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Product complaint # (b)(4).A supplemental report will be submitted if new facts arise which materially alter information submitted in a previous mdr report.Section b5: additional information received on 01-mar-2021 indicated that the patient¿s baseline nihss score was 9.The patient¿s nihss score was 16 after the procedure.Complaint conclusion: a report from the field indicated that a 75 years old patient underwent a mechanical thrombectomy procedure using a 5mm x 33mm embotrap ii ( et007533/20g001av) revascularization device at the target site of the m1 segment of the middle cerebral artery (mca) on (b)(6) 2021; and during the procedure the embotrap ii (et2) detached during retrieval and the patient experienced a possible dissection from the carotid to the m1.Consequently, the detached device was left in the brain and within 48 hours the patient expired.During the pass made that encountered the detachment issue, it was reported that there was ¿a lot of plaque¿ in the m1.It was difficult to get the microcatheter through the clot.The embotrap device was pulled, ¿got stuck¿, couldn¿t get out, and was not able to re-sheath in the microcatheter.It was possible that the physician tried to re-capture the embotrap with the sofia (microvention).The physician spent an hour trying to retrieve the embotrap by re-sheathing the microcatheter and aspiration without any success.Eventually, the physician pulled the device ¿really hard¿ and moved/pulled the patient¿s whole head.It is reported that potentially the outer cage of the embotrap was detached.It was not reported if the physician tried to capture the broken part of the device but eventually the remainder of the device, the outer cage was left in place and moved to the m1.At the end of the procedure, it was observed a ¿dissection from the carotid to the m1¿.It is unknown if the physician attempted aspiration first to remove the clot.It is unknown how many passes of any device were made prior to the problematic pass.Additional information received from the sales rep on 02-feb-2021 indicated that the exact date of the patient¿s death is (b)(6) 2021.The brand of aspiration catheter used was the terumo sofia catheter (microvention).It was confirmed that there was no thrombus within the embotrap device during the withdrawal difficulty.There was no identified kinks or damage on the microcatheter.There was difficulty advancing the microcatheter through the thrombus.When the event occurred, it occurred was during the first pass made.The patient had a medical history of chronic myeloid leukemia and heart failure.Additional information received on 01-mar-2021 indicated that the patient¿s baseline nihss score was 9.The patient¿s nihss score was 16 after the procedure.Images were returned for analysis and reviewed by an independent physician, the physician¿s feedback is as follows: ¿this case report is accompanied by two images demonstrating a right m1 mca occlusion.Per the case report, the et2 was deployed but could not be retrieved.The physician tried to resheath it and was unsuccessful.The physician inferred that there was significant plaque that may have been a contributing factor.After an hour, the et2 detached from the delivery system but per the report above it required considerable force, likely beyond the forces used during normal use.The patient expired, the cause of death is unknown from this report.The above report details all reasonable measures were undertaken to remove the et2 in an intact fashion.It is not readily obvious that the m1 occlusion was secondary to atherosclerosis but that is not uncommon.The post procedure ct demonstrates the et2 in the mca and there is no hemorrhage seen on this image.It is unclear without an autopsy as to why the et2 was not retrievable.¿ updated powerpoint presentation received on 09 mar 2021 was reviewed.A follow-up discussion with the physician was held on (b)(6) 2021.The patient¿s symptoms started on friday afternoon ((b)(6) 2021).The patient exhibited slurred speech which was detected by his son (nihss score 9).Brain computed tomography (ct)/computed tomography angiography (cta) demonstrated brachiocephalic artery take-off acute angle from arch and calcifications along the carotid artery.It was stated that ¿all seemed typical, nothing unusual¿.Set-up for the procedure included an 8f neuron max long sheath, 5f vert angiographic catheter, amplatz guidewire in external carotid artery (eca), 6f sofia aspiration catheter, 0.014¿ chikai guidewire (curved, j-tip), and an 0.021¿ headway microcatheter.Exchange technique was utilized.Digital subtraction angiography (dsa) showed right m1 occlusion with no excessive tor tortuosity or unusual problems.The physician verbalized that he normally tries to snake the sofia aspiration catheter up to the clot, but in this case, was unsuccessful.He contemplated using a 5mm x 21mm embotrap versus a 5mm x 33mm embotrap ii, but ultimately decided on the 5mm x 33mm embotrap as ¿it would give more flexibility¿.It was further stated that it was easy to advance and deploy the embotrap and positioning of the device seemed adequate.There was ¿nothing out of the ordinary or suspicious¿.The physician pulled back the device about 1 centimeter (cm) before it ¿got stuck¿.He attempted to re-sheath the device with the