European Journal of Cardiovascular Medicine

Cardiac implantable electronic devices (CIEDs), such as pacemakers, are being implanted more frequently worldwide, playing a crucial role in preserving millions of lives. As life expectancy continues to rise, the demand for these devices is also increasing. Typically, CIEDs are placed in a subcutaneous pocket located in the pectoral area. However, these pockets can sometimes become eroded or infected, which can lead to significant health complications and even mortality. In the United States, hospitalizations due to CIED infections saw a notable increase between 1996 and 2003, with an overall rise of 3.1 times. Specifically, hospitalizations rose 2.8 times for permanent pacemakers and 6.0 times for implantable cardioverter defibrillators.(1)

In a population-based cohort study involving 46,299 consecutive patients from the Danish population, the incidence of pocket infection was 4.82 per 1,000 device years after the primary implantation and 12.12 per 1,000 device years after device replacement. (2) Few studies also point to the incidence of pocket infection in the range of 0.13% to 19.9%, depending upon the profile of patients and devices. (3) Another study by F Eberhardt et al found the rate of pocket complication to the tune of 4.5%.(4)

CIED pocket infections are more prevalent among individuals with comorbidities like diabetes, chronic kidney diseases, etc, and they also pose a significant risk to patient outcomes. These infections can result in a twofold increase in the risk of death during hospitalization.

If we see the pattern of CIED implantation profile in India, 80% of them are pacemakers for bradyarrhythmia, according to one survey conducted in 2016. (5)

Factors that have been identified by various studies playing a role in pocket complications, namely infection and erosion, are summarized in Table 1. (6)

CIED pocket infections are primarily caused by microorganisms, with Gram-positive bacteria being the most common, accounting for 70-90% of cases. The specific microorganisms isolated include Coagulase-negative Staphylococci (CoNS)(37.6%) and  Staphylococcus aureus (30.8%), with 33.8% of these cases potentially being Methicillin-resistant Staphylococcus aureus (MRSA) and the rest others. Gram-negative bacteria are seen in  8.9% of cases. Occasionally, fungi can also be involved in these infections.

Clinical Impact: CIED pocket infections significantly contribute to increased Medical costs and increased mortality. The severity of these infections can range from mild pocket site erythema to severe conditions such as Fungal Endocarditis and Septicaemia. However, the crisis can be tied on multiple occasions by meticulous management with the removal of the PG system. But this may not be in every case. In one article by Sean D. Pokorney, MD, cumulative one-year mortality can be as high as 30% without extraction at 30 days, and it will come down to 18.6% if done at 6 days. (7)

Treatment Approach:

The treatment of pocket infection or erosion following pacemaker implantation depends on the infection's severity. Mild cases may be managed with antibiotics, while more severe cases require complete explantation of the pulse generator system with antibiotic coverage. In cases with minimal inflammation and culture-negative infections, a conservative approach may be considered to retain the original pulse generator, but this has a higher failure rate. This method is often used in resource-limited settings due to financial constraints, involving wound debridement and device replacement after disinfection. However, it is less ideal than complete explantation and reimplantation, which remains the preferred approach.(8).

This article aimed to evaluate the risk factors of pocket complications and the outcome of the conservative strategy in some cases. All the CIED implantations done in our centre were Pacemakers for bradyarrhythmia in the study period.

We at Assam Medical College, Dibrugarh, Assam, India retrospectively analysed the patient records of individuals who underwent pacemaker implantation and later presented with pocket infections and erosions. Data on patients with pocket complications were gathered from their files and through telephonic inquiries. All patients underwent pacemaker implantation at our institute due to syncope, so transvenous pacing was present in all cases, indicating a common risk factor.

We analysed data on demographics, types of pacemakers, comorbidities, and risk factors for pocket complications and statistical analyses were performed using IBM SPSS 2020.

In your study, you analysed pocket complications by grouping subjects based on the types of complications listed in Table. We aimed to compare risk factors and comorbidities associated with these complications, specifically focusing on pocket erosion. Pocket infection is typically defined as per the wrap-it trial in various studies as shown in the following paragraph.(9)

1. Superficial Cellulitis: Involves infection of the skin and subcutaneous tissues around the CIED pocket. Associated with complications such as Wound dehiscence, Erosion and Purulent drainage
2. Deep Incisional or Organ/Space SSI (Surgical Site Infection): Refers to infections that involve deeper layers, including the CIED generator pocket. Must meet the CDC criteria for SSI, regardless of the time elapsed since surgery.
3. Persistent Bacteraemia
4. Endocarditis (10)

But for simplicity, we have classified the pocket infection according to the EHRA consensus document into two grades.

 Grade (a) definite pocket infection including pocket erosion, erythema, pus discharge, and sinus formation.

Grade (B) with pocket infection and systemic signs of inflammation and infective endocarditis(6)

Management at our centre is classified into three groups, as outlined in Table 8, and follows EHRA guidelines. We have also implemented additional device salvage options with a conservative approach for patients experiencing pocket erosion. This approach is applied when blood and pus cultures are negative, and local signs of inflammation are minimal. In these cases, we perform extensive wound debridement (as shown in Figures 1-3) and reimplant the same pulse generator after it has been treated with Betadine and absolute alcohol. This is done following antibacterial lavage of the pocket and a minimum of five days of intravenous antibiotics. This novel method has received support from multiple small case series and studies.(11,12).

