cast preoperatively prepared on the basis of the patient's computed tomography data to clarify unusual orientation of the great arteries (transposition of great arteries, coarctation of the aorta, and abnormally branching central pulmonary arteries) in a 2.2-kg neonate. The three-dimensional model was very useful for designing the surgical procedure - being easy to handle for real and precise simulation of the reparative manoeuvres.

Twenty-Three-Year Experience With the Arterial Switch Operation: Expectations and Long-Term Outcomes

We aimed to describe the short- and long-term outcomes of patients after an arterial switch operation (ASO) at a single institution during a 23-year period. A retrospective chart review of all patients <18 months of age who underwent an ASO between January 1995 and March 2018 at Texas Children's Hospital, Houston, TX was performed. Primary endpoints include mortality and reintervention. Perioperative mortality was defined as mortality occurring in-hospital and/or <30 days after surgery. Survival and freedom-from-reintervention were analyzed using Kaplan-Meier method, log-rank tests, and Cox regression models. The cohort included 394 patients. Diagnoses included 204 patients (52%) with intact ventricular septum, 137 (35%) with a ventricular septal defect, 17 (4%) with a ventricular septal defect and left ventricular outflow tract obstruction (LVOTO), and 36 (9%) with Taussig-Bing anomaly. Median age at surgery was 8 days (range: 1 day to 17 months) and median weight was 3.4 (range: 0.8-12.0) kg. Overall perioperative mortality was 1.3% (n = 5), 0.3% (n = 1) since 1999. Overall survival at 5, 10, and 15 years was 98.2%, 97.8%, and 97.8%, respectively. Perioperative morality was associated with prematurity (P = 0.012), <2.5 kg (P< 0.001), and longer circulatory arrest (P = 0.024) after univariate analysis. Reintervention was associated with a longer cross-clamp time (P < 0.001), <2.5 kg (P = 0.009), LVOTO resection (P = 0.047), and genetic syndrome (P= 0.011) after multivariable analysis. Current ASO expectations should include a perioperative mortality risk of <1% and good long-term survival. Reinterventions are more frequent in patients <2.5 kg, concomitant LVOTO resection, a genetic syndrome, and longer cross-clamp time.

Association Between Variation in Preoperative Care Before Arterial Switch Operation and Outcomes in Patients With Transposition of the Great Arteries

BACKGROUND

The arterial switch operation (ASO) is the gold standard operative correction of neonates with transposition of the great arteries and intact ventricular septum, with excellent operative survival. The associations between patient and surgeon characteristics and outcomes are well understood, but the associations between variation in preoperative care and outcomes are less well studied.

METHODS

A multicenter retrospective cohort study of infants undergoing neonatal ASO between January 2010 and September 2015 at hospitals contributing data to the Pediatric Health Information Systems database was performed. The association between preoperative care (timing of ASO, preoperative use of balloon atrial septostomy, prostaglandin infusion, mechanical ventilation, and vasoactive agents) and operative outcomes (mortality, length of stay, and cost) was studied with multivariable mixed-effects models.

RESULTS

Over the study period, 2159 neonates at 40 hospitals were evaluated. Perioperative mortality was 2.8%. Between hospitals, the use of adjuvant therapies and timing of ASO varied broadly. At the subject level, older age at ASO was associated with higher mortality risk (age >6 days: odds ratio, 1.90; 95% CI, 1.11-3.26; P=0.02), cost, and length of stay. Receipt of a balloon atrial septostomy was associated with lower mortality risk (odds ratio, 0.32; 95% CI, 0.17-0.59; P<0.001), cost, and length of stay. Later hospital median age at ASO was associated with higher odds of mortality (odds ratio, 1.15 per day; 95% CI, 1.02-1.29; P=0.03), longer length of stay ( P<0.004), and higher cost ( P<0.001). Other hospital factors were not independently associated with the outcomes of interest.

CONCLUSIONS

There was significant variation in preoperative care between hospitals. Some potentially modifiable aspects of perioperative care (timing of ASO and septostomy) were significantly associated with mortality, length of stay, and cost. Further research on the perioperative care of neonates is necessary to determine whether modifying practice on the basis of the observed associations translates into improved outcomes.

Pregnancy Outcomes in Women After the Arterial Switch Operation

BACKGROUND

Pregnancy outcomes after the arterial switch operation (ASO) are rare. We sought to determine outcomes of ASO survivors who underwent pregnancy.

METHODS

Female patients who had an ASO and underwent pregnancy were identified from the congenital heart disease pregnancy clinic at The Royal Melbourne Hospital. All follow-up data were collected retrospectively by medical record review.

RESULTS

Eleven (11) women were identified as having undergone medical care during pregnancy, from the adult congenital database, at The Royal Melbourne Hospital. There were 17 successful pregnancies, and nine women have been followed post pregnancy. Of the 17 successful deliveries, eight were delivered by Caesarean section, seven were vaginal deliveries and two were instrumented vaginal deliveries. Of the eight Caesarean sections, five were emergency and three were elective. The indications for emergency Caesarean section were obstructed labour (n = 2), abnormal cardiotocography (n = 1), obstructed labour and abnormal cardiotocography (n = 1) and congestive cardiac failure (n = 1). There was one neonatal complication (respiratory distress requiring intubation) in a child born at 31 weeks. There were maternal obstetric complications in 10 patients. There were two maternal cardiac complications during pregnancy (heart failure and rapid atrial fibrillation/flutter). There was no change in left ventricular function post-pregnancy. There was progression of severity of neo-aortic valve regurgitation in two patients post pregnancy (trivial to mild and moderate-severe to severe respectively).

CONCLUSION

Pregnancy post ASO appears to be safe in the majority of women. Maternal cardiac complications are uncommon in patients without residual significant haemodynamic lesions, although maternal obstetric complications may be common.

Outcomes of the Arterial Switch Operation in ≤2.5-kg Neonates

Although low birth weight is a known risk factor for mortality in congenital heart lesions and may consequently delay surgical repair, outcomes in low-weight neonates undergoing the arterial switch operation (ASO) have not been well described. Our objective was to assess the safety of this procedure in infants weighing ≤2.5 kg at the time of surgery. We retrospectively analyzed outcomes for all neonates undergoing the ASO at our institution from 2005 to 2015. Our primary outcome of interest was major morbidity or operative mortality, assessed as a composite outcome. From 2005 to 2015, 217 neonates underwent the ASO, with 31 (14%) weighing ≤2.5 kg at the date of surgery, and 8 weighing <2.0 kg. Neonates weighing ≤2.5 kg were more likely to be premature than those weighing >2.5 kg, but there was no difference in the age at operation between these groups. Overall, 32 infants experienced a major morbidity or mortality, including 37.5% (n = 3) weighing <2.0 kg, 8.7% (n = 2) weighing 2.0-2.5 kg, and 14.5% (n = 7) weighing >2.5 kg (P = 0.141). One infant weighing <2.0 kg (1.1 kg) and 4 infants weighing >2.5 kg died. In multivariable models, odds of major morbidity or mortality were significantly higher for infants weighing <2 kg compared with infants weighing >2.5 kg (odds ratio 3.93, 95% confidence interval 1.04-14.85, P = 0.044), but there was no difference between infants weighing 2.0-2.5 kg and those weighing >2.5 kg (P = 0.225). The ASO can be performed safely in 2.0- to 2.5-kg neonates and yields results comparable with higher weight infants. Imposed delays for corrective surgery may not be necessary for these low-weight infants with transposition of the great arteries.