Muhammad R. Sohail

Risk Factor Analysis of Permanent Pacemaker Infection

Background. Several host- and procedure-related factors have been reported to increase the risk of permanent pacemaker (PPM) infection on the basis of descriptive analyses of case series. The purpose of this study is to assess the risk factors for PPM infection using case-control study methods.Methods. All patients who had a PPM implanted at our institution from January 1991 to December 2003 were retrospectively reviewed. Each patient who experienced a PPM infection was matched with 2 control subjects by age, sex, year of implantation, and duration of follow-up. Univariate and multivariable analyses were performed to identify significant risk factors for PPM infection.Results. Twenty-nine case patients and 58 control subjects met inclusion criteria. The majority (83%) of case patients presented with a pocket infection; a minority (10%) had PPM-related endocarditis. Staphylococcus species (69%) were the most common pathogens. On univariate analysis, previous PPM infection, malignancy, long-term corticosteroid use, multiple device revisions, a permanent central venous catheter, the presence of >2 pacing leads, and a lack of antibiotic prophylaxis at the time of PPM placement were associated with an increased risk of PPM infection. A multivariable logistic regression model identified long-term corticosteroid use (odds ratio [OR], 13.90; 95% confidence interval [CI], 1.27-151.7; P=.03) and the presence of >2 pacing leads versus 2 leads (OR, 5.41; 95% CI, 1.44-20.29; P=.01) as independent risk factors for PPM infection. In contrast, use of antibiotic prophylaxis prior to PPM implantation had a protective effect (OR, 0.087; 95% CI, 0.016-0.48; P=.005).Conclusions. These findings should assist clinicians in identifying patients who are at increased risk of PPM infection, as well as in developing strategies to minimize the modifiable risks.

Infective Endocarditis Complicating Permanent Pacemaker and Implantable Cardioverter-Defibrillator Infection

OBJECTIVE To describe management of patients with permanent pacemaker (PPM)- and implantable cardioverter-defibrillator (ICD)-related endocarditis. PATIENTS AND METHODS We retrospectively reviewed all cases of infection involving PPMs and ICDs among patients presenting to Mayo Clinics site in Rochester, MN, between January 1, 1991, and December 31, 2003. Cardiac device-related infective endocarditis (CDIE) was defined as the presence of both vegetation on a device lead or valve and clinical or microbiological evidence of CDIE. Of 189 patients with PPM or ICD infection who were admitted during the study period, 44 met the case definition for CDIE (33 PPM, 11 ICD). RESULTS The mean +/- SD age of patients was 67 +/- 14 years. Staphylococci (36 [82%]) were the most commonly isolated pathogens. Nearly all patients (43 [98%]) were treated with a combined approach of complete hardware removal and parenteral antibiotics. The median duration of antibiotic treatment after infected device explantation was 28 days (interquartile range, 19-42 days). Device leads were removed percutaneously in 34 cases (77%); only 7 cases (16%) required surgical lead extraction. Percutaneous extraction was uncomplicated in 15 patients with lead vegetation greater than 10 mm in diameter. Six patients (14%) died during hospitalization. Twenty-seven (96%) of 28 patients remained infection free at their last visit (median follow-up, 183 days; intraquartile range, 36-628 days). CONCLUSION Prompt hardware removal and prolonged parenteral antibiotic administration decrease mortality among patients with CDIE. The presence of a large (> 10 mm in diameter) vegetation on a lead is not a contraindication for percutaneous lead extraction.

Frequency of Permanent Pacemaker or Implantable Cardioverter-Defibrillator Infection in Patients with Gram-Negative Bacteremia

BACKGROUND Despite the frequent occurrence of bacteremia due to gram-negative organisms in patients with underlying permanent pacemakers (PPMs) or implantable cardioverter defibrillators (ICDs), the outcome and treatment of these patients has received scant attention. In patients with PPMs or ICDs who have Staphylococcus aureus bacteremia, 45% have PPM/ICD infection. METHODS We conducted a retrospective cohort study over a 7-year period to assess the clinical features and frequency of PPM/ICD infection in patients with gram-negative bacteremia, as well as the incidence of relapse in patients for whom the device was not removed. RESULTS Forty-nine patients were included in the study; 3 (6%) had either definite (2 patients) or possible (1 patient) PPM/ICD infection. Both patients with definite PPM/ICD infection had clear infection of the generator pocket. None of the other patients with alternate sources of bacteremia developed PPM/ICD infection. Thirty-four patients with retained PPM/ICD were observed for >12 weeks (median time, 759 days), and 2 (6%) developed relapsing bacteremia, although they each had alternative sources of relapse. CONCLUSIONS In sharp contrast to S. aureus infection, PPM/ICD infection in patients with gram-negative bacteremia was rare, and no patients appeared to have secondary PPM/ICD infection due to hematogenous seeding of the system. Despite infrequent system removal in these patients, relapsing bacteremia among patients who survived initial bacteremia was rarely seen. If secondary PPM/ICD infection occurs in patients with gram-negative bacteremia, it is either uncommon or it is cured with antimicrobial therapy despite device retention.

