Pulmonary Valve Replacement-Related Change in Biventricular Global Function Index in Repaired Tetralogy of Fallot

Reduced biventricular global function index (BVGFI) is associated with adverse outcomes in repaired tetralogy of Fallot (rTOF). The change in BVGFI associated with pulmonary valve replacement (PVR) is unknown.

To characterize BVGFI following PVR in rTOF and identify pre-PVR factors associated with severely depressed post-PVR BVGFI.

Single-center retrospective cohort study of rTOF patients with a cardiac magnetic resonance (CMR) examination within 1 year before and 2 years after their first PVR and no interval cardiac procedures (n=133). CMR parameters between rTOF and normal controls (n=136) were compared. BVGFI was categorized as normal (≥46.2), mild-moderately depressed (40.0-46.1), or severely depressed (<40.0). Pre- vs. post-PVR changes and pre-PVR correlates of severely depressed post-PVR BVGFI were explored.

When adjusted for age and sex, pre-PVR BVGFI was lower in patients with rTOF compared to controls (47.7±0.6 vs. 56.0±0.5, p<0.001), with 48% of rTOF patients having subnormal pre-PVR BVGFI. Overall, compared with pre-PVR values, mean BVGFI did not change after PVR (46.6±7.7 vs. 45.6±6.7, p=0.28), while RVGFI declined from 49.6±10.2 pre-PVR to 46.1±9.0 post-PVR (p=0.003). Among patients with normal pre-PVR BVGFI (n=69), 64% remained normal, whereas 36% declined. Of those with severely depressed pre-PVR BVGFI (n=24), 50% remained severely depressed, and only 4% achieved normalization of BVGFI after PVR. Factors independently associated with severely depressed post-PVR BVGFI were lower pre-PVR BVGFI, male sex, moderate or severe pulmonary regurgitation (PR), and higher left ventricular end-systolic volume index (LVESVi). Type of pre-PVR hemodynamic load was not associated with the odds of severely depressed BVGFI post-PVR.

BVGFI is depressed in about half of rTOF patients pre-PVR and did not significantly change post-PVR remaining stable in most patients. Lower pre-PVR BVGFI, male sex, moderate or severe PR, and higher LVESVi are independently associated with severely depressed post-PVR BVGFI.