Study Period: Two and a half years from January 1, 2022, to July 31, 2024.

Patient Recruitment: 1056 patients were implanted with pacemakers at our centre and n=33 patients came with pocket erosion.

Pacemaker Types: The study included both single-chamber (VVIR) and dual-chamber (DDDR) pacemakers. Box changes were analysed separately due to their distinct characteristics.

Complications: 33 patients experienced symptomatic pocket complications, such as cellulitis, hematoma, and pocket erosion, requiring surgical intervention (figure 1).

Patient Data:

Basic demographic information and relevant comorbidities for study participants are detailed in Table 2.

 Indications of pacemaker implantation in de novo cases are listed in Table 3. Complete heart block in resting ECG was the most common (64.2%) pacemaker indication in our study population undergoing de novo PG implantation, followed by bundle branch block, sick sinus syndrome, advanced 2nd-degree AV block, and AF with symptomatic bradycardia.

The mean age of patients with pocket erosion is 69.34(±7.2yr). Overall, the male-female ratio is 2.3:1 among all implantations, but in pocket erosion, this ratio is 2:1, depicting a slightly higher proportion of male patients who have pocket infections compared to females. If we discuss the pacemaker profile (table 4), the majority were single chamber devices accounting for 55%, followed by dual chamber PG for another  24.5%,  and the remaining 20.2% had box change.

 Among the 1,056 total pacemaker implantations, 33 cases presented with pocket erosion/infection, resulting in an overall incidence of 3.1%. In our study, we conducted a clinical and risk factor analysis of these patients to identify potential predictors of pocket complications.

The various risk factors associated with pocket erosion in our study are summarized in Table 5. Among the 33 cases of pocket erosion, diabetes mellitus was present in 16 patients (48.5%), making it one of the most common comorbidities linked to pocket erosion. Hypertension was observed in 18 cases (55%), suggesting a strong association with pocket complications. Chronic kidney disease (CKD) was present in 8 cases (24%), indicating that renal dysfunction may contribute to a higher risk of pocket erosion. Chronic obstructive pulmonary disease (COPD) was seen in 11 cases (33%), which may indicate the role of chronic inflammation and hypoxia in the risk of infections or erosion. Dyslipidaemia was reported in 8 patients (24%), which aligns with previous findings suggesting its possible role in vascular complications and poor wound healing. Antiplatelet therapy was used in 2 cases (6%), while anticoagulants were used in 1 case (3%), showing a relatively low contribution to pocket erosion in this cohort. Hypothyroidism was present in 2 cases (6%), though its impact on pocket erosion remains uncertain. Notably, no cases were found with immunosuppressive status (excluding diabetes), suggesting that other factors may have played a greater role in pocket erosion risk.

Among the 217 cases of pulse generator replacements (box changes), 11 patients (5%) developed pocket erosion.

On studying the degree of pocket infection in Table 6, we are mainly receiving grade A pocket infection. And we have zero cases of infective endocarditis or lead-associated vegetation.

The trend of pus culture growth is depicted in Table 6. Most of the patients have no growth of microorganisms and 4 cases have Staphylococcus aureus as growth. One patient has Klebsiella, and another has Acinetobacter baumanni.

Management Approach: We have classified management into three arms and their Outcomes are summarised in the accompanying Table 8.

In the 16 (48%) patients having de novo PG implications, we managed with PG system explanations, with wound debridement and closure of the wound. In one unfortunate patient, we have skin necrosis over the PG, which needed extensive local flap repair, and ultimately resulted in a good cosmetic outcome.

Post explantation of the PG system, new PG  reimplantation was done on the contralateral side after a Brief interval with temporary pacing back up through the femoral route, till the signs of sepsis resolve and the infected wound starts healing. In 11 (33%)  cases having pulse generator replacement, we removed the pulse generator and extensive debridement of devitalized tissue was done along with antibiotic lavage of the infected pocket. Redundant lead was cut short and capped, or conductors were covered by the nonconducting lead envelope and buried in the subcutaneous tissue, followed by the pocket closure. The second PG system was implanted on the contralateral side (figure 3,4).

A total of six patients (18%) who underwent de novo implantations have expressed reluctance towards the new PG system for various reasons. These patients exhibit minimal signs of local or systemic inflammation, with negative results for both pus and blood cultures. As previously outlined in the methodology, these individuals have been managed using a conservative approach. In one patient in a conservative approach,  we performed flap reconstruction of the pacemaker site when the laceration was large and tension-free closure was not possible; they later showed good cosmetic outcomes(figure 5).  

During follow-up, we have only one patient (Figure 6,7) who received conservative treatment, and showed no further erosion or signs of cellulitis during the 6-month follow-up.