Incidence of Infective Endocarditis Caused by Viridans Group Streptococci Before and After Publication of the 2007 American Heart Association's Endocarditis Prevention Guidelines

Background— The American Heart Association published updated guidelines for infective endocarditis (IE) prevention in 2007 that markedly restricted the use of antibiotic prophylaxis in certain at-risk patients undergoing dental and other invasive procedures. The incidence of IE caused by viridans group streptococci (VGS) in the United States after publication of the 2007 American Heart Association guidelines has not been reported. Methods and Results— We performed a population-based review of all definite or possible cases of VGS-IE using the Rochester Epidemiology Project of Olmsted County, Minnesota. Patient demographics and microbiological data were collected for all VGS-IE cases diagnosed from January 1, 1999, through December 31, 2010. We also examined the Nationwide Inpatient Sample hospital discharge database to determine the number of VGS-IE cases included between 1999 and 2009. We identified 22 cases with VGS-IE in Olmsted County over the 12-year study period. Rates of incidence (per 100 000 person-years) during time intervals of 1999–2002, 2003–2006, and 2007–2010 were 3.19 (95% confidence interval, 1.20–5.17), 2.48 (95% confidence interval, 0.85–4.10), and 0.77 (95% confidence interval, 0.00–1.64), respectively (P=0.061 from Poisson regression). The number of hospital discharges with a VGS-IE diagnosis in the Nationwide Inpatient Sample database during 1999–2002, 2003–2006, and 2007–2009 ranged between 15 318 to 15 938, 16 214 to 17 433, and 14 728 to 15 479, respectively. Conclusions— On the basis of data complete through 2010, there has been no perceivable increase in the incidence of VGS-IE in Olmsted County, Minnesota, since the publication of the 2007 American Heart Association endocarditis prevention guidelines.

Infectious Complications of Percutaneous Vascular Closure Devices

OBJECTIVE To describe the infectious complications of percutaneous vascular closure devices (PVCDs) on the basis of our institutional experience with PVCDs and the published medical literature. PATIENTS AND METHODS We retrospectively reviewed all cases of PVCD-related Infection seen at the Mayo Clinic in Rochester, Minn, between January 1, 2000, and December 31, 2003, and searched the English language medical literature for all previously published reports. RESULTS We identified 46 cases in the medical literature and 6 cases from our Institutional database. The median age of patients was 63 years (range, 40-79 years). Diabetes mellitus and obesity were the most common comorbidities. The median Incubation period from device Insertion to presentation with access-site infection was 8 days (range, 2-29 days). The most common presenting symptoms were pain, erythema, fever, swelling, and purulent drainage at the access site. Mycotic pseudoaneurysm (22 cases) was the most common complication. Staphylococcus aureus was responsible for most (75%) of the Infections. All patients underwent surgical debridement, and 54% required reconstructive procedures. The median duration of antibiotic treatment was 28 days (range, 7-42 days). The mortality rate was 6% (3 patients). CONCLUSIONS Infection associated with PVCD placement is uncommon but is an extremely serious complication. Morbidity is high, and aggressive medical and surgical interventions are required to achieve cure.

Implantation success and infection in cardiovascular implantable electronic device procedures utilizing an antibacterial envelope.

Background:  Cardiovascular implantable electronic device (CIED) infection rates are increasing faster than implantation rates. More effective antimicrobial prophylaxis may help reduce CIED infections and improve clinical outcomes. The AIGISRx® antibacterial envelope is a polymer mesh implanted in the generator pocket with the CIED. After implantation it releases two antibiotics, minocycline and rifampin, that have been shown to reduce infections associated with other medical devices. The purpose of this retrospective cohort study is to determine the rate of CIED implantation success and CIED infection in procedures utilizing the antibacterial envelope.

