Heparin-inuced thrombocytopenia (HIT) with or without thrombosis (HITT) is thrombocytopenia (low platelet counts) due to the administration of heparin. While it is mainly associated with unfractionated heparin (UFH), it can also occur with exposure to low-molecular weight heparin (LMWH), but at significantly lower rates. Despite the low platelet count, it is a thrombotic disorder, with very high rates of thrombosis, in the arteries with or without venous complications. Of note, the rate of DVT (deep vein thrombosis) is roughly 4 times that of arterial thrombosis, and while thrombocytopenia is the most common "event" in HIT, DVT is in fact the most common complication.