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Objectives: Left atrioventricular valve (LAVV) operation following repair of atrioventricular septal defects (AVSD) can be challenging. We sought to describe characteristics and outcomes of patients requiring LAVV operation., Methods: Retrospective review of AVSDs requiring LAVV operation between 2000-2020. Patients who experienced adverse events (AEs; defined as the need for a LAVV reoperation (repair or replacement) or death) were compared to patients without AEs. Freedom from adverse events was displayed using the Kaplan-Meier method. Reoperation and death were characterized in terms of cumulative incidence function, estimated using competing risk models., Results: Of 843 patients with AVSD repaired, 59 (7.3%) required a LAVV operation and 7 (9%) valve replacement. A simple repair (cleft closure and/or annuloplasty) occurred in 26 (48.1%) and complex repair using multiple techniques in 28 (51.8%) cases. Eleven patients (20%) required further LAVV reoperation; 3 replacement of mechanical valve, 6 new valve replacement (2 Melody, 4 Mechanical) and 2 re-repair. The cumulative incidence of freedom from AE was 84.1% (75.0%, 94.2%), 78.3% (68.2%, 90.0%), 73.4% (62.2%, 86.7%), 69.7% (57.5%, 84.7%) at 1, 5, 10 and 15 years respectively. Cox univariable regression showed smaller weight (p=0.027) and early need for LAVV operation (p=0.02) were associated with AEs while cleft closure (p = 0.003) was protective against AEs. The estimated cumulative incidence of reoperation was higher in complex repairs (17.3% (7.8%, 38.7%) vs 0.5% (NA, NA) at 1 year. Greys p = 0.02). In a comparison of eras (2000-2009, 2010- 2020) there was no difference in AE (Greys p = 0.96)., Conclusions: Adverse outcomes following LAVV reoperation remain common. Smaller infants, those requiring earlier reoperation and complex type repairs are at highest risk. Future studies should focus on which high risk LAVVs are more suited to early LAVV replacement., (Copyright © 2024. Published by Elsevier Inc.)

Background: Long-term enlargement of the aortic arch after aortic arch reconstruction in hypoplastic left heart syndrome is not well described., Methods: Aortic arch measurements for 50 patients with hypoplastic left heart syndrome who achieved Fontan completion were converted to Pediatric Heart Network z-scores. Dimensions were assessed using linear mixed models, and differences among time points were evaluated with F-tests. Sub-analysis was conducted comparing Norwood (n = 36) with hybrid (n = 14) strategies., Results: Median time to last imaging was 6.4 (interquartile range, 3.5-11.3) years. Before intervention, the main pulmonary artery was dilated, whereas the ascending aorta, transverse arch, and isthmus were hypoplastic. With aortic arch reconstruction, there were expected increases in all arch z-scores. The aortic arch continued to dilate after aortic arch reconstruction, reaching peak values at 7 months (neo-aortic complex: z = 6.9 [5.6-8.0]) or 12 months after stage I (ascending aorta: z = 6.1 [2.9-8.3]; transverse arch: z = 4.7 [3.0-5.9]). After peak values, there was a gradual decline in z-scores with most components still at least mildly dilated at 16 years (neo-aortic complex: z = 3.2 [3.1-3.9], ascending aorta: z = 3.9 [3.3-4.2]; transverse arch: z = 3.1 [2.5-3.7]) with abrupt caliber change at the isthmus: z = -0.8 (-1.1 to -0.3). Norwood and hybrid strategies showed similar enlargement profiles after 7 months of age., Conclusions: Neo-aortic root and aortic arch in hypoplastic left heart syndrome are enlarged early after aortic arch reconstruction and continue to enlarge out of proportion to normal controls until 12 months of age, with gradual decline in enlargement up to adolescence. Further work should focus on modifiable surgical factors that may prove important to optimize arch growth and geometry., Competing Interests: Conflict of Interest Statement The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest., (Copyright © 2024 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest.

Objective: To compare patient characteristics and overall survival for infants with critical left heart obstruction after hybrid palliation (bilateral pulmonary artery banding with or without ductal stenting) versus nonhybrid management (eg, Norwood, primary transplantation, biventricular repair, or transcatheter/surgical aortic valvotomy)., Methods: From 2005 to 2019, 1045 infants in the Congenital Heart Surgeons' Society critical left heart obstruction cohort underwent interventions across 28 institutions. Using a balancing score propensity analysis, 214 infants who underwent hybrid palliation and 831 infants who underwent nonhybrid management were proportionately matched regarding variables significantly associated with mortality and variables noted to significantly differ between groups. Overall survival between the 2 groups was adjusted by applying balancing scores to nonparametric estimates., Results: Compared with the nonhybrid management group, infants who underwent hybrid palliation had lower birth weight, smaller gestational age, and higher prevalence of in-utero interventions, noncardiac comorbidities, preoperative mechanical ventilation, absent interatrial communication, and moderate or severe mitral valve stenosis (all P values < .03). Unadjusted 12-year survival after hybrid palliation and nonhybrid management, was 55% versus 69%, respectively. After matching, 12-year survival after hybrid palliation versus nonhybrid management was 58% versus 63%, respectively (P = .37). Among matched infants born weighing <2.5 kg, 2-year survival after hybrid palliation versus nonhybrid management was 37% versus 51%, respectively (P = .22)., Conclusions: Infants born with critical left heart obstruction who undergo hybrid palliation have more high-risk characteristics and anatomy versus infants who undergo nonhybrid management. Nonetheless, after adjustment, there was no significant difference in 12-year survival after hybrid palliation versus nonhybrid management. Mortality remains high, and hybrid palliation confers no survival advantage, even for lower-birth-weight infants., (Copyright © 2023 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: To determine patient characteristics and outcomes after Norwood versus comprehensive stage II (COMPSII) for infants with critical left heart obstruction who had prior hybrid palliation (bilateral pulmonary artery banding ± ductal stent)., Methods: From 23 Congenital Heart Surgeons' Society institutions (2005-2020), 138 infants underwent hybrid palliation followed by either Norwood (n = 73, 53%) or COMPSII (n = 65). Baseline characteristics were compared between Norwood and COMPSII groups. Parametric hazard model with competing risk methodology was used to determine risk and factors associated with outcomes of Fontan, transplantation, or death., Results: Infants who underwent Norwood versus COMPSII had a higher prevalence of prematurity (26% vs 14%, P = .08), lower