OBJECTIVE: To summarize the clinical manifestations and surgical management experience of refractory pacemaker-associated infections in order to improve the cure rate of such infections. METHODS: To analyze the hospitalization and follow-up data of refractory pacemaker-associated infections admitted to Peking University People’s Hospital, to summarize the experience and explore the pattern. RESULTS: A total of 18 cases of refractory pacemaker-associated infections were admitted in 13 years, including 14 cases of local infection and 4 cases of infective endocarditis, and all 18 patients were cured and discharged after comprehensive treatment and surgical management. Conclusion: Refractory pacemaker-associated infection is a rare complication. Based on rational use of antibiotics and comprehensive treatment, proper surgical intervention is important, including local debridement, complete removal of the pacing system, and even happy surgery. The key is prevention to reduce such complications. Liu Gang, Department of Cardiac Surgery, Peking University People’s Hospital, Beijing, China
Keywords: pacemaker; infection; surgical treatment
Surgical Treatment of Refractory Infection Related Permanent Pacemaker
Liu Gang, Xie Jiyan, Li Xuebin, Guo Jihong.Cardiac Surgery Department of People’s Hospital, PeKing University, Beijing(100044)
[Abstract] Objective To describe the clinical manifestation and therapy experiences of permanent pacemaker related refractory infection. methods We reviewed all the refractory cases of We reviewed all the refractory cases of infection involving permanent pacemaker among patients presenting to Peking University People’s Results there are 18 cases of permanent pacemaker related refractory infection. 14 local infections and 4 endocarditis. All patients were cured by a combined approach of complete hardware removal and parenteral antibiotics. Surgical intervene is mandatory, debridement thoroughly, remove all the pacemaker system and combined use of antibiotics can cure almost all patients. Even so, some need open-heart surgery. The key points is prevention of this complication.
[Key words] permanent pacemaker; infection; surgical treatment
The incidence of infection after permanent pacemaker implantation ranges from 0.5% to 5%, with a mean of 2% [1,2]. We analyzed the cases of refractory pacemaker-associated infections over the past decade and summarized the causes, clinical manifestations and treatment methods in order to draw attention to refractory pacemaker-associated infections and improve the cure rate.
Clinical data
A total of 18 cases of pacemaker-associated refractory infections were hospitalized in our hospital from January 1, 1995 to April 31, 2008, 11 men and 7 women, aged 59±12 years (21-74 years), including 14 cases of pacemaker capsular bag or electrode stump infections and 4 cases of pacemaker-associated endocarditis.
Definition: Pacemaker-associated infections include local infections and infective endocarditis: local infections are divided into pacemaker pouch infections and electrode stump infections: pacemaker pouch is a local wound that does not heal or breaks down after healing; electrode stump infections refer to residual electrodes after debridement with local inflammatory manifestations and/or oozing pus. Pacemaker-associated infective endocarditis can be diagnosed if the patient with the pacemaker has manifestations of infection, if cardiac ultrasound reveals redundancy on the electrodes or valves; or if Duke’s infective endocardial index is met [3]. Refractory infections were defined as recurrence after (i) debridement, which did not heal over time, (ii) infection in the heart chambers, and (iii) combination of other complications.
STATISTICAL METHODS: Means ± standard deviations (±s) were selected according to whether the data distribution conformed to a normal distribution, and data that did not conform to a normal distribution were expressed as median and 25th and 75th percentiles (IQR).
Follow-up methods: All cases were followed up by outpatient follow-up or telephone, and the follow-up included patients’ complaints, the presence of systemic infection or local inflammatory manifestations such as fever, and records of relevant treatment and examination.
Results
All of the 18 patients were implanted outside the hospital except for one patient who had a pacemaker implanted in our hospital. 7 patients had a pacemaker for the first time, and 11 patients had a pacemaker for two or more times. The median time window between the onset of infection and the last pacemaker installation was 5 months (IQR 1-24 months).
14 Three of the localized infection cases were cleared for the first time, and the remaining cases were treated with multiple clearances, with a history of up to three clearances (Table 1). In contrast, in all cases, the pacing electrodes were not removed during previous debridement, and the median time between the first infection and this admission was 8 months, with a maximum of 240 months.