concomitant microcatheter but failed; ¿could have re-sheathed 2-3mm, but not more¿.The physician also attempted to advance the sofia aspiration catheter over the embotrap, but this was also unsuccessful.He was able to retrieve the microcatheter and sofia down to the guiding catheter, ¿so freely moved proximally¿, but both became stuck at a certain point.Retrieval was attempted for ¿a long time, could be 45 minutes¿.Eventually, after consulting with the anesthesiologist and neurologist on status of the patient, the decision was made to pull the device ¿strongly¿ to try to get it out.During this process, the physician felt a ¿snap¿ and the device came out without its outer cage.Control dsa revealed a dissection throughout the carotid artery.24-hour post-procedure nihss deteriorated from 9 to 16.The outer cage of the embotrap was clearly visible on repeat ct scan.There was no other obvious hemorrhage or contrast in the brain.The patient ultimately expired within 48 hours of the procedure.The hospital¿s multi-disciplinary team suggested that the most probable reason of the patient death was heart failure, despite the iatrogenic complication.The event was considered probably not related to the leukemia.Additional images were provided and forwarded to an independent physician for review on 12 mar 2021.The results are as follows: ¿the case report is accompanied by a power point presentation containing 20 slides with the case history presentation and multiple angio and ct images.Briefy a 75 yo male presents to a hospital bc of slurred speech his nihss at presentation is 9.Accompanying images on slide 9 and 10 demonstrate a right ca distal m1 occlusion.Mild/moderate tram-track calcifications are noted along the carotid siphon.No significant calcifications are noted in the mca.The patient was referred for thrombectomy.It appears that the original plan was aspiration with a 6 fr.Sofia.However, the sofia could not be advanced beyond the carotid siphon and headway 021 was advanced across the mca occlusion and an embotrap ii was deployed.The physician states that the embotrap ii was stuck and required a lot of force to remove and after consultation with his team he removed the embotrap ii by pulling really hard.Upon inspection of the device the distal cage had fragmented and was implanted in the patients mca (demonstrated on slide 18 and on follow up ct slide 19).The patient expired 48 hrs post procedure from what appears to be heart failure.There are no ct images to suggest a large infarct of the mca distribution cerebral edema etc that contributed to the patient¿s demise.The operating physician noted that there was a dissection of the carotid (slide 4 and 18) and a questionable dissection of the mca (slide 16).Other questions are why did the distal cage fragment and why was the embo trap difficult to remove.The dissection of the cervical ica appears to extend from mid cervical ica (at a mild turn) to the cavernous segment and this is likely due to extensive axial loading and unloading of the guide catheter that occurred with multiple attempts at retrieving the embotrap.Additionally, images on slide 16 suggest a narrowing of the mca origin that appears to resolve on the second image.This is likely vasospasm or compression/pinching of the vessel while trying to remove the embotrap device.Finally, as to why there was difficulty in retrieving the embotrap device.It is unclear as to why this had happened.At times underlying atherosclerotic plaques can make it challenging to retrieve a device.However, there does not appear to be any atherosclerosis in the m1 segment.Also, in cases where there is extensive tortuosity there can be extensive friction or kinking in the system which inhibits the retrieval or manipulation of the stent retriever.At times this can be eliminated by advancing the guide through the tortuosity.Additionally, at time when pulling without an intermediate catheter in place the vector forces are such that the vector force of the pull is straight down towards the feet rather than horizontally into an intermediate or aspiration catheter in the mca m1 segment.There may be an element of this in play here.As we can see when the operator pulls on the wire there is a collapse of the mca origin (slide 16 image 1) which could be because the vector force is towards the feet and not laterally.It is impossible to say if this was the contributing factor in the failure of retrieval.It is extremely rare for the device to fracture at the distal cage.Most fractures usually occur at the proximal segment where the pusher wire and device meet.This likely means an extensive amount of force was used to retrieve the device and after multiple attempts there was fatigue of the distal cage.Ultimately without an autopsy and retrieval of the distal fragment it is impossible to understand why there was difficulty in removing the embotrap ii and why the distal cage fractured.