Posterior left pericardiotomy safe and effective in reducing atrial fibrillation

Posterior left pericardiotomy significantly reduced the incidence of post-operative atrial fibrillation (AF) after cardiac surgery and appeared safe in the PALACS trial [1].

Post-operative AF is the most common complication of cardiac surgery, with an incidence of 20–40%, depending on the performed surgery [2]. The incidence of post-operative pericardial effusion is also common, with an incidence of 60–70% [3]. Dr Mario Gaudino (Weill Cornell Medical Center, NY, USA), first author of the PALACS trial (NCT02875405), argued there is evidence that post-operative pericardial effusion is associated with post-operative AF [1,4].

The PALACS study hypothesised that a 4 to 5 cm incision in the posterior pericardium, connected to the left pleural cavity, allows for drainage and, thus, reduces post-operative AF. Patients (n=420) undergoing cardiac surgery (i.e. coronary arteries, aortic valve, and/or ascending aorta) were randomised 1:1 to posterior left pericardiotomy or no additional intervention. The primary outcome was in-hospital post-operative AF, assessed by cardiac rhythm monitoring.

Participants in the pericardiotomy arm had fewer post-operative AF events (18%) than patients in the no-intervention arm (32%; RR 0.55; P<0.001). The cumulative time in AF was 1,262 hours in the intervention arm versus 2,277 hours in the no-intervention arm. In addition, the results displayed a reduction in the need for post-operative antiarrhythmic medications (RR 0.55) and systemic anticoagulation (RR 0.44) in the intervention arm. A subgroup analysis showed consistency of the primary outcome across predefined strata such as demographic and surgery type. The safety data showed that postoperative pericardial effusion was more prevalent in the no-intervention arm (21%) than in the intervention arm (12%; RR 0.58; CI 95% 0.37–0.91). Rates of operative mortality (1% in both groups), postoperative major adverse events (2% and 3%), and postoperative left pleural effusion (30% and 32%) were comparable.

The current trial had many strengths. This is the first surgical approach to reduce post-operative AF after cardiac surgery. Moreover, the hypothesis that post-operative AF is secondary to pericardial effusion-induced inflammation is novel. Compared with other available options to reduce post-operative AF following cardiac surgery, such as pre-operative β-blocker, pre-operative amiodarone, colchicine, and intra-operative botulinum, the risk reduction of posterior pericardiotomy of approximately 45% is pronounced.

However, this trial only investigated in-hospital post-operative AF. Possible events of sub-acute AF were not captured. The study did also not include patients who were scheduled for mitral valve or tricuspid valve surgery. In addition, the absolute reduction should be interpreted in the context of the sample size and additional data will clarify the absolute and durability of effect. Although Dr Gaudino argued that there is no biologic rationale to expect a different result in these patients, it should be examined in future trials. Following these encouraging results, the next step would be to test posterior left pericardiotomy in a large, multicentre trial across the entire spectrum of cardiac surgery.

1. 
   
   1. Gaudino M, et al. Posterior left pericardiotomy for the prevention of atrial fibrillation after cardiac surgery: an adaptive, single-centre, single-blind randomised controlled trial. LBS03, AHA 2021 Virtual Congress, 13–15 November.
   2. Greenberg JW, et al. Eur J Cardiothorac Surg. 2017;52(4):665–672.
   3. Pepi M, et al. Br Heart J. 1994;72(4):327–331.
   4. St-Onge S, et al. Ann Thorac Surg. 2018;105(1):321–328.

 

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Posted on 14 January 202218 January 2022