***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background —Transvenous pacemaker and defibrillator implantation is an exp and ing practice in pediatric and congenital heart disease patients , and given the finite longevity of current lead design s , lead extraction is an eventuality for a significant subset of these patients . Data on the safety and efficacy of different lead extraction techniques in this specific patient population are limited . Methods and Results —We report our experience from a single-center cohort study with a retrospective review of prospect ively collected data on all lead extraction s performed between January 2002 and December 2008 .  Lead extraction procedures involved a total of 144 patients and 203 leads . Of these , 61 patients ( 42 % ) were female and 86 ( 60 % ) had structural heart disease .  Successful simple extraction , requiring the use of only a nonlocking stylet , was achieved in 59 ( 29 % ) leads . Of the remaining leads , 35 were ab and oned and 109 underwent complex extraction techniques , including a radiofrequency-powered sheath used in 78 of 109 leads . Successful extraction was achieved in 80 % ( 162/203 ) of all leads and 94 % ( 103/109 ) of leads undergoing a complex extraction . On multivariable analysis , older lead age ( odds ratio [ OR ] , 0.63 ; 95 % confidence interval [ CI ] , 0.48 to 0.82 ; P<0.0001 ) , ventricular lead position ( OR , 0.40 ; 95 % CI , 0.20 to 0.79 ; P=0.015 ) , and polyurethane insulation ( OR , 0.34 ; 95 % CI , 0.14 to 0.80 ; P=0.017 ) were found to be associated with a decreased likelihood of simple extraction . There were 4 major and 4 minor procedural complications involving 8 patients and no procedure-related deaths . On univariate analysis , lead age ( OR , 1.28 ; 95 % CI , 1.09 to 1.50 ; P=0.002 ) was the only factor associated with procedural complications . Conclusions —The majority of leads implanted in pediatric and congenital heart disease patients can be extracted successfully ; however , the procedure carries a risk of serious complications . Older lead age , ventricular leads , and polyurethane insulation were independent predictors of the decreased likelihood of an extraction by simple traction BACKGROUND The aim of this study was to investigate whether transvenous lead removal is safe and effective in patients with lead vegetations greater than 1 cm in size . METHODS From 1991 to 2005 , a total of 53 patients underwent pacemaker or ICD lead removal for vegetations .  Transvenous lead removal using locking stylets and sheaths was performed in 30 patients ( 56.6 % ) and was found to be effective in 29 of those patients . In 1 patient , due to rupture of the lead , open heart removal of the ventricular lead remnant and tricuspid valve repair had to be performed due to persistent infection . In 23 of these patients , transesophageal echocardiography ( TEE ) verified vegetations greater than 1 cm in size . The remaining patients underwent primary lead removal using sternotomy and extracorporeal circulation ( ECC ) .  Pacemaker pocket infection was found in 16 patients ( 55.2 % ) of the transvenous study group and in 11 patients ( 45.8 % ) of the ECC group ( P = 0.72 ) . RESULTS Perioperative mortality was 5.7 % ( 3 patients ) ; all of them underwent primary ECC removal and had severe endocarditis of the tricuspid valve . None of the patients who underwent transvenous lead removal  died and there were no further complications such as pericardial tamponade or major pulmonary embolism requiring further interventions , even in patients demonstrating large vegetations . CONCLUSIONS This study demonstrates that transvenous lead removal is a safe and highly effective procedure for the removal of infected pacemaker and ICD leads , even in patients with large vegetations . Embolism to the lung proceeds mainly without further complications ; however , patients with vegetations that might obstruct a main stem of the pulmonary artery should undergo ECC removal BACKGROUND Lead extraction is increasingly necessary given the exponential growth in cardiac device implantation . Meanwhile , the tools , indications , and outcomes of this procedure continue to change . OBJECTIVE The purpose of this study was to examine contemporary indications , outcomes , and complications of transvenous lead extraction in a large series of patients at a high-volume lead extraction center . METHODS We performed a retrospective cohort study of consecutive patients undergoing lead extraction at a single , high-volume center . Patient and lead characteristics and the indications , outcomes , and need for laser assistance were analyzed . RESULTS From January 2000 to March 2007 , a total of 975 chronic endovascular leads were removed from 498 patients .  