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Heparin

Media statement - Heparin

23 May 2008

An expert advisory committee has endorsed the Ministry’s approach to managing the risk posed from contaminated heparin used in a coating in medical devices.

The expert group was convened yesterday to provide expert advice to the Ministry's medicines and medical devices regulatory arm Medsafe. The committee endorsed the actions taken to date by Medsafe.

Medsafe’s enquiries have identified six different types of medical devices available within New Zealand that result in contact with patients. Manufacturer testing of these devices has identified only one product that is coated with contaminated heparin.

This device is called the Trillium Affinity NT Hollow Fibre Oxygenator and is used in heart-lung bypass surgery.

Medtronic, the manufacturer of the affected product, last week advised clinicians to quarantine the product and where stocks permit to use uncontaminated product. The company estimates it will be 2-3 months before replacement stock of uncontaminated product is available.

In the interim Medsafe and the Advisory committee’s consensus advice is that where no alternatives products are available, affected products should still be used. The benefits of using the Trillium Affinity Oxygenator continues to outweigh the very small risk of severe allergic-type reactions that have been reported in association with injectable forms of contaminated heparin.

Medsafe and the Advisory Committee reviewed a risk assessment performed by Medtronic.

The assessment reports that the device contains very small amounts of heparin within its coating. The risk analysis also reports that laboratory testing of the device when it was in-use found that no contaminant was released.

Furthermore, Medsafe agrees with this risk analysis that even in a worst case scenario, where all of the contaminant potentially present within the device coating was released, the levels of contaminant that would be found in the patients bloodstream would be too small to activate the specific chemical messaging system that is associated with the severe allergic-type reactions reported with injectable contaminated heparin.

"Although we believe the risk of severe allergic-type reactions occurring with medical devices containing contaminated heparin is likely to be very small. Clinicians and staff involved in using any medical device containing heparin have already been informed about the issue of potential contamination. This means that the equipment will be used with appropriate precautions. These staff have also been advised to report possible side effects that may be associated with use of these medical devices", Dr Jessamine said.

For more information contact:
Michael Flyger, Communications Advisor, 04-496-2265, 027-434-6878
www.moh.govt.nz/media.

Please note - Dr Jessamine is only available for interviews this afternoon (Friday 23 May)

Background

Contamination with oversulfated chondroitin sulfate has affected the global supply of heparin. It has been established that no contaminated heparin injection product has been distributed in New Zealand, and measures are in place to ensure that no contaminated product enters the supply chain here.

Injectable heparin products contaminated with oversulfated chondroitin sulfate have been associated with serious anaphalactoid and allergic-type adverse reactions and deaths internationally. Research has indicated that these reactions occur due to the activation of a specific chemical messenger system associated with allergic-type reactions and that a certain minimum plasma (blood) level of contamination is required to activate this chemical pathway.

Medsafe has not received any reports of adverse reactions definitively caused by the use of heparin-containing medical devices. However, the level of reassurance this provides is limited by contaminated devices only recently entering the supply chain and the small number that have been used.

An example of a medical device that is in patient contact and contains heparin is a cardiac oxygenator. It has a coating of heparin bonded to the surface, to prevent the coagulation (clotting) of blood being passed through the machine during cardiac surgery. There is no test that can be performed on a medical device to determine whether or not it contains contaminated heparin. This determination can only be made by tracing and testing the batch of heparin used in the manufacture of the medical device.

Heparin is also used in some brands of test tubes and containers used to collect blood for testing in biochemistry laboratories. Manufacturer testing of these have indicated that several brands contain contaminated heparin. Preliminary research by these manufacturers however report that the presence of oversulfated chondroitin sulfate at levels of contamination up to 1% is not associated with clinically significant changes in the accuracy of the results obtained for close to all routine blood tests.

This is an international problem and Medsafe is working with overseas regulators to identify the scope of the problem and take appropriate action. Further information will be provided as it becomes available.

In response to this emerging safety issue Medsafe has taken a number of actions including:
convening an expert group to provide practical, clinical, ethical and scientific advice to the Director-General of Health in relation to the identification, assessment and management of risk associated with contaminated heparin that has been, or may have been, used in the manufacture of medical devices supplied in New Zealand;
working closely with international agencies to ensure New Zealand is taking similar steps to those taken overseas to protect patients;
alerting manufacturers, suppliers and importers of medical devices to the issue of use of contaminated heparin and requiring them to supply Medsafe with any information they hold about the safety of the heparin they have used to enable Medsafe to introduce risk management strategies around the possible further import of contaminated devices; and
communicating with health professionals to ensure they are aware of the best advice on the issue as it comes to hand.

Further information

Further information on this issue can be found at:

www.medsafe.govt.nz
www.fda.gov/cdrh/safety/heparin-device-list.html (FDA list of affected devices)
www.fda.gov/cdrh/safety/heparin-notice.html (FDA notice to medical device manufacturers and distributors)

ENDS


What has the heparin become contaminated with?
The heparin has become contaminated with oversulfated chondroitin sulfate.

What is oversulfated chondroitin sulfate?
Oversulfated chondroitin sulfate mimics heparin's qualities and is a modified form of chondroitin sulfate. Chondroitin sulfate is a naturally occurring substance made from animal cartilage and is often used in supplements to treat arthritic joints.

How does this affect its safety and/or effectiveness of treatments?
Injectable heparin contaminated with this ingredient has caused severe adverse reactions (anaphylaxis and hypotension) and deaths internationally. Injectable heparin contaminated with oversulphated chondroitin sulfate is not used in New Zealand.
The risk to patients is regarded as very low. There have been no reports in New Zealand or internationally of harm conclusively linked to use of a medical device containing the contaminated heparin.

In most cases the heparin found in medical devices is bound to the surface of the devices as a coating designed to stop blood clotting on the devices itself.

As only small amounts of heparin are used in these devices and the heparin coating is not designed to dissolve away, any contaminant that may be present would not be expected to be released into the patient’s bloodstream.
It is unclear what effect on treatment the contaminated heparin will have.

Are other heparin products affected - for example heparin supplied in syringes or saline?
No, these are medicines and there no contaminated medicine has been supplied in New Zealand.

What is heparin used for in medical devices?
It is applied as a coating to prevent blood clotting. The coating designed to stick to the product and not to dissolve.

What alternatives, if any, are available?
There are other products from other manufacturers which may potentially be used; however it is not known whether the fittings on these devices are compatible with other devices needed to carry out surgery. Further research is being carried out to establish whether these products can be used.

How long until we get alternative supplies of contaminant-free heparin coated devices?
Indications from Medtronic, the manufacturers of the devices containing contaminated heparin are that it will be at least 2-3 months before stocks of medical devices containing uncontaminated heparin are available.

Who is Medsafe working with to ensure as much as possible is known about the problem?
Medsafe is working with regulators around the world including the US Food and Drug Administration. A Technical Advisory Group is being convened to provide expert clinical advice on the issue.


ENDS

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