Al Have You Seen This Article Yet?

[Ross]

Heparin Antibodies May Pose Risk In Heart Surgery Patients

http://www.sciencedaily.com/print.php?url=/releases/2005/12/051203122633.htm

[allodwick]

I haven't seen the article, but I have talked with Tom Ortel (the last author listed) about this problem last May when we were at a meeting in Orlando. They are talking about Heparin-Induced Thrombocytopenia (HIT). I take care of several people who have had this. I have one who went to a major medical center to get a mechanical valve. She did get it but she ended up losing her right leg from the knee down and the tip of her tongue to HIT.

[Lynlw]

Little Katie has that. Lyn

[gijanet]

Just what I wanted to read. Course we did fall into the "greater than 10 day hospital stay" category, didn't we? Sure glad we didn't fall into the "other" category!!!! :eek: Thanks, though, for posting this as there doesn't seem to be a lot of info out there on HIT. And thanks, Lyn, for remembering my Katie. dunno where you store all of this, but you amaze me! Hugs to all. J.

[Ross]

The article was sent to me courtesy of Praline. ;)

[Marge]

I was tested for heparin antibodies before my valve surgery because of a prior episode during which gangrene developed in my left arm after I was given heparin during a hospitalization in the 1970s. Back then nobody was talking about HIT -- I wasn't told whether this was due to HIT and still don't know.
I am thankful that I learned about HIT prior to my valve surgery-- I actually learned about it from this board -- from Al and some members who had had experience with HIT.
Thanks to what I learned here I was able to bring the subject up with my surgeon. When I told him about the prior episode, he immediately agreed I needed to be tested by a hematologist prior to the valve surgery.
I actually had two types of tests. PF-4-heparin antibody testing was deemed insufficient to predict the risk of thrombosis. So I also had a 14-C serotonin release assay test. (Don't ask me what all this means!)
Both tests proved negative and I had no problem with heparin therapy during the hospitalization -- but I am glad we had them done.
My hematologist gave me a summary of a study of the use of heparin in patients who have had an episode of HIT. Since it might be of interest, here it is:
<<USE OF HEPARIN AFTER AN EPISODE OF HIT. Patients with a history of HIT who require cardiopulmonary bypass (CPB) have been successfully anticoagulated with unfractionated heparin without complications. This approach is based on the theory that a secondary immune response after rexposure to heparin should not occur until at least three days after exposure. Therefore, a brief exposure to heparin during CPB should not immediately elicit HIT antibodies. Further, since the heparin would be rapidly cleared after the procedure, even if antibodies appeared, they would not be thrombogenic in the absence of heparin.
This approach was tried in 10 patients with a history of HIT who required CPB. At the time of surgery all patients were negative for HIT antibodies according to a PF 4 solid phase assay. There were no complications of surgery, no prolonged thrombocytophenia, and no increase in the serum concentration of HIT antibodies during a 10-day post-operative period.>>

[allodwick]

HIT wasn't clearly defined until about 10 years ago.

The antibodies do go away - just like the antibodies for tetanus and so you need another tetanus shot.

One thing that was missing in the summary was that if you had heparin in the last 3 months, HIT can develop immediately when it is restarted because you may have the antibodies but they just did not develop full-blown HIT on the first exposure.