Median implant duration was 5.7 years ( range 0.5 - 32.7 years ) . Indications were infection ( 60.3 % ) , mechanical lead failure ( 29.3 % ) , and up grade of device system ( 8.8 % ) . Over the study period , lead malfunction decreased relative to other indications . Laser assistance for extraction was more likely with leads implanted longer than 3.4 years compared to less than 3.4 years ( odds ratio 6.15 , 95 % confidence interval 3.35 - 11.28 ) and with implantable cardioverter-defibrillator leads compared to pacemaker leads ( odds ratio 3.44 , 95 % confidence interval 1.84 - 6.43 ) . Overall , 97.5 % of the leads were completely removed . Major complications occurred in 2 ( 0.4 % ) patients . Only one patient required cardiac surgery . No deaths occurred . CONCLUSION In a high-volume center , lead extraction has a high success rate and low complication rate . Infection was the most common indication overall . Lead failure has decreased in relative proportion . Implantable cardioverter-defibrillator leads and longer lead implant time are associated with a requirement for laser lead extraction OBJECTIVES The purpose of this study was to evaluate the safety and effectiveness of pacemaker lead extraction with the excimer sheath in comparison to nonlaser lead extraction . BACKGROUND Fibrotic attachments that develop between chronically implanted pacemaker leads and to the venous , valvular and cardiac structures are the major obstacles to safe and consistent lead extraction . Locking stylets and telescoping sheaths produce a technically dem and ing but effective technique of mechanically disrupting the fibrosis . However , ultraviolet excimer laser light dissolves instead of tearing the tissue attachments . METHODS A r and omized trial of lead extraction was conducted in 301 patients with 465 chronically implanted pacemaker leads . The laser group patients had the leads removed with identical tools as the nonlaser group with the exception that the inner telescoping sheath was replaced with the 12-F excimer laser sheath . Success for both groups was defined as complete lead removal with the r and omized therapy without complications . RESULTS Complete lead removal rate was 94 % in the laser group and 64 % in the nonlaser group ( p = 0.001 ) . Failed nonlaser extraction was completed with the laser tools 88 % of the time . The mean time to achieve a successful lead extraction was significantly reduced for patients r and omized to the laser tools , 10.1 + /- 11.5 min compared with 12.9 + /- 19.2 min for patients r and omized to nonlaser techniques ( p < 0.04 ) . Potentially life-threatening complications occurred in none of the nonlaser and three of the laser patients , including one death ( p = NS ) . CONCLUSIONS Laser-assisted pacemaker lead extraction has significant clinical advantages over extraction without laser tools and is associated with significant risks BACKGROUND Cardiac resynchronization therapy ( CRT ) device and coronary sinus ( CS ) lead extraction are required due to the occurrence of systemic infection , malfunction , or up grade . Relevant research of CS lead extraction is rare , especially in developing countries because of the high cost and lack of specialized tools . We aim ed to evaluate percutaneous extraction of CS leads by modified conventional techniques . METHODS Of 200 patients referred for lead extraction from January 2007 to June 2011 , 24 ( 12.0 % ) involved CS leads ( 24 CS leads ) . We prospect ively analyzed clinical characteristics , optimized extraction techniques and feasibility of extraction . RESULTS Complete procedural success was achieved in 23 patients ( 95.8 % ) , and the clinical success in 24 patients ( 100.0 % ) . The leading indication for CS lead extraction  was infection ( 66.7 % ) . Mean implant duration was ( 29.5 ± 20.2 ) months ( range , 3 - 78 months ) . Sixteen CS leads ( 66.6 % ) were removed with locking stylets plus manual traction by superior transvenous approach . Mechanical dilatation and counter-traction was required to free fibrotic adhesions and extract 4 CS leads ( 16.7 % ) , which had longer implant duration than other leads ( ( 62.5 ± 12.3 ) vs. ( 22.9 ± 14.1 ) months , P < 0.05 ) . Another 4 CS ( 16.7 % ) leads were removed by modified and innovative snare techniques from femoral vein approach . Median extraction time was 11 minutes ( range , 3 - 61 minutes ) per CS lead , which had significant correlation with implant duration ( r = 0.8 , P < 0.001 ) . Sixteen patients ( 66.6 % ) were reimplanted with new devices at a median of 7.5 days after extraction . Median followed-up was 23.5 months ( range , 8 - 61 months ) , three patients died due to sudden cardiac death ( 26 months ) , heart failure ( 45 and 57 months , respectively ) . CONCLUSION The modified procedure was proved to be practical for percutaneous extraction of CS leads , especially in developing countries lacking expensive powered sheaths AIMS The aim of this study is to investigate the safety and effectiveness of Excimer laser-assisted lead extraction in Europe . The final European multi-centre study experience is presented . METHOD AND RESULTS The Excimer is a cool cutting laser ( 50 degrees C ) with a wavelength of 308 nm . The energy is emitted from the tip of a flexible sheath and is absorbed by proteins and lipids , 64 % of the energy is absorbed at a tissue depth of 0.06 mm . The sheath is positioned over the lead , and the fibrosis surrounding the lead is vaporized while advancing the sheath without damaging other leads . From August 1996 to March 2001 , 383 leads ( 170 atrial , 213 ventricular ) in 292 patients ( mean age 61.6 years , range 13 - 96 ) were extracted at 14 European centres . Mean implantation time was 74 months ( 3 - 358 ) . Most frequent indications were pocket infection ( 26 % ) , non-functional leads ( 21 % ) , patient morbidity ( 21 % ) , septicaemia or endocarditis ( 14 % ) , erosion ( 5 % ) , and lead interference ( 8 % ) . Median extraction time was 15 min ( 1 - 300 ) . Complete extraction was achieved in 90.9 % of the leads and partial extraction in 3.4 % . Extraction failed in 5.7 % of the leads . Major complications = perforations caused 10/22 ( 3.4/5.7 % ) of the failures . Most partially extracted patients were considered clinical ly successful , as only minor lead parts without clinical significance were left . Femoral non-laser technique was used to remove 8/12 of the non-complication failures . The total complication rate , including five minor complications ( 1.7 % ) , was 5.1 % . No in-hospital mortality occurred . CONCLUSION Pacing and implantable cardioverter-defibrillator leads can safely , effectively , and predictably be extracted . Open-heart extraction s can be limited to special cases . The results indicate that the traditional policy of ab and oning redundant leads , instead of removing them , may be obsolete in many patients AIMS Both electrosurgical dissection ( EDS ) and laser tools are effective in the extraction of chronic implanted endovascular leads . It is unclear which is superior . We undertook a retrospective single-centre study to assess this . METHODS AND RESULTS In our institution from 2000 to 2004 , all extraction s requiring an ablative sheath were performed using the EDS system .  In 2004 , an excimer laser system was acquired , which became the first choice . Consecutive patients undergoing extraction requiring an ablative sheath ( EDS or laser ) were studied . From 2000 to 2007 , 140 leads were extracted from 74 patients ( EDS 31 and laser 43 ) .  Procedural success was non-significantly higher in the laser vs. the EDS group ( 95 vs. 87 % ) . In the EDS group , one patient suffered tamponade requiring surgery ; in the laser group , one patient suffered a significant pericardial effusion treated conservatively . There were no deaths . Procedure and fluoroscopy times were similar between groups . More patients were referred for primary surgical extraction in the EDS vs. the laser era ( 7 vs. 0 , P = 0.003 
    Output:
    
RESULTS When meta-analyses were carried out separately for the studies with larger and smaller sample sizes , either using EHRA or Lexicon classification criteria , no clear differences emerged in the combined rate of major complications or intraoperative deaths .
In contrast , both minor complications and mortality at 30 days decreased as centre volume increased .
In our meta- analysis of observational studies , patients who have been treated in higher volume centres have a lower probability of minor complications and death at 30 days regardless of the infection rate , length of lead duration , type of device , and type of extraction