Systemic-Pulmonary Shunt Facilitates the Growth of the Pulmonary Valve Annulus in Patients With Tetralogy of Fallot.

BACKGROUND

Transannular patching (TAP) frequently accompanies primary repairs (PRs) in symptomatic neonates with tetralogy of Fallot (TOF). If a systemic-pulmonary shunt (SPS) facilitates the growth of the pulmonary valve annulus (PVA), patients with a marginally small PVA could benefit from a staged repair in terms of lowering the risk of TAP.

METHODS

Among 216 infants with TOF who underwent surgical intervention between January 2004 and December 2013, 29 infants underwent SPS with a subsequent repair (SPS group), whereas 187 infants received a PR (PR group). Median age and the Z-score of the PVA (PVA [Z]) at SPS were 32 days and -3.5, respectively. There was one late death and one follow-up loss after SPS, and preservation of the PVA was achieved on repair in 16 patients (16 of 29; 55%).

RESULTS

Multiple regression analysis showed that performance of SPS was the only indicator of the increase in the PVA (Z) in the entire cohort (n = 216). On mixed linear regression, the PVA (Z) increased significantly after the placement of an SPS (-3.6 + 0.2*duration in months, p = 0.001), whereas the prerepair changes in the PVA (Z) were not statistically significant in the PR group (p = 0.7), with a significant intergroup difference (p < 0.001). Receiver operating characteristic curve analysis showed that placement of TAP is expected when the preshunt PVA (Z) is smaller than -4.2 (area under the curve: 0.82; 95% confidence interval: 0.62 to 1.00; sensitivity, 100%; specificity, 73%).

CONCLUSIONS

SPS facilitates outgrowth of the PVA over somatic growth in patients with TOF. However, preservation of the PVA may not be achieved on staged repair if the initial PVA is too small.