There are a few reports of cardiac surgery in patients with myelodysplastic syndrome (MDS). It is difficult to control bleeding and prevent infection in the presence of pancytopenia. Interstitial pneumonia, which is treated by steroid medication, is also a risk factor in cardiac surgery. Aortic valve replacement was successfully performed in a patient with severe thrombocytopenia associated with MDS, interstitial pneumonia and scleroderma.