birth weight (median 2.8 vs 3.2 kg, P < .01) and less frequent ductal stenting (37% vs 99%; P < .01). Norwood was performed at a median age of 44 days and median weight of 3.5 kg, versus COMPSII at 162 days and 6.0 kg (both P < .01). Median follow-up was 6.5 years. At 5 years after Norwood and COMPSII, respectively; 50% versus 68% had Fontan (P = .16), 3% versus 5% had transplantation (P = .70), 40% versus 15% died (P = .10), and 7% versus 11% are alive without transition, respectively. For factors associated with either mortality or Fontan, only preoperative mechanical ventilation occurred more frequently in the Norwood group., Conclusions: Higher prevalence of prematurity, lower birth weight, and other patient-related characteristics in the Norwood versus COMPSII groups may influence differences in outcomes that were not statistically significant for this limited risk-adjusted cohort. The clinical decision regarding Norwood versus COMPSII after initial hybrid palliation remains challenging., (Copyright © 2023 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Treatment of tubular hypoplasia of the aortic arch (THAA) associated with aortic coarctation (CoA) remains controversial. We aimed to evaluate growth of unrepaired hypoplastic proximal aortic arches (PAAs) after surgical repair for CoA., Methods: Preoperative and follow-up echocardiographic images of 139 patients who underwent CoA repairs from 2005 to 2012 were reviewed. THAA was defined as PAA z-score <-3 and non-THAA group z-score ≥-3. Reintervention rates due to aortic obstruction were assessed using competing risk models and diameters of the aorta were compared with Mann-Whitney U tests., Results: Fifty patients (36%) had THAA and 89 (64%) had non-THAA. The survival rate was 94% at 10 years. The overall reintervention rate at 10 years was 9% in the THAA group and 16% in the non-THAA group (P = .54). The catheter reintervention rate at ten years was 2% in the THAA group and 16% in the non-THAA group (P = .031). The surgical reintervention rate at ten years was 7% in the THAA group and 0% in the non-THAA group (P = .016). All 4 patients who required surgical reintervention were in the THAA group and 3 patients with PAA obstruction had preoperative PAA z-scores -3.6, -4.2, and -4.3. Follow-up echocardiograms showed PAA catch-up growth in the THAA group compared with the non-THAA group (preoperative z-score of -3.6 vs -2.3, and at 7 years of -1.1 vs -1.2; P < .001)., Conclusions: Unrepaired PAA hypoplasia grows after CoA repair. Reintervention rates were comparable between groups but those with THAA had higher surgical reintervention rates., (Copyright © 2022 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: We hypothesized that preoperative patient characteristics and branch pulmonary artery (PA) size might influence the rate of postoperative branch PA reintervention in patients with transposition of the great arteries who undergo the arterial switch operation (ASO)., Methods: The retrospective single-center study included 262 consecutive (2008-2017) newborns who underwent the ASO. Demographic characteristics, echocardiography, and clinical outcomes were reviewed. Competing risk analysis modeled incidence of branch PA reintervention and cause-specific hazard regression for predictors analyses., Results: Median age and weight were 7 (range, 5-11) days and 3.4 (range, 3.1-3.8) kg, respectively. Various types of early branch PA reinterventions (concomitant revision or reintervention during the intensive care unit stay) were required in 28 (10.7%) patients. These patients had prolonged ventilation (P < .001), intensive care unit duration (P < .001), worse right ventricular function (P = .043), and high in-hospital mortality (P = .010). Branch PA dimensions significantly decreased immediately after ASO compared with baseline measurements. The median follow-up duration was 20.8 (range, 0.9-44.7) months. Branch PA reintervention was common among survivors without early reinterventions (9.4%), and even more frequent among those with early reinterventions (25%). Subsequent reintervention (all catheter-based) was necessary for more than one-third of patients after initial branch PA reintervention. The multivariable analysis showed preoperative dimension of the left PA (hazard ratio, 0.527 [95% CI, 0.337-0.823]; P = .005), and right PA (hazard ratio, 0.503 [95% CI, 0.318-0.796]; P = .003) were independently associated with late branch PA reinterventions., Conclusions: Branch PA reintervention was common and often required surgical or catheter-based reinterventions after ASO. PA branch diameters became significantly smaller after ASO. Smaller preoperative branch PA predicted late branch PA reintervention, indicating a smaller margin of geometrical tolerance to this effect., (Copyright © 2022 The American Association for Thoracic Surgery. All rights reserved.)

Objective: The aim of this systematic review and meta-analysis is to evaluate whether duct stenting is associated with better survival and other clinical outcomes compared with the modified Blalock-Taussig shunt in infants with duct-dependent pulmonary flow., Methods: A systematic search of the Medline, Embase, and Cochrane databases was performed by 4 independent reviewers from inception to March 2019. Meta-analysis was performed using the DerSimonian and Laird method with inverse-variance weighting. The quality of evidence was summarized using the Grading of Recommendations, Assessment, Development, and Evaluation framework., Results: Six comparative observational studies were included, of which 3 were rated low risk of bias. There was no difference in 30-day mortality between the Blalock-Taussig shunt and duct stenting groups (risk ratio, 1.02; 95% confidence interval, 0.46-2.27; P = .96; I 2  = 0%). However, there was benefit in favor of duct stenting for medium-term mortality (risk ratio, 0.63; 95% confidence interval, 0.40-0.99; P = .05; I 2  = 0%). Duct stenting demonstrated a reduced risk for procedural complications compared with the Blalock-Taussig shunt (risk ratio, 0.50; 95% confidence interval, 0.31-0.81; P = .005; I 2  = 0%). However, there was an increased risk for unplanned reintervention for duct stenting (risk ratio, 1.77; 95% confidence interval, 1.39-2.26; P < .00001; I 2  = 10%). Duct stenting demonstrated shorter mean intensive care unit length of stay (mean difference, -4.69 days; 95% confidence interval, -7.30 to -2.07; P = .0004; I 2  = 80%), as well as shorter hospital length of stay (mean difference, -5.78 days; 95% confidence interval, -9.27 to -2.28; P = .0009, I 2  = 75%). The overall quality of evidence was rated low using the Grading of Recommendations, Assessment, Development, and Evaluation framework., Conclusions: Duct stenting demonstrated comparable early mortality, lower medium-term mortality, lower risk of procedural complications, and higher risk of reintervention compared with the Blalock-Taussig shunt., (Crown Copyright © 2020. Published by Elsevier Inc. All rights reserved.)

