Porcine Model of the Arterial Switch Operation: Implications for Unique Strategies in the Management of Hypoplastic Left Ventricles.

There are no reports on the performance of the arterial switch operation (ASO) in a normal heart with normally related great vessels. The objective of this study was to determine whether the ASO could be performed in a healthy animal model. Cardiopulmonary bypass (CPB) and coronary translocation techniques were used to perform ASO in neonatal piglets or a staged ASO with prior main pulmonary artery (PA) banding. Primary ASO was performed in four neonatal piglets. Coronary translocation was effective with angiograms confirming patency. Piglets could not be weaned from CPB due to right ventricle (RV) dysfunction. To improve RV function for the ASO, nine piglets had PA banding. All survived the procedure. Post-banding RV pressure increased from a mean of 20.3 ± 2.2 mmHg to 36.5 ± 7.3 mmHg (p = 0.007). At 58 ± 1 days post-banding, piglets underwent cardiac MRIs revealing RV hypertrophy, and RV pressure overload with mildly reduced RV function. Catheterization confirmed RV systolic pressures of 84.0 ± 6.7 mmHg with LV systolic pressure 83.3 ± 6.7 mmHg (p = 0.43). The remaining five PA banded piglets underwent ASO at 51 ± 0 days post-banding. Three of five were weaned from bypass with patent coronary arteries and adequate RV function. We were able to successfully perform an arterial switch with documented patent coronary arteries on standard anatomy great vessels in a healthy animal model. To our knowledge this is the first time this procedure has been successfully performed. The model may have implications for studying the failing systemic RV, and may support a novel approach for management of borderline, pulsatile left ventricles.

Feasibility Study of Catheter-Based Interventions for Anisotropic Expanded Polytetrafluoroethylene Cardiovascular Conduits in a Growing Lamb Model.

BACKGROUND: Cardiovascular repair in children often requires implant of conduits which do not have growth potential and will require reoperation. In the current study we sought to determine the feasibility of catheter-based interventions of anisotropic conduits inserted as interposition grafts in the main pulmonary artery (MPA) of growing lambs. METHODS: Lambs underwent interpositional implant of either an anisotropic expanded polytetrafluoroethylene (ePTFE) (Test) conduit or conventional PTFE (Control) conduit. In the postoperative period, lambs were anesthetized and underwent catheter-based interventions consisting of hemodynamic and angiographic data collection, balloon dilation and/or stenting of the conduit at 3, 6 or 9 month postoperative time point. RESULTS: At 3 months, control lambs showed significant increases in right ventricular pressures and trans-conduit gradients in comparison to test lambs. Test conduit diameters were significantly larger compared to controls due to spontaneous radial expansion of the anisotropic conduit. Balloon dilation of test conduits at 3 and 6 months showed a reduction in RV pressure and statistically significant improvement in the RV outflow tract gradient as well as significant increase in graft diameter, compared to both control and pre-dilation conditions. Furthermore, the test conduit diameter increased significantly compared to the pre-balloon and control conditions at each time point. Necropsy of test conduits showed no evidence of tears, perforations, or clot and smooth interiors with well-healed anastomoses. CONCLUSIONS: Anisotropic conduits implanted as interposition grafts in the MPA show spontaneous expansion, and can safely and effectively undergo catheter-based interventions, with significant increases in graft diameter occurring after balloon dilation.

Anisotropic Polytetrafluoroethylene Cardiovascular Conduits Spontaneously Expand in a Growing Lamb Model.

