Racial and Ethnic Variation in Pediatric Cardiac Extracorporeal Life Support Survival.

OBJECTIVES: Previous studies have suggested an association between nonwhite race and poor outcomes in small subsets of cardiac surgery patients who require extracorporeal life support. This study aims to examine the association of race/ethnicity with mortality in pediatric patients who receive extracorporeal life support for cardiac support. DESIGN: Retrospective analysis of registry data. SETTING: Prospectively collected multi-institutional registry data. SUBJECTS: Data from all North American pediatric patients in the Extracorporeal Life Support International Registry who received extracorporeal life support for cardiac support between 1998 and 2012 were analyzed. Multivariate regression models were constructed to examine the association between race/ethnicity and hospital mortality, adjusting for demographics, diagnosis, pre-extracorporeal life support care, extracorporeal life support variables, and extracorporeal life support-related complications. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 7,106 patients undergoing cardiac extracorporeal life support, the majority of patients were of white race (56.9%) with black race (16.7%), Hispanic ethnicity (15.8%), and Asian race (2.8%) comprising the other major race/ethnic groups. The mortality rate was 53.9% (n = 3,831). After adjusting for covariates, multivariate analysis identified black race (relative risk = 1.10; 95% CI, 1.04-1.16) and Hispanic ethnicity (relative risk = 1.08; 95% CI, 1.02-1.14) as independent risk factors for mortality. CONCLUSIONS: Black race and Hispanic ethnicity are independently associated with mortality in children who require cardiac extracorporeal life support.

Embryology and anatomy of intrapulmonary shunts.

Pulmonary vascular shunting poses a major clinical risk. In this brief overview, we discuss the morphological aspects of shunting vessels in the lung, their development, and the regulation of their patency.

Extracorporeal cardiopulmonary resuscitation outcomes in term and premature neonates*.

OBJECTIVE: Extracorporeal cardiopulmonary resuscitation appears to improve survival in patients with acute refractory cardiopulmonary failure. This analysis was performed to determine survival outcomes and predictors of in-hospital mortality for term and preterm neonates who received extracorporeal cardiopulmonary resuscitation. DESIGN: Retrospective review of data from the Extracorporeal Life Support Organization international registry. SETTING: Pediatric and neonatal ICUs. PATIENTS: Infants less than or equal to 30 days. INTERVENTIONS: Extracorporeal cardiopulmonary resuscitation. MEASUREMENTS AND MAIN RESULTS: Demographic, clinical, and survival data from patients who received extracorporeal cardiopulmonary resuscitation between 1998 and 2010 were analyzed to determine factors that affect in-hospital mortality. Overall survival to hospital discharge for the 641 neonates who received extracorporeal cardiopulmonary resuscitation was 39%. In univariate analysis, gestational age correlated inversely with stroke (odds ratio, 0.84 [95% CI, 0.75-0.95]; p = 0.006) and death (odds ratio, 0.87 [95% CI, 0.78-0.96]; p = 0.005) as did corrected gestational age (odds ratio, 0.89 [95% CI, 0.81-0.97]; p = 0.006) and birth weight (odds ratio, 0.53 [95% CI, 0.38-0.74]; p < 0.001). Dysrhythmia as the primary diagnosis had significantly lower odds of death than single-ventricle cardiac disease (odds ratio, 0.24 [95% CI, 0.06-0.95]; p = 0.04). Higher pre-extracorporeal cardiopulmonary resuscitation oxygenation decreased the odds of death (odds ratio, 0.996 [95% CI, 0.994-0.999]; p = 0.01), whereas complications occurring on extracorporeal life support increased the odds of death. In the multivariate analysis, lower birth weight and pre-extracorporeal cardiopulmonary resuscitation oxygenation, as well as complications including CNS hemorrhage, pulmonary hemorrhage, acidosis, renal replacement therapy, and mechanical complications, increased the odds of death. CONCLUSIONS: Overall survival for neonates receiving extracorporeal cardiopulmonary resuscitation is similar to older pediatric patients but decreases with lower gestational age and weight. Despite this, many low-birth weight neonates survive to hospital discharge.

