Wilkoff, Bruce L. MD*
Infectious disease physicians, nurses, hospital epidemiologists, clinical microbiologists, pharmacists, public health authorities, practicing physicians, and other healthcare professionals interested in the treatment of serious infections due to methicillin-resistant Staphylococcus aureus (MRSA).
Outline the patient care pathway for patients with pacemaker or implantable cardioverter defibrillator (ICD) infection, including transvenous lead extraction and device reimplantation; describe the role of surgery in the management of endocarditis in the setting of an implantable electronic cardiac device.
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Credit is based on the approximate time it should take to read this publication and complete the assessment and evaluation. A minimum assessment score of 80% is required. Publication date is November 1, 2011. Requests for credit or contact hours must be postmarked no later than May 1, 2012, after which this material is no longer certified for credit.
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Marla Dalton, PE (managing editor), reported no relevant financial relationships.
Barbara DeBaun, RN (reviewer), reported no relevant financial relationships.
Thomas M. File, Jr, MD (reviewer), served as an advisor or consultant for Astellas/Theravance, Cerexa/Forest, Daiichi Sankyo, GSK, Merck, Nabriva, Pfizer Inc, and Tetraphase; and received grants for clinical research from Cempra, Pfizer Inc, and The Medicines Company.
Marguerite Jackson, PhD, RN (reviewer), reported no relevant financial relationships.
Donna Mazyck, RN (reviewer), reported no relevant financial relationships.
Susan J. Rehm, MD (senior editor), served as an advisor or consultant for Merck and Pfizer, Inc; served as a speaker for Genentech; and received grants for clinical research from Cubist Pharmaceuticals, Inc.
Bruce L. Wilkoff, MD (faculty), reported no relevant financial relationships.
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DIAGNOSING A DEVICE INFECTION
Infection of an implanted device is quite a difficult diagnosis to make. Signs and symptoms may or may not be apparent. In Figure 1, a patient presented with dimpling of the skin, slight erythema, distortion of the skin, and fat necrosis, which are clues to an active infection. In the infection shown in Figure 2, physicians attempted to revise the pocket and the leads and then reimplanted them. The conservative approach in this patient resulted in disfiguration and persistent infection.
Infections can also be quite subtle. In a scanning electron micrograph in Figure 3, bacteria can be seen on higher-power magnification. The wires in the micrograph that conduct the electricity down to the heart are inside a plastic tube. This patient did not present with typical symptoms of infection such as dimpling of the skin, endocarditis, or apparent vegetations. In this case, the inside of the lead is a perfect protected environment for bacteria because antibiotics cannot penetrate inside the lead.
MANAGING DEVICE INFECTIONS AND LEAD EXTRACTIONS
An algorithmic approach to managing device infection was proposed by Chua et al2 in a study of 123 patients with infections involving cardiovascular implantable electronic devices (CIED) (between January 1995 and August 1998). The algorithm approach included the following steps:
1. Complete explantation, debridement, and primary pocket closure.
2. For patients who are pacer dependent, use an active fixation temporary pacemaker until device reimplantation.
3. Culture the blood, the pocket, and the lead tips, and then tailor the antibiotic therapy according to the results.
4. Reimplant the device at a different location at least 36 hours after the extraction if the patient is afebrile, cellulitis has resolved, and results of blood cultures are negative.
5. Discharge the patient after placement of a peripherally inserted central catheter (PICC) or other venous device with outpatient parenteral antibiotic therapy. In select cases, oral antibiotics can be used.
In the Chua study, of 123 patients, there were 87 pacemaker infections and 36 defibrillator infections. The mean age of the patients was 66 years; 71% were men. The mean interval to onset of symptoms from the last surgery was 96 weeks (range, 0-806 weeks). Complete extraction was performed in 118 patients (96%). Relapse occurred in 4 patients (3%) as a result of lapse in protocol. In the first case, the epicardial patch was retained although all of the transvenous leads were removed. In the second patient, the pacemaker lead was retained and the defibrillator and leads had been removed from one side. In the third case, reimplantation occurred with the same procedure on the same side. In the fourth case, there was incomplete epicardial lead removal. The authors concluded that successful reimplantation in a remote anatomic site occurred in patients after compete removal of implantable physiologic devices and antimicrobial therapy; patients incurred low mortality and recurrent infection rates.
