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Additional information: section c.Investigation - evaluation.On 01jun2020, cook inc became aware of an event that took place on (b)(6) 2020.A patient involved in a clinical trial at stanford university hospital experienced occlusion of the right iliac leg graft.This patient in the zenith iliac branch system clinical study was noted to have thrombosis in the iliac leg graft on the same side as the branch graft on the 2-year ct scan (completed 712 days post-procedure).Intervention involved percutaneous placement of a stent and thrombectomy on (b)(6) 2020.Pre-intervention, the internal iliac artery (iia) was 100% stenosed; post-intervention the iia revealed no stenosis.The intervention was considered successful and no other adverse events or interventions have been reported.A review of the complaint history, device history record (dhr), drawing, instructions for use (ifu), quality control, and specifications of the device was conducted during the investigation.The complaint device was not returned; therefore, no physical examinations could be performed.However, imaging was provided and sent for expert image review.The review noted a region of pre-existing stenosis/narrowing of the distal aorta prior to the procedure.The reviewer also noted on the pre-operative imaging what appears to be a kink along the proximal right external iliac.The kink appears to be located between the end of the spiral-z stent and the beginning of the distal sealing stent.It is possible that the transition between the spiral-z stent and the sealing stent was located at the location of the pre-existing kink in the vessel, leading to the observed kink in the graft.This kink was treated by the deployment of the intravascular stent at the level of the kink as shown on post-operative imaging from the intervention.Cook has concluded that this device was manufactured to specification.Additionally, a document-based investigation evaluation was performed.A review of the device master record (dmr) concluded that sufficient inspection activities are in place to identify this failure mode prior to distribution.A review of the design history file (dhf) showed that this device is both safe and effective for its intended use.A review of the dhrs for the reported device lot (8481971) and the related subassembly lots revealed no recorded non-conformances.A database search found no other events associated with the reported device lot.It should be noted that zsle devices are distributed via one-device lots.Given this information, cook has concluded that there is no evidence suggesting nonconforming product exists either in house or in field.Cook also reviewed product labeling.The product instructions of use (ifu), [t_zaaasz_rev3] ¿zenith® spiral-z aaa iliac leg with the z-trak¿ introduction system¿, provides the following information to the user related to the reported failure mode: ¿4 warnings and precautions- 4.1 general: patients experiencing reduced blood flow through the graft limb and/or leaks may be required to undergo secondary interventions or surgical procedures.4.2 patient selection, treatment and follow-up: adequate iliac or femoral access is required to introduce the device into the vasculature.Access vessel diameter (measured inner wall to inner wall) and morphology (minimal tortuosity, occlusive disease and/or calcification) should be compatible with vascular access techniques and delivery systems of a 14 french to 16 french vascular introducer sheath.Vessels that are significantly calcified, occlusive, tortuous or thrombus-lined may preclude placement of the endovascular graft and/or may increase the risk of embolization.A vascular conduit technique may be necessary to achieve success in some patients.Pre-existing regions of stenosis/narrowing (less than approximately 20 mm id in the aorta or 7 to 8 mm id in the iliacs) have been shown to increase the risk of a thromboembolic event (e.G., graft limb occlusion).The potential for this increased risk in these patients may preclude placement of an endovascular graft.Dilatation of these regions with a noncompliant balloon and/or stent placement may be necessary to help assure maintained graft patency and to reduce the risk of a thromboembolic event.Additionally, the completion angiogram (with stiff wire guides removed) should be reviewed carefully to determine if further treatment in these regions is necessary (e.G., adjunctive ballooning or stenting).Failure to remove the stiff wire guide prior to the angiogram could mask any limb kinking or narrowing that might occur when the wire guide is removed.Follow-up imaging should be carefully reviewed for narrowing within the graft leg.Patients with a graft leg lumen of less than approximately 5 mm id may be at increased risk of a thromboembolic event (e.G., graft limb occlusion).Reintervention (e.G., noncompliant ballooning or stenting in these regions) should be considered to help assure maintained graft patency and to reduce the risk of a thromboembolic event.Patients with poor outflow or a hypercoagulable state (e.G., cancer) may be at an increased risk of a thromboembolic event.The zenith spiral-z aaa iliac leg has not been explicitly evaluated clinically; however its performance is represented by the zenith aaa endovascular graft iliac leg (a previous version of the device), which has not been evaluated in the following patient populations: key anatomical elements that fall outside the sizing requirements specified in the appropriate main body or renu instructions for use.4.4 device selection: strict adherence to the zenith spiral-z aaa iliac leg ifu sizing guide is strongly recommended when selecting the appropriate device