Mechanism and Risk Factors for Death in Adults With Tetralogy of Fallot

One of the goals of lifelong care in adults with tetralogy of Fallot (TOF) is early identification and treatment of patients at high risk for adverse events. Clinical risk stratification tools are critical for achieving this goal. We reviewed the Mayo Adult Congenital Heart Disease database and identified 465 TOF patients (age 37 ± 14 years, men 223 [48%]) seen at Mayo Clinic Rochester between 1990 and 2017. The aim was to determine the risk factors for death and/or heart transplant through a comprehensive analysis of 8 groups of variables (demographics, co-morbidities, medications, heart rhythm, echocardiography, cardiac magnetic resonance imaging, cardiac catheterization, and cardiopulmonary exercise test data) using univariable and multivariable Cox proportional hazard models. The end point of death and/or transplant occurred in 57 (12%) patients during a follow-up of 13.6 ± 8.2 years, yielding an event rate of 0.9% per year. Independent risk factors were age >42 years, atrial fibrillation, ≥moderate QRS fragmentation, left ventricular ejection fraction <50%, right ventricular end-diastolic pressure >16 mm Hg, and left ventricle end-diastolic pressure >16 mm Hg. There is nearly a twofold increase in the risk of death and/or transplant per unit increase in number of risk factors (hazard ratio 1.92, 95% confidence interval 1.62 to 2.27, p <0.001). In conclusion, the current study provides risk stratification indices based on a comprehensive risk model of all clinical variables in an unselected TOF population. Further studies are required to determine whether interventions targeted at modifying these risk factors will alter the annual event rate.