Surgical Outcomes in Patients Undergoing a Double Switch Operation for Corrected Transposition.

BACKGROUND: Congenitally corrected transposition of the great arteries (CC-TGA) is a rare and complex form of congenital heart disease. Results of physiologic repair proved disappointing due to late right ventricular dysfunction and/or tricuspid regurgitation. The current study was performed to evaluate surgical outcomes in patients undergoing a double switch for CC-TGA. METHODS: This was a retrospective review of 121 patients who underwent a double switch over a 2-decade time frame (2002-2023). Patients were a median age of 32 months. Before the double switch, 49 of 121 patients (40%) had undergone left ventricular retraining. RESULTS: Sixty-seven patients underwent an arterial switch, and 54 underwent a Rastelli procedure. There were 4 in-hospital deaths (3.3%), including 3 who had a Rastelli procedure (5.6%) and 1 who had an arterial switch (1.5%). At a median follow-up of 30 months, there were 4 late deaths (2 Rastelli and 2 arterial switch). Combined early and late mortality was 9.3% for the Rastelli and 4.5% for arterial switch. Combined mortality was 2.0% for patients who required left ventricular retraining vs 9.7% for those who did not. For the 117 patients discharged from the hospital, 93% have normal or low-normal left ventricular function, and 96% have mild or less neoaortic insufficiency. CONCLUSIONS: Surgical outcomes in patients undergoing a double switch procedure have been excellent both in the short- and midterm. However, the Rastelli procedure was associated with a more than 2-fold increase in mortality risk compared with the arterial switch.

Right Ventricular and Outflow Tract Functional Characteristics After Repair of Tetralogy of Fallot with Major Aortopulmonary Collaterals.

This study describes right ventricle (RV) characteristics and right ventricle to pulmonary artery (RV-PA) conduit function pre- and post-repair in patients with tetraology of Fallot with major aortopulmonary collaterals (TOF/MAPCAs). We reviewed patients who underwent single-stage, complete unifocalization, and repair of TOF/MAPCAs between 2006 and 2019 with available pre- and early postoperative echocardiograms. For a subset of patients, 6-12 month follow-up echocardiogram was available. RV and left ventricle (LV) characteristics and RV-PA conduit function were reviewed. Wilcoxon signed rank test and McNemar's test were used. 170 patients were reviewed, 46 had follow-up echocardiograms. Tricuspid valve annular plane systolic excursion (TAPSE) Z-scores were reduced from pre- (Z-score 0.01) to post-repair (Z-score -4.5, p < 0.001), improved but remained abnormal at follow-up (Z-score -4.0, p < 0.001). RV fractional area change (FAC) and LV ejection fraction were not significantly different before and after surgery. Conduit regurgitation was moderate or greater in 11% at discharge, increased to 65% at follow-up. RV-PA conduit failure (severe pulmonary stenosis or severe pulmonary regurgitation) was noted in 61, and 63% had dilated RV (diastolic RV area Z-score > 2) at follow-up. RV dilation correlated with the severe conduit regurgitation (p = 0.018). Longitudinal RV function was reduced after complete repair of TOF/MAPCAs, with decreased TAPSE and preserved FAC and LV ejection fraction. TAPSE improved but did not normalize at follow-up. Severe RV-PA conduit dysfunction was observed prior to discharge in 11% of patients and in 61% at follow-up. RV dilation was common at follow-up, especially in the presence of severe conduit regurgitation.

Results of the Double Switch Operation in Patients Who Previously Underwent Left Ventricular Retraining.

