roughly 40 years have passed since permanent pacemakers ( pms ) became available in clinical medicine .
more recently , implantable cardioverter - defibrillators ( icds ) and cardiac resynchronization therapy ( crt ) have been introduced .
the rate of device implantation is increasing with the aging of the general population and the indications are expanding .
similar to other prosthetic materials , infections complicate a small proportion of patients with these devices . with the increase in device implantation
we introduced the excimer laser system in 2009 for the transvenous removal of the implanted leads .
however , there have been few reports , ,   concerning the management of cardiac device infections .
the purpose of this study was to review our single center experience and to clarify the current status of cardiac implantable electronic device ( cied ) infections in japan .
all 183 patients with cied infections who underwent a device and transvenous lead removal using an excimer laser system in kokura memorial hospital from july 2009 through march 2014 were reviewed .
briefly , a pocket infection was defined as the presence of local warmth , erythema , swelling , edema , pain , or discharge from the device pocket , or an erosion or impending erosion of the device .
blood cultures were obtained from all patients on the day of admission ; cultures were also obtained from the generator and the tip of the lead at the time of device removal .
the indications for a lead extraction were decided based on the heart rhythm society expert consensus statement .
the baseline clinical characteristics , pathogens , results of the lead extraction procedures , and follow - up results were analyzed .
the procedures were performed in the cardiac catheterization laboratory or operation room under general or venous anesthesia according to the patient s condition .
careful monitoring with surface electrocardiograms , invasive arterial blood pressure monitoring , and transesophageal or intracardiac echocardiography were performed in all patients .
briefly , the lead was prepared by inserting a locking stylet into the inner coil lumen when possible .
a laser application was performed at binding sites and the laser sheath was gradually advanced from one binding site to another until the tip of the lead was reached . once abutting the myocardium ,
a combination of traction and counter - traction was performed and the lead was freed .
complete procedural success was defined as the  removal of all targeted leads and all lead material from the vascular space , with the absence of any permanently disabling complications or procedure - related deaths .
 clinical success was defined as the  removal of all targeted leads and lead material from the vascular space , or retention of a small portion of the lead that did not negatively impact the outcome goals of the procedure .
 failure was defined as the  inability to achieve either complete procedural or clinical success , or the development of any permanently disabling complications or procedure - related deaths . 
major complications were defined as  any of the outcomes related to the procedure that were life threatening or resulted in death , and in addition , any unexpected events that caused a persistent or significant disability , or any events that required a significant surgical intervention to prevent any of the outcomes listed above .
 minor complications were defined as  any undesired events related to the procedure that required a medical intervention or minor procedural intervention to remedy , and did not persistently or significantly limit the patient s function , nor threaten their life or cause death  .
the continuous variables are expressed as the meansd and were compared using a student s t - test .
all 183 patients with cied infections who underwent a device and transvenous lead removal using an excimer laser system in kokura memorial hospital from july 2009 through march 2014 were reviewed .
briefly , a pocket infection was defined as the presence of local warmth , erythema , swelling , edema , pain , or discharge from the device pocket , or an erosion or impending erosion of the device .
blood cultures were obtained from all patients on the day of admission ; cultures were also obtained from the generator and the tip of the lead at the time of device removal .
the indications for a lead extraction were decided based on the heart rhythm society expert consensus statement .
the baseline clinical characteristics , pathogens , results of the lead extraction procedures , and follow - up results were analyzed .
the procedures were performed in the cardiac catheterization laboratory or operation room under general or venous anesthesia according to the patient s condition .
careful monitoring with surface electrocardiograms , invasive arterial blood pressure monitoring , and transesophageal or intracardiac echocardiography were performed in all patients .
briefly , the lead was prepared by inserting a locking stylet into the inner coil lumen when possible .
a laser application was performed at binding sites and the laser sheath was gradually advanced from one binding site to another until the tip of the lead was reached . once abutting the myocardium ,
a combination of traction and counter - traction was performed and the lead was freed .
complete procedural success was defined as the  removal of all targeted leads and all lead material from the vascular space , with the absence of any permanently disabling complications or procedure - related deaths .
