Q: 64 year old male with End Stage Renal disease (on hemodialysis) presented to Emergency Room (ER) with chest pain and found to have unstable angina. Patient is known to cardiology service from previous 'cath' three months ago and was advised to go through bypass surgery but he opted for medical management. Now patient is agreeable for surgery. Review of his record showed that 3 months ago while in hospital, he was tested positive for Heparin Induced Thrombocytopenia (HIT). His platelet counts are now normal, but to prepare him for surgery, his HIT panel was send again and found to be stayed positive. All of the following can be used in operation theater (OR) except?
A) preemptive transfusion of platelets
C) Heparin reexposure but with intravenous Epoprostenol
D) Plasma exchange upon initiation of cardiopulmonary bypass (CPB)
Objective of above question is to highlight a less known option, epoprostenol. Epoprostenol is a prostaglandin PGI2 which can be used if heparin is used in a patient with positive HIT panel. Though bivalirudin or Argatroban can be used in this scenario but a surgeon may choose against them due to their inability to reverse the anticoagulant effect at the conclusion of cardiopulmonary bypass (CPB). Another viable option is plasma exchange upon initiation of CPB to reduce the titer of HIT antibodies prior to heparin exposure.
Epoprostenol potently desensitizes platelets during exposure to heparin by inhibiting platelet activation and by increasing intracellular concentrations of platelet cyclic adenosine monophosphate. It is given as an intravenous infusion while CPB runs and till protamine is administered to reverse heparin effect. Pharmacy service should be consulted for protocolized infusion of epoprostenol. The most common side effect is vasoplegia.
Choices A is not a recommended option.
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