Complete atrioventricular septal defect with absent or diminutive primum component: Incidence, anatomic characteristics, and outcomes.

BACKGROUND: Repair of complete atrioventricular septal defect with absent or diminutive primum defect is challenging because of atrial septal malposition and abnormal anatomy of the left atrioventricular valve. We sought to define the incidence, anatomy, and surgical outcomes of this entity. METHODS: We identified all patients in our institutional database presenting for complete atrioventricular septal defect repair from 2006 to 2018. Operative reports and echocardiograms were reviewed to determine the presence and size of the primum defect, atrioventricular valve anatomy, degree of atrioventricular valve regurgitation, repair method, and complications, including reoperation for atrioventricular valve regurgitation. Functionally univentricular patients and those receiving repair at an outside institution were excluded. RESULTS: Of 183 patients with complete atrioventricular septal defect, absent/diminutive primum defect occurred in 16 patients (8.7%; 10 absent, 6 diminutive). Six patients (38%) had leftward malposition of the atrium septum on the common atrioventricular valve. The rate of reoperation for left atrioventricular valve regurgitation was 31% (3 early, 2 late), for which preoperative predictors included leftward malposition of the atrial septum onto the common atrioventricular valve (4/6 patients with malposition required reoperation, P = .036, Fisher exact test). One patient exhibiting this risk factor died. The overall rate of moderate or greater left atrioventricular valve regurgitation on the most recent postoperative echocardiogram was 13% (2/16 patients; median follow-up, 141 days; range, 3-2236 days). CONCLUSIONS: Complete atrioventricular septal defect with absent or diminutive primum defect is a unique variant of complete atrioventricular septal defect for which the risk of reoperation for left atrioventricular valve regurgitation after complete repair is high and risk factors include leftward malposition of the atrial septum on the common atrioventricular valve.

Neonatal venoarterial extracorporeal membrane oxygenation cannulation technique.

Peripheral cannulation for initiation of neonatal venoarterial extracorporeal membrane oxygenation is an essential technical skill in the armamentarium of every congenital cardiac surgeon and is necessary for the care of newborns with congenital heart disease and other conditions presenting with cardiopulmonary failure. With certain exceptions, it is usually performed via a right neck cut-down to expose the right internal jugular vein and common carotid artery.   A strong understanding of the fundamental techniques, as well as strategies for avoiding common pitfalls, is critical to the success of cardiopulmonary rescue afforded by cannulation, especially considering the emergent conditions under which cannulation must usually be performed. We review here the operative approach and technique for neck cannulation for peripheral neonatal venoarterial extracorporeal membrane oxygenation.

Serum Protein Changes in Pediatric Sepsis Patients Identified With an Aptamer-Based Multiplexed Proteomic Approach.

OBJECTIVES: Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response to infection, is a leading cause of death and disability among children worldwide. Identifying sepsis in pediatric patients is difficult and can lead to treatment delay. Our objective was to assess the host proteomic response to infection utilizing an aptamer-based multiplexed proteomics approach to identify novel serum protein changes that might help distinguish between pediatric sepsis and infection-negative systemic inflammation and hence can potentially improve sensitivity and specificity of the diagnosis of sepsis over current clinical criteria approaches. DESIGN: Retrospective, observational cohort study. SETTING: PICU and cardiac ICU, Seattle Children's Hospital, Seattle, WA. PATIENTS: A cohort of 40 children with clinically overt sepsis and 30 children immediately postcardiopulmonary bypass surgery (infection-negative systemic inflammation control subjects) was recruited. Children with sepsis had a confirmed or suspected infection, two or more systemic inflammatory response syndrome criteria, and at least cardiovascular and/or pulmonary organ dysfunction. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Serum samples from 35 of the sepsis and 28 of the bypass surgery subjects were available for screening with an aptamer-based proteomic platform that measures 1,305 proteins to search for large-scale serum protein expression pattern changes in sepsis. A total of 111 proteins were significantly differentially expressed between the sepsis and control groups, using the linear models for microarray data (linear modeling) and Boruta (decision trees) R packages, with 55 being previously identified in sepsis patients. Weighted gene correlation network analysis helped identify 76 proteins that correlated highly with clinical sepsis traits, 27 of which had not been previously reported in sepsis. CONCLUSIONS: The serum protein changes identified with the aptamer-based multiplexed proteomics approach used in this study can be useful to distinguish between sepsis and noninfectious systemic inflammation.