BACKGROUND: Insertion of conduits from the right ventricle (RV) to the pulmonary artery (PA) is a commonly used technique for repair of congenital heart defects. The vast majority of infants and children will require reoperation and/or re-intervention to replace the conduit. Some children may require multiple reoperations, with the risk of death and morbidity increasing significantly with each subsequent operation. We evaluated the feasibility and performance of a relatively novel anisotropic conduit for cardiovascular repair in the growing lamb model. MATERIALS AND METHODS: Lambs were allocated into a control (n = 3) or test (n = 4, anisotropic) conduit group. Control conventional polytetrafluoroethylene (PTFE) conduits or test anisotropic expanded PTFE (ePTFE) based test conduits measuring 10-11 mm in diameter were sewn as interpositional grafts in the main pulmonary artery (MPA) and followed up to 6 months. Clinical and echocardiographic evaluations were performed monthly with hemodynamic and angiographic assessment at 3 and 6 months. RESULTS: Control conduits did not expand, all 3 animals developed one or more adverse events including tachypnea, ascites, inappetence, lethargy, and mortality due to severe right heart failure and significantly higher peak trans-conduit gradients (48.5 ± 5.1 p = 0.02). The test conduits spontaneously expanded up to 14.8 ± 0.8 mm in diameter, no adverse events were observed in any animals and trans-conduit gradients were significantly lower (27.0 ± 8.3, p = 0.02). CONCLUSIONS: Anisotropic ePTFE conduits can be safely implanted in growing lambs with stable hemodynamics. This spontaneously expanding anisotropic conduit may represent a novel approach to congenital heart repairs that would avoid the need for reoperation or multiple operations.

Use of virtual reality for pre-surgical planning in separation of conjoined twins: A case report.

We describe the use of virtual reality technology for surgical planning in the successful separation of thoracopagus conjoined twins. Three-dimensional models were created from computed tomography angiograms to simulate the patient's anatomy on a virtual stereoscopic display. Members of the surgical teams reviewed the anatomical models to localize an interatrial communication that allowed blood to flow between the two hearts. The surgical plan to close the 1-mm interatrial communication was significantly modified based on the pre-procedural spatial awareness of the anatomy presented in the virtual visualization. The virtual stereoscopic display was critical for the surgical team to successfully separate the twins and provides a useful case study for the use of virtual reality technology in surgical planning. Both twins survived the operation and were subsequently discharged from the hospital.

Mechanical hemolysis in pediatric patients associated with rapid transfusion and one-way valve.

BACKGROUND: Four similar transfusion reactions involving infants were reported in less than 1 year. After transfusion of red blood cells (RBCs) via syringe in the operating room, each patient experienced discolored urine, laboratory evidence of hemolysis, and acute kidney injury. Clerical and serologic investigations were unremarkable. Mechanical hemolysis was considered. STUDY DESIGN AND METHODS: Simulated syringe transfusions were performed. Measurements included hematocrit (Hct), free hemoglobin, and visual hemolysis index. Washed and unwashed RBCs were tested with or without a recently introduced one-way valve, using a 24- or 16-gauge intravenous catheter. Constant manual pressure (1.43 ± 0.49 mL/sec) or syringe pump (2 mL/min) was used and a subset was timed. RESULTS: The valve increased hemolysis during manual transfusion using both catheters with washed and unwashed RBCs. With the 24-gauge catheter, the change in Hct was -3.53 ± 0.69% with the valve and 0.22 ± 0.13% without (p < 0.00001). Comparing the individual valves tested, differences in hemolysis were observed (change in Hct, p < 0.0001). During manual transfusion with 24-gauge catheter and unwashed RBCs, the degree of hemolysis was greater when it took longer to transfuse with a valve (change in Hct versus time, r = -0.75, p < 0.0001) compared to a slight increase in hemolysis for samples that took less time to transfuse without a valve (change in Hct versus time, r = 0.58, p = 0.23). CONCLUSIONS: Mechanical hemolysis should be considered when investigating possible hemolytic transfusion reactions, especially with high rates of transfusion and use of a valve. During rapid manual transfusion with the valve, greater resistance was associated with increased hemolysis.

Minimizing the risk of preoperative brain injury in neonates with aortic arch obstruction.

