Christopher D. Derby

Improving the outcome of high-risk neonates with hypoplastic left heart syndrome: hybrid procedure or conventional surgical palliation? §

OBJECTIVES Despite significant progress, surgical outcome for high-risk patients with hypoplastic left heart syndrome (HLHS) remain suboptimal. The hybrid palliation lessens the initial operative insult and is expected to improve overall survival; however the outcome of this management sequence is unknown. METHODS Retrospective review of all high-risk neonates (prematurity, low birth weight, associated genetic or co-morbid conditions) undergoing initial palliation for HLHS either by hybrid or Stage I Norwood procedure at a single institution between January 2001 and December 2006. The two strategies were compared using survival after stage II as the end-point for outcome. RESULTS The cohort included 33 patients (14 hybrid and 19 Norwood) with a mean age of 3.8+/-2.4 days, weight of 2.6+/-0.6 kg and Aristotle comprehensive score of 18.7+/-2.5. Aortic atresia was present in 5/14 hybrid and 12/19 Norwood patients. The mean gestational age was 36.8+/-2.2 weeks, six patients were under 36 weeks in each group. Patients undergoing hybrid palliation had a lower preoperative pH [7.14+/-0.2 vs 7.25+/-0.05, p=0.04], higher incidence of organ dysfunction [9/14 (64%) vs 5/19 (26%), p=0.03] and less associated cardiac anomalies [3/13 (21%) vs 13/19 (68%), p=0.009]. Hospital mortality and interstage mortality was 7/33 (21%) and 6/26 (23%) for the entire cohort, without significant differences between the hybrid and the conventional Norwood strategies. Of the original 33 patients only 16 (48.5%) were alive following the second stage procedure (7/14 (50%) hybrid and 9/19 (47.4%) Norwood). CONCLUSIONS Regardless of the type of initial palliation, high-risk neonates with HLHS continue to have decreased survival. Although the hybrid approach reduces the initial surgical insult, important interstage mortality and ongoing morbidity result in survival no different than with conventional surgical palliation.

In situ crosslinkable heparin-containing poly(ethylene glycol) hydrogels for sustained anticoagulant release.

Low-molecular weight heparin (LMWH) is widely used in anticoagulation therapies and for the prevention of thrombosis. LMWH is administered by subcutaneous injection usually once or twice per day. This frequent and invasive delivery modality leads to compliance issues for individuals on prolonged therapeutic courses, particularly pediatric patients. Here, we report a long-term delivery method for LMWH via subcutaneous injection of long-lasting hydrogels. LMWH is modified with reactive maleimide groups so that it can be crosslinked into continuous networks with four-arm thiolated poly(ethylene glycol) (PEG-SH). Maleimide-modified LMWH (Mal-LMWH) retains bioactivity as indicated by prolonged coagulation time. Hydrogels comprising PEG-SH and Mal-LMWH degrade via hydrolysis, releasing bioactive LMWH by first-order kinetics with little initial burst release. Separately dissolved Mal-LMWH and PEG-SH solutions were co-injected subcutaneously in New Zealand White rabbits. The injected solutions successfully formed hydrogels in situ and released LMWH as measured via chromogenic assays on plasma samples, with accumulation of LMWH occurring at day 2 and rising to near-therapeutic dose equivalency by day 5. These results demonstrate the feasibility of using LMWH-containing, crosslinked hydrogels for sustained and controlled release of anticoagulants.

An unusual case of button battery-induced traumatic tracheoesophageal fistula.

Background: Much of pediatric medicine is focused on prevention of disease and injury. Although accidental ingestions of various household chemicals and medicines are well described and the treatment is supported by local poison control hotlines, the ingestion of button batteries by children is less publicized, and the dangers are less understood by both parents and health care providers. Methods: We describe a case report of a 17-month-old girl with no significant medical history who presented with respiratory distress, cough, and fever and subsequently was discovered to have ingested a button battery. Results: The formation of a traumatic tracheoesophageal fistula required intensive management that escalated to cardiopulmonary bypass and eventual pericardial patch closure of the tracheal defect after the failure of conventional mechanical ventilation. Conclusions: Esophageal button battery impaction places the patient at high risk for full-thickness damage to the esophagus and tracheal structures with fistula formation in as little as a few hours. The key to successful therapy is prompt diagnosis and removal, but in nonverbal pediatric patients, this often is not achievable. Because of the complications associated with this disease (tracheoesophageal fistula) and subsequent difficulties associated with oxygenation and ventilation, these patients should be managed at an institution with the skilled capability of providing cardiopulmonary bypass quickly as a potentially lifesaving therapy.

