Physiologic repair of aortic atresia-hypoplastic left heart syndrome

Hybrid Interventions in Congenital Heart Disease

Hybrid interventions in congenital heart disease (CHD) embody the inherent collaboration between congenital interventional cardiology and cardiothoracic surgery. Hybrid approaches to complex and common lesions provide the opportunity to circumvent the limitations of patient size, vascular access, severity of illness, and anatomy that would otherwise be prohibitive to surgical and percutaneous techniques alone. This review describes several important hybrid approaches to interventions in CHD.

Standardization of the Norwood Procedure Improves Outcomes in a Medium-Sized Volume Center

The Norwood operation has become common practice to palliate patients with hypoplastic left heart structures. Surgical technique and postoperative care have improved; yet, there remains significant attrition prior to stage II palliation. The objective of this study is to report outcomes before and after standardizing our approach to the Norwood operation. Patients who underwent the Norwood operation at Children's of Alabama were identified, those who underwent hybrid palliation operations were excluded. Pre- (2015-2020) and post- (2020-January 2023) standardization groups were compared and outcomes analyzed. Ninety-one patients were included (pre-standardization 44 (48.3%) and 47 (51.7%) post-standardization). There were no differences in baseline and intraoperative characteristics at Norwood between the pre- and post-standardization groups. Compared with pre-standardization, post-standardization was associated with decreased time to extubation (OR 0.87, 95%CI 0.79-0.96), inotrope duration (OR 0.92, 95%CI 0.86-0.98) and hospital length of stay (OR 0.98, 95%CI 0.96-0.99). There was a trend toward decreased cardiac arrest, reintervention rates, and interstage mortality for the post-standardization group. A standardized approach to complex neonatal cardiac operations such as the Norwood procedure may improve morbidity and decrease hospital resource utilization. We recommend establishing protocols at an institutional level to optimize outcomes in such high-risk patient populations.

Surgical Management of Norwood Procedure for Atypical Aortic Arch

Background: Postoperative restenosis of the aortic arch after the Norwood procedure is still an important complication that significantly affects surgical outcomes. The rarity of the Norwood procedure for atypical aortic morphology means appropriate arch reconstruction methods and postoperative complications are still unknown. This study aimed to assess the rate of arch reintervention and clinical outcomes after the Norwood procedure for atypical aortic arch. Methods: This retrospective single-center study was conducted between 2001 and 2022. Sixteen patients were identified, eight with a right aortic arch, five with transposition of the great arteries, one with a right aortic arch and transposition of the great arteries, and two with a large tortuous patent ductus arteriosus connected to the opposite side of the descending aorta. We selected and performed four different surgical techniques depending on each aortic arch morphology. Results: Except for one case, autologous tissue-only arch reconstruction was possible. There was one operative death and four late deaths. Overall, no patients required any surgical or catheter-based reintervention for the aortic arch. On the other hand, left pulmonary artery stenosis due to a narrow subaortic space was found in two patients. Conclusions: The Norwood procedure for atypical aortic arch was performed with good results by choosing the appropriate technique for each morphology. On the other hand, pulmonary artery stenosis is likely to occur especially in the transposition of the great arteries group. Therefore, careful surgical method selection or further improvement of the technique that allows retroaortic space should be considered.

Bilateral pulmonary artery banding facilitates the systemic ventricular outflow tract growth for biventricular and univentricular repair candidates of complex arch anomaly

Various surgical approaches address complex heart disease with arch anomalies. Bilateral pulmonary artery banding (bPAB) is a strategy for critically ill patients with complex arch anomalies. Some reports argued the potential effect of bPAB on the growth of the left ventricular outflow tract (LVOT) during inter-stage after bPAB. This study aimed to analyze the LVOT growth for biventricular repair candidates with arch anomaly and systemic ventricular outflow tract (SVOT) for univentricular repair candidates with arch anomaly. This retrospective study analyzed 17 patients undergoing initial bPAB followed by arch repair. The Z-scores of LVOT and SVOT were compared between pre-bPAB and pre-arch repair. Patient characteristics, transthoracic echocardiogram data, and PAB circumferences were reviewed. The diameter of the minimum LVOT for biventricular repair (BVR) candidates, the pulmonary valve (neo-aortic valve, neo-AoV) and the pulmonary trunk (the neo-ascending aorta, neo-AAo) for univentricular repair (UVR) candidates, and the degree of aortic or neo-aortic insufficiency in each candidate was statistically analyzed. 17 patients were divided into the UVR candidates (group U) with 9 patients and the BVR candidates (group B) with 8 patients. In group B, the median value of the Z-score of the minimum LVOT increased from -3.2 (range: - 4.1 ~ - 1.0) at pre-PAB to -2.8 (range: - 3.6 ~ - 0.3) at pre-arch repair with a significant difference (p = 0.012). In group U, the median value of the Z-score of the neo-AoV increased from 0.5 (range: - 1.0 ~ 1.7) at pre-bPAB to 1.2 (range: 0.2 ~ 1.9) at pre-arch repair with a significant difference (p < 0.01). The median value of the Z-score of the neo-AAo was also increased from 3.1 (range: 1.5 ~ 4.6) to 4.3 (range: 3.1 ~ 5.9) with a significant difference (p = 0.028). The growth of the LVOT for BVR candidates and SVOT for UVR candidates during the inter-stage between bPAB and arch repair was observed. These results suggest the potential advantage of bPAB in surgical strategies. Further research is needed to validate these findings and refine surgical approaches.

Short-Term Outcomes, Functional Status, and Risk Factors for Requiring Extracorporeal Life Support After Norwood Operation: A Single-Center Retrospective Study

Patients requiring extracorporeal life support (ECLS) post-Norwood operation constitute an extremely high-risk group. We retrospectively described short-term outcomes, functional status, and assessed risk factors for requiring ECLS post-Norwood operation between January 2010 and December 2020 in a high-volume center. During the study period, 269 patients underwent a Norwood procedure of which 65 (24%) required ECLS. Of the 65 patients, 27 (41.5%) survived to hospital discharge. Mean functional status scale (FSS) score at discharge increased from 6.0 on admission to 8.48 (p < 0.0001). This change was primary in feeding (p < 0.0001) and respiratory domains (p = 0.017). Seven survivors (26%) developed new morbidity, and two (7%) developed unfavorable functional outcomes. In the regression analysis, we showed that patients with moderate-severe univentricular dysfunction on pre-Norwood transthoracic echocardiogram (odds ratio [OR] = 6.97), modified Blalock Taussig Thomas (m-BTT) shunt as source of pulmonary blood flow (OR = 2.65), moderate-severe atrioventricular valve regurgitation on transesophageal echocardiogram (OR = 8.50), longer cardiopulmonary bypass time (OR = 1.16), longer circulatory arrest time (OR = 1.20), and delayed sternal closure (OR = 3.86), had higher odds of requiring ECLS (p < 0.05). Careful identification of these risk factors is imperative to improve the care of this high-risk cohort and improve overall outcomes.