Continuous renal replacement therapy with an automated monitor is superior to a free-flow system during extracorporeal life support.

OBJECTIVES: To determine whether integrated continuous renal replacement therapy provides more accurate fluid management than IV pump free-flow ultrafiltration in pediatric patients on extracorporeal life support. DESIGN: Retrospective study. SETTING: PICU and neonatal ICU in a tertiary academic center. PATIENTS: Infants and children less than 18 years old. INTERVENTIONS: Extracorporeal membrane oxygenation and continuous renal replacement therapy. MEASUREMENTS AND MAIN RESULTS: Clinical data collected on patients who received free-flow or integrated renal replacement therapy while on extracorporeal life support. Normalized ultrafiltration error was calculated as: (physician specified fluid loss per 24-hr period - actual fluid loss per 24-hr period) divided by patient body weight (kg). Mixed linear regression analyses were used to model longitudinal ultrafiltration error trajectories within each mode of ultrafiltration. Based on an analysis of 458 serial ultrafiltration fluid balance measurements, integrated ultrafiltration was significantly more accurate than free-flow ultrafiltration (normalized ultrafiltration error of 1.2 vs 13.1 mL; p < 0.001). After adjusting for patient factors and time, integrated ultrafiltration was associated with a significantly lower normalized ultrafiltration error (variable estimate, -24 ± 6; p < 0.001). The use of integrated ultrafiltration was associated with shorter duration of extracorporeal life support (384 vs 583 hr, p < 0.001) and renal replacement therapy (185 vs 477 hr, p < 0.001) than free-flow patients. Overall ICU and hospital length of stay and in-hospital mortality were similar between the groups. CONCLUSIONS: While free-flow ultrafiltration has the advantages of simplicity and low cost, integrated renal replacement therapy provides more accurate fluid management during extracorporeal life support. Better fluid status management with integrated renal replacement therapy may contribute to shorter duration of extracorporeal life support.

Risk of extracorporeal life support circuit-related hyperkalemia is reduced by prebypass ultrafiltration.

OBJECTIVES: Pediatric patients who receive large volume blood transfusions are at risk for experiencing transfusion-related hyperkalemic cardiac arrest. Prebypass ultrafiltration of blood used to prime cardiopulmonary bypass circuits is commonly used in pediatric cardiac surgery to create a more physiologic and electrolyte balanced priming solution prior to initiation of cardiopulmonary bypass. This study was undertaken to determine the efficacy of prebypass ultrafiltration in normalizing extracorporeal life support circuit priming solution before initiating extracorporeal life support. DESIGN: Prospective study. SETTING: PICU and neonatal ICU in a tertiary academic center. PATIENTS: Patients requiring venovenous extracorporeal life support. INTERVENTIONS: Prebypass ultrafiltration of extracorporeal life support circuits. MEASUREMENTS AND MAIN RESULTS: Hematocrit, electrolyte, and lactate concentrations were measured in blood-primed extracorporeal life support circuits before and after ultrafiltration and in blood collected from patients before and after initiation of extracorporeal life support. Clinically significant elevation of K concentration was observed in all extracorporeal life support circuits prior to prebypass ultrafiltration, despite the fact that 93% of red blood cell units were collected ≤ 7 days prior to use. Prebypass ultrafiltration significantly reduced concentrations of K (10.9 vs 6.0 mEq/L, p = 0.001) and lactate (7.0 vs 3.6 mmol/L, p < 0.001) and increased hematocrit (37% vs 48%, p < 0.001) and concentrations of ionized calcium (0.64 vs 1.16 mg/dL, p < 0.001) and Na (129 vs 144 mEq/L, p < 0.001). Serum electrolyte concentrations remained within the normal physiologic range in all patients following initiation of venovenous extracorporeal life support with circuits that underwent prebypass ultrafiltration. CONCLUSIONS: Prebypass ultrafiltration normalizes the electrolyte balance of blood-primed extracorporeal life support circuits. Prebypass ultrafiltration processing may reduce the risk of transfusion-related hyperkalemic cardiac arrest in small children who require venovenous extracorporeal life support.

