Staged surgical palliation in hypoplastic left heart syndrome and its variants

Mitochondrial Respiration Defects in Single-Ventricle Congenital Heart Disease

Background: Congenital heart disease (CHD) with single-ventricle (SV) physiology is now survivable with a three-stage surgical course ending with Fontan palliation. However, 10-year transplant-free survival remains at 39–50%, with ventricular dysfunction progressing to heart failure (HF) being a common sequela. For SV-CHD patients who develop HF, undergoing the surgical course would not be helpful and could even be detrimental. As HF risk cannot be predicted and metabolic defects have been observed in Ohia SV-CHD mice, we hypothesized that respiratory defects in peripheral blood mononuclear cells (PBMCs) may allow HF risk stratification in SV-CHD.

Methods: SV-CHD (n = 20), biventricular CHD (BV-CHD; n = 16), or healthy control subjects (n = 22) were recruited, and PBMC oxygen consumption rate (OCR) was measured using the Seahorse Analyzer. Respiration was similarly measured in Ohia mouse heart tissue.

Results: Post-Fontan SV-CHD patients with HF showed higher maximal respiratory capacity (p = 0.004) and respiratory reserve (p < 0.0001), parameters important for cell stress adaptation, while the opposite was found for those without HF (reserve p = 0.037; maximal p = 0.05). This was observed in comparison to BV-CHD or healthy controls. However, respiration did not differ between SV patients pre- and post-Fontan or between pre- or post-Fontan SV-CHD patients and BV-CHD. Reminiscent of these findings, heart tissue from Ohia mice with SV-CHD also showed higher OCR, while those without CHD showed lower OCR.

Conclusion: Elevated mitochondrial respiration in PBMCs is correlated with HF in post-Fontan SV-CHD, suggesting that PBMC respiration may have utility for prognosticating HF risk in SV-CHD. Whether elevated respiration may reflect maladaptation to altered hemodynamics in SV-CHD warrants further investigation.

Early postoperative interventional aortic valve closure for severe aortic regurgitation in a neonate after Norwood procedure

A neonate presented with signs of heart failure early after a Norwood procedure, due to increase of aortic and mitral valve regurgitation. Because repeated surgery was considered risky, we closed the aortic valve by catheter intervention with an Amplatzer Duct Occluder. Aortic regurgitation was abolished almost completely and the child improved. Unfortunately, 2 weeks after discharge, the patient died suddenly.

The Genetic Landscape of Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is one of the most lethal congenital heart defects, and remains clinically challenging. While surgical palliation allows most HLHS patients to survive their critical heart disease with a single-ventricle physiology, many will suffer heart failure, requiring heart transplantation as the only therapeutic course. Current paradigm suggests HLHS is largely of hemodynamic origin, but recent findings from analysis of the first mouse model of HLHS showed intrinsic cardiomyocyte proliferation and differentiation defects underlying the left ventricular (LV) hypoplasia. The findings of similar defects of lesser severity in the right ventricle suggest this could contribute to the heart failure risks in surgically palliated HLHS patients. Analysis of 8 independent HLHS mouse lines showed HLHS is genetically heterogeneous and multigenic in etiology. Detailed analysis of the Ohia mouse line accompanied by validation studies in CRISPR gene-targeted mice revealed a digenic etiology for HLHS. Mutation in Sap130, a component of the HDAC repressor complex, was demonstrated to drive the LV hypoplasia, while mutation in Pcdha9, a protocadherin cell adhesion molecule played a pivotal role in the valvular defects associated with HLHS. Based on these findings, we propose a new paradigm in which complex CHD such as HLHS may arise in a modular fashion, mediated by multiple mutations. The finding of intrinsic cardiomyocyte defects would suggest hemodynamic intervention may not rescue LV growth. The profound genetic heterogeneity and oligogenic etiology indicated for HLHS would suggest that the genetic landscape of HLHS may be complex and more accessible in clinical studies built on a familial study design.

Characteristics and outcomes of children with ductal-dependent congenital heart disease and esophageal atresia/tracheoesophageal fistula: A multi-institutional analysis

BACKGROUND

Extracardiac birth defects are associated with worse outcomes in congenital heart disease (CHD). The impact of esophageal atresia/trachea-esophageal fistula (EA/TEF) on outcomes after surgery for ductal-dependent CHD is unknown.

