Comparison of shunt types in the Norwood procedure for single-ventricle lesions

Effect of endovascular stenting of right ventricle to pulmonary artery conduit stenosis in infants with hypoplastic left heart syndrome on stage II outcomes

There is growing awareness that the Norwood procedure with the Sano modification is prone to early right ventricular to pulmonary artery (RV-PA) conduit stenosis resulting in systemic oxygen desaturation, increased interstage morbidity, and death. We report our experience with endovascular stent placement for conduit stenosis and compare the outcomes at stage II surgery between stented and nonstented infants. The medical records of all patients with hypoplastic left heart syndrome who received an RV-PA conduit at Norwood palliation from May 2005 to January 2010 were reviewed. The preoperative anatomy, demographics, operative variables, and outcomes pertaining to the Norwood and subsequent stage II surgeries were obtained and compared between stented and nonstented infants. The pre- and post-stent oxygen saturation, stenosis location, type and number of stents implanted, concomitant interventions, procedure-related complications, and reinterventions were collected. Of the 66 infants who underwent the Norwood procedure with RV-PA conduit modification, 16 (24%) received stents. The anatomy, demographics, and outcome variables after the Norwood procedure were similar between the stented and nonstented infants. The age at catheterization was 93 ± 48 days, and the weight was 4.9 ± 1.2 kg. The oxygen saturation increased from 66 ± 9% before intervention to 82 ± 6% immediately after stenting (p <0.0001). No interstage surgical shunt revisions were performed in either group. Age, weight, pre-stage II echocardiographic variables, oxygen saturation, and operative and outcome variables, including mortality, were similar between the 2 groups. In conclusion, endovascular stent placement for RV-PA conduit stenosis after the Norwood procedure leads to improved systemic oxygen levels and prevents early performance of stage II surgery without compromising stage II outcomes.

Risk factors for hospital morbidity and mortality after the Norwood procedure: A report from the Pediatric Heart Network Single Ventricle Reconstruction trial

OBJECTIVES

We sought to identify risk factors for mortality and morbidity during the Norwood hospitalization in newborn infants with hypoplastic left heart syndrome and other single right ventricle anomalies enrolled in the Single Ventricle Reconstruction trial.

METHODS

Potential predictors for outcome included patient- and procedure-related variables and center volume and surgeon volume. Outcome variables occurring during the Norwood procedure and before hospital discharge or stage II procedure included mortality, end-organ complications, length of ventilation, and hospital length of stay. Univariate and multivariable Cox regression analyses were performed with bootstrapping to estimate reliability for mortality.

RESULTS

Analysis included 549 subjects prospectively enrolled from 15 centers; 30-day and hospital mortality were 11.5% (63/549) and 16.0% (88/549), respectively. Independent risk factors for both 30-day and hospital mortality included lower birth weight, genetic abnormality, extracorporeal membrane oxygenation (ECMO) and open sternum on the day of the Norwood procedure. In addition, longer duration of deep hypothermic circulatory arrest was a risk factor for 30-day mortality. Shunt type at the end of the Norwood procedure was not a significant risk factor for 30-day or hospital mortality. Independent risk factors for postoperative renal failure (n = 46), sepsis (n = 93), increased length of ventilation, and hospital length of stay among survivors included genetic abnormality, lower center/surgeon volume, open sternum, and post-Norwood operations.

CONCLUSIONS

Innate patient factors, ECMO, open sternum, and lower center/surgeon volume are important risk factors for postoperative mortality and/or morbidity during the Norwood hospitalization.

Variation in perioperative care across centers for infants undergoing the Norwood procedure

OBJECTIVES

In the Single Ventricle Reconstruction trial, infants undergoing the Norwood procedure were randomly allocated to undergo a right ventricle-to-pulmonary artery shunt or a modified Blalock-Taussig shunt. Apart from shunt type, subjects received the local standard of care. We evaluated variation in perioperative care during the Norwood hospitalization across 14 trial sites.

METHODS

Data on preoperative, operative, and postoperative variables for 546 enrolled subjects who underwent the Norwood procedure were collected prospectively on standardized case report forms, and variation across the centers was described.

RESULTS

Gestational age, birth weight, and proportion with hypoplastic left heart syndrome were similar across sites. In contrast, all recorded variables related to preoperative care varied across centers, including fetal diagnosis (range, 55%-85%), preoperative intubation (range, 29%-91%), and enteral feeding. Perioperative and operative factors were also variable across sites, including median total support time (range, 74-189 minutes) and other perfusion variables, arch reconstruction technique, intraoperative medication use, and use of modified ultrafiltration (range, 48%-100%). Additional variation across centers was seen in variables related to postoperative care, including proportion with an open sternum (range, 35%-100%), median intensive care unit stay (range, 9-44 days), type of feeding at discharge, and enrollment in a home monitoring program (range, 1%-100%; 5 sites did not have a program). Overall, in-hospital death or transplant occurred in 18% (range across sites, 7%-39%).

CONCLUSIONS

Perioperative care during the Norwood hospitalization varies across centers. Further analysis evaluating the underlying causes and relationship of this variation to outcome is needed to inform future studies and quality improvement efforts.

Fontan completion after Norwood with bidirectional Glenn shunt: their haemodynamics and pulmonary artery configuration

OBJECTIVES

We ranked the haemodynamics and pulmonary artery (PA) configurations of Norwood with bidirectional Glenn shunt (NW-G) patients among the other staged Fontan completion (conventional) patients in this study.

METHODS

Between August 2001 and April 2010, 91 consecutive patients completed staged Fontan operations. Among them, NW-G was performed in 11.

