Norwood Procedure Research Articles

Abnormal torsion and helical flow patterns of the neo-aorta in hypoplastic left heart syndrome assessed with 4D-flow MRI.

The Norwood procedure is the first stage of correction for patients with hypoplastic left heart syndrome (HLHS) and may lead to an abnormal neoaortic anatomy. We prospectively studied the neoaorta's fluid dynamics and the abnormal twist of the neoaorta by MRI examinations of HLHS patients in Fontan circulation. This study for the first time investigates the hypothesis that the neoaorta twist is associated with increased helical flow patterns, which may lead to an increased workload for the systemic right ventricle (RV) and ultimately to RV hypertrophy. A group of forty-two HLHS patients with a median age of 4.9 (2.9-17.0) years, at NYHA I was studied along with a control group of eleven subjects with healthy hearts and a median age of 12.1 (4.0-41.6). All subjects underwent MRI of the thoracic aorta including ECG-gated 2D balanced SSFP cine for an axial slice stack and 4D-flow MRI for a sagittal volume slab covering the thoracic aorta. The twist of the neoaortic arch was quantified by the effective geometric torsion, defined as the product of curvature and geometric torsion. Fluid dynamics and geometry in the neoaorta, including the flow helicity index, were evaluated using an in-house analysis software (MeVisLab-based). Myocardial mass of the systemic ventricle at end-diastole was estimated by planimetry of the short-axis stack. Compared to the control group, the neoaorta in the HLHS patients shows an increased twist (P=0.04) and higher peak helicity density (P=0.03). The maximum helicity density was correlated with maximum effective torsion of the ascending neoaorta (P<0.001). The degree of maximum twist correlated with the increase in RV myocardial mass (P<0.01). This study shows that the abnormal twist of the neoaortic arch in HLHS patients is associated with abnormal helical flow patterns, which may contribute to increased RV afterload and may adversely affect the systemic RV by stimulation of myocardial hypertrophy. These findings suggest that further improvements of surgical aortic reconstruction, guided by insights from 4D-flow MRI, could lead to better neoaortic fluid dynamics in patients with HLHS.

Can plastic be better than biological? What is the best material for reconstruction of the aortic arch in the Norwood procedure?

Can plastic be better than biological? What is the best material for reconstruction of the aortic arch in the Norwood procedure?

Influence of Shunt Type on Survival and Right Heart Function after the Norwood Procedure for Aortic Atresia

The study objective was to compare the results after Norwood procedure between modified Blalock-Taussig shunt (MBTS) and right ventricle-to-pulmonary artery conduit (RVPAC) according to Sano in patients with hypoplastic left heart syndrome (HLHS) and aortic atresia (AA). A total of 146 neonates with HLHS and AA who underwent the Norwood procedure at our institution between 2001 and 2020 were divided into 2 groups according to shunt type (MBTS or RVPAC). Survival after the Norwood procedure was compared between the groups. Longitudinal right ventricular and tricuspid valve function in each group were evaluated using cubic splines method. RVPAC was performed in 103 patients and MBTS in 43 according to surgeon preference. There were no differences in the 30-day mortality rates (16.5% vs 16.3%, P =0.973). Survival at 0.5, 1 and 3 years was 79.6%, 74.6%, and 68.9% in RVPAC and 66.8%, 64.3%, and 58.5% in MBTS (P = 0.293). Among 23 patients undergoing tricuspid valve procedure, different mechanisms of tricuspid regurgitation were observed between the groups. Longitudinal analysis revealed greater prevalence of late right ventricular dysfunction in RVPAC patients. In 77 patients who completed Fontan procedure, the postoperative N-terminal pro B-type natriuretic peptide value was significantly higher in RVPAC vs MBTS (554 vs 276 ng/L, P = 0.007). No survival advantage of RVPAC over MBTS was observed in neonates with HLHS and AA undergoing the Norwood procedure. Longitudinal analysis demonstrated a greater prevalence of right ventricular dysfunction and higher N-terminal pro B-type natriuretic peptide values during late follow-up in patients with RVPAC.

