The modified Norwood palliation on a beating heart

Norwood Operation with Right Ventricular-Pulmonary Artery Shunt Versus Comprehensive Stage II After Bilateral Pulmonary Artery Banding Palliation

As a strategy for the primary Norwood operation, the right ventricular-pulmonary artery shunt is associated with satisfactory early outcome. However, use of this shunt after bilateral pulmonary artery banding remains controversial. This study compared the operative outcomes and late hemodynamics in patients who underwent the Norwood operation, preceded by bilateral pulmonary artery banding, with a right ventricular-pulmonary artery shunt or with bidirectional Glenn anastomosis (comprehensive stage II strategy). We retrospectively reviewed 38 patients who underwent the Norwood operation preceded by bilateral pulmonary artery banding between 2004 and 2017. Of these, 17 underwent the Norwood operation with a right ventricular-pulmonary artery shunt (Group S), whereas 21 underwent the comprehensive stage II strategy (Group G). 5 years after the Norwood operation, 10 (60%) and 17 (81%) patients in Group S and Group G, respectively, underwent the Fontan procedure. Group S showed significantly lower pressure in the superior vena cava after bidirectional Glenn anastomosis than Group G (13 ± 2 mmHg vs. 18 ± 3 mmHg; p < 0.01), but pressures were similar after the Fontan procedure. The right ventricular end-diastolic volume at 1 year post-Fontan procedure was significantly higher in Group S than in Group G (142 ± 41% vs. 91 ± 28%; p < 0.01). In terms of early outcomes, the Norwood operation with a right ventricular-pulmonary artery shunt enabled low pressure in the superior vena cava, but in the long term, this shunt adversely influenced the right ventricular volume.

Hypoplastic Left Heart Syndrome: Definition, Morphology, and Classification

This manuscript will provide information about hypoplastic left heart syndrome (HLHS) and related malformations, including definitions, morphology, and classification, based on the 2021 International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Revision of the International Classification of Diseases (ICD-11). HLHS is defined as "a spectrum of congenital cardiovascular malformations with normally aligned great arteries without a common atrioventricular junction, characterized by underdevelopment of the left heart with significant hypoplasia of the left ventricle including atresia, stenosis, or hypoplasia of the aortic or mitral valve, or both valves, and hypoplasia of the ascending aorta and aortic arch." Functionally univentricular heart is defined as "a spectrum of congenital cardiac malformations in which the ventricular mass may not readily lend itself to partitioning that commits one ventricular pump to the systemic circulation, and another to the pulmonary circulation." The Norwood operation is synonymous with the term "Norwood (Stage 1)" and is defined as (1) creation of an aortopulmonary connection and neoaortic arch construction resulting in univentricular physiology and (2) creation of a controlled source of pulmonary blood flow with a calibrated systemic-to-pulmonary artery shunt, a right ventricle to pulmonary artery conduit, or rarely, a cavopulmonary connection. The goals of the Norwood (Stage 1) Operation are creation of (1) unobstructed systemic blood flow via aortopulmonary connection and neoaortic arch construction, (2) unobstructed coronary blood flow, (3) unobstructed flow across the atrial septum, and (4) controlled pulmonary blood flow.

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

OBJECTIVES

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Interstage management of pulmonary blood flow after the Norwood procedure with right ventricle-to-pulmonary artery conduit

OBJECTIVES

Our goal was to assess the efficacy of managing pulmonary blood flow from the Norwood procedure with a right ventricle-to-pulmonary artery (RV-PA) conduit until stage 2 palliation (S2P).

METHODS

Among 48 consecutive patients undergoing the Norwood procedure between 2008 and 2018, 40 (83.3%) patients who survived to discharge were included in this study. The primary diagnosis was hypoplastic left heart syndrome in 28 (70%) patients and hypoplastic left heart syndrome variant in 12 (30%) patients. All patients received bilateral pulmonary artery banding. The median age and weight at the time of the Norwood procedure were 41 (25th-75th percentiles: 27-89) days and 3.2 (2.7-3.9) kg, respectively. In keeping with institutional strategy, S2P was undertaken when body weight exceeded 5.0 kg, and normal gross motor development was confirmed.

RESULTS

The RV-PA conduit was clipped in 28 (70%) patients during the perioperative period of the Norwood procedure, then partial unclipping was performed in 8 (20%) patients and full unclipping was performed in 20 (50%) patients. Before S2P, the median pulmonary-to-systemic blood flow ratio was 1.0 (0.7-1.3). The median age and weight at the time of S2P were 10.7 (9.0-12.9) months and 6.3 (5.5-7.1) kg, respectively. The survival rate 5 years after Norwood discharge was 85.3%. Pre-S2P pulmonary-to-systemic blood flow ratio was linearly correlated with greater interstage changes in systemic atrioventricular valve regurgitation (R2 = 0.223, P = 0.004).

CONCLUSIONS

Interstage management of pulmonary blood flow by RV-PA conduit clipping and gradual unclipping provided good interstage outcomes. The median pulmonary-to-systemic blood flow ratio could be controlled to 1.0 at pre-S2P catheter examination.

Cobra-Head Cuffed Vascular Graft as Right Ventricle-to-Pulmonary Artery Shunt in Norwood Procedure

BACKGROUND

Right ventricle-to-pulmonary artery (RV-PA) shunt as a part of the Norwood procedure underwent many modifications. We present our experience with a commercially available polytetrafluoroethylene vascular graft with cobra-head cuff as an RV-PA shunt.

METHODS

A consecutive series of 52 children with hypoplastic left heart syndrome (median age 8 [range, 2-68] days, median weight 3200 [range, 2060-4400] g) underwent the Norwood procedure with a cobra-head cuffed RV-PA shunt (6 mm). The cuffed end was used for the central PA reconstruction. A retrospective analysis of clinical results, PAs development, and shunt-related complications, interventions, and technique of Glenn operation was performed. The study endpoint was Glenn operation with shunt removal or interstage death.

RESULTS

The hospital and late interstage mortality was 3.8% (n = 2 of 52) and 4% (n = 2 of 50), respectively, and was not shunt-related. During mean follow of 3.7 ± 2.5 years, 48 (92.3%) children underwent Glenn operation at a median age of 6 (range, 2.6-9.1) months. Angiography before the second stage revealed satisfactory branch PAs development (maximum and minimum McGoon ratio of 1.95 ± 0.36 and 1.38 ± 0.38, respectively). The mean maximal diameter of the left PA was smaller than that of the right PA (7.13 ± 2.1 mm vs 8.42 ± 2.2 mm; P = .017), without differences in mean minimal diameter. Two infants required stent implantation in proximal shunt end and 1 required urgent Glenn operation because distal shunt thrombosis. During Glenn operation, 11 (22.9%) children required patch reconstruction of central PAs.