OBJECTIVE: To determine whether prenatal diagnosis lowers the risk of preoperative brain injury by assessing differences in the incidence of preoperative brain injury across centers. STUDY DESIGN: From 2 prospective cohorts of newborns with complex congenital heart disease studied by preoperative cerebral magnetic resonance imaging, one cohort from the University Medical Center Utrecht (UMCU) and a combined cohort from the University of California San Francisco (UCSF) and University of British Columbia (UBC), patients with aortic arch obstruction were selected and their imaging and clinical course reviewed. RESULTS: Birth characteristics were comparable between UMCU (n = 33) and UCSF/UBC (n = 54). Patients had a hypoplastic aortic arch with either coarctation/interruption or hypoplastic left heart syndrome. In subjects with prenatal diagnosis, there was a significant difference in the prevalence of white matter injury (WMI) between centers (11 of 22 [50%] at UMCU vs 4 of 30 [13%] at UCSF/UBC; P < .01). Prenatal diagnosis was protective for WMI at UCSF/UBC (13% prenatal diagnoses vs 50% postnatal diagnoses; P < .01), but not at UMCU (50% vs 46%, respectively; P > .99). Differences in clinical practice between prenatally diagnosed subjects at UMCU vs UCSF/UBC included older age at surgery, less time spent in the intensive care unit, greater use of diuretics, less use of total parenteral nutrition (P < .01), and a greater incidence of infections (P = .01). In patients diagnosed postnatally, the prevalence of WMI was similar in the 2 centers (46% at UMCU vs 50% at UCSF/UBC; P > .99). Stroke prevalence was similar in the 2 centers regardless of prenatal diagnosis (prenatal diagnosis: 4.5% at Utrecht vs 6.7% at UCSF/UBC, P = .75; postnatal diagnosis: 9.1% vs 13%, respectively, P > .99). CONCLUSION: Prenatal diagnosis can be protective for WMI, but this protection may be dependent on specific clinical management practices that differ across centers.

Preoperative B-type natriuretic peptide levels are associated with outcome after total cavopulmonary connection (Fontan).

OBJECTIVE: The study objective was to determine the association between preoperative B-type natriuretic peptide levels and outcome after total cavopulmonary connection. Surgical palliation of univentricular cardiac defects requires a series of staged operations, ending in a total cavopulmonary connection. Although outcomes have improved, there remains an unpredictable risk of early total cavopulmonary connection takedown. The prediction of adverse postoperative outcomes is imprecise, despite an extensive preoperative evaluation. METHODS: We prospectively enrolled 50 patients undergoing total cavopulmonary connection. We collected preoperative clinical data, preoperative plasma B-type natriuretic peptide levels, and postoperative outcomes, including the incidence of an adverse outcome within 1 year of surgery (defined as death, total cavopulmonary connection takedown, or the need for cardiac transplantation). RESULTS: The mean age of patients was 4.7 years (standard deviation, 2.1 years). The median (interquartile range) preoperative B-type natriuretic peptide levels were higher in patients who required total cavopulmonary connection takedown and early postoperative mechanical cardiac support (n = 3; median, 55; interquartile range, 42-121) compared with those with a good outcome (n = 47; median, 11; interquartile range, 5-17) (P < .05). A preoperative B-type natriuretic peptide level of 40 pg/mL or greater was highly associated with the need for total cavopulmonary connection takedown (sensitivity, 100%; specificity, 93%; P < .05), yielding a positive predictive value of 50% and a negative predictive value of 100%. Higher preoperative B-type natriuretic peptide levels also were associated with longer intensive care unit length of stay, longer hospital length of stay, and increased incidence of low cardiac output syndrome (P < .05). CONCLUSIONS: Preoperative B-type natriuretic peptide blood levels are uniquely associated with the need for mechanical support early after total cavopulmonary connection and total cavopulmonary connection takedown, and thus may provide important information in addition to the standard preoperative assessment.

The effect of preoperative nutritional status on postoperative outcomes in children undergoing surgery for congenital heart defects in San Francisco (UCSF) and Guatemala City (UNICAR).

OBJECTIVE: The objective of this study was to determine the association between preoperative nutritional status and postoperative outcomes in children undergoing surgery for congenital heart defects (CHD). METHODS: Seventy-one patients with CHD were enrolled in a prospective, 2-center cohort study. We adjusted for baseline risk differences using a standardized risk adjustment score for surgery for CHD. We assigned a World Health Organization z score for each subject's preoperative triceps skin-fold measurement, an assessment of total body fat mass. We obtained preoperative plasma concentrations of markers of nutritional status (prealbumin, albumin) and myocardial stress (B-type natriuretic peptide [BNP]). Associations between indices of preoperative nutritional status and clinical outcomes were sought. RESULTS: Subjects had a median (interquartile range [IQR]) age of 10.2 (33) months. In the University of California at San Francisco (UCSF) cohort, duration of mechanical ventilation (median, 19 hours; IQR, 29 hours), length of intensive care unit stay (median, 5 days; IQR 5 days), duration of any continuous inotropic infusion (median, 66 hours; IQR 72 hours), and preoperative BNP levels (median, 30 pg/mL; IQR, 75 pg/mL) were associated with a lower preoperative triceps skin-fold z score (P < .05). Longer duration of any continuous inotropic infusion and higher preoperative BNP levels were also associated with lower preoperative prealbumin (12.1 ± 0.5 mg/dL) and albumin (3.2 ± 0.1; P < .05) levels. CONCLUSIONS: Lower total body fat mass and acute and chronic malnourishment are associated with worse clinical outcomes in children undergoing surgery for CHD at UCSF, a resource-abundant institution. There is an inverse correlation between total body fat mass and BNP levels. Duration of inotropic support and BNP increase concomitantly as measures of nutritional status decrease, supporting the hypothesis that malnourishment is associated with decreased myocardial function.