Abstract 13689: The Center-Volume Effect on Congenital Heart Surgery Revised: Is It Time to Consider Regionalization of Care?

Introduction: Regionalization of congenital heart surgery (CHS) has been debated in the U.S. and other countries. Previous reports demonstrated a variable effect of a center’s volume on in-hospital postoperative mortality. However, the volume-outcome relationship for CHS remains incompletely understood without considering outcomes beyond hospital discharge. Hypothesis: We sought to determine, whether procedure-specific center volume predicts postoperative mortality for infants undergoing three complex benchmark procedures (Norwood procedure, arterial switch operation and complete atrioventricular canal repair) and used ventricular septal defect (VSD) closure as a simple benchmark procedure comparison. Methods: We used data from the Pediatric Cardiac Care Consortium, a multi-center U.S.-based clinical registry of CHS, enriched with post-discharge death data after linkage with the National Death Index. We used generalized estimating equations to assess the association between procedure-specific volume and mortality from the time of CHS and up to three years after CHS. Models were adjusted for patient age and weight at CHS, presence of a chromosomal abnormality, and surgical era and accounted for clustering at the center-level. Results: Analysis included 6,656 infants operated at 42 centers between 1982 and 2003. We found an absolute reduction in post-operative risk of death ranging from 6-12% for every additional surgery performed in the same center for Norwood, ASO, and CAVC repair and at all time points examined (Table). There was no statistically significant association between VSD center volume and mortality at any time point. Conclusions: In-hospital and longer-term survival after infantile CHS is improved with increased center case volume for complex CHS. These findings support the regionalization of complex CHS in the U.S.. Decision-makers should consider feasibility of such regionalization to improve outcomes after complex CHS.

Abstract 12078: Pre-Glenn Aorto-Pulmonary Collaterals and Its Impact on Outcomes in Single Ventricle Patients

Introduction: In single-ventricle patients undergoing bi-directional Glenn (BDG), 36-59% have angiographically detectable aorto-pulmonary collateral (APC) flow. However, predictors, hemodynamic and clinical outcomes are unknown. Hypothesis: We hypothesize that (a) shunt type, hemodynamic findings at the pre-Glenn catheterization predict pre-BDG APC burden and (b) APC burden at BDG catheterization may predict post BDG death/transplantation, pulmonary artery (PA) or APC intervention. Methods: Retrospective cohort study of patients following Norwood Procedure for single ventricle anatomy. Covariates included demographics; clinical and hemodynamic at Pre-BDG catheterization. APC burden at pre-BDG catheterization was assessed dichotomously by a single reader (moderate/severe vs. none/mild). Logistic regression was used to identify predictors of APC burden and Cox regression for time to clinical outcomes. Results: Among 104 patients, 89.4% (n=93/104) underwent pre-BDG catherization, of which 55% (n=51/93) had APC intervention and 91% (n=85/93) progressed to BDG. Post-BDG, 60% (n=51/85) had no/mild and 40% (n=34/85) had moderate/severe APC burden. Within 36 months, APC intervention occurred in 74% (n=69/63) with no difference between groups (84% vs. 79%, Logrank 0.75). Predictors of APC burden were male sex (OR 3.59; 95% CI 1.18-10.98), older age at BDG (1.02 per year; 1.01-1.04), PA saturations (1.80;1.18-2.75), and Qp:Qs ratio (OR 1.23 per 0.10 unit increase;1.08-1.41). APC burden is not predictive of death/transplantation or future APC intervention but may show a trend towards future PA intervention (HR 2.11, 95% CI 0.98-4.52, p=0.056)(Figure 1). Sano shunt is a predictor of APC intervention following BDG (HR 2.07, 95%CI 1.09-3.90, p=0.03). Conclusions: Moderate or severe APC burden was present in 40% after stage I Norwood and QP:QS is a strong predictor for APC burden; patients with moderate/severe APC’s may be at higher risk of PA interventions.

