Congenital

A new study sheds light on the challenges of pediatric mitral valve replacement (MVR) and evaluates the potential of the balloon-expandable Melody valve as an alternative to traditional mechanical prostheses. The findings offer important insights for treating young children with small mitral annuli, a population for whom MVR carries significant risks of morbidity and mortality.

A team of researchers, led by Morgan Moroi, MD, New York-Presbyterian/Columbia University Medical Center, conducted a retrospective review of 36 children under 2 years of age who underwent MVR at a single center between 2005 and 2023. Using propensity score matching to minimize baseline differences, the study compared outcomes between 12 patients receiving the Melody valve and 12 patients treated with mechanical prostheses.

The primary outcome was a composite measure of death, transplant, or surgical reintervention on the mitral valve prosthesis. Median follow-up was 1.6 years.

Key Findings

Both groups had similar baseline characteristics, with a median age of 5.2 months and median weight of 6.5 kg at the time of surgery. The study revealed several important differences and similarities in outcomes:

• Hospital Stay: Melody valve patients had shorter hospital stays (median: 20.5 days) compared to mechanical valve patients (median: 59.0 days), though the difference was not statistically significant (P=0.11).
• Mitral Valve Gradients: The Melody valve group had significantly lower mitral valve gradients at discharge (5.5 mmHg vs. 8.7 mmHg, P=0.046).
• Permanent Pacemakers: No patients in the Melody group required a permanent pacemaker, while 41.7% of the mechanical group did (P=0.04).
• Reintervention Rates: Both groups experienced early surgical reinterventions at similar rates (33.3% vs. 25%, P=1.00).
• Survival Outcomes: At 1 and 3 years, transplant-free survival was comparable between the groups, with no significant difference (P=0.92).
   

Implications 

The findings suggest that the Melody valve offers several advantages over mechanical prostheses in young children with small mitral annuli, including lower rates of permanent pacemaker insertion and no need for lifelong anticoagulation. While early reintervention rates were high across both groups, the Melody valve demonstrated equivalent survival outcomes and may provide a safer and more effective option for this vulnerable patient population. However, the study authors emphasize the need for further research with larger cohorts and longer follow-up to confirm these promising results.
 

Evaluating the performance of congenital heart surgery centers is essential for improving patient outcomes. However, traditional methods of assessing performance have their limitations. At yesterday’s STS 2025 session, Sharon-Lise Normand, PhD, a professor of health care policy at Harvard Medical School, presented Improving Risk Adjustment in the Assessment of Congenital Heart Center Surgical Quality, which explored the use of modern causal inference techniques. These techniques aimed to better account for differences in case mix across centers, enhance risk adjustment, and provide a more accurate evaluation of center performance.

Utilizing data from the STS Congenital Database over a five-year period, the study examined 115 heart surgery centers across the United States. It compared two approaches for predicting postoperative mortality rates:

1. Traditional Method: This approach employed a statistical model that included data from all types of heart surgeries, even those that differed significantly from the procedures performed at the specific center.
2. Causal Inference Method: In contrast, this method focused on identifying other centers that performed similar surgeries and compared the outcomes of patients at those centers to those at the center under study.

Key findings

Dr. Normand discussed how the study revealed that causal inference methods yielded significantly higher and more variable estimates of expected mortality compared to traditional regression models. This suggests that traditional methods may underestimate the complexity of risk adjustment and the variability in performance across different centers. Additionally, causal inference methods were more effective in aligning the distribution of risk factors between comparison and target centers, leading to more accurate estimates of expected mortality.

Implications

These findings emphasize the potential of causal inference methods to provide a more tailored approach to risk adjustment, enhancing the accuracy of performance assessments across various centers. “Further research is needed to explore the implications of these methods for quality improvement and reporting,” said Dr. Normand. “By refining risk adjustment techniques, we can more effectively identify high-performing centers, pinpoint areas for improvement, and ultimately contribute to better outcomes for patients with congenital heart disease.”
 

