Long-term outcomes of Tetralogy of Fallot following complete repair

George, Joseph ORCID: 0000-0002-2590-5952 (2024). Long-term outcomes of Tetralogy of Fallot following complete repair. University of Birmingham. M.Sc.

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Abstract

Background: Tetralogy of Fallot (ToF) is the most common cyanotic heart defect, requiring not only early surgery in infancy, but usually one or more cardiac catheter interventions or open-heart operations into adulthood. Although ToF is ‘completely repaired’ at the initial surgery by closing the ventricular septal defect (VSD) and relieving the obstruction to pulmonary blood flow, it invariably leaves severe pulmonary valve regurgitation with volume loading of the right ventricle (RV). Over time, the RV dilates and will eventually fail without further intervention to implant a pulmonary valve prosthesis. We analysed early and late outcomes of ToF in one of the largest single-centre cohorts of both paediatric and adult congenital cardiac surgery in the UK, with a consistent approach to operative management over more than 30 years.

Methods: All patients who underwent complete repair of ToF over a 34-year period (1988-2022) in a single centre were included. Comparisons between morphological groups were undertaken using the Kruskal-Wallis tests for continuous variables, or Pearson's chi-squared test for categorical variables. Kaplan-Meier estimates were generated as all-cause mortality curves for the time-to- event analysis, and comparison between groups using the log-rank test. Event rates for reinterventions were estimated using cumulative incidence function with death as the competing risk.

Results: 821 patients were included in the final analysis with a median follow-up of 15.1 years over a study period of 34.3 years. 24% underwent a pre-repair intervention: either a systemic-to-pulmonary shunt or a right ventricular outflow tract stent. Median age at repair was 0.98 years with 95% of patients undergoing a trans-atrial approach to the VSD closure. 74.4% required a transannular patch. Long-term survival was 92.5% at 30 years. Median interval from complete repair to pulmonary valve replacement (PVR) was 18.2 years. Incidence of PVR at 25 years was 39.1% with 50% of patients needing a PVR at 27 years. Following PVR, there was a decrease in the indexed right ventricular dimensions including end-diastolic volume (from 119ml/m2 to 103ml/m2) and end- systolic volume (84ml/m2 to 52ml/m2) with an associated increase in the right ventricular ejection fraction.

Conclusions: We demonstrate excellent long-term results for Tetralogy of Fallot over a 34-year study period with evidence of reverse remodelling following pulmonary valve replacement. This study provides a sound evidence-base to counsel parents about long-term outlook for children treated with Tetralogy of Fallot.

Type of Work:

Thesis (Masters by Research > M.Sc.)

Award Type:

Masters by Research > M.Sc.

Supervisor(s):