METHODS

Retrospective matched cohort study using the Pediatric Health Information System database from 07/2004 to 06/2015. Hospitalizations with ductal-dependent CHD and EA/TEF, undergoing CHD surgery were included as cases. Admissions with ductal-dependent CHD without EA/TEF were matched 3:1 for age at admission and Risk Adjustment for Congenital Heart Surgery-1 classification. Comparisons were performed using generalized estimating equations.

RESULTS

There were 124 cases and 372 controls. Cases included 32 (25.8%) low-risk, 86 (69.3%) intermediate-risk, and 6 (4.8%) high-risk patients. Cases had more females compared to controls (53.2% vs 41.1%, P = .022). Cases were more likely to be premature (28.2% vs 13.7%, P = .001) and low birth weight (29.8% vs 11.8%, P < .001). Cases had a similar frequency of Down syndrome, and DiGeorge/Velocardiofacial syndrome, but a higher frequency of anorectal malformations (4.3% vs 2.4%, P < .001) and renal anomalies (27.4% vs 9.9%, P < .001) than controls. Cases had a higher mortality on univariate (22.0% vs 8.4%, P < .001) and multivariable analysis (odds ratio 2.45, 95%, confidence interval 1.34 - 4.49). Prematurity also was significantly associated with mortality on multivariable analysis. Cases had a longer duration of mechanical ventilation, longer hospital duration of stay, and higher total cost than controls (all P < .001).

CONCLUSION

In children with ductal-dependent CHD, EA/TEF is associated with increased morbidity, mortality and resource utilization. A majority of patients undergo EA/TEF repair prior to congenital heart disease surgery. (Surgery 2017;160:XXX-XXX.).

The Optimal Timing of Stage 2 Palliation for Hypoplastic Left Heart Syndrome: An Analysis of the Pediatric Heart Network Single Ventricle Reconstruction Trial Public Data Set

BACKGROUND

In infants requiring 3-stage single-ventricle palliation for hypoplastic left heart syndrome, attrition after the Norwood procedure remains significant. The effect of the timing of stage 2 palliation (S2P), a physician-modifiable factor, on long-term survival is not well understood. We hypothesized that an optimal interval between the Norwood and S2P that both minimizes pre-S2P attrition and maximizes post-S2P survival exists and is associated with individual patient characteristics.

METHODS

The National Institutes of Health/National Heart, Lung, and Blood Institute Pediatric Heart Network Single Ventricle Reconstruction Trial public data set was used. Transplant-free survival (TFS) was modeled from (1) Norwood to S2P and (2) S2P to 3 years by using parametric hazard analysis. Factors associated with death or heart transplantation were determined for each interval. To account for staged procedures, risk-adjusted, 3-year, post-Norwood TFS (the probability of TFS at 3 years given survival to S2P) was calculated using parametric conditional survival analysis. TFS from the Norwood to S2P was first predicted. TFS after S2P to 3 years was then predicted and adjusted for attrition before S2P by multiplying by the estimate of TFS to S2P. The optimal timing of S2P was determined by generating nomograms of risk-adjusted, 3-year, post-Norwood, TFS versus the interval from the Norwood to S2P.

RESULTS

Of 547 included patients, 399 survived to S2P (73%). Of the survivors to S2P, 349 (87%) survived to 3-year follow-up. The median interval from the Norwood to S2P was 5.1 (interquartile range, 4.1-6.0) months. The risk-adjusted, 3-year, TFS was 68±7%. A Norwood-S2P interval of 3 to 6 months was associated with greatest 3-year TFS overall and in patients with few risk factors. In patients with multiple risk factors, TFS was severely compromised, regardless of the timing of S2P and most severely when S2P was performed early. No difference in the optimal timing of S2P existed when stratified by shunt type.

CONCLUSIONS

In infants with few risk factors, progressing to S2P at 3 to 6 months after the Norwood procedure was associated with maximal TFS. Early S2P did not rescue patients with greater risk factor burdens. Instead, referral for heart transplantation may offer their best chance at long-term survival.

CLINICAL TRIAL REGISTRATION

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

Current Practices in the Timing of Stage 2 Palliation

BACKGROUND

Mortality through single-ventricle palliation remains high and the effect of the timing of stage 2 palliation (S2P) is not well understood. We investigated current practice patterns in the timing of S2P across two professional societies and compared them to actual practice patterns from two databases of patients who underwent S2P.