BACKGROUND: Congenitally corrected transposition of the great arteries (CC-TGA) is a complex form of congenital heart disease that has numerous subtypes. While most patients with CC-TGA have a large ventricular septal defect (VSD) and pulmonary stenosis, there are some patients who have either no VSD or a highly restrictive VSD. These patients will require left ventricular (LV) retraining prior to double switch. The purpose of this study was to review our experience with the double switch procedure in patients who had previously undergone LV retraining. METHODS: This was a retrospective review of a single institution experience with the double switch procedure in patients who had undergone LV retraining (2002-present). RESULTS: Forty-five patients underwent double switch following LV retraining. Of these, 39 had an arterial switch with hemi-Mustard/bidirectional Glenn and six had a Senning. The median cross-clamp time was 135 min (range 71-272) and median bypass time was 202 min (range 140-430 min). Median hospital length of stay was eight days (range 4-108). There were no in-hospital deaths. Median duration of follow-up was 30 months (range 0-175). One patient subsequently underwent heart transplantation and died 65 months following double switch. At follow-up, 41 of the 44 survivors (93%) have normal or low normal LV function and 40 of the 44 survivors (91%) have no or trace mitral regurgitation. CONCLUSIONS: The data demonstrate early and mid-term survival of 100% and 97%. Ninety-three percent had preserved LV function. These results suggest that patients with CC-TGA who undergo LV retraining and double switch can have excellent clinical outcomes.

20-Year Experience With Repair of Pulmonary Atresia or Stenosis and Major Aortopulmonary Collateral Arteries.

BACKGROUND: We have followed a consistent, albeit evolving, strategy for the management of patients with pulmonary atresia or severe stenosis and major aortopulmonary collateral arteries (MAPCAs) that aims to achieve complete repair with low right ventricular pressure by completely incorporating blood supply and relieving stenoses to all lung segments. OBJECTIVES: The purpose of this study was to characterize our 20-year institutional experience managing patients with MAPCAs. METHODS: We reviewed all patients who underwent surgery for MAPCAs and biventricular heart disease from November 2001 through December 2021. RESULTS: During the study period, 780 unique patients underwent surgery. The number of new patients undergoing surgery annually was relatively steady during the first 15 years, then increased substantially thereafter. Surgery before referral had been performed in almost 40% of patients, more often in our recent experience than earlier. Complete repair was achieved in 704 patients (90%), 521 (67%) during the first surgery at our center, with a median right ventricular to aortic pressure ratio of 0.34 (25th, 75th percentiles: 0.28, 0.40). The cumulative incidence of mortality was 15% (95% CI: 12%-19%) at 10 years, with no difference according to era of surgery (P = 0.53). On multivariable Cox regression, Alagille syndrome (HR: 2.8; 95% CI: 1.4-5.7; P = 0.004), preoperative respiratory support (HR: 2.0; 95% CI: 1.2-3.3; P = 0.008), and palliative first surgery at our center (HR: 3.5; 95% CI: 2.3-5.4; P < 0.001) were associated with higher risk of death. CONCLUSIONS: In a growing pulmonary artery reconstruction program, with increasing volumes and an expanding population of patients who underwent prior surgery, outcomes of patients with pulmonary atresia or stenosis and MAPCAs have continued to improve.

Short- and Mid-Term Results of Pulmonary Valve Replacement with the Inspiris Valve.

BACKGROUND: Various bioprosthetic valves are used off-label for pulmonary valve replacement (PVR), but there is no consensus on whether a particular valve is best for this application. Recently, the Inspiris Resilia valve (Edwards Lifesciences Inc) was approved for aortic valve replacement, and surgeons have begun using it for PVR. There is limited evidence on the performance of the Inspiris valve compared with other valves in the pulmonary position. METHODS: This study reviewed all patients who underwent PVR with a size 19- to 29-mm Inspiris valve or Mosaic valve (Medtronic Inc) from 2007 to 2022 at Lucile Packard Children's Hospital Stanford (Palo Alto, CA). Midterm outcomes included freedom from moderate or severe pulmonary regurgitation (PR), a maximum Doppler gradient ≥36 mm Hg, and freedom from reintervention. RESULTS: A total of 225 consecutive patients who underwent PVR with a size 19- to 29-mm Mosaic (n = 163) or Inspiris (n = 62) valve were included. There was no difference in baseline characteristics. Early postoperative gradients were low in both groups but higher in the Mosaic cohort, and neither group had more than mild PR on discharge. On univariable and multivariable analysis, Inspiris valves were significantly more likely to develop moderate or greater PR over time. There was no significant difference between the valves in freedom from reintervention or from a maximum gradient ≥36 mm Hg. CONCLUSIONS: Early and short-term gradients were similar in patients undergoing PVR with Inspiris and Mosaic valves, but significant PR was more common in patients who received an Inspiris valve. These preliminary findings suggest that the durability of the Inspiris valve in the pulmonary position may not be superior to that of other bioprosthetic valves used for PVR.

