Right Ventricular Strain in Patients With Ductal-Dependent Tetralogy of Fallot

Background: Right ventricular (RV) dysfunction is an independent predictor of poor outcomes in patients with tetralogy of Fallot (TOF), and global longitudinal strain (GLS) is a well-validated echocardiographic technique to measure RV function. Although trends in RV GLS have been examined in patients with TOF, they have not been studied specifically in those with ductal-dependent TOF, a group in which there is not a clear consensus on the best surgical strategy. The aim of this study was to assess the midterm trajectory of RV GLS in patients with ductal-dependent TOF, drivers of this trajectory, and differences in RV GLS between repair strategies.Methods: This was a retrospective two-center cohort study of patients with ductal-dependent TOF who underwent repair. Ductal dependence was defined as being initiated on prostaglandin therapy and/or under-going surgical intervention on or before 30 days of life. RV GLS was measured on echocardiography preop-eratively, early after complete repair, and at 1 and 2 years of age. RV GLS was trended over time and compared between surgical strategies and with control subjects. Mixed-effects linear regression models were used to evaluate the factors associated with changes in RV GLS over time.Results: Forty-four patients with ductal-dependent TOF were included in the study, of whom 33 (75%) under-went primary complete repair and 11 (25%) underwent staged repair. Complete TOF repair was performed at a median of 7 days in the primary-repair group and 178 days in the staged-repair group. RV GLS improved over time from post-complete repair echocardiography through 2 years of age (-17.4% [interquartile range,-15.5% to-18.9%] vs-21.5% [interquartile range,-18.0% to-23.3%], P < .001). However, compared with age-matched control subjects, patients had worse RV GLS at all time points. There was no difference in RV GLS between the staged and primary complete repair groups at 2-year follow-up. Shorter intensive care unit length of stay after complete repair was independently associated with improvement in RV GLS over time. Strain improved by 0.07% (95% CI, 0.01 to 0.12) for each fewer day in the intensive care unit (P = .03).Conclusions: RV GLS improves over time among patients with ductal-dependent TOF, though it is consistently reduced compared with control subjects, suggesting an altered deformation pattern in patients with ductal-dependent TOF. There was no difference in RV GLS between the primary-and staged-repair groups at midterm follow-up, suggesting that repair strategy is not a risk factor for worse RV strain in the mid postoper-ative period. A shorter complete-repair intensive care unit length of stay is associated with an improved trajectory of RV GLS. (J Am Soc Echocardiogr 2023;36:654-65.)

Automated summary

This study aimed to assess the mid-term trajectory of right ventricular global longitudinal strain (RV GLS) in patients with ductal-dependent tetralogy of Fallot (TOF). The results showed that RV GLS improved over time but remained worse compared to control subjects. There was no difference in RV GLS between different repair strategies, and a shorter intensive care unit length of stay after complete repair was associated with improved RV GLS trajectory.