Intracardiac Flow Analysis of the Right Ventricle in Pediatric Patients with Repaired Tetralogy of Fallot, using a novel Color-Doppler Velocity Reconstruction
Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography
BACKGROUND: Repaired Tetralogy of Fallot (RTOF) patients will develop right ventricular (RV) dysfunction from chronic pulmonary insufficiency (PR). Cardiac magnetic resonance (CMR) sequences such as 4D flow can demonstrate altered vorticity and flow energy loss (FEL), however they are not as available as conventional echocardiography (echo). The study determined whether a novel, vendor-independent Doppler Velocity Reconstruction (DoVeR) could measure RV intracardiac flow in conventional echo of RTOF patients. The primary hypothesis was that DoVeR could detect increased vorticity and diastolic FEL in RTOF patients. METHODS: RTOF patients with echo were retrospectively paired with age/size matched controls. DoVeR employed the streamfunction-vorticity equation to approximate intracardiac flow fields from color Doppler. A velocity field of RV was reconstructed from apical 4-chamber. Vortex strength (VS, area integral of vorticity) and FEL were derived from DoVeR. CMR and exercise stress parameters (performed within 1 year of echo) were collected for analysis. RESULTS: 20 RTOF patients and age-matched controls were included in the study. Mean regurgitant fraction was 40.5±7.6% and indexed RV end-diastolic volume was 158±36 mL/m. RTOF patients had higher total, mean diastolic and peak diastolic VS (p=0.0013, p=0.0012, p=0.0032, respectively) and higher total, mean diastolic and peak diastolic BSA-indexed FEL (p=0.0016, p=0.0022, p<0.001, respectively). Peak diastolic FELi and peak diastolic VS had weak-to-moderate negative correlation with RV ejection fraction (r=-0.52 [p= 0.019] and r=-0.49 [p =0.030], respectively) and left ventricular ejection fraction (r=-0.47 [p=0.034] and r=-0.64 [p = 0.002], respectively). Mean diastolic FELi and VS had moderate-to-strong negative correlation with %predicted maximal oxygen consumption (r=-0.69 [p=0.012] and r=-0.75 [p=0.006], respectively). CONCLUSIONS: DoVeR can detect alterations to intracardiac flow in RTOF patients from conventional color Doppler imaging. Echo-based measures of diastolic VS and FEL correlated with ventricular function. DoVeR has the potential to provide serial evaluation of abnormal flow dynamics in RTOF patients.
Meyers, Brett; Nyce, Jonathan; Zhang, Jiacheng; Frank, Lowell; Balaras, Elias; Vlachos, Pavlos; and Loke, Yue-Hin, "Intracardiac Flow Analysis of the Right Ventricle in Pediatric Patients with Repaired Tetralogy of Fallot, using a novel Color-Doppler Velocity Reconstruction" (2023). GW Authored Works. Paper 2373.