Abstract 9565: Quantitative Assessment of Neonatal Brain Perfusion by Ultrafast Power Doppler in the Operating Room

Introduction: The main challenge with cardiopulmonary bypass (CPB) surgery in newborns with congenital heart disease is to prevent ischemic brain injury impacting on the long-term neurodevelopmental outcomes. To date, no quantitative method is available to adapt the CBP parameters for optimal per-operative cerebral perfusion. Ultrafast power Doppler (UPD) is a new portative bedside technique to map and quantify cerebral perfusion. Our objective was to evaluate UPD for quantifying the variation of cerebral perfusion in neonates during CBP surgery. Methods: UPD was performed in 5 newborns with hypoplastic left heart syndrome undergoing a Norwood procedure and 5 age-matched healthy newborns. Using a 6.9 MHz linear array probe (11L, General Electric) connected to a programmable and portable ultrafast ultrasound scanner (Vantage 256, Verasonics Inc.), via a transfontanellar approach, six pre-defined brain imaging planes were acquired in sagittal and coronal views. Assessments were performed pre-operatively, during various perfusions states intra-operatively and 24-48 hours post-operatively. Global and regional cerebral blood volume (CBV) and resistivity index (RI) maps from UPD were obtained. Results: The baseline brain perfusion was the same for both groups (p=0.62). During CPB, whole brain and regional CBV decreases more than 50% compared to baseline and reaching approximately 25% of initial CBV during selective brain perfusion and during the final stages of bypass (Figure). RI maps shows intermittent overall decrease of vascular resistivities below 0.5 on bypass and selective brain perfusion before returning to baseline in post-op, reflecting an overall decrease of the cerebral vascular resistance during CPB. Conclusions: UPD demonstrates variation in cerebral vascular resistance and blood volume in neonates undergoing CPB surgery. UPD paves the road for optimization of CPB parameters in neonates undergoing cardiac surgery.

Complications After Surgical Repair of Congenital Heart Disease in Infants. An Experience From Tertiary Care Center.

ObjectivesThis study aimed to describe the incidence and spectrum of postoperative complications in infants who underwent their first cardiac surgery for the repair of congenital heart diseases.MethodsThis is a single-center retrospective study. Data of infants admitted to King Faisal Specialist Hospital & Research Center; Jeddah; Saudi Arabia, from January 2015 to December 2019 who underwent the first cardiac procedure for congenital heart disease at an age of less than 3 months, were analyzed. The primary outcome is the prevalence and spectrum of postoperative complications during hospitalization. Data were analyzed by using descriptive and analytical statistics using SAS software version 9.4.ResultsData of 130 procedures were analyzed. The most frequent procedure performed was the Norwood procedure (31.5%), aortic coarctation repair (13.8%), arterial switch operation (13%), and Blalock-Taussig and central shunts (10%). The overall postprocedural complications were reported in 96 (73.8%) of the procedures. The most frequent complications were prolonged postoperative mechanical ventilation (27%), pleural effusion (21%), excessive bleeding (19%), cardiac arrest (18%), and systemic infections (18%).ConclusionCardiac surgery for congenital heart disease in young infants has a substantial risk for postoperative complications. The high incidence of these complications in these cases makes necessary attention to prove the outcomes in the cardiac centers.

Aortic arch reconstruction in the Norwood procedure using a curved polytetrafluorethylene patch.

