MAUDE Adverse Event Report: ON-X LIFE TECHNOLOGIES, INC. ONX MITRAL CONFORM 25/33; HEART-VALVE, MECHANICAL

Model Number ONXMC-25/33

Device Problems Break (1069); Migration or Expulsion of Device (1395)

Patient Problems Insufficiency, Valvular (1926); Device Embedded In Tissue or Plaque (3165)

Event Date 07/30/2017

Event Type  Injury  

Manufacturer Narrative

Explanted device en route for evaluation.Additional information pending.This investigation is currently ongoing.Any additional information will be provided in the follow-up report.

Event Description

According to the surgeon's email on (b)(6) 2017, "i did an emergency redo mitral valve replacement on (b)(6) 2017 [(b)(6) 2017].The initial assesment was of a stuck valve.The patient was in a critical condition on inotropes and ventilated preoperatively.On opening the heart i found one leaflet missing.It was 25/33 onyx valve in 2013.The patient is now stable and in the ward.Ct scan showed leaflet in 2 pieces around the common iliacs.The vascular surgeons will retrieve it next week and i will send you the entire valve and full report.".

Manufacturer Narrative

A sample evaluation was conducted of the returned housing and leaflets (on-x mitral heart valve with conform-x sewing ring, onxmc-25/33, sn (b)(4)).Examination of the sample was thoroughly performed via gross visualization, scanning electron microscopy, as well as evaluation by a materials expert engineer.No scratches or foreign particles were found on the housing.No scratches or foreign particles were found on the housing.-two particles were found on the fracture surface of one of the leaflet sections.They were near the large chip on the flat surface.One particle was either silicon or silicon carbide.One particle was mostly bismuth.The valve on-x carbon material, components and assembly satisfied all applicable manufacturing specifications and quality system requirements at the time of manufacture.Examination of the orifice revealed a haze witness mark on the orifice inside diameter wall at the contact point with the right leaflet major radius tip.The orifice right front and right back pivots were undamaged.The left leaflet was intact, in place within the orifice and unremarkable.Examination of the right leaflet fracture revealed a relatively straight and flat fracture surface along the leaflet midline extending from the leaflet major radius tip to the flat b-datum base.An angular facet with coarse texture and secondary crack branching was present at the leaflet major radius tip.Haze witness marks were present at the inflow aspect surfaces near the leaflet major radius tip angular facet.Examination of the right leaflet pivot tab surfaces, b-datum and radius edge contact regions revealed normal contact burnishing wear witness marks, with no apparent damage.A surface chip was observed on the right leaflet back aspect outflow surface.Visual hazing damage, coarse erosion texture and the leaflet tip fracture origin are consistent with cavitation induced leaflet damage.In order to mitigate the risk and occurrence of cavitation, the on-x valve design includes a feature to prevent squeeze flow and reduce water hammer.With the subject investigation potentially representing the first observed incidence of a cavitation failure in the on-x valve over approximately 86,000 implants, the rate of 1/86000 = 0.00116% is remarkably small.Unlike metals, on-x carbon does not have intrinsic mechanisms for generating damage.Therefore, damage that can propagate in time must be externally introduced to the carbon by an extrinsic mechanism such as cavitation or by iatrogenic causes during surgery or invasive procedures.However, because of the extremely low incidence of cavitation failure in the on-x valve: 1 in 86,000, it is not possible to conclusively eliminate the possibility of iatrogenic damage in cavitation inception.Patient specific factors such as hypertension, tachycardia and activity level, may have also contributed to cavitation.Manufacturing records for the onxmc-25/33, sn (b)(4), were reviewed and it was confirmed that all records were controlled, available for review, and met all specifications per the device master record.All lots passed functional testing and met release specifications.No non-conformances or deviations were noted as part of the manufacturing process.A review of the clinical course was performed.The onxmc-25/33, sn (b)(4), was implanted (b)(6) 2013 and explanted (b)(6) 2017 (3 years 324 days post-implant) after prosthetic valve dysfunction.It was replaced with an unidentified "25mm onyx." patient presented to hospital in extremis - pulmonary edema and hemodynamically unstable.Echocardiography indicated one leaflet of the bileaflet valve could not be visualized, suggesting a stuck leaflet.An emergency re-operation was performed in which the valve was explanted.Examination of the valve upon removal showed that one of the leaflets was missing.It was not located inside the heart and so the replacement "25mm onyx" valve was installed and the patient removed from cardiopulmonary bypass.The missing leaflet was eventually located using ct scan of the body, but it was in two pieces; one piece lodged in the distal abdominal aorta and the other in the left iliac artery.The patient underwent surgery on (b)(6) 2017 for removal of these pieces and was discharged in satisfactory condition with no further medical complications.The valve and fragments were returned to the manufacturer for analysis.Engineering analysis of the valve components concluded that the valve leaflet experienced "rapid brittle bending overload.¿ patient specific factors such as hypertension, tachycardia, and activity level may have also contributed to the failure mode; however, a definitive cause of the reported event cannot be determined.This is a case of prosthesis structural dysfunction, an extremely rare, but acknowledged potential adverse event of mechanical valve replacement surgery.The outcome of explantation is also a recognized possibility following a complication such as this [instructions for use, ifu].Evidence suggests the root cause of the leaflet fracture, with the exception of the angular facet fracture origin, final fracture appearance was characteristic of rapid brittle bending overload.The on-x valve rmf thoroughly identifies the process and product hazards for approved indications.Each individual hazard is mitigated and reduced as low as possible by design and process.Post production residual risk is communicated in the product's labeling and ifu.

Event Description

According to the surgeon's email on (b)(6) 2017, "i did an emergency redo mitral valve replacement on (b)(6) 2017.The initial assesment was of a stuck valve.The patient was in a critical condition on inotropes and ventilated preoperatively.On opening the heart i found one leaflet missing.It was 25/33 onyx valve in 2013.The patient is now stable and in the ward.Ct scan showed leaflet in 2 pieces around the common iliacs.The vascular surgeons will retrieve it next week and i will send you the entire valve and full report.".

• Brand Name: ONX MITRAL CONFORM 25/33
• Type of Device: HEART-VALVE, MECHANICAL
• Manufacturer (Section D): ON-X LIFE TECHNOLOGIES, INC.; 1300 e anderson ln, bldg b; austin TX 78752
• Manufacturer (Section G): ON-X LIFE TECHNOLOGIES, INC.; 1300 e. anderson ln, bldg b; austin TX 78752
• Manufacturer Contact: rochelle maney ; 1655 roberts blvd nw; kennesaw, GA 30144
• MDR Report Key: 6844470
• MDR Text Key: 85109103
• Report Number: 1649833-2017-00064
• Device Sequence Number: 1
• Product Code: LWQ
• Combination Product (y/n): N
• Reporter Country Code: SF
• PMA/PMN Number: P000037
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: distributor,foreign,health pr
• Reporter Occupation: Physician
• Type of Report: Initial,Followup
• Report Date: 11/22/2017

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 09/06/2017
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Physician
• Device Model Number: ONXMC-25/33
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 09/12/2017
• Is the Reporter a Health Professional?: Yes
• Distributor Facility Aware Date: 08/08/2017
• Date Manufacturer Received: 08/08/2017
• Was Device Evaluated by Manufacturer?: Device Not Returned to Manufacturer
• 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): Hospitalization; Life Threatening; Required Intervention
• Patient Age: 21 YR