Discussion
Our study demonstrates the feasibility, efficacy, and safety of CHG scrubbing of the generator pocket while avoiding complete capsulectomy in the management of CIED infections. The main findings of our study are:
Current rates of CIED infection have risen over the last several decades despite improved procedural techniques and prophylactic antibiotics, probably owing to a higher proportion of critically-ill patients being treated with implantable devices (particularly implantable cardiac defibrillators and resynchronization therapy devices). Several mechanisms have been proposed to explain device-related infections, including contamination during implantation, lead seeding during bacteremia episodes associated with distant infections, and skin erosion (which can be the cause or the consequence of a subclinical pocket infection). The risk of infection appears to be higher in patients undergoing generator replacement, lead or pocket revisions, device upgrades, and resynchronization device implantation. Given that 9% of patients presenting with a pocket infection have had a device-related infection in the past(18) and that a prior infection increases the risk of a future infection by 65%,(19) strategies to reduce the risk of infection recurrence are of paramount importance. Complete hardware removal undoubtedly plays a significant role in reducing this risk of reinfection and is recommended in current guidelines to achieve infection control.
Nevertheless, the appropriate management strategy for the generator pocket and the wound has yet to be established based on solid evidence.(5) This knowledge gap has led to many protocols, including the use of costly therapies with unproven clinical benefits.(20,21)
Total capsulectomy has been proposed to achieve resolution of the infection and is currently used by approximately 58-76% of centers, with no distinction made in current guidelines regarding the type of infection (i.e., pocket infection vs. bacteremia/endocarditis).(7,8) Furthermore, there is insufficient evidence to support its routine use, and capsulectomy is an arduous procedure associated with a significant risk of hematoma formation and the occasional need for pocket revision to control the bleeding.(6) The presence of post-procedural hematoma is associated with a substantial increase in the risk of infection (22) and could result in prolonged hospitalization and increased healthcare costs. Moreover, large hematomas frequently require OAC interruption, which is associated with significant stroke risks in patients with atrial fibrillation, the most frequent indication for OAC use. The hematoma formation rate in the present study is higher than that described in the MAKE IT CLEAN trial, which found hematoma formation in 6.1% of patients undergoing capsulectomy.(6) Interestingly, 6 out of the 7 hematomas were found in patients with a pocket infection, with only 1 in patients with infective endocarditis/bacteremia. As such, operators may perform more aggressive tissue debridement when managing pocket infections, thus explaining the higher rate of hematoma compared to the MAKE IT CLEAN trial.
Given the low cost, widespread availability, and low risk of adverse reactions associated with CHG, our current protocol is valuable by reporting the reduced risk of hematoma formation without increasing the risk of reinfection. To avoid adverse reactions associated with chlorhexidine, thorough washing of the pocket cavity is important, being careful not to exert excessive pressure during saline irrigation since high pressure can be associated with soft tissue damage. Moreover, allergic reactions to chlorhexidine are infrequent, with only 124 cases reported in the literature in over 40 years of use.(23)
As expected, the most frequently identified infectious organisms in our study were gram-positive bacteria (including MSSA, MRSA, and CoNS). Their presence explains this as normal skin flora in some patients and their ability to adhere to non-biological surfaces, creating biofilms. Biofilm mitigates antimicrobial effect, thus explaining the poor response to antibiotics to treat CIED infections if complete hardware removal is not performed. Notably, chlorhexidine can eradicate bacteria present in biofilm (and, possibly, on capsules),(9) which could explain our positive results.
Other protocols have been described to reduce the risk of recurrent infection in patients with CIED infection. Buckarma et al. described a protocol including surgical debridement, total capsulectomy, negative pressure, and surgical reevaluation 48 hours after the initial treatment.(24) Even though this protocol was associated with a reduction in the length of hospital stay, it failed to decrease the reinfection rates. Therefore, it is possible that many of the interventions applied in this protocol (including capsulectomy and negative pressure) are unnecessary and only increase procedural times and costs. Our reinfection rate is lower than previously published by Sohail et al., who described a 5% risk of recurrent/persistent infection.(25) These positive results are compelling, considering the high percentage of patients with pocket infection (50%) in our series, given that a more “aggressive” approach (i.e., complete capsulectomy) would be preferred by most physicians in cases of pocket infection/device extrusion. Thereupon, contrary to what would be expected, the use of a “less aggressive” (i.e., CHG irrigation) approach in patients with pocket or device-related infections had similar outcomes to a “more aggressive” approach. Likewise, although 54.9% of patients received a new device, with patients in the CHG having a numerically shorter time to reimplant than patients in the capsulectomy group (albeit statistically non-significant), there were no significant differences in the rate of reinfection. Finally, CHG scrubbing was associated with a substantial reduction in procedural times, an important finding considering the rising importance of increasing lab efficiency. Although variations in individual procedural times may exist between different hospitals (as it is highly related to operator experience), a more straightforward procedure (i.e., CHG irrigation) is expected to be associated with reduced procedural times, particularly since during capsulectomy operators must constantly address and undertake different actions to control bleeding (e.g. identifying the site of bleeding and the use of cautery, manual pressure, or artery ligation).