Impact of timing of device removal on mortality in patients with cardiovascular implantable electronic device infections

BACKGROUND Cardiovascular implantable electronic device (CIED) infections are associated with increased mortality. However, detailed analyses of the impact of device removal on mortality have been limited. OBJECTIVE This study sought to evaluate the impact of timing device removal on mortality in patients with CIED infections. METHODS We retrospectively reviewed all cases of CIED infections seen at Mayo Clinic Rochester between 1991 and 2008. The impact of device removal on 30-day and 1-year mortality was evaluated using Cox proportional hazards models. RESULTS Of 416 patients with CIED infection, 23 (5.5%) died by 30 days and 61 (14.6%) died by 1 year. Forty-four (12.0%) developed complications related to device removal, and 3 (0.8%) died. Complete procedural success was achieved in 341 (81.9%) and clinical success in 391 (93.9%) cases. In multivariate analysis, antimicrobial therapy without device removal was associated with a 7-fold increase in 30-day mortality (hazard ratio [HR] 6.97, 95% confidence interval [CI] 1.36 to 35.60). Although device removal complications were associated with increased mortality at 30 days (HR 4.33, 95% CI 1.47 to 12.70) and at 1 year (HR 3.77, 95% CI 1.88 to 7.55), immediate device removal, when compared to delay in device removal in favor of initial conservative therapy with antimicrobials alone, and no device removal, was associated with a 3-fold decrease in 1-year mortality (HR 0.35, 95% CI 0.16 to 0.75). CONCLUSION Although device removal resulted in fatal complications in a few patients, the mortality associated with a delay in device removal was significantly higher. Therefore, early and complete device removal was associated with improved outcomes.

Timing of the most recent device procedure influences the clinical outcome of lead-associated endocarditis results of the MEDIC (Multicenter Electrophysiologic Device Infection Cohort).

OBJECTIVES The purpose of this study was to determine whether the timing of the most recent cardiac implantable electronic device (CIED) procedure, either a permanent pacemaker or implantable cardioverter-defibrillator, influences the clinical presentation and outcome of lead-associated endocarditis (LAE). BACKGROUND The CIED infection rate has increased at a time of increased device use. LAE is associated with significant morbidity and mortality. METHODS The clinical presentation and course of LAE were evaluated by the MEDIC (Multicenter Electrophysiologic Device Cohort) registry, an international registry enrolling patients with CIED infection. Consecutive LAE patients enrolled in the Multicenter Electrophysiologic Device Cohort registry between January 2009 and May 2011 were analyzed. The clinical features and outcomes of 2 groups were compared based on the time from the most recent CIED procedure (early, <6 months; late, >6 months). RESULTS The Multicenter Electrophysiologic Device Cohort registry entered 145 patients with LAE (early = 43, late = 102). Early LAE patients presented with signs and symptoms of local pocket infection, whereas a remote source of bacteremia was present in 38% of patients with late LAE but only 8% of early LAE (p < 0.01). Staphylococcal species were the most frequent pathogens in both early and late LAE. Treatment consisted of removal of all hardware and intravenous administration of antibiotics. In-hospital mortality was low (early = 7%, late = 6%). CONCLUSIONS The clinical presentation of LAE is influenced by the time from the most recent CIED procedure. Although clinical manifestations of pocket infection are present in the majority of patients with early LAE, late LAE should be considered in any CIED patient who presents with fever, bloodstream infection, or signs of sepsis, even if the device pocket appears uninfected. Prompt recognition and management may improve outcomes.

Clinical predictors of cardiovascular implantable electronic device-related infective endocarditis

Background: Cardiovascular implantable electronic device (CIED)‐related infective endocarditis (CIED‐IE) is a serious complication of cardiac device infection and is associated with increased mortality. At present, there exist no criteria to predict CIED‐IE in patients who present with CIED infection.

Infective endocarditis due to Propionibacterium species

Propionibacterium species rarely cause infective endocarditis. When identified in blood cultures, they may be inappropriately disregarded as skin flora contaminants. The purpose of this study was to characterize the clinical presentation and management of endocarditis due to Propionibacterium species. All cases of endocarditis due to Propionibacterium species that were treated at the Mayo Clinic, Rochester, USA were retrospectively reviewed, and the English language medical literature was searched for all previously published reports. Seventy cases, which included eight from the Mayo Clinic, were identified (clinical details were available for only 58 cases). The median age of patients was 52 years, and 90% were males. In 79% of the cases, the infection involved prosthetic material (39 prosthetic valves, one left ventricular Teflon patch, one mitral valve ring, one pulmonary artery prosthetic graft, three pacemakers, and one defibrillator). Blood cultures were positive in 62% of cases. All 22 cases with negative blood cultures were microbiologically confirmed by either positive valve tissue cultures (n = 21) or molecular methods (n = 1). Endocarditis was complicated by abscess formation in 36% of cases. The majority (81%) of patients underwent surgery, either for valve replacement and debridement of a cardiac abscess, or removal of an infected device. Crude in-hospital mortality was 16%. The median duration of postoperative antibiotic treatment was 42 days. Patients were commonly treated with a penicillin derivative alone or in combination with gentamicin. On the basis of the above data, it is recommended that infective endocarditis should be strongly suspected when Propionibacterium species are isolated from multiple blood cultures, particularly in the presence of a cardiovascular device.