Heparin-related thrombosis despite normal platelet counts in vascular surgery

Replacement of unfractionated heparin by low-molecular-weight heparin for postorthopedic surgery antithrombotic prophylaxis lowers the overall risk of symptomatic thrombosis because of a lower frequency of heparin-induced thrombocytopenia

“…‡Two UFH-treated patients developed pulmonary embolism (both day 10), and 1 LMWH-treated patient developed acute coronary syndrome (day 7 6 that formation of platelet-activating HIT antibodies can be associated with thrombosis even in the absence of a significant platelet count fall. Second, among the 87.7% of study patients who underwent serologic testing for HIT antibodies, there was approximately a 60% lower seroconversion rate with LMWH compared with UFH (55.6% and 64.7% by the platelet activation assay and immunoassay, respectively).…”

Heparin‐induced thrombocytopenia and thrombosis

“…Platelet levels decrease by at least 50% from the preheparin value in nearly all patients with HIT. Those who have high platelet levels initially can develop HIT while the platelet count is still within the normal range [13,14]. The duration of heparin exposure and the onset of thrombocytopenia were analyzed in 243 patients by Warkentin and Kelton [11].…”

A Case of Acute Coronary Artery Occlusion Associated with Very Rapid Onset Heparin-induced Thrombosis without Thrombocytopenia

“…Insignificant thrombocytopenia might be due to the limited activation of platelets in the coronary arteries. A few other cases of heparin-induced thrombosis without thrombocytopenia have been previously described (13)(14)(15). Kawashima et al (15) described a case of myocardial infarction that developed recurrent heparininduced stent thrombosis without thrombocytopenia after an emergency stenting into the left main trunk of the coronary artery.…”