The effect of a standardised protocol for CIED insertion on complications and infection rates in a DGH

Cardiac implantable electronic device (CIED)-related complications and infections typically lead to prolonged hospital stays and, very occasionally, death. A new CIED insertion protocol was implemented in a district general hospital. The primary objective of this study was to determine whether a significant reduction in complication and infection rates occurred after implementation of the new protocol. Medical records were reviewed for patients who had a CIED inserted in the two years pre- and post-protocol implementation, and any complications were identified in a one-year follow-up period.

An increase in the complexity of the devices implanted after introduction of the protocol was observed. The number of complications was significantly reduced from 6.86% to 3.95% (p<0.0001). In the two years prior to protocol implementation, 14 of 871 (1.6%) patients suffered a CIED-related infection. In contrast, four of 683 (0.44%) patients suffered a CIED-related infection in the two years post-implementation. This was not statistically significant (p=0.093).

In conclusion, implementing a standardised protocol for CIED insertion significantly reduced the rate of complications, and also reduced the rate of infection, but this was not statistically significant.

Introduction

There has been a steady increase in the number of cardiac implantable electronic devices (CIEDs) fitted in the UK over the last decade, and common complications of CIED insertion include bleeding or bruising at the insertion site, pneumothorax, lead displacement and infection.

Complications of device insertion are common. Some of the largest datasets come from Denmark. In 2013, an analysis of 5,918 consecutive cases found that 2.4% of patients required a lead-related re-intervention, 0.9% developed a pneumothorax, 0.8% developed infection, 0.6% had a cardiac perforation and 0.2% developed a haematoma requiring re-operation.¹ More recently, they have released data on infection in 97,750 consecutive patients and found a rate of infection of 0.82% in the first year after a procedure.²

Infection is a serious complication, which can result in death and prolonged hospital stays.³ There is concern that, due to the increasing complexity of device procedures and the increasing frailty of patients, infection rates are rising disproportionately.^2,4,5

This increase in infection is a problem both for the health of the patient and the additional costs to the National Health Service (NHS). Research has shown that implementation of a comprehensive infection control programme can be effective in reducing infection rate.^6,7

After an adverse outcome from a patient with a device-related infection at our centre, and a recognition that infection rates seemed unacceptably high, a new, comprehensive CIED standard operating procedure was constructed, with input from multiple departments within the trust, including infection control and microbiology, to try to reduce the number of CIED-related infections in our department. We hypothesised that these changes would reduce the rate of infection.

Method

The CIED standard operating procedure was implemented in August 2011 (table 1). A comprehensive list of patients who had undergone a CIED procedure within the cardiology department from August 2009 to July 2011 and August 2011 to July 2013 at Musgrove Park Hospital was collated. One year of follow-up after CIED insertion was chosen, as any infection after this point is not considered related to the CIED-insertion procedure.

All patients who underwent a procedure involving a ‘simple’ (single-chamber ventricular pacemaker [VVI], dual-chamber pacemaker [DDD], implantable-loop recorders [ILR]) or ‘complex’ pacing device (implantable cardioverter defibrillator [ICD], cardiac resynchronisation therapy with defibrillator [CRT-D] device, cardiac resynchronisation therapy with pacemaker [CRT-P]) were included. Whether or not it was a new procedure, a box change, a revision of an existing device or a procedure related to a complication was recorded. Data were acquired from yearly audit spreadsheets and an electronic implant database, which were then compared with the paper diaries kept by the catheter lab to ensure all procedures were documented. Operator details were also recorded where available.

Each patient’s paper and electronic medical records, including X-rays and discharge summaries, were reviewed to determine whether the patient had experienced any complications from their procedure. A complication was defined as any adverse event recorded within 12 months of the CIED insertion. The following complications were recorded:

• Infection requiring antibiotics and device removal or palliative care if not considered fit for device removal; superficial skin infections were not included
• Pneumothorax, whether or not a drain was required
• Haematoma requiring re-operation
• Lead displacement, whether or not requiring lead repositioning
• New pericardial effusion, whether or not requiring drain
• A ‘failed’ procedure – failure to implant a left ventricular (LV) lead
• Other significant complications – detailed.

The percentages of infection and complication rates were calculated for each group. Fisher’s exact test was used to test for significance. The relative risk was calculated to determine the risk of a patient from each group developing an infection and confidence intervals (CI) were then calculated.

Results

A total of 1,554 procedures took place over the four-year period. In 2009 to 2011 there were 871 procedures: 520 (59.7%) were male; 721 (82.8%) procedures involved ‘simple’ devices and 150 ‘complex’. A more complete breakdown of the procedures is shown in table 2. In 2011 to 2013 there were fewer procedures – 683: 429 (62.8%) were male; 506 (74.1%) procedures involved ‘simple’ devices and 177 ‘complex’. This increase in the proportion of complex devices was highly significant (p<0.0001).

There were 15 different operators in the pre-changes period, six of whom were consultants. There were nine different operators in the post-changes period, four of whom were consultants (table 3). Note that there was a small percentage (3%) of unknown operators in the 2009 to 2011 period due to missing data.