The outcome of patients undergoing extraction of infected CIEDs was described in a retrospective review of 412 patients from January 2002 to March 2007 at the Cleveland Clinic.3 The mean age of the patient population was 68 years; 74% were male. The patients had a number of comorbidities including coronary artery disease (56%), congestive heart failure (46%), diabetes (30%), renal failure (25%), end-stage renal disease on dialysis (5%), coronary artery bypass graft (30%), and percutaneous coronary intervention (15%). In this population, there were 53% permanent pacemakers, 31% implantable defibrillators, and 16% cardiac resynchronization devices, either pacemakers or defibrillators.
Only 2% of the patients had persistent bacteremia; 59% had localized signs and symptoms, and 39% had systemic signs and symptoms with an intact pocket. Localized signs and symptoms occurred at similar rates: erythema (41%), swelling (38%), tenderness (28%), drainage (38%), and erosion (21%). Of the patients with only localized signs and symptoms, negative blood cultures occurred in 81% and positive blood cultures in 19%. The percentage of patients who experienced systemic signs and symptoms including fever, chills, and malaise were 45%, 43%, and 28%, respectively. Of the patients who experienced systemic signs and symptoms, 91% had positive blood cultures and 9% had negative blood cultures.
Of the 412 patients, negative, monomicrobial, and polymicrobial cultures occurred in 12%, 78%, and 10% of patients, respectively. The source of the positive cultures came from the pocket tissue (44%), blood (49%), and the lead tip (54%). Most of the pathogens were gram-positive (88%); 9% were gram-negative, 2% were anaerobes, 0.5% were fungi, and 0.5% were other organisms. Of the 414 pathogens, 331 were staphylococci,and 162 (49%) were methicillin-resistant. Among the 331 staphylococcal isolates, the proportions of methicillin-resistant Staphylococcus aureus (MRSA, 20%), methicillin-resistant Staphylococcus epidermidis (MRSE, 30%), methicillin-susceptible S. aureus (MSSA, 25%) and methicillin-susceptible S. epidermidis (MSSE, 25%) were equally divided.
Reimplantation occurred during the same hospitalization in 59% of the patients. Reimplantation did not occur in 33% of patients. Some patients (4%) were transferred to another facility and the device was retained in 4% of the patients. The patients who had reimplantation during the same hospital stay (n = 235) were followed up after 1 year. Six (2.5%) of these patients presented with infection. Five of these 6 patients had systemic symptoms and positive blood cultures as the original presentation.
TRANSVENOUS LEAD EXTRACTIONS
Wilkoff et al5 have presented updated recommendations on transvenous lead extractions4 and techniques for addressing lead removal and extraction. An important point is that not every lead removal is a lead extraction. The definition of a lead removal is the removal of a pacing or defibrillator lead using any technique. Lead explantation is the removal of a lead using simple traction techniques (eg, no locking stylet, telescoping sheaths, or femoral extraction tools). Lead extraction is removal of a lead that has been implanted for more than 1 year, or a lead regardless of duration of implant requiring the assistance of specialized equipment that is not included as part of the typical implant package, and/or removal of a lead from a route other than via the implant vein. Implantable cardioverter-defibrillator (ICD) leads may require specialized extraction equipment even when implantation duration is less than 1 year.
Figure 4 shows a defibrillator lead that was taken out of the right ventricle. The fibrosis is dense and can grow inside of the loops of the defibrillator coil. The key resource that the physician has in removing leads is the tensile strength of the lead. To improve the tensile strength of the leads, a locking stylet is used and is placed at the tip of the lead. The locking stylet locks at the tip, and, when pulled, the lead can be removed.
Another tool that is used for extraction is a countertraction sheath with telescoping layers or sheaths (Fig. 5). The inner sheath provides more flexibility in maneuvering around the curves of the lead as it goes through the vein, and the outer sheath provides more stiffness and pushing ability of the sheaths.
The process of extracting these leads involves pulling on the locking stylet and pushing on the sheaths to break up the encapsulating tissue (Fig. 6). As the inner sheath is approaching the encapsulating tissue, it is important to pull gently on the locking stylet so that it does not rip the lead out. Similarly, it is just as important to not push so hard on the sheath that it advances the lead into the vein. Instead, the objective is to slowly disrupt the encapsulating tissue, allowing the sheath to cover the lead all the way down to the heart.
