A 67-year-old male developed acute right lower limb ischemia with absent pulses 8 days after emergency coronary artery bypass surgery.
The platelet count (309 × 109/L) had fallen only minimally (from 330 × 109/L) and the limb ischemia was attributed to either cardiac embolism (secondary to postoperative atrial fibrillation) or local right femoral injury (secondary to recent use of an intra-aortic balloon pump). After limb-salvaging thrombectomy (with intraoperative use of UFH), the patient received postoperative therapeutic-dose UFH monitored by the aPTT. Progressive decline in the platelet count by 78% to 74 × 109/L prompted the diagnosis of HIT, at which time the UFH was switched to danaparoid. Furthermore, vitamin K was given to reverse warfarin anticoagulation. Interestingly, a cool and painful left foot improved rapidly following treatment with vitamin K and danaparoid (not shown on the graph).
Abbreviations: bid, twice-daily; iv ther., intravenous therapeutic-dose; sc, subcutaneous; U, units; UFH, unfractionated heparin.