Background: In this study we sought to determine whether preoperative superior vena cava (SVC) blood flow measured using cardiac magnetic resonance (CMR) predicts physiology and clinical outcome after bidirectional cavopulmonary shunt (BCPS)., Methods: The retrospective single-center study included 65 (2012-2017) patients who underwent BCPS. Preoperative CMR imaging, echocardiography, catheterization, and clinical outcomes were reviewed. SVC flow was measured using phase contrast CMR. The Kaplan-Meier method and Cox regression was used for BCPS takedown-free survival and predictor analyses., Results: The absolute and indexed SVC flow was 0.5 (interquartile range [IQR], 0.4-0.7) L/min and 1.7 (IQR, 1.4-2.0) L/min/mm 2 respectively, which was comparable with the SVC blood flow volume previously measured. The median age and body weight at BCPS was 6.5 (IQR, 5.5-8.5) months and 6.9 (IQR, 6.0-7.7) kg. After follow-up, at a median of 17.1 (IQR, 7.9-41.3) months, 14 patients (21.5%) underwent the Fontan completion and 40 (61.5%) with BCPS physiology were waiting for the Fontan completion. The 11 remaining patients (16.9%), included those who underwent takedown (n = 7; 10.8%) or died with a BCPS (n = 4; 6.2%). Severe hypoxia was the leading cause of mortality, directly accounting for two-thirds of deaths (66.6%; 6/9). The BCPS takedown-free survival was 96.8% at 6 months, and 79.9% at 3 years. Preoperative SVC blood flow was significantly positively correlated with early post-BCPS arterial saturation (P = .00). The multivariable analysis showed SVC flow was the only factor associated with BCPS failure (hazard ratio, 0.186; P = .04) among the predictors related to the pre-BCPS anatomy and physiology., Conclusions: SVC blood flow might be as critically important as pulmonary artery anatomic and physiologic parameters in the evaluation of BCPS candidacy in the single-ventricle population., (Copyright © 2020 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: Data supporting the use of hands-on simulation in congenital heart surgery are promising but primarily qualitative. This study aimed to demonstrate if there was an objective improvement in time and technical performance of the arterial switch procedure on 3-dimensional printed heart models by surgeons using a validated assessment method., Methods: A total of 30 surgeons of varying experience performed the arterial switch procedure twice on 3-dimensional printed models with transposition of the great arteries during the Hands-on Surgical Training courses. Surgeons' performances were recorded and retrospectively assessed for both time and performance using the Hands-on Surgical Training-Congenital Heart Surgery tool, a validated procedure-specific assessment tool for the arterial switch., Results: A total of 60 videos were scored. Eighty percent of surgeons (24/30) had improved from their first attempt. The mean total score of the first attempt performance compared with the second was 103 and 120, respectively, with a mean difference in score of 17 (95% confidence interval, 10-24). All surgeons were statistically significantly quicker in their second attempt. The mean time for the first attempt compared with the second was 1 hour, 28 minutes, 4 seconds and 1 hour, 5 minutes, and 45 seconds, respectively, with a mean difference of 0 hours, 22 minutes, 19 seconds (95% confidence interval, 0 hours, 15 minutes, 22 seconds to 0 hours, 25 minutes, 34 seconds)., Conclusions: This is the first study to demonstrate an objective improvement in time and technical performance of the arterial switch procedure on 3-dimensional printed heart models. This supports the evidence that simulation in the form of deliberate practice with constructive, objective feedback is fundamental in the training of future congenital heart surgeons. These simulations and assessments should be incorporated to create structured, standardized training curricula within congenital heart surgery., (Crown Copyright © 2019. Published by Elsevier Inc. All rights reserved.)

Background: Hands-on surgical simulation has been sought to address training limitations within congenital heart surgery (CHS). However, there is a need for objective assessment methods to measure surgeons' performance to justify its global adoption. This study aimed to validate a procedure-specific assessment tool for the simulation of the arterial switch operation on 3D-printed models and to evaluate the consistency of scoring among evaluators with different levels of experience in CHS., Methods: Five "expert" and 5 "junior" surgeons performed the arterial switch procedure on 3D-printed models with transposition of the great arteries during 2 hands-on surgical training courses. Their performance was retrospectively assessed by 9 evaluators with varying experience in CHS (staff surgeons, resident surgeons, and non-MD raters). Assessments were done using 2 assessment tools: the Hands-On Surgical Training-Congenital Heart Surgery (HOST-CHS) assessment tool and the global rating scale (GRS)., Results: The HOST-CHS tool showed a higher interrater and intrarater reliability compared with the GRS. Total scores for expert surgeons were highly consistent across all evaluators. Non-MD raters' total scores for junior surgeons were slightly higher than those of residents and staff evaluators. All grades of evaluator were able to discriminate between junior and expert surgeons., Conclusions: This study demonstrates the development and validation of an objective, procedure-specific assessment tool for the arterial switch operation with consistency among evaluators with different experience. There is now a platform for quantifying and accurately evaluating performance, which will be highly beneficial in training and developing the next generation of congenital heart surgeons., (Copyright © 2019 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objectives: Adult patients who have undergone the Fontan procedure are highly vulnerable to gradual, progressive circulatory failure, and options to reverse this situation are few. A cavopulmonary assist device could decongest the venous and lymphatic systems, overcome elevated pulmonary vascular resistance, increase cardiac output, and support some of these patients to heart transplant. This study characterizes the performance and challenges of a novel multilumen cannula coupled to an external blood pump proposed as a potential Fontan cavopulmonary assist strategy., Methods: Computational fluid dynamic simulations were conducted for 3 extracardiac Fontan geometries consisting of 1 idealized model and 2 patient-specific models. A range of physiologic flow rates and pump assist levels were simulated to calculate the pressure gain provided by the multilumen cannula. Hemolysis index was estimated for the idealized model with Lagrangian particle tracking and 2 variations of the power-law. Wall shear stresses were also examined., Results: Pressure gains up to 4 and 9 mm Hg were achieved for the idealized and patient-specific models, respectively. Pressure gains increased with both higher cardiac output and larger pump intake through the external pump. Flow-weighted hemolysis show hemoglobin damage levels to be several times lower than the 2% threshold at the highest pump intake flow cases. Wall shear stress predictions depict