¿ the physical device was returned for analysis.The visual inspection of the stent like assembly of the embotrap device confirmed that there were four (4) discrete locations where material fracture occurred on the device.The fractures of the embotrap device material occurred at the outer cage (on the proximal struts just distal to the proximal gold markers) and at the distal tip (proximal to the spring feature of the inner channel).Based on the follow-up discussion with the physician, the reason for device detachment of the embotrap device is related to the attempted withdrawal of the embotrap device with high force.This force resulted in a material fracture, resulting in the detachment of the outer cage and distal tip on withdrawal of the device.The cause(s) of the resistance to embotrap withdrawal were unknown however it was agreed they could include the concomitant use and interaction with ancillary devices, clinical factors (e.G.Presence of atherosclerosis, vessel characteristics, tortuosity, etc.), embotrap performance or combinations of above.However, none of the potential causes could be concluded during the discussion with the physician.Embotrap ii devices have been assessed for system tensile strength through design verification and process validation activities demonstrating tensile failures at forces.These forces are much higher than forces typically exerted on the device during withdrawal.A review of the manufacturing record evaluation (mre) associated with lot number lot # 20c149av presented no issues during the manufacturing or inspection process that can be related to the reported event.Device analysis conclusion: an analysis of the returned device was completed.It was confirmed that there were four (4) discrete locations where material fracture occurred on the device.The fractures of the embotrap device material occurred at the outer cage (on the proximal struts just distal to the proximal gold markers) and at the distal tip (proximal to the spring feature of the inner channel).High magnification of the fracture locations showed evidence of material deformation proximal to the fracture face.Sem analysis confirmed this deformation to be necking of the material which is consistent with the application of an excessive tensile force causing material failure and fracture.The sem imaging was not consistent with any material defect or incongruity, e.G.Occlusion.The root cause of the device failure was the application of a significant tensile force, above the system tensile strength during retrieval of the device in-vivo.The cause(s) of the resistance to embotrap withdrawal are unknown.During a discussion with the physician, it was agreed that potential cause(s) include the concomitant use and interaction with ancillary devices, clinical factors (e.G.Presence of atherosclerosis, vessel characteristics, tortuosity, etc.), embotrap performance or combinations of above.There is no indication that this complaint was as a result of a defect or malfunction of the embotrap device.Withdrawal difficulty, device detachment, dissection, and death are known potential complications associated with the use of embotrap ii revascularization device in endovascular mechanical thrombectomy procedures.The embotrap instructions for use (ifu) warns the user to never withdraw the device against significant resistance.Assess the cause of resistance using fluoroscopy and if necessary, advance the microcatheter over the device to resheath or partially resheath to aid withdrawal.With the information provided, it is not possible to determine the root cause of the event.However, there are clinical and procedural factors, including vessel characteristics, tortuosity, clot burden/characteristics, device interaction, device selection, and mechanical manipulation of devices within the artery, that may have contributed.Based on the investigations completed, the outer cage detachment was likely due to the high withdrawal force applied to the device during the attempted withdrawal.The cause of the resistance to device withdrawal cannot be identified.The analysis of the returned device does not support that the outer cage material failure is due to a manufacturing or design-related defect.Since the alleged withdrawal difficulty with subsequent device detachment appears to have led to the dissection with fatal outcome.As part of the post market surveillance program, information from this complaint is trended to identify statistical signals for consideration of further correction action.Since there was no evidence to suggest the events were related to a manufacturing or design issue, no corrective actions will be taken at this time.Correction data: b1 is adverse event: checked off.Section b5: updated information was received/reviewed on 09 mar 2021.A follow-up discussion with the physician was held on (b)(6)2021.The patient¿s symptoms started on friday afternoon ((b)(6)2021).The patient exhibited slurred speech which was detected by his son (nihss score 9).Brain computed tomography (ct)/computed tomography angiography (cta) demonstrated brachiocephalic artery take-off acute angle from arch and calcifications along the carotid artery.It was stated that ¿all seemed typical, nothing unusual¿.Set-up for the procedure included an 8f neuron max long sheath, 5f vert angiographic catheter, amplatz guidewire in external carotid artery (eca), 6f sofia aspiration catheter, 0.014¿ chikai guidewire (curved, j-tip), and an 0.021¿ headway microcatheter.Exchange technique was utilized.Digital subtraction angiography (dsa) showed right m1 occlusion with no excessive tor tortuosity or unusual problems.The physician verbalized that he normally tries to snake the sofia aspiration catheter up to the clot, but in this case, was unsuccessful.He