Hybrid stage 1 palliation as a bridge to cardiac transplantation in patients with high-risk single ventricle physiology.

BACKGROUND: The hybrid stage 1 palliation for hypoplastic left heart syndrome (HLHS) was first described in 1993 as a bridge to heart transplant for HLHS. There are limited data on this strategy as primary heart transplantation for HLHS has become less common. METHODS: This is an observational, single-center study comparing pre- and post-transplant outcomes of patients listed for transplant following hybrid palliation with those following surgical stage 1 palliation. RESULTS: From 2004 to 2017, 21 patients underwent hybrid palliation as a bridge to heart transplant and 28 patients were listed for transplant following surgical stage 1 palliation or aortic arch repair and pulmonary artery band placement. Premature birth and the presence of genetic or anatomic abnormalities were more common in the hybrid group. Need for extracorporeal membrane oxygenation (ECMO) support and ventricular dysfunction was more common in the surgical group. There was a trend toward shorter waitlist times in the surgical cohort (36 days vs 70 days, P = 0.06). There was no difference in waitlist mortality (19% vs 21%, P = 0.61). Survival at 1 and 5 years post-transplant was similar for the hybrid and surgical cohorts (5-year survival, 80% vs 85%, P = 0.94, respectively). There was no difference in the number of post-transplant interventions. CONCLUSIONS: Although the hybrid patients represented a higher risk cohort and demonstrated longer wait times, the waitlist and post-transplant mortality was equivalent between the two groups. For high-risk patients, the hybrid palliation as a bridge to transplant appears to be a reasonable strategy.

A tale of two cases of pulmonary arteriovenous malformation: How they fared after cardiac transplantation.

BACKGROUND: In single ventricle patients, aortopulmonary collaterals (APCs) and pulmonary arteriovenous malformations (PAVMs) following superior cavopulmonary shunt (CPS) can complicate orthotopic heart transplant (OHT) by cyanosis and hemoptysis. Although PAVMs can regress with the restoration of hepatic venous flow to the pulmonary circulation, the effects of hypoxemia on the "unconditioned" allograft are not known. CASES: Two patients with significant PAVMs after CPS were cyanotic following OHT. One patient with predominantly unilateral left PAVMs had arterial saturation levels less than 70% despite pulmonary vasodilators and ventilation. A custom flow restrictor-covered stent was deployed in the pulmonary artery of the affected side, redirecting the blood flow to the contralateral lung, immediately improving cyanosis. When the PAVMs regressed, the flow restrictor stent was dilated to eliminate the constriction. The second patient with PAVMs had cyanosis and severe hemoptysis from APCs post-OHT. The APCs required an extensive coil embolization, while the cyanosis responded to oxygen and pulmonary vasodilators. Both recipients did well with gradual resolution of PAVMs within 8 months. CONCLUSIONS: Despite cyanosis from right-to-left intrapulmonary shunting, allograft function recovered. Novel transcatheter interventions can play a role in patients with significant APCs or PAVM following cardiac transplantation.

Tricuspid valve replacement with a melody stented bovine jugular vein conduit.

Atrioventricular valve replacement options are limited in infants and small children. The Melody stented bovine jugular vein conduit is being used with increasing frequency for percutaneous pulmonary valve replacement. The Melody valve can be serially dilated over time to accommodate the somatic growth of pediatric patients. We report the initial experience of using the Melody valve as a surgical tricuspid valve replacement in an infant.

Significance of positive mediastinal cultures in pediatric cardiovascular surgical procedure patients undergoing delayed sternal closure.

