Abstract 1980: The Impact of Diastolic Function on Quantifying Pulmonary Regurgitation After Tetralogy of Fallot Repair: Reappraising Regurgitant Fraction and Regurgitant Volume
Purpose: Right ventricular (RV) cavity dilation and dysfunction are well-recognized late sequelae of pulmonic regurgitation (PR) after repair of tetralogy of Fallot (TOF). Previous investigators have suggested that regurgitant fraction (PRfract) and volume (PRvol) are not interchangeable measures of PR severity. We sought to assess the effect of RV diastolic physiology on quantifying PRfract and PRvol.
Methods: Consecutive patients (n=59, mean age 29±13 yrs, 54% female) with PR after TOF repair undergoing cardiac magnetic resonance imaging (MRI) were identified. Restrictive diastolic physiology was identified by antegrade diastolic flow (a-wave) assessed by pulsed-wave Doppler echocardiography within the main pulmonary artery (MPA). PR was quantified from velocity encoded phase contrast MRI of the MPA and expressed as a volume (PRvol) and percentage of total forward flow (PRfract). Ventricular volumes were assessed by modified Simpson’s rule from short axis steady-state free precession images.
Results: The median indexed PRvol was 23ml/m2 (IQR 16 –37) and indexed RVEDV was 151ml/m2 (IQR 126 –172) in the entire study population. Non-restrictive diastolic physiology was identified in 47 subjects (80%). Both PRvol and PRfract had discriminatory power to distinguish moderate from mild, and severe from moderate RV cavity dilation (figure⇓) in the non-restrictive group. This discrimination could not be replicated for indexed PRvol or PRfract in the group of 12 patients with restrictive physiology (p=NS).
Conclusion: Indexed PRvol and PRfract are valid parameters to distinguish mild, moderate and severe PR in the absence of restrictive physiology.