Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 56 3 2018 03 06 210 213 EN Aghygh Heidari Department of Anesthesiology, Imam Ali Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran Feridoun Sabzi Department of Cardiovascular Surgery, Imam Ali Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran. 2016 09 29 2017 04 30 Here we report a case of postoperative thrombocytopenia (TTP) in a 77-year-old case that has been undergoing  mitral valve replacement with combined coronary  artery bypass grafting. In the 5th days of operation, his platelet count was reduced and despite platelet transfusion, his platelet count reaches to a minimum level of 15000 µg/mL on the 34th day of surgery. Despite platelet transfusion and plasmapheresis, platelet count continues to decrease and signs and symptoms of disseminated intravascular coagulation appeared by unexpectable renal and pulmonary bleeding.  Finally high dose, steroid therapy was started and after some days, platelets count raised to 80000 µg/mL. DIC was recovered, but  acute renal failure  did not respond to medical and hemodialysis and the case expired with sudden cardiac arrest and ventricular fibrillation.we conclude that if  the  diagnosis of TTP was made earlier in the course of disease by consulting internist  and steroids was instituted  it might prevent  ARF and its poor outcome. https://acta.tums.ac.ir/index.php/acta/article/view/5906 https://acta.tums.ac.ir/index.php/acta/article/download/5906/5071