The aortic arch enlargement in the Norwood procedure is classically carried out using a curved homograft patch on the inner curvature of the neoaortic arch. The study investigates the outcome of a newly used artificial patch from a vascular prosthesis as an alternative to a homograft patch. Since April 2007, we used curved polytetrafluorethylene (PTFE) patches cut out of a prosthesis as an alternative to homograft patches for the aortic arch reconstruction. The decision for either patch material was made due to anatomic reasons, preferring PTFE patches in larger aortas. In this study, 224 Norwood patients, operated between April 2007 and April 2018, were analysed. A total of 104 patients received a PTFE patch (group PTFE), and 120 patients got a pulmonary homograft patch (group homograft). A single-centre retrospective analysis was carried out concerning postoperative course and long-term follow-up regarding aortic arch interventions and reoperations and comparing the 2 material groups. There were no material associated operative or postoperative complications. In-hospital mortality was 13% in group PTFE. Six children died late during follow-up (6%). One aortic isthmus dilatation (1%) was carried out 12 months after the Norwood procedure in this group, no arch reoperation was necessary during the complete follow-up. The curved PTFE patch showed good qualities in operative technical demands and excellent long-term results. In selected cases of hypoplastic left heart syndrome, it can be well used as alternative to the pulmonary homograft.

Estimating the optimal timing of surgery by imputing potential outcomes.

Hypoplastic left heart syndrome is a congenital anomaly that is uniformly fatal in infancy without immediate treatment. The standard treatment consists of an initial Norwood procedure (stage 1) followed some months later by stage 2 palliation (S2P). The ideal timing of the S2P is uncertain. The Single Ventricle Reconstruction Trial (SVRT) randomized the procedure used in the initial Norwood operation, leaving the timing of the S2P to the discretion of the surgical team. To estimate the causal effect of the timing of S2P, we propose to impute the potential post-S2P survival outcomes using statistical models under the Rubin Causal Model framework. With this approach, it is straightforward to estimate the causal effect of S2P timing on post-S2P survival by directly comparing the imputed potential outcomes. Specifically, we consider a lognormal model and a restricted cubic spline model, evaluating their performance in Monte Carlo studies. When applied to the SVRT data, the models give somewhat different imputed values, but both support the conclusion that the optimal time for the S2P is at 6months after the Norwood procedure.

Norwood Procedure in a Patient With Hypoplastic Left Heart Syndrome, Right Aortic Arch, and Right Descending Aorta.

We describe the surgical treatment of a patient with hypoplastic left heart syndrome and right aortic arch.

The Role Of Shunt In The Norwood Procedure

Objectives: In this study we observed that the effect of post-Norwood 3.5 mm modified BTS(mBTS and 5 mm right ventricle to pulmonary (Sano modification) shunt models on clinical outcomes. Patients and Methods: 54 patients who were operated in our hospital between 2011and 2020 years, were included in our study and this is a retrospective, observational, single-center case series study. Results: The effect of shunt type on mortality was statistically significant, and the rate of death was lower in patients who used SANO type shunts. (p &lt;0.05) The effect of VISC score on early mortality was significant, and VISC score was higher in the group with exitus. (p &lt;0.05). Conclusion: Although Sano shunt seems more preferred in Norwood, the experience of the surgeon and the center's experience may have led to variation in results at HLHS. Nevertheless, it will be clinically important for studies to evaluate the long-term results between the two shunt types.

The Importance of Gestational Age as a Prognostic Factor on Norwood Stage 1 Outcome

Introduction: The Norwood operation performed for hypoplastic left heart syndrome in the neonatal period remains to be a high-risk and difficult surgical procedure. It is known that preterm birth often accompanied by low birth weight is associated with high mortality and morbidity in these patients. Patients and Methods: The study included 54 patients who underwent the Norwood procedure in our clinic in the period between December 2012 and December 2019. Patient data were evaluated retrospectively; in- cluding gestational week, age, body weight, total bypass time, aortic cross-clamp time, extubation time, the length of stay in the intensive care unit, the length of hospital stay, and the preoperative and postoperative levels of urea, creatinine, alanine aminotransferase, aspartate aminotransferase, and platelet counts. Results: The body weight of the patients ranged from 2350 to 4500 grams with an average of 3296.3 ± 486.7 grams. The age of the patients at the time of operation ranged from 1 to 374 days with an average of 30.31 ± 70.51 days. The comparison of patients by term pregnancies resulted in no statistically significant differences but the comparison by gestational weeks revealed a statistically significant result. Conclusion: Preoperative risk factors affect prognosis more than the surgical technique and the treatment approach in patients with a functional single ventricle. When the gestational week was evaluated as a preop- erative risk factor for its effects on the postoperative prognosis of stage 1 Norwood operation in our study, it was found that mortality decreased significantly after the 38.8th gestational week (272 gestational days).

