Risk factors for sudden death after repair of tetralogy of Fallot

Background Sudden cardiac death remains the most common cause of death after repair of tetralogy of Fallot. It has been suggested that sudden cardiac death is related to right ventricular hypertrophy or dilation. However, it is uncertain whether the preoperative patient status or operative techniques predispose for sudden cardiac death. Methods From 1958 to 1977, 658 patients underwent repair of tetralogy of Fallot at our institution at a median age of 12.2 ± 8.6 years. One third had at least one previous palliative operation 4.6 ± 2.5 years earlier. A total of 490 patients survived the first postoperative year and were analyzed for sudden cardiac death. During a follow-up period of 25.3 ± 5.8 years (range, 1.0 to 35.5 years), 42 patients died, and 15 (36%) of those deaths were as a result of sudden cardiac death. Results Actuarial 10-year, 20-year, and 30-year survival rates were 97%, 94%, and 89%. Freedom from sudden cardiac death was 99%, 98%, and 95% after 10, 20, and 30 years. The risk of sudden cardiac death increased after 10 years from 0.06%/y to 0.20%/y. Univariate predictors (p< 0.1) of sudden cardiac death were use of an outflow tract patch (p = 0.068), male sex (p = 0.048), no previous palliation (p = 0.013), and higher preoperative New York Heart Association status (p = 0.014). Multivariate analysis confirmed these risk factors except use of an outflow tract patch. Conclusions The most important risk factors for sudden cardiac death were higher preoperative New York Heart Association class and no previous palliation. Thus, early surgical intervention is recommended. The risk of sudden cardiac death increases with time, suggesting that long-term follow-up by specialized cardiologists or pediatricians should be intensified. However, all patients who died suddenly had at least two risk factors at the time of surgery.