RESULTS

There was no operative or late death except in one case which resulted from a reoperation after Fontan completion. Although the age at bidirectional Glenn (BDG) and Fontan completion was younger in NW-G (4.2 vs. 10.9 months, P < 0.01, and 2.3 vs. 3.3 years, P < 0.01), the interval between BDG and Fontan completion was not significantly different in these groups (23.6 vs. 28.0 months, P = 0.71). On Fontan completion, the extracardiac conduit size was significantly different (16.4 vs. 17.7 mm, P < 0.01). However, the pulmonary artery size (PA index) and the PA pressure were not significantly different (165.4 vs. 205.1 mm(2)/m(2), P = 0.23, and 13.4 vs. 11.0 mmHg, P = 0.08). Particularly in hypoplastic left heart syndrome patients, the PA index was not significantly different between these groups (165.4 vs. 174.9 mm(2)/m(2), P = 0.59).

CONCLUSIONS

The NW-G patients could have a subsequent Fontan completion with good results. There was no significant difference with respect to Fontan completion.

Ethical issues in cardiac surgery

While ethical behavior has always been part of cardiac surgical practice, ethical deliberation has only recently become an important component of cardiac surgical practice. Issues such as informed consent, conflict of interest and professional self-regulation, among many others, have increasingly attracted the attention of cardiac surgeons. This article covers several broad topics of interest to cardiac surgeons and cardiologists and discusses several other topics more briefly. There is much uncertainty regarding what the future holds for cardiac surgical practice, research and culture and we also discuss the background of ethical issues to serve as a platform for envisioning what is to come.

Does initial shunt type for the Norwood procedure affect echocardiographic measures of cardiac size and function during infancy?: the Single Vventricle Reconstruction trial

BACKGROUND

The Pediatric Heart Network trial comparing outcomes in 549 infants with single right ventricle undergoing a Norwood procedure randomized to modified Blalock-Taussig shunt or right ventricle-pulmonary artery shunt (RVPAS) found better 1-year transplant-free survival in those who received RVPAS. We sought to compare the impact of shunt type on echocardiographic indices of cardiac size and function up to 14 months of age.

METHODS AND RESULTS

A core laboratory measured indices of cardiac size and function from protocol exams: early after Norwood procedure (age 22.5 ± 13.4 days), before stage II procedure (age 4.8 ± 1.8 months), and at 14 months (age 14.3 ± 1.2 months). Mean right ventricular ejection fraction was <50% at all intervals for both groups and was higher in the RVPAS group after Norwood procedure (49 ± 7% versus 44 ± 8%; P<0.001) but was similar by 14 months. Tricuspid and neoaortic regurgitation, diastolic function, and pulmonary artery and arch dimensions were similar in the 2 groups at all intervals. Neoaortic annulus area (4.2 ± 1.2 versus 4.9 ± 1.2 cm(2)/m(2)), systolic ejection times (214.0 ± 29.4 versus 231.3 ± 28.6 ms), neoaortic flow (6.2 ± 2.4 versus 9.4 ± 3.4 L/min per square meter), and peak arch velocity (1.9 ± 0.7 versus 2.2 ± 0.7 m/s) were lower at both interstage examinations in the RVPAS compared with the modified Blalock-Taussig shunt group (P<0.001 for all), but all were similar at 14 months.

CONCLUSIONS

Indices of cardiac size and function after the Norwood procedure are similar for modified Blalock-Taussig shunt and RVPAS by 14 months of age. Interstage differences between shunt types can likely be explained by the physiology created when the shunts are in place rather than by intrinsic differences in cardiac function.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00115934.

The effect of morphologic subtype on outcomes following the Sano-Norwood procedure

OBJECTIVES

Controversy exists concerning outcomes of patients with different morphologic subtypes of hypoplastic left heart syndrome undergoing the Norwood procedure, in particular, aortic atresia-mitral stenosis (AA-MS) patients receiving a systemic-pulmonary modified Blalock-Taussig (mBT) shunt. We sought to determine the influence of known risk factors and morphology on early survival in our cohort of Sano-Norwood patients with right ventricle-pulmonary artery (RV-PA) conduits as the source of pulmonary blood flow.

METHODS

We studied early survival in patients with Sano-modified Norwood procedures from 2002 to 2010 and included both typical and atypical (including unbalanced atrioventricular canal defect) morphologic variants. We included a comparison group composed of classical Norwood patients with mBT shunts.

RESULTS

Of 264 Sano-Norwood patients, 49 had AA-MS and 30 had atypical morphologies. Weight ≤ 2.5 kg was associated with a poorer 1-year survival (P = 0.0007), though ascending aorta (AscAo) size <2.0 mm was not. We did not observe a difference in 30-day or 1-year Kaplan-Meier (K-M) survival across typical morphologic variants for either a Sano or mBTS group. Atypical variants exhibited a trend towards lower 30-day and 1-year survival in both Sano and mBTS groups though this was not significant. Direct comparison of 30-day K-M survival for Sano versus mBTS in AA-MS patients showed similar outcomes (P = NS).

CONCLUSIONS

Use of the RV-PA conduit results in good early survival, even in those with a small AscAo size. Atypical morphologic variants seem to do worse irrespective of the Sano or mBTS group. Further studies will be required to determine conclusively whether the RV-PA shunt confers protective effects in the AA-MS subgroup compared with the mBTS.

Early developmental outcome in children with hypoplastic left heart syndrome and related anomalies: the single ventricle reconstruction trial

BACKGROUND

Survivors of the Norwood procedure may experience neurodevelopmental impairment. Clinical trials to improve outcomes have focused primarily on methods of vital organ support during cardiopulmonary bypass.