Incidence and Recovery of Vocal Fold Immobility Following Pediatric Cardiac Operations.

Loss of laryngeal function after congenital cardiac surgery causes morbidity and prolongs hospitalization. Early diagnosis of vocal fold immobility (VFI) and referral to pediatric otolaryngology (pOTO) aids in laryngeal rehabilitation. Understanding the incidence and recovery rates of VFI enables counseling for families of infants undergoing high-risk surgery. A retrospective chart review from November 2014 to July 2019 of infants postcardiac surgery where the aortic arch or surrounding structures were manipulated and were screened via flexible fiberoptic laryngoscopy (FFL) at a single institution was performed. Patients were divided into five surgical categories: Norwood procedure, aortic arch augmentation via median sternotomy, arterial switch operation, coarctation repair via lateral thoracotomy, and cardiac surgeries including ligation of a patent ductus arteriosus (PDA). Patients undergoing isolated PDA ligation were excluded. One hundred ninety-nine qualifying operations occurred during this period; 28 patients did not undergo FFL before discharge and were excluded from the analysis. Immediately following cardiac surgery, 34% (58 of 171 patients) had VFI. Follow-up was completed by 38 of 58 patients with VFI. Complete recovery was demonstrated in 63% (24 of 38) of patients by 6 months and in 86% (33 of 38) within 18 months. The highest risk occurred with the Norwood procedure and arch augmentation via median sternotomy. Infants undergoing surgery involving the aortic arch and surrounding structures have high rates of VFI. Follow-up by pOTO is recommended to optimize laryngeal rehabilitation. Most patients have spontaneous recovery within 18 months of cardiac surgery.

Does the size of pulmonary artery impact on recoarctation of the aorta after the Norwood procedure without patch?

This study aimed to evaluate whether recoarctation of the aorta (reCoA) after the Norwood procedure for hypoplastic left heart syndrome correlates with pre- and postoperative anatomic factors. This retrospective study included 48 patients who underwent Norwood procedure with right ventricle-to-pulmonary artery conduit between 2009 and 2017. Anatomical factors such as preoperative length, diameter of the main pulmonary artery (MPA), and postoperative neoaortic arch angle stratified by arch reconstruction technique were analysed using the receiver operating characteristic analysis. Eleven patients needed surgical intervention for reCoA at stage 2. Out of the 30 patients who underwent direct anastomosis during arch reconstruction, 7 developed reCoA. Seven patients received the full patch augmentation (patch augmentation for both lesser and greater curvatures) and were all spared from reCoA. Among the patients who had direct anastomosis, the preoperative MPA length was correlated with the postoperative arch angle (P = 0.021) and was associated with the occurrence of reCoA (P = 0.002) and the best cutoff value for MPA length was 10 mm. The postoperative arch angle was also correlated with the incidence of reCoA (P < 0.001) and was larger in patients who underwent the full patch augmentation than in patients who had direct anastomosis (126° vs 112°, P = 0.005) despite comparable MPA length. ReCoA after the Norwood procedure correlates with MPA length when a direct anastomosis was used. Direct anastomosis can be considered in patients with a longer preoperative MPA. In other cases, the full patch augmentation should be considered for obtaining a large and smooth neoaortic arch.