A Deep Dive Into Retroesophageal Major Aortopulmonary Collateral Arteries.

Background: The anatomy of major aortopulmonary collateral arteries (MAPCAs) can be highly variable with regard to number, anatomic origin, course, and relationship to the native pulmonary arteries. Some MAPCAs travel behind the esophagus (retroesophageal) and bronchus before entering the lung parenchyma. The purpose of this paper was to review the anatomy, physiology, and surgical characteristics of retroesophageal MAPCAs. Methods: This manuscript summarizes the data from a series of three papers that have focused on the subject of retroesophageal MAPCAs from our institution over the past ten years. Results: Two-thirds of patients evaluated had a retroesophageal MAPCA identified at surgery. Retroesophageal major aortopulmonary collateral arteries (REMs) were more common with a left arch (77%) compared with a right arch (53%). Of all REMs evaluated, 83% were single supply, 13% were dual supply with an inadequate connection, and 4% were dual supply with an adequate connection. Based on these findings, 96% of retroesophageal MAPCAs were unifocalized. Follow-up catheterization was performed at a median of 17 months after surgery; 75% of unifocalized MAPCAs were widely patent, 20% were patent but stenotic, and 5% were occluded. Conclusions: The data demonstrate that retroesophageal MAPCAs are relatively common and almost always require unifocalization. At mid-term follow-up, 95% of unifocalized MAPCAs were found to be patent.

Outcomes After Development of Ventricular Arrhythmias in Single Ventricular Heart Disease Patients With Fontan Palliation.

BACKGROUND: With the advent of more intensive rhythm monitoring strategies, ventricular arrhythmias (VAs) are increasingly detected in Fontan patients. However, the prognostic implications of VA are poorly understood. We assessed the incidence of VA in Fontan patients and the implications on transplant-free survival. METHODS: Medical records of Fontan patients seen at a single center between 2002 and 2019 were reviewed to identify post-Fontan VA (nonsustained ventricular tachycardia >4 beats or sustained >30 seconds). Patients with preFontan VA were excluded. Hemodynamically unstable VA was defined as malignant VA. The primary outcome was death and heart transplantation. Death with censoring at transplant was a secondary outcome. RESULTS: Of 431 Fontan patients, transplant-free survival was 82% at 15 years post-Fontan with 64 (15%) meeting primary outcome of either death (n=16, 3.7%), at a median 4.6 (0.4-10.2) years post-Fontan, or transplant (n=48, 11%), at a median of 11.1 (5.9-16.2) years post-Fontan. Forty-eight (11%) patients were diagnosed with VA (90% nonsustained ventricular tachycardia, 10% sustained ventricular tachycardia). Malignant VA (n=9, 2.0%) was associated with younger age, worse systolic function, and valvular regurgitation. Risk for VA increased with time from Fontan, 2.4% at 10 years to 19% at 20 years. History of Stage 1 surgery with right ventricular to pulmonary artery conduit and older age at Fontan were significant risk factors for VA. VA was strongly associated with an increased risk of transplant or death (HR, 9.2 [95% CI, 4.5-18.7]; P<0.001), with a transplant-free survival of 48% at 5-year post-VA diagnosis. CONCLUSIONS: Ventricular arrhythmias occurred in 11% of Fontan patients and was highly associated with transplant or death, with a transplant-free survival of <50% at 5-year post-VA diagnosis. Risk factors for VA included older age at Fontan and history of right ventricular to pulmonary artery conduit. A diagnosis of VA in Fontan patients should prompt increased clinical surveillance.

Analysis of risk factors associated with extracorporeal membrane oxygenation after surgical repair of peripheral pulmonary artery stenoses.