METHODS AND RESULTS

In the Single Ventricle Reconstruction trial of the Norwood procedure with modified Blalock-Taussig shunt versus right-ventricle-to-pulmonary-artery shunt, 14-month neurodevelopmental outcome was assessed by use of the Psychomotor Development Index (PDI) and Mental Development Index (MDI) of the Bayley Scales of Infant Development-II. We used multivariable regression to identify risk factors for adverse outcome. Among 373 transplant-free survivors, 321 (86%) returned at age 14.3 ± 1.1 (mean ± SD) months. Mean PDI (74 ± 19) and MDI (89 ± 18) scores were lower than normative means (each P<0.001). Neither PDI nor MDI score was associated with type of Norwood shunt. Independent predictors of lower PDI score (R(2)=26%) were clinical center (P=0.003), birth weight <2.5 kg (P=0.023), longer Norwood hospitalization (P<0.001), and more complications between Norwood procedure discharge and age 12 months (P<0.001). Independent risk factors for lower MDI score (R(2)=34%) included center (P<0.001), birth weight <2.5 kg (P=0.04), genetic syndrome/anomalies (P=0.04), lower maternal education (P=0.04), longer mechanical ventilation after the Norwood procedure (P<0.001), and more complications after Norwood discharge to age 12 months (P<0.001). We found no significant relationship of PDI or MDI score to perfusion type, other aspects of vital organ support (eg, hematocrit, pH strategy), or cardiac anatomy.

CONCLUSIONS

Neurodevelopmental impairment in Norwood survivors is more highly associated with innate patient factors and overall morbidity in the first year than with intraoperative management strategies. Improved outcomes are likely to require interventions that occur outside the operating room.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00115934.

Systemic oxygen transport derived by using continuous measured oxygen consumption after the Norwood procedure-an interim review

The balance between systemic O(2)consumption (VO(2)) and O(2)delivery (DO(2)) is impaired in children after cardiopulmonary bypass surgery, with decreased DO(2)and increased VO(2). The major goal, and the major challenge, of postoperative management has been to match DO(2)to VO(2)in order to sustain cellular metabolism, particularly in neonates after the Norwood procedure. While much effort has been put into augmenting cardiac output and DO(2), VO(2)remains largely ignored. Respiratory mass spectrometry allows the precise and continuous measurement of VO(2). Measured VO(2), using the direct Fick principle, allows for the calculation of each element of systemic O(2)transport in the complex Norwood circulation. The actual measurements of O(2)transport have allowed us, in the past five years or so, to extensively investigate the Norwood physiology in terms of the VO(2)-DO(2)relationship and the factors affecting it in clinical treatments. Therefore, the first objective of this article is to introduce the technique of respiratory mass spectrometry and its adaption to measure VO(2)across paediatric ventilators with continuous flow. The second objective is to give an interim review of the main findings in our studies on systemic O(2)transport in 17 neonates in the first 72 h after the Norwood procedure. These findings include the profiles of systemic O(2)transport, the important contribution of VO(2)to the impaired balance of O(2)transport and the complex effects of some routine clinical treatments on the VO(2)-DO(2)relationship (including catecholamines, PaCO(2), Mg(2+)and hyperglycaemia, as well as patient-specific anatomical variations). The influence of systemic O(2)transport on cerebral oxygenation is also introduced. This information may help us to refine postoperative management in neonates after the Norwood procedure. Our initial studies mark the end of the beginning, but much is yet explored. Ultimately, the resultant improved systemic and regional O(2)transport in the early postoperative period may have an important impact on long-term outcomes, thereby improving the quality of life for these vulnerable children.

Congenital heart surgeon's technical proficiency affects neonatal hospital survival

OBJECTIVE

Risk factors for mortality after neonatal cardiac surgery have been seldom studied. We sought to identify contemporary risk factors for mortality and the impact of surgical technical performance on surgical outcomes after neonatal cardiac surgery.

METHODS

We conducted a matched case-control study comparing 56 neonates who died after cardiac surgery (2002-2008) with 56 survivors matched by surgical procedure and year of surgery. Surgical efficacy for repair or palliation was graded using a reliable simple surgical technical score. Patient and surgical characteristics were compared for the survivors and nonsurvivors using paired analyses.

RESULTS

There was no significant difference between patients who died and their matched controls in terms of age, Aristotle score, Risk Adjustment in Congenital Heart Surgery-1 category, and single versus biventricular repair. When compared with survivors, patients who died were more likely to be premature (41% vs 5%, P < .001), to weigh less than 2.5 kg (25% vs 9%, P = .05), and to have inadequate surgical repair or palliation (55% vs 9%, P < .001). Cardiopulmonary bypass time was longer for the patients who died (median, 159 vs 133 minutes, P = .002). Highest postoperative lactate (median, 9.0 vs 6.0, P < .001), use of extracorporeal membrane oxygenation (71% vs 13%, P < .001), and reoperation during the same admission (75% vs 2%, P < .001) were also associated with death. In multivariable analysis, inadequate surgical repair or palliation (odds ratio, 11, P = .02) and need for postoperative extracorporeal membrane oxygenation (odds ratio, 5.1, P = .009) were the only risk factors associated with hospital death.

CONCLUSIONS

Our study highlights the need for optimal technical performance to minimize neonatal deaths. This has important implications when sustaining or developing a pediatric cardiac program.

Does the shunt type determine mid-term outcome after Norwood operation?

OBJECTIVES

With improved short-term outcomes the right ventricular to pulmonary artery shunt (Sano) has become the preferred pulmonary blood source in the Norwood procedure in many centres. However, most studies analysed consecutive cohorts, with a first modified Blalock-Taussig shunt (BT) followed by the Sano cohort. Besides, neither comprehensive preoperative risk analysis nor outcome beyond 1 year of age was investigated.

METHODS

This study reviews 109 neonates undergoing the Norwood procedure in the same interval between October 2002 and December 2009. The Sano (38) or BT shunt (71) was assigned according to the surgeon's preference. Two neonates subsequently underwent successful biventricular repair and were excluded. The Aristotle comprehensive score (ACS) was used to evaluate preoperative risk, with high-risk patients (n = 39) classified as having an ACS ≥ 20, and low-risk patients (n = 68) given an ACS <20.