Predictors of ECMO support in infants with tachycardia-induced cardiomyopathy.

The development of tachycardia-induced cardiomyopathy (TIC) is related to the rate and duration of supraventricular tachycardia (SVT). Infants may be more susceptible to TIC because early symptoms might be unrecognized. Extracorporeal membrane oxygenation (ECMO) may improve outcome in patients with SVT and TIC; however, clinical predictors of infants who require ECMO support have not been determined. The purpose of this study was to identify predictors of the need for ECMO in infants with SVT and TIC. Sixteen infants <6 months of age who experienced resolution of TIC following control of arrhythmia were identified. Three patients (19%) required ECMO support. Comparisons were made between patients who required ECMO and those who did not. The groups were similar with respect to age at presentation, type of SVT, rate of SVT, and degree of ventricular dysfunction. However, patients requiring ECMO had increased median M-mode-derived left ventricular end diastolic dimension (LVED) z-score when compared to the medically managed patents (+2.8 vs. 0.0, P = 0.009). No patient in the medically managed group had an LVED z-score >2.3. Infants presenting with SVT and TIC with LVED z-score >2 are at increased risk for requiring ECMO support and early use of ECMO should be considered.

Outcomes of Adults with Congenital Heart Disease Supported with Extracorporeal Life Support After Cardiac Surgery.

Patients with adult congenital heart disease (ACHD) who undergo cardiac surgery may require extracorporeal life support (ECLS) for cardiopulmonary support, but outcomes after ECLS support have not been well described. This study aimed to identify risk factors for ECLS mortality in this population. We identified 368 ACHD patients who received ECLS after cardiac surgery between 1994 and 2016 in the Extracorporeal Life Support Organization (ELSO) database, a multicenter international registry of ECLS centers. Risk factors for mortality were assessed using multivariate logistic regression. Overall mortality was 61%. In a multivariate model using precannulation characteristics, Fontan physiology (odds ratio [OR]: 5.7; 95% CI: 1.6-20.0), weight over 100 kg (OR: 2.6; 95% CI: 1.3-5.4), female gender (OR: 1.6; 95% CI: 1.001-2.6), delayed ECLS cannulation (OR: 2.0; 95% CI: 1.2-3.2), and neuromuscular blockade (OR: 1.9; 95% CI: 1.1-3.3) were associated with increased mortality. Adding postcannulation characteristics to the model, renal complications (OR: 3.0; 95% CI: 1.7-5.2), neurologic complications (OR, 4.7; 95% CI: 1.5-15.2), and pulmonary hemorrhage (OR: 6.4; 95% CI: 1.3-33.2) were associated with increased mortality, whereas Fontan physiology was no longer associated, suggesting the association of Fontan physiology with mortality may be mediated by complications. Fontan physiology was also a risk factor for neurologic complications (OR: 8.2; 95% CI: 3.3-20.9). Given the rapid increase in ECLS use, understanding risk factors for ACHD patients receiving ECLS after cardiac surgery will aid clinicians in decision-making and preoperative planning.

Long-term outcomes after transplantation after support with a pulsatile pediatric ventricular assist device.