Objective: Acute lung injury is a known complication of pulmonary artery reconstruction for peripheral pulmonary artery stenosis. Severe cases may require support with extracorporeal membrane oxygenation. The purpose of this study was to evaluate the characteristics of patients requiring extracorporeal membrane oxygenation after pulmonary artery reconstruction. Methods: This was a retrospective study of 150 patients who underwent surgical repair of peripheral pulmonary artery stenosis at our institution from 2002 to 2022. Underlying diagnoses included Williams syndrome (n = 44), Alagille syndrome (n = 43), elastin arteriopathy (n = 21), tetralogy of Fallot (n = 21), and other (n = 21). Characteristics of patients who required extracorporeal membrane oxygenation were compared with those who did not require extracorporeal membrane oxygenation. Results: Eleven of the 150 patients undergoing pulmonary artery reconstruction (7.3%) required postoperative extracorporeal membrane oxygenation support (10 for acute lung injury and 1 for cardiac insufficiency). Four patients receiving extracorporeal membrane oxygenation had Williams syndrome, 3 patients had Alagille, and 4 patients had tetralogy of Fallot. Patients requiring extracorporeal membrane oxygenation had a higher preoperative right ventricle to aortic peak systolic pressure ratios (mean 1.14 vs 0.95), greater number of pulmonary artery ostial interventions (median, 23 vs 17), and longer duration of cardiopulmonary bypass (median, 597 vs 400 minutes). There were 3 in-hospital deaths (2.0%), 2 of whom required postoperative extracorporeal membrane oxygenation support. Conclusions: The data demonstrate multiple differences between patients who did and did not require extracorporeal membrane oxygenation after surgical repair of peripheral pulmonary artery stenosis. These results suggest that the preoperative extent of disease may predispose to the development of acute lung injury requiring extracorporeal membrane oxygenation support.

Serial Lung Perfusion Scintigraphy After Unifocalization and Repair of Tetralogy of Fallot With Major Aortopulmonary Collaterals.

BACKGROUND: In patients with tetralogy of Fallot and major aortopulmonary collaterals (MAPCAs), pulmonary blood supply is highly variable. Our approach to this condition emphasizes complete unifocalization of the pulmonary circulation, incorporating all lung segments and addressing stenoses out to the segmental level. Post-repair, we recommend serial lung perfusion scintigraphy (LPS) to assess short-term changes in pulmonary blood flow distribution. METHODS: We reviewed post-discharge and follow-up LPS performed through three years post-repair and analyzed serial changes in perfusion, risk factors for change, and the relationship between LPS parameters and pulmonary artery reintervention. RESULTS: Of 543 patients who had postoperative LPS results in our system, 317 (58%) had only a predischarge LPS available for review, while 226 had 1 (20%) or more (22%) follow-up scans within three years. Overall, pulmonary flow distribution prior to discharge was balanced, and there was minimal change over time; however, there was considerable patient-to-patient variation in both metrics. On multivariable mixed modeling, time after repair (P = .025), initial anatomy consisting of a ductus arteriosus to one lung (P < .001), and age at repair (P = .014) were associated with changes on serial LPS. Patients who had follow-up LPS were more likely to undergo pulmonary artery reintervention, but within that cohort, LPS parameters were not associated with reintervention risk. CONCLUSION: Serial LPS during the first year after MAPCAs repair is a noninvasive method of screening for significant post-repair pulmonary artery stenosis that occurs in a small but important minority of patients. In patients who received follow-up LPS beyond the perioperative period, there was minimal change over time in the population overall, but large changes in some patients and considerable variability. There was no statistical association between LPS findings and pulmonary artery reintervention.

Williams Syndrome: Supravalvar Aortic, Aortic Arch, Coronary and Pulmonary Arteries: Is Comprehensive Repair Advisable and Achievable?

Williams syndrome, and various elastin protein mediated arteriopathies, presents a clinical challenge to pediatric cardiovascular specialists. In the severest phenotypes, multilevel obstruction to the systemic and pulmonic arterial systems result in biventricular dysfunction which can be imminently life-threatening. As a longstanding, quaternary referral center for complex pulmonary arteriopathies and pediatric connective tissue disease, Stanford Medicine Children's Health has developed a sizeable experience managing these patients. This manuscript is a summary of our current strategies, with a focus on our surgical techniques, peri-procedural considerations on timing and staging of various interventions, and long-term results.

Surgical repair of peripheral pulmonary artery stenosis: A 2-decade experience with 145 patients.