 clinical success was defined as the  removal of all targeted leads and lead material from the vascular space , or retention of a small portion of the lead that did not negatively impact the outcome goals of the procedure .
 failure was defined as the  inability to achieve either complete procedural or clinical success , or the development of any permanently disabling complications or procedure - related deaths .
 major complications were defined as  any of the outcomes related to the procedure that were life threatening or resulted in death , and in addition , any unexpected events that caused a persistent or significant disability , or any events that required a significant surgical intervention to prevent any of the outcomes listed above .
 minor complications were defined as  any undesired events related to the procedure that required a medical intervention or minor procedural intervention to remedy , and did not persistently or significantly limit the patient s function , nor threaten their life or cause death  .
the continuous variables are expressed as the meansd and were compared using a student s t - test .
two hundred twenty - two lead extraction procedures were performed between july 2009 and march 2014 .
one hundred eighty - three patients ( mean 72.214.3 years old , 131 males ) had explantations of the devices , leads , or both due to infection complications .
one hundred twenty patients ( 65.6% ) presented with signs and symptoms of an infection involving the device pocket without the presentation of an endovascular infection .
twenty - six of 63 patients were diagnosed with infectious endocarditis according to duke s criteria . among this cohort ,
136 patients ( 74.3% ) had a permanent pm , 45 ( 24.6% ) had an icd , and 19 ( 10.4% ) had a biventricular pm with or without an icd .
the mean duration of the device implant and device explantation ranged from 2 to 417 months ( 91.983.7 months ) .
the mean duration of the implantation or last device replacement and device explantation was 30.536.2 months .
twenty - seven patients ( 14.8% ) had an early explantation ( <3 months ) , 45 ( 24.6% ) had a late explantation ( 412 months ) , and 111 ( 60.7% ) had a delayed explantation ( > 12 months ) .
eighty ( 43.7% ) patients underwent a device explantation due to a late infection more than 24 months after the device - related procedure .
eighty - seven patients ( 47.5% ) had a previous surgical intervention without full removal of all the hardware .
twenty - two patients received a device implantation on the ipsilateral side even though the infection was active in the pm pocket .
one to five leads were implanted in each patient , and a total of 450 leads were extracted .
twenty - five leads were extracted by manual traction ; the remaining leads were extracted using an excimer laser sheath .
the summary data of the extracted leads are shown in table 2 . among the 450 leads extracted ,
the positions of the leads were the right atrium ( n=170 , 37.8% ) , coronary sinus ( n=20 , 4.4% ) , and right ventricle ( n=260 , 57.8% ) , and included 79 icd leads .
the mean implant duration was 88.577.6 months in total , with 92.376.4 months in the right atrium , 34.927.6 months in the coronary sinus , and 102.590.1 months in the right ventricle ; 62.4 35.5 were icd leads table 3 .
complete procedural success was achieved with 437 leads ( 97.1% ) , while partial removal in nine ( 2.0% ) , and failure with four leads ( 0.9% ) occurred .
the mean implant duration of complete and partial removals was 86.175.9 months and 162.0101.0 months , respectively ( p<0.01 ) . in all cases of partial removal ,
only the tip of the lead remained in the myocardium without any complications and the desired clinical outcomes could be achieved . in two patients , open heart surgery
the proximal portion of the leads was extracted using an excimer laser sheath from the pm pocket . with another four leads in two patients ,
the leads were also removed during open heart surgery due to cardiac tamponade encountered during the lead extraction procedure .
major complications directly related to the lead extraction procedure occurred in five patients ( 2.7% , cardiac tamponade in four , and death within 24  h after the procedure due to uncontrollable bleeding from the vein in one patient ) .
further , minor adverse events occurred in seven more patients ( 3.8% , pneumothorax in two , blood transfusion in four , and pulmonary embolism in one patient ) .
two patients died because the systemic infection could not be controlled even after the removal of all implanted devices .
one patient died during the hospital stay because of a cerebral infarction not related to the extraction procedure .
fifteen of 183 patients ( 8.2% ) did not require further device therapy , and devices were implanted in the remaining patients .
eight of these patients were transferred to another hospital for the re - implantation procedure .
two patients had recurrences of infection within one year after the explantation of the devices .
