Long-term therapeutic effect of Fontan conversion with an extracardiac conduit

The aim of this study was to identify the long-term therapeutic effect of total cavopulmonary connection (TCPC) conversion with an extracardiac conduit.

Between 1991 and 2014, 36 patients underwent TCPC conversion with an extracardiac conduit. Half of these patients were diagnosed with tricuspid atresia or its variant. The left ventricle was dominant in 26 patients (72.2%). Median age at conversion and interval from initial Fontan operation to conversion were 24.1 years (interquartile range 18.9-29.2) and 17.8 years (15.4-20.9), respectively. Surgical cryoablation was concomitantly performed in 32 patients (88.9%). Cardiac catheter examination was performed preoperatively (36 patients, 100%) and at 1 year (31 patients, 86%), 5 years (25 patients, 69%) and 10 years (13 patients, 36%) after TCPC conversion. Symptom-limited treadmill exercise with expired gas analysis was performed preoperatively (32 patients, 88.9%) and at 1 year (27 patients, 75.0%), 5 years (20 patients, 55.6%) and 10 years (12 patients, 33.3%) after conversion.

All patients received follow-up; the mean follow-up period was 8.2 ± 4.8 years. Actuarial survival rate, protein-losing enteropathy-free survival rate and rate of survival with sinus rhythm maintenance at 10 years were 79.2%, 67.8% and 48.5%, respectively. The survival curve declined steeply when the duration of Fontan circulation exceeded 25 years. New cases of protein-losing enteropathy developed postoperatively in 2 patients. Permanent pacemakers were implanted in 12 patients (33%), but atrial tachyarrhythmia was not sustained in any of the remaining patients. Pulmonary arterial pressure (11.0 ± 3.1 to 9.5 ± 3.6 mmHg, P = 0.003), pulmonary vascular resistance (2.1 ± 0.7 to 1.3 ± 0.5 WU/m2, P < 0.0001) and cardiac index (2.0 ± 0.3 to 2.9 ± 0.6 l/min/m2, P < 0.0001) significantly improved from preoperative evaluation to 1 year after the conversion, and these improvements were maintained during the entire follow-up period. Peak oxygen uptake remained unchanged from the preoperative evaluation (49.7 ± 11.5% predicted) to 1 year (52.5 ± 12.0%), 5 years (56.2 ± 9.6%) and 10 years (51.2 ± 9.4%) after conversion (P = 0.19).

Owing to its anti-arrhythmic effect and Fontan pathway recruitment effect, TCPC conversion with an extracardiac conduit prevented the natural decline of exercise tolerance that is seen in classic Fontan patients.