Impact of atrial fibrillation on clinical outcomes in 28,492 patients following open-heart cardiac valve surgery: A statewide population-linkage study.

Abstract

Atrial fibrillation (AF) is common after cardiac surgery. Few studies compared clinical outcomes associated with AF between patients undergoing aortic valve surgery (AVSx) versus mitral valve surgery (MVSx). Patients who had open-heart cardiac valve surgery (1- July-2003 to 31-March-2021) identified from the Admitted-Patient-Data-Collection database in Australia were stratified by AF status (No-AF vs. New-AF vs. Prior-AF during index valve surgery) and followed up to 31-March-2022. Multivariable Cox regression and Fine-Gray competing risk analyses were performed to assess the association of AF status on all-cause mortality and non-fatal outcomes respectively. The cohort comprised 28,492 patients (whole cohort median age 71.6yrs [interquartile range 62.7-78.3yrs]; 65.6% males): AVSx, n = 18,949, median age 73.3 [IR 65.4-79.4yrs], 67.8% males; MVSx, n = 9543, MVSx: median age 67.6 [IR 58.2-75.5yrs], 61.2% males. During a median 6.58yrs (3.4-10.5yrs) follow-up, Prior-AF and New-AF patients had significantly higher all-cause mortality (AVSx-Prior-AF: 57.9% vs. AVSx-New-AF: 41.5% vs. AVSx-No-AF: 32.8%; MVSx-Prior-AF: 41.0% vs. MVSx-New-AF: 29.8% vs. MVSx-No-AF: 22.4%) (both logrank P < 0.001). In the AVSx subgroup, both New-AF and Prior-AF were independently associated with all-cause mortality (aHR = 1.16, 95%CI = 1.10-1.22; aHR = 1.69, 95%CI = 1.59-1.79 respectively) compared to No-AF patients. In the MVSx subgroup, only Prior-AF was associated with increased all-cause mortality (aHR = 1.47, 95% CI = 1.33-1.61), all P < 0.001. Ischaemic stroke was significantly higher in the AVSx New-AF and AVSx-Prior-AF subgroups. Patients undergoing valve surgery have different risks of adverse clinical outcomes, with target valve and baseline AF status being associated with these outcomes.