2 ) and staphylococcus aureus ( 37.1% ) were the most common causes of cied infections followed by the corynebacterium species ( eight patients ) . gram - negative bacilli including pseudomonas aeruginosa ( three patients ) , escherichia coli ( two patients ) , and proteus mirabilis were the pathogens in 3.8% .
seven patients had an anaerobic gram - positive bacillus species and two patients had a fungal ( candida albicans ) infection .
thirty - three ( 18% ) patients had localized inflammatory signs in the generator pocket or an erosion of the device / lead , but the cultures were negative .
two hundred twenty - two lead extraction procedures were performed between july 2009 and march 2014 .
one hundred eighty - three patients ( mean 72.214.3 years old , 131 males ) had explantations of the devices , leads , or both due to infection complications .
one hundred twenty patients ( 65.6% ) presented with signs and symptoms of an infection involving the device pocket without the presentation of an endovascular infection .
twenty - six of 63 patients were diagnosed with infectious endocarditis according to duke s criteria . among this cohort ,
136 patients ( 74.3% ) had a permanent pm , 45 ( 24.6% ) had an icd , and 19 ( 10.4% ) had a biventricular pm with or without an icd .
the mean duration of the device implant and device explantation ranged from 2 to 417 months ( 91.983.7 months ) .
the mean duration of the implantation or last device replacement and device explantation was 30.536.2 months .
twenty - seven patients ( 14.8% ) had an early explantation ( <3 months ) , 45 ( 24.6% ) had a late explantation ( 412 months ) , and 111 ( 60.7% ) had a delayed explantation ( > 12 months ) .
eighty ( 43.7% ) patients underwent a device explantation due to a late infection more than 24 months after the device - related procedure .
eighty - seven patients ( 47.5% ) had a previous surgical intervention without full removal of all the hardware .
twenty - two patients received a device implantation on the ipsilateral side even though the infection was active in the pm pocket .
one to five leads were implanted in each patient , and a total of 450 leads were extracted .
twenty - five leads were extracted by manual traction ; the remaining leads were extracted using an excimer laser sheath .
the summary data of the extracted leads are shown in table 2 . among the 450 leads extracted ,
the positions of the leads were the right atrium ( n=170 , 37.8% ) , coronary sinus ( n=20 , 4.4% ) , and right ventricle ( n=260 , 57.8% ) , and included 79 icd leads .
the mean implant duration was 88.577.6 months in total , with 92.376.4 months in the right atrium , 34.927.6 months in the coronary sinus , and 102.590.1 months in the right ventricle ; 62.4 35.5 were icd leads table 3 .
complete procedural success was achieved with 437 leads ( 97.1% ) , while partial removal in nine ( 2.0% ) , and failure with four leads ( 0.9% ) occurred .
the mean implant duration of complete and partial removals was 86.175.9 months and 162.0101.0 months , respectively ( p<0.01 ) . in all cases of partial removal ,
only the tip of the lead remained in the myocardium without any complications and the desired clinical outcomes could be achieved . in two patients , open heart surgery
the proximal portion of the leads was extracted using an excimer laser sheath from the pm pocket . with another four leads in two patients ,
the leads were also removed during open heart surgery due to cardiac tamponade encountered during the lead extraction procedure .
major complications directly related to the lead extraction procedure occurred in five patients ( 2.7% , cardiac tamponade in four , and death within 24  h after the procedure due to uncontrollable bleeding from the vein in one patient ) .
further , minor adverse events occurred in seven more patients ( 3.8% , pneumothorax in two , blood transfusion in four , and pulmonary embolism in one patient ) .
two patients died because the systemic infection could not be controlled even after the removal of all implanted devices .
one patient died during the hospital stay because of a cerebral infarction not related to the extraction procedure .
fifteen of 183 patients ( 8.2% ) did not require further device therapy , and devices were implanted in the remaining patients .
eight of these patients were transferred to another hospital for the re - implantation procedure .
two patients had recurrences of infection within one year after the explantation of the devices .