CONCLUSIONS

The cobra-head cuffed graft allowed easy and reproducible reconstruction of the central PA during the Norwood procedure. Using this technique, the development of PAs is satisfactory, the rate of shunt-related complications and interventions is low, and the second stage can be performed without patch material.

Hypoplastic left heart syndrome: current modalities of treatment and outcomes

Hypoplastic left heart syndrome is a constellation of malformations which result from the severe underdevelopment of any left-sided cardiac structures. Once considered to be universally fatal, the prognosis for this condition has tremendously improved over the past four decades since the work of William Norwood in the early 1980s. Today, a staged surgical approach is applied for palliating this distinctive cohort of patients, in which they undergo three operative procedures in the first 10 years of their life. Advancements in medical technologies, surgical techniques, and our growing experience in the management of HLHS have made survival into adulthood a possibility. Through this review, we present the different phases of the staged approach with primary focus on stage 1-its modifications, current technique, alternatives, and latest outcomes.

Hypoplastic left heart syndrome [HLHS]: treatment options in present era

Hypoplastic left heart syndrome (HLHS) is the most severe form of congenital heart defect (CHD). The first successful intervention for it was undertaken by Norwood in 1983. Since then, there have been much development in the pre, intra, and postoperative treatment option in staged palliative surgical procedures. Early diagnostic management, prenatal interventions, innovative diagnostic methods, constantly modified surgical techniques, and hybridization contribute to a significant progress in treatment options. This will allow for defining an optimal strategy of improving survival and quality of life in HLHS patients. The development of intervention cardiology makes possible the stepwise treatment of the defect with one operation only. The first and third stage may be done by hybrid or interventional methods, then only the second stage of treatment needs to be done surgically. The world experience and all the available literature says that the 1st-stage procedure could be done now safely either directly or with a bridge to Norwood followed by the stage 2 with a Glen or Hemi-Fontan and followed by a Fontan down the lane surgically.

Norwood Procedure for Palliation of Hypoplastic Left Heart Syndrome: Right Ventricle to Pulmonary Artery Conduit vs Modified Blalock-Taussig Shunt

Patients with hypoplastic left heart syndrome undergo a series of operations to separate the pulmonary and systemic circulations. The first of at least 3 operations occurs in the newborn period, with a stage I palliation. The goal of stage I palliation is to provide pulmonary blood flow and create an unobstructed systemic outflow tract. Advances in surgical techniques and intraoperative and postoperative care have helped decrease morbidity and mortality for patients with hypoplastic left heart syndrome who have the stage I Norwood operation, but the patients continue to be at increased risk for hemodynamic collapse and adverse outcomes. This article discusses risk factors, surgical approach, postoperative nursing and medical management strategies, differences between and outcomes for the Norwood operation with the right ventricle to pulmonary artery conduit and the Norwood operation with a modified Blalock-Taussig shunt.

Interstage evaluation of homograft-valved right ventricle to pulmonary artery conduits for palliation of hypoplastic left heart syndrome

OBJECTIVE

Palliation of hypoplastic left heart syndrome with a standard nonvalved right ventricle to pulmonary artery conduit results in an inefficient circulation in part due to diastolic regurgitation. A composite right ventricle pulmonary artery conduit with a homograft valve has a hypothetical advantage of reducing regurgitation, but may differ in the propensity for stenosis because of valve remodeling.

METHODS

This retrospective cohort study included 130 patients with hypoplastic left heart syndrome who underwent a modified stage 1 procedure with a right ventricle to pulmonary artery conduit from 2002 to 2015. A composite valved conduit (cryopreserved homograft valve anastomosed to a polytetrafluoroethylene tube) was placed in 100 patients (47 aortic, 32 pulmonary, 13 femoral/saphenous vein, 8 unknown), and a nonvalved conduit was used in 30 patients. Echocardiographic functional parameters were evaluated before and after stage 1 palliation and before the bidirectional Glenn procedure, and interstage interventions were assessed.

RESULTS

On competing risk analysis, survival over time was better in the valved conduit group (P = .040), but this difference was no longer significant after adjustment for surgical era. There was no significant difference between groups in the cumulative incidence of bidirectional Glenn completion (P = .15). Patients with a valved conduit underwent more interventions for conduit obstruction in the interstage period, but this difference did not reach significance (P = .16). There were no differences between groups in echocardiographic parameters of right ventricle function at baseline or pre-Glenn.

CONCLUSIONS

In this cohort of patients with hypoplastic left heart syndrome, inclusion of a valved right ventricle to pulmonary artery conduit was not associated with any difference in survival on adjusted analysis and did not confer an identifiable benefit on right ventricle function.

Association of Shunt Type With Arrhythmias After Norwood Procedure

BACKGROUND

Transplant-free survival for single right ventricle (RV) lesions remains less than 70% at 3 years. Arrhythmia burden, influence of shunt type at Norwood procedure (RV-to-pulmonary artery shunt [RVPAS] versus Blalock-Taussig shunt [BTS]), and implications for mortality risk are not well defined.

METHODS

The authors performed a single-center retrospective analysis of patients with single RV lesions enrolled in a prospective study of arrhythmias after congenital heart surgery.

RESULTS

Fifty-eight patients received a RVPAS and 62 received a BTS, with a median follow-up of 773 days. Overall arrhythmia incidence was 78%, two-thirds of which prompted intervention. Among all types of arrhythmias, only ventricular arrhythmias (VAs) differed by shunt type, which were more common in patients receiving an RVPAS (29% RVPAS versus 14% BTS; p = 0.049). The majority of VAs were transient (69% less than 1 minute), and typically occurred early post-Norwood procedure (median 12 days). No additional variables were associated with development of VAs. Shunt type did not influence transplant-free survival. Within the entire cohort, there was a trend toward increased mortality with prior history of VA (odds ratio, 2.90; 95% confidence interval, 0.99 to 8.90; p = 0.052). For interstage survivors to Glenn palliation, any VA associated with a 14-fold increased risk of death or transplant (hazard ratio, 14.00; 95% confidence interval, 3.66 to 53.40; p < .001). No other tachyarrhythmia or bradyarrhythmia was associated with mortality.

