|
According to initial reports, "the patient was known with a history of rheumatic heart disease, and had a previous mitral valve replacement and on this admission presented with a stuck mitral prosthesis.He was taken to theatre for a re-do mitral valve replacement on (b)(6) 2019 which was uneventful.A stuck size 27/ 29 mitral valve was removed [reported previously ¿ (b)(4), mrn - 1649833-2019-00067], it was noted to have fresh clot and pannus on the valve.A new valve was inserted a similar size (27/29 mm ony-x valve) , on echo the valve seated well and the leaflets were moving normal.He was separated from the cardiopulmonary bypass uneventful with adrenaline about o.1mcg/kg.He was extubated on day 1 in icu, was conscious and had normal blood results and vitals.About 36 hours after he had a generalized clonic tonic seizure which self-terminated about in approximately 2 min and following that the patient was awake with normal vitals and had a ctb which showed no abnormalities.About 6 hours again the patient had another seizure with loss of cardiac output, resuscitation was unsuccessful." this event is relegated to onxm-27/29, (b)(4).
|
|
The manufacturing records for the onxm-27/29 sn (b)(6) 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.During the investigation no non-conformances or deviations were noted.A review of the available information was performed.Male patient (dob (b)(6)1988) implanted with onxm-27129 sn (b)(6) [report no.1649833-2019-00067] on (b)(6) 2015 indicated rheumatic valvular heart disease which was explanted on (b)(6) 2019 for stuck mitral prosthesis due to pannus and fresh thrombus (at the hinge) with subsequent replacement via additional onxm-27/29.Medical notes were obtained.Surgery completed and patient transferred to icu in stable condition.According to the notes, ¿he was extubated on day 1 in icu, was conscious and had normal blood results and vitals.About 36 hours after he had a generalized clonic tonic seizure which self terminated about in approximately 2 min and following that the patient was awake with normal vitals and had a ctb (computerized tomography brain) which showed no abnormities.About 6 hours again the patient had another seizure with loss of cardiac output, resuscitation was unsuccessful.The cause or death is suspected to be an embolic event to either brain or coronary artery or dysrhythmias or a possible malfunction.Medical records indicate patient history of retroviral disease (rvd) on fixed dose combination drug (fdc) ¿ it is not stated whether the rvd was hiv or htlv.However, rheumatic heart disease is prevalent among hiv populations.The patient in this case first received a mitral valve replacement due to rheumatic heart disease.A definitive root cause for the pannus cannot be determined.However, the presence of intense fibrosis and calcification in rheumatic valves may promote impingement of pannus tissue on the prosthesis and cause obstruction of the mitral inflow tract.[kalcik] that is, rheumatic heart valve cardiac conditions may predispose a prosthesis to pannus formation.A ¿fresh thrombosis¿ was also noted on the hinge region of the valve.Regarding historical patient anticoagulation management, the medical records indicate ¿he has been following up with cardiology on an annual basis but defaulted in 2016.He reportedly remained well in the interim and followed up at turton clinic in port shepstone for monthly inr checks.He states that inr has frequently been less than 2 this year and his warfarin doses were subsequently increased.He was never admitted to his base hospital for adjustment in anticoagulation.¿anticoagulation compliance is questionable.The patient stopped seeing his cardiologist in 2016 but followed up for monthly inr checks.It states that the inr ¿has frequently been less than 2.¿ the ifu states that ¿patient with an on-x valve in the mitral valve position or in multiple valve positions should be maintained at an inr of 2.5 ¿ 3.5 continuously after valve replacement surgery.Additionally, the patient stated that his warfarin dose was increased yet he ¿was never admitted to his base hospital for adjustment in anticoagulation.¿ the patient is clearly sub-therapeutic and likely non-compliant overall which may have predisposed thrombus formation.Additionally, rvd may have contributed to the thrombus formation as well.¿persistent abnormalities in coagulation appear to contribute to excess risk for a broad spectrum of non-aids defining complications, including, but not limited to, venous and arterial thrombolic disease.Mechanisms specific to hiv disease, antiretroviral therapy, and lifestyle or behavioral factors contribute to a pro-coagulant state, in part, through increased tissue factor activity coupled with a paradoxical decline in the anti-coagulant response.Alterations in coagulation biology in the context of hiv disease appear to be largely a consequence of persistent systemic immune activation, micro- macro-vascular disease, and potentially, impaired hepatic synthesis of coagulation factors.[baker].¿ the surgeon indicated that "the cause of death is suspected to be an embolic event to either brain or coronary artery or dysrhythmias or a possible valve malfunction.¿ there is obvious uncertainty by the surgeon regarding cause of death due to the multiple and varied etiologies suggested.Although a definitive cause of death cannot be determined based on the available, it is likely due to decreased cardiac output with subsequent heart failure.The medical records explicitly sate ¿seizure with loss of cardiac output¿ which implies seizure induced cardiac abnormalities.In addition to seizure-related [heart] rate abnormalities, seizures also may cause rhythm and conduction abnormalities [neil].This would align with the surgeon¿s suggestion of dysrhythmia as a cause of death.Determining a cause for the seizure activity is complicate and we are unable to make a definitive determination.However, seizures occurring after cardiac surgery are thought to be the result of focal or global cerebral ischemia from hypoperfusion, particulate or air emboli, metabolic derangements [1], or drug reactions including withdrawal (goldstone) the first seizure occurred approximately 36 hours postop which was preceded by "normal blood results and vitals.¿following this seizure the patient was awake with normal vitals and a ctb indicated no abnormities which would seem to rule out cerebral ischemia via embolism as a cause of the seizure activity and contradicts the suggestion by the surgeon as a cause of death.The next suggestion references a coronary artery embolism as a cause of death.It is possible that the mitral prosthetic thrombus embolized to the coronaries.Coronary embolism most commonly results in elevated heart rates which can result in decreased cardiac output.However, there is no symptomatic evidence of this as the patient had normal vitals and tachycardia would have been evident.Furthermore, coronary embolisms are not listed as a cause of post cardiac surgery seizure activity.The last suggested cause of death by the surgeon states ¿possible valve malfunction.¿ this is unlikely as medical records indicate that the new valve was performing as intended."on echo the valve seated well and the leaflets were moving normal.¿ despite the cause, the final seizure 6 hours later was accompanied by decreased cardiac output that was resistant to resuscitation and unfortunately, the patient died.The initial valve was returned for sample evaluation.Prior to decontamination, visual examination of valve showed evidence of pannus.There was tissue growth on both sides of the valve.After decontamination, there were no obvious signs of damage to the valve or leaflets.The leaflets were able to move freely once the tissue had been removed no evidence of defect with the valve or leaflets.Pannus formation for the on-x mitral valve is rare as the valve protrudes, in part into the annulus.But over time, there can be tissue overgrowth, which, as in this case, can constrict the inflow area leading to stenosis.The instructions for use lists prosthesis pannus and thrombosis as potential adverse events.Such complications may result in reoperation and/or explantation or death [ifu].Definitive root cause for the pannus cannot be determined however it is plausibly related to rheumatic heart conditions.Valve thrombosis is likely associated with patient anticoagulation noncompliance and subtherapeutic inr levels.A definitive cause of death cannot be determined but it is possibly related to seizure induced cardiac abnormalities resulting in decreased cardiac output and subsequent heart failure.No further action is required.This report is being submitted as required by federal regulations and does not constitute an admission that the device caused or contributed to the reported event.Furthermore, this report reflects the event as alleged by the complainant and does not imply that the information reported to cryolife is accurate or has been confirmed by cryolife.
|