elevated areas in the pulmonary vessels and regions of the cannula device., Conclusions: The cannula tested in this study shows promise as a percutaneous option to bridge support in some patients with a failing extracardiac Fontan. Limitations identified will be addressed in future design iterations and in ongoing experimental tests., (Copyright © 2019 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: We hypothesized that chylothorax could be a sign of intolerance to the Fontan physiology, and thus patients who develop chylothorax or pleural effusion have worse medium-term to long-term survival., Methods: A total of 324 patients who underwent the Fontan operation between 2000 and 2013 were included. Chylothorax was defined as ≥5 mL/kg/day of chylomicron-positive chest drainage fluid no earlier than postoperative day 5 or drainage with >80% lymphocytes. Outcomes were compared between the chylothorax and non-chylothorax groups by the Kaplan-Meier method and log-rank test. Independent predictors of chylothorax and number of days of any chest drainage were analyzed with multivariable logistic regression and multivariable generalized negative binomial regression for count data, respectively., Results: Chylothorax occurred in 78 patients (24%). Compared with the non-chylothorax group, the chylothorax group had a longer duration of chest tube requirement (median, 18 days vs 9 days; P < .000) and a longer length of hospital stay (median, 19 days vs 10 days; P < .000). Eight patients (10.3%) required thoracic duct ligation. The chylothorax group had lower freedom from death (P = .013) and from composite adverse events (P = .021). No predictor was found for chylothorax. Pulmonary atresia (P = .031) and pre-Fontan pulmonary artery pressure (P = .01) were predictive of prolonged pleural effusion (>14 days)., Conclusions: Occurrence of chylothorax following the Fontan operation can be a marker of poorer medium-term clinical outcomes. It is difficult to predict occurrence of chylothorax owing to its multifactorial nature and involvement of lymphatic compensatory capacity that is unmasked only after the Fontan operation., (Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: In this single-center study, we sought to determine the frequency of phrenic nerve injury leading to diaphragm paresis (DP) in children following open cardiac surgery over the last 10 years, and to identify possible variables that predict the need for plication and associated clinical outcomes., Methods: Patients diagnosed with DP were identified from departmental databases and a review of clinical diaphragm ultrasound images. A cohort was analyzed for predictors of diaphragm plication and associations with clinical outcomes. Cumulative proportion graphs modeled the association between plication and length of stay., Results: DP was diagnosed in 161 of 6448 patients (2.5%) seen between January 2002 and December 2012. All diagnoses but 1 were confirmed by ultrasound. Plication of the diaphragm was performed in 30 patients (19%); compared with patients who did not undergo plication, these patients were younger (median age, 10 days vs 138 days; P < .001), more likely to have undergone deep hypothermic circulatory arrest (47% vs 18%; P = .005), had a longer duration of positive pressure ventilation (median, 15 days vs 7 days; P < .001), and had longer lengths of stay in both the intensive care unit (median, 23 days vs 8 days; P < .0001) and the hospital (median, 37 days vs 15 days; P < .0001). Early plication was associated with reduction in all intervals of care., Conclusions: Early plication should be considered for patients with diaphragm paresis requiring prolonged respiratory support after cardiac bypass surgery. Longer follow-up evaluation is required to better define the long-term implications of plication., (Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: The interdigitating technique in aortic arch reconstruction in hypoplastic left heart syndrome and variants (HLHS) reduces the recoarctation rate. Little is known on aortic arch growth characteristics and resulting clinical impact., Methods: A total of 139 patients with HLHS underwent staged palliation between 2007 and 2014; 73 patients underwent arch reconstruction. Dimensions of ascending aorta, transverse arch, interdigitating anastomosis, and descending aorta in pre-stage II and pre-Fontan angiograms were measured. Aortic arch dimensions were analyzed. Ventricular and atrioventricular valve function were assessed., Results: Diameters increased in all segments between pre-stage II and pre-Fontan (P < .0005). The z scores remained unchanged in all segments but the descending aorta that was significantly larger pre-Fontan (P = .039). Dimensions and z scores between pre-stage II and pre-Fontan correlated in proximal segments, but not at and distal to the interdigitating anastomosis. Pronounced tapering occurred between the transverse arch and the interdigitating anastomosis. Arch intervention of any type was performed in 7 (9.6%), and intervention for recoarctation in 3 (4.1%) patients., Conclusions: The aortic arch after reconstruction with the interdigitating technique differs from normal. Growth was proportional with no further geometrical distortion. Recoarctation and reintervention rate is low. Further improvement may be achieved by optimizing patch configuration and material., (Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: Poor survival following surgical palliation for hypoplastic left heart syndrome (HLHS) raises the question of the need for a paradigm shift. This is the first human study to investigate the possibility of primary "in-series" palliation in neonates and infants with HLHS in an acute setting with the aid of 2 types of mechanical assist: superior vena cava (SVC)-to-pulmonary artery (PA) pump assist and SVC-to-right atrium (RA) oxygenation assist., Methods: By rearranging the cannula sites and flow rates for modified ultrafiltration, 2 types of mechanically assisted bidirectional cavopulmonary shunt (BCPS) circulation were simulated for 20 minutes. Three neonates undergoing a stage I Norwood procedure were assigned to SVC-PA pump assist, and 3 infants undergoing stage II BCPS were assigned to SVC-RA oxygenation assist. Hemodynamic parameters, blood gas values, and arterial (SaO 2 ) and regional cerebral tissue (rCTO 2 ) saturations were analyzed., Results: All 6 patients completed the study without hemodynamic compromise. In the SVC-PA pump assist group, a mean arterial pressure >40 mm Hg was maintained. SVC pressure was lower (P = .01) and cerebral perfusion pressure (CPP) was higher (P = .03) during the last 10 minutes of assist compared with Norwood physiology. SaO 2 >80%, rCTO 2 >60%, and mixed venous saturation ≥59% were maintained, comparable to values with Norwood physiology. In the SVC-RA oxygenation assist group, with full or 50% support, mean blood pressure >50 mm Hg, SVC pressure <15 mm Hg, mixed venous saturation >50%, and CPP >40 mm Hg were maintained, which were comparable to BCPS physiology., Conclusions: Two types of mechanical assist to support primary in-series palliation are feasible in the acute setting. Both modes of mechanical assist maintained oxygenation, as well as systemic and cerebral perfusion., (Copyright © 2016. Published by Elsevier Inc.)

