Clinical experiences and current evidence for therapeutic recombinant factor VIIa treatment in nontrauma settings

A review of current agents for anticoagulation for the critical care practitioner

There has been a tremendous boom in the arena of anticoagulant therapy recently. Although the indications for these agents reside in the noncritical care environment, over time, the impact of these agents have infiltrated the critical care environment particularly due to devastating complications with associated use. With so many newer agents on the market or coming down the pipeline, it is easy to become overwhelmed. It is important that the critical care practitioner does not ignore these agents but becomes familiar with them to better prepare for the management of patients on one or more anticoagulant agents in the intensive care unit. To equip the critical care practitioners with the knowledge about commonly used anticoagulants, we provide an extensive review of the pharmacology, indications, and adverse effects related to these agents as well as suggestions on preventing or managing complications.

Recombinant activated factor VII use in critically ill patients: clinical outcomes and thromboembolic events

BACKGROUND

Hemorrhage and coagulopathy are associated with morbidity and mortality in critically ill patients. Recombinant activated factor VII (rFVIIa) is frequently used in these situations to control bleeding; however, few controlled clinical trials have demonstrated clinical benefit and prolonged survival.

OBJECTIVE

To compare clinical outcomes and thromboembolic events in intensive care unit (ICU) patients who received rFVIIa versus ICU patients who did not between 2000 and 2005.

METHODS

A total of 2918 nonhemophiliac adult ICU patients, which included 1459 who received at least 1 dose of rFVIIa and 1459 matched controls who did not, were included in a retrospective database study. Data were extracted from the Solucient ACTracker database, which included 550 hospitals across the US. Measures included patient demographics, rFVIIa prescribing, death, thromboembolic events, discharge disposition, length of stay, and transfusion data.

RESULTS

The most common primary diagnoses for patients receiving rFVIIa included traumatic brain injury, cirrhosis, and nontraumatic intracranial hemorrhage. Patients receiving rFVIIa were more likely to have comorbidities, including mechanical ventilation, acute kidney injury, sepsis, hemodialysis, and gastrointestinal bleeding (p < 0.0001). The average rFVIIa dose was 4.8 mg and 82% of patients received 1 dose. Compared to controls, patients receiving rFVIIa had greater odds of death (OR 2.1, 95% CI 1.8-2.6, p < 0.0001), transfusion (OR 2.1, 95% CI 1.8-2.5, p < 0.0001), and longer length of stay (p < 0.001). There was no significant difference in thromboembolic events between groups.

CONCLUSIONS

While we cannot show direct causality between rFVIIa and the poor clinical outcomes documented in ICU patients, they provide important insight for critical care clinicians.

Effect of haemodilution, acidosis, and hypothermia on the activity of recombinant factor VIIa (NovoSeven)

Background

A range of plasma volume expanders is used clinically, often in settings where haemostasis may already be impaired. The haemostatic agent, recombinant activated factor VII (rFVIIa, NovoSeven^®), may be used to improve haemostasis but potential interactions with different volume expanders are poorly understood.

Methods

Clot formation was measured by thromboelastography (TEG) using blood from healthy volunteers. In vitro effects of rFVIIa with haemodilution, acidosis, and hypothermia were examined. Conditions were induced by dilution with NaCl (0.9%), lactated Ringer's solution, albumin 5%, or hydroxyethyl starch (HES) solutions [MW (molecular weight) 130–670 kDa]; by adjusting pH to 6.8 with 1 M HEPES (N-2-hydroxyethylpiperazine-N′-2-ethanesulphonic acid) buffer; or by reducing temperature to 32°C. We also studied the effect of low vs high MW HES (MW 200 vs 600 kDa) and rFVIIa on in vivo bleeding time (BT) in rabbits.

Results

Haemodilution progressively altered TEG parameters. rFVIIa improved TEG parameters in the presence of acidosis, hypothermia or 20% haemodilution (P<0.05). At 40% haemodilution, the rFVIIa effect was diminished particularly with high MW HES. In vivo, rFVIIa shortened the BT (P<0.05) with low but not high MW HES.

Conclusions

Efficacy of rFVIIa was affected by the degree of haemodilution and type of volume expander, but not by acidosis or hypothermia.

Hemostatic therapy for the treatment of intracranial hemorrhage

Intracranial hemorrhage results in poor neurologic outcomes and high mortality. Current management is limited to supportive care. In addition to the initial bleeding event, rebleeding and hematoma expansion have been identified as major risk factors for poor outcomes in these patients. The antifibrinolytic agents tranexamic acid, aminocaproic acid, and recombinant activated factor VII (rFVIIa) have been studied with the hopes of achieving early hemostasis and improving outcomes. Available data suggest that tranexamic acid and aminocaproic acid are more harmful than beneficial for this indication; therefore, they have no role in the treatment of intracranial bleeding. Alternatively, rFVIIa, has shown promising results in the management of spontaneous intracerebral hemorrhage. Clinicians should be aware of the available evidence regarding the use of these hemostatic agents in the management of intracranial hemorrhage, including traumatic brain injury, intracerebral hemorrhage, and subarachnoid hemorrhage.

Recombinant factor VIIa treatment for life-threatening haemoptysis

Diffuse alveolar haemorrhage is a severe clinical disorder that may be life-threatening. The early diagnosis of diffuse alveolar haemorrhage and prompt intervention is crucial. Recombinant factor VIIa has been used extensively for the treatment of haemophilia A and B patients. More recently, recombinant factor VIIa has been used successfully for the treatment of bleeding in patients without pre-existing coagulopathy. We describe the successful use of recombinant factor VIIa in a patient with diffuse alveolar haemorrhage secondary to pulmonary-renal syndrome.