METHODS

A ten-question survey was distributed to the members of the Congenital Heart Surgeons' Society (CHSS) and the European Congenital Heart Surgeons' Association (ECHSA). Results were summarized using descriptive statistics. Surgeon-reported preferences were compared to clinical data from the CHSS Critical Left Ventricular Outflow Tract Obstruction (LVOTO) Registry and the Pediatric Heart Network Single Ventricle Reconstruction (SVR) database.

RESULTS

Overall, 38% (88 of 232) of surgeons from 74 institutions responded, of which 70% (62 of 88) were CHSS members and 30% (26 of 88) were ECHSA members. Surgeons reported performing S2P at a median of five months after stage 1 (interquartile range [IQR]: 4.5-6), with no difference between CHSS and ECHSA surgeons. Surgeons reported performing nonelective S2P at a median of 4.5 months after stage 1 (IQR: 3.5-5.5), again with no difference by society. No difference existed between the surgeon-reported preferences and patient data in the Critical LVOTO and SVR databases for the timing of elective (5 vs 5.1 vs 5.3 months, P = .19) or nonelective S2P (4.5 vs 4.6 vs 4.2 months, P = .06).

CONCLUSION

There was a remarkable lack of variation in surgeon preferences regarding the timing of S2P. This may represent a natural standardization of practice across congenital heart surgery, which is notable, given the current lack of guidelines regarding the timing of S2P.

Laparoscopic colectomy in an adult with single ventricle physiology: anesthetic implications and management

Increasing numbers of adult patients with complex congenital heart conditions are presenting for noncardiac surgery later in life. These disorders can present challenges for surgical and anesthesia providers. Specifically, single ventricle lesions offer anatomic and physiologic concerns during the perioperative period. Single ventricle physiology represents a delicate balance between systemic and pulmonary blood flow. Any alterations in blood flow through these systems can produce undesirable hemodynamic changes, especially during the perioperative period. We present a case of an adult patient with a single left ventricle who presented for laparoscopic total colectomy due to inflammatory bowel disease. His abnormal anatomy coupled with the hemodynamic disruptions caused by laparoscopy presented significant anesthetic challenges. We highlight the anesthetic concerns of single ventricle physiology, specifically pertaining to laparoscopic surgery. We provide recommendations for safely managing these patients perioperatively. With detailed preoperative evaluation and close hemodynamic monitoring during the perioperative period, these patients can experience successful surgical and anesthetic outcomes.

Long-term progression and survival following Norwood Single Ventricle Reconstruction

PURPOSE OF REVIEW

Much data exist concerning Norwood discharge mortality. Less is known about late survival. Examining the available data in light of the Single Ventricle Reconstruction trial is insightful as focus shifts toward long-term survival.

RECENT FINDINGS

Data from 2000 to 2001 demonstrated approximately 40-50% 10-year survival, 30-40% or less between 10 and 15 years. The shape of the curves was characteristic; the majority of deaths within the first year, followed by a late constant phase. Publications from 2001 to 2005 suggested that various combinations of technical and perioperative modifications allowed hospital discharge survivals as high as 90-94%. As results matured (2005-2010) a consistent message was that, although the shape of the newer curves was similar (highest hazard in the first 1 year), higher hospital survival shifted the later phase to yield better long-term survival (70-85% between 5 and 10 years). Some emphasized right ventricle-based shunts as a 'cause' of improving results. Since 2010, the Single Ventricle Reconstruction trial has matured and has increasingly shifted opinion away from the right ventricle shunt as a 'cause' of improved results. The survival of the right ventricle shunt group is slightly higher at 3 years, but the 1-year statistical significance has been lost and the two groups converge. As the Single Ventricle Reconstruction study was based on the interaction between randomized shunt and survival, the secondary and other endpoint analyses must be cautiously considered.

SUMMARY

The current English-language literature suggests a 60-80% 5-10 year survival expectation. The shape of the survival curve remains; the highest hazard remains the first year before a later, stable phase is reached. Rather than a 'magic bullet' theory surrounding one technique or practice, centers have differentially adopted various combinations to optimize Norwood survival. Optimizing interstage I survival is a challenge to further increase the percentage of patients reaching the late, stable phase.