RESULTS

Mean Aristotle score at the Norwood operation was 18.8 ± 0.4 and 18.9 ± 0.3 (P = 0.9) in Sano and BT, respectively. Mean follow-up interval was 4.1 ± 2.1 years (range: 1.7-8.9 years). Actuarial survival was similar, stabilizing from the 8th postoperative month onwards at 78.6 ± 4.9% (95% CI: 67.0-86.5%) for Sano and 78.4 ± 6.8% (95% CI: 61.4-88.6%) for BT; P = 0.95. Midterm actuarial survival was higher in low-risk patients, 88.2 ± 3.9% (95% CI: 77.8-93.9%) than in high-risk patients: 61.5 ± 7.8% (95% CI: 44.5-74.7%, P = 0.0003). No survival benefit was detected in low- or high-risk cases for either shunt type. Risk factors for midterm mortality were cardiorespiratory failure requiring ventilation (13/34, P = 0.004), and ACS ≥ 20 (15/39, P = 0.001), but not shunt type (8/37, P = 0.95). Increased number of shunt-related interventions before the Glenn procedure were noted with Sano (32.4 versus 6.5%, P = 0.002).

CONCLUSIONS

Preoperative risk factors, regardless of shunt type, influence midterm survival after the Norwood procedure with an excellent outcome in low-risk patients, while high-risk cases still incur a significant mortality. Sano shunt interventions occurred with increased numbers. Although, Sano shunt may be the only feasible option in some instances, given the possible negative effects of ventriculotomy on right ventricle function, the widespread use of Sano shunt should be reconsidered.

Acute ST changes during anesthesia induction 10 months after Norwood procedure

After the Norwood procedure for palliation of hypoplastic left heart syndrome, there is still significant interstage and late mortality with often unclear etiology. An important, but possibly under-recognized complication of the Norwood operation is the potential for coronary insufficiency from pre-coronary stenosis due to kinking or scarring at the anastomosis between the native and neo-aorta. We report a case of a clinically thriving 10-month old infant status post bidirectional Glenn who had acute ischemic changes on electrocardiogram (ECG) during induction of anesthesia for elective bilateral herniorrhaphy. A discrete narrowing in the native aorta to neo-aorta anastomosis was identified. A stent was placed emergently to restore adequate coronary blood flow after failure of simple angioplasty to adequately improve the stenosis.

Intermediate-term mortality and cardiac transplantation in infants with single-ventricle lesions: risk factors and their interaction with shunt type

OBJECTIVE

The study objective was to identify factors associated with death and cardiac transplantation in infants undergoing the Norwood procedure and to determine differences in associations that might favor the modified Blalock-Taussig shunt or a right ventricle-to-pulmonary artery shunt.

METHODS

We used competing risks methodology to analyze death without transplantation, cardiac transplantation, and survival without transplantation. Parametric time-to-event modeling and bootstrapping were used to identify independent predictors.

RESULTS

Data from 549 subjects (follow-up, 2.7 ± 0.9 years) were analyzed. Mortality risk was characterized by early and constant phases; transplant was characterized by only a constant phase. Early phase factors associated with death included lower socioeconomic status (P = .01), obstructed pulmonary venous return (P < .001), smaller ascending aorta (P = .02), and anatomic subtype. Constant phase factors associated with death included genetic syndrome (P < .001) and lower gestational age (P < .001). The right ventricle-to-pulmonary artery shunt demonstrated better survival in the 51% of subjects who were full term with aortic atresia (P < .001). The modified Blalock-Taussig shunt was better among the 4% of subjects who were preterm with a patent aortic valve (P = .003). Lower pre-Norwood right ventricular fractional area change, pre-Norwood surgery, and anatomy other than hypoplastic left heart syndrome were independently associated with transplantation (all P < .03), but shunt type was not (P = .43).

CONCLUSIONS

Independent risk factors for intermediate-term mortality include lower socioeconomic status, anatomy, genetic syndrome, and lower gestational age. Term infants with aortic atresia benefited from a right ventricle-to-pulmonary artery shunt, and preterm infants with a patent aortic valve benefited from a modified Blalock-Taussig shunt. Right ventricular function and anatomy, but not shunt type, were associated with transplantation.

Left ventricular hypoplasia: a spectrum of disease involving the left ventricular outflow tract, aortic valve, and aorta

"Hypoplastic left heart syndrome" is an unsatisfactory term describing lethal underdevelopment of the left ventricle (LV). It represents the more severe end of a spectrum of LV hypoplasia, mandating single-ventricle palliation or cardiac transplantation. Less severe "borderline" ventricular hypoplasia may instead allow various biventricular therapeutic strategies and better long-term outcomes. In this review, we consider factors causing and modifying the abnormal development of the LV. LV hypoplasia is typically seen in association with left ventricular outflow tract obstruction, itself part of a spectrum of related defects with common etiologies. Secondary responses to outflow obstruction are complex but involve abnormal flow dynamics and shear stresses that result in compromised and poorly orchestrated ventricular growth and development. Subsequent remodeling is likely influenced by genetic modifiers, including intrinsic myocardial growth signaling pathways, possibly including those of HAND transcription factors. In addition, during the latter stages of gestation, cardiomyocytes undergo a switch in myogenic potential and lose the ability to undergo mitosis. Ventricular hyperplasia can therefore no longer occur; remodeling is instead limited to muscular hypertrophy. Subtle differences in this switch in myogenic potential--and modulators thereof--are likely to be of clinical and therapeutic importance, especially in children with "borderline LVs" being considered for fetal interventions or post-natal biventricular repair strategies. Finally, by more clearly understanding the initiators and propagators of abnormal ventricular development, we can hope to lean away from grouping a heterogeneous group of infants together under the unsatisfactory term "hypoplastic left heart syndrome."

