[I-P09-03] MRI strainによる無症候性術後ファロー四徴症の肺動脈弁置換至適タイミングの検討
キーワード：feature tracking MRI, RV myocardial mechanics, repaired tetralogy of Fallot
Objective: To consider optimal timing for pulmonary valve replacement (PVR) in asymptomatic repaired tetralogy of Fallot (TOF) using feature tracking (FT) MRI.
Methods: 50 repaired TOF patients were divided into two groups, right ventricular end-diastolic volume (RVEDV) exceeding 160 ml/m2 (group A, n=25) and the group not exceeding 160 ml/m2 (group B, n=25). Novel software was used to perform global longitudinal strain (GLS) and strain rate (GLSR) and global circumferential strain (GCS) and strain rate (GCSR), and wall motion delay (WMD) between RV free wall and septal wall.
Results: Mean age of group A was 27.1±7.9 years and 31.4±14.2 years in group B. In both groups, GLS and GLSR were declining, but GCS and GCSR were preserved (p＜0.01) in group B. All strain values correlated with increasing RVEDV (r=0.45 to 0.79) and end-systolic volume (RVESV) (r=0.5 to 0.82), and decreasing RV ejection fraction (r=-0.36 to -0.77) in group A. In particular, the correlation of GCSR is high in group A (r=0.82). For WMD, group A was later than group B (p＜0.05). No relationship was found between strain value and pulmonary regurgitant fraction （PRF） in both groups.
Conclusions: The correlations associated all strain values with RV volume and function without PRF. Preservation of the circumferential strain is important in maintaining RV function in group B. The optimal timing for PVR is considered before RVEDV exceeds 160 ml/m2 in asymptomatic repaired TOF. RVESV should also be simultaneously considered in deciding. FT analysis may be a serial method to estimate RV myocardial mechanics.
Methods: 50 repaired TOF patients were divided into two groups, right ventricular end-diastolic volume (RVEDV) exceeding 160 ml/m2 (group A, n=25) and the group not exceeding 160 ml/m2 (group B, n=25). Novel software was used to perform global longitudinal strain (GLS) and strain rate (GLSR) and global circumferential strain (GCS) and strain rate (GCSR), and wall motion delay (WMD) between RV free wall and septal wall.
Results: Mean age of group A was 27.1±7.9 years and 31.4±14.2 years in group B. In both groups, GLS and GLSR were declining, but GCS and GCSR were preserved (p＜0.01) in group B. All strain values correlated with increasing RVEDV (r=0.45 to 0.79) and end-systolic volume (RVESV) (r=0.5 to 0.82), and decreasing RV ejection fraction (r=-0.36 to -0.77) in group A. In particular, the correlation of GCSR is high in group A (r=0.82). For WMD, group A was later than group B (p＜0.05). No relationship was found between strain value and pulmonary regurgitant fraction （PRF） in both groups.
Conclusions: The correlations associated all strain values with RV volume and function without PRF. Preservation of the circumferential strain is important in maintaining RV function in group B. The optimal timing for PVR is considered before RVEDV exceeds 160 ml/m2 in asymptomatic repaired TOF. RVESV should also be simultaneously considered in deciding. FT analysis may be a serial method to estimate RV myocardial mechanics.