Background: We hypothesized that mean pulmonary artery pressure (PAP) detected on a pulmonary flow study may predict medium-term survival and right ventricular systolic pressure (RVSP) in patients with pulmonary atresia (PA), ventricular septal defect (VSD), and major aortopulmonary collateral arteries (MAPCAs)., Methods: Fifty patients with PA/VSD/MAPCAs underwent unifocalization between 2000 and 2013, and 40 of these patients had a pulmonary flow study since 2003. Predictability of the mean PAP on VSD status, medium-term survival, reintervention, and RVSP were analyzed., Results: Forty-seven of the 50 patients (94%) had complete unifocalization at a median age of 11 months (range, 1-194 months), and 37 patients (74%) achieved VSD closure. Among the 40 patients who underwent a pulmonary flow study, the VSD was closed in 34 (85%), with salvage VSD fenestration in 4 (10%), and was intentionally left open in 6 (15%). Survival was 85.5% at 1 year and 78.5% at 5 years. A mean PAP ≥25 mm Hg was associated with worse survival (P = .011). Cox regression analysis identified a mean PAP ≥25 mm Hg as the sole predictor for death (P = .037). Patients with an open VSD had an increased risk of reoperation (P = .001) and pulmonary artery reintervention (P = .010), and had a trend toward increased risk of death (P = .059), compared with those with a closed VSD., Conclusions: PAP obtained from the intraoperative pulmonary flow study is associated with medium-term survival and late RVSP in patients with PA/VSD/MAPCAs. VSD closure for patients with a mean PAP ≥25 mm Hg on a flow study is considered high risk, and sensible judgment and a low threshold for VSD fenestration are required., (Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Size mismatch between body and a systemic-to-pulmonary shunt can result in excessive pulmonary blood flow, compromising systemic oxygen delivery. Previously reported techniques to mechanically restrict shunt flow lack precision and reproducibility. We developed a formula for shunt banding and assessed its efficacy and reproducibility by in vitro and clinical measurements., Methods: Formulas to determine diameter reduction, length of banding, and effect on the ratio of pulmonary blood flow (Q p ) to systemic blood flow (Q s ) were established. In vitro measurements of different shunt grafts were performed. Results were compared with calculations and clinical data. Clinical outcome was retrospectively assessed in all patients (n = 8) who underwent a shunt banding procedure at our institution between 2008 and 2012., Results: Our formulas can adequately predict the length of the band based on the desired diameter and shunt type or on the Q p :Q s mismatch. In vitro measurements correlated with the manufacturer's specifications in small shunts (≤5 mm diameter; 0.45 mm mean wall thickness). The calculated diameters of these shunts were closely correlated with in vitro measurements (r = 0.953; P = .001). Arterial saturation, pH, and calculated Q p :Q s decreased significantly with banding (P = .026, .002, and .004, respectively). Clinical effects varied among patients, with hemodynamically stable patients achieving the most benefit. Adjustment of the band was required in 1 patient. No shunt thrombosis or shunt banding-related complications were noted., Conclusions: Our formulas and surgical strategy offer a new approach to controlling excessive pulmonary blood flow in shunt-dependent circulations in an effective and predictable way. The best reproducibility was achieved in small, thin-walled shunts. This strategy was most effective in patients with pulmonary overcirculation without hemodynamic decompensation., (Copyright © 2016. Published by Elsevier Inc.)

Objectives: Pulmonary vein characteristics that influence survival after repair of stenosis have not been defined. We sought to develop a predictive model relating postrepair survival to preoperative pulmonary vein characteristics on computed tomography and magnetic resonance imaging., Methods: Patients who underwent pulmonary vein stenosis repair (1990-2012) with preoperative computed tomography and magnetic resonance imaging were reviewed. We measured pulmonary vein short and long cross-sectional diameters at the left atrial junction (downstream), vein bifurcation (upstream), and narrowest point, and calculated the total cross-sectional area indexed for body surface area. The relationship between pulmonary vein dimensions and survival was related via risk-adjusted parametric hazard analyses., Results: Of 145 patients who underwent surgical repair, 31 had preoperative computed tomography and magnetic resonance imaging and were analyzed. Surgical repairs were sutureless (n = 30) or pericardial patch reconstruction (n = 1). Mean follow-up was 4.28 ± 4.2 years. In-hospital mortality was 9.7%; unadjusted survival was 75% ± 7%, 69% ± 8%, and 64% ± 7% at 1, 3, and 5 years, respectively. Median downstream total cross-sectional area indexed for body surface area was 163 mm(2)/m(2), upstream total cross-sectional area indexed for body surface area was 263 mm(2)/m(2), and total cross-sectional area indexed for body surface area at maximal stenosis, localized at the left atrial junction in approximately two thirds of patients, was 163 mm(2)/m(2). Smaller upstream total cross-sectional area indexed for body surface area (P = .030) and greater number of stenotic pulmonary veins (P = .0069) were associated with increased early (<1 year) risk of death. Smaller downstream total cross-sectional area indexed for body surface area tended to be associated with a late risk of death (P = .059)., Conclusions: Smaller upstream or downstream total cross-sectional area indexed for body surface area negatively influenced survival. Early survival seemed especially poor for patients with a greater number of stenotic veins and upstream pulmonary vein involvement. The total cross-sectional area indexed for body surface area measurements can help to inform prognosis and stratify patients for enrollment in clinical trials of agents directed at pulmonary vein pathology., (Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Patients with single-ventricle physiology frequently develop left-sided pulmonary vein obstruction (PVO), in which the pulmonary veins traverse the descending thoracic aorta. We hypothesized that a combination of cardiomegaly and an anteriorly positioned descending aorta is associated with PVO., Methods: Among 494 consecutive single-ventricle patients, 15 were diagnosed with PVO by cardiac magnetic resonance, defined as anatomically localized narrowing of the pulmonary vein diameter. Using axial slices at the level of the left lower pulmonary vein, normalized dimensions were obtained to characterize the anatomic relationships of intrathoracic structures. Measurements were compared between patients with PVO and "control" patients (single-ventricle patients with normal pulmonary veins, n = 12)., Results: Patients with cardiac magnetic resonance-diagnosed PVO had larger cardiac size and more antero-laterally located descending aorta when compared with controls (normalized dimensions: cardiac/thoracic area ratio: 0.43 vs 0.38, P = .035, distance from vertebra to descending aorta normalized by the horizontal dimension of thoracic cavity: 0.09 vs 0.08, P = .049). Seven (47%) patients underwent PV sutureless repair, and 3 (of 7) failed to achieve Fontan. Patients who failed to achieve Fontan had a larger normalized cardiac size than those who achieved Fontan (cardiac/thoracic area ratio: 0.49 vs 0.39, P = .001)., Conclusions: The combination of relative cardiomegaly within the context of the thoracic cavity at the level of the