A 42-year-old woman complains about bruises on her both legs and prolonged menstruation; general weakness, tinnitus cerebri. Objectively: multiple macular hemorrhages on the legs and body. The patient presents with tachypnoe, tachycardia, systolic murmur in all auscultatory points. AP- 75/50 mm Hg. Blood count: RBC - 1,9 × 1012/l, Hb- 60 g/l, colour index - 0,9, WBC - 6,5 × 109/l, thrombocytes - 20 × 109/l, ESR - 12 mm/h. Duke bleeding time - 12 minutes. Bone marrow analysis revealed plenty of juvenile immature forms of megacaryocytes without signs of thrombocyte pinch-off. What is the most likely diagnosis?