Impact of Systemic Pulmonary Shunt for Tetralogy of Fallot on Pulmonary Valve Annulus Growth and Midterm Pulmonary Valve Function.

BACKGROUND: Tetralogy of Fallot (TOF) often requires transannular patch repair, leading to pulmonary regurgitation. Systemic pulmonary shunt can be associated with pulmonary valve annulus (PVA) growth, thus potentially enabling valve-sparing repair. This study evaluated PVA growth after systemic pulmonary shunt and the midterm impact of valve-sparing repair on pulmonary valve function. METHODS: We reviewed 54 patients with TOF who underwent staged repair with systemic pulmonary shunt. PVA z scores were compared before and after systemic pulmonary shunt. Freedom from pulmonary regurgitation (PR) was assessed. Freedom from PR was defined as PR less than moderate. RESULTS: The median follow-up duration after intracardiac repair was 7.6 years (interquartile range [IQR], 3.1-10.8 years). In the staged repair group, the median PVA z score increased from -3.4 (IQR, -5.2 to -2.6) at the time of systemic pulmonary shunt to -2.7 (IQR, -4.4 to -1.8) before intracardiac repair. Freedom from PR at 8 years after intracardiac repair was higher in the valve-sparing repair group (84% vs 45%; P = .009). The pre-systemic pulmonary shunt PVA z score was a significant predictor of PVA growth (odds ratio, 1.87; P = .002), with a threshold of -4.1 predicting growth with 82.1% sensitivity and 72.7% specificity. CONCLUSIONS: PVA growth was observed in patients with TOF after systemic pulmonary shunt. The pre-systemic pulmonary shunt PVA z score predicts successful growth and informs surgical planning. Valve-sparing repair offers superior midterm freedom from PR compared with transannular patch repair.