Hypoplastic left heart syndrome in context

Hypoplastic left heart syndrome is a rare condition requiring major cardiac surgery during the neonatal period to sustain life, with subsequent procedures culminating in completion of the Fontan circulation - the common pathway for all 'single ventricle' conditions. Algorithms for care of these children are now well defined with predictable medium-term outcomes with the majority achieving a Fontan circulation. Hypoplastic left heart syndrome is one of a group of conditions that require complex surgery as a neonate and require a similar perioperative approach. Antenatal diagnosis is common in this patient subgroup, and there is a significant body of work that can be drawn on to inform parental choice.

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.

Tricuspid valve repair in single ventricle: timing and techniques

Tricuspid valve performance in the systemic circulation is known to have important implications for survival and functional status after univentricular palliation of hypoplastic left heart syndrome (HLHS). Moderate to severe tricuspid valve regurgitation is not an uncommon finding in patients with HLHS undergoing staged surgical reconstruction. It can result from either abnormal valve morphology or incomplete leaflet coaptation, or both. But first and foremost, any aortic arch re-obstruction must be excluded. Development of significant tricuspid regurgitation (TR) remains an obstacle in improving survival after the Norwood procedure and likely compromised functional health after the Fontan procedure. Thus, surgical intervention for minimizing tricuspid valve deterioration and significant TR seems pivotal to improving long-term outcomes for patients with HLHS. This article provides an overview of the etiology and mechanisms of development of significant TR, natural history, indications for surgical intervention, and focuses on timing, techniques, and clinical outcomes of tricuspid valve repair in the setting of single ventricle.

Pediatric cardiovascular drug dosing in critically ill children and extracorporeal membrane oxygenation

Cardiovascular disease in children is common and results in significant morbidity and mortality. The sickest children with cardiovascular disease may require support with extracorporeal membrane oxygenation (ECMO), which provides life-saving assistance for children with refractory cardiorespiratory failure. Many classes of cardiovascular drugs are used in children, but very few of these agents have been well studied in children. The knowledge gap is even more pronounced in children supported by ECMO. Pharmacokinetic (PK) data collected to date (primarily from antibiotics and sedatives) suggest that the ECMO circuit has the potential to significantly alter the PK of drugs including changes in clearance and volume of distribution. Of all cardiovascular drugs administered to children supported by ECMO, only 11 have been partially studied and reported in the medical literature. Esmolol, amiodarone, nesiritide, bumetanide, sildenafil, and prostaglandin E1 seem to require dosing modifications in children supported by ECMO, whereas it seems that hydralazine, nicardipine, furosemide, epinephrine, and dopamine can be dosed similarly to children not supported by ECMO. However, trials evaluating the PK of these drugs in patients supported by ECMO are extremely limited (ie, case reports), and therefore, definitive dosing recommendations are not plausible. Research efforts should focus on evaluating the PK of drugs in patients on ECMO to avoid therapeutic failures or unnecessary toxicities.

Temporary restriction of right ventricle-pulmonary artery conduit flow using haemostatic clips following Norwood I reconstruction: potential for improved outcomes

Improved outcomes of the Norwood procedure in hypoplastic left heart syndrome have been achieved by the manipulation of the pulmonary:systemic flow ratio (Qp:Qs) in the early post-operative period, with focus on improving systemic perfusion. As an extension of this Qp:Qs-limiting strategy, we evolved a novel surgical technique to achieve transient flow restriction in the right ventricle-pulmonary artery (RV-PA) conduit for the first 48 h, using haemostatic clips, in a cohort of patients and compared the early outcomes with a non-clipped cohort. Clips were subsequently removed at 48 h at the time of definitive chest closure. We performed RV-PA shunt flow clipping in 37 patients; 75 historical controls had not received clips. Groups were matched for weight, size of ascending aorta, anatomy and circulatory arrest times. Thirty-day mortality was lower in the clipped cohort (2 of 37; 5.4%) versus the unclipped cohort (10 of 75; 13.3%). The minimum blood lactate levels within the first 24 h post-surgery in the unclipped group were significantly higher (P = 0.049), with a significantly lower Qp:Qs in the first 6 h in the clipped patients. These data suggest that limiting Qp:Qs in the early post-operative period following the Norwood procedure may help in the post-operative management of these difficult patients. These results warrant further study.

Echocardiographic evaluation of the single right ventricle in congenital heart disease: results of new techniques

Right ventricular (RV) function is increasingly recognized as having prognostic significance in various disease processes. The current gold standard for noninvasive measurement of RV function is cardiac magnetic resonance imaging; however, because of practical considerations, echocardiography remains the most often used modality for evaluating the RV. In the past, because of its complex morphology, echocardiographic assessment of the RV was usually qualitative in nature. Current advances in echocardiographic techniques have been able to overcome some of the previous limitations and thus quantification of RV function is increasingly being performed. In addition, recent echocardiographic guidelines for evaluating the RV have been published to aid in standardizing practice. The evaluation of RV function almost certainly has no greater importance than in the congenital heart population, especially in those patients that have a single RV acting as the systemic ventricle. As this complex population continues to increase in number, accurate and precise evaluation of RV function will be a major issue in determining clinical care.

Outcomes of hypoplastic left heart syndrome in low-birth-weight patients

The objective of this study was to assess outcomes of hypoplastic left heart syndrome (HLHS) patients weighing ≤ 2.5 kg throughout staged palliation. We performed a single-center retrospective review. Abstracted data included gestational age, birth weight, presence of noncardiac anomalies, and survival through Fontan. Fifty-two patients met inclusion criteria, with a median birth weight of 2.14 kg and gestational age of 36 weeks. Five patients received comfort care only. Of 47 patients who underwent initial surgical palliation, 51% survived to initial hospital discharge. Birth weight and gestational age (GA) were similar between survivors and nonsurvivors. Compared with survivors, risk factors for death prior to initial hospital discharge were as follows: small for GA (P = 0.005), noncardiac anomalies (P = 0.04), need for post-perative extracorporeal membrane oxygenation (P = 0.0004), and conversion from initial palliation to Sano shunt (n = 5, no survivors). Operative survival following Stage 2 palliation was 91% (21/23) and 94% after Fontan (17/18). Overall survival for palliated patients from birth through Fontan was 36%. Low-birth-weight neonates with HLHS have poor overall survival through the Fontan operation, with highest mortality following Stage 1 palliation. Being small for GA and the presence of noncardiac anomalies are important preoperative risk factors for early mortality.