Increased utilization of the hybrid procedure is not associated with improved early survival for newborns with hypoplastic left heart syndrome: a single-centre experience

OBJECTIVES

The primary objectives were to examine utilization of the Hybrid versus the Norwood procedure for patients with hypoplastic left heart syndrome or variants and the impact on hospital mortality. The Hybrid procedure was 1st used at our institution in 2004.

METHODS

Review of all subjects undergoing the Norwood or Hybrid procedure between 1 January 1984 and 31 December 2022. The study period was divided into 8 eras: era 1, 1984-1988; era 2, 1989-1993; era 3, 1994-1998; era 4, 1999-2003; era 5, 2004-2008; era 6, 2009-2014; era 7, 2015-2018 and era 8, 2019-2022. The primary outcome was in-hospital mortality. Mortality rates were computed using standard binomial proportions with 95% confidence intervals. Rates across eras were compared using an ordered logistic regression model with and adjusted using the Tukey-Kramer post-hoc procedure for multiple comparisons. In the risk-modelling phase, logistic regression models were specified and tested.

RESULTS

The Norwood procedure was performed in 1899 subjects, and the Hybrid procedure in 82 subjects. Use of the Hybrid procedure increased in each subsequent era, reaching 30% of subjects in era 8. After adjustment for multiple risk factors, use of the Hybrid procedure was significantly and positively associated with hospital mortality.

CONCLUSIONS

Despite the increasing use of the Hybrid procedure, overall mortality for the entire cohort has plateaued. After adjustment for risk factors, use of the Hybrid procedure was significantly and positively associated with mortality compared to the Norwood procedure.

Using machine learning to predict five-year transplant-free survival among infants with hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a congenital malformation commonly treated with palliative surgery and is associated with significant morbidity and mortality. Risk stratification models have often relied upon traditional survival analyses or outcomes data failing to extend beyond infancy. Individualized prediction of transplant-free survival (TFS) employing machine learning (ML) based analyses of outcomes beyond infancy may provide further valuable insight for families and healthcare providers along the course of a staged palliation. Data from both the Pediatric Heart Network (PHN) Single Ventricle Reconstruction (SVR) trial and Extension study (SVR II), which extended cohort follow up for five years was used to develop ML-driven models predicting TFS. Models incrementally incorporated features corresponding to successive phases of care, from pre-Stage 1 palliation (S1P) through the stage 2 palliation (S2P) hospitalization. Models trained with features from Pre-S1P, S1P operation, and S1P hospitalization all demonstrated time-dependent area under the curves (td-AUC) beyond 0.70 through 5 years following S1P, with a model incorporating features through S1P hospitalization demonstrating particularly robust performance (td-AUC 0.838 (95% CI 0.836-0.840)). Machine learning may offer a clinically useful alternative means of providing individualized survival probability predictions, years following the staged surgical palliation of hypoplastic left heart syndrome.

Pediatric heart transplantation: Looking forward after five decades of learning

Heart transplantation has become the standard of care for pediatric patients with end-stage heart disease throughout the world. Since the first transplant was performed in 1967, the number of transplants has grown dramatically with 13 449 pediatric heart transplants being reported to The International Society of Heart and Lung Transplant (ISHLT) between January 1992 and June 30, 2018. Outcomes have consistently improved over the last few decades, specifically short-term outcomes. Most recent survival data demonstrate that recipients who survive to 1-year post-transplant have excellent long-term survival with more than 60% of those who were transplanted as infants being alive 25 years later. Nonetheless, the rates of graft loss beyond the first year have remained relatively constant over time; driven primarily by our poor understanding and lack of treatments for chronic allograft vasculopathy (CAV). Acute rejection, CAV, graft failure, and infection continue to be the major causes of death within the first 5 years post-transplant. In addition, renal dysfunction, malignancy, and the need for re-transplantation remain as significant issues that require close follow-up. Looking forward, key challenges include improving donor utilization rates (including donation after cardiac death (DCD) and the use of ex vivo perfusion devices), the development of non-invasive biomarkers for rejection, efforts to mitigate the long-term effects of immunosuppression, and prevention of CAV. It is not possible to cover the entire evolution of pediatric heart transplantation over the last five decades, but in this review, we hope to touch on key observations, lessons learned, and practice changes that have advanced the field, as well as glance ahead to the next decade.

Pulmonary hemodynamics before and after pediatric heart transplantation

BACKGROUND

Pulmonary hypertension (PH) may limit the outcome of pediatric heart transplantation (pHTx). We evaluated pulmonary hemodynamics in children undergoing pHTx.

METHODS

Cross-sectional, single-center, observational study analyzing pulmonary hemodynamics in children undergoing pHTx.

RESULTS

Twenty-three children (female 15) underwent pHTx at median (IQR) age of 3.9 (.9-8.2) years with a time interval between first clinical signs and pHTx of 1.1 (.4-3.2) years. Indications for pHTx included cardiomyopathy (CMP) (n = 17, 74%), congenital heart disease (CHD) (n = 5, 22%), and intracardiac tumor (n = 1, 4%). Before pHTx, pulmonary hemodynamics included elevated pulmonary artery pressure (PAP) 26 (18.5-30) mmHg, pulmonary capillary wedge pressure (PCWP) 19 (14-21) mmHg, left ventricular enddiastolic pressure (LVEDP) 17 (13-22) mmHg. Transpulmonary pressure gradient (TPG) was 6.5 (3.5-10) mmHg and pulmonary vascular resistance (Rp) 2.65 WU*m2 (1.87-3.19). After pHTx, at immediate evaluation 2 weeks after pHTx PAP decreased to 20.5 (17-24) mmHg, PCWP 14.5 (10.5-18) mmHg (p < .05), LVEDP 16 (12.5-18) mmHg, TPG 6.5 (4-12) mmHg, Rp 1.49 (1.08-2.74) WU*m2 resp.at last invasive follow up 4.0 (1.4-6) years after pHTx, to PAP 19.5 (17-21) mmHg (p < .05), PCWP 13 (10.5-14.5) mmHg (p < .05), LVEDP 13 (10.5-14) mmHg, TPG 7 (5-9.5) mmHg, Rp 1.58 (1.38-2.19) WU*m2 (p < .05). In CHD patients PAP increased (p < .05) after pHTx at immediate evaluation and decreased until last follow-up (p < .05), while in CMP patients there was a continuous decline of mean PAP values immediately after HTx (p < .05).

CONCLUSIONS

While PH before pHTx is frequent, after pHTx the normalization of PH starts immediately in CMP patients but is delayed in CHD patients.

