Comparison of Ozaki Technique and Ross Procedure in Children with Complex Aortic Valve Diseases

Academic Background

Aortic valve disease (AVD) in children is a complex and challenging condition, especially when surgical intervention is required. Traditional aortic valve replacement surgeries, such as mechanical or bioprosthetic valve replacements, have several limitations in pediatric patients, including valve size mismatch, the need for long-term anticoagulation therapy, and issues with valve durability. The Ross procedure is considered the gold standard for complex aortic valve diseases in children, but it also has certain limitations, such as the risk of dual-valve degeneration and restrictions on surgical indications.

In recent years, the Ozaki technique has emerged as a novel aortic valve repair method, showing promising results in adult patients. This technique involves reconstructing the aortic valve leaflets using autologous pericardium to restore physiological valve function. However, there is a lack of long-term follow-up data on the application of the Ozaki technique in pediatric patients, particularly in comparison to the Ross procedure. Therefore, this study aims to evaluate the mid-term outcomes of the Ozaki technique in children with complex aortic valve diseases and compare them with those of the Ross procedure.

Source of the Paper

This paper was co-authored by Guan-Xi Wang, Sen Zhang, Kai Ma, and others, affiliated with Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College. The study was published online on July 18, 2024, in the International Journal of Surgery.

Research Process

Study Subjects and Grouping

This retrospective cohort study included 117 pediatric patients who underwent either the Ozaki technique (64 cases) or the Ross procedure (53 cases) between January 2017 and December 2023. All patients were diagnosed with complex aortic valve diseases and were under 18 years of age. The primary endpoint was the incidence of moderate or severe aortic regurgitation (AR) or stenosis (AS) postoperatively.

Surgical Techniques

• Ozaki Technique: This technique involves complete excision of the diseased aortic valve leaflets and reconstruction using autologous pericardium. The pericardium is treated with 0.6% glutaraldehyde to ensure durability. Depending on the pathology, single, double, or triple leaflet reconstruction may be performed.
• Ross Procedure: The standard full root technique was used for aortic valve replacement, along with right ventricular outflow tract reconstruction.

Data Collection and Analysis

Preoperative, intraoperative, and postoperative data were collected, including age, weight, preoperative cardiac function, surgical duration, and postoperative complications. Echocardiography was used to assess postoperative aortic valve function, including the severity of valve regurgitation and stenosis. Statistical analysis employed the Cox proportional hazards regression model to identify risk factors for moderate or severe AR/AS.

Key Findings

Preoperative and Intraoperative Results

• Preoperative Status: Patients in the Ozaki group had poorer preoperative cardiac function, with 20.3% experiencing heart failure (compared to 1.9% in the Ross group). Additionally, 6.3% of Ozaki group patients required extracorporeal membrane oxygenation (ECMO) support postoperatively (0% in the Ross group).
• Surgical Duration: Cardiopulmonary bypass time and aortic cross-clamp time were significantly shorter in the Ozaki group compared to the Ross group.

Postoperative Follow-Up Results

• Reoperation Rate: Five patients (7.8%) in the Ozaki group required reoperations, while no reoperations were needed in the Ross group.
• Aortic Valve Function: The incidence of moderate or severe AR and AS was significantly higher in the Ozaki group (AR: 28.1% vs. 3.8%; AS: 31.3% vs. 5.7%).
• Survival Rate: The 1-year, 3-year, and 5-year survival rates in the Ozaki group were 93.2%, 86.6%, and 86.6%, respectively, compared to 100% across all time points in the Ross group.

Risk Factor Analysis

• Risk Factors for AR: Multivariate analysis identified younger age at surgery and ECMO installation as independent risk factors for moderate or severe AR in the Ozaki group.
• Risk Factors for AS: A higher aortic transvalvular gradient before discharge was the only risk factor for moderate or severe AS in the Ozaki group.

Conclusion

The study suggests that the Ozaki technique can serve as a palliative surgical option for complex aortic valve diseases in children, but its mid-term outcomes are less durable than those of the Ross procedure, particularly in younger patients. Therefore, the Ross procedure may be a preferable choice for younger patients.

Research Highlights

1. Innovation: This study is the first to compare the mid-term outcomes of the Ozaki technique and the Ross procedure in a large pediatric cohort, filling a gap in this field.
2. Clinical Significance: The findings provide important insights for surgical decision-making in children with complex aortic valve diseases, particularly for patients who are not suitable candidates for the Ross procedure, as the Ozaki technique offers a viable alternative.
3. Methodological Strengths: The study employed rigorous multivariate analysis to identify key risk factors affecting the outcomes of the Ozaki technique, offering a basis for future surgical optimization.

Additional Valuable Information

• Limitations: As a retrospective study, the poorer preoperative cardiac function in the Ozaki group may limit the generalizability of the results. Future multicenter studies and longer follow-up periods are needed to validate the conclusions.
• Future Directions: Further research should focus on the broader application of the Ozaki technique in pediatric patients, particularly its long-term outcomes and valve durability.