Temporary epicardial pacing wires are routinely inserted after cardiac surgery (AlWaqfi et al, 2014) as postoperative arrhythmias are frequent in the cardiac surgery setting. The most frequently observed postoperative arrhythmias are supraventricular tachyarrhythmias, especially atrial fibrillation. Bradyarrhythmias are also frequently observed after cardiac surgery, due to conduction system trauma (Peretto et al, 2014).
The safety and efficacy of epicardial pacing wires have been accepted (Mishra et al, 2010). They allow emergency or therapeutic pacing, if required, after surgery. They remain in place for 24 hours to several days following surgery and are used to maintain heart rate and rhythm, which are necessary to optimise haemodynamics (AlWaqfi et al, 2014). Epicardial wires are manufactured with a small needle on one end. This is used to embed the wire in the myocardium, after which the needle is cut off. A larger needle on the other end of the wire is used to penetrate the body wall, bringing the wire to the surface.
Wires may be placed in the atrium or ventricle. Although the right ventricle is the most common location for epicardial wire placement, there is no agreement on optimal wire position (Reade, 2007). One of the main reasons for insertion of ventricular epicardial pacing wires is complete atrioventricular block (Khorsandi et al, 2012).
Epicardial wires are not the only means of temporary pacing after cardiac surgery. Alternative methods include temporary transvenous pacing wires, transcutaneous electrodes or via an electrode attached to an oesophageal probe. However, if pacing is an anticipated requirement after cardiac surgery, epicardial wires are the preferred technique. They more reliably sustain capture and are less prone to dislodgement and infection than a temporary transvenous pacing wire. Furthermore, they do not require sedation, as is often the case for transcutaneous pacing or an oesophageal probe (Reade, 2007).
Although epicardial wire insertion appears to be standard intraoperative practice internationally, there are differences across centres with regard to the management of patients and their pacing wires afterwards. It is generally accepted that pacing wires should be removed when the patient is haemodynamically stable and non-reliant on the external pacemaker. However, there is limited literature available on this topic and there are no national or international guidelines on which to base best practice regarding use and removal of these wires.
Pacing wires are removed with gentle transcutaneous retraction (Mishra et al, 2010). After pacing wire removal, patients are at risk of arrythmias, haemorrhage and tamponade from atrial and ventricular lacerations, injury to saphenous vein graft and remnant wire retention (Johnson et al, 1993). Because of the risk of complications following wire removal, patients are generally not discharged from hospital until 24 hours after the procedure. In the UK, epicardial wires are usually removed on day 4, with patients discharged on postoperative day 5 (McNaughton, 2013). Some authors suggest that wire removal takes place on or after postoperative day 3 (Mahon et al, 2012), while others provide a broader scope of 2-5 days after surgery for wire removal (Marolda and Finkelmeier, 2000). A Canada-wide survey found that there was great variation across the cardiac centres that were surveyed with regard to the management of pacing wires following cardiac surgery (Frew, 2016).
Aim and objective
The aim of this study was to evaluate the insertion, use, duration and complications of epicardial pacing wires following cardiac surgery in a cohort of patients in Ireland. The overall aim of the study was to evaluate practice, make recommendations for change if necessary, and to initiate discourse on the need for standardisation of practice across cardiac centres in Ireland and beyond.
Methods
The study measured the number of patients in whom pacing wires were inserted and their associated surgery, together with their postoperative pacing requirements, the duration of pacing wire placement and length of hospitalisation for each patient. The authors also measured whether there were complications associated with wire removal.
Study design
This was a non-experimental cross-sectional study. Data were collected in 2017 in an Irish hospital. The investigation conformed to the principles outlined in the Declaration of Helsinki and the study was approved by the hospital's ethics review board. As data were anonymised and no personal data were collected, the hospital ethics committee did not request patient consent for this study.
Setting and sample
The sample in this study comprised all patients, regardless of age, who were admitted to the research centre for a cardiac surgical procedure (both elective and emergency). The inclusion criterion was the insertion of epicardial pacing wires at the end of the operation. There were no exclusion criteria.
Data collection
Using non-probability consecutive sampling, data were collected prospectively over a 5-month period. A bespoke data collection sheet was designed for the study purpose. Content and face validity of the instrument was evaluated by two cardiothoracic surgeons, one advanced nurse practitioner, an experienced nurse whose background was in database maintenance and two academics. All data were recorded prospectively by a researcher. The data, which were all objective, were recorded directly onto the data collection sheet: age, gender, patient history, ejection fraction from preoperative echocardiogram, pre- and postoperative heart rate, in addition to information on pacing, including type of wire inserted (atrial, ventricular), mode, rate and wire use each day following surgery. Detailed information was also recorded on the time pacing wires remained in situ, the day of wire removal and complications associated with their removal.
