Postoperative pericardial effusion, pericardiotomy, and atrial fibrillation: an explanatory analysis of the PALACS trial

Rong, L.Q.; Franco, A. di; Rahouma, M.; Dimagli, A.; Chan, J.; Lopes, A.J.; ... ; Gaudino, M. (2023)

Article / Letter to editor

Background

In the Posterior left pericardiotomy for the prevention of atrial fibrillation after cardiac surgery (PALACS) trial, posterior pericardiotomy was associated with a significant reduction in postoperative atrial fibrillation (POAF) after cardiac surgery. We aimed to investigate the mechanisms underlying this effect.

Methods

We included PALACS patients with available echocardiographic data (n = 387/420, 92%). We tested the hypotheses that the reduction in POAF with the intervention was associated with 1) a reduction in postoperative pericardial effusion and/or 2) an effect on left atrial size and function. Spline and multivariable logistic regression analyses were used.

Results

Most patients (n = 307, 79%) had postoperative pericardial effusions (anterior 68%, postero-lateral 51.9%). The incidence of postero-lateral effusion was significantly lower in patients undergoing pericardiotomy (37% vs 67%; P < .001). The median size of anterior effusion was comparable between patients with and without POAF (5.0 [IQR 3.0–7.0] vs 5.0 [IQR 3.0–7.5] mm; P = .42), but there was a nonsignificant trend towards larger postero-lateral effusion in the POAF group (5.0 [IQR 3.0–9.0] vs 4.0 [IQR 3.0–6.4] mm; P = .06). There was a non-linear association between postero-lateral effusion and POAF at a cut-off at 10 mm (OR 2.70; 95% CI 1.13, 6.47; P = .03) that was confirmed in multivariable analysis (OR 3.5, 95% CI 1.17, 10.58; P = 0.02). Left atrial dimension and function did not change significantly after posterior pericardiotomy.

Conclusions

Reduction in postero-lateral pericardial effusion is a plausible mechanism for the effect of posterior pericardiotomy in reducing POAF. Measures to reduce postoperative pericardial effusion are a promising approach to prevent POAF.

Graphical abstract

Pathophysiological mechanisms explaining the association between postoperative pericardial effusion and the occurrence of postoperative atrial fibrillation. Hb, hemoglobin; MetHb, methemoglobin; OxyHb, oxyhemoglobin; ROS, reactive oxygen species.

• All authors: Rong, L.Q.; Franco, A. di; Rahouma, M.; Dimagli, A.; Chan, J.; Lopes, A.J.; Kim, J.; Sanna, T.; Devereux, R.B.; Delgado, V.; Weinsaft, J.W.; Crea, F.; Alexander, J.H.; Gillinov, M.; Dimaio, J.M.; Pryor, K.O.; Girardi, L.; Gaudino, M.
• Date: 2023-04-05
• Journal: American Heart Journal
• Volume: 260
• Pages: 113 - 123
• DOI: doi:10.1016/j.ahj.2023.03.001
• Link: https://www.sciencedirect.com/science/article/pii/S0002870323000637?via%...