From Surgical to Total Transcatheter Stage I Palliation: Exploring Evidence and Perspectives

Neonates with single ventricle physiology and ductal-dependent systemic circulation, such as those with hypoplastic left heart syndrome, undergo palliation in the first days of life. Over the past decades, variations on the traditional Stage 1 palliation, also known as Norwood operation, have emerged. These include the hybrid palliation and the total transcatheter approach. Here, we review the current evidence and data on different Stage 1 approaches, with a focus on their advantages, challenges, and future perspectives. Overall, although controversy remains regarding the superiority or inferiority of one approach to another, outcomes after the Norwood and the hybrid palliation have improved over time. However, both procedures still represent high-risk approaches that entail exposure to sternotomy, surgery, and potential cardiopulmonary bypass. The total transcatheter Stage 1 palliation spares patients the surgical and cardiopulmonary bypass insults and has proven to be an effective strategy to bridge even high-risk infants to a later palliative surgery, complete repair, or transplant. As the most recently proposed approach, data are still limited but promising. Future studies will be needed to better define the advantages, challenges, outcomes, and overall potential of this novel approach.

Fetal single ventricle journey to first postnatal procedure: a multicentre UK cohort study

OBJECTIVES

UK single ventricle (SV) palliation outcomes after first postnatal procedure (FPP) are well documented. However, survival determinants from fetal diagnosis to FPP are lacking. To better inform parental-fetal counselling, we examined factors favouring survival at two large UK centres.

DESIGN

Retrospective multicentre cohort study.

SETTING

Two UK congenital cardiac centres: Leeds and Birmingham.

PATIENTS

SV fetal diagnoses from 2015 to 2021.

MAIN OUTCOME MEASURES

Survival from fetal diagnosis with intention to treat (ITT) to birth and then FPP. Maternal, fetal and neonatal risk factors were assessed.

RESULTS

There were 666 fetal SV diagnoses with 414 (62%) ITT. Of ITT, 381 (92%) were live births and 337 (81%) underwent FPP. Survival (ITT) to FPP was notably reduced for severe Ebstein's 14/22 (63.6%), unbalanced atrioventricular septal defect 32/45 (71%), indeterminate SV 3/4 (75%), mitral atresia 8/10 (80%) and hypoplastic left heart syndrome 127/156 (81.4%). Biventricular pathway was undertaken in five (1%). After multivariable adjustment, prenatal risk factors for mortality were increasing maternal age (OR 1.05, 95% CI 1.0 to 1.1), non-white ethnicity (OR 2.6, 95% CI 1.4 to 4.8), extracardiac anomaly (OR 6.34, 95% CI 1.8 to 22.7) and hydrops (OR 7.39, 95% CI 1.2 to 45.1). Postnatally, prematurity was significantly associated with mortality (OR 6.3, 95% CI 2.3 to 16.8).

CONCLUSIONS

Around 20% of ITT fetuses diagnosed with SV will not reach FPP. Risk varies according to the cardiac lesion and is significantly influenced by the presence of an extracardiac anomaly, fetal hydrops, ethnicity, increasing maternal age and gestation at birth. These data highlight the need for fetal preprocedure data to be used in conjunction with procedural outcomes for fetal counselling.

Association Between Remote Monitoring and Interstage Morbidity and Death in Patients With Single-Ventricle Heart Disease Across Socioeconomic Groups

BACKGROUND

Despite improvements in survival over time, the mortality rate for infants with single-ventricle heart disease remains high. Infants of low socioeconomic status (SES) are particularly vulnerable. We sought to determine whether use of a novel remote monitoring program, the Cardiac High Acuity Monitoring Program, mitigates differences in outcomes by SES.

METHODS AND RESULTS

Within the Cardiac High Acuity Monitoring Program, we identified 610 infants across 11 centers from 2014 to 2021. All enrolled families had access to a mobile application allowing for near-instantaneous transfer of patient information to the care team. Patients were divided into SES tertiles on the basis of 6 variables relating to SES. Hierarchical logistic regression, adjusted for potential confounding characteristics, was used to determine the association between SES and death or transplant listing during the interstage period. Of 610 infants, 39 (6.4%) died or were listed for transplant. In unadjusted analysis, the rate of reaching the primary outcome between SES tertiles was similar (P=0.24). Even after multivariable adjustment, the odds of death or transplant listing were no different for those in the middle (odds ratio, 1.7 [95% CI, 0.73-3.94) or highest (odds ratio, 0.997 [95% CI, 0.30, 3.36]) SES tertile compared with patients in the lowest (overall P value 0.4).

CONCLUSIONS

In a large multicenter cohort of infants with single-ventricle heart disease enrolled in a digital remote monitoring program during the interstage period, we found no difference in outcomes based on SES. Our study suggests that this novel technology could help mitigate differences in outcomes for this fragile population of patients.

Markov model for detection of ECG instability prior to cardiac arrest in single-ventricle patients

OBJECTIVES

Assess the degree of instability in the electrocardiogram (ECG) waveform in patients with single-ventricle physiology before a cardiac arrest and compare them with similar patients who did not experience a cardiac arrest.

METHODS

Retrospective control study in patients with single-ventricle physiology who underwent Norwood, Blalock-Taussig shunt, pulmonary artery band, and aortic arch repair from 2013 to 2018. Electronic medical records were obtained for all included patients. For each subject, 6 h of ECG data were analyzed. In the arrest group, the end of the sixth hour coincides with the cardiac arrest. In the control group, the 6-h windows were randomly selected. We used a Markov chain framework and the likelihood ratio test to measure the degree of ECG instability and to classify the arrest and control groups.

RESULTS

The study dataset consists of 38 cardiac arrest events and 67 control events. Our Markov model was able to classify the arrest and control groups based on the ECG instability with an ROC AUC of 82% at the hour preceding the cardiac arrests.

CONCLUSION

We designed a method using the Markov chain framework to measure the level of instability in the beat-to-beat ECG morphology. Furthermore, we were able to show that the Markov model performed well to distinguish patients in the arrest group compared to the control group.

Milrinone for treatment of elevated lactate in the pre-operative newborn with hypoplastic left heart syndrome

BACKGROUND

There is a paucity of information reported regarding the use of milrinone in patients with hypoplastic left heart syndrome prior to the Norwood procedure. At our institution, milrinone is initiated in the pre-operative setting when over-circulation and elevated serum lactate levels develop. We aimed to review the responses associated with the administration of milrinone in the pre-operative hypoplastic left heart syndrome patient. Second, we compared patients who received high- versus low-dose milrinone prior to Norwood procedure.

METHODS

Single-centre retrospective study of patients diagnosed with hypoplastic left heart syndrome between January 2000 and December 2019 who underwent Norwood procedure. Patient characteristics and outcomes were compared.