The advanced nurse practitioner in the cardiothoracic theatres acted as study gatekeeper. She completed the data collection sheet for each patient at the time of surgery and in the subsequent days. The data collection instrument was piloted over 1 week, after which no changes were made. Data collection sheets were collected and entered onto a database weekly. All of the data were proofed and cleansed and missing data were confirmed or clarified by returning to the patients' medical notes. Categorical data were summarised by using frequencies and percentages. Data were analysed using SPSS v23.
Results
To contextualise the study, 167 patients were admitted for cardiac surgery during the data-collection period, the majority of whom were emergency cases (74%, n=121). Epicardial pacing wires were inserted in 98% of patients (164/167). Three patients did not have epicardial pacing wires inserted at the end of the procedure, two had ventricular repairs secondary to stab injury, the third had a pericardial window. In this study, all patients who had either coronary artery bypass grafting (CABG) or valve surgery during the period of data collection had epicardial pacing wires inserted. In total, 86% (n=141) had ventricular wires only inserted, while 5% (n=8) had atrial wires only. A further 9% (n=15) had both atrial and ventricular wires inserted. The majority of the sample was male (n=136). Age was recorded as a categorical variable and ranged from 40 years to 79 years. Most (48%) fell within the 70-79 age category, while one-third were in the 60-69 age category.
Pacing set rates were recorded and these varied, based on patients' haemodynamic stability. It was noted that while surgeons always checked the wires were working before leaving theatre, they often turned the pacing box off, as the patient was stable with their own intrinsic rhythm. Despite patient stability, anaesthetic staff tended to set the pacing box to a low-level rate (40-50 beats/minute) for postoperative transfer to the intensive care unit. These low pacing rates were then left on until the first morning after surgery (morning of postoperative day 1).
Bradyarrhythmias are particularly common after valve surgery and are a consequence of direct surgical injury and local oedema (Peretto et al, 2014). Evidence shows that patients at high risk for requiring permanent pacemaker implantation after heart surgery include those with pre-existing conduction disturbances and those undergoing aortic valve replacement (AVR) (Merin et al, 2009). Therefore, the authors categorised the sample into those who had AVR (n=42) and those who had cardiac surgery that did not involve AVR (n=122). The breakdown of these groups can be seen in Table 1 and Table 2.
| Aortic valve replacement surgery (N=42) | |
|---|---|
| AVR | 29 |
| AVR and CABG | 9 |
| AVR and MVR | 1 |
| AVR, MVR and CABG | 1 |
| AVR and ascending aorta replacement | 1 |
| AVR and CABG | 1 |
AVR=aortic valve replacement; CABG=coronary artery bypass graft; MVR=mitral valve replacement
| Surgery other than aortic valve replacement (N=122) | |
|---|---|
| MV repair (3 with TVR, 2 with CABG) | 12 |
| MVR (2 with TVR) | 8 |
| CABG | 98 |
| CABG and TVRp | 1 |
| CABG and ascending aorta replacement | 1 |
| CABG and myxoma | 1 |
| Pericardectomy | 1 |
CABG=coronary artery bypass graft; MV=mitral valve; MVR=mitral valve replacement; TVR=tricuspid valve replacement; TVRp=tricuspid valve repair
Of the 42 patients in the AVR group, 26% (n=11) required their pacing wires after surgery, and 10% (n=4) of the 42 patients required permanent pacemakers.
Of the 122 patients in the non-AVR group, 25% (n=30) required temporary pacing, of whom most (n=18) were paced for less than 12 hours. Two patients from the non-AVR group required permanent pacemaker insertions; both had undergone tricuspid valve replacement (Table 3 and Table 4).
| Required postoperative pacing (n, %) | 11 (26%) |
|---|---|
| Paced for <12 hours | 3 (7%) |
| Paced for 1 day | 3 (7%) |
| Paced for 2 days | 0 |
| Paced for 3 days | 1 (2%) |
| Paced for 4 days | 0 |
| Paced for ≥ 7 days | 4 (10%) |
| Required permanent pacemaker | 4 (10%) |
| Required postoperative pacing (n, %) | 30 (25%) |
|---|---|
| Paced for <12 hours | 18 (15%) |
| Paced for 1 day | 2 (2%) |
| Paced for 2 days | 4 (3%) |
| Paced for 3 days | 0 |
| Paced for 4 days | 4 (3%) |
| Paced for ≥ 7 days | 2 (2%) |
| Required permanent pacemaker | 2 (2%) |
More than half the sample (n=87, 53%) had pacing wires removed by day 4, while 18% (n=29) had them removed on day 5. The remainder (n=44, 27%) had wires removed after day 6, except for a small number of patients who died with pacing wires in situ (n=4; 2%). The causes of death were cardiac arrest due to pulseless electrical activity (1), ventricular tachycardia (1) and asystole (2). Others (n=3; 2%) had delayed removal of pacing wires because of anticoagulation issues (Table 5).
