MAUDE Adverse Event Report: COOK IRELAND LTD ZILVER PTX 35 DRUG-ELUTING STENT; NIU STENT, SUPERFICIAL FEMORAL ARTERY, DRUG-ELUTING

Model Number G24890

Device Problem Kinked (1339)

Patient Problem Occlusion (1984)

Event Type  Injury  

Manufacturer Narrative

(b)(4).It may be noted that there are two reports open for this complaint: this complaint report investigates the issue 'stent kinked post implantation.'reference also report# 3001845648-2018-00021 which investigates the 'restenosis' issue.The device 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: this (b)(6) female presented at the time of enrollment with a history of hypertension and smoking (current).The lesion morphology revealed a tasc i type c lesion and a tasc ii type b lesion with thrombus and mild calcification.There was no previous intervention in the study lesion.There was no inflow tract stenosis greater than 50% and there were three patent runoff vessels.Baseline angiographic lesion measurements revealed a proximal reference vessel diameter (rvd) of 5 mm and distal rvd of 5 mm.There was 100% diameter stenosis.The lesion length was 55.0 mm.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: pre-implantation and implantation angiography are provided.Post-implantation six, 12, and 24 month ultrasounds are provided.Six and 24 month plain films are provided.A 24 month abi is provided.Imaging of the complaint reported at three years was provided.The stent was implanted across a distal right superficial femoral artery into an above the knee popliteal artery occlusion.The stenosis was completely relieved.The stent extended 1 cm inferior to the femoral epicondyles.In the proximal, mid, and distal sfa, angiographic 50% stenoses superimposed on diffuse atherosclerotic irregularity were left untreated.The proximal and mid stenoses were likely greater than 50% because enface plaque was evident at these stenoses.On all three follow up ultrasounds, these stenoses demonstrated peak to baseline systolic velocity ratios greater than 2:1, consistent with 50-99% stenosis.Between six months and one year, new flow reversal in the right anterior tibial artery on ultrasound indicated proximal anterior tibial artery occlusion.Since the abis depended on the status of the posterior tibial artery, this did not degrade the right abi.Stability of the right abi through two years indicated stable atherosclerotic disease from the right iliac arteries through the posterior tibial artery, including the diseased sfa and the stent.The bent knee x-ray performed at 24 months demonstrated transient stent element distortion at the femoral epicondyles, consistent with kinking and/ or twisting.On ultrasound, in-stent and adjacent artery stenosis was not observed.Angiography at approximately two years was reported as unscheduled.Study stent angioplasty followed diagnostic angiography and overnight thrombolysis.The unscheduled presentation and prompt treatment indicate that although underlying lesions may have been present, an acute thrombosis was the primary event.The stent and a short segment of sfa proximal to the stent were occluded.Overnight thrombolysis and subsequent drug coated balloon (dcb) angioplasty indicated that the occlusion was all clot except for a focal, moderate to severe, 50-75%, distal in-stent stenosis from neointimal hyperplasia.This stenosis developed exactly where knee flexion kinked the stent.A less than 50% distal sfa stenosis at implantation had progressed to greater than 75%.One of the previously imaged mid sfa stenosis that initially appeared angiographically moderate but was more severe on ultrasound also progressed to 60%.Because the plaque was still primarily enface, the stenosis was likely more severe than it appeared.The proximal sfa stenosis was stable.Anterior tibial artery occlusion as suspected by ultrasound was confirmed.The sfa stenoses and distal stent neointimal hyperplasia were relieved with dcb angioplasty following thrombolysis.Follow up ultrasound one week after the secondary intervention demonstrated continued resolution of the sfa and in-stent stenoses.Impression: the primarily thrombotic stent occlusion was secondary to knee flexion precipitated thrombosis of neointimal hyperplasia in the distal stent and progressive inflow limitation from proximal sfa stenoses.These processes were aggravated by continued tobacco abuse.The neointimal hyperplasia occurred where knee flexion transiently kinked the stent.The complaint is confirmed as stent implantation inferior to the femoral epicondyles subjected the stent to kinking with knee flexion.This complaint was determined to be user error.As per the imaging review, the stent extended 1 cm inferior to the femoral epicondyles.The instruction for use that accompany this device states that the device be used for ¿above the knee femoropopliteal arteries¿.The following is also listed as a precaution ¿¿to avoid involvement of the below-the-knee popliteal artery, the most distal stent end should be place above the plane of the femoral epicondyles.¿ as per the imaging review, the most probable root cause is this complaint is the user error i.E.Stent implantation inferior to the femoral epicondyles subjected the stent to kinking with knee flexion.The following query was been sent to cri : ¿¿can you also clarify the following: the bent knee x-ray performed at 24 months demonstrated transient stent element distortion at the femoral epicondyles, consistent with kinking and/ or twisting.This is the only section where twisting of the stent was referenced.Was the stent kinked or twisted or is it not possible to say exactly which occurred?¿ the following was received: "the occlusion was primarily thrombosis with some restenosis where the stent kinked and or twisted with knee flexion.There was not nearly enough neointimal hyperplasia to occlude the stent.The stent need some transient event to cause it to clot.Knee flexion is the usual cause of this particularly with lower sfa popliteal stent such as this.However because it went for a long time without a problem knee flexion alone could have not been the sole cause.Knee flexion can cause neointimal hyperplasia.The neointimal hyperplasia was exactly were sent deformed on x-ray.Although it cannot be determined kinking and twisting were likely both present.After three years enough neointimal hyperplasia had built up inside the stent that when the knee was flexed, the lumen was just not narrowed but completely occluded.This is the most plausible explanation for primary thrombosis of a stent three years after implantation with just one focus of moderate to severe restenosis that also matched where the stent had previously been shown to twist and kink.The anterior tibial artery occlusion predated the occlusion and was consequently unrelated to the stent occlusion.It was a sign of progressive atherosclerotic disease and outflow limitation that could have a deleterious effect on stent patency in that the patient went from having two vessel to one vessel runoff." 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 not occurred previously with the lot number c950186.Based on the information available to date, there is no evidence to suggest that there are any manufacturing issues associated with the lot number c950186.Thrombolysis & angioplasty were performed as a result of this occurrence.The patient remains in the study.Complaints of this nature will continue to be monitored for any potential emerging trends.