Feeding, growth, nutrition, and optimal interstage surveillance for infants with hypoplastic left heart syndrome

Improvement in operative survival of patients with hypoplastic left heart syndrome has led to increasing emphasis on prevention of interstage mortality. Many centres have improved interstage results through programmes of home monitoring following discharge after the Norwood (Stage 1) operation. Experience with heightened interstage surveillance has identified failure to thrive during infancy as a modifiable risk factor for this population, one that has been linked to concerning outcomes at subsequent palliative surgeries. Ensuring normal growth as an infant has thus become a priority of management of patients with functionally univentricular hearts. Herein, we review the existing evidence for best practices in interstage surveillance and optimal nutrition in infants with functionally univentricular hearts. In addition, we highlight data presented at HeartWeek 2011, from Cardiology 2011, the 15th Annual Update on Pediatric and Congenital Cardiovascular Disease, and the 11th Annual International Symposium on Congenital Heart Disease.

Informed consent, bioethical equipoise, and hypoplastic left heart syndrome

In utero diagnosis of complex progressive cardiac disease such as hypoplastic left heart syndrome presents a novel opportunity for antepartum, intrapartum, and neonatal management. The clinical possibilities and potential for differing outcomes challenge the mother-foetus dyad with regard to informed consent. Previous studies reveal that rates of termination of pregnancy for foetuses with hypoplastic left heart syndrome vary widely in the United States and Europe, leading us to surmise that informed consent may be practised differently. The purpose of this paper is to review the ethical considerations and physician responsibilities of informed consent as they relate to prenatal and postnatal patients with hypoplastic left heart syndrome. Special consideration is paid to the informed consent process as practised by the obstetrician, perinatologist, paediatric cardiologist, and paediatric cardiac surgeon as it relates to termination of pregnancy, comfort care, and surgical palliation. We will argue that informed consent as it relates to hypoplastic left heart syndrome is far from standardised and that there exists a state of bioethical equipoise concerning the extent and limits of its application in the current clinical setting.

Effects of health disparities on survival after neonatal heart surgery: why should racial, ethnic, gender, and socioeconomic status be included in the risk analysis?

Health disparities are "differences in the quality of health and health care across different populations." Potential disparities associated with race, ethnicity, gender, and socioeconomic status should be considered when attempting to develop models for survival and neurodevelopmental outcomes in neonates undergoing congenital heart surgery. Each of the aforementioned sociodemographic factors is related to postsurgical mortality because they are frequently linked to measures of access to care in addition to location of care (geographically) and the type of institution (teaching vs. nonteaching) where patients receive care. Traditionally these factors have not been considered in models of surgical treatment outcomes in conditions such as hypoplastic left heart syndrome. However, we believe these factors should at least be included in risk analysis models to help explain their impact on outcomes and in predicting outcomes. Therefore, the purpose of this article is to highlight some of the nonsurgical influences that affect survival after neonatal heart surgery such as race, ethnicity, gender, and socioeconomic status.

Neonatal surgical reconstruction and peri-operative care for hypoplastic left heart syndrome: current strategies

The management of newborns with hypoplastic left heart syndrome has changed significantly over the past three decades, with an associated dramatic improvement in outcomes. The aim of this paper is to discuss current peri-operative and palliative surgical strategies. Owing to the fact that comparative outcomes for these strategies have been addressed in a limited number of prospective trials and extractions from multi-centred databases, the primary focus of this review is descriptive.

Neurodevelopment and quality of life for children with hypoplastic left heart syndrome: current knowns and unknowns

The aim of this review is to describe the current state of knowledge related to neurodevelopmental outcomes and quality of life for children with hypoplastic left heart syndrome and to explore future questions to be answered for this group of children.

Changing attitudes to the management of hypoplastic left heart syndrome: a European perspective

BACKGROUND AND AIMS

Several years ago, one of us described the difference in attitude to patients with hypoplastic left heart syndrome in the United States of America and Europe as similar to that between Mars and Venus. Uncertainty remains with regard to the long-term prognosis for patients with hypoplastic left heart syndrome. This prognosis may be considered in terms of survival, functional performance, including exercise capacity and neurodevelopment, as well as psychosocial effects on the patient, family, and siblings. Counselling parents where either an antenatal or postnatal diagnosis of hypoplastic left heart syndrome has been made requires practitioners to give information on these prognostic aspects. We wanted to see how attitudes among European surgeons have changed over the last few years.

METHODS

We performed a review of recent European data for hypoplastic left heart syndrome and conducted a survey among surgeons in major European centres to ascertain key aspects of their attitudes to the management of patients with hypoplastic left heart syndrome and how they counsel parents.

RESULTS AND CONCLUSIONS

As of January, 2011, 2392 citations in the PubMed database were available for the search string "hypoplastic left heart". The majority of these were from the centres from the United States of America and Europe. The European Association for Cardio-Thoracic Surgery Congenital Heart Surgery Database shows an annual increase in the number of Norwood (Stage I) operations for hypoplastic left heart syndrome from 2003 to 2009, with a corresponding reduction in mortality. European rates of antenatal detection vary widely between centres, as do the rates of termination for a prenatal diagnosis of hypoplastic left heart syndrome. We observed a wide variation in the estimates of surgeons for survival and quality of life for surgical palliation of hypoplastic left heart syndrome, as well as in their estimates for actual rates of termination of pregnancy in their centres. Further, there was marked inconsistency in the information given to parents as part of the process of counselling. These issues remain to be resolved if parents are to make a fully informed decision for their child.