Course, predictors of diaphragm recovery after phrenic nerve injury during pediatric cardiac surgery.

BACKGROUND: Hemidiaphragm paralysis from phrenic nerve injury is a known complication of congenital cardiac surgery. Return of diaphragm function has been reported; however, prior studies on this subject have been limited by small numbers, static assessment methods, or observation of plicated or non-plicated patients alone. To describe return of function, we reviewed fluoroscopy and ultrasonography in all diagnosed cases of diaphragmatic paralysis. METHODS: Surgical cases at our institution between 1991 and 2010 were identified for patients with postoperative hemidiaphragm paralysis diagnosed by chest X-ray, ultrasound, or fluoroscopy. Follow-up ultrasound and fluoroscopic studies were reviewed for return of diaphragm function. RESULTS: Seventy-two cases of postoperative hemidiaphragm paralysis were identified. Forty cases were plicated prior to discharge. Plicated patients were younger at time of diagnosis (median 46 days average 3.6 months; p=0.025) and had a larger proportion of single ventricle diagnoses (48% vs 16%) compared with non-plicated patients. Twenty-six patients with paralysis were excluded in follow-up due to lack of studies documenting diaphragm function after the diagnostic study. Of the remaining 46 cases, median follow-up was 353 days (range: 6 days to 17 years). Plicated and non-plicated patients regained function at similar frequency (60% and 54.8%, respectively). Plication status, Risk Adjustment for Congenital Heart Surgery (RACHS) 1 score, age at diagnosis, and side of paralysis did not predict failure of recovery. CONCLUSIONS: In the current era, return of diaphragm function after phrenic nerve injury sustained during congenital cardiac surgery is a known occurrence; however, predicting recovery continues to be difficult.

Brain injury and development in newborns with critical congenital heart disease.

OBJECTIVE: To determine the relationship between radiologically identifiable brain injuries and delayed brain development as reflected by brain metabolic and microstructural integrity. METHODS: Term newborns with congenital heart disease (CHD) (120 preoperatively and 104 postoperatively) were studied with MRI to determine brain injury severity (BIS), microstructure reflected by fractional anisotropy (FA) and average diffusivity (Dav), and metabolism reflected by N-acetylaspartate (NAA)/choline (Cho) and lactate/Cho. Brain development is characterized by increasing NAA/Cho and white matter FA, and by decreasing Dav and lactate/Cho. RESULTS: Newly acquired brain injury was common (41% preoperative, 30% postoperative). Lower white matter FA (p = 0.005) and lower NAA/Cho (p = 0.01) were associated with increasing preoperative BIS. Higher neonatal illness severity scores (p = 0.03), lower preoperative oxygen saturation (p = 0.002), hypotension (p < 0.001), and septostomy (p = 0.002) were also predictive of higher preoperative BIS. Preoperative FA, Dav, and NAA/Cho did not predict new postoperative BIS. Increasing preoperative BIS predicted higher postoperative Dav (p = 0.002) and lactate/Cho (p = 0.008). Within the postoperative scan, new brain injuries were associated with lower white matter FA (p = 0.04). Postoperative BIS (new lesions) was associated with lower postoperative systolic (p = 0.03) and mean (p = 0.05) blood pressures. CONCLUSIONS: Brain injuries in newborns with CHD are strongly related to abnormalities of brain microstructural and metabolic brain development, especially preoperatively. Both newly acquired preoperative and postoperative brain injuries are related to potentially modifiable clinical risk factors.