pulmonary veins and antero-lateral displacement of the aorta is associated with left-sided PVO and subsequent failure to achieve Fontan completion. Further characterization of these unique geometric relationships may help inform both surveillance strategies and decision making in the timing of interventions, and guide the intraoperative objectives at the time of PVO repair., (Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: Pulmonary artery growth is an important determinant of outcome in single-ventricle strategies. Higher rates of pulmonary artery intervention have been reported with hybrid-based palliation when compared with Norwood palliation., Methods: We performed a retrospective review of pulmonary artery growth and clinical outcomes in patients undergoing hybrid-based single-ventricle palliation., Results: The stage I hybrid procedure was performed in 72 patients between 2004 and 2012, of whom 54 were on a Fontan palliative pathway. Thirty-four infants completed stage II, and 20 infants underwent the Fontan operation. The mean diameters of the right pulmonary artery (5.6 ± 1.9 mm) and left pulmonary artery (5.6 ± 2.1 mm) were similar before stage II. After stage II, the right and left pulmonary artery diameters were 8.5 ± 2.1 mm and 5.8 ± 1.3 mm, respectively (P < .001), and after the Fontan operation, these were 8.8 ± 2.0 mm and 6.4 ± 1.1 mm, respectively (P = .002). The mean right pulmonary artery z score was normal throughout, but the left pulmonary artery did not maintain a normal size. The cumulative pulmonary artery intervention rate was 50% at any time after stage II. Fifteen interventions (88%) were performed after stage II (35% during the same hospitalization, 71% <60 days). The most intervened site was the midsection of the left pulmonary artery (41%). Initial pulmonary artery intervention was balloon dilation in 59% of patients and stent implantation in 41% of patients. Half of patients with initial balloon dilation required reintervention., Conclusions: There is significant risk of left pulmonary artery compromise after the second stage of hybrid palliation associated with a high intervention rate., (Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: We sought to evaluate the medium-term implications of fenestration status., Methods: Between 1994 and 2012, 326 patients received an extracardiac Fontan (hospital mortality n = 6, 1.8%). A fenestration was routinely created (n = 306, 94%) unless there was technical difficulty. Three hundred patients discharged with an open fenestration were included. The primary end points were death and Fontan failure. Secondary outcomes were Fontan complications such as venovenous collaterals, protein-losing enteropathy, pacemaker requirement, and arrhythmias., Results: The fenestration was closed in 260 patients: 185 as a catheter intervention (62%) and 75 (25%) spontaneously. Forty patients (13%) had the fenestration open at a median follow-up period of 5.05 years. Of these patients, catheter-based closure failed in 10 (3%). There was no statistically significant difference in pre-Fontan hemodynamic parameters, such as pulmonary artery pressure and pulmonary vascular resistance between the patients with open fenestration and the ones with closed fenestration. Patients with an open fenestration had significantly more late deaths (P < .001), Fontan failure (P = .021), and Fontan complications (P = .011) compared with those with a closed fenestration. Multivariable Cox regression revealed open fenestration (P < .001) and indeterminate ventricular morphology (P = .002) as risk factors for death/Fontan failure, and ventricular dysfunction (P = .014) and open fenestration (P = .009) as risk factors for Fontan complications., Conclusions: Persistent fenestration was a marker for physiologic intolerance as noted by increased rates of mortality and a higher incidence of Fontan failure/complications. The specificity of pre-Fontan physiologic data for fenestration status may not have the fidelity needed for long-term care and thus, the consequences of decision making regarding fenestration status may not be determined until well after the operation., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: Despite improved long-term survival after pediatric heart transplantation, perioperative mortality has remained high. We sought to understand the factors associated with perioperative graft loss after pediatric heart transplantation., Methods: The factors associated with primary heart transplant mortality and retransplantation before hospital discharge in 226 pediatric heart transplant recipients (1995-2010) at a single-center institution were analyzed using multivariable logistic regression models adjusted for age at surgery and year of surgery., Results: A total of 26 patients died (n = 21) or underwent retransplantion (n = 5) before hospital discharge secondary to primary graft failure (n = 10), multisystem organ failure (n = 5), infection (n = 4), rejection (n = 2), and perioperative complications (n = 5). United Network for Organ Sharing status 1 (vs status 2) at transplantation was associated with an increased odds of death from noncardiac causes (odd ratio [OR], 4.7; 95% confidence level [CI], 1.2-22.3; P = .002). The factors associated with increased odds of perioperative mortality or retransplant were pre- and post-transplant extracorporeal membrane oxygenation (OR, 5.3; 95% CI, 1.5-18.7; P = .01; and OR, 25.9; 95% CI, 7.0-95.9; P < .001), longer ischemic times (OR, 1.4 per 30 minutes; 95% CI, 1.0-2.0; P = .04), reoperation after transplantation (OR, 3.5; 95% CI, 1.2-10.4; P = .02), and transplantation before 2002 (OR, 4.5; 95% CI, 1.4-14.9; P = .01), respectively., Conclusions: The use of extracorporeal membrane oxygenation (both before and after transplantation), a longer ischemic time, and reoperation were key factors associated with perioperative graft loss, with noncardiac mortality closely related to United Network for Organ Sharing status at heart transplantation. Knowledge of the perioperative risk factors and how they affect graft survival will help guide difficult decisions around eligibility, timing of primary listing, and appropriateness for retransplantation, and potentially affect long-term survival., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: The management of patients with tetralogy of Fallot (ToF) and pulmonary atresia (PA) with major aortopulmonary collateral arteries (MAPCAs) is challenging. Frequently it is difficult to predict whether complete repair with closure of the ventricular septal defect (VSD) will be tolerated. The aim of this study was to investigate whether measurements of preoperative pulmonary blood flow are associated with early postoperative outcome after VSD closure., Methods: In this retrospective study, the data from 10 patients who had undergone a cardiac magnetic resonance imaging study with flow measurements before attempted surgical complete repair were collected. Systemic blood flow (Qs) was calculated as the sum of descending aortic blood flow distal to the MAPCA origins and superior vena cava flow. Pulmonary blood flow (Qp) was measured either from the sum of the pulmonary flow (n = 7) or calculated as the difference between ascending aortic flow and Qs., Results: Preoperative Qp/Qs averaged 1.71 ± 0.68 and correlated inversely with right ventricular systolic pressure (relative to systolic blood pressure, r = -0.75, P = .03) and positively with the total neopulmonary artery index (TNPAI, r = 0.66, P = .04), as measured by fluoroscopic angiography. Two children did not tolerate VSD closure. This was likely related to bronchial compression in 1 patient