Right ventricle function longitudinal evaluation after norwood procedure: comparison between right ventricle-pulmonary artery shunt and blalock-taussing shunt

Abstract

Abstract Background Norwood procedure represents the first of three surgical steps toward Hypoplastic left heart syndrome (HLHS) complete palliation. Two are the main surgical techniques allowing the reconstruction of Norwood circulation: the right ventricle-pulmonary artery shunt (RVPAS) and the modified Blalock-Taussing shunt (mBTS). However, still little is known about the impact on right ventricle (RV) function of the required ventriculotomy for the RVPAS. Purpose The aim of the study was to investigate the changes in RV function in HLHS patients after RVPAS vs mBTS. Methods The cohort included 27 consecutive HLHS patients (10 in the modified Blalock-Taussig shunt group and 17 in the RVPAS group) who successfully underwent Norwood procedure in a single tertiary paediatric cardiology centre. Longitudinal strain (LS) and strain rate (LSR), tricuspid annulus peak systolic excursion (TAPSE) and fractional area change (FAC) were evaluated in all patients before Norwood and in three different breakpoints in the steady state after Norwood procedure (30 days after Norwood, 90 days after Norwood, 140 days after Norwood). Results Ventricular loading conditions (diuretic treatment, blood pressure and tricuspid regurgitation) were similar in both groups. No significant differences were found at different time points between RVPAS and mBTS group in terms of LS, LSR, TAPSE and FAC. However, when we compared RV function before and after Norwood procedure, 90 days after the procedure, patients who did not undergo RV ventriculotomy (mBTS group) showed significant improvement in LS compared to pre-surgical assessment (mBTS: +27.35±43.47% vs RVPAS: −8,20±25.25%, p=0,03). This finding was consistent but no longer statistically significant at 140 days after Norwood (mBTS: +13.81±21.99% vs RVPAS: −4.90±27.97%, p=0,12). Conclusion After Norwood procedure mBTS patients showed a significant increase in LS when compared with patients who underwent RVPAS. This finding was consistent but no longer significant at 140 days after Norwood probably because the number of patients was too small to reach a significant level. These data support the use of LS in HLHS patient's evaluation and may be of value to find a patient-tailored timing for the second surgical stage. TAPSE, FAC, LS and LSR trends Funding Acknowledgement Type of funding source: None