Pocket infection is one of the major complications following cardiac implantable electronic device (CIED) implantation, causing significant distress to both patients and physicians. This challenge is particularly pronounced in developing nations, where the cost of pulse generator (PG) reimplantation may be prohibitively expensive for many patients. The clinical and epidemiological profiles of our patients differ somewhat from those observed in Western studies.

The pocket infection rate in our study was 3.1%, which is higher than the <2% rate reported by a joint working party of BSAC, BHRS, BCS, BHVS, and BSE. Additionally, Margey et al. documented a lower infection rate of 1.2% in their study. However, our findings align more closely with data from Daniel J. Cantillon, MD et al., who conducted a nationwide survey of pacemaker complications using US healthcare claims. Their study found a 30-day infection rate of 1.15% and a long-term infection rate of 2.42%, which is comparable to our observed infection rate.(13–15)

Further analysis of the available literature reveals a wide variability in the reported incidence of pocket complications, emphasizing the role of patient-specific risk factors and procedural characteristics. Eberhardt et al. reported a pocket complication rate of 4.5%, which is slightly higher than our observed 3.1%, while Jonas et al. documented a significantly higher 16% complication rate. These discrepancies highlight the heterogeneous nature of CIED-related infections, influenced by factors such as patient comorbidities, adherence to aseptic techniques, surgical expertise, and antibiotic prophylaxis protocols. (4,16)

This variability underscores the importance of individualized risk assessment and tailored management strategies to mitigate pocket infections. It also reinforces the need for stringent infection control measures, particularly in high-risk groups such as those with diabetes, chronic kidney disease, or immunosuppressive conditions.

The European Heart Rhythm Association (EHRA) consensus document suggests that younger individuals are at a higher risk of pocket infections. However, in our study, the average age of patients with pocket infections is 69 years. This finding underscores the need for further research into the factors contributing to infections in older patients, which may differ from those affecting younger individuals. Understanding these dynamics is essential for improving prevention and treatment strategies for pocket complications. (6) Male sex is a significant risk factor for pocket infection as shown by a population-based study where there is a male-female ratio of 1.8:1 in pocket infection in tune with our finding of 2.3:1. (2) If we see the box change, the same Danish study has shown a 2.08% incidence of infection in box change, but in our case, it is 5%, which is much higher in our population. (2)

One more study by Goel et al has shown pacemaker pocket complication rate of 3.6% similar to ours. However we have deduced a  higher prevalence of diabetes (48%) and chronic kidney disease (CKD, 25%) in patients with pocket erosion compared to Goel et al.’s study from another Indian state (27.8% and 1.6%, respectively), while hypertension was prevalent in 55% of our cases versus a higher but unspecified rate in theirs, and coronary artery disease (CAD) was lower (6% vs. 14.8%). These differences may reflect regional variations in lifestyle, genetics, and healthcare access, influencing the prevalence and management of these comorbidities—diabetes and CKD potentially increasing infection risk via immune dysfunction, hypertension affecting wound healing, and CAD modulated by local risk factors and care practices. Such disparities underscore the role of regional factors in CIED infection outcomes, warranting further investigation.(17).

Our microbiology showed almost no growth in all the pus cultures, and next it was followed by Staphylococcus aureus in 4 (12%) patients, contrary to another study by Hussein et al, which showed no growth only in 12% of cases.(18) As opposed to 82% of cases in our setting, this may be due to the intermittent over-the-counter use of antibiotics which is more common in our country.

Management of pocket infections in patients with de novo pacemaker (PG) implantation is often straightforward and effective with complete PG system explantation. This is primarily due to minimal lead entrapment in the fibrotic tissue of the subcutaneous space and blood vessels. In contrast, managing pocket infections in patients undergoing device replacement (box change) poses significant challenges. These systems, implanted years earlier, are typically tightly encapsulated by fibrotic tissue and endothelialized by body structures. In such cases, treatment usually involves removing the pulse generator while cutting and burying the lead in the subcutaneous tissue. However, this approach can occasionally lead to complications, such as the development of discharging sinuses. A complete Lead extraction in these cases is quite challenging and we need a hybrid OT. There are multiple case reports of lead extraction by laser and special styles and sheaths.

In some of the patients having new implants, we have done a conservative approach to salvage the PG system, but we have failed in almost all except for one success, however, there are lots of studies that are claiming more success with the conservative approach, mostly from China and the Middle East. (8,12,19). Continuous in situ targeted antibiotics (CITA) now show promising results in carefully selected patients with device pocket erosion. The study done by Topaz et al in some eighty patients showed that patients undergoing CITA have a cure rate of 85% of pocket infection and resultant PG salvage. (20)

Patients coming with pocket infection in our study often present with undetected or poorly controlled diabetes and have limited access to antibiotics and adequate post-operative wound care, owing to the underdeveloped healthcare infrastructure and low-income status. The incidence of pocket infection is high, which is much more pronounced in cases of box change in our population. Also, diabetes is a well-known risk factor in almost half of our patients. So, we need a much more robust follow-up, a higher duration of antibiotic therapy, and more efficient pre- and post-operative handling of our patients to reduce this menace. The conservative approach, although a cost-effective strategy in resource-limited scenarios seldom succeeds

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