Predictive value of near-infrared spectroscopy on neurodevelopmental outcome after surgery for congenital heart disease in infancy

OBJECTIVE To explore the relationship between intraoperative regional cerebral oxygen saturation (rSO(2)) measured by near-infrared spectroscopy (NIRS) and neurodevelopmental outcome in children after cardiac surgery. METHODS Cross-sectional neurodevelopmental evaluation at 2 years of age was performed in a cohort of young infants who had surgery for congenital heart disease in 2007. The third edition of Bayley Scales of Infant and Toddler Development (Bayley-III) was used to assess cognitive, language, and motor functioning. Clinical and perioperative data were collected, including intraoperative rSO(2) nadir, rSO(2) percent decrease from baseline, and cumulative minutes of at least 20%, 30%, and 40% decrease from baseline. RESULTS Twenty-seven patients without chromosomal abnormality were included in analyses. Mean Bayley-III scores fell within 1 standard deviation of the normative mean. Stepwise regression analyses of patient- and procedure-related variables, including rSO(2), demonstrated that cognitive ability was predicted by length of hospital stay and premature birth (58.1% of variance), receptive communication was predicted by length of hospital stay and rSO(2) nadir (40.2% of variance), expressive communication was predicted by birth weight (26.2% of variance), fine motor functioning was predicted by duration of cardiac intensive care unit stay (41.4% of variance), and gross motor functioning was predicted by the presence of a significant comorbidity (43.5% of variance). CONCLUSIONS In a contemporary cohort of infants undergoing surgery for congenital heart disease, neurodevelopmental outcomes at 2 years of age are largely influenced by patient-related characteristics. Although receptive communication appears to be influenced by rSO(2) nadir, the predictive value of NIRS remains unclear.

Routine primary repair of tetralogy of Fallot in the neonate

Uncertainty surrounds both the timing and ideal form of early management of tetralogy of Fallot. Some centers perform early complete repair in all patients regardless of age, symptoms and morphology. Others recommend a two-stage approach involving initial palliation in symptomatic neonates and young infants and those with unfavorable anatomy (anomalous coronary anatomy or hypoplastic pulmonary arteries). Advantages of early anatomic correction include alleviation of cyanosis, normal growth and organ development, removal of stimulus for right ventricular hypertrophy and avoidance of risks associated with initial palliation. With recent advances in anesthetic, operative and postoperative management, routine primary repair of tetralogy of Fallot in the neonate and young infant can be accomplished with excellent early and mid-term results. However, long-term follow-up is necessary to assess the impact of early repair on late right ventricular function, arrhythmias and need for reintervention.

Stage II Reconstruction After Hybrid Palliation for High-Risk Patients With a Single Ventricle

BACKGROUND The hybrid approach to palliate high-risk neonates with a single ventricle and systemic outflow obstruction continues to gain interest. Despite early success, few data exist regarding the physiologic adequacy of this palliation and the outcome of the stage II reconstruction. METHODS We reviewed our experience with stage II reconstruction after hybrid palliation in high-risk newborns with hypoplastic left heart syndrome and variants, focusing on the hemodynamic, reintervention, and operative data. RESULTS Among 14 patients undergoing hybrid palliation, interstage reinterventions targeted the ductal stent in 2, the atrial septal communication in 3, and the pulmonary artery bands in 1 patient. The median ratio of pulmonary blood flow to systemic blood flow (Qp/Qs) was 0.76, and pulmonary artery pressure was 14 mm Hg. Stage II reconstruction was performed in 8 patients with a median age of 4 months (range, 3.2 to 5.8 months) and a median weight of 4.9 kg (range, 3.7 to 6.0 kg). Median cardiopulmonary bypass time was 124 minutes (range, 95 to 188 minutes). Median time to extubation was 20 hours (range, 9 to 120 hours). Median oxygen saturation at hospital discharge was 79% (range, 78% to 82%). Two perioperative deaths occurred. To date, all hospital survivors are well. Four patients have completed a Fontan. CONCLUSIONS Stage II reconstruction after hybrid palliation for high-risk neonates carries important morbidity and mortality. A considerable number of reinterventions to optimize the palliated physiology are necessary. This approach can provide appropriate preparation for single-ventricle management while avoiding cardiopulmonary bypass in the neonate. Additional experience and critical risk assessment of the entire strategy are necessary to define its advantages.

Aristotle score predicts outcome in patients requiring extracorporeal circulatory support following repair of congenital heart disease.

