Longitudinal Evaluation of Right Ventricle Function after Right Ventricle-Pulmonary Artery Shunt vs. Blalock-Taussig Shunt

Background: Still little is known about the impact on right ventricle function of the 2 main approaches to Norwood palliation in Hypoplastic left heart syndrome, the right ventricle-pulmonary artery shunt (RVPAS) and the modified Blalock-Taussig shunt (mBTS). Methods: The cohort included 27 patients with Hypoplastic left heart syndrome (10 in the mBTS group, 17 in the RVPAS group). Longitudinal strain, tricuspid annulus peak systolic excursion and fractional area change were evaluated before Norwood and in four different breakpoints in the steady-state after Norwood procedure (30-days, 90-days, 140-days and 200-days after Norwood). Results: No significant differences were found in all standard echocardiographic functional parameters between the two groups at any times. However, when we compared right ventricle function before and after Norwood procedure, longitudinal strain significantly improved in mBTS group compared to pre-surgical assessment (after 90-days: mBTS +27,35% +/- 43,47 vs. RVPAS -8,20% +/- 25,25, p = 0,03; after 200-days: mBTS +10.19% +/- 36.58 vs. RVPAS -21.64% +/- 30.43, p = 0.04). Conclusion: The mBTS group, which did not receive any ventriculotomy, showed a significant increase in right ventricle longitudinal strain during convalescence. These data support the use of longitudinal strain in Hypoplastic left heart syndrome evaluation and may suggest potential value in terms of cardiac mechanics in using mBTS, preserving the right ventricle integrity.