BACKGROUND: Many pediatric cardiac surgery centers obtain mediastinal cultures at the time of delayed sternal closure (DSC). There are no recommendations regarding how to treat patients with positive cultures. We explored the clinical significance of positive mediastinal cultures with regard to surgical site infections (SSI). METHODS: A retrospective study was performed on all patients who underwent DSC at our institution between December 2006 and December 2011. National Healthcare Safety Network criteria were used to prospectively identify SSIs. Univariate and multivariate logistic regression analyses were performed to evaluate potential risk factors for SSI and predictors for positive mediastinal cultures obtained at DSC. RESULTS: A total of 178 patients underwent DSC during the study period; 155 patients met the eligibility criteria for the study and were included in the analysis. Of the 155 included patients, 11 patients (7.1%) experienced SSI. Patients with a positive mediastinal culture obtained at DSC were more likely to experience SSI than were patients with a negative culture (p=0.003). In univariate analysis, a positive mediastinal culture was the only factor associated with SSI (odds ratio [OR], 7.4; 95% confidence interval [CI], 2.1 to 26.7). In multivariate analysis, age at operation≥2 weeks (adjusted OR [aOR], 4.9; 95% CI, 1.84 to 12.8), receipt of stress-dosed hydrocortisone while the chest was open (aOR, 2.9; 95% CI, 1.1 to 7.6), and gestational age≤37 weeks (aOR, 2.7; 95% CI, 1.01 to 7.27) were independent predictors for a positive mediastinal culture. CONCLUSIONS: Patients with positive mediastinal cultures obtained at DSC had a significantly higher rate of subsequent SSI, and a positive mediastinal culture was the only statistically significant predictor of SSI.

Downsized Contegra graft as a right ventricle-to-pulmonary artery conduit in the setting of mediastinitis.

Polytetrafluoroethylene (PTFE) grafts are commonly used for construction of the right ventricle-to-pulmonary artery conduit in the modified Norwood procedure. Dehiscence of a PTFE conduit in the setting of purulent mediastinitis presents a challenging clinical problem because of limited availability of appropriately sized replacement vascular homografts. The Contegra bovine jugular vein graft is an alternative to placing another PTFE graft in an infected space when a homograft of appropriate size is not available. We describe the use of a downsized Contegra conduit to replace an infected PTFE right ventricle-to-pulmonary artery graft in a neonate with life-threatening purulent mediastinitis.

Direct optical measurement of intraoperative myocardial oxygenation during congenital heart surgery.

This study demonstrates use of novel technology to measure cellular oxygenation during corrective congenital heart surgery. Cellular oxygenation was measured using a custom-designed optical probe placed on the free wall of the right ventricle. Cellular oxygenation, determined from myoglobin saturation, was calculated using multiwavelength analysis. Timing of bypass, aortic cross-clamp, infusion of cardioplegic solution, and length of intensive care unit (ICU) stay were recorded. Baseline cellular oxygenation was approximately 50% just before aortic cross-clamp and decreased to approximately 20% during cardioplegia. Cellular oxygenation remained low throughout cardioplegia and returned toward baseline after bypass. In four cases, cellular oxygenation did not return as quickly to baseline as in the other three cases. Among the four patients demonstrating slow recovery, the average ICU length of stay was 2.25 days compared with an average stay of 1.33 days for those patients exhibiting rapid cellular oxygenation recovery (p = 0.06). The slow recovery group had an average cross-clamp time of 40.1 ± 28.4 minutes, compared with 26.0 ± 8.5 minutes for the fast recovery group (p = 0.34). This study demonstrates for the first time that myocyte cellular oxygenation can be measured intraoperatively during cardiac surgery. Measurement of cellular oxygenation may be useful for improving myocardial preservation techniques.

Minimizing bleeding associated with mechanical circulatory support following pediatric heart surgery.

OBJECTIVE: The use of extracorporeal membrane oxygenation (ECMO) to support patients with early postcardiotomy heart failure may be associated with catastrophic bleeding, making its use undesirable. However, postcardiotomy mechanical circulatory assistance is necessary in some patients to allow for myocardial recovery. We have assembled a centrifugal pump system (CPS) that does not require early systemic anticoagulation. This study compares postoperative bleeding in pediatric patients placed on standard ECMO versus CPS within 24h of cardiotomy. METHODS: Between November 2002 and February 2007, 25 patients (age 0 days-1.72 years) received postcardiotomy mechanical support. Fourteen patients were placed on ECMO and 11 patients were placed on CPS within 24h of surgical repair. Retrospective analysis was performed of chest-tube drainage at multiple time points following initiation of mechanical support. Additional variables, including Risk Adjustment for Congenital Heart Surgery-1 (RACHS-1) score, total time on mechanical support, 30-day mortality, activated clotting time, blood-product administration, circuit-related complications, and circuit changes were also analyzed. RESULTS: Patients on ECMO (0.30 ± 0.39 years) and CPS (0.40 ± 0.56 years) were of similar age (p = 0.64). Patients on ECMO (0.3 ± 0.1m(2)) and CPS (0.3 ± 0.1m(2)) had similar body surface areas (p = 0.46). Patients placed on CPS had significantly less chest-tube drainage during the first 4h of support. Activated clotting times appeared to be higher during the first 12h of ECMO versus CPS. There was no statistical difference between ECMO and CPS with respect to the following variables: RACHS-1 score, time on support, 30-day mortality, circuit-related complications, and circuit changes. Blood-product administration at 24h of support was significantly less (p = 0.04) for patients on CPS versus ECMO. CONCLUSIONS: Mechanical circulatory support can be provided without the complication of clinically significant bleeding if a specialized circuit is used. This has important implications for the decision to use mechanical support in the immediate postoperative period in the face of ventricular failure. In addition, early mechanical support can be used with a low incidence of circuit-related complications.