while the other had the lowest TNPAI and the lowest Qp/Qs of all patients., Conclusions: CMR provides not only anatomic but also functional information for surgical decision making in patients with ToF and PA with MAPCAs. Preoperative Qp/Qs is associated with postoperative right ventricular pressure and may be a marker of readiness for VSD closure., (Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: Retrograde aortic arch malperfusion after ductal stenting can be life-threatening after univentricular hybrid palliation. Arch perfusion can be maintained with a main pulmonary artery to innominate artery shunt placed during the stage I procedure: a "reverse Blalock-Taussig shunt.", Methods: A retrospective review of 37 infants who underwent hybrid palliation from January 2004 to March 2010 was performed. The infants were divided into 2 groups, those with (group I, n = 16) and those without (group II, n = 21) a reverse Blalock-Taussig shunt., Results: At the initial palliation, no differences were found in the demographics, systolic or diastolic pressures, or ventricular or atrioventricular valve function between the 2 groups. Group I had more infants with aortic atresia (P < .01) and smaller ascending aortas (P < .01). Before stage II, the retrograde aortic Doppler flow velocity increased in group I (P < .01) and was unchanged in group II. The reintervention rates before stage II were similar between the 2 groups. Before stage II, the ventricular end-diastolic pressure, left and right pulmonary artery pressures and diameters, and mixed venous and arterial saturations were similar between the 2 groups. The complication rates between the 2 groups were not significantly different, although a nonsignificant trend toward more neurologic complications was noted in group I. The Kaplan-Meier survival estimate at 1 year was similar between the 2 groups (63% for group I vs 71% for group II)., Conclusions: The presence of a reverse Blalock-Taussig shunt was not associated with more adverse events than those without. Gradual retrograde arch obstruction occurs commonly in palliated infants with aortic atresia. A reverse Blalock-Taussig shunt might play an important role to address the potential of retrograde obstruction, augmenting arch blood flow., (Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objectives: We sought to elucidate late functional outcomes of the right ventricular outflow tract and atrioventricular valves after repair of tetralogy of Fallot with atrioventricular septal defect., Methods: From 1990 to 2010, the data from 41 patients who underwent repair were retrospectively reviewed. The median age at repair was 22.4 months (interquartile range, 10.8-41.6 months). Of the 41 patients, 13 (32%) had received previous palliations. The preoperative anatomic differences, physiologic differences, and long-term functional outcomes were determined using a double case-matched control with isolated tetralogy of Fallot and isolated atrioventricular septal defect., Results: The right ventricular outflow tract was reconstructed, with the pulmonary valve preserved in 23 patients (56%). There were 3 early deaths and no late deaths. Survival was 92.1% at 15 years. During a median follow-up period of 5.9 years (interquartile range, 0.14-13.7 years), 29 reinterventions were performed in 13 (32%) patients. Freedom from all reintervention at 15 years was 52.8%. Of the 29 procedures, 12 (41%) were related to the right ventricular outflow tract. Freedom from right ventricular outflow tract-related reintervention was greater in patients who had their pulmonary valve preserved (95% vs 70% at 10 years; P = .046). Reinterventions were performed for the atrioventricular valve in 2 (5%) patients and subaortic stenosis in 1 (2%) patient. Freedom from right ventricular outflow tract-related reintervention (tetralogy of Fallot with atrioventricular septal defect, 88.6% vs tetralogy of Fallot alone, 83.9% at 5 years; P = .809) and atrioventricular valve/left ventricular outflow tract-related reintervention (tetralogy of Fallot with atrioventricular septal defect, 95.2% vs atrioventricular septal defect alone, 86.0% at 5 years; P = .332) were comparable between the tetralogy of Fallot with atrioventricular septal defect and matched control groups., Conclusions: Late survival and atrioventricular valve function after repair of tetralogy of Fallot with atrioventricular septal defect were excellent. Pulmonary valve preservation and avoidance of an artificial conduit were associated with greater freedom from right ventricular outflow tract reintervention. In the current era, the surgically modified history of tetralogy of Fallot with atrioventricular septal defect is not significantly different from that of isolated tetralogy of Fallot or isolated atrioventricular septal defect., (Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objectives: Chronic right ventricular (RV) pressure overload results in pathologic RV hypertrophy and diminished RV function. Although aortic constriction has been shown to improve systolic function in acute RV failure, its effect on RV responses to chronic pressure overload is unknown., Methods: Adjustable vascular banding devices were placed on the main pulmonary artery and descending aorta. In 5 animals (sham group), neither band was inflated. In 9 animals (PAB group), only the pulmonary arterial band was inflated, with adjustments on a weekly basis to generate systemic or suprasystemic RV pressure at 28 days. In 9 animals, both pulmonary arterial and aortic devices were inflated (PAB + AO group), the pulmonary arterial band as for the PAB group and the aortic band adjusted to increase proximal systolic blood pressure by approximately 20 mm Hg. Effects on the functional performance were assessed 5 weeks after surgery by conductance catheters, followed by histologic and molecular assessment., Results: Contractile performance was significantly improved in the PAB + AO group versus the PAB group for both ventricles. Relative to sham-operated animals, both banding groups showed significant differences in myocardial histologic and molecular responses. Relative to the PAB group, the PAB + AO group showed significantly decreased RV cardiomyocyte diameter, decreased RV collagen content, and reduced RV expression of endothelin receptor type B, matrix metalloproteinase 9, and transforming growth factor β genes., Conclusions: Aortic constriction in an experimental model of chronic RV pressure overload not only resulted in improved biventricular systolic function but also improved myocardial remodeling. These data suggest that chronically increased left ventricular afterload leads to a more physiologically hypertrophic response in the pressure-overloaded RV., (Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: This study was to determine whether atrioventricular valve repair modifies natural history of single-ventricle patients with atrioventricular valve insufficiency and to identify factors predicting survival and reintervention., Methods: Fifty-seven (13.5%) of 422 single-ventricle patients underwent atrioventricular valve repair. Valve morphology, regurgitation mechanism, and ventricular morphology and function were analyzed for effect on survival, transplant, and reintervention with multivariate logistic and Cox regression models. Comparative analysis used case-matched controls., Results: Atrioventricular valve was tricuspid in 67% and common in 28%. Ventricular morphology was right in 83%. Regurgitation mechanisms were prolapse (n = 24, 46%), dysplasia (n = 18, 35%), annular dilatation (n = 8, 15%), and restriction or cleft (n = 2, 4%). Postrepair insufficiency was none