Lessons from inter-stage cardiac magnetic resonance imaging in predicting survival for patients with hypoplastic left heart syndrome

This study describes single-unit experience and explores risk stratification, with protocolised inter-stage cardiac magnetic resonance imaging for infants with hypoplastic left heart syndrome. Survival was retrospectively analysed among the cohort of locally followed survivors of Norwood Stage I procedure, who underwent magnetic resonance imaging under general anaesthesia from 2003 to 2008. This included 32 patients: 17 with Sano conduit and 15 with arterio-pulmonary shunt. The median (inter-quartile range) age and weight at scan were 3.1 (2.6-4.6) months and 5.0 (4.5-5.3) kilograms, respectively. Using morphologic definitions, the median coarctation index was 0.71 (0.57-0.83). The degree of proximal right and left pulmonary artery narrowing was 25% (14-44%) and 25% (11-50%), respectively. The median right ventricular ejection fraction was 54% (48-59%). The ejection fraction was not related to the coarctation index or to pulmonary artery narrowing. Patients were followed up for a median of 19.2 (10.8-46.0) months, during which 13 (41%) had an intervention in addition to routine Norwood Stage II surgery and seven died. Risk of death was related to reduced right ventricular ejection fraction, with a hazard ratio of 0.91 (95% confidence interval 0.85-0.98, p = 0.02), and the cumulative number of focal stenoses of neo-aortic arch and pulmonary arteries (hazard ratio 2.71, 95% confidence interval 1.14-6.44, p = 0.02).

CONCLUSIONS

In addition to comprehensive three-dimensional morphologic imaging, inter-stage cardiac magnetic resonance imaging provides a ventricular functional index that may predict outcome in patients with hypoplastic left heart syndrome. Measures to preserve right ventricular systolic function and relieve stenoses are paramount within the complex management strategies for these patients.

Perioperative care of the infant with single ventricle physiology

OPINION STATEMENT

Among patients with congenital heart defects, neonates with single ventricle disease continue to challenge clinicians despite significant improvements in survival over the past 30 years. The cardiac anatomical variants associated with the term "single ventricle" are characterized by severe hypoplasia (or absence) of either ventricle, typically in association with obstruction or atresia of either the pulmonary or systemic outflow tracts. Physiologically, the single ventricle receives both pulmonary and systemic venous blood and ejects simultaneously into the pulmonary and systemic circulations, a pattern commonly referred to as single ventricle physiology. Medical and surgical management strategies, though palliative, are aimed at achieving the optimal balance of systemic blood flow and pulmonary blood flow to maximize oxygen delivery. Patients with single ventricle physiology have a greater risk of dying than those with biventricular circulations and are generally committed to multiple palliative interventions throughout childhood with considerable risk. Surgical intervention in the newborn period involves Norwood Stage I palliation, placement of a systemic-to-pulmonary artery shunt, or banding of the pulmonary artery, depending on the status of the outflow tracts. Heart transplantation is offered as the initial approach in some centers. The management strategy and the actual delivery of care from the time of birth (or at time of diagnosis) through the postoperative period is crucial to optimize the short-term and long-term outcomes. Whereas survival following initial palliation in experienced centers is as high as 95%, emphasis is now appropriately shifting toward the control of in-hospital morbidity and optimizing long-term functional outcome. Centers are continually striving to gather and apply new knowledge related to the underlying anatomical and physiologic problems while seeking to improve decision making and care of the patient with single ventricle physiology.

Inpatient costs and charges for surgical treatment of hypoplastic left heart syndrome

OBJECTIVE

Hypoplastic left heart syndrome (HLHS) is one of the most serious congenital cardiac anomalies. Typically, it is managed with a series of 3 palliative operations or cardiac transplantation. Our goal was to quantify the inpatient resource burden of HLHS across multiple academic medical centers.

METHODS

The University HealthSystem Consortium is an alliance of 101 academic medical centers and 178 affiliated hospitals that share diagnostic, procedural, and financial data on all discharges. We examined inpatient resource use by patients with HLHS who underwent a staged palliative procedure or cardiac transplantation between 1998 and 2007.

RESULTS

Among 1941 neonates, stage 1 palliation (Norwood or Sano procedure) had a median length of stay (LOS) of 25 days and charges of $214,680. Stage 2 and stage 3 palliation (Glenn and Fontan procedures, respectively) had median LOS and charges of 8 days and $82,174 and 11 days and $79,549, respectively. Primary neonatal transplantation had an LOS of 87 days and charges of $582,920, and rescue transplantation required 36 days and $411,121. The median inpatient wait time for primary and rescue transplants was 42 and 6 days, respectively. Between 1998 and 2007, the LOS for stage 1 palliation increased from 16 to 28 days and inflation-adjusted charges increased from $122,309 to $280,909, largely because of increasing survival rates (57% in 1998 and 83% in 2007).

CONCLUSIONS

Patients with HLHS demand considerable inpatient resources, whether treated with the Norwood-Glenn-Fontan procedure pathway or cardiac transplantation. Improved survival rates have led to increased hospital stays and costs.

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.