Fetal aortic valvuloplasty for evolving hypoplastic left heart syndrome: postnatal outcomes of the first 100 patients

BACKGROUND

Fetal aortic valvuloplasty can be performed for severe midgestation aortic stenosis in an attempt to prevent progression to hypoplastic left heart syndrome (HLHS). A subset of patients has achieved a biventricular (BV) circulation after fetal aortic valvuloplasty. The postnatal outcomes and survival of the BV patients, in comparison with those managed as HLHS, have not been reported.

METHODS AND RESULTS

We included 100 patients who underwent fetal aortic valvuloplasty for severe midgestation aortic stenosis with evolving HLHS from March 2000 to January 2013. Patients were categorized based on postnatal management as BV or HLHS. Clinical records were reviewed. Eighty-eight fetuses were live-born, and 38 had a BV circulation (31 from birth, 7 converted after initial univentricular palliation). Left-sided structures, namely aortic and mitral valve sizes and left ventricular volume, were significantly larger in the BV group at the time of birth (P<0.01). After a median follow-up of 5.4 years, freedom from cardiac death among all BV patients was 96±4% at 5 years and 84±12% at 10 years, which was better than HLHS patients (log-rank P=0.04). There was no cardiac mortality in patients with a BV circulation from birth. All but 1 of the BV patients required postnatal intervention; 42% underwent aortic or mitral valve replacement. On the most recent echocardiogram, the median left ventricular end-diastolic volume z score was +1.7 (range, -1.3 to +8.2), and 80% had normal ejection fraction.

CONCLUSIONS

Short- and intermediate-term survival among patients who underwent fetal aortic valvuloplasty and achieved a BV circulation postnatally is encouraging. However, morbidity still exists, and ongoing assessment is warranted.

Effects of race, ethnicity, and gender on surgical mortality in hypoplastic left heart syndrome

Information is limited regarding the effect of race, ethnicity, and gender on the outcomes of the three palliative procedures for hypoplastic left heart syndrome (HLHS). This study examined the effects of race, ethnicity, gender, type of admission, and surgical volume on in-hospital mortality associated with palliative procedures for HLHS between 1998 and 2007 using data from the University HealthSystem Consortium. According to the data, 1,949 patients underwent stage 1 palliation (S1P) with a mortality rate of 29 %, 1,279 patients underwent stage 2 palliations (S2P) with a mortality rate of 5.4 %, and 1,084 patients underwent stage 3 palliation (S3P) with a mortality rate of 4.1 %. The risk factors for increased mortality with S1P were black and "other" race, smaller surgical volume, and early surgical era. The only risk factors for increased mortality with S2P were black race (11 % mortality; odds ratio [OR], 3.19; 95 % confidence interval [CI] 1.69-6.02) and Hispanic ethnicity (11 % mortality; OR 3.30; 95 % CI 1.64-6.64). For S2P, no racial differences were seen in the top five surgical volume institutions, but racial differences were seen in the non-top-five surgical volume institutions. Mortality with S1P was significantly higher for patients discharged after birth (37 vs 24 %; p = 0.004), and blacks were more likely to be discharged after birth (12 vs 5 % for all other races; p < 0.001). No racial differences with S3P were observed. The risk factors for increased mortality at S1P were black and "other" race, smaller surgical volume, and early surgical era. The risk factors for increased in-hospital mortality with S2P were black race and Hispanic ethnicity.

Laparoscopic antireflux surgery in infants with single ventricle physiology: a review

Laparoscopic fundoplication and gastrostomy tube placement have grown in popularity within the pediatric population for treatment of gastroesophageal reflux disease and failure to thrive, respectively. One population that has an increased need for gastric surgery in infancy is patients with congenital heart defects, especially those with "single ventricle physiology." The most common defect included in this population is hypoplastic left heart syndrome (HLHS). Because of the abnormal physiology present in this condition, there are concerns with regard to the use of laparoscopic procedures for gastric surgery in patients treated with a three-staged reconstruction. We review the staged reconstruction of infants with HLHS, address safety concerns of interstage noncardiac procedures on this patient population, and review the current literature regarding outcomes of laparoscopic gastric surgery on patients with single ventricle physiology.