| Postoperative day of wire removal | n, % |
|---|---|
| Day 3 | 8 (5%) |
| Day 4 | 79 (48%) |
| Day 5 | 29 (18%) |
| Day 6 | 28 (17%) |
| Day 7 or more | 16 (10%) |
| Died with wires in situ | 4 (2%) |
There were 33 patients with valid, documented reasons for delayed wire removal (Table 6). The protocol at the research site is for unused pacing wires to be removed on postoperative day 4. So, for the majority, wire removal was in accordance with that policy. However, the policy also states that pacing wires are only removed during business hours. In this study, there were 40 patients (24%) whose fourth postoperative day was a weekend day, so their wires were not removed. In addition, there were four patients whose delay was unexplained.
| Reasons for non-removal of pacing wires on postoperative day 4 | Patients (n) |
|---|---|
| Reason for delay in wire removal documented (heart block, coagulation issues, bradycardia, pauses) | 29 |
| Delayed wire removal as day 4 was at a weekend | 40 |
| Died with wires in situ | 4 |
| No documented reason for non-removal of wires on day 4 | 4 |
Of the 40 patients whose fourth postoperative day was a weekend, 27 (17% of the 77 with delayed removal) had no other surgical or medical issues requiring hospitalisation and were discharged the day after wire removal. In this study, there were no complications associated with insertion, use or removal of wires. The only pacing wire-related complication was delayed discharge, which was an important finding.
Discussion
Epicardial pacing wires are inserted as a routine procedure in most patients after cardiac surgery (Lazarescu et al, 2014; Elmistekawy et al, 2016; Patris et al, 2016). This is understandable, given that patients are thought to be more susceptible to haemodynamic compromise and arrhythmias during the early postoperative period. However, the insertion of temporary epicardial pacing wires dates back to the 1960s and although cardiac surgery has been through extensive changes since that time, the trend for inserting pacing wires has failed to keep pace with these changes (AlWaqfi et al, 2014). Studies suggest that wires are routinely inserted in two-thirds of cases (Srivastava et al, 2015), although accurate figures are difficult to determine, owing to variation between the type of surgery, surgeons' preferences and regional differences. In this study, 98% of patients had wires inserted as a routine procedure.
Although limited, there is evidence from the literature that some cardiac surgeons are selective about wire insertion (Gupta et al, 2012; AlWaqfi et al, 2014). This is something that might be more widely adopted, for example, in the case of low-risk valve replacement (Imren et al, 2008; AlWaqfi et al, 2014). The suggestion of selective consideration of the need for pacing wires is supported by the results here, where only 26% of the AVR and 23% of the non-AVR group required pacing, thereby suggesting that around three-quarters of the time, valve replacement patients do not need or use pacing wires. It is of note that although the authors categorised the cohort of patients into AVR and non-AVR groups, the two patients in the non-AVR group who required permanent pacemaker insertion both had tricuspid valve surgery. Evidence suggests that permanent pacing may be required in 20–24% of patients after some types of surgery, such as for calcific aortic stenosis or tricuspid valve repair (Peretto et al, 2014), suggesting a need for careful, individualised patient selection for pacing wire insertion.
For patients with pacing wires in situ, the day of their removal is undetermined from the literature and there are no internationally accepted guidelines on the optimum postoperative day for wire removal. In keeping with local protocol, most epicardial pacing wires were removed on the fourth postoperative day in this study, which is consistent with other centres (McNaughton, 2013; Patris et al, 2016; Bougioukas et al, 2017). However, for 47% (n=77) of the sample in this study, pacing wires were in situ beyond day 4 because the unit policy mandated pacing wire removal during business hours only. In this research site, there is only one cardiac surgery registrar on call out of hours, so this policy is in place to ensure patient safety. As complications can occur following epicardial pacing wire removal, adequately qualified staff should be available to deal with post-wire removal emergencies outside business hours.
The restriction of wire removal to business hours is not unique to Ireland. In a survey of 126 UK-based cardiothoracic surgeons, 70% would not remove pacing wires outside daytime hours (Srivastava et al, 2015). However, unlike the study here, 54% of surgeons surveyed by Srivastava et al (2015) removed them over weekends and public holidays.