Growth and Nutritional Intake of Infants with Univentricular Circulation

To evaluate the nutritional status and early nutritional intake of infants with univentricular congenital heart disease. The included infants underwent a Norwood procedure or hybrid intervention (stage 1) within the first 6weeks of life, between January 2014 and January 2019, at Children's Health Ireland at Crumlin. Demographic, anthropometric, nutritional intake, and morbidity data were collected. Data were collected on 90 infants and 1886 neonatal admission days. There was a significant drop in mean weight-for-age z-score (WAZ) between measurements at birth, -0.01 and on discharge post stage 1 surgery -1.45 (P<.01). On hospital discharge (median hospital stay, 25days) 32% of infants had a WAZ<-2 and 11% had a WAZ<-3. Pre-stage 1, 26% received trophic feeds and 39% received parenteral nutrition. Basal metabolic requirements and target caloric intake (120kcal/kg) were met on 56% and 13% of admission days, respectively. Infants referred to a dietitian had a shorter time to any form of nutrition support, enteral feeds, and target caloric intake (P<.001, P=.016, and P=.048, respectively). At stage 3 (Fontan) surgery, 15% of infants were classified as stunted (length-for-age z-score [LAZ] <-2). The greatest decline in nutritional status occurs in the neonatal period, followed by significant growth stunting by the time of the Fontan procedure. Early involvement of dietitians is critical in the care of this nutritionally fragile group. With the currently low rate of preoperative nutritional support, there may be opportunities to improve intake at this critical stage.

The impact of a standardized perioperative management on hospital mortality after the Norwood procedure in a low volume center: results and perspectives.

Mortality of newborns with Hypoplastic Left Heart Syndrome (HLHS) is mainly concentrated after Norwood procedure (NP) stage 1 palliation (S1P) and between S1P and stage 2 palliation (S2P). Standardized management of these patients may help to control hospital mortality. Aim of the study was to evaluate the impact on hospital mortality of a standardized perioperative management (SPM) for newborns requiring S1P in a low volume center for NP. A consecutive series of patients undergoing S1P from January 1, 2002 to December 31, 2006 were retrospectively compared, by a "before and after" design, with those receiving a SPM (i.e. use of selective cerebral perfusion, near infrared spectroscopy, delayed sternal closure, modified ultrafiltration) from January 1st, 2007 to December 31st, 2018. Demographic, intraoperative and postoperative characteristics were collected. Univariate and multivariate analyses assessed differences before and after SPM. Ninety-one newborns underwent S1P in the considered period; of 74 eligible patients, 25 did not receive SPM, while 49 received SPM. Hospital mortality after S1P was 31% (CI 21-44%). The introduction of a SPM did not affect hospital mortality both at the univariate-(28% vs. 29%, P=0.959) and at the multivariate analysis (HR 1.85, P=0.62). Mortality was 12% (CI 6-25%) between hospital discharge after S1P and S2P and 8% (CI 3-22%) between S2P and S3P. The use of a SPM for HLHS newborns requiring S1P was not effective in reducing hospital mortality in a low volume center. We suggest a collaboration between Italian Pediatric Cardiac Centers to manage HLHS patients.

Comparison of shunt types in the neonatal Norwood procedure for single ventricle.

