Inhaled Carbon Monoxide Provides Cerebral Cytoprotection in Pigs

Carbon monoxide (CO) at low concentrations imparts protective effects in numerous preclinical small animal models of brain injury. Evidence of protection in large animal models of cerebral injury, however, has not been tested. Neurologic deficits following open heart surgery are likely related in part to ischemia reperfusion injury that occurs during cardiopulmonary bypass surgery. Using a model of deep hypothermic circulatory arrest (DHCA) in piglets, we evaluated the effects of CO to reduce cerebral injury. DHCA and cardiopulmonary bypass (CPB) induced significant alterations in metabolic demands, including a decrease in the oxygen/glucose index (OGI), an increase in lactate/glucose index (LGI) and a rise in cerebral blood pressure that ultimately resulted in increased cell death in the neocortex and hippocampus that was completely abrogated in piglets preconditioned with a low, safe dose of CO. Moreover CO-treated animals maintained normal, pre-CPB OGI and LGI and corresponding cerebral sinus pressures with no change in systemic hemodynamics or metabolic intermediates. Collectively, our data demonstrate that inhaled CO may be beneficial in preventing cerebral injury resulting from DHCA and offer important therapeutic options in newborns undergoing DHCA for open heart surgery

Hypothermic cardiopulmonary bypass alters oxygen/glucose uptake in the pediatric brain

AbstractObjectives: Neurologic morbidity related to cardiac surgery has been recognized as a major morbidity. A variety of causes related to cardiopulmonary bypass, including microemboli, nonpulsatile flow, hemodilution, and inflammatory mediation, have been proposed. Because oxygen and glucose are the predominant metabolic substrates for the brain, we sought to examine the uptake of these substrates by the pediatric brain during hypothermic cardiopulmonary bypass. Methods: Eleven children (median age 5 months, range 1 day-17 years) undergoing a variety of cardiac surgical procedures with the use of hypothermic cardiopulmonary bypass were studied. Cerebral arteriovenous differences for oxygen, glucose, and lactate were obtained before, during, and after bypass. On the basis of the predictable stoichiometric relationship for the oxidation of glucose, the relationship of substrate uptake was expressed as the oxygen/glucose index. Oxygen/glucose index (%) = (arteriovenous oxygen difference [μmol/mL]/arteriovenous glucose difference [μmol/mL] × 6) × 100 Results: All children survived with no obvious neurologic sequelae. During cooling on cardiopulmonary bypass, the oxygen/glucose indexes fell significantly from prebypass values (53% ± 19% at 28°C and 54% ± 25% at 24°C vs 117% ± 70%; P <.05, analysis of variance). This decline resulted from decreased oxygen uptake with stable glucose uptake (P <.05). Although oxygen and glucose uptake both increased with rewarming, the net effect was only a slight increase in oxygen/glucose index (62% ± 16%). Postbypass oxygen/glucose index exceeded prebypass values (149% ± 83%). Conclusions: Hypothermic cardiopulmonary bypass alters the relationship between oxygen and glucose uptake in the pediatric brain. The relationship of these findings to bypass-related neurologic morbidity remains to be explored. (J Thorac Cardiovasc Surg 2001;121:366-73

Early repair of hemitruncus: Excellent early and late outcomes

ObjectiveAnomalous origin of 1 of the branch pulmonary arteries from the aorta with 2 normal semilunar valves (hemitruncus) is a rare entity. There have been several small case series reported. We report here our single-institution surgical experience with hemitruncus from 1982 to 2006.MethodsA retrospective case review of all cases of conotruncal anomalies at Children’s Hospital Boston revealed 16 patients with hemitruncus. Ten patients had surgery in the neonatal period (<30 days), 4 at 1 to 6 months, 1 at 8 months, and 1 at 2 years. Diagnosis of hemitruncus was the indication for operation in all but 1. Fourteen of the 16 had anomalous right pulmonary artery from aorta, and 2 had left pulmonary artery from aorta. Common associated anomalies included patent foramen ovale in 14, patent ductus arteriosus in 11, and ventricular septal defect in 4. All patients had elevated right ventricular pressures with systemic pressures in 5 and suprasystemic pressures in 9.ResultsThere was 1 operative death in this series in an infant who died from sepsis following ligation of a tracheoesophageal fistula. One patient required reoperation for supravalvar aortic stenosis and right pulmonary artery stenosis 1 year postoperatively. Three patients required 4 catheter-based interventions postoperatively. At 20 years, survival by Kaplan–Meier was 93%; freedom from reoperation, 93%; and freedom from catheter reintervention, 79%.ConclusionsEarly repair of hemitruncus results in excellent hemodynamic and anatomic results. Survival is excellent, with a low incidence of reoperation or reintervention