The Congenital Heart Surgery Clark Paper, Understanding Mortality Following Congenital Heart Surgery: What Do Procedure-Specific Factors (PSF) Add? will assess the contribution of PSFs beyond standard risk factors in estimating mortality in this population.

Meena Nathan, MD, a pediatric cardiac surgeon at Children’s Hospital Boston, will present this paper on Friday, Jan. 24, from 2:16 to 2:24 p.m. as part of the "The Tribulations of Trials: Challenges in CHD Clinical Studies" session. During her talk, she will discuss data from The Society of Thoracic Surgeons Congenital Heart Surgery Database, a crucial resource for enhancing the quality of congenital heart surgery. In 2013, the Database expanded to include 82 Patient Safety Factors (PSFs) for benchmark operations (BMOs), though the impact of these PSFs on mortality prediction has yet to be fully explored.

To address this knowledge gap, Dr. Nathan and her team analyzed the contribution of PSFs to mortality estimation beyond standard STS risk factors. The study included a large cohort of BMOs from 115 U.S. centers between 2017 and 2022.

Dr. Nathan will present study findings, which emphasize the complexity of mortality prediction in congenital heart surgery and highlight the need for continued research to identify the most relevant risk factors and PSFs for each procedure, with the goal of developing more accurate prediction models that enhance patient care and support informed decision-making.

During the Saturday, Jan. 25 presentation of the James S. Tweddell Memorial Paper for Congenital Heart Surgery, Reilly Hobbs, MD, from the University of Utah Medical Center will explore the relationship between the volume of Norwood procedures performed at a center and patient outcomes based on findings from the National Pediatric Cardiology – Quality Improvement Collaborative Database study.

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The Norwood procedure, a critical surgery for infants with single ventricle defects, has been extensively studied, but findings on how case volume affects outcomes have been inconsistent. This study examines data that clarifies the relationship between center case volume and survival and morbidity in patients undergoing this complex surgery.

In presenting the findings of the study, Congenital Heart Surgery, Volume-Outcome Relationship of Norwood Procedures: Insights from the National Pediatric Cardiology – Quality Improvement Collaborative Database, Dr. Hobbs will explain how centers were grouped based on their annual case volume—low, medium, and high—and how preoperative risk factors, complications, and survival outcomes were compared. He will also highlight how patients at high-volume centers had better outcomes than those at low-volume centers, including higher survival rates and lower mortality, particularly among patients with additional high-risk features. 

“The findings indicate that the number of Norwood procedures performed at a center significantly impacts patient outcomes with high-volume centers consistently achieving better results than low-volume centers,” says Dr. Hobbs. “It’s essential to emphasize the role of case volume in complex congenital heart surgeries and explore the potential benefits of directing high-risk patients to more experienced centers. Further research is needed to identify the key factors that contribute to improved outcomes at high-volume centers, ultimately enhancing care for single ventricle patients.”
 

Coarctation, a condition which comprises 4-5% of all congenital heart disease cases, is the second most common congenital heart defect  requiring neonatal intervention. Yet there is a lack of guidance regarding aspects of its management in neonates and infants, primarily due to heterogeneity in phenotype, making consensus in management challenging.

Recently, the STS Workforce on Evidenced-Based Surgery and its Task Force on Congenital Heart Surgery formed a panel of congenital cardiac surgeons, cardiologists, and intensivists to provide guidance to specialists who manage isolated coarctation in neonates and infants¹. 

Methods

The multi-disciplinary Task Force members first identified key questions related to the care of these patients using the PICO Framework (Patients/Population, Intervention, Comparison/Control, Outcome). After performing a literature search for each question, practice guidelines were developed using a modified Delphi method with a “recommendation” classification and evidence level, which were graded using Class of Recommendations (COR) and Level of Evidence (LOE) based on AAC/AHA classification system².

