Is there a correlation between late re-exploration after cardiac surgery and removal of epicardial pacemaker wires?

Re-explorations for acute bleeding or haematoma evacuation are relatively frequent after major cardiac procedures, especially as modern guidelines recommend operating patients on aspirin or even on DAPT, for example in coronary surgery [4]. Reopening of a sternotomy potentially complicates wound healing, prolonging hospital stay and elevating costs [5]. Removal of the temporary EPW can potentially complicate the postoperative course of a cardiac surgical patient through acute bleeding and pericardial tamponade, nevertheless the exact incidence of this complication remains unclear, as there is a sparsity of data published in the literature.

Use of temporary epicardial pacemaker wires to manage possible complications, as bradycardia, postoperative atrial fibrillation with need for cardiac defibrillation or atrioventricular block, is a common procedure in cardiac surgery [1]. Although need of EPW can be questioned in selected cases, i.e. low-risk aortic valve replacement [6–8], presence of these wires can be very helpful in weaning from cardiopulmonary bypass or improving cardiac output in the early postoperative period [9].

At our department, EPW are sutured on the right atrium and right ventricle in every patient, except in presence of atrial fibrillation, where the atrial wire is omitted. We use a single type of temporary epicardial wires over the last years. Implantation of this type of wires does not necessitate any extra stitches.

The timing of EPW removal depends on the need for pacing postoperatively. These temporary wires are normally removed on the 4^th to 5^th POD by stable cardiac rhythm or later in cases where a cardioversion due to persistent postoperative atrial fibrillation is needed or a transient atrioventricular block demands pacing. Coagulation screening is made by every patient who is on VKA or high-dose unfractionated heparin before removing of these temporary wires, in order to prevent bleeding.

Several serious and somewhat bizarre complications after removal of EPW have been described in the literature [10–13]. Mahon et al. mention a less than 1% need for re-exploration due to pericardial tamponade after removal of EPW in a retrospective study involving more than 23000 patients with cardiac surgery [3]. These data coincide with our findings, showing eight patients with pericardial tamponade, where removal of EPW was the definite cause of bleeding (incidence 0.18%). Defining removal of the EPW as the cause of bleeding was somewhat arduous as an active bleeding from the insertion site of the wires was found and needed to be surgically managed in only two of the eight patients. In the remaining six patients, echocardiography was normal before removal of the wires, whereas the clinical symptoms directly after taking out the wires were characteristic of a pericardial tamponade. Whether a late removal of the EPW can result in pericardial bleeding, it remains totally unclear.

Our patients were managed either with re-exploration through repeat sternotomy or with the insertion of a subxiphoid pericardial drainage. Unfortunately, the outcome was fatal in two cases (2 of 8), whereas need for blood transfusion and wound infection due to resternotomy complicated three of the remaining 6 patients. These data support the finding that pericardial tamponade after removal of the EPW increases both morbidity and mortality.

In addition, our database revealed six more cases with a late re-exploration after the 14 POD. All of these patients had been discharged from the hospital without any evidence of a significant pericardial effusion in the echocardiographic study, with the EPW being removed after echocardiography. Three of these patients, which were on VKA, had a documented serious derailment of INR during their rehabilitation. By the re-exploration of these patients, no definite cause of bleeding could be verified.

After studying of these data, we modified the standard procedure of removal of the EPW at our department. In order to minimize the risk of serious bleeding, we initiate the oral anticoagulation regimen – VKA or NOAC – after the EPW have been taken out. Although none of the eight patients were on NOACs, we believe that it is prudent to commence these regimens after pulling out the EPW, as no standard screening for NOACs is routinely used [14]. On the other hand, patients who have a strong indication for DAPT, for example by coronary intervention with drug eluting stent implantation in the short-time perioperative period, still have their EPW removed under this medication. Whether it is rational to commence with the second antiplatelet agent after taking out the wires, it is dependent upon the indication for DAPT. Furthermore, we recommend that a high-dosed LMWH should be avoided 12 h before removal of EPW, and that intravenous administration of heparin should be paused for at least 3–4 h. Finally, performing the echocardiographic study after removal of the EPW, although a standard procedure by paediatric patients at our department is probably unrealistic as it is time-consuming and costly and even detection of some pericardial effusion may not prevent tamponade at a later time. Nevertheless, pre-removal echocardiography may detect a pericardial effusion that is clinically not apparent, but potentially aggravated by the EPW removal.