or trivial in 14 (26%), mild in 33 (61%), and moderate in 7 (13%). Survival in repair group was lower than in matched controls (78.9% vs 92.7% at 1 year, 68.7% vs 90.6% at 3 years, P = .015). Patients with successful repair and normal ventricular function had equivalent survival to matched controls (P = .36). Independent predictors for death or transplant included increased indexed annular size (P = .05), increased cardiopulmonary bypass time (P = .04), and decreased postrepair ventricular function (P = .01). Ventricular dilation was a time-related factor for all events, including failed repair., Conclusions: Survival was lower in single-ventricle patients operated on for atrioventricular valve insufficiency than in case-matched controls. Patients with little postoperative residual regurgitation and preserved ventricular function had equivalent survival to controls. Lower grade ventricular function and ventricular dilation correlated with death and repair failure, suggesting that timing of intervention may affect outcome., (Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: We reported a high incidence of thrombosis, central pulmonary artery hypoplasia, and mortality for bilateral bidirectional cavopulmonary shunts. We hypothesized that technical modifications in the cavopulmonary anastomosis and anticoagulation would limit thrombus and central pulmonary artery hypoplasia, and thereby improve outcomes., Methods: Sixty-one patients (median age, 8.4 months; weight, 6.6 kg) underwent bilateral bidirectional cavopulmonary shunt from 1990 to 2007. The cohort was divided into 2 groups: 1) the conventional group (1990-1999, n = 37) and 2) the V-shaped group, with a hemi-Fontan or modification in which the cavae were anastomosed to the pulmonary artery adjacent to each other so they formed the appearance of a V (1999-2007, n = 24). Central and branch pulmonary artery growth, survival, and reinterventions were determined., Results: The pre-Fontan study showed equivalent superior venae cavae and Nakata indices. The central pulmonary artery index and central pulmonary artery/Nakata index ratio were significantly higher in the V-shaped group (P < .05). There were no differences in freedom from death or transplant (conventional 69% vs V-shaped 75% at 3 years, P = .5), and a nonsignificant trend toward improving freedom from reinterventions (63% vs 81% at 3 years, P = .15) and thrombosis (82% vs 95% at 1 year, P = .11) was observed in the V-shaped group. Multivariate analysis showed anastomotic strategy, low saturation, and thrombosis were predictors for death. Anastomotic strategy, lack of anticoagulation, thrombosis, and small superior venae cavae were predictors for reintervention (P < .05). Predictors for thrombus included small superior venae cavae, Nakata index, and low saturation (P < .03)., Conclusions: Surgical modifications for bilateral bidirectional cavopulmonary shunts were associated with the larger central pulmonary artery size. Lack of anticoagulation and anastomotic strategy affected reintervention. Anastomotic strategy and postoperative thrombus affected mortality., (2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objectives: We tested mechanical cavopulmonary blood flow assist by incorporating a novel miniature centrifugal pump into a 1(1/2)-ventricle type cavopulmonary connection in neonatal pigs., Methods: Nine 3-week-old piglets (mean body weight, 10.2 kg) were used: mechanical cavopulmonary assist (n = 6) and controls (n = 3). A bidirectional cavopulmonary connection between the superior vena cava and the main pulmonary artery was created. The superior vena cava and pulmonary artery were also connected by cannulas with an interposed centrifugal pump. The cavoarterial mechanical cavopulmonary assist was performed at pump speeds of 1500, 2000, 2500, and 3000 rpm. Retrograde superior vena caval flow was limited by a band on the superior vena cava. A bidirectional cavopulmonary connection was created in the control animals, which then had a pure 1(1/2)-ventricle repair physiology without mechanical support. Hemodynamics, blood gas, and cerebral blood flow measured by ultrasound were analyzed. Catheter-based dilatation of the surgically created superior vena cava obstruction was tested., Results: Incremental increases in pump speed augmented bidirectional cavopulmonary shunt blood flow (P =.03) and diminished superior vena caval pressure (P =.03), thereby improving cerebral perfusion pressure. Pump flow of 3000 rpm was equivalent to baseline superior vena caval flow (before caval flow, 392 +/- 48 mL/min vs MCPA, 371 +/- 120 mL/min; mean +/- SD; P = not significant). The mechanical cavopulmonary assist group had higher Doppler velocities of the middle cerebral artery and higher transcerebral oxygen difference(P < .05) than controls. Balloon dilatation of the superior vena cava band was successful., Conclusions: Mechanical cavopulmonary assist maintained bidirectional cavopulmonary shunt flow, thereby sustaining primary bilateral cavopulmonary shunt physiology in a neonatal pig model of high pulmonary vascular resistance. The mechanical cavopulmonary assist maintained cerebral blood flow and metabolism with an adequate transcerebral pressure gradient.

Objective: Mitochondrial permeability transition pore opening plays a critical role in mediating the mitochondrial response to ischemia/reperfusion injury and initiation of apoptosis. We tested whether inhibition of mitochondrial permeability transition pore opening with cyclosporine A prevented apoptosis-related alterations in mitochondrial structure and function after cardioplegic arrest., Methods: Newborn piglets (age approximately 14 days) underwent cardiopulmonary bypass, cardioplegic arrest (60 minutes), weaning from bypass, and 6-hour reperfusion. Comparison was made among cold crystalloid cardioplegia (n = 5), cold crystalloid cardioplegia with cyclosporine A pretreatment (n = 5), and noncardiopulmonary bypass (n = 5) groups., Results: Early apoptosis signaling events (Bax translocation to the mitochondria) were prominent in cold crystalloid cardioplegia and prevented in cold crystalloid cardioplegia + cyclosporine A myocardium. Mitochondrial release of cytochrome c, determined by Western blot of cytosolic fractions and confocal quantitative colocalization analysis, was also prominent in cold crystalloid cardioplegia but prevented in cold crystalloid cardioplegia + cyclosporine A myocardium. Electron microscopy of isolated mitochondria demonstrated subjective alterations in mitochondrial architecture in cold crystalloid cardioplegia mitochondria, which were prevented by cyclosporine A. Deficiency of isolated mitochondrial oxygen consumption at Complex I was present in cold crystalloid cardioplegia mitochondria and prevented by cyclosporine A (P < .01). The frequency of deoxyuride-5'-triphosphate biotin nick end labeling-positive myocytes was diminished in cold crystalloid cardioplegia + cyclosporine A myocardium (P < .05). Mitochondrial resistance to calcium-mediated mitochondrial permeability transition pore opening was not different in cold crystalloid cardioplegia and noncardiopulmonary bypass mitochondria, suggesting that calcium overload is not solely responsible for the observed deficits in mitochondrial function., Conclusions: Cyclosporine A pretreatment prevents postcardioplegia alterations in mitochondrial structure and function in a clinically relevant model of neonatal cardiac surgery. Prevention of mitochondrial permeability transition pore opening and apoptosis signaling events (Bax translocation and mitochondrial permeabilization) are associated with superior mitochondrial preservation.