Need substitute for Heparin drug for use in valve replacement

[An-Slead]

  We have a serious problem - my mother-in-law had surgery 20 years ago to
  replace one valve in her heart with a mechanical valve.  She has been
  taking Cumadin (coumadin) (blood thinner) since that surgery.Now, she needs more
  surgery to replace two more valves.  She was scheduled for valve
  replacement surgery in July of this year, but the night before they were
  to operate, they found a problem with the way her blood reacts to Heparin.
  As I understand it, she needs to receive Heparin during surgery so that
  she can be hooked up to a heart bypass machine.  However, instead of
  thinning her blood as it should, Heparin causes her blood platelets to
  stick together and form clumps.  The doctors postponed the surgery and
  did tests to see if she has the same reaction to the two other possible
  drugs they could use instead of Heparin. Apparently, her blood reacted
  the same way.  Now her surgery has been cancelled until / unless they can
  find some alternate drug that can be used. Her prognosis isn't good -
  she is 70 years old and we have been told that she will probably live
  6 months to a year without the surgery.  She is retaining fluid at an
  alarming rate, and is taking daily shots of Lasix and Diurel (not sure of
  the spelling, but they are diuretics to keep the fluid down).  Her doctors
  are looking for an alternative drug - maybe something that is being used
  on an experimental basis?  I thought it couldn't hurt to ask for help in
  this forum, also.  Does anyone have any ideas???  Thanks for your help !

[CCF Cardio MD - MTR]

Dear Ann, thank you for your question.  I think that I can help you.  Heparin-Associated Thrombocytopenia (HAT) occurs in ~5% of patients treated with heparin, and as you have found, can complicate future attempts to use heparin.  Heparin is used during cardiopulmonary bypass to thin the blood as it passes through the circuits outside the body that oxygenates the blood while the heart is stopped during surgery.  If heparin can't be used, then another blood thinner must be used or else the blood would clot in the bypass machine rendering it inoperable.  In HAT, an antibody is produced against heparin that causes the platelets to clump and the platelet count to fall precipitously.  If heparin is used again once the diagnosis of HAT is made, the same problem can occur again.  We have physicians here at the Cleveland Clinic who are experts at dealing with this problem and I think they can help you.  Dr. John Bartholomew of our Dept. of Vascular Medicine would be happy to see your mother-in-law or at least speak with you on the phone.  His office phone number is 216-444-0825.  He indicated to me that there are agents other than heparin called danaproid and refludan that have been used here during cardiopulmonary bypass for patients with HAT.   Since your mother-in-law would be facing a complicated redo open-heart surgery, my advice to you would be to seriously consider coming to Cleveland for an evaluation.  Our surgeons are among the world's best and I think your mother-in-law would be in good hands here.  I hope you find this information useful.  Please feel free to write back with more questions.  Information provided in the heart