CONCLUSIONS

In this cohort with single RV lesions and prospective rhythm surveillance, patients receiving an RVPAS at Norwood surgery had an increased incidence of VAs compared with patients with a BTS. VAs correlated with late mortality in patients who survived the interstage period.

Open-square technique using a novel pre-cuffed, spiral-ringed conduit for the Norwood procedure

To avoid stenotic conduit events, 2 modifications were added to Norwood reconstruction with a right ventricle-to-pulmonary artery conduit: open-square insertion of a proximal conduit end and use of a pre-cuffed, spiral-ringed conduit. Three consecutive patients treated with this technique successfully underwent bidirectional Glenn with no stenotic events. These modifications are beneficial and safe.

Current Therapy for Hypoplastic Left Heart Syndrome and Related Single Ventricle Lesions

Universally fatal only 4 decades ago, the progress in the 3-stage palliation of hypoplastic left heart syndrome and related single right ventricular lesions has drastically improved the outlook for these patients. Although the stage II operation (hemi-Fontan or bidirectional Glenn) and stage III Fontan procedure have evolved into relatively low-risk operations, the stage I Norwood procedure remains one of the highest-risk and costliest common operations performed in congenital heart surgery. Yet, despite this fact, experienced centers now report hospital survivals of >90% for the Norwood procedure. This traditional 3-stage surgical palliation has seen several innovations in the past decade aimed at improving outcomes, particularly for the Norwood procedure. One significant change is a renewed interest in the right ventricle-to-pulmonary artery shunt as the source of pulmonary blood flow, rather than the modified Blalock-Taussig shunt for the Norwood. The multi-institutional Single Ventricle Reconstruction trial randomly assigned 555 patients to one or the other shunt, and these subjects continue to be followed closely as they now approach 10 years postrandomization. In addition to modifications to the Norwood procedure, the hybrid procedure, a combined catheter-based and surgical approach, avoids the Norwood procedure in the newborn period entirely. The initial hybrid procedure is then followed by a comprehensive stage II, which combines components of both the Norwood and the traditional stage II, and later completion of the Fontan. Proponents of this approach hope to improve not only short-term survival, but also potentially longer-term outcomes, such as neurodevelopment, as well. Regardless of the approach, traditional surgical staged palliation or the hybrid procedure, survivals have vastly improved, and large numbers of these patients are surviving not only through their Fontan in early childhood, but also into adolescence and young adulthood. As this population grows, it becomes increasingly important to understand the longer-term outcomes of these Fontan patients, not only in terms of survival, but also in terms of the burden of disease, neurodevelopmental outcomes, psychosocial development, and quality of life.

Femoral Vein Homograft as Right Ventricle to Pulmonary Artery Conduit in Stage 1 Norwood Operation

BACKGROUND

The polytetrafluoroethylene tube used as right ventricle to pulmonary artery conduit in the stage 1 Norwood operation is associated with risks of suboptimal branch pulmonary artery growth, thrombosis, free insufficiency, and long-term right ventricular dysfunction. Our experience with use of valved femoral vein homograft as right ventricle to pulmonary artery conduit is described.

METHODS

Between June 2012 and December 2015, 15 neonates with hypoplastic left heart syndrome or complex single ventricle underwent stage 1 Norwood operation with valved segment of femoral vein homograft as right ventricle to pulmonary artery conduit. The median age at surgery was 3 days and the mean weight was 3 kg. The size of the femoral vein homograft was 5 mm in 8 patients and 6 mm in 7 patients.

RESULTS

There was no hospital or interstage mortality. Fourteen patients underwent Glenn operation, and 6 have undergone Fontan operation to date. The median Nakata index at pre-Glenn catheterization was 262 mm²/m² (interquartile range: 121 to 422 mm²/m²). No patient had thrombosis of conduit. Most femoral vein conduits remained competent in the first month after stage 1 Norwood operation, although most became incompetent by 3 months. Catheter intervention on the conduit was necessary in 7 patients. Right ventricular function was preserved in most patients at follow-up.

CONCLUSIONS

The use of femoral vein homograft as right ventricle to pulmonary artery conduit in the Norwood operation is safe and associated with good pulmonary artery growth and preserved ventricular function. Balloon dilation of the conduit may be necessary during the interstage period.

Mathematical Analysis and Physical Profile of Blalock-Taussig Shunt and Sano Modification Procedure in Hypoplastic Left Heart Syndrome: Review of the Literature and Implications for the Anesthesiologist

The first stage of surgical treatment for hypoplastic left heart syndrome (HLHS) includes the creation of artificial systemic-to-pulmonary connections to provide pulmonary blood flow. The modified Blalock-Taussig (mBT) shunt has been the technique of choice for this procedure; however, a right ventricle-pulmonary artery (RV-PA) shunt has been introduced into clinical practice with encouraging but still conflicting outcomes when compared with the mBT shunt. The aim of this study is to explore mathematical modeling as a tool for describing physical profiles that could assist the surgical team in predicting complications related to stenosis and malfunction of grafts in an attempt to find correlations with clinical outcomes from clinical studies that compared both surgical techniques and to assist the anesthesiologist in making decisions to manage patients with this complex cardiac anatomy. Mathematical modeling to display the physical characteristics of the chosen surgical shunt is a valuable tool to predict flow patterns, shear stress, and rate distribution as well as energetic performance at the graft level and relative to ventricular efficiency. Such predictions will enable the surgical team to refine the technique so that hemodynamic complications be anticipated and prevented, and are also important for perioperative management by the anesthesia team.

Distal Dunk for Right Ventricle to Pulmonary Artery Shunt in Stage 1 Palliation

The use of a right ventricle-to-pulmonary artery (RV-PA) conduit for stage 1 palliation of hypoplastic left heart syndrome is common. A prospective randomized multiinstitutional study revealed that approximately 40% of those receiving this shunt required intervention on the shunt or pulmonary arteries, or both. A technique has been developed to help ameliorate proximal conduit stenosis. We present a new technique to improve distal conduit stenosis and decrease anastomotic bleeding from this site. The technique involves dunking a segment of the shunt into the pulmonary arteries and suture placement in the shunt rings and not in the polytetrafluoroethylene (PTFE).