Single-ventricle anatomy predicts delayed microstructural brain development.

BACKGROUND: Term newborns with congenital heart disease (CHD) show delayed brain development as early as the third trimester, especially in single-ventricle physiology (SVP). Mechanisms causing delayed brain development in CHD are uncertain but may include impaired fetal brain blood flow. Our objective was to determine if cardiac anatomy associated with obstruction to antegrade flow in the ascending aorta is predictive of delayed brain development as measured by diffusion tensor imaging and magnetic resonance spectroscopic (MRS) imaging. METHODS: Echocardiograms from 36 term newborns with SVP were reviewed for the presence of aortic atresia and the diameter of the ascending aorta. Quantitative magnetic resonance imaging parameters measuring brain microstructural (fractional anisotropy (FA) and average diffusivity (Dav)) or metabolic development (N-acetylaspartate (NAA) and lactate/choline (Lac/Cho)) were recorded. RESULTS: Increasing NAA/Cho and white matter (WM) FA, and decreasing Dav and Lac/Cho characterize normal brain development. Consistent with the hypothesis that delayed brain development is related to impaired brain perfusion, smaller ascending aortic diameter and aortic atresia were associated with higher Dav and lower WM FA. Echocardiogram variables were not associated with brain metabolic measures. CONCLUSIONS: These observations support the hypothesis that obstruction to fetal cerebral blood flow impairs brain microstructural development.

Differential responses of the right ventricle to abnormal loading conditions in vivo: possible pathophysiologic mechanisms.

OBJECTIVE: The right ventricle (RV) demonstrates differential adaptations in response to pressure versus volume loading, a phenomenon that may be important in the management of children and adults with congenital heart disease (CHD). The purpose of this study is to elucidate possible transcriptional mechanisms of the RV response to pressure versus volume loading in vivo. METHODS: Fetal lambs had aortopulmonary shunting or pulmonary artery (PA) banding. Four weeks after spontaneous delivery, ovine hearts were evaluated for hemodynamic changes and changes in expression of sarcomeric gene proteins and transcriptional factors. Western blot densitometry and chromatin immunoprecipitation were applied using standard techniques. Transactivation assays were performed using transient transfections in Schneider's Drosophila line 2 cells in culture. RESULTS: After PA banding, the RV pressure increased from 36 ± 4 mm Hg (n = 4) to 96 ± 8 mm Hg (n = 4, P < .05). The RVs of shunted and banded animals showed significant increases in the expression levels and promoter binding of activators myocyte enhancer factor 2, GATA-4, Nkx2.5, transcriptional enhancer factor 1, and specificity protein (Sp) 1. The transcriptional repressor Sp3 was downregulated in shunted animals, but its expression was increased paradoxically in the RV of the PA band group. Immunoprecipitation of Sp3 showed posttranslational modification to the acetylated isoform. In transient transfections of Schneider's Drosophila line 2 cells, acetylation of Sp3 converted it from a transcriptional repressor to an activator. CONCLUSIONS: Posttranslational modifications of the transcriptional repressor Sp3, by acetylation, may be an important mechanism in the differential response of the RV to abnormal loading conditions. Sp3 may serve as a biomarker for RV failure for various heart defects in children and adults with CHD. These findings may have therapeutic implications in the management of right heart failure.

Tezosentan increases nitric oxide signaling via enhanced hydrogen peroxide generation in lambs with surgically induced acute increases in pulmonary blood flow.