contemplated using a 5mm x 21mm embotrap versus a 5mm x 33mm embotrap ii, but ultimately decided on the 5mm x 33mm embotrap as ¿it would give more flexibility¿.It was further stated that it was easy to advance and deploy the embotrap and positioning of the device seemed adequate.There was ¿nothing out of the ordinary or suspicious¿.The physician pulled back the device about 1 centimeter (cm) before it ¿got stuck¿.He attempted to re-sheath the device with the concomitant microcatheter but failed; ¿could have re-sheathed 2-3mm, but not more¿.The physician also attempted to advance the sofia aspiration catheter over the embotrap, but this was also unsuccessful.He was able to retrieve the microcatheter and sofia down to the guiding catheter, ¿so freely moved proximally¿, but both became stuck at a certain point.Retrieval was attempted for ¿a long time, could be 45 minutes¿.Eventually, after consulting with the anesthesiologist and neurologist on status of the patient, the decision was made to pull the device ¿strongly¿ to try to get it out.During this process, the physician felt a ¿snap¿ and the device came out without its outer cage.Control dsa revealed a dissection throughout the carotid artery.24-hour post-procedure nihss deteriorated from 9 to 16.The outer cage of the embotrap was clearly visible on repeat ct scan.There was no other obvious hemorrhage or contrast in the brain.The patient ultimately expired within 48 hours of the procedure.The hospital¿s multi-disciplinary team suggested that the most probable reason of the patient's death was heart failure, despite the iatrogenic complication.The event was considered probably not related to the leukemia.Images were accompanied by the power point presentation including multiple angio and ct images and reviewed by an independent physician.The independent physician's review of the images are as follows: 75 yo male presents to a hospital bc of slurred speech his nihss at presentation is 9.Accompanying images on slide 9 and 10 demonstrate a right ca distal m1 occlusion.Mild/moderate tram-track calcifications are noted along the carotid siphon.No significant calcifications are noted in the mca.The patient was referred for thrombectomy.It appears that the original plan was aspiration with a 6 fr.Sofia.However, the sofia could not be advanced beyond the carotid siphon and headway 021 was advanced across the mca occlusion and an embotrap ii was deployed.The physician states that the embotrap ii was stuck and required a lot of force to remove and after consultation with his team he removed the embotrap ii by pulling really hard.Upon inspection of the device the distal cage had fragmented and was implanted in the patient's mca (demonstrated on slide 18 and on follow up ct slide 19).The patient expired 48 hrs post-procedure from what appears to be heart failure.There are no ct images to suggest a large infarct of the mca distribution cerebral edema etc that contributed to the patient's demise.The operating physician noted that there was a dissection of the carotid (slide 4 and 18) and a questionable dissection of the mca (slide 16).Other questions are why did the distal cage fragment and why was the embo trap difficult to remove.The dissection of the cervical ica appears to extend from mid cervical ica (at a mild turn) to the cavernous segment and this is likely due to extensive axial loading and unloading of the guide catheter that occurred with multiple attempts at retrieving the embotrap.Additionally, images on slide 16 suggest a narrowing of the mca origin that appears to resolve on the second image.This is likely vasospasm or compression/pinching of the vessel while trying to remove the embotrap device.Finally, as to why there was difficulty in retrieving the embotrap device.It is unclear as to why this had happened.At times underlying atherosclerotic plaques can make it challenging to retrieve a device.However, there does not appear to be any atherosclerosis in the m1 segment.Also, in cases where there is extensive tortuosity there can be extensive friction or kinking in the system which inhibits the retrieval or manipulation of the stent retriever.At times this can be eliminated by advancing the guide through the tortuosity.Additionally, at time when pulling without an intermediate catheter in place the vector forces are such that the vector force of the pull is straight down towards the feet rather than horizontally into an intermediate or aspiration catheter in the mca m1 segment.There may be an element of this in play here.As we can see when the operator pulls on the wire there is a collapse of the mca origin (slide 16 image 1) which could be because the vector force is towards the feet and not laterally.It is impossible to say if this was the contributing factor in the failure of retrieval.It is extremely rare for the device to fracture at the distal cage.Most fractures usually occur at the proximal segment where the pusher wire and device meet.This likely means an extensive amount of force was used to retrieve the device and after multiple attempts there was fatigue of the distal cage.Ultimately without an autopsy and retrieval of the distal fragment it is impossible to understand why there was difficulty in removing the embotrap ii and why the distal cage fractured.
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