Staged palliation of hypoplastic left heart syndrome: trends in mortality, cost, and length of stay using a national database from 2000 through 2009

Staged surgical palliation has revolutionized the care of patients with hypoplastic left heart syndrome (HLHS), although the outcomes of survival and cost at a national level remain unclear. This study sought to evaluate (1) trends in HLHS surgical outcomes including in-hospital mortality, length of stay (LOS), and cost, and (2) patient and hospital risk factors associated with these outcomes. Hospitalizations for patients with HLHS, including stage I, II, and III palliations, were analyzed using the Kids' Inpatient Database from 2000 through 2009. Trends in mortality, LOS, and cost were analyzed and chi-squared tests were used to test association between categorical variables. Patient and hospital characteristics associated with death were analyzed using logistic regression and associations with LOS were analyzed using ordinary least squared regression. There were 16,923 hospital admissions in patients with HLHS of which 5,672 (34%) included surgical intervention. Total (3,201-5,102) and surgery-specific admissions (1,165-1,618) increased from 2000 to 2009. Mortality decreased 14% per year in stage III palliations (odds ratio [OR] 0.86; 95% confidence interval [CI]: 0.79-0.94) and 6% per year for stage I palliations (OR 0.94; 95% CI 0.90-0.99) but not for stage II palliations (OR 1.01; 95% CI; 0.89-1.14). Length of stay increased for stage I and II palliations; however, per-patient hospital cost decreased in 2009. In conclusion, recent decrease in per patient cost for staged surgical palliation for HLHS has correlated temporally with improved mortality.

Heart for bonding: a new protocol of care for hypoplastic left heart syndrome

There are significant challenges involved in the perinatal and postnatal care of an infant with hypoplastic left heart syndrome (HLHS) and the infant's family. In the blink of an eye, the perfect child is lost, and a fragile infant is about to join the family. This case study and discussion is an overview of HLHS , a family's desire to make the birth of their infant normal, and how that desire initiated a change in philosophy and practice in our neonatal intensive care unit.

Tricuspid valve repair in hypoplastic left heart syndrome

Tricuspid valve regurgitation (TR) remains an obstacle for staged palliation of hypoplastic left heart syndrome (HLHS). Because previous results from our institution suggested that posterior leaflet obliteration (PLO) is effective in tricuspid valve repair (TVR), we preferentially used this method. This report analyzes the effect of this preference on repair success and patient survival. All HLHS patients with 3-4+ preoperative TR undergoing TVR between 2002 and 2007 were retrospectively analyzed. Clinical and echocardiographic data were used to determine outcomes. Seventy-one percent (17 of 24) of patients had success at early outcome; the remaining 29% experienced early failure. Sixty-three percent (15 of 24) of patients demonstrated success at late outcome. Early outcome status was found to be a predictor of late outcome status (OR 22.9, P = 0.0037). Overall survival was 71% (17 of 24). Survival could not be shown to be associated with early or late outcome status (odds ratio = 0.96). A preference for PLO was found to give improved, long-lasting results for HLHS patients. Success at immediate outcome was predictive of success with time. PLO has the advantage of being simple and reproducible and produces good outcomes in this challenging group. Continued follow-up will be necessary to confirm long-term outcomes.

Heart transplantation for congenital heart disease in the first year of life

Successful infant heart transplantation has now been performed for over 25 years. Assessment of long term outcomes is now possible. We report clinical outcomes for322 patients who received their heart transplant during infancy. Actuarial graft survival for newborn recipients is 59% at 25 years. Survival has improved in the most recent era. Cardiac allograft vasculopathy is the most important late cause of death with an actuarial incidence at 25 years of 35%. Post-transplant lymphoma is estimated to occur in 20% of infant recipients by25 years. Chronic kidney disease grade 3 or worse is present in 31% of survivors. The epidemiology of infant heart transplantation has changed through the years as the results for staged repair improved and donor resources remained stagnant. Most centers now employ staged repair for hypoplastic left heart syndrome and similar extreme forms of congenital heart disease. Techniques for staged repair, including the hybrid procedure, are described. The lack of donors is described with particular note regarding decreased donors due to newer programs for appropriate infant sleep positioning and infant car seats. ABO incompatible donors are a newer resource for maximizing donor resources, as is donation after circulatory determination of death and techniques to properly utilize more donors by expanding the criteria for what is an acceptable donor. An immunological advantage for the youngest recipients has long been postulated, and evaluation of this phenomenon may provide clues to the development of accommodation and/or tolerance.