BACKGROUND: Peripheral pulmonary artery stenosis (PPAS) is a relatively rare form of congenital heart disease often associated with Williams syndrome, Alagille syndrome, and elastin arteriopathy. This disease is characterized by stenoses at nearly all lobar and segmental ostia and results in systemic-level right ventricular pressures. The current study summarizes our experience with the surgical treatment of PPAS. METHODS: This was a retrospective review of 145 patients who underwent surgical repair of PPAS. This included 43 patients with Williams syndrome, 39 with Alagille syndrome, and 21 with elastin arteriopathy. Other diagnoses include tetralogy of Fallot with PPAS (n = 21), truncus arteriosus (n = 5), transposition (n = 3), double-outlet right ventricle (n = 2), arterial tortuosity syndrome (n = 3), and other (n = 8). RESULTS: The median preoperative right ventricle to aortic peak systolic pressure ratio was 1.01 (range, 0.50-1.60) which was reduced to 0.30 (range, 0.17-0.60) postoperatively. The median number of ostial repairs was 17 (range, 6-34) and median duration of cardiopulmonary bypass was 398 minutes (range, 92-844). There were 3 in-hospital deaths (2.1%). The median duration of follow-up was 26 months (range, 1-220) with 4 late deaths (2.9%). Eighty-two patients have subsequently undergone catheterization and 74 had a pressure ratio <0.50. CONCLUSIONS: The surgical treatment of PPAS resulted in a 70% reduction in right ventricular pressures. At 3 years, freedom from death was 94% and 90% of those evaluated maintained low pressures. These results suggest that the surgical treatment of PPAS is highly effective in most patients.

The development and efficacy of a paediatric cardiology fellowship online preparatory course.

BACKGROUND: The transition from residency to paediatric cardiology fellowship is challenging due to the new knowledge and technical skills required. Online learning can be an effective didactic modality that can be widely accessed by trainees. We sought to evaluate the effectiveness of a paediatric cardiology Fellowship Online Preparatory Course prior to the start of fellowship. METHODS: The Online Preparatory Course contained 18 online learning modules covering basic concepts in anatomy, auscultation, echocardiography, catheterisation, cardiovascular intensive care, electrophysiology, pulmonary hypertension, heart failure, and cardiac surgery. Each online learning module included an instructional video with pre-and post-video tests. Participants completed pre- and post-Online Preparatory Course knowledge-based exams and surveys. Pre- and post-Online Preparatory Course survey and knowledge-based examination results were compared via Wilcoxon sign and paired t-tests. RESULTS: 151 incoming paediatric cardiology fellows from programmes across the USA participated in the 3 months prior to starting fellowship training between 2017 and 2019. There was significant improvement between pre- and post-video test scores for all 18 online learning modules. There was also significant improvement between pre- and post-Online Preparatory Course exam scores (PRE 43.6 ± 11% versus POST 60.3 ± 10%, p < 0.001). Comparing pre- and post-Online Preparatory Course surveys, there was a statistically significant improvement in the participants' comfort level in 35 of 36 (97%) assessment areas. Nearly all participants (98%) agreed or strongly agreed that the Online Preparatory Course was a valuable learning experience and helped alleviate some anxieties (77% agreed or strongly agreed) related to starting fellowship. CONCLUSION: An Online Preparatory Course prior to starting fellowship can provide a foundation of knowledge, decrease anxiety, and serve as an effective educational springboard for paediatric cardiology fellows.

Impact of liver dysfunction on outcomes in children with Alagille syndrome undergoing congenital heart surgery.

