Device evaluation conclusion: at the conclusion of the failure analysis investigation the reported event was partially confirmed through analysis.
The fractured guide wire sections were returned without the spring tip section or orbital atherectomy device (oad).
Besides the fracture at the distal end of the wire, the proximal end of the distal core section exhibited a crack in the shaft located at near the proximal end.
The root cause of the crack is unknown but is likely a result of the damaging forces that caused the fracture.
The fractured surface appears ground down.
Scanning electron microscopy (sem) analysis of the distal fracture face exhibited fatigue striations.
The exact root cause of the reported event could not be determined.
The oad ifu warning section informs users of the oad, "when moving the crown advancer knob, make sure there is sufficient distance between the guide wire spring tip and the distal end of the shaft (10 cm minimum).
If the distance between the shaft tip and the guide wire spring tip is insufficient, the shaft tip may damage the guide wire spring tip and result in dislodgement of the guide wire spring tip.
Use contrast injections and fluoroscopy to monitor movement of the shaft tip in relation to the guide wire spring tip.
" sem analysis of the proximal section crack showed the appearance of making contact with a hard substance that narrowed the outside diameter at the crack site, possibly from the spinning driveshaft of the oad.
This can occur as the result of the device spinning over a bend or kink in the guide wire.
However, the exact cause of the crack remains unknown.
The ifu warns "do not operate the device if there is a bend, kink, or tight loop in the guide wire.
A bend, kink, or tight loop in the guide wire may cause damage to and malfunctioning of the device during use.
" (b)(4).
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The viperwire fractured during treatment in the superior femoral artery (sfa), which was severely calcified and 90% stenotic.
An attempt was made to advance an angioplasty balloon into the sfa to continue the procedure, but the balloon could not be advanced through the introducer sheath.
A dissection occurred during the attempt to advance the balloon.
A stent was deployed to treat the dissection.
One fragment of the wire was found to be stuck in the introducer sheath and was removed.
Another fragment was left in vivo.
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