The ideal shunt for pulmonary blood flow, modified Blalock-Taussig shunt (MBTS) or right ventricular-pulmonary artery conduit (RVPAC) is yet to be determined. This study aimed to evaluate outcomes after the Norwood procedure according to the type of shunt. A total of 322 neonates with hypoplastic left heart syndrome and related anomalies who underwent the Norwood procedure at our institution between 2001 and 2019 were divided into MBTS and RVPAC groups and the outcomes after the Norwood procedure were compared between the groups with respect to mortality after each staged procedure. We identified 322 consequent patients who underwent neonatal Norwood procedure for hypoplastic left heart syndrome (271 patients, 84.2%) and its variant (51 patients, 15.8%). RVPAC was performed in 163 (50.6%) patients and MBTS was performed in 159 (49.4%). There were no differences in the rate of early death (11.0% vs 12.6%, P = 0.69) or late death (7.4% vs 6.9%, P = 0.87) between the 2 groups after the Norwood procedure, and no significant difference in the number of patients who reached bidirectional cavopulmonary shunt (77.9% vs 76.1%, P = 0.69), and there was no difference in mortality after bidirectional cavopulmonary shunt (12.3% vs 7.5%, P = 0.15) or Fontan completion rate (54.0% vs 52.2%, P = 0.42) between the 2 groups. Survival at 0.5, 1, 3 and 6 years after the Norwood procedure was 81.0%, 73.8%, 67.9% and 67.0% in patients with RVPAC and 77.1%, 73.3%, 69.1% and 67.9% in patients with MBTS. There was no significant difference in the survival between the 2 groups during the median follow-up of 2.6 (interquartile ranges: 0.3-8.4, maximal 18.8) years (P = 0.97). In neonates undergoing the Norwood procedure, our available data of maximal 18.8 years follow-up showed no significant difference in early mortality, inter-stage attritions, or overall survival, between MBTS and RVPAC.

Ascending aortic extension to enlarge the retroaortic space in children after the Norwood procedure.

Left pulmonary artery stenosis is a well-recognized complication following the Norwood procedure. We herein report two cases in which ascending aortic extension was performed to enlarge the retroaortic space in children with left pulmonary artery stenosis after the Norwood procedure. We used graft interposition in the ascending aorta to increase the retroaortic apace and concomitantly performed extended left pulmonary artery reconstruction. This procedure obtains a more balanced distribution of the pulmonary blood flow, which is crucial to achieve good Fontan circulation.

RBC Transfusion Induced ST Segment Variability Following the Norwood Procedure.

Retrospective case-control study. Nine-hundred seventy-three-bed pediatric hospital with a 54-bed cardiovascular ICU. Seventy-three neonates with hypoplastic left heart syndrome following the Norwood procedure, 38 with a Blalock-Taussig shunt and 35 with a right ventricle to pulmonary artery shunt. RBC transfusion. High-frequency physiologic data were captured 30 minutes prior to the initiation of (baseline) and during the 120 minutes of the transfusion. A rate pressure product was calculated for each subject and used as an indicator of myocardial oxygen demand. Electrocardiogram leads (aVL, V1, II) were used to construct a 3D ST segment vector to assess ST segment variability and functioned as a surrogate indicator of myocardial ischemia. One-hundred thirty-eight transfusions occurred in the Blalock-Taussig shunt group and 139 in the right ventricle to pulmonary artery shunt group. There was no significant change in the rate pressure product for either group; however, ST segment variability progressively increased for the entire cohort during the transfusion, becoming statistically significant by the end of the transfusion. Upon subgroup analysis, this finding was noted with statistical significance in the Blalock-Taussig shunt group and trending toward significance in the right ventricle to pulmonary artery shunt group. We found a significant increase in the ST segment variability and evidence of myocardial ischemia temporally associated with RBC transfusions in neonates following the Norwood procedure, specifically among those in the Blalock-Taussig shunt group, which may impact immediate and long-term outcomes.

A milestone in congenital cardiac surgery: Four decades of the Norwood procedure.

Hypoplastic left heart syndrome (HLHS) was first described by Lev in 1952, but it was not until 1958 that it received a name from Noonan and Nadas. For the next several decades, the defect was considered untreatable. In 1979, William Norwood and his colleagues from Boston initiated a program to evaluate staged surgical management for infants with HLHS. The Norwood operation has became a milestone in the effective palliation for neonates born with HLHS. Today, the Norwood procedure is the first step of a three-stage heart surgery aimed at creating a new circulatory pathway (i.e., the Fontan pathway).