Pathogenesis
Bacteriological cultures were not performed in 4 of the 18 cases, and wound secretion cultures were performed in 10 patients with localized infections; 4 were negative and 6 were positive, including 3 Staphylococcus epidermidis, 1 Staphylococcus griseus, 1 Burkholderia onionis, and 1 Corynebacterium spp. Blood cultures were performed in 4 cases of infective endocarditis, 2 for Staphylococcus aureus, 1 for Staphylococcus haemolyticus, and 1 negative (Table 1).
Treatment
Among the 14 cases of local infection, one case was purely debridement, 12 cases were debridement plus removal of the pacing system, and one case had infective endocarditis due to failure to remove the pacing device while it was placed in the contralateral subclavian vein, and the contralateral local tissue infection occurred in this case 1 month later. All cases were discharged with 11.6±5.1 days (4-24 days) of postoperative intravenous antibiotics.
One of the four cases of infective endocarditis was associated with coronary artery disease and the pacing electrodes were removed at the same time as coronary artery bypass grafting. In all four cases, the pacing leads and pacemakers were happily removed under extracorporeal circulation, and the epicardial pacing leads were left in place after surgery, with temporary epicardial pacing and normal body temperature.
There was no death in this group, and one case was lost after surgery, with a follow-up rate of 94.4%. The median follow-up time was 11 months (25th and 75th percentiles were 7 months and 49 months). Four cases of infective endocarditis did not show recurrence or local infection during follow-up. One case of local infection failed to remove the pacing lead and developed into infective endocarditis and underwent open surgery, while the rest of the debridements did not recur.
Discussion
Pacemaker-associated infections are rare, with a statistical incidence of 0.5-2% and a 2% chance of sepsis or infective endocarditis in infected patients, but infective endocarditis in pacemakers is a serious complication with a mortality rate of 10-30% when it occurs [1, 2, 4].
I. Route of infection
Pacemaker-associated infection comes from two main sources, one of which is local wound bacterial retention during pacemaker installation, which is related to the duration of the surgical operation and the aseptic technique of the operator. Once the capsule site is infected, bacteria at the pacemaker capsule can spread along the electrodes to the endocardium and electrode tip. Another possible source of infection is the implantation of transient bacteremia along the pacing lead, either associated with the capsular bag or unrelated to it. The most common pacemaker-associated infections are capsular bag infections, where the infecting pathogens are mostly Staphylococcus and Corynebacterium spp. Hematogenous implantation of distant foci of infection is mostly seen in advanced infections, associated with infections with Staphylococcus aureus, Streptococcus, Gram-negative bacteria and fungi [5]. The experience of the operator, the time of surgery and reoperation are potential risk factors [6]. In our group, 12 cases (67%) were re-installed pacemakers, and all four cases of infective endocarditis were after re-installation of the pacemaker, suggesting that the occurrence of infection is associated with multiple operations.
Our data show that the time from the last pacemaker installation to the appearance of infection ranged from 1-96 months, with a time window of less than 12 months in 14 patients and a longest time window of 96 months in one case. This patient had a clear causative factor for the onset of infection, which was a secondary infection after local trauma involving the pacing system. In the other 3 cases, the infections did not exceed 24 months.
II. Diagnosis
The diagnosis of localized infection is not difficult. Pacemaker-associated infection can be diagnosed in patients with a wound that fails to heal after pacemaker implantation with or without localized wound exudation with or without inflammatory manifestations such as redness, swelling, heat, and pain, or in patients with these symptoms after wound healing. We emphasize that in these patients with systemic infections, the possibility of endocarditis should be considered and early blood cultures and transesophageal echocardiography should be performed. Echocardiography is important for the diagnosis of pacemaker-associated infective endocardium, and the diagnosis of pacemaker-associated infective endocarditis is mainly based on Duke’s criteria; therefore, pacemaker-associated infective endocarditis can be diagnosed in cases with pacemakers as long as the blood culture is positive and there are superfluous organisms on the electrodes [7].