Shunt choice in single right ventricle patients: an update

Hypoplastic left heart syndrome, the most common complex congenital heart malformation, is characterized by underdeveloped left-sided heart structures. The Norwood procedure followed by two-staged operations has permitted the extended survival of many of these patients. Survival, however, remains suboptimal with most of the morbidity and mortality occurring during the Norwood procedure hospitalization. The modified Blalock-Taussig shunt has been implicated in contributing to the mortality risk due to decreased systemic diastolic blood pressure and coronary perfusion. Therefore, the right ventricle-to-pulmonary artery shunt was recently reevaluated as a lower-risk source of pulmonary blood flow in the Norwood procedure. The Pediatric Heart Network Single Ventricle Reconstruction trial, sponsored by the NIH National Heart, Lung and Blood Institute, evaluated the two types of shunts during the Norwood procedure. This randomized clinical trial has yielded important insight into the effects of shunt selection on morbidity, mortality, hemodynamics and overall current outcomes for hypoplastic left heart syndrome.

Establishment of right ventricle-pulmonary artery continuity as the first-stage palliation in older infants with pulmonary atresia with ventricular septal defect may be preferable to use of an arterial shunt

OBJECTIVES

Right ventricle-pulmonary artery (RV-PA) conduit and systemic-to-pulmonary artery (S-PA) shunt in younger infants for the first-stage palliation with pulmonary atresia with ventricular septal defect (PAVSD) obtained good results. However, the pulmonary arteries (PA) grow slow in older infants undergoing an S-PA shunt. We compared the clinical outcomes of the two procedures in older infants with PAVSD.

METHODS

A total of 48 patients with PAVSD underwent the first-stage palliative procedure between January 2010 and July 2012. Patients were divided into the RV-PA group and the S-PA group based on whether they had an RV-PA conduit (n = 24) or an S-PA shunt (n = 24). The early and late outcomes were compared between groups.

RESULTS

There was no significant difference in in-hospital mortality, mechanical ventilation time, paediatric intensive care unit stay and hospital stay between groups (all P > 0.05). The RV-PA conduits were associated with better PA growth compared with the S-PA shunts (P < 0.001). The RV-PA group had a higher rate of second-stage biventricular surgery compared with the S-PA group (P = 0.03). The early outcomes among different conduits of the RV-PA conduit were not different (all P > 0.05). A positive correlation was found between the size of conduits and body weight (R(2) = 0.684, P < 0.001).

CONCLUSIONS

In older infants with PAVSD who underwent the first-stage palliative procedure, early outcomes showed no difference between the RV-PA conduit group and the S-PA shunt group. The RV-PA conduits were associated with better growth of the PA and higher rates of second-stage biventricular repair. Autologous pericardium is a good choice for RV-PA conduits, and there is a correlation between body weight and size of conduit.

Current status of the hybrid approach for the treatment of hypoplastic left heart syndrome

The hybrid approach for hypoplastic left heart syndrome (HLHS), consisting of bilateral pulmonary artery banding and ductal stenting, has emerged as an alternative to the traditional Norwood approach. This approach defers open heart surgery to beyond the neonatal period, which is believed to reduce postoperative mortality and morbidity and improve neurological development as compared with the conventional approach. However, there have been no scientific studies supporting these hypotheses. Recently, there seems to be a tendency that many centers recommend the hybrid approach as an interim procedure to rescue preoperative high-risk patients. Currently, the decision to adopt the hybrid approach or the Norwood approach seemed to be based on the preference of congenital heart surgeons and cardiologists. Further investigation including a randomized multi-center study would allow a scientific decision as to which approach is more appropriate for the patient with HLHS.

Impact of shunt type on growth of pulmonary arteries after norwood stage I procedure: current best available evidence

The past decade has seen a substantial improvement in the outcome following surgical palliation for hypoplastic left heart syndrome. This has been attributed to modifications in the surgical as well as postoperative management strategies. One such modification is the reemergence of the right ventricle to pulmonary artery (RV-PA) shunt as an alternative to the modified Blalock-Taussig (mBT) shunt as the source of pulmonary blood flow. The RV-PA shunt has been shown to improve the immediate surgical outcome compared with the classic Norwood procedure with an mBT shunt. Despite the several reported advantages, the impact of the RV-PA shunt on growth of the pulmonary arteries and incidence of late development of central PA stenosis remains unclear. This systematic review evaluates the current best available evidence to address this issue and concludes that the evidence from retrospective studies and only available randomized controlled trial (RCT) is conflicting. The retrospective studies predominantly suggest that the Norwood procedure with RV-PA shunt may have favorable effects on the development of the pulmonary arteries due to even distribution of pulmonary blood flow with greater distal left pulmonary artery growth, resulting in more balanced distal branch pulmonary artery size albeit with a greater degree of central pulmonary artery hypoplasia needing surgical attention. On the contrary, the RCT reports that the overall size of the pulmonary artery on angiography before the stage II procedure was smaller in the RV-PA shunt group than in the mBT shunt group, with no information available on incidence of central pulmonary hypoplasia.

Left ventricle after palliation of hypoplastic left heart syndrome: friend, fiend, or innocent bystander?

Hypoplasia of the left side of the heart is the most common cause of death from congenital heart disease in the first weeks of life. Once considered a surgically fatal disease, hypoplasia has been successfully palliated for more than 30 years. Although the palliative route is staged by an early differential bypass of the systemic outflow and the venous inflow to the right ventricle, the left ventricle remains anatomically and biologically influential throughout. Given the variation of the left ventricle, contemporary outcomes for different hypoplastic left heart subsets can vary both early after palliation and long term. This review critically examines the contemporary understanding of the structure and function of the hypoplastic ventricle in this syndrome. It also provides insight into future research directions relevant to clinicians and surgeons.

Individualized approach in the management of patients with hypoplastic left heart syndrome (HLHS)

Over the past decade new variations on the "classic" first stage palliation (the Norwood/BT shunt) for patients with Hypoplastic Left Heart Syndrome have emerged and been vetted by the medical community. A "one size fits all" approach may not be adequate anymore. In this review, the optimal indications for the various palliative options (Norwood/BT shunt, Norwood/RV-PA conduit, Hybrid Stage I with or without ductal stenting, heart transplantation) are reviewed from a standpoint of the initial anatomy and physiology of the patient, letting it guide clinical management. Current knowledge useful for decision-making is also reviewed as objectively as possible.