RESULTS

During the study period, 375 patients were identified; 79 (21%) received milrinone prior to the Norwood procedure with median lactate 2.55 mmol/l, and SpO2 93%. Patients who received milrinone were older at the time of Norwood procedure (6 vs. 5 days) and were more likely to be intubated and sedated. In a subset analysis stratifying patients to low- versus high-dose milrinone, median lactate decreased from time of initiation (2.39 vs 2.75 to 1.6 vs 1.8 mmol/l) at 12 hours post-initiation, respectively. Repeated measures analysis showed a significant decrease in lactate levels by 4 hours following initiation of milrinone, that persisted over time, with no significant difference in mean arterial pressure.

CONCLUSIONS

The use of milrinone in the pre-operative over-circulated hypoplastic left heart syndrome patient is well tolerated, is associated with decreased lactate levels, and was not associated with significant hypotension or worsening of excess pulmonary blood flow.

Historical Accounts of Congenital Heart Surgery

We present historical accounts of congenital heart surgery since the early 1900s, as our specialty evolved from individual heroic efforts into an established and sophisticated surgical specialty with consistent and excellent results. We highlight colleagues and intrepid pioneers who have strived to solve seemingly insurmountable problems during this remarkable journey and celebrate continued success into the 21st century with surgical advances that have resulted in innovative operations, database inquiries, quality measures, new techniques of medical illustration, and the establishment of the Congenital Heart Surgeons' Society, which has become the leading organization dedicated to congenital heart surgery in North America.

New approach in stage 1 surgery for hypoplastic left heart syndrome: preliminary outcomes

OBJECTIVES

We present the short-term results of an alternative method in stage 1 surgery for hypoplastic left heart syndrome.

METHODS

Data of 16 consecutive patients who were treated with the novel method in our clinic between February 2019 and March 2021 were analysed retrospectively. Preoperative data and postoperative follow-up were recorded.

RESULTS

Of the 16 operated patients, 12 were diagnosed with hypoplastic left heart syndrome, while four were diagnosed with hypoplastic left heart syndrome variants. Seven patients died during early postoperative period. One patient died at home waiting stage 2 surgery. Three patient underwent stage 2 surgery. Pulmonary artery reconstruction was performed in one patient due to left pulmonary artery distortion.

CONCLUSIONS

We believe that our method can be an effective alternative in the surgery of hypoplastic left heart syndrome and its variants. It is hoped that with increasing number of studies and more experience better outcome will be achieved.

Utilizing technology to expand home monitoring to high-risk infants with CHD

Infants born with single ventricle physiology that require an aorto-pulmonary shunt are at high risk for sudden cardiac death, particularly during the interstage period between the first-stage palliation and the second-stage palliation. Home monitoring programs have decreased interstage mortality in the hypoplastic left heart syndrome population prompting programs to expand the home monitoring program to other high-risk populations. At our mid-sized program, we implemented the Locus Health home monitoring platform first in the hypoplastic left heart syndrome population, then expanding to the single ventricle shunt population. Interstage mortality for the hypoplastic left heart syndrome population after initiation of the home monitoring program went from 18% prior to 2009 to 7% as of the end of 2020 (n = 99), with 2.8% mortality from 2013 to 2020 and 0% mortality since initiation of the Locus program in 2017. Caregiver surveys done prior to discharge and then 3 weeks later were used to document caregiver experience using the digital home monitoring program. Caregivers reported overall positive experience with the digital application, with 91.8% stating that they felt confident taking care of their baby at home. Transitioning the home monitoring program from a traditional binder to an iPad with the Locus Health application allowed us to expand the program, utilize the electronic medical record, bill for the service, and demonstrate positive experiences for caregivers. Overall engagement and adherence with the program by caregivers were 50.94 and 45.45%, with a total of 112 patient episodes. Reimbursement from private insurance providers was 22% of the billed amount for 2020.

The application of simultaneous mainstem bronchus dilation with pulmonary artery stenting in the context of hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a congenital diagnosis that necessitates immediate intervention at the beginning of life to ensure survival past infancy and to optimize left-side cardiac function. Often, these required procedures can lead to deleterious side effects and resultant complications. In this case report, we present a 15-month-old patient with HLHS who underwent multiple procedures, including two aortic arch surgeries. After the interventions, the patient experienced left main pulmonary bronchus compression along with pulmonary artery stenosis. In this case, we outline an approach to performing vascular dilation without compromise of airway patency.

Hypoplastic Left Heart Syndrome: A Review

Hypoplastic left heart syndrome is a rare and poorly understood congenital disorder featuring a univentricular myocardium, invariably resulting in early childhood death if left untreated. The process to palliate this congenital cardiomyopathy is of high complexity and may include invasive interventions in the first week of life. The preferred treatment strategy involves a staged correction with 3 surgical procedures at different points in time. The Norwood procedure is usually performed within the first weeks of life and aims to increase systemic circulation and relieve pulmonary vascular pressure. This procedure is followed by the bidirectional Glenn and the Fontan procedures in later life, which offer to decrease stress in the ventricular chamber. The prognosis of children with this disease has greatly improved in the past decades; however, it is still largely driven by multiple modifiable and nonmodifiable variables. Novel and clever alternatives have been proposed to improve the survival and neurodevelopment of these patients, although they are not used as standard of care in all centers. The neurodevelopmental outcomes among these patients have received particular attention in the last decade in light to improve this very limiting associated comorbidity that compromises quality of life.

Factors influencing the choice-of-care pathway and survival in the fetus with hypoplastic left heart syndrome in New Zealand: a population-based cohort study

OBJECTIVES

To better understand the relative influence of fetal and maternal factors in determining the choice-of-care pathway (CCP) and outcome in the fetus with hypoplastic left heart syndrome (HLHS).

DESIGN

A retrospective, population-based study of fetuses with HLHS from a national dataset with near-complete case ascertainment from 20 weeks' gestation. Fetal cardiac and non-cardiac factors were recorded from the patient record and maternal factors from the national maternity dataset. The primary endpoint was a prenatal decision for active treatment after birth (intention-to-treat). Factors associated with a delayed diagnosis (≥24 weeks' gestation) were also reviewed. Secondary endpoints included proceeding to surgical treatment, and 30-day postoperative mortality in liveborns with an intention-to-treat.

SETTING

New Zealand population-wide.

PARTICIPANTS

Fetuses with a prenatal diagnosis of HLHS between 2006 and 2015.

RESULTS

Of 105 fetuses, the CCP was intention-to-treat in 43 (41%), and pregnancy termination or comfort care in 62 (59%). Factors associated with intention-to-treat by multivariable analysis included a delay in diagnosis (OR: 7.8, 95% CI: 3.0 to 20.6, p<0.001) and domicile in the maternal fetal medicine (MFM) region with the most widely dispersed population (OR: 5.3, 95% CI: 1.4 to 20.3, p=0.02). Delay in diagnosis was associated with Māori maternal ethnicity compared with European (OR: 12.9, 95% CI: 3.1 to 54, p<0.001) and greater distance from the MFM centre (OR: 3.1, 95% CI: 1.2 to 8.2, p=0.02). In those with a prenatal intention-to-treat, a decision not to proceed to surgery was associated with maternal ethnicity other than European (p=0.005) and the presence of major non-cardiac anomalies (p=0.01). Thirty-day postoperative mortality occurred in 5/32 (16%) and was more frequent when there were major non-cardiac anomalies (p=0.02).

