From the Editor

Activated factor VII proves to be a lifesaver in postpartum hemorrhage

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A patient bleeding to death following delivery is every OB’s greatest fear


 

References

Obstetricians train relentlessly to respond to severe postpartum hemorrhage in a systematic manner by sequentially intervening with tocolytics, massive transfusion of blood products, surgical procedures (including hysterectomy and pelvic packing1), and consultation with interventional radiologists, if available (TABLE). Even with optimal therapy, however, postpartum hemorrhage remains a major cause of maternal death throughout the world.2

TABLE

At your disposal, a range of interventions for obstetric hemorrhage

PHARMACOTHERAPY
CarboprostOxytocin
MethergineVasopressin
MisoprostolRecombinant human factor VIIa*
BLOOD BANKING
CryoprecipitatePlatelets
Fresh-frozen plasmaRed blood cells
SURGERY
Repair of lacerationsLigation of the hypogastric artery
B-Lynch sutureOther uterine compression sutures
Hysterectomy, supracervicalPelvic packing
Hysterectomy, totalPelvic tourniquet
NONSURGICAL PROCEDURES
Bakri balloonUterine packing
Uterine balloon tamponade
INTERVENTIONAL RADIOLOGY
Uterine artery balloonsUterine embolization
CONSULTATION
Anesthesiologist–intensivistTrauma surgeon
Gynecologic oncologistUrologist
Interventional radiologist
*Not approved by the FDA for this indication.

Evidence is growing that recombinant activated clotting factor VII (or rF-VIIa) is a potentially life-saving treatment for women with severe postpartum hemorrhage who are not responding to standard interventions. How does this agent work in such cases?

The coagulation cascade is complex. An abbreviated version reveals the therapeutic role that exogenous rF-VIIa may play:

  1. F-VII binds to tissue factor (TF) that has been exposed on damaged blood vessels and other cells, resulting in activation of the protease function of F-VII
  2. The TF–F-VIIa complex directly activates F-IX and F-X
  3. This activation accelerates the conversion of prothrombin to thrombin and, in turn, of fibrinogen to fibrin
  4. The enzymatic process is markedly enhanced by the action of platelet membranes.

In massive trauma or severe postpartum hemorrhage, exogenous rF-VIIa may enhance complexing of TF and F-VIIa on damaged cells, thereby accelerating clotting locally and reducing the magnitude of blood loss.

Evidence of efficacy

rF-VIIa (NovoSeven [Novo Nordisk]) has been approved by the FDA for treating bleeding in (a) patients with hemophilia who have antibodies to F-VIII and F-IX and (b) patients with F-VII deficiency. rF-VIIa is not approved for treating bleeding associated with major trauma or postpartum hemorrhage. However:

  • There are dozens of case reports of patients bleeding to death from severe trauma who apparently have had their life saved by rF-VIIa3
  • One large clinical trial indicates that rF-VIIa is beneficial for hemorrhage caused by trauma.4

In that clinical trial, 301 patients with severe trauma who had received at least 8 units of red blood cells (RBCs) were randomized to standard surgical care plus intravenous injection of placebo or to standard surgical care plus injection of rF-VIIa. Three doses of rF-VIIa were administered: 200 μg/kg after the initial 8 units of RBCs were transfused, 100 μg/kg 1 hour later, and 100 μg/kg 3 hours later. Compared with subjects given placebo injection, those who received rF-VIIa had fewer transfusions and lower rates of massive transfusion (>12 units), acute respiratory distress syndrome, and multiorgan failure.

In patients with blunt trauma, the percentage of subjects who received more than 12 units of RBCs declined from 33% in the placebo group to 14% in the group treated with rF-VIIa. Overall mortality, however, was not significantly reduced by rF-VIIa. Of note, an equal number of thromboembolic events occurred in the group treated with rF-VIIa and the group treated with placebo. (The trial was supported by the manufacturer of rF-VIIa.4)

Strong case evidence in ObGyn but no rigorous trials

Dozens of cases have been reported of women with massive postpartum hemorrhage who apparently had their life saved by rF-VIIa.5-9 rF-VIIa has also been used successfully in severe hemorrhage following gynecologic surgery10 and after amniotic fluid embolism with coagulopathy.11

Regrettably, there are no randomized trials of rF-VIIa in obstetrics to guide your clinical action. In the series cited most often, rF-VIIa was administered after available standard surgical procedures for severe postpartum hemorrhage were used and transfusion had reached the 8- to 30-unit range. This indicates that, in most series, only the most severe cases of postpartum hemorrhage were treated with rF-VIIa. The dose of rF-VIIa in these reports was, typically, in the range of 40 to 120 μg/kg.

An option after others fail

Based on a review of the literature, I propose the following approach to severe postpartum hemorrhage with rF-VIIa when other modalities prove insufficient:

  • Start with a dosage of 40 μg of rF-VIIa/kg of body weight to balance the benefit of hemostasis against the risk of harmful thromboembolic events
  • Because rF-VIIa has a circulating half-life of approximately 2 hours, consider a second dose of rF-VIIa, as was given in many of the reported cases of postpartum hemorrhage.

Note that, before rF-VIIa was administered in most series, standard surgical intervention had included hysterectomy. In 1 report of 4 cases, however, rF-VIIa was used successfully for postpartum hemorrhage after uterine tamponade had failed but before hysterectomy was performed.12

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