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The returned device was subjected to a detailed technical analysis and the corresponding product release documentation was reviewed to establish whether a deviation from the manufacturing process could be the cause for this event.In addition, the angiographic material provided was reviewed.The technical investigation revealed that the stent is deformed at its distal end, i.E.Few struts are bent.Microscopic inspection showed stent imprints on the exposed balloon surface, indicating that the deformed struts were initially crimped on the balloon.The balloon is well folded and shows no signs of inflation, but contrast medium residue was observed in the inflation lumen which indicates application of negative pressure.The angiographic material shows the implantation a stent in the target vessel.Thereafter, an unsuccessful attempt of crossing the proximal portion of the previously implanted stent with the complaint instrument is visible.After withdrawal of the complaint instrument, a shorter stent is successfully implanted.It remains unclear if the complaint stent was deformed prior to or during the crossing attempt.The angiographic material does therefore not provide any further relevant information with regards to the root cause of the complaint.Review of the product release documentation confirmed that the device was manufactured according to specifications and fulfilled all the requirements of in-process and final inspection.During final inspection, every stent system undergoes visual inspection to ensure correct stent embedding and homogeneous crimping of the stent.Further, the stent outer diameter is verified to 100 percent and the stent retention force of a defined number of samples is tested from every lot.Based on the conducted investigations of the device being subject to this complaint, no material or manufacturing related root cause could be determined.
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