Stenting of the Right Ventricular Outflow Tract Promotes Better Pulmonary Arterial Growth Compared With Modified Blalock-Taussig Shunt Palliation in Tetralogy of Fallot-Type Lesions.

OBJECTIVES: This study sought to compare pulmonary arterial (PA) growth during palliation after right ventricular outflow tract (RVOT) stenting versus modified Blalock-Taussig shunt (mBTS) in patients coming forward for complete repair of tetralogy of Fallot-type lesions.

BACKGROUND: RVOT stenting is a recent alternative to mBTS in the initial palliation of selected patients with Fallot-type lesions.

METHODS: This was a retrospective, single-center study of nonrandomized, consecutive palliated Fallot patients over a 10-year period. Differential left PA (LPA) and right PA (RPA) growth was assessed by serial echocardiograms in 67 patients after mBTS (n = 28) or RVOT stent (n = 39). Statistical data analysis was performed using mixed model analysis.

RESULTS: RPA z-scores in the mBTS group improved from median -2.41 (interquartile range [IQR]: -2.97 to -1.32) to -1.13 (IQR: -1.68 to -0.59). LPA z-scores improved from -1.89 (IQR: -2.33 to -1.12) to -0.32 (IQR: -0.88 to -0.05). In the RVOT stenting group RPA z-scores improved from -2.28 (IQR: -3.28 to -1.82) to -0.72 (IQR: -1.27 to +0.48), and LPA z-scores from -2.08 (IQR: -2.90 to -0.61) to -0.05 (IQR: -0.88 to +0.48). Mixed model analysis showed significantly better RPA and LPA growth after RVOT stenting. The benefit of RVOT stenting versus mBTS was 0.599 z-scores for the LPA and 0.749 z-scores for the RPA. Rise in oxygen saturations was greater with RVOT stenting (p = 0.012). Median time to complete repair was shorter in the RVOT stent group (227 [142 to 328] days) compared with the mBTS group (439 [300 to 529] days; p < 0.0003).

CONCLUSIONS: RVOT stenting promotes better pulmonary arterial growth and oxygen saturations compared with mBTS in the initial palliation of Fallot-type lesions.