We have previously shown that acute increases in pulmonary blood flow (PBF) are limited by a compensatory increase in pulmonary vascular resistance (PVR) via an endothelin-1 (ET-1) dependent decrease in nitric oxide synthase (NOS) activity. The mechanisms underlying the reduction in NO signaling are unresolved. Thus, the purpose of this study was to elucidate mechanisms of this ET-1-NO interaction. Pulmonary arterial endothelial cells were acutely exposed to shear stress in the presence or absence of tezosentan, a combined ET(A) /ET(B) receptor antagonist. Shear increased NO(x) , eNOS phospho-Ser1177, and H(2) O(2) and decreased catalase activity; tezosentan enhanced, while ET-1 attenuated all of these changes. In addition, ET-1 increased eNOS phospho-Thr495 levels. In lambs, 4 h of increased PBF decreased H(2) O(2) , eNOS phospho-Ser1177, and NO(X) levels, and increased eNOS phospho-Thr495, phospho-catalase, and catalase activity. These changes were reversed by tezosentan. PEG-catalase reversed the positive effects of tezosentan on NO signaling. In all groups, opening the shunt resulted in a rapid increase in PBF by 30 min. In vehicle- and tezosentan/PEG-catalase lambs, PBF did not change further over the 4 h study period. PVR fell by 30 min in vehicle- and tezosentan-treated lambs, and by 60 min in tezosentan/PEG-catalase-treated lambs. In vehicle- and tezosentan/PEG-catalase lambs, PVR did not change further over the 4 h study period. In tezosentan-treated lambs, PBF continued to increase and LPVR to decrease over the 4 h study period. We conclude that acute increases in PBF are limited by an ET-1 dependent decrease in NO production via alterations in catalase activity, H(2) O(2) levels, and eNOS phosphorylation.

Pulmonary interstitial glycogenosis: an unrecognized etiology of persistent pulmonary hypertension of the newborn in congenital heart disease?

BACKGROUND: Pulmonary interstitial glycogenosis (PIG) arises from a developmental disorder of the pulmonary mesenchyme and presents clinically with reversible neonatal respiratory distress and/or persistent pulmonary hypertension of the newborn (PPHN). OBJECTIVE: We report two cases of PIG in patients with congenital heart disease (CHD) and evidence of PPHN. RESULTS: Both cases demonstrated the hallmark PIG histologic finding of diffuse, uniform interstitial thickening due to the presence of immature interstitial cells containing abundant cytoplasmic glycogen. CONCLUSIONS: We report the second and third patients with PIG associated with CHD. Because histologic examination is required to establish the diagnosis, we speculate that PIG, although rare, may be underrecognized in neonates presenting with PPHN in the setting of CHD.

Rosiglitazone preserves pulmonary vascular function in lambs with increased pulmonary blood flow.

BACKGROUND: Pulmonary vascular function is impaired with increased pulmonary blood flow (PBF). We hypothesized that a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist would mitigate this effect. METHODS: An aorta-to-pulmonary-artery shunt was placed in 11 fetal lambs. Lambs received the PPAR-γ agonist rosiglitazone (RG, 3 mg/kg/d, n = 6) or vehicle (n = 5) for 4 wk. Lung tissue from five normal 4-wk-old lambs was used for comparisons. RESULTS: At 4 wk, pulmonary artery pressure (PAP) and vascular resistance (PVR) decreased with inhaled nitric oxide (NO) in RG- and vehicle-treated shunt lambs. PAP and PVR decreased with acetylcholine (Ach) in RG-treated, but not vehicle-treated, shunt lambs. In vehicle-treated shunt lambs, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, rac1, superoxide, and 3-nitrotyrosine (3-NT) levels were increased, and Ser1177 endothelial NO synthase (eNOS) protein was decreased as compared with normal lambs. In RG-treated shunt lambs, NOx, Ser1177 eNOS protein, and eNOS activity were increased, and NADPH activity, rac1, superoxide levels, and 3-NT levels were decreased, as compared with vehicle-treated shunt lambs. PPAR-γ protein expression was lower in vehicle-treated shunt lambs than in normal and RG-treated shunt lambs. CONCLUSION: The PPAR-γ agonist RG prevents the loss of agonist-induced endothelium-dependent pulmonary vascular relaxation in lambs with increased PBF, in part, due to decreased oxidative stress and/or increased NO production.

Size of the right ventricle-to-pulmonary artery conduit impacts mid-term outcome after the Norwood procedure in patients weighing less than 3 kg.

