TRIVIA : Tetralogy of Fallot Research for Improvement of Valve replacement Intervention : A bridge across the knowledge gap

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect. Its surgical repair during the first year of life provides excellent short-term results, but some anomalies may persist, leading to long-term complications. The TRIVIA study is a cohort including all patients born in Quebec with a TOF between 1982 and 2017. The cohort database combines administrative data from the healthcare system with clinical data from the four Quebec pediatric cardiology centers. The TRIVIA study assessed the impact of treatments on the long-term prognosis of those with TOF.

Associated genetic syndromes: Many persons living with a cardiac malformation also have genetic syndromes (e.g., trisomy 21 or deletion 22q11). In our cohort, we have seen those with a syndrome had a poorer prognosis than those without a genetic syndrome, putting them at greater risk of mortality.

 Subtypes of TdF: There are two main types of TdF, the form with pulmonary stenosis (classic form) and that with pulmonary atresia (severe). We sought to explore the differences in prognosis associated with the TOF subtype. We found that the severe form was associated with a much higher mortality in infancy, as well as an increased risk of cardiac interventions and hospitalization, compared with the classic form. The results of this study help us to better advise families on the long-term outcome of children with TOF.

 Corrective surgery: People born with a TOF require surgery to correct the anatomical defects associated with the TOF in the first year of life. Two main methods exist: the transannular patch method, a long-standing surgical procedure, and the pulmonary valve preservation method, a more recent procedure that reduces pulmonary valve leakage, but may cause greater obstruction. Compared with the transannular patch method, pulmonary valve preservation surgery was associated with lower mortality and a reduced risk of cardiac interventions.

Early pulmonary valve replacement: One consequence of ToF correction surgery is that it can, in some cases, damage the pulmonary valve. As a result, many will require pulmonary valve replacement (PVR). A more recent surgical trend is to offer a PVR to those with a TOF before they reach adulthood, so that they don’t develop complications related to their no longer perfectly functioning pulmonary valve, rather than waiting until adulthood. We have seen that a PVR performed in adolescence was not associated with clear benefits in terms of survival, number of interventions and hospitalizations compared with a PVR performed in adulthood.

Loss to follow-up in cardiology : We wanted to explore what the risk factors were for being lost to follow-up, and whether loss to follow-up had adverse consequences on the health of those living with a TOF. We found that what put those with a TOF most at risk of being lost to follow-up was having corrective pulmonary valve-preserving surgery. Also, those who were lost to follow-up were hospitalized less often, underwent fewer cardiac procedures, but were at greater risk of death.

Thanks to the TRIVIA cohort, we have been able to better understand the trajectories of persons living with a TOF in order to better guide long-term management.

• Blais S, Marelli A, Vanasse A, et al. The TRIVIA Cohort for Surgical Management of Tetralogy of Fallot: Merging Population and Clinical Data for Real-World Scientific Evidence. CJC Open. 2020;2:663-670.
• Blais S, Marelli A, Vanasse A, et al. The 30-Year Outcomes of Tetralogy of Fallot According to Native Anatomy and Genetic Conditions. Can J Cardiol. 2021;37:877-886.
• Blais S, Marelli A, Vanasse A, et al. Comparison of Long-term Outcomes of Valve-Sparing and Transannular Patch Procedures for Correction of Tetralogy of Fallot. JAMA Netw Open. 2021;4:e2118141.
• Roy LO, Blais S, Marelli A, et al. Determinants and Clinical Outcomes of Patients With Tetralogy of Fallot Lost to Cardiology Follow-up. Can J Cardiol. 2024;40:411-418.
• Roy LO, Blais S, Marelli A, et al. Outcomes After Pediatric Pulmonary Valve Replacement in Patients With Tetralogy of Fallot. Can J Cardiol. 2024;40:2461-2472.