Most common causes of death are Within 1 month: Primary graft failure, ischemia and reperfusion injury, and infection (eg, pneumonia) excluding cytomegalovirus Between 1 month and 1 year: Infection After 1 year: Obliterative bronchiolitis Mortality risk factors include cytomegalovirus mismatching (donor positive, recipient negative), human leukocyte antigen (HLA-DR) mismatching, diabetes, and prior need for mechanical ventilation or inotropic support.