[Significance and incidence of type II heparin-induced thrombocytopenia. A prospective study].

Aim: The incidence of heparin-induced thrombocytopenia (HIT type II) as a consequence of postoperative thrombosis prophylaxis after hip or knee prosthesis was investigated in this study. Furthermore the platelets count was postoperatively analysed in patients without HIT II.
Patients and Methods: Patients with knee and hip prosthesis were included in a prospective study during an 8 months period. All patients received 3 x 5,000 Liquemin (Hoffmann-LaRoche) from the day of the operation until discharge. In cases with a platelet count drop of more than 40% and in patients with clinically manifest thrombosis or embolism a HIT type II test was initiated.
Results: 5 of 252 patients included in this study developed a HIT type II. The platelet count drop was on average 65.7% (40.9-81.6). One patient died of a lung embolism (lethality 20%). Four patients were treated with Hirudin and 1 patient with Danaproid-Natrium. There was no drop of the platelet count between the 5th and 7th postoperative day of more than 15% in the other patients without HIT type II.
Conclusion: In operative departments not enough attention is paid to HIT type II. Knowing the risks with an appropriate monitoring HIT type II can be early detected. Under these conditions the advantages of a heparin prophylaxis outweigh the risk of developing a HIT type II with it's life threatening sequelae.