Prognostic value of left atrial strain in patients with Tetralogy of Fallot

PURPOSE: To demonstrate prognostic utility of left atrial strain(LAS) in adult patients with repaired Tetralogy of Fallot(rTOF). METHODS: Adults patients with rTOF were prospectively enrolled in this study between years 2011-2015. Left atrium(LA) phasic functions were assessed using 2D speckle tracking echocardiography(2D-STE). Association of LA strain(LAS) with primary(any cardiovascular event) and secondary(death, heart failure or arrhythmia) composite endpoints was assessed using Cox regression analysis. RESULTS: Hundred-and-twelve rTOF patients, in whom LAS was feasible and were in sinus rhythm, were included in the final analysis (age 33±10 years, 68[61%] male). Median duration of follow-up was 8.6[4.2-9.7] years in the study group. Primary composite endpoint was reached in 48 patients (mean event-free survival time: 7.2[6.6-7.9] years), and secondary composite endpoint was reached in 22 patients (mean event-free survival time: 8.7[8.1-9.2] years). LAS-r was defined as tertile groups(1 st tertile<33 %,2 nd tertile=33-44%,3 rd tertile>44%). Decreasing tertiles of LAS-r was associated with primary and secondary composite endpoints in Kaplan-Meier analysis(p=0.02 and 0.002, respectively). In univariable Cox-regression, both decreasing LAS-r and LAS-r tertiles were associated with primary and secondary composite endpoints. Adjusted by initial repair age and NT-proBNP quartiles, increased LAS-r was associated with significantly decreased occurrence of experiencing any events(HR=0.97,CI:0.93-0.99,p=0.037]). Decreasing LAS-r was still associated with primary endpoint when adjusted by left atrium volume index(LAVImax)(HR=0.96,CI:0.03-0.99,p=0.01),left ventricle global longitudinal strain(LV-GLS)(0.95,95%CI:0.92-0.98,p=0.002) or right ventricle free wall longitudinal strain (RV-FWLS)(0.96,95%CI:0.93-0.99,p=0.04). CONCLUSION: Assessment of LA mechanics with the use of STE has incremental utility in determination of mortality and morbidity in rTOF, and may be implemented in clinical practice.