Extracorporeal membrane oxygenation (ECMO) has become the standard technique of mechanical support for the failing circulation following repair of congenital heart lesions. The objective of this study was to identify predictors of survival in patients requiring postcardiotomy ECMO. The Aristotle score, a method developed to evaluate quality of care based on complexity, was investigated as a potential predictor of outcome. Between 2003 and 2005, 37 patients required ECMO following corrective surgery for congenital heart disease. Records were reviewed retrospectively with emphasis on factors affecting survival to discharge. The comprehensive Aristotle complexity score was calculated for each patient. Overall, 28 patients (76%) survived to decannulation and 17 patients (46%) survived to discharge. There were 24 (65%) neonates and 10 patients (27%) with single ventricle physiology, with a hospital survival of 42% (10 of 24) and 50% (5 of 10), respectively. Univariate factors associated with survival included Aristotle score, duration of support, reexploration, multiple organ failure, and number of complications. Age, weight, and single-ventricle physiology were not significant. In a logistic regression model, an Aristotle score < 14 was identified as a predictor of survival (OR 0.12, CI 0.02–0.87). The Aristotle score is predictive of outcome in patients requiring postcardiotomy ECMO and may serve as a uniform criterion when comparing and evaluating quality of care and performance in this complex patient population.

Valve-sparing neo-aortic root replacement after Fontan completion for hypoplastic left heart syndrome

Development of neo-aortic root dilatation is a well-known entity among patients with congenital heart defects in whom the native pulmonary root is placed in the systemic position. Patients undergoing a Norwood procedure constitute no exception. Valve-sparing aortic root replacement, a procedure commonly utilized to treat aortic root dilatation among patients with connective tissue disorders, can be an effective form of therapy for this condition.

Outcomes following non-valved autologous reconstruction of the right ventricular outflow tract in neonates and infants.

OBJECTIVE Controversy surrounds the optimal method of establishing right ventricle to pulmonary artery continuity in neonates and infants with congenital heart disease. We reviewed our experience with non-valved autologous reconstruction of the right ventricular outflow tract to determine mid-term outcome and risk factors for reintervention. METHODS Between 1998 and 2006, 34 consecutive patients underwent non-valved autologous right ventricular outflow tract reconstruction. The need for postoperative catheter-based intervention or reoperation was assessed using relevant patient and procedure-related variables. RESULTS Diagnoses included tetralogy of Fallot with anomalous coronary (n=3), tetralogy of Fallot with pulmonary atresia (n=10), truncus arteriosus communis (n=15), and other (n=6). Median age at surgery was 5 days (1-270 days). Twenty-six (76%) patients were neonates. Median weight was 3.1kg (1.8-7.3kg). At a median follow-up of 43 months (1-90 months), 15 (50%) patients underwent reoperation and 7 (23%) underwent catheter-based intervention, with a total of 16 (53%) undergoing either reoperation or catheter-based intervention. Kaplan-Meier freedom from reintervention at 6 months, 1 year, 3 years, and 5 years was 67%, 47%, 47%, and 35% for truncus arteriosus versus 87%, 82%, 68%, and 65% for diagnoses other than truncus arteriosus (p=0.05). CONCLUSIONS Mid-term outcome following non-valved autologous reconstruction of the right ventricular outflow tract is satisfactory and constitutes a sound alternative to the use of small-diameter conduits in neonates and infants. In our hands, this strategy favors certain anatomic subtypes. Non-truncus patients have significantly lower rates of reintervention. Technical details associated with the anatomical reconstruction of the posterior autologous pathway may play an important role in outcomes.

Hard choices for high-risk patients with critical left ventricular outflow obstruction: contemporary comparison of hybrid versus surgical strategy.

Surgical management of high-risk newborns with critical left ventricular outflow tract obstruction (LVOTO) involves difficult decision making and complex procedures associated with significant morbidity and mortality. We sought to compare the outcomes of the hybrid and surgical strategies for the management of neonates with critical LVOTO considered at high risk in a contemporary nonrandomized cohort. This is a retrospective review of all patients undergoing management of critical LVOTO between January 2001 and December 2008. High-risk conditions included prematurity, low birth weight, and genetic or associated cardiac and noncardiac pathology. Analysis was performed based on intention to treat. Primary and secondary outcomes were operative and 6-month mortality. The cohort included 55 patients (21 hybrid and 34 surgical [31 Norwood, 3 biventricular repair]). The cohort had a median age of 4 (range, 1-62) days, mean weight of 2.7 ± 0.5 kg, and Aristotle comprehensive score of 18.6 ± 2.9. Low birth weight (P = .0007), prematurity (P = .004), and organ dysfunction (P = .04) were risk factors for operative death. Six-month mortality was associated with need for reintervention (P = .017) in the surgical group and history of organ dysfunction (P = .02) or aortic atresia (P = .03) in the hybrid group. Logistic regression identified low birth weight (P = .05; odds ratio [OR], 5.6 [0.9-34.6]), organ dysfunction (P = .05; OR, 4.7 [0.9-22.5]), and non–hypoplastic left heart syndrome (HLHS) diagnosis (P = .03; OR, 0.06 [0.005-0.93]) as predictors of mortality for the entire cohort. No differences in operative and 6-month mortality were detected between management strategies. Although initial surgical insult is lessened by the hybrid palliation, important interstage mortality and ongoing morbidity result in similar 6-month survival with either strategy. Patient-related factors have a larger influence on outcome than the management strategy chosen.