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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.The technical investigation of the returned instrument revealed that the stent is deformed at its distal end.One stent strut is slightly lifted.Microscopic analysis revealed stent imprints on the exposed balloon surface, indicating that the lifted strut was initially crimped on the balloon.Outside of the deformed zone, the crimped diameter complies with the specification.It could be confirmed that only two x-ray markers are present and no foreign material underneath the stent or on the balloon was observed.Dried contrast medium was observed inside of the inflation lumen indicating the application of negative pressure prior to reaching the target lesion.The provided still images of the angiograms were reviewed by an expert.It could be confirmed that the dark spot, marked by the local staff in the screenshots, is most likely an artefact in the artery of the patient, which has no relationship to the complaint instrument at all.The review of the product release documentation of the product detailed above verified that the instrument was manufactured according to specifications and fulfilled all the requirements of in-process and final inspection.As a part of final inspection every stent system undergoes visual inspection to ensure correct embedding and homogeneous crimping of the stent.Further, the stent outer diameter is verified to 100 percent.Based on the conducted investigations of the device being subject to this complaint, no material or manufacturing related root cause could be determined.It should be noted that the ifu states not to apply negative pressure to the stent system at any time prior to placement of the stent across the target lesion.
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