BACKGROUND: There has been increasing use of durable ventricular assist devices (VAD) in children as a bridge to transplantation (BTT). The Berlin Heart investigational device exemption (IDE) trial was the first pediatric VAD trial to demonstrate excellent survival outcomes as a BTT. OBJECTIVES: Our aim was to compare the expanded post-transplant outcomes for children enrolled in the Berlin Heart IDE trial to a matched Pediatric Heart Transplant Study (PHTS) cohort not requiring mechanical circulatory support (MCS). SETTING: University Hospitals. METHODS: This was a retrospective review of linked PHTS and Berlin Heart IDE databases for pediatric (≤18 years) recipients transplanted from 2007-2011. Subjects with <5 years of follow up were excluded. VAD supported patients were matched 1:2 to non-VAD supported controls from the PHTS database. RESULTS: Among 109 Berlin Heart IDE study enrollees, 83 were merged with the PHTS database and matched to 166 non-MCS supported patients. There was no difference in diagnosis, status at listing, and age between groups with the expected difference in inotrope use in the non-MCS supported patients. Compared to their matched cohort, there was no statistical difference in 5-year patient survival between VAD and non-VAD patients (81% vs 88%; p = 0.09) nor was there a difference in freedom from rejection or infection. CONCLUSIONS: This data suggests that children supported with a Berlin Heart VAD had similar survival, infection and rejection rates compared to those not requiring MCS support. Continued surveillance of the Berlin Heart IDE trial population post heart transplantation is warranted.

Extracorporeal cardiopulmonary resuscitation.

Extracorporeal life support (ECLS) is used for patients in isolated or combined cardiopulmonary failures. The use of ECLS to rescue patients with cardiac arrest that is refractory to conventional cardiopulmonary resuscitation has been shown to improve survival in many patient populations. Increasing recognition of the survival benefit associated with extracorporeal cardiopulmonary resuscitation (ECPR) has led to increased use of ECPR during the past decade. This review provides an overview of ECPR utilization; population-based clinical outcomes, resource utilization and costs associated this advanced form of life support therapy.

Challenging Argatroban Management of a Child on Extracorporeal Support and Subsequent Heart Transplant.

A 6-year-old child developed heparin-induced thrombocytopenia while on extracorporeal life support. Hours after a difficult transition from heparin to argatroban for anticoagulation therapy, the child underwent heart transplantation. Intraoperative management was plagued with circuit thrombus formation while on cardiopulmonary bypass and subsequent massive hemorrhage after bypass. We review the child's anticoagulation management, clinical challenges encountered, and review current literature related to the use of argatroban in pediatric cardiac surgery.

Pulmonary arteriovenous shunting in the normal fetal lung.

OBJECTIVES: We hypothesized that pulmonary arteriovenous shunting (PAVS) is normally present in fetal lungs and that cavopulmonary anastomosis-induced PAVS may represent a return to an earlier morphologic stage of development. BACKGROUND: The surgical superior cavopulmonary anastomosis is performed as part of the staged Fontan pathway to treat univentricular forms of congenital heart disease; PAVS is a known sequela after superior cavopulmonary anastomosis and may have important clinical consequences. Although the etiology and true morphology of the structures responsible for PAVS are unknown, a leading theory is that PAVS is caused by absence of normal hepatic venous drainage to the pulmonary circulation. METHODS: To determine whether normal fetal lungs demonstrate PAVS, we performed contrast echocardiograms on 13 fetal lambs, 8 neonatal lambs, 4 juvenile lambs, and 4 adult sheep using a blended mixture of saline and blood injected directly into the proximal pulmonary artery. RESULTS: Pulmonary arteriovenous shunting was detected by direct epicardial echocardiography in all fetal lambs (n = 13) and neonatal animals studied at one and three days of life (n = 4) and in two of four animals studied at six to nine days of life. Pulmonary arteriovenous shunting was not present in animals studied at four weeks of life (n = 2) and in adult sheep (n = 5). CONCLUSIONS: These studies demonstrate that PAVS is normally present in late gestation fetal and early neonatal lambs but then disappears during the later neonatal period. Furthermore, these findings suggest that PAVS associated with cavopulmonary anastomosis or other processes affecting the developing pulmonary circulation may represent a return to an earlier morphologic stage of development.

Intrapleural fibrinolysis during pediatric extracorporeal life support.

