Heparin-Induced Thrombocytopenia: A Serious Complication of Heparin Therapy for Acute Stroke

Abstract

Background: Despite the lack of supporting evidence, unfractionated heparin (UFH) is frequently given to acute ischemic stroke patients. This study was designed to determine the incidence of heparin-induced thrombocytopenia (HIT) during acute stroke and to elucidate the clinical features of stroke patients with HIT. Methods: Of 1,078 consecutive patients with acute ischemic stroke, 392 were given intravenous UFH. Ten of these developed prominent thrombocytopenia without any other underlying etiology; they were suspected of having HIT. These 10 patients were studied retrospectively. The clinical diagnosis of HIT was made according to two published scoring systems. Antiplatelet factor 4/heparin antibodies in the plasma were detected by the enzyme-linked immunosorbent assay (ELISA) and were confirmed by the ¹⁴C-serotonin release assay. Results: Eight patients met the criteria for clinical HIT according to both scoring systems. Of these, serological tests were positive in 2 patients only on ELISA and in 2 patients on both assays. The amount of UFH given was greater in the 4 patients with positive serological findings than in the others (p = 0.043). Three patients developed further thromboembolic events, including 1 patient who developed possible cancer-associated thrombosis. Two patients were dead and the remaining 6 patients were dependent at the time of hospital discharge. The clinical severity and outcome of these patients were relatively unfavorable compared to other acute patients. Conclusions: The prevalence of HIT was 0.5% based on both the clinical scoring systems and serological assays. Monitoring for HIT should be included in the medical management of stroke to avoid further complications.

Heparin‐induced thrombocytopenia

“…Thus, the duration of heparin exposure appears to be one of the major risk factors for developing HIT. We have also investigated the incidence of HIT in acute stroke patients who were treated with UFH in Japan [24]. The incidence of HIT was 0·5% in this patient population, which was consistent with a previous report [25].…”

Heparin-Induced Thrombocytopenia

“…10,11 Superficial vein thrombosis is more common (50%-70%) in women. 1,5,7,8,[12][13][14][15][16][17][18] The great saphenous system is involved in 60% to 80% of the patients, and the small saphenous system in 10% to 20%. 1,7,19,20 Bilateral SVT is reported in 5% to 10% of the patients.…”

“…1,25,36 Superficial vein thrombosis may coexist with DVT in 6% to 53% of the patients presenting with SVT. 4,7,12,15,16,20,[47][48][49][50][51][52][53][54][55][56][57][58] The most common is extension from the great saphenous vein (GSV) into the femoral vein. 20 Superficial vein thrombosis of the GSV above knee is associated with 17% to 19% incidence of DVT whereas SVT confined to the below knee segment has an incidence of association only in 4% to 5% of the patients.…”

Predictors and Outcomes of Suspected Heparin-Induced Thrombocytopenia in Subarachnoid Hemorrhage Patients

“…It is likely that this association is more a reflection on the risk of vasospasm rather than a direct cause. As such, it may either be due to the fact that patients who undergo endovascular treatment for vasospasm routinely receive continuous intra-arterial infusions of heparinized saline (4,000 U/l in our series) via the intra-arterial catheter, which either has greater risk than exposure to LMWH [3], or to the higher dose exposure [12,13], delivery through an intravenous route [14] or that vasospasm possibly results in higher levels of circulating PF4. …”