Results

The following recommendations reached a “consensus,” which meant that 80% of panel members voted on them, and 75% of them agreed with these statements:  

• For neonates and infants with isolated coarctation, surgery is indicated in the absence of obvious surgical contraindications for those with prematurity, low weight, or other risk factors for surgical intervention. 
• For patients with risk factors for surgery, medical management prior to intervention is reasonable. 
• For those without associated arch hypoplasia, repair via thoracotomy is indicated. 
• For those with associated arch hypoplasia that cannot be adequately addressed via thoracotomy, repair via sternotomy is preferable. 
• For those with bovine arch anatomy, repair via sternotomy may be reasonable given the potential increased risk of recoarctation with bovine arch anatomy repaired via thoracotomy
• For those undergoing repair via sternotomy, antegrade cerebral perfusion or limited duration deep hypothermic circulatory arrest may be reasonable
• For those undergoing repair via sternotomy, extended end-to-end, arch advancement (end-to-side reconstruction with ligation of isthmus), and patch augmentation are all reasonable techniques

Conclusions

After completing the evaluation, Task Force members concluded that surgery remains the standard of care for managing isolated coarctation in neonates and infants. Depending on degree and location, arch hypoplasia may require a sternotomy approach rather than a thoracotomy approach. Significant opportunities remain to delineate management in these patients better.

Although these statements provide guidance considering the available data, they are not intended to be prescriptive, and practitioners should apply these based on their experience, as well as within the clinical setting in which they work.

"Some of these guidelines' most valuable aspects summarize the data related to thoracotomy vs. sternotomy, which is a continued area of debate," said the study's lead author, Dr. Elizabeth Stephens, associate professor of surgery at Mayo Clinic in Rochester, Minn.  "The decision is often relatively subjective and based on the surgeon's training and/or experience."

This paper reveals the many questions that still need to be studied and answered. "The good news is that we as a specialty have moved from ensuring survival in these patients to decreased morbidities related to surgery, but the next step is studying long-term outcomes and how to improve them, namely freedom from hypertension and late reintervention," added Dr. Stephens.

Read the Annals article, which will soon be published in the upcoming September 2024 issue (Vol 118, No. 3) of The Annals of Thoracic Surgery. 

References:

1. Stephens EH, Ahmad D, Alsoufi B, Anderson BR, Ashfaq A, Bleiweis MS, Dearani JA, d’Udekem Y, Feins EN, Jacobs JP, Karamlou T, Marino BS, Najm HK, Nelson JS, St. Louis JD, Turek JW, The Society of Thoracic Surgeons Clinical Practical Guidelines on the Management of Neonates and Infants with Coarctation, The Annals of Thoracic Surgery (2024)

2. Class of Recommendation (COR) and Level of Evidence (LOE); Further Evolution of the ACC/AHA Clinical Practice Guideline Recommendation Classification System: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Journal of the American College of Cardiology, 67(13), 1572–1574. https://doi.org/10.1016/j.jacc.2015.09 

During this session, investigators unveiled findings from the largest multicenter study of post-arterial switch operations (ASO) that resulted in increased survival rates for adolescents and adult patients – as well as an increase in the potential for these patients to require cardiac reoperations to address arterial switch related complications that arise later in life.

At day two's presentation on “Burden of Reoperative  Cardiac Surgery among Adolescents and Adults Who Have Undergone Prior Arterial Switch Operation: Society of Thoracic Surgeons Database Analysis,” Bret Mettler, MD, from Johns Hopkins University, examined a multi-year assessment of the prevalence and types of cardiac surgical interventions in patients who previously underwent ASO using data from the STS National Database. 

“Anatomical repair of transposition of the great arteries (TGA) and related anomalies by arterial switch operation (ASO) achieves a normal anatomic and physiologic cardiac configuration,” said Dr. Mettler.  “And as survival rates have increased, so have the potential for these patients to require cardiac reoperations to address resulting ASO-related complications.”

As most reoperations involved multiple procedures, the presentation examined how a hierarchical stratification of procedure categories was established, with each eligible surgical hospitalization assigned to the single highest applicable hierarchical category.
  
Dr. Mettler's presentation also examined implications for surgical counseling, post-operative clinical surveillance, and therapeutic management. An analysis of the role of procedural prevalence, timing, categories, trends, and the growing number of reoperations was discussed.