Cryoprecipitate is prepared by a controlled thawing of frozen plasma. The plasma warmed to between 1-6° C. The high molecular proteins remain as precipitate. This precipitate is centrifuged and suspended in about 15ml plasma. Each bag of cryoprecipitate contains about 80-120 units factor VIII, about 150 mg of fibrinogen, von Willebrand’s factor and factor XIII.
- Hypofibrinogenaemia: Fibrinogen deficiency may be congenital or may be seen in disseminated intravascular coagulation. Patinets who have a fibrinogen level below 100mg/ml and are bleeding need cryoprecipitate. Patinets with afibrinogenaemia are at risk of post-surgical bleeding. The clinical picture of dysfibrinogenaemia is less clear but the patients appears to the at risk of bleeding and thrombosis. The risk of thrombosis is not related to fibrinogen replacement therapy. Fibrinogen replacement can be replaced using cryoprecipitate as well as frozen plasma. Cryoprecipitete should be used with the fibrinogen levels is less the 100mg/dL or there is a limit to the volume of fluid the patient can be administered. Plasma can be used for bleeding patients with fibrinogen levels greater than 100mg/dL is there is no restriction on the volume of fluid the patient can receive. One bag of cryoprecipitate increases the fibrinogen level by 70mg for every 5-10kg weight.
- von Willebrand’s Disease: Cryoprecipitate is not virus inactivated and carries a risk of transmission of infection. Certain plasma derived factor VIII concentrates have high levels of von Willebrand’s factor (vWF). Surgical prophylaxis and spontaneous and post traumatic bleeding in a patients von Willebrand’s disease should be treated with plasma derived factor VIII concentrates rich in vWF in addition to DDAVP and fibrinotic agents. Cryoprecipitate may be used in emergency. The relation between the degree of correction of coagulation tests and homeostasis is not consistently documented. The aim of therapy is to control bleeding which has been achieved even with partial correction of factors. The recommended doses vary from 1 bag for every 10 kg per day to 10-12 units every 12 hours. The recommended dose in children is 1 bag for every 6kg 12 hourly (BC Medical Journal 2007; 49:441, Freidman KD, Rogers GM. Inherited Coagulation Disorders. P 1379-1424. Wintrobe’s Clinical Hematology, 12 Edition, 2009).
- Haemophilia A: The dose and duration of therapy needs to be depending on the factor level needed, type of bleeding and the type of surgery. Factor VIII concentrate is the preferred product as it is virus inactivated. Cryoprecipitate is indicated only in an emergency where factors VIII concentrates are not available (see Freidman KD, Rogers GM. P 1379-1424. Inherited Coagulation Disorders.Wintrobe’s Clinical Hematology, 12 Edition, 2009 for dosing)
- Factor XIII Deficiency: A very small amount of factor XIII is needed for homeostasis. Patinets have a high risk of intracranial bleeding. Factor XIII has a long half life and prophylactic therapy is indicated. Factor XIII concentrates is the replacement of choice but where this is not available 1 bag of cryoprecipitets for every 10-20 kg every 3-4 weeks may be used.
Cryoprecipitate depleted plasma is known as cryosupernatant. It is poor in large vWF multimers, factor VIII (about 0.11U/ml) and fibrinogen (unto 70% may remain in the cryosupernatant Br J Haematol 2004:126;11-18). Cryosupernatant has been shown to be superior to frozen plasma in some trials (Br J Haematol 1996;94:383-6). A meta-analysis failed to confirm the superiority (Am J Kidney Dis 2009;53:259-72).