OBJECTIVES: Children with Alagille syndrome often have complex forms of congenital heart defects with the majority having peripheral pulmonary artery stenosis (PPAS) and pulmonary valve atresia (PA) or pulmonary valve stenosis. Children with Alagille syndrome also have variable amounts of liver dysfunction. The purpose of this study was to evaluate the impact of liver dysfunction on outcomes in children with Alagille syndrome undergoing congenital heart surgery. METHODS: This was a retrospective review of 69 patients with Alagille syndrome who underwent congenital heart surgery at our institution. The underlying diagnoses included PPAS (n = 29), tetralogy of Fallot with PPAS (n = 14), tetralogy with PA (n = 3), PA with ventricular septal defect and major aortopulmonary collateral arteries (n = 21) and one each with D-transposition and supravalvar aortic stenosis. RESULTS: The median age at surgery was 16 months (range 0-228 months). Procedures performed included PPAS repair (n = 43), tetralogy with PA repair (n = 3), unifocalization procedures (n = 21) and other (n = 2). Forty-two (61%) patients had mild or no liver dysfunction, while 26 (38%) had moderate or severe liver dysfunction. The median cardiopulmonary bypass time was 345 min (341 with liver dysfunction, 345 without liver dysfunction). There were a total of 8 operative (12%) deaths and 3 late (4%) deaths. Six operative and 2 late deaths occurred in patients with liver dysfunction (combined 30.7%) versus 2 operative and 1 late death (combined 7.1%) for patients without liver dysfunction (P < 0.05). CONCLUSIONS: These results suggest that liver dysfunction has a profound impact on survival in children with Alagille syndrome undergoing congenital heart surgery.

Innominate artery patency after direct cannulation in neonates.

Objective: The study objective was to determine the short-term incidence of innominate artery stenosis for neonates who underwent direct innominate artery cannulation during the Norwood procedure. Methods: This is a retrospective, single-institution review of 92 patients who underwent the Norwood procedure with direct innominate artery cannulation from 2006 to 2017. The primary outcome was angiographic evidence of patency at pre-Glenn cardiac catheterization. Patient characteristics, intraoperative surgical and hemodynamic measurements, and postoperative neurologic findings were recorded. Results: At a median age of 5.0 days, 92 neonates underwent the Norwood procedure with direct innominate artery cannulation. These patients underwent cardiac catheterization at a median of 3.0 months after the index operation. In 5 of 92 patients with catheterization images available for review, there was angiographic evidence of mild innominate artery stenosis, and none had moderate or severe stenosis. Review of follow-up records did not reveal evidence of clinically significant stenosis or innominate artery reintervention. Conclusions: In neonates undergoing the Norwood procedure with direct innominate cannulation, innominate artery stenosis was uncommon and clinically significant stenosis did not occur.

The number of postoperative surgical or diagnostic procedures following congenital heart surgery correlates with both mortality and hospital length of stay.

BACKGROUND: Outcomes for congenital heart disease have dramatically improved over the past several decades. However, there are patients who encounter intraoperative or postoperative complications and ultimately do not survive. It was our hypothesis that the number of postoperative procedures (including surgical and unplanned diagnostic procedures) would correlate with hospital length of stay and operative mortality. METHODS: This was a retrospective review of 938 consecutive patients undergoing congenital heart surgery at a single institution over a 2-year timeframe. The number of postoperative surgical and unplanned diagnostic procedures were counted and the impact on hospital length of stay and mortality was assessed. RESULTS: 581 of the 938 (62%) patients had zero postoperative diagnostic or surgical procedures. These patients had a median length of stay of 6 days with a single operative mortality (0.2%). 357 of the 938 (38%) patients had one or more postoperative diagnostic or surgical procedures. These patients had a total of 1586 postoperative procedures. There was a significant correlation between the number of postoperative procedures and both hospital length of stay and mortality (p < .001). Patients who required 10 or more postoperative procedures had a median hospital length of stay of 89 days and had a 50% mortality. There were no survivors in patients who had 15 or more postoperative procedures. CONCLUSIONS: The data demonstrate that the number of postoperative procedures was highly correlated with both hospital length of stay and mortality.

Proton magnetic resonance spectroscopy assessment of neonatal brain metabolism during cardiopulmonary bypass surgery.

