HAT TYPE-II AND PLATELETS WITHIN A NORMAL RANGE

The immunological type of heparin-associated thromocytopenia (HAT II) is a severe complication of heparin treatment and is associated with a rterial and venous thrombosis. Only patients with absolute thrombocyto penia have prompted suspicion of HAT in clinical practice. We report o n a 44-year-old male who developed thromboembolic episodes after coron ary angiography such as reinfarction and thrombotic episodes of A. bra chialis. Fibrinolytic therapy combined with i. v. unfractionated hepar in treatment was the therapy of choice and was followed by severe furt her thromboembolic adverse effects. Besides an impaired fibrinolytic r esponse and elevated antiphospholipid antibodies, we diagnosed HAT typ e II In HIPA and ELISA (Stage, Boehringer-Mannheim). This special pati ent had platelet counts within a normal range, when developing the thr omboembolic episodes. It appears that the normal platelet count during the thromboembolic episodes reflect a relative thrombocytopenia. From a clinical point of view we recommend the use of a lab panel to exclu de HAT type II in patients with thromboembolic episodes under therapy with fractionated or unfractionated heparin. Platelet counts within a normal range are not absolute exclusion criterion for HAT II.