An angiographic predictor of pulmonary artery stenosis after the Norwood-Sano operation for hypoplastic left heart syndrome

The objective of this study was to determine angiographic predictors of future pulmonary artery stenosis (PS) in patients with hypoplastic left heart syndrome (HLHS) at the time of pre-stage 2 cardiac catheterization (PS2C). The Sano modification of the Norwood operation (NSO) for HLHS includes placement of a right ventricle-to-pulmonary artery (RV-PA) conduit. Branch PS is a recognized complication. Data from patients with HLHS who underwent NSO from 2005 to 2009 and who underwent PS2C were reviewed retrospectively. Nakata and McGoon indices were calculated in the traditional fashion, and modified Nakata and McGoon indices were calculated using the narrowest branch PA diameters. Thirty-three patients underwent NSO and 28 patients underwent PS2C. Mean follow-up was 35.8 ± 7.5 months. Ten (36 %) patients had significant left branch PS, with two requiring balloon angioplasty and eight requiring stent placement, a median of 15.2 months after PS2C (interquartile range 1.2, 32.8). The modified Nakata index was predictive of future intervention for left PS (receiver operating characteristic curve area under the curve 0.811), with a cut-off of 135 mm(2)/m(2) and a sensitivity of 100 % and specificity of 72.2 %. A modified Nakata index <135 mm(2)/m(2) at PS2C predicts future need for intervention on left-branch PS in patients with HLHS after the NSO. Surgical pulmonary arterioplasty at the time of stage 2 surgical palliation may obviate the need for future interventions.

Hypoplastic left heart syndrome: current considerations and expectations

In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients.

Second-Stage Palliation After Bilateral Pulmonary Artery Bands for HLHS and its Variants—Which is Better, Modified Norwood or Norwood Plus Bidirectional Glenn?

Background. The purpose of this study was to evaluate the surgical outcomes and pulmonary artery (PA) development associated with a new strategy wherein the modified Norwood (N) procedure is performed at 1-2 months after bilateral pulmonary artery banding (PAB). Methods. Between January 2008 and February 2010, 16 patients underwent Norwood-type operation after previous bilateral PAB. For analysis, patients were divided into two groups. Group I (n = 11) underwent modified Norwood procedure with either right modified Blalock Taussig (RMBT) shunt (n = 4) or right ventricle to pulmonary artery (RV-PA) conduit (n = 7). Group II (n = 5) underwent Norwood procedure plus bidirectional Glenn anastomosis. Diagnoses were hypoplastic left heart syndrome in 6 and its variants in 10. Results. There was no surgical death and no late death. Pulmonary artery interventions were performed at the time of the Norwood procedure in 27% in Group I and in 100% in Group II (p < 0.05). Additional PA interventions were performed during the period of follow-up in 4 cases in Group I (36.4%), and in 4 cases in Group II (80.0%). Additional Blalock Taussig shunts were performed in 7 patients, resulting in significant increase in PA index. In all, four patients have reached total cavopulmonary connection, and one has undergone biventricular repair. Eight patients in Group I and one patient in II Group reached bidirectional Glenn anastomosis. In Gp II, two patients showed LPA narrowing or obstruction with PA index of 80 ± 12 mm2/m2. Conclusions. Regarding the second-stage palliation after bilateral PAB, modified Norwood procedure with either RMBT or RV-PA conduit has some advantages compared with Norwood plus BDG with respect to subsequent pulmonary artery development. Additional BT shunt may contribute to PA development, even in the patients with Norwood procedure with RV-PA conduit.

Can Randomized Clinical Trials Impact the Surgical Approach for Hypoplastic Left Heart Syndrome?

The Eighth International Conference of the Pediatric Cardiac Intensive Care Society was held in Miami, Florida, December 8 to 11, 2010. The program included a session dedicated to the management of hypoplastic left heart syndrome (HLHS), with particular emphasis on the innovations that have led to contemporary schemes of management and the role of clinical trials in the evolution and acceptance of these strategies. An invited panel of experts reviewed the historical evolution of staged surgical reconstruction, the randomized clinical trials that have been undertaken thus far, and the extent to which these have, or have not, influenced individual and institutional approaches to management of HLHS.

Modified Norwood procedure with a handmade down-sizing valved right ventricle-to-pulmonary artery conduit

First-stage palliation of hypoplastic left heart syndrome has been revolutionized by the recent introduction of a right ventricle-to-pulmonary artery (RV-PA) conduit as an alternative to a systemic-to-pulmonary shunt. However, most conduits are unvalved, and the use of valved xenografts was abandoned during the early era of this operation. We performed a successful modified Norwood operation in a 2-month-old infant with aortic atresia and ventricular and atrial septal defects using a hand-made down-sizing valved graft as an RV-PA conduit. The postoperative course was uneventful with well-balanced pulmonary and arterial perfusion. We believe that minimization of the regurgitant volume from an unvalved prosthetic conduit by utilizing this modification might be of benefit in this particular group of patients.

Rudimentary right ventricle to pulmonary artery shunt in the Norwood procedure

We describe here successful palliative repair of tricuspid atresia, hypoplastic right ventricle, transposition of the great arteries, and hypoplastic aortic arch in a neonate. The repair consisted of the Norwood procedure with a rudimentary right ventricle to pulmonary artery shunt, which was located on the right side of a neo-aorta. This procedure could be a useful adjunct to avoid left ventriculotomy and its subsequent dysfunction.

Right Ventricle-to-Pulmonary Artery Shunt in Norwood Procedure: Early Results

The aim of this study was to evaluate experience and predictors of early mortality in patients with hypoplastic left heart syndrome (HLHS)–type defects undergoing Norwood procedure (NP) with right ventricle-to-pulmonary artery (RV-PA) shunt. Between 2001 and 2009, a consecutive series of 229 children with HLHS-type single ventricle underwent NP with application of RV-PA shunt. Demographic, echocardiographic, and clinical perioperative data were retrospectively analyzed. The mean duration of follow-up of survivors was 4.5 ± 2.1 years (60 days to 8.1 years). Follow-up was complete for 92.1% of patients. Major early postoperative complications included sepsis/generalized infection in 40 (17.5%), pericardial effusion in 9 (3.9%), and wound infection in 8 (3.5%). The early (30-day) survival was 87.8% (n = 201). In the late postoperative period, 12 (5.9%) died. Early nonsurvivors were more frequently older than 14 days ( P = .045) at initial surgery, had lower operative weight ( P = .024), had more frequent associated cardiac ( P < .001) and/or extracardiac anomalies ( P < .001), and were more likely to have a restrictive interatrial communication before operation ( P = .024). Use of the right RV-PA shunt has helped to mitigate some previously described predictors of early death after NP. Longer follow-up will be required to determine whether the RV-PA shunt modification confers an important survival benefit.

