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(b)(4).Pma/510(k) # p100022/s001.As 3 stents are suspected to be involved in this event a separate report has been submitted for each suspect device.Reference also reports # 3001845648-2017-00603 and 3001845648-2017-00604.This investigation will capture the restenosis of ziv6-35-125-7.0-120-ptx stent of lot number c779614.The ziv6-35-125-7.0-120-ptx stent of lot number c779614 was implanted in the patient and is therefore unavailable for evaluation.With the information provided a document based investigation was carried out.The patient had the following pre-existing conditions: coronary artery disease, hypertension, diabetes, hypercholesterolemia, renal failure, ever smoked & pad (peripheral artery disease).Images were provided to support the complaint investigation.They were reviewed through cook research inc.(cri) and the following comments were provided by the independent reviewer: findings: angiography from a secondary intervention performed 4.5 years post implantation is provided along with the complaint report.The left distal common iliac artery (cia) and the external iliac artery (eia) had been stented.Imaging of this inflow was either not performed or not provided.The left foot had been previously amputated at the calcaneus, proximal to the plantar arch.Three zilver ptx stents extended from the mid left common femoral artery (cfa) into the distal left superficial femoral artery (sfa) terminating proximal to the adductor canal.Total stented length was 291mm.The proximal and mid stents overlapped 33mm and the mid and distal stents 11mm.The stents were expanded to their full design diameter of 7mm and without focal compression or fracture.The proximal stent was occluded from the sfa origin to the overlap with the mid stent.The mid and distal stents were patent but diffusely moderate and focally severely narrowed from neointimal hyperplasia.Runoff was severely limited by diffuse, severely calcified plaque causing diffuse 50% stenosis except at the sfa/ popliteal artery (pa) junction where the stenosis was significantly worse.This stenosis was not measurable secondary to patient motion during the angiogram.The anterior tibial and peroneal arteries occluded just distal their origins.The tibial/ peroneal trunk was severely, diffusely narrowed from near occlusive plaque.The posterior tibial artery (pta) was severely narrowed from near occlusive plaque from its origin and through a mid-calf stent until the distal calf where it completely occluded.Sixteen minutes elapsed between wire passage through the proximal stent occlusion and angioplasty of the sfa with a very low profile balloon, likely a 2mm balloon.The very low profile balloon likely indicated difficulty passing a larger balloon and therefore explains the 16 minute gap.Alternatively, but less likely, the time was used to perform thrombolysis and or debulking, however no imaging demonstrating this was provided.Other than possibly missing the imaging of the left iliac artery inflow, the time gaps suggest that other omissions were unlikely.The stents were angioplastied with a larger, likely 5mm, balloon.The sfa/pa junction stenosis was angioplastied, resulting in less than 30% residual stenosis relative to the diffuse moderate adjacent artery.The severely narrowed tibial peroneal trunk, the proximal patent pta including the stent, the pta occlusion and the distal pta were angioplastied into the foot however the pta occluded in the proximal foot with filling of abnormal local collaterals only.The plantar arteries remained occluded.Repeat angiography of the stents demonstrated significant recoil of the proximal stent neointimal hyperplasia that improved after additional angioplasty.Upon completion, moderate 50%, stenosis from neointimal hyperplasia remained in the stents but one vessel runoff was reestablished into the proximal left foot.Impression: proximal stent occlusion and mid and distal stent significant in-stent stenosis is confirmed.Because thrombolytic or thrombectomy procedures were likely not performed and no embolization occurred, the amount of thrombus present, if any, was negligible.The proximal stent occluded from severe neointimal hyperplasia.Moderate and severe neointimal hyperplasia is confirmed in the mid and distal stents.Severe outflow limitation at the sfa/ pa junction and in the calf increased the probability of significant neointimal hyperplasia formation.The presence of the pta stent and the prior amputation indicate that this was chronic.Significant findings relative to the patient's anatomy were not observed.Significant findings relative to the disease state were not observed.Severe, distal atherosclerotic disease limited outflow.Small vessel occlusion at the level of the calf and foot made the reported subsequent amputation a foregone conclusion regardless of the in-stent stenosis.Significant findings relative to the use of the device were not observed.Significant findings relative to the design or performance of the device were observed.The stents developed severe neointimal hyperplasia with occlusion of the proximal stent.Cause of adverse events was not observed.Based on the imaging review received the customer complaint of occlusion can be confirmed.However it was as a result of restenosis, not thrombosis as initially reported.The proximal stent occluded from severe neointimal hyperplasia.Moderate and severe neointimal hyperplasia is confirmed in the mid and distal stents.The independent reviewer was contacted to determine if the amputation that took place was related to the zilver device implanted.The follow was received: ¿two amputations were performed.There was a remote foot amputation.The amputation mentioned in the complaint report occurred after the secondary intervention.This likely was a below knee amputation.The stent in the posterior tibial artery pre-dated the secondary intervention.Its temporal relationship to the first amputation is unknown.The first amputation was not related to a zilver ptx.The second amputation was related to the zilver stents however the poor runoff was the dominant cause of the additional amputation.¿ it may be noted that clinical input from the medical advisor was also received, the following was stated: ¿¿i cannot rule out the possibility that our stent contribute to the amputation, however, small vessel occlusion (neointimal hyperplasia formation) could be from the pta stent as well which also could lead to amputation.Obviously, patient¿s condition of distal atherosclerotic disease didn¿t do any favour in this case¿ i also wonder this patient¿s pre-existing condition such as if the patient had diabetes, if the diabetes wasn¿t under control, this patient will end up with amputation eventually no matter what medical intervention was performed (medication, stent, etc.) the potential cause of restenosis is not directly related to the design of the device and therefore cannot be reduced further by design.Arterial injury is an unavoidable outcome from the angioplasty/stenting procedure.Angioplasty alone can cause arterial injury leading to restenosis.Therefore restenosis caused by the angioplasty/stenting procedure poses no greater risk than angioplasty alone.Clinical study results indicate that the risk of restenosis when the zilver ptx stent is used is significantly lower than when angioplasty alone is performed, or when stenting with a bare zilver stent is performed.As determined by risk/benefit analysis the clinical benefits of the zilver ptx drug-eluting stent system outweigh the risks to the patient.Restenosis is a common adverse event of endovascular procedures and can be caused by injury to the vessel (e.G.During percutaneous transluminal angioplasty (pta) and/or stenting).Vessel injury provokes an inflammatory response that leads to (or amplifies) the restenosis process.It may be noted that surface of the zilver ptx stent is coated with the drug (paclitaxel) to help prevent subsequent restenosis of the artery.It can be therefore stated that it is very unlikely that the reported restenosis could have occurred due to zilver ptx malfunction; however a definitive root cause of this event cannot be determined at this time.It may be noted that the packaging insert lists restenosis of the stented artery as a known potential adverse event associated with placement of this device.In addition, rest pain is also listed as a potential adverse event associated with placement of this device in the packaging insert.Prior to distribution all zilver ptx devices are subject to visual inspection and functional checks to ensure device integrity.A review of the relevant manufacturing records revealed no discrepancies that could have contributed to this complaint.Upon review of complaints, this failure mode has occurred previously with the lot number c779614.However based on the information available to date, there is no evidence to suggest that there are any manufacturing issues associated with the lot number c779614.Pta and amputation above-the-knee were performed.The patient had a favourable outcome.Complaints of this nature will continue to be monitored for any potential emerging trends.
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