Heparin-induced thrombocytopenia in acute ischemic stroke: Incidence and clinical features

Abstract

Background and purpose: We estimated the incidence of heparin-induced thrombocytopenia (HIT) in acute ischemic stroke and investigated clinical features of the HIT patients.
Methods: Of 1,078 consecutive patients with acute ischemic stroke, 392 were treated with intravenous unfractionated heparin (UFH). Ten of them showed prominent thrombocytopenia without evident causes and were suspected to have HIT. We studied these 10 patients retrospectively. Clinical diagnosis of HIT was made according to the two scoring systems. Antibodies against heparin-platelet factor 4 complexes in plasma were detected by enzyme-linked immunosorbent assay (ELISA) and were confirmed by ¹⁴C-serotonin release assay.
Results: Eight patients were clinically suspected of having HIT according to both the scoring systems. Of them, serological tests were positive in 2 patients only by ELISA and in 2 by both the assays. Amount of UFH administered was larger in 4 patients with positive serological findings than the others. Three patients developed thromboembolic events. Two patients were died and the remaining 6 patients were dependent at the time of hospital discharge. Clinical severity and outcome of all the 8 patients were unfavorable regardless of serological findings.
Conclusions: Prevalence of HIT was 0.5% after ascertainment by serological assays. One should never neglect this serious complication when treating stroke.