Cardiovascular Implantable Electronic Device Associated Infections Waseem Ahmad MD

Question ? Are cardiovascular implantable electronic devices Infections risen out of proportion as compare to overall increase in their use ? Yes No

Introduction Cardiovascular implantable electronic devices (CIED) include permanent pacemakers (PPMs), implantable cardioverter-defibrillators (ICDs), and left ventricular assist devices (LVADs). There is a high incidence of cardiovascular disease among the United States’ population and subsequently, an increasing number of patients undergoing placement of CIEDs to improve quality of life and survival.

Introduction When ICDs were first used in the 1980s, these devices were generally implanted by cardiac surgeons with the assistance of cardiologists. At that time, procedures were quite complex because the large generators required implantation within the abdomen and tunneled leads were placed epicardially via thoracotomy. Infection rates using this approach were reported as high as 17%. Over time, the generator size has decreased substantially, facilitating implantation in the pectoral region and insertion of trans venous leads through the subclavian vein in a single procedure significantly decrease the infection rate

Introduction Infectious complications of cardio vascular implantable electronic devices (CIED) have risen out of proportion to overall increases in use. The management of CIED infections is clinically challenging and it results in substantial morbidity and mortality for patients.

Introduction NHDS estimated that 4.1% to 5.8% of CIED devices became infected between 2004 and 2006. A study that reviewed NHDS data reported a 57% increase in infections but only a 12% increase in devices implanted between 2004 and 2006 . Although the exact reasons for this increase remain unknown, more device use among older patients and others with comorbid conditions may provide a partial explanation

Number of device-related infections related to the number of new implanted devices over time in the United States. (purple line) Number of infected implanted cardiac devices by year of hospitalization normalized to the year 1996. (blue line) Proportional increase in the number of devices implanted normalized to the year 1996.

Host risk factors for Infections 1.Heart failure 2.Diabetes 3.Renal insufficiency 4.Anticoagulation 5.chronic obstructive pulmonary disease 6.corticosteroid use, 7.dvanced age (>60 year) (Rising rates of cardiac rhythm management device infections in the United States: 1996 through 2003. J Am Coll Cardiol. 2006) (implantable cardioverter defibrillator infections: seven years of diagnostic and therapeutic experience of a single center. Clin Cardiol. 2010)

Procedural and device-specific factors 1.Not using appropriate Antimicrobial prophylaxis before PPM and ICD placement 2.The presence of two pacing leads 3.Generator replacement 4. Temporary pacing before implantation

Procedural and device-specific factors 5.Fevers within 24 hours before implantation. 6.Early reintervention for pocket hematoma or lead dislodgement. 7.Development of postoperative complications at the generator pocket.   (Risk factors associated with early- versus late-onset implantable cardioverter-defibrillator infections. J Interv Card Electrophysiol. 2011)

The type and complexity of the actual device as a risk factor Patients with dual chamber systems developed more infections ICDs might carry an increased risk compared with PPM. (Permanent pacemaker and implantable cardioverter defibrillator infection Arch InternMed 2007)

Question ? Which one is the most common organism related to CIED infections. Coagulase negative Staph Staphylococcus aureus Gram negative Rods Mycobacterium species Fugal pathogen

Microbiology Gram-positive organisms remain the predominant pathogens associated with CIEDinfection—specifically coagulase-negative staphylococci (CNS) or Staphylococcus aureus A recent Mayo Clinic study examining CIED infections reported CNS in 41% of patients, S aureus in 41% of patients, and various gram-negative bacilli,fungi, and Propionibacterium acnes in the remainder (Infective endocarditis complicatingpermanent pacemaker and implantable cardioverter-defibrillator infection.Mayo Clin Proc 2008)

Microbiology

DIAGNOSIS Patients with cardiac device infections can be divided into two broad clinical categories. The first group has infection limited to the generator pocket site, with or without associated bacteremia. The second group has a primary endovascular infection with lead vegetations or an infection of intra cardiac structures (endocarditis)

Symptoms and Signs CIED infections can present with a wide variety of symptoms and can often pose a diagnostic challenge for clinicians. 1. localized signs of inflammation at the generator pocket, such as erythema, warmth, fluctuance, wound dehiscence, tenderness, purulent drainage, or erosion of the generator or lead 2.CIED-associated endocarditis by the presence of lead or valvular vegetations on echocardiography or by whether the modified Duke criteria for infective endocarditis are met.

DIAGNOSIS Patients with suspected CIED infection, clinicians should perform 1. two sets of blood cultures, 2. tissue cultures from the generator pocket site, 3. lead tip cultures (when CIED will remove) Generator pocket cultures identified a causative pathogen in61%to81% lead tip cultures were positive in 63.3% to 79%of cases. Establishing the diagnosis of endocarditis by a positive lead culture without evidence of vegetation on transesophageal echocardiography or bacteremia can be misleading and inappropriately result in an extended duration of antimicrobial therapy.

