A Case of Covid-19 Patient with Acute Limb Ischemia and Heparin Resistance.

Heparin resistance is an uncommon phenomenon defined as the need for high-dose unfractionated heparin (UFH) of more than 35,000 IU/day to achieve the target activated partial-thromboplastin time ratio or the failure to achieve the desired activated clotting time after a full UFH dose. This rare phenomenon is being more commonly observed in Covid-19 patients in a hypercoagulable state. We describe a Covid-19 patient confirmed by reverse-transcriptase polymerase chain reaction assay, with acute limb ischemia, who developed heparin resistance. The patient was managed by the departments of vascular surgery, anesthesia and intensive care, and the Coagulation Service and Thrombosis Research from San Raffaele Scientific Institute, Milan, Italy.