Staged surgical palliation in hypoplastic left heart syndrome and its variants

BACKGROUND

Surgical options for infants with hypoplastic left heart syndrome (HLHS) and/or its variants are cardiac transplantation or the heart-preserving staged palliation with Norwood operation,followed by a two-staged Fontan procedure. We describe our 17-year experience with staged palliation of HLHS and/or its variants.

METHODS

Between December 1989 and December 2006, 64 patients with HLHS and/or its variants underwent a Norwood procedure (mean age/weight, 11.8+/-2.5 days/3.4 kg). Forty-four patients had classical HLHS. Twenty-eight percent had associated congenital cardiac, structural, and genetic anomalies. Subsequently, 25 patients underwent a bidirectional Glenn procedure (stage II) and 11 patients a modified Fontan procedure (stage III). Others await stage II and/or stage III. The follow-up was 143.2 patient-years.

RESULTS

Including the learning curve, overall early mortality from 1989 to 1999 after the Norwood procedure was 39.06%. This decreased tremendously for the last seven years, and reduced to 12.8% in 2000 to 2003 until 0% in 2004 to 2006 (p < 0.005). The causes of mortality were sepsis, capillary leak,or heart failure. Three patients died between stages II and III. One patient underwent heart transplantation after the second stage because of heart failure. Among 34 Norwood survivors, four are slightly tachypneic from a mild pulmonary hyperperfusion; one presents symptoms of minimal brain disease.

CONCLUSION

This report identified an outcome improvement after staged palliation of HLHS, attributed to an increase in experience and expertise gained over time. Lower operative weight, ascending aortic size, prolonged duration of cardiopulmonary bypass, and hypothermic circulatory arrest were identified to significantly influence early mortality after the Norwood procedure.

Single ventricle physiology: surgical options, indications and outcomes

PURPOSE OF REVIEW

Among the most frequently encountered congenital heart malformations are those with so-called single ventricle physiology, in which there is only one ventricle to pump blood to the pulmonary and systemic vascular beds, respectively. Long-term survival is possible, based on the principle of right heart bypass, whereby the ventricle pumps blood only to the systemic circuit, whereas pulmonary blood flow occurs passively. Such a circulatory system is achieved in a series of staged reconstructive operations, each of which was formerly accompanied by very high rates of major morbidity and mortality. Current approaches to single ventricle physiology as well as areas of controversy will be reviewed.

RECENT FINDINGS

The development of a number of inventive operations, combined with a greater understanding of the physiologic requirements for success after single ventricle reconstruction has resulted in dramatic improvements in outcomes. The identification and modification of risk factors as well as the recent development of catheter-based intervention offer the real prospect of significant continued improvement.

SUMMARY

Advances in the care of children with single ventricle hearts have resulted in remarkably improved prognosis, with the expectation of continued improvement in not only survival but also quality of life.

Two-Year Survival and Mental and Psychomotor Outcomes After the Norwood Procedure

Background— The Norwood procedure for stage 1 palliation of hypoplastic left heart syndrome is performed with either the modified Blalock-Taussig (MBTS) or the right ventricle–to–pulmonary artery (RVPA) shunt. In our institution, surgical practice changed from use of the MBTS to use of the RVPA shunt in 2002. We analyzed survival and mental and psychomotor outcomes of the 2 consecutive surgical eras.

Methods and Results— Between September 1996 and July 2005, 94 neonates with hypoplastic left heart syndrome underwent the Norwood procedure. Patients were recruited as neonates and followed up prospectively. Health, mental, and psychomotor outcomes (Bayley Scales of Infant Development-II) were assessed at 2 years. The study subjects were from the Norwood-MBTS era (n=62; 1996 to 2002) or the Norwood-RVPA era (n=32; 2002 to 2005). In the MBTS era, early and 2-year mortality rates were 23% (14/62) and 52% (32/62); the mean (SD) mental and psychomotor developmental indices were 79 (18) and 67 (19). In the RVPA era, early and 2-year mortality rates were 6% (2/32) and 19% (6/32); the mean (SD) mental and psychomotor developmental indices were 85 (18) and 78 (18). The 2-year mortality rate ( P =0.002) and the psychomotor developmental index ( P =0.029) were improved in the more recent surgical era. On multivariable Cox regression analysis, postoperative highest serum lactate independently predicted 2-year mortality in the MBTS and RVPA eras.

Conclusions— Analysis of 2 consecutive surgical eras of hypoplastic left heart syndrome patients undergoing the Norwood procedure showed a significant improvement in 2-year survival and psychomotor development in the more recent era. Adverse neurodevelopmental outcome in this patient population remains a concern.

Pathological changes and myocardial remodelling related to the mode of shunting following surgical palliation for hypoplastic left heart syndrome

BACKGROUND

The modification of placing the shunt from the right ventricle to the pulmonary arteries, also known as Sano procedure, has allegedly improved results over the short term in surgical palliation of hypoplastic left heart syndrome with the Norwood procedure. With this in mind, we reviewed autopsied specimens from neonates and children who did not survive after either a classic arterio-pulmonary shunt, or the modified procedure with the shunt placed from the right ventricle to the pulmonary arteries, so as to evaluate the pathological substrates of the remodelling of the systemic right ventricle, assessing any differences induced by the 2 techniques.

METHODS

We obtained the hearts from 11 patients with neonatal diagnosis of hypoplastic left heart syndrome who died after the first or second stages of the Norwood sequence of operations, comparing them with 6 normal hearts matched for age and weight. Macroscopic, microscopic and morphometric analysis were performed on each specimen, evaluating the diameter of the myocytes, extracellular matrix remodelling in terms of fibrosis and type of collagen, and vascularization in terms of capillary density.