III. Treatment
(i) Complete removal of the pacing system
Complete removal of the pacing system is the most effective and fundamental method for the treatment of pacemaker-associated infections, which is in accordance with the principle of “removal of foreign bodies and unobstructed drainage” in the treatment of surgical infections. Therefore, once the diagnosis of pacemaker-associated infection is clear, the pacemaker and electrodes should be completely removed as soon as possible. The vast majority of our cases had been treated externally with debridement, and 9 cases (50%) had undergone multiple debridements outside of the hospital, and one case had a persistent infection that had been debridged for 240 months. The formation of local scar and sinus tracts made re-clearing difficult. The reason for the recurrence of infection in these cases, we believe that the incomplete debridement and the failure to completely remove the pacing system, which resulted in a loss of work, were the root causes. In our group, one case failed to remove the electrode through local wound and transferred this electrode to the contralateral chest wall for burial, the cost of which was the occurrence of infected endocardium in this case and the necessity to perform a happy surgery. Therefore, thorough and correct debridement and removal of the pacemaker and infected electrodes is the key to treating refractory pacemaker-associated infections, and happy surgery should be considered for electrodes that really cannot be removed through local wounds.
In our group, four cases of pacemaker-associated endocarditis underwent open heart surgery. Two of them showed local infection and the pacing leads were difficult to be removed despite repeated debridement, while the other two patients had large intracardiac superfluous organisms that were difficult to be controlled by antimicrobial agents and one had coronary artery bypass grafting at the same time.
In the treatment of pacemaker-associated infective endocarditis, it is not necessary to perform open surgery if the pacing lead can be removed locally [8], and we know that in most cases the pacing lead can be removed through local wounding. However, for superfluous organisms larger than 10 mm in diameter, surgery should be performed [9]. However, not all patients can be paced percutaneously, and in Sohail et al.’s data, 11% had complications during percutaneous pacing lead removal, including heart valve damage, venous tears, bleeding complications, and electrode tip fracture requiring surgical removal. Therefore, percutaneous removal of pacing leads requires experienced operators and should be performed with open surgery when the operation is difficult or fails.
(B) Application of antimicrobial agents after debridement
In this group of cases with local infection, appropriate antibiotics were selected after debridement, and the course of treatment was 4-24 days, with an average of 11.6±5.1 days. All cases were cured after surgery except for one case in which the pacing lead was not successfully removed due to endocarditis and was converted to surgery. For the treatment of infective endocarditis, most of the literature advocates the postoperative application of antimicrobial agents for 4-6 weeks [10], our experience is to continue the application of antibiotics for 4 weeks after the normalization of the patient’s temperature after surgery, the postoperative course of antibiotics in our group of 4 cases of infective endocarditis was 35-38 days with an average of 36.5±1.3 days, and all 4 cases were cured without recurrence or death. Our data prove that pacemaker-related local or systemic infections can be completely cured by the rational application of antibacterial drugs based on the complete removal of the pacing system. The application of antimicrobial drugs for about 10 days after debridement is sufficient for local infection cases, while for infected endocardial cases, the principle of full dosage and full course of treatment should be followed.
(iii) Pacemaker reimplantation
After complete removal of the endocardial device and control of the infection, the need for re-installation of the pacing device should be carefully evaluated. Some scholars believe that reimplantation of the pacemaker is not necessary in 1/3 of cases, but in this group of cases, all of them were pacemaker-dependent patients after preoperative evaluation. Among the 14 cases of local infection in this group, one case was judged to be free of serious infection intraoperatively and the pacemaker was reimplanted in situ after disinfection, but this method is not advocated. The time to pacemaker reinsertion in these 8 cases was 4.6±3.4 days (0-10 days) after debridement, and the time to pacemaker reinsertion in the 4 patients with infected endocardium was 22-32 days. Some authors recommend that patients with pacemaker-associated endocarditis should delay implantation until after 6 weeks. In our experience, reimplantation is possible as long as there is no bacteraemia. Before pacemaker reimplantation, epicardial or endocardial temporary pacemakers are fitted in pacemaker-dependent patients. All four patients with endocarditis in our group were paced by epicardial temporary pacemakers for a maximum of 32 days after surgery, during which time the temporary pacemaker pacing parameters and pacing should be closely observed to prevent adverse consequences of temporary pacing disorders.
Prevention of pacemaker-associated infections
Prevention of pacemaker-associated infections is the key. The following aspects should be grasped: (1) strict aseptic operation and delicate surgery to reduce bleeding and tissue damage; (2) proper prophylactic application of antibiotics in the perioperative period [11]; (3) active prevention of infection in patients with second pacemaker replacement, and strict disinfection before implantation if the original pacemaker is still used; (4) strict control of pacemaker implantation indications to reduce unnecessary implants.
References