Alpha-Storage Pool Deficiency of Platelet in a Patient with Valvular Heart Disease / 대한혈액학회지

ABSTRACT

Alpha-storage pool deficiency of platelet is a very rare disorder associated with a variety of conditions, including autoimmune disease, disseminated intravascular coagulation, myeloproliferative disorders, and cardiopulmonary bypass. This bleeding disorder is characterized by a moderate thrombocytopenia and a selective abnormality in platelet alpha-granules. We experienced the first case of alpha-storage pool deficiency of platelet in a 28-year-old male with severe valvular heart disease in Republic of Korea. Two years ago, mitral valve replacement was performed in other university hospital. Since a few months ago, dyspnea was developed and progressively exacerbated. Transesophageal echocardiogram showed severe mitral valve regurgitation and aortic valve regurgitation. He had moderate thrombocytopenia. Bleeding time was prolonged. Peripheral blood smear showed hypogranular platelets with indistinct cell membrane. In bone marrow biopsy, there showed evidence of mild hyperplasia of megakaryocytes. Platelet aggregation test revealed abnormal response to collagen and epinephrine. Electron microscopy of periphral blood showed the vacuolization of alpha- granules of platelets. Following platelet transfusion, double valve replacement could be performed successfully. Six months later, platelet morphology was moderately normalized. But bleeding time and platelet aggregation test were still abnormal.