In the pre-changes group, 60 (6.9%) patients experienced a complication and 38 required a procedure to rectify a complication (4.4%). In the post-changes group, 27 (4.0%) experienced a complication and 18 required a procedure to rectify a complication (2.6%) (table 4). In both time periods, atrial lead displacement was the most common complication. In the pre-changes group, 14 (1.6%) patients had a CIED-related infection, which resulted in surgical removal of the device. In the post-changes group, there were four (0.6%) patients who had a CIED-related infection, which resulted in surgical removal of the device. This difference was not quite statistically significant (p=0.093).

Discussion

We introduced a standard operating procedure, including a surgical safety checklist, with the principal aim to reduce CIED-related infection. A reduction in infection rates was observed, but this was not quite statistically significant. Previous studies have found that implementation of a protocol to reduce CIED-related infection is effective.^9,12 This audit corroborates these earlier findings and provides further evidence that there is potential for national guidelines to have an effect on CIED-related infection rates. However, complication rates were reduced significantly; the overall rate of complications was reduced by over 40%. Surgical safety checklists have been shown to reduce complications.⁸

Prevention of complications is important at a time when the number of CIEDs being implanted is increasing. It impacts on patients, as many need further procedures, which is inefficient. Early re-intervention also increases infection risk.⁹ We believe that the reduction in complications occurred because of the constrained number of operators, increased surveillance of junior doctors and the introduction of a checklist.

Prior to this audit there were no fixed guidelines for CIED-related infection prevention at Musgrove Park Hospital, and nationally there were no set guidelines/protocols for CIED implantation. After the introduction of the new protocol there was a reduction in patients who contracted a CIED-related infection, this did not quite meet statistical significance. It is unclear what improved outcomes here. Previous research has shown operator experience reduces CIED-infection rates.⁵ There are little data on the most optimal prophylactic antibiotics, but pre-operative antibiotics appear effective.^10,11 The change to chlorhexidine skin preparation was driven by a trial suggesting it was more effective than povidone-iodine.¹² National Institute for Health and Care Excellence (NICE) clinical guideline 74 (now updated to NG125) was also referred to in the design of the new protocol.¹³

CIED-related infection significantly increases both admission and long-term mortality rates.¹⁴ This reduction in infection would result in a financial saving to the NHS, with 10 less patients over a two-year period potentially requiring further surgery and prolonged inpatient stays. The average cost of CIED-related infection in the UK is £30,958,⁷ and, therefore, a reduction of 10 patients with CIED-related infections over the two years would be a potential cost saving of £309,580. This would translate to a potential long-term saving to the NHS Trust of approximately £150,000 per annum.

Limitations and future directions

This research was carried out retrospectively, which, therefore, bears the inherent limitations of such studies, including patients who may have been lost to follow-up and errors in classification or recording. These limitations, and any bias, were minimised by including all procedures carried out within the time period and by using as many avenues as possible to follow-up the patients, including reviewing paper and electronic notes, device checks and X-ray imaging. Retrospective data collection limits the accessible data, so variables such as procedure time, for example, were not available, limiting the analysis of potential confounders.

The protocol implemented multiple changes in practice, therefore, it is not possible to determine which factors led to the reduction in complication rates, and which were most important. However, as the majority of changes implemented were fairly simple and low cost this should not be problematic, and the benefit of implementing the protocol would likely outweigh this disadvantage.

More recently, antibiotic envelopes have become available. The WRAP-IT (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial) study showed that for complex procedures, an antibiotic envelope could reduce the rate of infection (from 1.2% to 0.7%, p=0.04).¹⁵ Interestingly, just one more infection in the envelope group would have rendered the results non-significant (p=0.052). Whether this is cost-effective in the UK remains to be seen. In the US the base-case incremental cost-effectiveness ratio of the antibacterial envelope compared with standard-of-care was $112,603 per quality-adjusted life year,¹⁶ above the threshold typically set by NICE.

Finally, as this research was undertaken in a single-centre district general hospital, generalising conclusions from these findings across all centres would not be appropriate. We hope that a national audit, as takes place in some countries, would give a better understanding of the national infection rates for CIEDs, and that adoption and iteration of guidelines will continue to reduce complication rates.¹⁷

Conclusion

In summary, a comprehensive change in practice with the aim to reduce infection rates was successful, and also had the added and unforeseen benefit of reducing overall complication rates from device insertion.

Key messages

• Cardiac implantable electronic device (CIED) insertion results in significant complications in a small proportion of individuals, causing morbidity, cost to the NHS and occasionally mortality
• A comprehensive change in clinical practice significantly reduced CIED-related complications
• A reduction in infection rates was seen, which was the principal aim of the new guidance, but this did not reach statistical significance

Conflicts of interest

MD reports receiving speaker fees from Biotronik in the past 2 years. EF, GF: none declared.

Funding

None.

Study approval

All research adhered to the World Medical Association’s declaration of Helsinki. No national ethical approvals were required and local approvals were secured.

References

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