title: Early fatigue fractures in the IS-1 connector leg of a small-diameter ICD lead: value of returned product analysis for improving device safety.
abstract: BACKGROUND
  Conductor fractures may affect the performance of implantable cardioverter-defibrillator leads. During routine surveillance of returned product analyses (RPAs) in the Food and Drug Administration's Manufacturers and User Facility Device Experience database, we found a number of conductor fractures in small diameter implantable cardioverter-defibrillator leads manufactured by St Jude Medical, Inc (SJM, Sylmar, CA).
  
  
  OBJECTIVE
  To determine the location and cause of these fractures and to catalog their clinical signs and consequences.
  
  
  METHODS
  We searched the FDA's Manufacturers and User Facility Device Experience database on April 11, 2013. SJM provided information and data it collected independently.
  
  
  RESULTS
  Our search found 59 leads with fractures in the IS-1 leg. Most fractures were in leads implanted in 2008-2009; no fractures were found in leads implanted after 2010. Outer coil conductor fractures accounted for the majority (51 of 59, 86%). Oversensing and noise were common signs, and 81% of the patients received inappropriate shocks. SJM's RPAs found that the fractures were due to inadequate strain relief and redesigned the IS-1 leg by shortening the crimp bore. Younger age and subpectoral implants appeared to be associated with these fractures. SJM stated the incidence is low (0.040%) and has not seen further fractures of this type in leads with the modified crimp.
  
  
  CONCLUSIONS
  SJM's small diameter leads that were manufactured before 2011 are prone to early outer coil fatigue fractures in the IS-1 leg. The failure mechanism appears to have been mitigated by a design change. RPA is important for improving device safety.
authors.affiliation: Patient Safety and Advocacy Center, Minneapolis Heart Institute Foundation, Minneapolis, Minnesota. Electronic address: rhauser747@aol.com.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Hauser
authors.forename: Linda M
authors.initials: LM
authors.lastname: Kallinen Retel
mesh_terms: D016208:Databases, Factual; D017147:Defibrillators, Implantable; D004867:Equipment Design; D019544:Equipment Failure Analysis; D004869:Equipment Safety; D006801:Humans; D057052:Medical Device Recalls; D011358:Product Surveillance, Postmarketing; D012189:Retrospective Studies; D013610:Tachycardia / Q000628:therapy*; D013997:Time Factors
keywords: Durata lead; FDA; Food and Drug Administration; ICD; Implantable cardioverter-defibrillator; Inappropriate shocks; Lead fracture; Lead size; MAUDE; Manufacturers and User Facility Device Experience; Oversensing; PPR; Product analysis; RPA; SJM; St Jude Medical; Surveillance; implantable cardioverter-defibrillator; product performance report; returned product analysis