RESULTS

Hypertrophy of the myocytes was significantly increased in the hearts from patients having either a classic arterio-pulmonary or the ventriculo-pulmonary modification of the shunt compared to controls (p < 0.05). Myocardial fibrosis was increased in those having a shunt placed from the right ventricle to the pulmonary arteries when compared to the other 2 groups. The ratio of collagen I to collagen III was similar in those undergoing a classic arterio-pulmonary shunt compared to controls (0.94), but was lower in those having a shunt placed from the right ventricle to the pulmonary arteries (0.61), with an increase in collagen type III. The density of capillaries was lower in those who had undergone a classic arterial shunt when compared to the others.

CONCLUSION

We have shown greater remodelling of the ventricular myocardial extracellular matrix in patients having a shunt from the right ventricle to the pulmonary arteries when compared to those having a classic arterio-pulmonary shunt, with this remodelling progressing even after the neonatal period. This may influence a later suboptimal ventricular performance.

Does a ventriculotomy have deleterious effects following palliation in the Norwood procedure using a shunt placed from the right ventricle to the pulmonary arteries?

INTRODUCTION

A recent modification to the Norwood procedure involving a shunt placed directly from the right ventricle to the pulmonary arteries may improve postoperative haemodynamics. Concerns remain, however, about the potential problems produced by the required ventriculotomy.

METHODS

We compared 76 patients with hypoplastic left heart syndrome who underwent the Norwood procedure, 35 receiving a modified Blalock-Taussig shunt and the remaining 41 a shunt placed directly from the right ventricle to the pulmonary arteries. We reviewed their subsequent progress through the second stage of palliation. A single observer graded right ventricular function, and the severity of tricuspid regurgitation, based on blinded review of the most recent echocardiograms prior to the second stage of palliation.

RESULTS

At the time of catheterization prior to the second stage, patients with a shunt placed from the right ventricle to the pulmonary arteries, rather than a modified Blalock-Taussig shunt, had higher arterial diastolic blood pressure, at 44 versus 40 millimetres of mercury, p equal to 0.02, lower ventricular end diastolic pressures, at 8 versus 11 millimetres of mercury, p equal to 0.0002, and larger pulmonary arteries as judged using the Nakata index, at 270 versus 188 millimetres squared per metres squared, p equal to 0.009. There was no difference in qualitative ventricular systolic function or tricuspid regurgitation between groups. No differences were found between groups during the hospitalization following the second stage of palliation. A trend towards improved survival to the second stage was seen following the construction of a shunt from the right ventricle to the pulmonary arteries.

CONCLUSIONS

Construction of a shunt from the right ventricle to the pulmonary arteries is associated with lower right ventricular end diastolic pressures, larger pulmonary arterial size, and higher systemic arterial diastolic pressures. No apparent deleterious effects of the right ventriculotomy were observed in terms of qualitative ventricular systolic function or tricuspid regurgitation.

Stage I palliation for hypoplastic left heart syndrome: Norwood versus Sano modification

PURPOSE OF REVIEW

Advancements in surgical technique and perioperative care have significantly improved the survival of infants born with hypoplastic left heart syndrome. A recent modification to the Norwood procedure is being adopted by many centers to improve postoperative hemodynamic stability and survival to stage II palliation. The late effects of this modification, however, are speculated and have not been investigated.

RECENT FINDINGS

Center-specific improved short-term outcomes have been reported in a few small, nonrandomized studies of a new approach to the Norwood procedure, which utilizes a right ventricle to pulmonary artery shunt or Sano modification to provide pulmonary blood flow rather than the standard modified Blalock-Taussig shunt.

SUMMARY

The classic Norwood procedure and Sano modification each have specific advantages and disadvantages in both the short and long term. Data comparing the two techniques are nonrandomized, contradictory, and utilize historical controls. The optimal shunt to improve survival to the second-stage palliation is unknown. A multicenter randomized clinical trial comparing the Sano with the modified Blalock-Taussig shunt in hypoplastic left heart syndrome or variants is currently in progress and should hopefully provide future guidelines for shunt selection based on clinical presentation.

State of the art of cardiac surgery in patients with congenital heart disease

During the last 20 years, pediatric cardiac surgery has been characterized by important changes, with reductions in surgical mortality and the achievement of complete repair at an earlier age, thus avoiding multiple procedures and strongly ameliorating the global outcome of these patients. In this review, we describe the actual trends in the surgical treatment of cardiac malformations. We analyze two groups of patients: in the first group (septal defects, tetralogy of Fallot, transposition of the great arteries, aortic stenosis and coarctation) the indications are well established and the goal is represented by a lessening of the surgical trauma and post-operative morbidity, with stable results in the follow-up. In the second group (univentricular heart, pulmonary atresia and intact ventricular septum, double discordance, conduit, hypoplastic left heart syndrome), the lesions are still considered complex and submitted to ongoing experimental and clinical research, in order to improve the post-surgical history of these diseases.

New developments in the treatment of hypoplastic left heart syndrome

In the current decade, the prognosis of newborns with hypoplastic left heart syndrome, previously considered a uniformly fatal condition, has dramatically improved through refinement of rapidly evolving treatment strategies. These strategies include various modifications of staged surgical reconstruction, orthotopic heart transplantation, and hybrid palliation using ductal stenting and bilateral pulmonary artery banding. The variety of treatment approaches are based on different surgical philosophies, and each approach has its unique advantages and disadvantages. Nonetheless, multiple experienced centers have reported improved outcomes in each one of those modalities. The purpose of this review is to outline recent developments in the array of currently available management strategies for neonates with hypoplastic left heart syndrome. Because the vast majority of deaths in this patient population occur within the first months of life, the focus of the review will be evaluation of the impact of these management strategies on survival in the neonatal and infant periods.

Right Ventricle–to–Pulmonary Artery Conduit Versus Blalock-Taussig Shunt: A Hemodynamic Comparison

BACKGROUND

A comprehensive assessment of 48 hour postoperative hemodynamics in neonates randomized to the right ventricle-to-pulmonary artery (RV-PA) conduit or modified Blalock-Taussig (BT) shunt for stage 1 palliation of hypoplastic left heart syndrome was performed to determine the potential benefits of the modified technique.

METHODS

Randomization to either RV-PA conduit or BT shunt was stratified by surgeon and the presence of aortic atresia. The designated procedure was performed by using hypothermic cardiopulmonary bypass with phenoxybenzamine, continuous cerebral perfusion, pH-stat blood gas management, and continuous postoperative venous oximetry. Differences between treatments were analyzed by time-series generalized least-squares regression, chi2 tests, two-way repeated measures analysis of variance, and the Levene variance ratio test for variability in parameters, as appropriate.

