The natural and unnatural history of the Mustard procedure: long-term outcome up to 40 years

Aims To describe long-term survival, clinical outcome and ventricular systolic function in a longitudinally followed cohort of patients after Mustard repair for transposition of the great arteries (TGA). There is serious concern about the long-term outcome after Mustard repair. Methods and results This longitudinal single-centre study consisted of 91 consecutive patients, who underwent Mustard repair before 1980, at age < 15 years, and were evaluated in-hospital every 10 years. Survival status was obtained of 86 patients. Median follow-up was 35 (IQR 34-38) years. Cumulative survival was 84% after 10 years, 80% after 20 years, 77% after 30 years, and 68% after 39 years. Cumulative survival free of events (i.e. heart transplantation, arrhythmias, reintervention, and heart failure) was 19% after 39 years. Reinterventions were mainly required for baffle-related problems. Supraventricular and ventricular arrhythmias occurred in 28 and 6% of the patients, respectively. Pacemaker and/or ICD implantation was performed in 39%. Fifty survivors participated in the current in-hospital investigation including electrocardiography, 2D-echocardiography, cardiopulmonary-exercise testing, NT-proBNP measurement, Holter monitoring, and cardiac magnetic resonance. Right ventricular systolic function was impaired in all but one patient at last follow-up, and 14% developed heart failure in the last decade. NT-proBNP levels [median 31.6 (IQR 22.3-53.2) pmol/L] were elevated in 92% of the patients. Early postoperative arrhythmias were a predictor for late arrhythmias [HR 3.8 (95% CI 1.5-9.5)], and development of heart failure [HR 8.1 (95% CI 2.2-30.7)]. Also older age at operation was a predictor for heart failure [HR 1.26 (95% CI 1.0-1.6)]. Conclusion Long-term survival after Mustard repair is clearly diminished and morbidity is substantial. Early postoperative arrhythmias are a predictor for heart failure and late arrhythmias.