size.Appropriate device oversizing has been incorporated into the ifu sizing guide.Sizing outside of this range can result in endoleak, fracture, migration, device infolding or compression.4.5 implant procedure: systemic anticoagulation should be used during the implant procedure based on hospital- and physician-preferred protocol.If heparin is contraindicated, an alternative anticoagulant should be considered.Use caution during manipulation of catheters, wires and sheaths within an aneurysm.Significant disturbances may dislodge fragments of thrombus, which can cause distal embolization, or may rupture the aneurysm.Excessive overlap 10 mm above the main body bifurcation may increase the risk of limb thrombosis.5 adverse events- 5.2 potential adverse events: adverse events that may occur and/or require intervention include, but are not limited to: arterial or venous thrombosis and/or pseudoaneurysm.Claudication (e.G., buttock, lower limb).Endoprosthesis: occlusion.Graft or native vessel occlusion.7 patient selection and treatment- 7.1 individualization of treatment: the risks and benefits should be carefully considered for each patient before use of the zenith spiral-z aaa iliac leg.Additional considerations for patient selection include, but are not limited to: patient¿s age and life expectancy co-morbidities (e.G., cardiac, pulmonary or renal insufficiency prior to surgery, morbid obesity).The final treatment decision is at the discretion of the physician and patient.8 patient counseling information- physicians must advise all patients that it is important to seek prompt medical attention if they experience signs of limb occlusion, aneurysm enlargement or rupture.Signs of graft limb occlusion include pain in the hip(s) or leg(s) during walking or at rest or discoloration or coolness of the leg.Device-related risks include occlusion, endoleak, aneurysm enlargement, fracture, potential for reintervention and open surgical conversion, rupture and death.11 directions for use- anatomical requirements: iliofemoral access size and morphology (minimal thrombus, calcium and/or tortuosity) should be compatible with vascular access techniques and accessories.Arterial conduit techniques may be required.11.1 zenith spiral-z aaa iliac leg system.11.1.4 contralateral iliac leg placement and deployment.3.Introduce the contralateral iliac leg delivery system into the artery.Advance slowly until at least one stent of the iliac leg graft overlaps within the main body and not past the radiopaque marker band positioned 30 mm from the proximal end of the iliac leg graft inside the contralateral limb of the main body.If there is any tendency for the main body graft to move during this maneuver, hold it in position by stabilizing the gray positioner on the ipsilateral side.4.Confirm position of distal end of the iliac leg graft.Reposition the iliac leg graft if necessary to ensure internal iliac patency, a minimum overlap of one stent, and a maximum overlap of 30 mm within the main body endovascular graft.11.1.5 ipsilateral iliac leg placement and deployment.Note: if using this device in conjunction with a zenith alpha abdominal endovascular graft or zenith low profile endovascular graft, proceed to section 11.1.16, ipsilateral iliac leg placement and deployment in conjunction with zenith alpha abdominal endovascular graft or zenith low profile endovascular graft.For all other systems, continue with steps 1-7 below.2.Advance slowly until the ipsilateral iliac leg graft overlaps a minimum of one stent inside the ipsilateral limb of the main body.3.Confirm position of distal end of the iliac leg graft.Reposition the iliac leg graft if necessary to ensure internal iliac patency.11.1.6 ipsilateral iliac leg placement and deployment in conjunction with zenith alpha abdominal endovascular graft or zenith low profile endovascular graft 4.Introduce the ipsilateral iliac leg delivery system, and continue advancing slowly until the proximal edge of the ipsilateral leg graft aligns with the proximal edge of the previously-placed contralateral leg graft.5.Confirm position of the distal end of the iliac leg graft.Reposition the iliac leg graft if necessary to ensure internal iliac patency.¿ based on the information provided, review of the provided imaging, and the results of our investigation, a potential root cause for this event has been traced to the patient's condition rather than the device.Potential causes of the occlusion could be related to pre-existing stenosis/narrowing of the distal aorta or a kink in the graft stemming from pre-existing vessel tortuosity.Additionally, it was reported that the patient was on a regimen of aspirin and was prescribed plavix for one year post-implantation.The patient's medical history included hypertension and past prostate cancer.The reported occlusion may have resulted from one or a combination of those factors which then may have led to an increase in thrombus formation and occlusion.Additionally, thrombus formation is a known inherent risk of using this device.The appropriate personnel have been notified.Cook will continue to monitor for similar complaints.Per the quality engineering risk assessment no further action is required.This report is required by the fda under 21 cfr part 803 and is based on unconfirmed information submitted by others.Neither the submission of this report nor any statement contained herein is intended to be an admission that any cook device is defective or malfunctioned, that a death or serious injury occurred, nor that any cook device caused, contributed to, or is likely to cause or contribute to a death or serious injury if a malfunction occurred.
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