OBJECTIVE: The optimal shunt size for patients who have the Norwood operation with a right ventricle-to-pulmonary artery conduit is controversial. The goal of this study is to compare outcomes of 2 shunt sizes in this population. METHODS: Between 2002 and 2010, 75 consecutive patients diagnosed with hypoplastic left heart syndrome and its variants underwent the Norwood procedure with a right ventricle-to-pulmonary artery conduit. The outcomes of 20 neonates weighing <3 kg were analyzed. RESULTS: The cumulative 30-day stage 1 survival [corrected] was 97% (95% confidence interval, 88%-99%) for all patients (73/75), 20 of whom weighed <3 kg. Nine patients had a 6-mm (group 1) and 11 patients had a 5-mm (group 2) right ventricle-to-pulmonary artery conduit. Thirty-day stage 1 survival was 88% (8/9) in group 1 and 90% (10/11) in group 2 (P = .88). The central pulmonary artery confluence size at prebidirectional cavopulmonary shunt catheterization was 4.5 ± 1.2 mm in group 1 and 2.5 ± 1.0 mm in group 2 (P = .009). The mean transpulmonary gradient was higher in group 2 (7.8 ± 3.1 mm Hg vs 4.2 ± 1.9 mm Hg; P = .036). The incidence of pulmonary artery intervention was 16% (1/7) in group 1 and 75% (6/8) in group 2 (P = .030). Survival rate at 6 months was 66% (6/9) in group 1 and 70% (7/10) in group 2 (P = .89). CONCLUSIONS: Use of a 6-mm right ventricle-to-pulmonary artery conduit showed better central pulmonary artery growth and less need for pulmonary artery intervention in the authors' experience.

Prenatal diagnosis of atrial restriction in hypoplastic left heart syndrome is associated with decreased 2-year survival.

OBJECTIVE: To compare the course of hypoplastic left heart syndrome (HLHS) patients diagnosed prenatally with any degree of atrial restriction with those without evidence of atrial restriction. DESIGN: Retrospective, cohort. METHODS: Prenatally diagnosed HLHS patients from August 1999 to January 2009 were categorized as nonrestrictive versus restrictive, defined by left atrial hypertension on pulmonary venous Doppler and/or an intact interatrial septum. RESULTS: Of 73 total fetal patients identified, 49 were live-born. Survival at 2 years was 29/35 [83% confidence interval (CI): 59.5%-88.9%] for the nonrestrictive group and 6/14 (43% CI: 17.7%-6.0%) for the restrictive group (p<0.0001). Of those who underwent stage 1 palliation (35 with nonrestrictive and 10 with restrictive atrial septa), both groups had a similar incidence of preoperative acidosis and need for ventilation and inotropic support. Postoperatively, there was no difference between groups in ventilator days, length of stay, or survival to discharge. There was decreased survival at 2 years in the restrictive group, 60% (CI: 26.2%-87.8%) versus 83% (CI: 66.4%-93.4%) in the nonrestrictive group. Furthermore, a disproportionate number of interstage deaths was evident in the restrictive group. CONCLUSIONS: Prenatal presence of any degree of atrial septal restriction in the setting of HLHS confers a significant survival disadvantage, with increases in both early and late mortality.

Surgical management of left ventricular outflow tract obstruction.

BACKGROUND: Left ventricular outflow tract obstruction (LVOTO) is caused by a spectrum of lesions. This study was performed to determine the outcomes of surgical management of LVOTO. METHODS: All patients who had surgery of the LVOT between 2002 and 2010 were retrospectively reviewed. RESULTS: There were 103 consecutive patients with median age 6.8 years (range 8 days to 62 years). Fourteen patients had simple subaortic membrane. Eighty-nine patients had complex LVOTO including fibromuscular obstruction (n = 53), tunnel obstruction (n = 22), hypertrophic cardiomyopathy/muscular obstruction (n = 15), and anomalies of the mitral subvalvar apparatus (n = 13). There were no early deaths. Mean LVOT gradient decreased from 33 mmHg (range 1 to 108 mmHg) to 6 mmHg (range 0 to 45 mmHg) (p < 0.001). Median follow-up was 3.8 years (range 0.9 to 8.5 years). There were three late deaths. Cumulative survival at one, three, and five years was 96% (95% CI 89% to 99%). All patients are in New York Heart Association classes I-II. Ten patients required reoperation (three for recurrent/residual LVOTO). Freedom from reoperation was 94%, 90%, and 78% at one, three, and five years (95% CI 86% to 98%, 80% to 95%, and 59% to 89%, respectively). No patient with complex LVOTO who had release of the fibrous trigones required reoperation [0% (0/26) vs. 16% (10/63) (p = 0.031)]. Factors associated with increased reoperation risk were interrupted aortic arch (OR 6.4, p = 0.22), atrioventricular septal defect (OR 15.4, p = 0.008), and higher mean LVOT gradient at discharge (OR 1.08, p = 0.023). CONCLUSIONS: Utilizing a multitude of operative strategies for surgery of the LVOT results in favorable early and midterm outcomes. Residual LVOTO and original cardiac diagnosis are associated with increased reoperation risk. Release of the fibrous trigones decreases reoperation risk in patients with complex LVOTO.