Surgical repair of truncal valve regurgitation†

OBJECTIVES Truncal valve regurgitation remains a short- and long-term risk factor for patients with truncus arteriosus. There are limited data available on techniques and outcomes of truncal valve repair (TVR). The aim of this study was to report our experience with TVR in patients of all ages. METHODS From 1997 to 2012, 36 patients (13 neonates, 30 children and 3 adults) underwent TVR for significant regurgitation. RESULTS There were 3 early deaths (8%), all of which were in neonates. Twenty-two patients had a quadricuspid, 13 a tricuspid and 1 a bicuspid truncal valve before repair. Valve repair improved regurgitation in 31 of 36 repairs. The median regurgitation decreased from moderate-severe to mild (P < 0.001). During a mean follow-up of 38.3 ± 44.9 months (range 1 month—15 years), there was 1 late death, 16 patients required reoperation on the truncal valve and 1 required a second reoperation. Freedom from reoperation was 91.4 ± 4.8% at 1 year, 55.0 ± 10.4% at 5 and 22.9 ± 12.2% at 10 years. A quadricuspid valve after repair tended to worsen freedom from reoperation (P = 0.15), and tricuspidization tended to improve freedom from reoperation (P = 0.19). Neonatal repair (hazards ratio (HR) 4.1, P = 0.03) and leaflet thinning (HR 22.5, P = 0.002) were independent predictors of reoperation. CONCLUSIONS Valve repair for truncal valve regurgitation is feasible, with good results. Surgical creation of a tricuspid truncal valve seems to provide the best outcomes in this challenging populatio

Mitral valve replacement in infants and children 5 years of age or younger: Evolution in practice and outcome over three decades with a focus on supra-annular prosthesis implantation

ObjectiveSuccessful mitral valve replacement in young children is limited by the lack of small prosthetic valves. Supra-annular prosthesis implantation can facilitate mitral valve replacement with a larger prosthesis in children with a small annulus, but little is known about its effect on the outcomes of mitral valve replacement in young children.MethodsOne hundred eighteen children underwent mitral valve replacement at 5 years of age or younger from 1976–2006. Mitral valve replacement was supra-annular in 37 (32%) patients.ResultsSurvival was 74% ± 4% at 1 year and 56% ± 5% at 10 years but improved over time (10-year survival of 83% ± 7% from 1994–2006). Factors associated with worse survival included earlier mitral valve replacement date, age less than 1 year, complete atrioventricular canal, and additional procedures at mitral valve replacement, but not supra-annular mitral valve replacement. As survival improved during our more recent experience, the risks of supra-annular mitral valve replacement became apparent; survival was worse among patients with a supra-annular prosthesis after 1991. A pacemaker was placed in 18 (15%) patients within 1 month of mitral valve replacement and was less likely in patients who had undergone supra-annular mitral valve replacement. Among early survivors, freedom from redo mitral valve replacement was 72% ± 5% at 5 years and 45% ± 7% at 10 years. Twenty-one patients with a supra-annular prosthesis underwent redo mitral valve replacement. The second prosthesis was annular in 15 of these patients and upsized in all but 1, but 5 required pacemaker placement for heart block.ConclusionsSupra-annular mitral valve replacement was associated with worse survival than annular mitral valve replacement in our recent experience. Patients with supra-annular mitral valve replacement were less likely to have operative complete heart block but remained at risk when the prosthesis was subsequently replaced

Primary left ventricular rehabilitation is effective in maintaining two-ventricle physiology in the borderline left heart

ObjectiveBorderline left heart disease is characterized by left heart obstructive lesions (coarctation, aortic and mitral stenoses, left ventricular hypoplasia) and endocardial fibroelastosis. The multilevel obstruction and impaired left ventricular systolic and diastolic function contribute to failure of biventricular circulation. We studied the effects of left ventricular rehabilitation—endocardial fibroelastosis resection with mitral or aortic valvuloplasty—on left ventricular function and clinical outcomes.MethodsAll patients with borderline left heart structures and endocardial fibroelastosis who underwent a primary left ventricular rehabilitation procedure were retrospectively analyzed to determine operative mortality, reintervention rates, and hemodynamic status. Left heart dimensions and hemodynamics were recorded from preoperative and postoperative echocardiogram and cardiac catheterization. Postoperative left atrial pressure was obtained from the intracardiac line early after left ventricular rehabilitation. Preoperative and postoperative values were compared by paired t test.ResultsBetween 1999 and 2008, 9 patients with endocardial fibroelastosis and borderline left heart disease underwent left ventricular rehabilitation at a median age of 5.6 months (range, 1–38 months). There was no operative mortality, and at a median follow-up of 25 months (6 months to 10 years) there was 1 death from noncardiac causes and 2 patients required reoperations. Significant increases in ejection fraction and left ventricular end-diastolic volume were observed, whereas left atrial pressure and right ventricular/left ventricular pressure ratios decreased postoperatively.ConclusionIn patients with borderline left hearts, primary left ventricular rehabilitation with endocardial fibroelastosis resection and mitral and aortic valvuloplasty results in improved left ventricular systolic and diastolic performance and decreased right ventricular pressures. This approach may provide an alternative to single-ventricle management in this difficult patient group

Association between Technical Performance Scores and neurodevelopmental outcomes after congenital cardiac surgery