CONCLUSIONS

Factors associated with the prenatal CCP relate to healthcare access. Anatomic characteristics impact treatment decisions after birth and early postoperative mortality. The association of ethnicity with delayed prenatal diagnosis and postnatal decision-making suggests systemic inequity and requires further investigation.

What Is the Hypoplastic Left Heart Syndrome?

As yet, there is no agreed definition for the so-called "hypoplastic left heart syndrome". Even its origin remains contentious. Noonan and Nadas, who as far as we can establish first grouped together patients as belonging to a "syndrome" in 1958, suggested that Lev had named the entity. Lev, however, when writing in 1952, had described "hypoplasia of the aortic outflow tract complex". In his initial description, as with Noonan and Nadas, he included cases with ventricular septal defects. In a subsequent account, he suggested that only those with an intact ventricular septum be included within the syndrome. There is much to commend this later approach. When assessed on the basis of the integrity of the ventricular septum, the hearts to be included can be interpreted as showing an acquired disease of fetal life. Recognition of this fact is important to those seeking to establish the genetic background of left ventricular hypoplasia. Flow is also of importance, with septal integrity then influencing its effect on the structure of the hypoplastic ventricle. In our review, we summarise the evidence supporting the notion that an intact ventricular septum should now be part of the definition of the hypoplastic left heart syndrome.

Normothermic Versus Hypothermic Norwood Procedure

BACKGROUND

Either deep hypothermia with circulatory arrest or hypothermic perfusion with antegrade selective cerebral perfusion is used during the Norwood procedure for hypoplastic left heart syndrome. Normothermic perfusion has been described for pediatric patients. The aim of this study was to compare the early outcomes of patients undergoing the Norwood procedure with antegrade selective cerebral perfusion under hypothermia with the procedure under normothermia.

METHODS

From 2005 to 2020, 117 consecutive patients with hypoplastic left heart syndrome underwent the Norwood procedure: 68 (58.2%) under hypothermia and 49 (41.8%) under normothermia. Antegrade selective cerebral perfusion flow was adjusted to maintain right radial arterial pressure above 50 mm Hg, and a flow rate of 40 to 50 mL kg^-1 min^-1. Baseline characteristics, operative data, and postoperative outcomes including lactate recovery time were compared.

RESULTS

The baseline characteristics and cardiovascular diagnosis were similar in both groups. The normothermic group had a significantly shorter bypass time (in minutes) of 90.31 (±31.60) versus 123.63 (±25.33), a cross-clamp time of 45.24 (±16.35) versus 81.93 (±16.34), and an antegrade selective cerebral perfusion time of 25.61 (±13.84) versus 47.30 (±14.35) (P < .001). There were no statistically significant differences in the immediate postoperative course, or in terms of in-hospital mortality, which totaled 9 (18.4%) in the normothermic group, and 10 (14.9%) in the hypothermic group (P = .81).

CONCLUSION

The normothermic Norwood procedure with selective cerebral perfusion is feasible and safe in terms of in-hospital mortality and short-term outcomes. It is comparable to the standard hypothermic Norwood with selective cerebral perfusion.

Minimally Invasive Fetal Surgery and the Next Frontier

Most patients with congenital anomalies do not require prenatal intervention. Furthermore, many congenital anomalies requiring surgical intervention are treated adequately after birth. However, there is a subset of patients with congenital anomalies who will die before birth, shortly after birth, or experience severe postnatal complications without fetal surgery. Fetal surgery is unique in that an operation is performed on the fetus as well as the pregnant woman who does not receive any direct benefit from the surgery but rather lends herself to risks, such as hemorrhage, abruption, and preterm labor. The maternal risks involved with fetal surgery have limited the extent to which fetal interventions may be performed but have, in turn, led to technical innovations that have significantly advanced the field. This review will examine congenital abnormalities that can be treated with minimally invasive fetal surgery and introduce the next frontier of prenatal management of fetal surgical pathology.

The tricuspid valve in hypoplastic left heart syndrome: Echocardiography provides insight into anatomy and function

Tricuspid regurgitation (TR) is commonly seen in surgically palliated patients with hypoplastic left heart syndrome, and when significant, is associated with an increase in both morbidity and mortality. Tricuspid valve dysfunction appears to be the result of a combination of inherent structural malformations and the unique physiological circumstances resulting from right ventricular pressure and volume overload. Valve dysfunction evolves rapidly, and manifests early on in the surgical pathway. Whilst traditional echocardiographic imaging can identify anatomical defects and dysfunction resulting in varying degrees of regurgitation even at early stages, more sophisticated investigations such as 3D echocardiography, strain imaging and transesophageal 3DE might prove useful to better demonstrate the complex interactions between abnormal anatomy of the valve complex, ventricular function, mechanical synchrony, and TR. Recognition of specific mechanisms of TR can enhance patient-specific care by directing precise surgical interventions and by informing the best timing for intervention on the valve.

Current state of the art in hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a complex congenital heart condition in which a neonate is born with an underdeveloped left ventricle and associated structures. Without palliative interventions, HLHS is fatal. Treatment typically includes medical management at the time of birth to maintain patency of the ductus arteriosus, followed by three palliative procedures: most commonly the Norwood procedure, bidirectional cavopulmonary shunt, and Fontan procedures. With recent advances in surgical management of HLHS patients, high survival rates are now obtained at tertiary treatment centers, though adverse neurodevelopmental outcomes remain a clinical challenge. While surgical management remains the standard of care for HLHS patients, innovative treatment strategies continue to be developing. Important for the development of new strategies for HLHS patients is an understanding of the genetic basis of this condition. Another investigational strategy being developed for HLHS patients is the injection of stem cells within the myocardium of the right ventricle. Recent innovations in tissue engineering and regenerative medicine promise to provide important tools to both understand the underlying basis of HLHS as well as provide new therapeutic strategies. In this review article, we provide an overview of HLHS, starting with a historical description and progressing through a discussion of the genetics, surgical management, post-surgical outcomes, stem cell therapy, hemodynamics and tissue engineering approaches.