DIAGNOSIS Transesophageal echocardiography (TEE) should be performed when patients are bacteremic, when endocarditis is suspected because of clinical findings, or when blood cultures are negative in the setting of recent antibiotic exposure. Caution should be exercised in cases of incidental masses associated with leads found in the absence of clinical suspicion for infection because many may be thrombotic in nature. Clinicians should not rely on transthoracic echocardiography for ruling out endocarditisbecause of low sensitivity in comparison to TEE

MANAGEMENT OF CARDIAC DEVICE INFECTIONS Mortality ranges from 7.4% to 18%with complete device extraction and from 8.4% to 41% with partial device extraction or antimicrobial therapy alone. Contemporary management of and outcomes from cardiac device related infections. Europace 2010)

Complete device extraction 1.generator or lead erosion (even without evidence of local inflammation), 2.Pocket infection 3. valve endocarditis 4. lead endocarditis Antimicrobials alone or in combination with partial device removal is associated with unacceptably high relapse rates and significant mortality 5. A superficial, localized infection of the incision without involvement of the device pocket is one exception .

Explantation VS percutaneous removal Historically, surgical lead removal with a thoracotomy was considered in patients with vegetation diameters less than 10 mm or with retained hardware after failed attempts with percutaneous lead removal. A recent update on the management on CIED infections and a poll of an expert panel advocated that percutaneous removal could be performed safely at high volume centers when lead vegetations are smaller than 2 cm. vegetations larger than 2 cm there are limited data on the appropriateness of percutaneous versus surgical removal. The decision regarding approach should be individualized (Update on cardiovascular implantable electronic device infections and their management: a scientific statement from the American Heart Association. Circulation 2010)

Complications from percutaneous lead extraction Damage to the tricuspid valve Subclavian vein laceration Hemothorax Pocket hematoma Fracture of lead tip

Antimicrobial Treatment Approach to antimicrobial treatment of adults with CIED infection J Am Coll Cardiol 2007

IDSA VS AHA Based on recent IDSA guidelines addressing the management of methicillin resistant S aureus (MRSA) infection, patients with SAB in the setting of a CIED infection are classified as complicated SAB and they should receive 4 to 6 weeks of antimicrobial Therapy

Timing of Device Replacement One-third to one-half of patients may not require a new CIED implantation

Reimplantation of New PPM/ICD

Question 70 y m presented with SAB with a CIED for three years who do not have clinical evidence of generator-site infection, lead vegetation, or valve vegetation .what are the chances that he has CIED infection 10% 25% 50% 100%

Staph Aureus Bacteremia The management of S aureus bacteremia (SAB) among patients with a CIED who don ot have clinical evidence of generator-site infection, lead vegetation, or valve vegetation remains challenging. Prospective studies suggest the incidence of CIED infection may be as high as 45% in patients with SAB. (Staphylococcus aureus bacteremiain patients with permanent pacemakers or implantable cardioverter-defibrillators.Circulation 2001)

Certain clinical scenarios increase the probability of CIED infection 1.SAB without another identified source. 2.Recurrent SAB 3.Persistent bacteremia (24 hours) 4.Presenceof a prosthetic valve. 5. Presence of an ICD and bacteremia within 3months of device placement (Staphylococcus aureus bacteremia in patients with permanent pacemakers or implantable cardioverter-defibrillators. Circulation 2001)

Gram-negative bacteremia Only 6% of patients had either definite or possible CIED infection. No patients seemed to have secondary hematogenous seeding of the system. Device extraction in the setting of gram-negative bacteremia is not recommended without clinical or echocardiographic evidence of CIED infection unless bacteremia is persistent or relapses withthout another defined focus of infection (Update on cardiovascular implantableelectronic device infections and their management: a scientific statementfrom the American Heart Association. Circulation 2010)

PREVENTION Antimicrobial prophylaxis reduces the risk of CIED infection antimicrobial prophylaxis in the postoperative period is currently not recommended. The antibacterial envelope is a polymer mesh that releases rifampin and minocycline after implantation. Nearly half the patients (49%)in this study had at least three established risk factors for development of CIED infection, but there was a low rate of infection (<0.50%)

Take Home Lessons 1.CIED infections are an increasing problem associated with high morbidity and mortality. 2.Major risk factors for CIED infection include renal insufficiency, presence of indwelling catheters, diabetes mellitus, and corticosteroid use. 3.Staphylococcus spp are the most common pathogen, whereas gram-negative bacteria are rarely implicated. .

4.Blood cultures, generator pocket tissue cultures, lead tip cultures, and echocardiography are key aspects of the diagnostic work-up for suspected CIED infection. 5. Complete removal of all hardware is strongly recommended, along with adjunctive antimicrobial therapy. Patient is at extremely high risk of peri procedural complications or has limited life expectancy. In such cases, chronic suppressive antimicrobial treatment may be preferred

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