Another extraction technique is called countertraction. The sheaths should be placed down over the leads, almost to the right ventricular apex or the right atrium, approximately 1 to 2 mm before the tip is reached. The sheath is held and the locking stylet is pulled, pulling the lead into the sheath. This procedure pushes the last bit of fibrosis off the end of the lead and leaves it in the heart. This allows the lead to be extracted without tearing the ventricle or atrial tissue.
More advanced sheaths (eg, the laser sheath) may be used to help break through the fibrosis. Mechanical dilators have a bit at the end (Fig. 7). Upon gripping the handle, the metal tip rotates and bores through the fibrosis. If the leads have already been cut and they cannot be pulled out from above, the locking stylet would not be an appropriate option. In this case, the sheath is placed from the femoral vein and advanced up the iliac vein to the inferior vena cava, and up into the atrium. The lead can then be extracted from this position. There are several tools that can be used inside the heart to grasp onto the lead. In Figure 8, the lead is pulled into a Dotter basket with a tip deflecting wire.
The safety of transvenous lead extraction has been documented by the team at the Cleveland Clinic. The data in Table 1 represent data from 15 physicians. From 2001 through 2007, the average number of extraction procedures was 308, with an average of 540 leads extracted each year. Clinical success averaged 99.38%, and the percentage of major complications (ie, death and/or major internal bleeding) was 0.33%.
The LExICon Study
The Lead Extraction in the Contemporary Setting (LExICon) Study conducted by Wazni et al6 evaluated the safety and efficacy of laser-assisted lead extraction in 1449 consecutive patients who underwent laser-assisted lead extraction between January 2004 and December 2007. A total of 2405 leads were extracted at 13 clinical sites (20-270 procedures at each site). The reasons for extraction were infection (57%), functional, abandoned leads (27%), nonfunctional leads (11%), venous stenosis or occlusion (4.5%), or chronic pain at the device or insertion site (0.8%).
There were differences between patients with device-related endocarditis (DRE) and those without device-related endocarditis (Non-DRE). There were statistical differences between the groups in mean age (66 vs. 62 years; P < 0.0001), ejection fraction less than or equal to 30% (39% vs. 61%; P = 0.0006), diabetes (39% vs. 23%; P < 0.0001), renal failure with creatinine greater than or equal to 2.0 mg/dL (24% vs. 7%; P < 0.0001), and hospital death (4% vs. <1%; P < 0.0001). There was no difference between groups in sex, clinical success, and procedure-related major adverse events. Overall, hospital mortality was 1.86%, the noninfection rate was 0.3%, the non-DRE infection rate was 1.7%, and the DRE rate was 4.3%.
Patients with DRE and diabetes had a higher mortality rate than patients without diabetes (8% vs. 2%; P < 0.0075). Similarly, patients with DRE and renal insufficiency (creatinine ≥2.0 mg/dL) had a higher mortality rate than patients with DRE without renal insufficiency (12% vs. 2%; P < 0.0001). The authors concluded that, overall, lead extraction using laser sheaths was a highly successful procedure with few complications.
Indications for Transvenous Lead Extraction
The Heart Rhythm Society expert consensus group classified its recommendations as follows:4
Class I: conditions for which there is evidence and/or general agreement that a given procedure or treatment is useful and effective.
Class II: conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of a procedure or treatment.
Class III: Conditions for which there is evidence and/or general agreement that the procedure/treatment is not useful or effective and, in some cases, may be harmful.
The indications for transvenous lead extraction apply only to those patients in whom the benefits of lead removal outweigh the risks when assessed based on individualized patient factors and operator-specific experience and outcomes.4
Class I indications refer to the situation in which complete device and lead removal is recommended in all patients with a definite CIED system infection:
1. Valvular endocarditis, lead endocarditis, or sepsis.
2. CIED pocket infection as evidenced by pocket abscess, device erosion, skin adherence, or chronic draining sinus without clinically evident involvement of the transvenous portion of the lead system.