Hypoplastic left heart syndrome and aortic atresia-mitral stenosis variant: role of myocardial protection strategy and impact of ventriculo-coronary connections after stage I palliation

Aortic atresia-mitral stenosis (AA-MS) has been implicated as a determinant of outcome after Stage-1 palliation (S1P) in hypoplastic left heart syndrome (HLHS).Studies evaluating the association of AA-MS with ventriculo-coronary connections (VCC) and mortality report conflicting results. The significance of VCC, myocardial protection, and shunt strategy after S1P has yet to be determined. Between January 2005 and July 2009, 100 neonates with HLHS underwent S1P. Mitral and aortic valves and presence of VCC were assessed. Antegrade continuous cold blood cardioplegia was administered throughout the vast extent of the neo-aortic reconstruction. A right ventricle-to-pulmonary shunt was used for an ascending aortic diameter of 0.6 mm/kg or less. Survival analysis was performed to determine predictors and assess impact of AA-MS and VCC on hospital and interstage mortality. Twenty-seven (of 100) patients had AA-MS. The mean age and weight at S1P were 6.5 ± 2.8 days and 3.09 ± 0.47 kg, respectively. VCC were found in 56% of AA-MS. Twenty-two had Norwood-Sano, 3 had classic Norwood, and 2 had hybrid S1P. VCC were associated with AA-MS, endocardial fibroelastosis, and ascending aortic size <2 mm (P < 0.05) but not higher mortality (P = ns). Operative and interstage survival for AA-MS after S1P was 85.2 and 71%, respectively (not statistically different compared to all other subtypes; P = ns). Actuarial survival after S1P at 1, 3, 6, 12, and 36 months was 92.9 ± 4.9, 78.6 ± 7.8, 75 ± 8.2, 71.3 ± 8.3, and 71.3 ± 8.3%, respectively. Intact atrial septum and post-S1P renal dysfunction (P < 0.05) were independent predictors of hospital and interstage mortality. In patients with HLHS, AA-MS carries no survival disadvantage after S1P during the hospital and interstage period regardless of VCC. Intact atrial septum and post-S1P renal dysfunction predict early and interstage mortality. Myocardial protection and shunt strategy might influence the outcome in this HLHS variant.

Management of the postoperative pediatric cardiac surgical patient

OBJECTIVE

To review the salient aspects and latest advances in the management of the postoperative pediatric cardiac patient.

DATA SOURCE

A Medline-based literature source.

CONCLUSION

The practice of pediatric cardiac intensive care has evolved considerably over the last several years. These efforts are the result of a collaborative effort from all subspecialties involved in the care of pediatric patients with congenital heart disease. Discoveries and innovations that are representative of this effort include the extension of cerebral oximetry from the operating room into the critical care setting; mechanical circulatory devices designed for pediatric patients; and surgery in very low birth weight neonates. Advances such as these impact postoperative management and make the field of pediatric cardiac intensive care an exciting, demanding, and evolving discipline, necessitating the ongoing commitment of various disciplines to pursue a greater understanding of disease processes and how to best go about treating them.

Complications after the Norwood operation: an analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

BACKGROUND

Limited multicenter data exist regarding the prevalence of postoperative complications after the Norwood operation and their associated mortality risk.

METHODS

We evaluated infants in The Society of Thoracic Surgeons Congenital Heart Surgery Database who underwent the Norwood operation from 2000 to 2009. The prevalence of postoperative complications after the Norwood operation and associated in-hospital mortality were described. Patient factors associated with complications were evaluated in multivariable analyses.

RESULTS

A total of 2,557 patients from 53 centers were included. Median age at operation was 6 days (interquartile range, 4 to 9 days) and 90% had a right dominant ventricle. Overall mortality was 22%, and 75% had 1 complication or more. Mortality increased with increasing number of complications: 1 complication, 17%; 2 complications, 21%; 3 complications, 26%; 4 complications, 33%; and 5 or more complications, 45%. Renal and cardiovascular complications carried the greatest mortality risk. Patient factors associated with 1 complication or more included weight less than 2.5 kg (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.2 to 2.1), single right versus single left ventricle (OR, 1.4; 95% CI, 1.01 to 2.0), preoperative shock (OR, 1.5; 95% CI, 1.1 to 2.1), non-cardiac/genetic abnormality (OR, 1.5; 95% CI, 1.2 to 1.9), and preoperative mechanical ventilatory (OR, 1.3; 95% CI, 1.03 to 1.6) or circulatory (OR 4.0; 95%CI, 1.6 to 10.2) support.

CONCLUSIONS

Complications after the Norwood operation are common, carry significant mortality risk, and are associated with several preoperative patient characteristics. These data may aid in providing prognostic information to families and in guiding quality improvement initiatives.

Cavopulmonary assist: (em)powering the univentricular fontan circulation

Since the Fontan/Kreutzer procedure was introduced, evolutionary clinical advances via a staged surgical reconstructive approach have markedly improved outcomes for patients with functional single ventricle. However, significant challenges remain. Early stage mortality risk seems impenetrable. Serious morbidities - construed as immutable consequences of palliation - have hardly been addressed. Late functional status is increasingly linked to pathophysiologic consequences of prior staged procedures. As more single-ventricle patients survive into adulthood, Fontan failure is emerging as an intractable problem for which there is no targeted therapy. Incremental solutions to address these ongoing problems have not had a measurable impact. Therefore, a fundamental reconsideration of the overall approach is reasonable and warranted. The ability to provide a modest pressure boost (2 to 6 mmHg) to existing blood flow at the total cavopulmonary connection can effectively restore more stable biventricular status. This would impact not only treatment of late Fontan failure, but also facilitate early surgical repair. A realistic means to provide such a pressure boost has never been apparent. Recent advances are beginning to unravel the unique challenges that must be addressed to realize this goal, with promise to open single-ventricle palliation to new therapeutic vistas.

Staged single-ventricle palliation in 2011: outcomes and expectations

Outcomes for staged palliation for single-ventricle heart disease have improved over the past two decades. As outcomes improve, parental expectations for survival and quality of life have risen accordingly. Nevertheless, the number of interventions and complications these patients must endure remain high. The final surgical destination of the single-ventricle patient, the total cavopulmonary connection (or Fontan operation) successfully separates systemic venous and pulmonary venous blood flow but does so at great cost. Fontan patients remain at significant risk of complications despite what are perceived to be "favorable" hemodynamics. The outcomes in this population are discussed in this review, with particular attention to the history behind our current strategies as well as to recent salient studies.