Here, we report on the development and performance of a robust 3-T single-voxel proton magnetic resonance spectroscopy (1 H MRS) experimental protocol and data analysis pipeline for quantifying brain metabolism during cardiopulmonary bypass (CPB) surgery in a neonatal porcine model, with the overall goal of elucidating primary mechanisms of brain injury associated with these procedures. The specific aims were to assess which metabolic processes can be reliably interrogated by 1 H MRS on a 3-T clinical scanner and to provide an initial assessment of brain metabolism during deep hypothermia cardiac arrest (DHCA) surgery and recovery. Fourteen neonatal pigs underwent CPB surgery while placed in a 3-T MRI scanner for 18, 28, and 37°C DHCA studies under hyperglycemic, euglycemic, and hypoglycemic conditions. Total imaging times, including baseline measurements, circulatory arrest (CA), and recovery averaged 3 h/animal, during which 30-40 single-voxel 1 H MRS spectra (sLASER pulse sequence, TR/TE = 2000/30 ms, 64 or 128 averages) were acquired from a 2.2-cc right midbrain voxel. 1 H MRS at 3 T was able to reliably quantify (1) anaerobic metabolism via depletion of brain glucose and the associated build-up of lactate during CA, (2) phosphocreatine (PCr) to creatine (Cr) conversion during CA and subsequent recovery upon reperfusion, (3) a robust increase in the glutamine-to-glutamate (Gln/Glu) ratio during the post-CA recovery period, and (4) a broadening of the water peak during CA. In vivo 1 H MRS at 3 T can reliably quantify subtle metabolic brain changes previously deemed challenging to interrogate, including brain glucose concentrations even under hypoglycemic conditions, ATP usage via the conversion of PCr to Cr, and differential changes in Glu and Gln. Observed metabolic changes during CPB surgery of a neonatal porcine model provide new insights into possible mechanisms for prevention of neuronal injury.

Surgical Repair of Supravalvar Aortic Stenosis in Association With Transverse and Proximal Descending Aortic Abnormalities.

BACKGROUND: Supravalvar aortic stenosis (SVAS) may be an isolated defect of the proximal ascending aorta. However, more severe cases have extension of the arteriopathy into the transverse and proximal descending aorta. The purpose of this study was to review our experience with SVAS with and without aortic arch arteriopathy. METHODS: This was a retrospective review of 58 patients who underwent surgical repair of SVAS. The median age at repair was 18 months. A total of 37 patients had Williams syndrome. A total of 31 (53%) patients had associated peripheral pulmonary artery stenosis and 23 (39%) had coronary artery ostial stenosis (CAOS). RESULTS: A total of 37 of 58 (64%) patients had surgical repair of SVAS without the need for arch intervention while 21 (36%) patients had repair of the distal aortic arch. There were 3 (5.2%) operative deaths, 2 of whom had aortic arch involvement and one without arch involvement. There were 2 deaths after discharge from the hospital. Patients who needed arch surgery were more likely to have severe arch gradients compared to those without arch involvement (71% vs 30%, P < .05), were more likely to undergo concomitant procedures for peripheral pulmonary artery stenosis or CAOS (90% vs 62%, P < .05), and to have Williams syndrome (86% vs 51%, P < .05). CONCLUSIONS: More than one-third of patients who had SVAS repair at our institution had procedures directed at the transverse or proximal descending aorta. Patients with arch involvement had more severe arch obstruction, required more concomitant procedures, and were more likely to have Williams syndrome.

Airway Characteristics of Patients With 22q11 Deletion Undergoing Pulmonary Artery Reconstruction Surgery: Retrospective Cohort Study.

OBJECTIVES: We have previously shown that patients with a chromosome 22q11 microdeletion are at risk for prolonged respiratory failure after pulmonary artery reconstruction surgery compared with those with normal genotype. We sought to describe preexisting airway abnormalities in this patient population and examine relationships between airway abnormalities and outcomes. DESIGN: Single-center retrospective chart review from Society of Thoracic Surgery and Pediatric Cardiac Critical Care Consortium databases and the electronic medical record. SETTING: Lucile Packard Children's Hospital at Stanford from September 2017 to February 2019. PATIENTS: All patients undergoing pulmonary artery reconstruction surgery were considered for inclusion. INTERVENTIONS: We identified 127 patients meeting study inclusion criteria. Thirty-nine patients met specific criteria and underwent screening preoperative bronchoscopy including microdirect laryngoscopy and lower airway examination. Postoperative bronchoscopy was performed at the discretion of the intensive care team. MEASUREMENTS AND MAIN RESULTS: Airway abnormalities were detected in 25/26 of children (96%) with a chromosome 22q11 deletion who underwent preoperative bronchoscopy. Upper and lower airway pathologies were found in 19/25 (73%) and 21/25 (81%) patients, respectively, and it was common for patients to have more than one abnormality. Presence of 22q11 deletion was associated with longer duration of mechanical ventilation (9.1 vs 4.3 d; p = 0.001), use of noninvasive positive pressure support (13 vs 6 d; p = 0.001), and longer hospital stays (30 vs 14 d; p = 0.002). These outcomes were worse when compared with patients with known airway abnormalities who did not have 22q11 deletion. CONCLUSIONS: Preexisting upper and lower airway pathologies are common in patients with a chromosome 22q11 deletion who undergo pulmonary artery reconstruction surgery. Despite similar postoperative hemodynamics and outcomes as their counterparts without 22q11 deletion, 22q11 deletion is associated with more postoperative respiratory complications not entirely explained by preexisting airway abnormalities.