2 ) and staphylococcus aureus ( 37.1% ) were the most common causes of cied infections followed by the corynebacterium species ( eight patients ) . gram - negative bacilli including pseudomonas aeruginosa ( three patients ) , escherichia coli ( two patients ) , and proteus mirabilis were the pathogens in 3.8% .
seven patients had an anaerobic gram - positive bacillus species and two patients had a fungal ( candida albicans ) infection .
thirty - three ( 18% ) patients had localized inflammatory signs in the generator pocket or an erosion of the device / lead , but the cultures were negative .
the rate of device implantation is increasing with the aging of the general population and the expanding indications .
voigt et al .   reported that the rate of hospitalization for cied infections have increased faster than the rate of cied implants .
this disproportionate increase is consistent with the findings of cabell and colleagues   who demonstrated accelerating rates of cardiac device infections ( including cieds , prosthetic valves , and ventricular assist devices ) among medicare beneficiaries from 1990 to 1999 .
first , while the age has remained relatively constant , there has been an increase in the prevalence of a coexistent morbidity in cied recipients .
uslan et al .   have shown that population - adjusted pm implantation incidences have increased and that there has been an age - independent rise in comorbidities in pm recipients .
second , voigt et al . speculated that a widespread and potentially indiscriminate cied utilization for primary prevention of sudden cardiac death and the treatment of heart failure might play a role , primarily due to the disadvantaged health status and prevalent comorbidities of such recipients .
particularly , given the adverse impact of such comorbidities on the crt response , a move to a more judicious application of cieds , in general , may be warranted .
interestingly a dramatic rise in cied infections occurred beginning in 2001 and 2002 , when the positive results of the primary prevention defibrillator trials ,   were accepted by the medical community , followed by the adoption and increased rate of crt device implantations .
reported a case of a thoracoscopy - guided lead extraction with an excimer laser sheath and okada et al .   reported a case of a transjugular extraction using a snare technique
our current study consisted of 183 patients , the largest cohort in japan , and , therefore , this study can clarify the status of device infections and lead extractions in japan .
reported that device - related infections occurred in 0.68% of patients within the first year after the de novo implantation or replacement .
no data is available concerning the prevalence of cied infections in japan , however at kokura memorial hospital , 1855 cieds were implanted between 2008 and 2012 ( de novo implantations in 1,174 and replacements or upgrades in 681 patients ) .
this data suggests that the prevalence of cied infections seems to be similar in japan . as for the management of cied infections ,
the recommendations for a complete extraction of the device , route of administration , duration of antimicrobial therapy , and the timing of the placement of a new device are based on observational data and clinical experience .
observations from several medical centers universally support the complete removal of the device to cure the infection and reduce morbidity and mortality , , .
the relapse rate when a complete device removal is performed is 04.2% . on the contrary ,
when a partial removal or antibiotics are chosen , the relapse rate increases to 50100% , , , , , .
of the 183 cied infection patients , 27 ( 14.8% ) had an early infection ( <3 months after the procedure ) , 45 ( 24.6% ) had a late infection ( 412 months after the device - related procedure ) , and 111 ( 60.7% ) had a delayed infection ( more than 12 months after the procedure ) .
of interest , 60 ( 43.7% ) patients presented with an infection after an interval of more than 24 months after the device - related procedure .
as previously mentioned , almost half of the patients in this study had a previous surgical intervention without a full removal of all hardware and one - fourth of the patients underwent device implantation on the ipsilateral side even though the infection was active in the pm pocket .
this might suggest a considerable number of patients were undertreated in japan and at a risk of recurring infections , endocarditis , or fatal results .
complete procedure success was achieved in 97.1% of the lead extractions in our study while partial removal occurred in 2.0% , and failure in 0.9% .
okamura et al .   reported the success rate of a complete removal was 97.1% .
these two results were almost equally beneficial with those of the lexicon study ( complete removal : 96.5% ) .
the mean implant duration of the partially removed leads was 162101 months ( longest 338 months ) .
roux et al .   reported that a longer time from the implantation independently predicted a procedural failure . in this patient group ,
the mean implant duration of complete and partial removals was 86.175.9 months and 162.0101.0 months , respectively ( p<0.01 ) . in our study , culture results were positive for staphylococcus aureus in 37.1% of the patients , cns in 30.1% , and other bacterial species in 14.8% .