Event Description

Stent was subject to kinking as a result of knee flexing.The (b)(6) ¿ occlusion/restenosis definitely related to study product at the index procedure on (b)(6) 2014, the patient received one 6 mm x 80 mm zilver ptx study stent in the right popliteal artery.On (b)(6) 2014, the patient underwent pre-dilatation of study lesion with one inflation of a 5.0 x 80 mm balloon at 6 atm for 45 seconds and a second inflation at 5 atm for 60 seconds.One 6.0 mm x 80 mm study stent (lot # c950186) was placed in the popliteal artery via contralateral access.The implanting physician noted that device deployment was easy.No non-study stents were used to treat the study lesion.Post-stent dilatation was performed with two inflations of a 5.0 mm x 80 mm balloon at 4 atm for 15 seconds and 10 atm for 10 seconds.At the conclusion of the case, thrombus was present and was treated.There was no dissection noted by the site, and the entire length of the study stent was apposed to the vessel wall.There was 10% residual stenosis remaining in the study lesion.The proximal and distal rvds were 5.0 mm.The post-procedural abi was 0.93 for the study leg.On the same day, the patient was discharged from the hospital taking aspirin and plavix.On (b)(6) 2017 (1433 days post-procedure), the patient experienced an occlusion/restenosis of the study lesion (and proximal to the study lesion) requiring intervention.The patient had continued to take aspirin.Thrombolysis was performed on (b)(6) 2017 and angioplasty was done on (b)(6) 2017.The physician determined that the occlusion/restenosis of the study lesion was definitely related to the study product and not related to the study procedure.To the question, ¿did the device malfunction or deteriorate in characteristics or performance?¿, the investigator marked no.The image review ranging from (b)(6) 2013 - (b)(6) 2016 was received.Included in the impression section of the imaging review it stated that the stent was subject to kinking as a result of knee flexing.Reference also report# 3001845648-2018-00021 which investigates the 'restenosis' issue.

• Brand Name: ZILVER PTX 35 DRUG-ELUTING STENT
• Type of Device: NIU STENT, SUPERFICIAL FEMORAL ARTERY, DRUG-ELUTING
• Manufacturer (Section D): COOK IRELAND LTD; o halloran road; limerick
• Manufacturer Contact: michael galvin ; o halloran road; national technology park; limerick ; 061334440
• MDR Report Key: 7234101
• MDR Text Key: 98787806
• Report Number: 3001845648-2018-00042
• Device Sequence Number: 1
• Product Code: NIU
• UDI-Device Identifier: 10827002248905
• UDI-Public: (01)10827002248905(17)140304(10)C950186
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: P100022
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative,health
• Reporter Occupation: Physician
• Type of Report: Initial
• Report Date: 01/04/2018

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 02/01/2018
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Health Professional
• Device Model Number: G24890
• Device Catalogue Number: ZIV6-35-125-6-80-PTX
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Was the Report Sent to FDA?: No
• Distributor Facility Aware Date: 01/10/2018
• Event Location: Hospital
• Date Manufacturer Received: 01/04/2018
• Date Device Manufactured: 11/25/2013
• Is the Device Single Use?: Yes
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Initial
• Patient Sequence Number: 1
• Patient Outcome(s): Required Intervention
• Patient Age: 70 YR