Reevaluating Congenital Heart Surgery Center Performance Using Operative Mortality.

BACKGROUND: The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) provides observed-to-expected (O/E) operative mortality ratios to more than 100 congenital heart centers in North America. We compared the current approach for estimating O/E ratios to approaches incorporating information on diagnosis as moderators of procedures, other unused risk factors, and additional variation in confidence interval construction to characterize center performance. METHODS: Bayesian additive regression trees (BART) and lasso models linked operative mortality to diagnosis-procedure categories, procedure-specific risk factors, and syndromes/abnormalities. Bootstrapping accounted for variation in the STS-CHSD (STS bootstrap) and lasso CIs. We compared O/E estimates, interquartile range of CI widths, and concordance of center performance categorizations (worse-than-, as-, or better-than-expected mortality) of the new approaches to the STS-CHSD. RESULTS: In 110 surgical centers including 98,822 surgical operative encounters, there were 2818 (2.85%) operative mortalities (center range, 0.37%-10%). Compared with the STS-CHSD, BART- and lasso-estimated O/E ratios varied more and had narrower confidence intervals (interquartile range of confidence interval: STS-CHSD = 1.11, STS bootstrap = 0.98; lasso = 0.80; BART = 0.96). Concordance of performance categorization with the STS-CHSD ranged from 84% (lasso) to 91% (STS Bootstrap); more than 70% of discordant centers improved categories. Discordant centers had smaller volumes, fewer operative mortalities, and treated more patients with congenital lung abnormalities. CONCLUSIONS: Relative to the STS-CHSD, up to 16% of hospitals changed performance categories, most improving performance. Given the significance of quality reports for congenital heart centers, inclusion of additional risk factors and unaddressed variation should be considered.

Mortality Prediction After Cardiac Surgery in Children: An STS Congenital Heart Surgery Database Analysis.

BACKGROUND: The Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (CHSD) provides risk-adjusted operative mortality rates to approximately 120 North American congenital heart centers. Optimal case-mix adjustment methods for operative mortality risk prediction in this population remain unclear. METHODS: A panel created diagnosis-procedure combinations of encounters in the CHSD. Models for operative mortality using the new diagnosis-procedure categories, procedure-specific risk factors, and syndromes or abnormalities included in the CHSD were estimated using Bayesian additive regression trees and least absolute shrinkage and selector operator (lasso) models. Performance of the new models was compared with the current STS CHSD risk model. RESULTS: Of 98 825 operative encounters (69 063 training; 29 762 testing), 2818 (2.85%) STS-defined operative mortalities were observed. Differences in sensitivity, specificity, and true and false positive predicted values were negligible across models. Calibration for mortality predictions at the higher end of risk from the lasso and Bayesian additive regression trees models was better than predictions from the STS CHSD model, likely because of the new models' inclusion of diagnosis-palliative procedure variables affecting <1% of patients overall but accounting for 27% of mortalities. Model discrimination varied across models for high-risk procedures, hospital volume, and hospitals. CONCLUSIONS: Overall performance of the new models did not differ meaningfully from the STS CHSD risk model. Adding procedure-specific risk factors and allowing diagnosis to modify predicted risk for palliative operations may augment model performance for very high-risk surgical procedures. Given the importance of risk adjustment in estimating hospital quality, a comparative assessment of surgical program quality evaluations using the different models is warranted.