Perioperative Management of a Child with Hypoplastic Left Heart Syndrome Undergoing Cryptorchidism Surgery

Hypoplastic left heart syndrome (HLHS) is a complex congenital heart condition which includes abnormal development of left sided cardiac structures leading to inadequate systemic perfusion following postnatal closure of the patent ductus arteriosus (PDA). Surgical palliation may be accomplished through a 3 staged process -Norwood procedure. This surgery is usually done within the first two weeks of your child's life -Bidirectional Glenn procedure. This procedure is generally the second surgery. It's done when your child is between 3 and 6 months of age. -Fontan procedure. This surgery is usually done when your child is between 18 months and 4 years of age. Patients with HLHS may need to undergo other non-cardiac surgical procedures during the first years of life posing a real challenge to the anesthesiologist, surgeon and the entire medical team. We present the case of a 18-months old, 9 kg infant who presented for cryptorchidism surgery. Cryptorchidism or undescended testis (UDT) is one of the most common pediatric disorders of the male endocrine glands and the most common genital disorder identified at birth. The main reasons for treatment of cryptorchidism include increased risks of impairment of fertility potential, testicular malignancy, torsion and/or associated inguinal hernia. The intraoperative implications of the hybrid anatomy are discussed, options for anesthetic care presented, and previous reports of anesthetic care for such patients reviewed. Conclusion: LMA combined with local anesthesia was effective to maintaining optimal cardiac function of this child patient with HLHS In summary, children with palliated HLHS have anesthetic considerations that must be followed in order to reduce perioperative morbidity and mortality in this high-risk pathology.

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.

Technical Aspects and Common Pitfalls of Norwood With Modified Blalock Taussig Shunt

The Stage 1 Norwood procedure is the first of 3 stages in the surgical palliation of hypoplastic left heart syndrome and certain other single ventricle lesions with systemic outflow obstruction. In this article, we address some technical aspects and common pitfalls of the Norwood procedure with systemic to pulmonary shunt for HLHS palliation. We report our results with the Norwood with Blalock Taussig shunt in a cohort of 44 patients over a 7-year period in 2 institutions in Argentina. The results of the Norwood procedure have improved significantly through the understanding and refinement of the surgical techniques. Procedures must be technically perfect since residual lesions are poorly tolerated. Norwood with a modified Blalock Taussig shunt can be performed with low mortality and may provide excellent long-term outcomes.

Mitral Atresia with Normal Aortic Root

Mitral atresia with normal aortic root is a rare complex congenital heart defect (CHD) and constitute less than 1% of all CHDs. In this anomaly, the mitral valve is atretic, a patent foramen ovale provides egress of the left atrial blood, either a single ventricle or two ventricles with left ventricular hypoplasia are present, and the aortic valve/root are normal by definition. Clinical, roentgenographic and electrocardiographic features are non-distinctive, but echo-Doppler studies are useful in defining the anatomic and pathophysiologic components of this anomaly with rare need for other imaging studies. Treatment consists of addressing the pathophysiology resulting from defect and associated cardiac anomalies at the time of initial presentation, usually in the early infancy. These children eventually require staged total cavo-pulmonary connection (Fontan) in three stages. Discussion of each of these stages were presented. Complications are observed in-between the stages of Fontan surgery and following completion of Fontan procedure. Attempts to monitor for early detection of these complications and promptly addressing the complications are recommended.

Pioneers in congenital cardiac surgery: Dr. William Imon Norwood, Jr, MD, PhD

"Innovation is not only the fountainhead but the life's blood of our specialty, of surgery, of medicine, of business, or of just about anything that is progressing, evolving, and improving. In the absence of innovation there is stagnation and ultimately there is decay. Cardiac surgery, particularly congenital cardiac surgery, must continue to evolve through innovation."

Society for Cardiovascular Magnetic Resonance/European Society of Cardiovascular Imaging/American Society of Echocardiography/Society for Pediatric Radiology/North American Society for Cardiovascular Imaging Guidelines for the use of cardiovascular magnetic resonance in pediatric congenital and acquired heart disease : Endorsed by The American Heart Association

Cardiovascular magnetic resonance (CMR) has been utilized in the management and care of pediatric patients for nearly 40 years. It has evolved to become an invaluable tool in the assessment of the littlest of hearts for diagnosis, pre-interventional management and follow-up care. Although mentioned in a number of consensus and guidelines documents, an up-to-date, large, stand-alone guidance work for the use of CMR in pediatric congenital 36 and acquired 35 heart disease endorsed by numerous Societies involved in the care of these children is lacking. This guidelines document outlines the use of CMR in this patient population for a significant number of heart lesions in this age group and although admittedly, is not an exhaustive treatment, it does deal with an expansive list of many common clinical issues encountered in daily practice.

Society for Cardiovascular Magnetic Resonance/European Society of Cardiovascular Imaging/American Society of Echocardiography/Society for Pediatric Radiology/North American Society for Cardiovascular Imaging Guidelines for the Use of Cardiac Magnetic Resonance in Pediatric Congenital and Acquired Heart Disease: Endorsed by The American Heart Association

Cardiovascular magnetic resonance has been utilized in the management and care of pediatric patients for nearly 40 years. It has evolved to become an invaluable tool in the assessment of the littlest of hearts for diagnosis, pre-interventional management and follow-up care. Although mentioned in a number of consensus and guidelines documents, an up-to-date, large, stand-alone guidance work for the use of cardiovascular magnetic resonance in pediatric congenital 36 and acquired 35 heart disease endorsed by numerous Societies involved in the care of these children is lacking. This guidelines document outlines the use of cardiovascular magnetic resonance in this patient population for a significant number of heart lesions in this age group and although admittedly, is not an exhaustive treatment, it does deal with an expansive list of many common clinical issues encountered in daily practice.

Performance of a single-ventricle home-monitoring programme: survival and predictors of adverse outcome

INTRODUCTION AND BACKGROUND

Mortality between stages 1 and 2 single-ventricle palliation is significant. Home-monitoring programmes are suggested to reduce mortality. Outcomes and risk factors for adverse outcomes for European programmes have not been published.

AIMS

To evaluate the performance of a home-monitoring programme at a medium-sized United Kingdom centre with regards survival and compare performance with other home-monitoring programmes in the literature.

METHODS

All fetal and postnatal diagnosis of a single ventricle were investigated with in-depth analysis of those undergoing stage 1 palliation and entered the home-monitoring programme between 2016 and 2020. The primary outcome was survival. Secondary outcomes included multiple parameters as potential predictors of death or adverse outcome.

RESULTS

Of 217 fetal single-ventricle diagnoses during the period 2016-2020, 50.2% progressed to live birth, 35.4% to stage 1 and 29.5% to stage 2. Seventy-four patients (including 10 with postnatal diagnosis) entered the home-monitoring programme with six deaths making home-monitoring programme mortality 8.1%. Risk factors for death were the hybrid procedure as the only primary procedure (OR 33.0, p < 0.01), impaired cardiac function (OR 10.3, p < 0.025), Asian ethnicity (OR 9.3, p < 0.025), lower mean birth-weight (2.69 kg versus 3.31 kg, p < 0.01), and lower mean weight centiles during interstage follow-up (mean centiles of 3.1 versus 10.8, p < 0.01).

CONCLUSION

Survival in the home-monitoring programme is comparable with other home-monitoring programmes in the literature. Hybrid procedure, cardiac dysfunction, sub-optimal weight gain, and Asian ethnicity were significant risk factors for death. Home-monitoring programmes should continue to raise awareness of these factors and seek solutions to mitigate adverse events. Future work to generalise home-monitoring programme and single-ventricle fetus to stage 2 outcomes in the United Kingdom will require multi-centre collaboration.