tarakji et al .   reported their pathogens of cied infections were cns in 44.4% of the patients , methicillin - sensitive s. aureus ( mssa ) in 20.1% , and methicillin - resistant s. aureus ( mrsa ) in 15.8% .
our data and previously published data suggest that the staphylococcus species continues to represent the most common pathogen of cied infections , with 510% being methicillin resistant .
the usefulness of the prophylactic use of antibiotics at the time of a device implantation was reported by de oliveira et al .  
therefore many institutions continue to use beta - lactam antimicrobial agents at the time of implantation ; however , this is not effective against methicillin - resistant organisms . a single dose of vancomycin before the implantation might be better than that of beta - lactam antibiotics to prevent cied infections in the selected patients such as mrsa carrier .
two patients in this patient group ( 1.1% ) had relapses within the first year .
one patient had a dual chamber icd due to ventricular tachycardia caused by a remote myocardial infarction .
the pocket infection reappeared after re - implantation of an icd on the ipsilateral side at a previous hospital .
the pathogen of the second infection was pseudomonas aeruginosa ; indicating that the second pocket infection might not have been a recurrence of the initial pocket infection .
the other patient had allergic dermatitis on the body and a vdd pm was implanted due to complete atrioventricular block .
that patient was referred to our hospital under a diagnosis of device - related endocarditis .
the device and all lead materials were completely removed and the patient underwent successful re - implantation of a device on the ipsilateral anterior chest after an intravenous antibiotic prescription for three weeks .
this patient , however , was readmitted due to bacteremia after re - implantation of the device . in our study ,
8.1% of the patients no longer required device implantation or had reasonable alternatives after their devices were removed .
thus , the need for re - implantation in patients with an infected device should be carefully evaluated .
ninety percent of our patients were initially treated by other institutions , and 47.5% had previously failed surgical attempts without a full removal .
further investigation with a larger patient group is required to clear up the present circumstances of cied infections in japan .
ninety percent of our patients were initially treated by other institutions , and 47.5% had previously failed surgical attempts without a full removal .
however , this report was a single center experience . further investigation with a larger patient group is required to clear up the present circumstances of cied infections in japan .
the current clinical status of cied infections seems to be similar in japan to that in foreign countries .
the optimal treatment of infected pm and implantable defibrillator devices involves the complete explantation of all hardware , followed by antibiotic therapy .
the excimer laser appeared to be safe and effective for extracting chronically implanted leads in japanese patients .
 backgroundlead extraction using laser sheaths is performed mainly for cardiac implantable electronic device ( cied ) infections . 
 however , there are few reports concerning the management of cied infections in japan.methods and resultslead extraction procedures were performed in 183 patients targeting 450 leads ( atrial leads : 170 , ventricular : 181 , implantable cardioverter - defibrillators ( icds ) : 79 , and coronary sinus : 20 ) . 
 one hundred twenty patients ( 65.6% ) presented with pocket infections without the presentation of an endovascular infection . 
 blood cultures were positive at least once in 63 patients ( 34.4% ) . 
 complete procedure success was achieved for 437 leads ( 97.1% ) while partial removal occurred in nine , and failure in four leads . 
 major complications directly related to the procedure occurred in five patients ( 2.7% ) . 
 two of the four patients with a cardiac tamponade required a surgical repair . 
 all patients received intravenous antibiotics , at least , one week after the procedure . 
 pocket or systemic infections were successfully controlled in 181 patients ( 98.9% ) . 
 coagulase - negative staphylococci ( 30.1% ) and staphylococcus aureus ( 37.1% ) were the most common causes of cied infections.conclusionthe current status of cied infections in japan seems to be similar to that previously reported from foreign countries . 
 the optimal treatment of cied infections involves the complete explantation of all hardware , followed by antibiotic therapy . 
Introduction
Material and methods
Study patients
Lead extraction procedure
Statistical analysis
Results
Baseline characteristics
Lead extraction procedure
Microbiology
Discussion
Limitations
Conclusions
Conflicts of interest