Pediatric patients who require extracorporeal life support (ECLS) for refractory cardiorespiratory failure are at increased risk for intrapleural hemorrhage due to the effects of systemic anticoagulation and frequent occurrence of pneumothorax. Surgical evacuation is standard therapy for retained hemothorax to prevent secondary empyema, pulmonary compression, and development of fibrothorax. However, surgical interventions during ECLS are hazardous and place patients at increased risk for surgical site bleeding. Intrapleural fibrinolysis with tissue plasminogen activator may be used to facilitate nonsurgical evacuation of retained hemothorax. We present two pediatric patients who were safely and successfully managed with intrapleural fibrinolysis of retained hemothorax during ECLS.

Neoaortic thrombus after Norwood procedure: complication of extracorporeal life support?

Hypoplastic left heart syndrome is the most common diagnosis among infants requiring cardiac extracorporeal life support (ECLS) in the neonatal period, with more than half of patients experiencing an ECLS-related complication. We present a case of nearly obstructing neoaortic thrombus during ECLS occurring in the early postoperative period after modified Norwood palliation of hypoplastic left heart syndrome. Stasis within the neoaortic root due to the increased ventricular afterload associated with venoarterial ECLS may have potentiated this complication. Echocardiographic monitoring and early cardiac catheterization while on ECLS enabled prompt diagnosis and timely surgical correction.

Fatal spontaneous dissection of a Contegra conduit in a child.

The Contegra bovine jugular vein conduit (Medtronic, Minneapolis, MN) is one of the most widely used grafts for surgical reconstruction of the right ventricular outflow tract in both pediatric and adult patients with congenital heart disease. In this report, we describe a case of acute dissection of a neointimal peel in a Contegra conduit resulting in conduit stenosis and death of a child.

Extracorporeal life support for the neonatal cardiac patient: outcomes and new directions.

Extracorporeal life support is an important therapy for neonates with life-threatening cardiopulmonary failure. Utilization of extracorporeal life support in neonates with congenital heart disease has increased dramatically during the past three decades. Despite increased usage, overall survival in these patients has changed very little and extracorporeal life support-related morbidity, including bleeding, neurologic injury, and renal failure, remains a major problem. Although survival is lower and neurologic complications are higher in premature infants than term infants, cardiac extracorporeal life support including extracorporeal cardiopulmonary resuscitation is effective in preventing death in many of these high-risk patients. Miniaturized ventricular assist devices and compact integrated extracorporeal life support systems are being developed to provide additional therapeutic options for neonates.

Modified Blalock-Taussig shunt versus ductal stenting for palliation of cardiac lesions with inadequate pulmonary blood flow.

OBJECTIVE: The modified Blalock-Taussig shunt is the most commonly used palliative procedure for infants with ductal-dependent pulmonary circulation. Recently, catheter-based stenting of the ductus arteriosus has been used by some centers to avoid surgical shunt placement. We evaluated the durability and safety of ductal stenting as an alternative to the modified Blalock-Taussig shunt. METHODS: A single-institution, retrospective review of patients undergoing modified Blalock-Taussig shunt versus ductal stenting was performed. Survival, procedural complications, and freedom from reintervention were the primary outcome variables. RESULTS: A total of 42 shunted and 13 stented patients with similar age and weight were identified. Survival to second-stage palliation, definitive repair, or 12 months was similar between the 2 groups (88% vs 85%; P = .742). The incidence of surgical or catheter-based reintervention to maintain adequate pulmonary blood flow was 26% in the shunted patients and 25% in the stented patients (P = 1.000). Three shunted patients (7%) required intervention to address contralateral pulmonary artery stenosis and 3 (7%) required surgical reintervention to address nonpulmonary blood flow-related complications. The need for ipsilateral or juxtaductal pulmonary artery intervention at, or subsequent to, second-stage palliation or definitive repair was similar between the 2 groups. CONCLUSIONS: Freedom from reintervention to maintain adequate pulmonary blood flow was similar between infants undergoing modified Blalock-Taussig shunt or ductal stenting as an initial palliative procedure. However, a greater percentage of shunted patients experienced procedure-related complications and distal branch pulmonary artery stenosis. Palliative ductal stenting appears to be a safe and effective alternative to modified Blalock-Taussig in selected infants.

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.