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Right ventricular outflow tract growth in infants with palliated tetralogy of fallot
Eleanor T Ross1, John M Costello2, Carl L Backer3
1Division of Cardiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois.
Insights
A modified Blalock-Taussig shunt (mBTS) promotes significant pulmonary artery growth in neonates with tetralogy of Fallot with pulmonary stenosis (TOF/PS). This growth may aid in achieving valve-sparing repairs during complete surgical correction.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Disease
- Surgical Palliation
Background:
- Limited data exist on the impact of modified Blalock-Taussig shunt (mBTS) in neonates with tetralogy of Fallot with pulmonary stenosis (TOF/PS).
- The effects on pulmonary valve (PV) and pulmonary artery (PA) growth, and PV preservation during repair are not well-defined.
Purpose of the Study:
- To evaluate the effect of mBTS on pulmonary valve and artery growth in neonates with TOF/PS.
- To assess the incidence of pulmonary valve preservation at the time of complete surgical repair following mBTS palliation.
Main Methods:
- Retrospective study of patients undergoing TOF/PS repair between 2000-2012.
- Echocardiographic assessment of PV annulus, main PA (MPA), and branch PAs (LPA, RPA) size before mBTS and surgical repair.
- Analysis of growth and Z-scores of these structures in palliated versus non-palliated neonates.
Main Results:
- 40 of 172 (23%) neonates with TOF/PS received mBTS palliation; 31 had complete echocardiographic data.
- Palliated neonates showed significant absolute growth in PV, MPA, RPA, and LPA post-mBTS.
- Branch PA Z-scores improved significantly, while PV and MPA Z-scores remained unchanged. PV-sparing repair was achieved in 32% of palliated patients versus 88% of primary repairs.
Conclusions:
- Modified Blalock-Taussig shunt leads to significant absolute growth of the pulmonary valve, main pulmonary artery, and branch pulmonary arteries in neonates with TOF/PS.
- Branch PA size normalizes before complete repair, and absolute PV growth may facilitate valve-sparing repair in a subset of patients.
Background:
In symptomatic neonates with tetralogy of Fallot with pulmonary stenosis (TOF/PS), limited contemporary data exist regarding the effect of a modified Blalock-Taussig shunt (mBTS) on pulmonary valve (PV) and pulmonary artery (PA) growth and on the incidence of PV preservation at the time of complete repair.
Methods:
We retrospectively studied patients who underwent repair of TOF/PS from 2000 to 2012 at our center. In neonates with TOF/PS palliated with an mBTS, we assessed PV annulus, main PA (MPA), and branch PAs (left PA [LPA] and right PA [RPA]) size by echocardiography before mBTS and surgical repair.
Results:
Of 172 patients with TOF/PS, 40 (23%) were palliated with an mBTS at a median age of 23 days, and 31 met criteria for echocardiographic analysis. Palliated patients had hypoplastic PV, MPA, RPA, and LPA at baseline. All structures had significant absolute growth before surgical repair (p < 0.001). PV and MPA Z scores were unchanged, whereas branch PAs showed significant improvement (RPA, p = 0.03; LPA, p = 0.008). A PV-sparing repair was performed in 116 of 132 primary repairs (88%) and in 10 of 31 palliated patients (32%). At a median follow-up of 4.0 years (range, 0.7 to 12.6 years), no palliated patients required reintervention for right ventricular outflow tract obstruction.
Conclusions:
Significant absolute growth of the PV, MPA, RPA, and LPA occurs after an mBTS in neonates with TOF/PS. Branch PA size normalizes before complete repair. In one-third of patients with hypoplastic PVs, absolute growth after an mBTS may have facilitated valve-sparing repair.
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