3. Valvular endocarditis without definite involvement of the lead(s) and/or device.
4. Occult gram-positive bacteremia.
Class II indications are present and complete device and lead removal is reasonable in patients with:
1. Persistent occult gram-negative bacteremia.
Class III indications refer to the situations when CIED removal is not indicated:
1. Superficial or incisional infection without involvement of the device and/or leads.
2. Chronic bacteremia due to a source other than the CIED, when long-term suppressive antibiotic therapy is required.
Principles for CIED replacement after removal of infected device include the following:
1. Each patient should be carefully evaluated to determine if there is a continued need for a new CIED.
2. The replacement device implantation should not be ipsilateral to the extraction site (eg, contralateral side, ileac vein, and transatrial and epicardial implantation).
1. Among patients with positive preoperative blood cultures, positive lead tip cultures, or preoperative sepsis and positive blood cultures, a new CIED system can be implanted when there is no further clinical evidence of systemic infection and the blood cultures drawn within 24 hours of CIED system removal remain negative for at least 72 hours.
2. It is reasonable to delay transvenous reimplantation of a new CIED system for at least 14 days if the patient had valvular or lead-associated vegetations. Debridement of the vegetations or implantation of epicardial leads may allow earlier CIED system reimplantation.
In summary, once a diagnosis of an infected implanted device has been made, appropriate and timely treatment and management of the infection is critical. When specific algorithms and management guidelines are followed with regard to lead extraction and reimplantation of a device, morbidity and mortality may be reduced in these patients. Lead extraction has proven to be a safe procedure with few complications when using the proper techniques; however, patients with DRE, especially in the setting of diabetes and renal failure, may have higher mortality rates in laser-assisted lead extraction procedures.
1. Ellenbogen KA, Wilkoff BL, Kay GN, et al. Clinical Cardiac Pacing, Defibrillation and Resynchronization Therapy, ed 4. Philadelphia, PA: Saunders; 2011.
2. Chua JD, Wilkoff BL, Lee I, et al. Diagnosis and management of infections involving implantable electrophysiologic cardiac devices. Ann Intern Med. 2000;133(8):604-608.
3. Tarakji KG, Chan EJ, Cantillon DJ, et al. Cardiac implantable electronic device infections: presentation, management, and patient outcomes. Heart Rhythm. 2010;7:1043-1047.
4. Wilkoff BL, Love CJ, Byrd CL, et al. Transvenous lead extraction: Heart Rhythm Society expert consensus on facilities, training, indications, and patient management. Heart Rhythm. 2009;6(7):1085-1104.
5. Rickard J, Wilkoff BL. Extraction of implantable cardiac devices. Curr Cardiol Rep. 2011;13(5):407-414.
6. Wazni O, Epstein LM, Carrillo RG, et al. Lead extraction in the contemporary setting: the LExICon study. J Am Coll Cardiol. 2010;55(6):579-586.
A minimum assessment score of 80% is required.
1) The algorithm used in the Chua et al study included the following steps:
a. Reimplant the device at a different location at least 24 hours after the extraction.
b. Culture the blood, the pocket, and the lead tips, and then guide the antibiotic therapy according to the results.
c. Defer pacemaker insertion until blood cultures are negative.
d. Partial explantation, debridement, and primary pocket closure will suffice.
2) Most pathogens reported in the cultures of 412 patients undergoing extraction of infected cardiovascular implantable electronic devices in the Tarakji et al study were:
c. Gram-negative organisms
d. Gram-positive organisms
3) Which of the following definitions describes lead extraction?
a. the removal of a lead using simple traction techniques
b. the removal of a pacing or defibrillator lead using any technique
c. the removal of a lead that has been implanted for more than 1 year
d. the removal of a lead from a route via the implant vein.
4) The LExICon study (Wazni et al) concluded that:
a. Lead extraction via laser sheaths is marginally successful with a high procedural complication rate.
b. Total mortality with lead extraction procedures is substantially increased in patients with device-related endocarditis, particularly in those with diabetes or renal insufficiency.
c. Overall, hospital mortality and infection rates were high with the laser-assisted lead extraction procedure.
d. The number of procedure-related major adverse events was higher in patients with device-related endocarditis.
5) Which of the following is NOT a Class I indication for transvenous lead extraction?
a. Valvular endocarditis without definite involvement of the lead(s) and/or device.
b. Valvular endocarditis, lead endocarditis, or sepsis.
c. CIED pocket infection as evidenced by pocket abscess, device erosion, skin adherence, or chronic draining sinus without clinically evident involvement of the transvenous portion of the lead system.
d. Occult gram-negative bacteremia
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