Prenatal diagnosis of hypoplastic left heart syndrome in current era.

We sought to evaluate the relation of a prenatal diagnosis (preDx) with morbidity and mortality during the initial hospitalization in a contemporary cohort of patients with hypoplastic left heart syndrome (HLHS). A retrospective study of patients with HLHS presenting from 1999 to 2010 was performed. Patients with genetic disorders or a gestational age <34 weeks or who had intentionally received comfort care only were excluded. Of the 81 patients meeting the study criteria, 49 had a preDx and 32 were diagnosed postnatally (postDx). Birth weight (median 3.0 vs 3.4 kg; p = 0.007) and gestational age (median 38 vs 39 weeks; p <0.001) were lower in the preDx than in the postDx patients. Preoperatively, the postDx patients were intubated more frequently (97% vs 71%, p = 0.004) and ventilated longer (median 96 vs 24 hours, p = 0.005) than the preDx patients. They also had more preoperative acidosis, multiorgan failure, tricuspid valve regurgitation, and right ventricular dysfunction. Of the 73 patients undergoing surgery, no difference in survival was seen between the preDx and postDx groups (91% vs 89%). The median duration of postoperative ventilation was 7 days and the median length of stay was 36 days for the 66 survivors, with no difference between the 2 groups. Postoperative morbidities, including chylothorax and infection, were also similar in the preDx and postDx patients. No studied preoperative factor was associated with death, duration of postoperative ventilation, or length of stay. In conclusion, our recent experience has shown that preDx of HLHS was not associated with a survival advantage, fewer postoperative complications, or shorter length of stay. Improved preoperative status was observed in the preDx patients; however, they were born earlier with a lower birthweight. What effect these factors might have on longer term morbidity remains unknown.

Early outcomes of primary sutureless repair of the pulmonary veins.

BACKGROUND: The "sutureless" repair technique has improved outcomes for post-repair pulmonary vein (PV) stenosis. The purpose of this study is to determine the early outcomes of primary sutureless repair of pulmonary venoocclusive disease in infants with congenital PV stenosis-hypoplasia or PVs at high risk for progressive stenosis. METHODS: This is a retrospective review of infants who had primary sutureless repair of the PVs from October 2002 to April 2010. RESULTS: Twenty-five infants had primary sutureless repair of the PVs. Eighteen infants had total anomalous pulmonary venous return; 14 with obstruction, 10 with heterotaxy syndrome, and 9 with univentricular anatomy. Seven infants had congenital PV stenosis. There were 24 perioperative survivors (96%; 95% confidence interval [CI], 75% to 99%) and 2 late deaths from extracardiac causes. Follow-up was available on 21 out of 22 survivors at a median duration of 34 months (range, 9 to 100 months). Persistence-recurrence of PV stenosis occurred in 3 veins (3%) of 2 infants (8%). On follow-up echocardiography, right ventricular systolic pressure was normal in 13 out of 14 infants with a biventricular heart and 60% of systemic blood pressure in 1 infant. Kaplan-Meier 1-year cumulative survival was 88% (95% CI, 66% to 96%). Kaplan-Meier cumulative disease-free survival was 96% (95% CI, 75% to 99%) at 30 days and 84% (95% CI, 58% to 95%) at 1 year. By Cox proportional hazards, age, univentricular anatomy, and atrial isomerism-heterotaxy syndrome were not associated with an increased risk of death or persistence-recurrence. One-year disease-free survival was lower in infants with prematurity (p=0.0055) and low birth weight (p=0.0011). CONCLUSIONS: Primary sutureless repair is a feasible, safe, and relatively effective method of addressing congenital PV stenosis and (or) high-risk PVs, particularly in infants with single ventricle anatomy and (or) heterotaxy syndrome.