Association of thymectomy with infection following congenital heart surgery.

BACKGROUND: Congenital absence of the thymus can lead to profound immunodeficiency, suggesting that thymic function during fetal development is essential to normal lymphocyte development. How vital the thymus after birth is to human immune competence and regulation is not known. Routine thymectomy, especially at an early age, may influence immunity, and therefore the risk of infection, autoimmunity, or malignancy. METHODS: A retrospective review of cardiac surgery patients followed at Seattle Children's Hospital was performed. The primary outcome was rate of serious infections requiring hospitalization. Secondary analyses included age, type of infection, cardiac diagnosis, surgical procedure, and comorbidities. RESULTS: Patients fell into 2 groups: 60 with complete thymectomy and 35 with partial or no thymectomy. There was no statistical difference between groups in the overall prevalence of serious infections (16.7% vs 17.2%, P = 1.0). There was a nonsignificant trend toward reduced time between surgery and onset of first infection in patients in the total thymectomy group versus those without thymectomy (1.7 years vs 4.6 years, P = .07). Total thymectomy before 6 months of age also tended to increase infection rate, but the effect was not significant (0.09/year vs 0.02, P = .14). Gastroesophageal reflux in patients with total thymectomy increased the risk of infection (P = .013), suggesting a cumulative effect. CONCLUSIONS: Though infections occurred frequently in the childhood cardiac surgery population, total thymectomy was not associated with increased risk of serious infection. Comorbid conditions may be more important contributing factors increasing the risk of infection in this complex and vulnerable population.

Direct microvascular repair of an infant's transected coronary artery: case report.

The authors report the direct, microvascular repair of a right coronary artery transected during reoperation fOr complications of arterial switch operation (ASO) in a 3 month-old child. This is the first documented use of direct microsurgical anastamosis in the repair of an infant's transected coronary artery. Deviation from standard coronary bypass graft repair was permitted by vessel characteristics, as well as close collaboration between plastic surgery and cardiac surgery services. Patency of repair was confirmed intraoperatively with Doppler ultrasound and through postoperative echocardiograms documenting stable right ventricular function. This case highlights the benefit of a multidisciplinary approach to an emergent clinical problem using microsurgical techniques.

Thoracoscopic pericardial window creation and thoracic duct ligation in neonates.

OBJECTIVE: We describe 2 newborn infants with persistent pericardial effusion treated with thoracoscopic pericardial window and thoracic duct ligation. METHODS: Patient 1 was a premature female newborn who presented with severe cardiac anomalies, including dextrocardia. She was treated with pulmonary artery handing and pacemaker placement for complete cardiac block. Postoperatively, she developed pericarditis with persistent symptomatic pericardial effusion. She did not improve despite pericardial drain placement. She was treated with a thoracoscopic pericardial window. Patient 2 was a newborn male who presented with cardiac tamponade secondary to congenital chylopericardium. He did not respond to pericardial drain placement or medical management with fasting, total parenteral nutrition, and octreotide. He was treated with thoracoscopic pericardial window and thoracic duct ligation. RESULTS: Patient 1 improved rapidly. The pericardial effusion disappeared. The chest tube was removed 5 days following surgery. She died 6 weeks later of a cardiac arrhythmia secondary to pacemaker failure. The pericardial effusion had resolved. Patient 2 responded to the pericardial window and thoracic duct ligation. He was discharged 10 days following the procedure. CONCLUSIONS: Thoracoscopy provides an excellent approach to the pericardium. Pericardial windows and biopsy can be safely performed with this approach. The thoracic duct can be easily identified and ligated even in small babies. Recovery can be fast with minimal postoperative discomfort. Cosmetic results are excellent and length of hospitalization is minimized.