September 28, 2014
View Full PaperRadiographic Predictors of Lead Conductor Fracture
Structured PICO
Do radiographic characteristics on implant chest x-ray predict the risk of lead conductor fracture in patients with Medtronic Fidelis leads?
P
Population
222 patients (111 cases with confirmed Medtronic Fidelis 6949 lead fracture, 111 matched controls with normally functioning leads) from 8 Canadian centers, mean age 61.5±12.8 years, 75% male.
I
Intervention
Specific radiographic characteristics on implant chest x-ray (slack/tortuosity measures, pulse generator and superior vena cava coil location, and angle of lead exit from the pocket)
C
Comparator
Absence of these specific radiographic characteristics
O
Outcome
Confirmed Medtronic Fidelis 6949 lead fracturesafety
Specific radiographic characteristics on implant chest x-ray, such as lead slack and angle of exit, can predict the risk of conductor fracture in high-voltage leads, potentially guiding implant technique.
Abstract
BACKGROUND: Lead fracture is a limiting factor in high voltage lead durability. Fractures noted with the Medtronic Fidelis leads provide an opportunity to examine factors captured on implant chest x-ray that correlate with risk for lead conductor fracture. We evaluated contributory factors in a large population of fractures. METHODS AND RESULTS: We conducted a retrospective case-control study at 8 Canadian centers that routinely capture anterior posterior and lateral chest x-rays within 2 weeks of implant. Cases were patients that experienced confirmed Medtronic Fidelis 6949 lead fracture based on standard definitions, matched one-to-one to controls for date of implant, sex, and age with normally functioning Fidelis leads from the same center. Select chart data and x-rays were collected for all patients. Radiographic measurements by ≥2 individuals per case/control were blinded to patient status. The data were analyzed using a time to failure multivariable Cox proportional hazards model with stratification for each matched pair. X-ray pairs from 111 fracture patients were compared with 111 controls (age 61.5±12.8 years, 75% male, 221 model 6949 leads). Six parameters included in the statistical analysis were significantly associated with risk of fracture, including slack/tortuosity measures, pulse generator and superior vena cava coil location, and angle of lead exit from the pocket. CONCLUSIONS: Pocket, intravascular and intracardiac lead characteristics on x-ray correlate with risk of lead conductor fracture. These observations may be useful to direct implant technique to optimize lead durability. Validation in larger populations and other lead models may inform the application of these results.