Hypoplastic Left Heart Syndrome Across the Lifespan: Clinical Considerations for Care of the Fetus, Child, and Adult

Hypoplastic left heart syndrome (HLHS) is the most common anatomic lesion in children born with single ventricle physiology and is characterized by the presence of a dominant right ventricle and a hypoplastic left ventricle along with small left-sided heart structures. Diagnostic subgroups of HLHS reflect the extent of inflow and outflow obstruction at the aortic and mitral valves, specifically stenosis or atresia. If left unpalliated, HLHS is a uniformly fatal lesion in infancy. Following introduction of the Norwood operation, early survival has steadily improved over the past four decades, mirroring advances in operative and peri-operative management as well as reflecting refinements in patient surveillance and interstage clinical care. Notably, survival following staged palliation has increased from 0% to a 5-year survival of 60-65% for children in some centres. Despite the prevalence of HLHS in childhood with relatively favourable surgical outcomes in contemporary series, this cohort is only now reaching early adult life and longer-term outcomes have yet to be elucidated. In this article we focus on contemporary clinical management strategies for patients with HLHS across the lifespan, from fetal to adult life. Nomenclature and diagnostic considerations are discussed and current literature pertaining to putative genetic etiologies is reviewed. The spectrum of fetal and pediatric interventional strategies, both percutaneous and surgical, are described. Clinical, patient-reported and neurodevelopmental outcomes of HLHS are delineated. Finally, note is made of current areas of clinical uncertainty and suggested directions for future research are highlighted.

A Comprehensive Approach to the Management of Patients With HLHS and Related Malformations: An Analysis of 83 Patients (2015-2021)

Background: Some patients with hypoplastic left heart syndrome (HLHS) and HLHS-related malformations with ductal-dependent systemic circulation are extremely high-risk for Norwood palliation. We report our comprehensive approach to the management of these patients designed to maximize survival and optimize the utilization of donor hearts. Methods: We reviewed our entire current single center experience with 83 neonates and infants with HLHS and HLHS-related malformations (2015-2021). Standard-risk patients (n = 62) underwent initial Norwood (Stage 1) palliation. High-risk patients with risk factors other than major cardiac risk factors (n = 9) underwent initial Hybrid Stage 1 palliation, consisting of application of bilateral pulmonary bands, stent placement in the patent arterial duct, and atrial septectomy if needed. High-risk patients with major cardiac risk factors (n = 9) were bridged to transplantation with initial combined Hybrid Stage 1 palliation and pulsatile ventricular assist device (VAD) insertion (HYBRID + VAD). Three patients were bridged to transplantation with prostaglandin. Results: Overall survival at 1 year = 90.4% (75/83). Operative Mortality for standard-risk patients undergoing initial Norwood (Stage 1) Operation was 2/62 (3.2%). Of 60 survivors: 57 underwent Glenn, 2 underwent biventricular repair, and 1 underwent cardiac transplantation. Operative Mortality for high-risk patients with risk factors other than major cardiac risk factors undergoing initial Hybrid Stage 1 palliation without VAD was 0/9: 4 underwent transplantation, 1 awaits transplantation, 3 underwent Comprehensive Stage 2 (with 1 death), and 1 underwent biventricular repair. Of 9 HYBRID + VAD patients, 6 (67%) underwent successful cardiac transplantation and are alive today and 3 (33%) died while awaiting transplantation on VAD. Median length of VAD support was 134 days (mean = 134, range = 56-226). Conclusion: A comprehensive approach to the management of patients with HLHS or HLHS-related malformations is associated with Operative Mortality after Norwood of 2/62 = 3.2% and a one-year survival of 75/83 = 90.4%. A subset of 9/83 patients (11%) were stabilized with HYBRID + VAD while awaiting transplantation. VAD facilitates survival on the waiting list during prolonged wait times.

Tissue engineering: Relevance to neonatal congenital heart disease

Congenital heart disease (CHD) represents a large clinical burden, representing the most common cause of birth defect-related death in the newborn. The mainstay of treatment for CHD remains palliative surgery using prosthetic vascular grafts and valves. These devices have limited effectiveness in pediatric patients due to thrombosis, infection, limited endothelialization, and a lack of growth potential. Tissue engineering has shown promise in providing new solutions for pediatric CHD patients through the development of tissue engineered vascular grafts, heart patches, and heart valves. In this review, we examine the current surgical treatments for congenital heart disease and the research being conducted to create tissue engineered products for these patients. While much research remains to be done before tissue engineering becomes a mainstay of clinical treatment for CHD patients, developments have been progressing rapidly towards translation of tissue engineering devices to the clinic.

Outcomes of Norwood procedure with hypoplastic left heart syndrome: Our 12-year single-center experience

Background

In this study, we aimed to analyze the predictors and risk factors of mortality in patients who underwent Norwood I procedure with the diagnosis of hypoplastic left heart syndrome.

Methods

Between January 2009 and December 2020, a total of 139 patients (95 males, 44 females) who underwent Norwood I procedure with the diagnosis of hypoplastic left heart syndrome in our center were retrospectively analyzed.

Results

The median birth weight was 3,200 (range, 3,000 to 3,350) g and the median age at the time of operation was seven (range, 5 to 10) days. Pulmonary flow was achieved with a Sano shunt in the majority (72%) of patients. Survival rate was 41% after the first stage. Reoperation for bleeding (p=0.017), reoperation for residual lesion (p=0.011), and postoperative peak lactate level (p=0.029), were associated with in-hospital mortality. Nineteen (33%) of 57 patients died before the second stage. Thirty-three (58%) patients underwent second stage, and survival after the second stage was 94%. Thirteen patients underwent third stage, and survival after the third stage was 85%. Estimated probability of survival at six months, and one, two, three, and four years were 33%, 33%, 25%, 25%, and 22% respectively.

Conclusion

Hospital and inter-stage mortality rates are still high and this seems to be the most challenging period in term of survival efforts of the patients with hypoplastic left heart syndrome. Early recognition and reintervention of anatomical residual defects, close follow-up in the inter-stage period, and the accumulation of multidisciplinary experience may help to improve the results to acceptable limits.