ObjectivesTechnical Performance Score (TPS) has been shown to have a strong association with early and late outcomes after congenital cardiac surgery, with greater morbidity and reintervention in children with major residual lesions (TPS class 3). We sought to explore the effect of TPS on the neurodevelopmental outcomes.MethodsAll infants undergoing cardiac surgery, excluding those with trisomy 21, were offered neurodevelopmental testing at 1 year of age using the Bayley Scales of Infant Development, 3rd edition. TPSs from the discharge echocardiograms were graded as class 1 (optimal), class 2 (minor residual), or class 3 (major residual). Multivariate regression analysis was performed using patient characteristics and preoperative variables.ResultsNeurodevelopmental testing was performed in 140 patients at a median age of 16 months. Of these, 28 (20%) had single ventricle palliation; 39 (28%) were in Risk Adjustment for Congenital Heart Surgery category 4 to 6. Significant differences between the groups were found in the cognitive (P = .01) and motor (P = .05) domains, with subjects in TPS class 3 having significantly lower cognitive and motor composite scores. The scores did not vary significantly according to single ventricle versus biventricular repair or Risk Adjustment for Congenital Heart Surgery categorization. In multivariate modeling, class 3 TPS remained significantly associated with a lower Bayley cognitive score (P = .02), with a trend toward a lower Bayley motor score (P = .08).ConclusionsWe found that TPS is an independent predictor of neurodevelopmental outcomes after infant heart surgery. Future research should explore whether a structured program of intraoperative recognition and intervention on residual lesions can improve the TPS and neurodevelopmental outcomes

Staged Left Ventricular Recruitment After Single-Ventricle Palliation in Patients With Borderline Left Heart Hypoplasia

ObjectivesThe goal of this study was to review results of a novel management strategy intended to rehabilitate the left heart (LH) in patients with LH hypoplasia who have undergone single-ventricle palliation (SVP).BackgroundManagement of patients with hypoplastic LH syndrome and borderline left ventricle (LV) involves 2 options: SVP or biventricular repair. We hypothesized that staged LV recruitment and biventricular conversion may be achieved after SVP by using a strategy consisting of relief of inflow and outflow tract obstructions, resection of endocardial fibroelastosis, and promotion of flow through the LV.MethodsPatients with hypoplastic LH and borderline LV who underwent traditional SVP (n = 34) or staged LV recruitment (n = 34) between 1995 and 2010 were retrospectively analyzed and compared with a control SVP group.ResultsMean initial z-scores for LH structures before stage 1 SVP were not significantly different between groups. Mortality occurred in 4 of 34 patients after LV recruitment and in 7 of 34 after traditional SVP. LH dimension z-scores increased significantly over time after LV recruitment, whereas they declined after traditional SVP, with significant interaction between stage of palliation and treatment group. Restriction of the atrial septum (conducted in 19 of 34 patients) was the only predictor of increase in left ventricular end-diastolic volume (p < 0.001). Native biventricular circulation was achieved in 12 patients after staged LV recruitment; all of these patients had restriction at the atrial septum.ConclusionsIn these patients with borderline LH disease who underwent SVP, it is possible to increase LH dimensions by using an LV recruitment strategy. In a subset of patients, this strategy allowed establishment of biventricular circulation

The Safety and Efficacy of Antifibrinolytic Therapy in Neonatal Cardiac Surgery

Background: Neonates undergoing open-heart surgery are particularly at risk of postoperative bleeding requiring blood transfusion. Aprotinin has attained high efficacy in reducing the requirement for a blood transfusion following a cardiopulmonary bypass, but is seldom studied in the neonatal age group. The aim of this study was to compare the efficacy and adverse effects of aprotinin and tranexamic acid in neonates undergoing open-heart surgery at a single centre. Methods: Between October 2003 and March 2008, perioperative data of 552 consecutive neonatal patients undergoing open-heart surgery in Children’s Hospital Boston were reviewed. Among them, 177 did not receive antifibrinolytic therapy (Group A); 100 were treated with tranexamic acid only (Group B); and 275 patients received aprotinin with or without tranexamic acid (Group C). Except for antifibrinolytic therapy, the anaesthesiological and surgical protocols remained identical. Postoperative complications and in-hospital mortality were the primary study endpoints. Results: Body weight and Risk Adjustment for Congenital Heart Surgery (RACHS-1) scores were statistically comparable among the three groups. No statistically significant differences were observed between the duration of hospitalization, chest tube drainage, reexploration for bleeding, and kidney function impairment. In Group C, less blood was transfused within 24 hours than in GroupB. Operative mortality was similar among the three groups. Conclusion: No further risk and kidney injury were observed in the use of aprotinin in neonatal cardiac surgery, aprotinin demonstrated a reduced requirement for blood transfusion compared with tranexamic acid. Our data provide reasonable evidence that aprotinin and tranexamic acid are safe and efficacious as antifibrinolytic modalities in neonatal patients undergoing cardiac surgery