Patients generally remain in hospital for a time after wire removal to observe for associated complications—mainly cardiac tamponade (Mahon et al, 2012; Elmistekawy et al, 2016). However, the duration of observation is neither evidence-based nor defined. In this study, patients remained in hospital for an observation period of 24 hours, while in other cardiac surgery centres, patients were discharged, if haemodynamically stable, following a 4-hour observation period (Srivastava et al, 2015; Elmistekawy et al, 2016). It is worth noting that not all patients who develop cardiac tamponade as a complication of wire removal would be picked up within 4 hours of wire removal (Mahon et al, 2012). This suggests that further study is required to determine and standardise the appropriate observation period and the optimum discharge time.
In this study, there were no direct complications associated with wire removal. However, the results suggests that 27 patient discharges were delayed because epicardial pacing wires were not removed over weekends. These patients may have been discharged up to 2 days earlier if their unused pacing wires had been removed on schedule on the fourth postoperative day. There was no other documented reason for these patients to remain in hospital. Although delayed discharge is not a direct pacing wire complication per se, wire removal was linked with discharge time, which has negative implications for patients, their carers, hospital staff and healthcare resources (Rojas-García et al, 2018). Studies have shown that delayed discharge increases the risk of mortality, increases the propensity to contract one or more infections (Jasinarachchi et al, 2009; Rosman et al, 2015) and is linked with a reduced capacity to perform one's activities of daily living (Young and Green, 2010; Rojas-García et al, 2018).
From a financial perspective, in Ireland, over the 3 years of 2014, 2015 and 2016, the Department of Health and Children spent over a quarter of a billion Euros in efforts to relieve delayed discharges and pressure on waiting lists (Duff, 2017) and it is acknowledged that bed capacity is strained by large numbers of delayed discharges and deficits in critical care capacity (Health Service Executive National Integrated Care Advisory Group, 2014; Health Service Executive, 2018). Estimates suggest that in England delayed discharges cost something in the region of £100 million each year (Gaughan et al, 2017; Rojas-García et al, 2018). These figures are noteworthy in the current climate of limited resources and value-improvement initiatives. In this study, there was potential for an additional 27 patients to be discharged 1-2 days earlier, if their pacing wires were removed sooner. These additional bed days could be recouped through the revision and refinement of policies on the removal of pacing wires and if greater consideration were given to selecting and separating low-, medium- and high-risk patients, in terms of their need for use of pacing wires, as opposed to routinely inserting them in all eligible patients. The benefits of timely discharge are well documented and include better healthcare experiences for patients, improved health outcomes and greater satisfaction for health service providers, together with improved efficiency of service provision and management (Health Service Executive National Integrated Care Advisory Group, 2014).
Based on the outcomes of this study, practice has been changed in the cardiothoracic unit. Consistent with the recommendations from this study, pacing wire requirements are reviewed daily and for some patients who have no contraindications to their removal, including no evidence of their need, they may now be removed before the weekend. For some patients, the wire removal might be on the second or third postoperative day. This facilitates discharges over the weekend, thereby benefitting the patient and staff, while also responding to broader health service requirements.
Conclusion
This study was undertaken to establish the use, duration and complications of epicardial pacing wires following cardiac surgery, with a view to making recommendations and standardising practice. Most patients in this study did not require postoperative pacing. Because local policy stipulated that epicardial pacing wires were removed only during business hours, 47% of patients had pacing wires in place beyond the fourth postoperative day, which was the standard day for wire removal in uncomplicated cases. Consequently, delayed wire removal was linked with delayed discharge, which has physical, psychological and financial consequences. These patients had no other pacing wire complications. Based on the outcomes of this study, changes have been introduced in the research centre. One such change is the implementation of a case-by-case evaluation of each patient's pacing wire needs. If there are no contraindications, pacing wires are now removed before the fourth postoperative day. There have been changes to the documentation of pacing procedures, resulting in greater clarity regarding rate settings. Although placement of epicardial pacing wires remains at the discretion of the cardiac surgeon, the change to removing unneeded pacing wires before postoperative day 4 has now become accepted practice in this hospital. This procedure is currently being re-audited, so that the effects of this study can be fully evaluated.
Given the results of the study and the changes that have arisen from it, there is a requirement to review practices nationally and internationally. Further research is necessary to answer outstanding questions, such as the category of patient who is likely to require pacing, the optimum timing for removal of pacing wires and the most suitable day of discharge following wire removal. Furthermore, cohesive action is needed to challenge traditional practices and to promote evidence-based practice with regard to selective wire insertion in low-risk surgical patients.