RESULTS

All patients underwent the procedure to which they were randomized. There were no differences in age, weight, deep hypothermic circulatory arrest, or cardiopulmonary bypass times between patients receiving the BT shunt (n = 8) or the RV-PA conduit (n = 9). There was one early and one late death in the RV-PA conduit group, and one interstage death in the BT shunt group. Other than diastolic blood pressure (39 mm Hg in BT shunt versus 46 mm Hg in RV-PA conduit, p < 0.001), there were no differences in the mean values of arterial saturation, venous oximetry, mean arterial blood pressure, pulmonary-to-systemic flow ratio (Qp/Qs), or any other physiologic or inotropic support variable between groups. The variability of physiologic values related to pulmonary blood flow was greater in the RV-PA group (Qp/Qs coefficient of variation, 0.91 versus 2.50, p < 0.001).

CONCLUSIONS

In this randomized prospective study, no hemodynamic benefits of the RV-PA modification for stage 1 palliation of hypoplastic left heart syndrome were found. Pulmonary blood flow was more variable, and the diastolic blood pressure was higher. These findings did not influence indicators of systemic oxygen delivery with our afterload reduction strategy.

Homograft valved right ventricle to pulmonary artery conduit as a modification of the Norwood procedure

BACKGROUND

The use of a right ventricle to pulmonary artery (RV-PA) conduit in the Norwood procedure has been proposed to increase postoperative hemodynamic stability. A valve within the conduit should further decrease RV volume load. We report our clinical experience with this modification.

METHODS AND RESULTS

From February 2002 through August 2005, we performed 88 consecutive Norwood procedures using RV-PA conduits. We used composite valved conduits made from cryopreserved homograft and polytetrafluoroethylene (PTFE) in 66 cases (54 pulmonary, 12 aortic homografts), other valved conduits in 14, and unvalved PTFE in 8 cases. Hospital survival was 88.6% overall and increased to 93.1% after the initial year. Early interventions were required in 18 patients (16 for cyanosis). Prestage II cardiac catheterization was performed at a mean age of 126 days. Mean Qp/Qs was 1, with mean aortic saturation 71%, mean O2 extraction 24%, and mean right ventricular end-diastolic pressure 9 mm Hg. Patient weight, use of an aortic homograft valve in the conduit, stage I palliation within the first year of our experience, and low O2 extraction and high transpulmonary gradient prestage II were risk factors for overall death. Early interventions were more frequent in aortic valve conduits compared with all other conduits.

CONCLUSIONS

The valved RV-PA conduit was associated with low early mortality after the Norwood procedure. The majority of these patients had normal cardiac output and well-maintained RV function. There may be a higher risk for early conduit interventions and death when aortic valve homografts are used in the RV-PA conduit.

The nomenclature, definition and classification of hypoplastic left heart syndrome

The hypoplastic left heart syndrome encompasses a spectrum of cardiac malformations that are characterized by significant underdevelopment of the components of the left heart and the aorta, including the left ventricular cavity and mass. At the severe end of the spectrum is found the combination of aortic and mitral atresia, when the left ventricle can be close to non-existent. At the mild end are the patients with hypoplasia of the aortic and mitral valves, but without intrinsic valvar stenosis or atresia, and milder degrees of left ventricular hypoplasia. Although the majority of the patients are suitable only for functionally univentricular repair, a small minority may be candidates for biventricular repair. The nature of the syndrome was a topic for discussion at the second meeting of the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, the Nomenclature Working Group, held in Montreal, Canada, over the period January 17 through 19, 2003. Subsequent to these discussions, the Nomenclature Working Group was able to create a bidirectional crossmap between the nomenclature initially produced jointly on behalf of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and the alternative nomenclature developed on behalf of the Association for European Paediatric Cardiology. This process is a part of the overall efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system of nomenclature for paediatric and congenital cardiac disease, the International Paediatric and Congenital Cardiac Code. In this review, we discuss the evolution of nomenclature and surgical treatment for the spectrum of lesions making up the hypoplastic left heart syndrome and its related malformations. We also present the crossmap of the associated terms for diagnoses and procedures, as recently completed by the Nomenclature Working Group.

Improved Hemodynamics and Outcome After Modified Norwood Operation on the Beating Heart

BACKGROUND

Recently introduced cardiopulmonary bypass techniques to avoid circulatory arrest were proposed to improve organ function of the modified Norwood operation for hypoplastic left heart syndrome. This study compares postoperative hemodynamics and survival in patients who underwent Norwood procedure on the beating heart to those operated on with cardioplegic cardiac arrest.

METHODS

Between October 2002 and January 2005, 26 consecutive patients aged 4 to 275 days (median, 9 days) and weighing 2.9 to 4.4 kg (median, 3.4 kg) underwent Norwood palliation: 13 with continuous coronary and systemic perfusion (group 1), and 13 with only continuous systemic perfusion but arrested heart (group 2). Standard hemodynamic measurements, lactate levels, arterial and superior vena cava oxygen saturations, and inotropic agents required for postoperative hours 0, 6, 12, 18, 24, and 48 were retrospectively analyzed. For univariate comparison of different variables, chi2 test, Fisher's exact test, or Student's t test was used as appropriate.

RESULTS

In group 1 significantly higher mean arterial pressure (53 +/- 0.8 versus 50 +/- 1.2 mm Hg; p = 0.04), higher central oxygen saturation (54% +/- 1.1% versus 50% +/- 1.5%; p = 0.03), higher urinary output (5.3 +/- 0.4 versus 4.4 +/- 0.4 mL.kg(-1).h(-1); p = 0.09), lower lactate levels (2.4 +/- 0.1 versus 4.1 +/- 0.6 mmol/L; p = 0.009) with lower doses of norepinephrine (0.03 +/- 0.004 versus 0.14 +/- 0.03 microg.kg(-1).min(-1); p = 0.002) were recognized. Hospital mortality was 0% in group 1 and 38.5% (5 of 13) in group 2 (p = 0.04). Univariate analysis revealed mortality to be also correlated with preoperative intubation (p = 0.02) and the use of preoperative inotropic agents (p = 0.03).

CONCLUSIONS

Avoidance of cardiac arrest by means of continuous coronary perfusion in addition to continuous systemic perfusion significantly improves postoperative hemodynamic performance and thus helps to reduce hospital mortality after the modified Norwood procedure.