Cardiac Interventions for Patients With Trisomy 13 and Trisomy 18: Experience, Ethical Issues, Communication, and the Case for Individualized Family-Centered Care

This report is informed by the themes of the session Trisomy 13/18, Exploring the Changing Landscape of Interventions at NeoHeart 2020-The Fifth International Conference of the Neonatal Heart Society. The faculty reviewed the present evidence in the management of patients and the support of families in the setting of trisomy 13 and trisomy 18 with congenital heart disease. Until recently medical professionals were taught that T13 and 18 were "lethal conditions" that were "incompatible with life" for which measures to prolong life are therefore ethically questionable and likely futile. While the medical literature painted one picture, family support groups shared stories of the long-term survival of children who displayed happiness and brought joy along with challenges to families. Data generated from such care shows that surgery can, in some cases, prolong survival and increase the likelihood of time at home. The authors caution against a change from never performing heart surgery to always-we suggest that the pendulum of intervention find a balanced position where all therapies including comfort care and surgery can be reviewed. Families and clinicians should typically be supported and empowered to define the best care for their children and patients. Key concepts in communication and case vignettes are reviewed including the importance of supportive relationships and the fact that palliative care may serve as an additional layer of support for decision-making and quality of life interventions. While cardiac surgery may be beneficial in some cases, surgery should not be the primary focus of initial family education and support.

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

BACKGROUND

The Norwood procedure is the first stage of correction for patients with hypoplastic left heart syndrome (HLHS) and may lead to an abnormal neoaortic anatomy. We prospectively studied the neoaorta's fluid dynamics and the abnormal twist of the neoaorta by MRI examinations of HLHS patients in Fontan circulation. This study for the first time investigates the hypothesis that the neoaorta twist is associated with increased helical flow patterns, which may lead to an increased workload for the systemic right ventricle (RV) and ultimately to RV hypertrophy.

METHODS

A group of forty-two HLHS patients with a median age of 4.9 (2.9-17.0) years, at NYHA I was studied along with a control group of eleven subjects with healthy hearts and a median age of 12.1 (4.0-41.6). All subjects underwent MRI of the thoracic aorta including ECG-gated 2D balanced SSFP cine for an axial slice stack and 4D-flow MRI for a sagittal volume slab covering the thoracic aorta. The twist of the neoaortic arch was quantified by the effective geometric torsion, defined as the product of curvature and geometric torsion. Fluid dynamics and geometry in the neoaorta, including the flow helicity index, were evaluated using an in-house analysis software (MeVisLab-based). Myocardial mass of the systemic ventricle at end-diastole was estimated by planimetry of the short-axis stack.

RESULTS

Compared to the control group, the neoaorta in the HLHS patients shows an increased twist (P=0.04) and higher peak helicity density (P=0.03). The maximum helicity density was correlated with maximum effective torsion of the ascending neoaorta (P<0.001). The degree of maximum twist correlated with the increase in RV myocardial mass (P<0.01).

CONCLUSIONS

This study shows that the abnormal twist of the neoaortic arch in HLHS patients is associated with abnormal helical flow patterns, which may contribute to increased RV afterload and may adversely affect the systemic RV by stimulation of myocardial hypertrophy. These findings suggest that further improvements of surgical aortic reconstruction, guided by insights from 4D-flow MRI, could lead to better neoaortic fluid dynamics in patients with HLHS.

Health Care Policy and Congenital Heart Disease: 2020 Focus on Our 2030 Future

The congenital heart care community faces a myriad of public health issues that act as barriers toward optimum patient outcomes. In this article, we attempt to define advocacy and policy initiatives meant to spotlight and potentially address these challenges. Issues are organized into the following 3 key facets of our community: patient population, health care delivery, and workforce. We discuss the social determinants of health and health care disparities that affect patients in the community that require the attention of policy makers. Furthermore, we highlight the many needs of the growing adults with congenital heart disease and those with comorbidities, highlighting concerns regarding the inequities in access to cardiac care and the need for multidisciplinary care. We also recognize the problems of transparency in outcomes reporting and the promising application of telehealth. Finally, we highlight the training of providers, measures of productivity, diversity in the workforce, and the importance of patient-family centered organizations in advocating for patients. Although all of these issues remain relevant to many subspecialties in medicine, this article attempts to illustrate the unique needs of this population and highlight ways in which to work together to address important opportunities for change in the cardiac care community and beyond. This article provides a framework for policy and advocacy efforts for the next decade.

Myocardial Perfusion in Hypoplastic Left Heart Syndrome

BACKGROUND

The status of the systemic right ventricular coronary microcirculation in hypoplastic left heart syndrome (HLHS) is largely unknown. It is presumed that the systemic right ventricle's coronary microcirculation exhibits unique pathophysiological characteristics of HLHS in Fontan circulation. The present study sought to quantify myocardial blood flow by cardiac magnetic resonance imaging and evaluate the determinants of microvascular coronary dysfunction and myocardial ischemia in HLHS.

METHODS

One hundred nineteen HLHS patients (median age, 4.80 years) and 34 healthy volunteers (median age, 5.50 years) underwent follow-up cardiac magnetic resonance imaging ≈1.8 years after total cavopulmonary connection. Right ventricle volumes and function, myocardial perfusion, diffuse fibrosis, and late gadolinium enhancement were assessed in 4 anatomic HLHS subtypes. Myocardial blood flow (MBF) was quantified at rest and during adenosine-induced hyperemia. Coronary conductance was estimated from MBF at rest and catheter-based measurements of mean aortic pressure (n=99).

RESULTS

Hyperemic MBF in the systemic ventricle was lower in HLHS compared with controls (1.89±0.57 versus 2.70±0.84 mL/g per min; P<0.001), while MBF at rest normalized by the rate-pressure product, was similar (1.25±0.36 versus 1.19±0.33; P=0.446). Independent risk factors for a reduced hyperemic MBF were an HLHS subtype with mitral stenosis and aortic atresia (P=0.017), late gadolinium enhancement (P=0.042), right ventricular diastolic dysfunction (P=0.005), and increasing age at total cavopulmonary connection (P=0.022). The coronary conductance correlated negatively with systemic blood oxygen saturation (r, -0.29; P=0.02). The frequency of late gadolinium enhancement increased with age at total cavopulmonary connection (P=0.014).

CONCLUSIONS

The coronary microcirculation of the systemic ventricle in young HLHS patients shows significant differences compared with controls. These hypothesis-generating findings on HLHS-specific risk factors for microvascular dysfunction suggest a potential benefit from early relief of frank cyanosis by total cavopulmonary connection.

Pathways to Clinical Cardiac Xenotransplantation

Heart transplantation is the only long-lasting lifesaving option for patients with terminal cardiac failure. The number of available human organs is however far below the actual need, resulting in substantial mortality of patients while waiting for a human heart. Mechanical assist devices are used to support cardiac function but are associated with a high risk of severe complications and poor quality of life for the patients. Consistent success in orthotopic transplantation of genetically modified pig hearts into baboons indicates that cardiac xenotransplantation may become a clinically applicable option for heart failure patients who cannot get a human heart transplant. In this overview, we project potential paths to clinical cardiac xenotransplantation, including the choice of genetically modified source pigs; associated requirements of microbiological, including virological, safety; optimized matching of source pig and recipient; and specific treatments of the donor heart after explantation and of the recipients. Moreover, selection of patients and the regulatory framework will be discussed.