Recombinant factor VIIa in a patient with Glanzmann’s thrombasthenia undergoing gynecological surgery: open issues in light of successful treatment

The Evidence for the Use of Recombinant Human Activated Factor VII in the Treatment of Bleeding Patients With Quantitative and Qualitative Platelet Disorders

There are increasing reports suggesting that high-dose recombinant human activated factor VII (rFVIIa) is effective in the treatment and prevention of bleeding in patients with quantitative and qualitative platelet disorders. These clinical observations are supported by evidence that FVIIa binds weakly to activated platelet surface and at high concentration improves thrombin generation. In experimental models, this improved thrombin generation enhances platelet adhesion in thrombocytopenic conditions and enhances adhesion and aggregation of platelets lacking glycoprotein IIbIIIa (integrin alpha(IIb)beta(3)), characteristic of the qualitative platelet disorder Glanzmann thrombasthenia (GT). There is a need for clinical trials to confirm the safety and efficacy of rFVIIa in patients with various quantitative and qualitative platelet defects, either by itself or in combination with other hemostatic agents such as platelet transfusion. Pending the availability of such data, rFVIIa may be considered in severe bleeding in thrombocytopenia and GT patients with platelet antibodies and refractory to platelet transfusions and other standard treatments. An international survey suggests that rFVIIa at about 90 microg/kg every 2 hours for 3 or more doses could be used for GT patients with severe bleeding, but confirmation by larger studies is needed. For GT patients undergoing surgery and for treatment and prevention of bleeding in thrombocytopenic patients, the optimal rFVIIa regimen remains to be defined.

Recombinant activated factor VII for hemostatic cover of orthopedic interventions in a girl with thrombocytopenia with absent radii syndrome

Over the past 10 years recombinant activated factor VIIa (rFVIIa) has been successfully used for treatment and prophylaxis of bleeding in patients with platelet defects, including thrombocytopenia and congenital and acquired platelet function abnormalities. Most reported data concern patients with Glanzmann's thrombasthenia and the information available is still limited, especially for surgery. We report on a 15-year-old girl with thrombocytopenia ( approximately 60,000/microl) and platelet dysfunction (bleeding time 30 min, absent platelet aggregation and ATP secretion in response to collagen), related to thrombocytopenia with absent radii syndrome, undergoing two surgical interventions on the upper limbs due to forearm deformities, with prolonged postoperative revisions. In both surgeries rFVIIa was successfully employed as a bolus administration (80 microg/kg every 4 h during the first day, then every 6 h over the following 5 and 3 days, respectively; tranexamic acid was associated from the second day, administered for 2 weeks), avoiding the need for blood products. This report highlights rFVIIa as an attractive, alternative approach to secure hemostasis in patients with platelet defects; on the other hand, the heterogeneity of reported rFVIIa treatment regimens and, in particular, the lack of definite and easily available parameters (or assays) for monitoring rFVIIa efficacy and safety are the main open issues in this setting.

The use of recombinant activated factor VII in obstetric and gynaecological haemorrhage

Recombinant activated factor VII (rFVIIa) was originally developed for the treatment of bleeding in patients with haemophilia A or B and inhibitors. Over the past ten years, it has been successfully used to prevent or control bleeding in several other nonhaemophilic bleeding conditions. Among the newer 'off-label' clinical applications of rFVIIa, there is increasing evidence of its effectiveness in treating obstetric and gynaecological bleeding unresponsive to conventional therapy. The existing literature on the use of rFVIIa in obstetrics and gynaecology is summarised in this review. Although supported by few and uncontrolled studies, on the whole, the published data suggest a potential role of rFVIIa in the management of obstetric and gynaecological intractable bleeding. However, further evidence is needed to improve the assessment of its optimal dose, effectiveness and safety in such conditions.

Monitoring survival and function of transfused platelets in Glanzmann thrombasthenia by flow cytometry and thrombelastography

Patients with Glanzmann thrombasthenia (GT) may form isoantibodies which induce refractoriness or inhibition of function of transfused platelets. We monitored the survival and function of transfused platelets by flow cytometry and thrombelastography in a patient with GT. Gating on CD42a+ allowed identification of even a few transfused platelets. Only by gating on these CD41+ CD42a+ cells were we able to demonstrate their capability to bind fibrinogen and PAC-1 upon activation. Platelets were rapidly cleared from the circulation as a result of boosted isoantibodies. The contribution of transfused platelets to clot formation was also demonstrated by thrombelastography by blocking their function with abciximab.

Inherited Platelet Disorders

The inherited platelet disorders are a heterogeneous collection of rare diseases that are infrequently encountered in clinical practice. They are, however, fascinating abnormalities, which have taught us a great deal about normal platelet biochemistry and physiology. In this section of the presentation we will review disorders of the platelet membrane, platelet granule packaging disorders, the hereditary macrothrombocytopenias, platelet signaling disorders and disorders of platelet coagulant function. The molecular basis of the disorders, the cardinal features of their clinical presentation and best methods to make their diagnosis and the latest information regarding therapy will be presented.