Rapid correction of prothrombin time after low-dose recombinant factor VIIA in patients undergoing orthotopic liver transplantation

Coagulopathy in liver disease

The liver plays a central role in hemostasis, as it is the site of synthesis of clotting factors, coagulation inhibitors, and fibrinolytic proteins. The most common coagulation disturbances occurring in liver disease include thrombocytopenia and impaired humoral coagulation. Therapy's overall goal is not to achieve complete correction of laboratory value abnormalities but to gain hemostasis. Therapy with vitamin K may be a useful option in patients with increased prothrombin time due to vitamin K deficiency; in patients with malnutrition; in patients using antibiotics; and in patients with cholestatic liver disease, particularly prior to invasive procedures. Infusion of fresh frozen plasma is more often effective and is recommended in patients with liver disease before invasive procedures or surgery, as such patients require transient correction in their prothrombin time. Therapy with plasma exchange may be considered in patients who cannot be treated with fresh frozen plasma due to volume overload risk. In patients with severe coagulopathy and hypofibrinogenemia, cryoprecipitate therapy is ideal. Therapy with prothrombin-complex concentrate is seldom pursued in patients with liver disease due to high risk of thrombotic complications. Transfusions of platelets are appropriate for patients with thrombocytopenia (< 50,000/mm(3)) associated with active bleeding or before invasive procedures in which a short-term platelet count increase is noted. Trial with desmopressin may be considered before invasive procedures in patients with liver disease and with refractory and prolonged bleeding time. Recombinant activated factor VIIa administration is suggested for patients with significantly prolonged prothrombin time and contraindications to fresh frozen plasma therapy; however, this is expensive. Thrombopoietin and interleukin-11 are currently investigational for patients with thrombocytopenia of chronic liver disease. Liver transplantation completely restores impaired coagulation abnormalities and is the ultimate intervention that corrects coagulopathy of advanced liver disease and liver failure.

Recombinant activated factor VII in liver patients: a retrospective cohort study from Australia and New Zealand

Recombinant factor VIIa (rFVIIa) is used in the treatment of life-threatening haemorrhage that is refractory to conventional treatment. The evidence supporting this practice in patients with liver disease is very limited. It has been used as a salvage therapy in end-stage liver disease (ESLD), in orthotopic liver transplant (OLT), other surgery, and upper gastrointestinal bleeding (UGIB) subpopulations. It has also been used prior to procedures in patients with ESLD. Data were collected by the Australia and New Zealand Haemostasis Registry (ANZHR) to perform a retrospective cohort study on the different subgroups of liver patients. This included 115 cases of use of rFVIIa in liver patients from 20 hospitals. A retrospective cohort study on the different subgroups of liver patients was performed. Main outcome measures were reduction or cessation of bleeding and 28-day mortality. Variables previously shown to predict response to bleeding after administration of rFVIIa were examined to determine whether correlations exist. Salvage therapy with rFVIIa was associated with reduction or cessation in bleeding in 24 of 36 OLT patients, 24 of 36 UGIB patients and 15 of 26 of other surgery patients. Clinical response to rFVIIa in OLT patients and other surgery patients was associated with a significantly lower mortality compared to nonresponders (P = 0.003 and 0.022, respectively). There was no relationship between mortality and bleeding response in patients with UGIB. Variables including acidosis, hypothermia, hypofibrinogenaemia, thrombocytopenia and Model of End-Stage Liver Disease (MELD) score were not associated with clinical response to rFVIIa. Five cases of use prior to procedures are described. Recombinant FVIIa is used as rescue therapy in surgical patients with ESLD and refractory haemorrhage in Australia and New Zealand. Traditional haemostasis variables were not associated with clinical response to rFVIIa in this cohort. Response to rFVIIa is associated with decreased mortality in ESLD patients undergoing OLT and other surgery, but not in UGIB.

Low-dose recombinant factor VIIa for trauma patients with coagulopathy

INTRODUCTION

Coagulopathy in injured patients is common and is generally treated with fresh frozen plasma (FFP). Response can be variable, thus complete correction may take hours and require large volumes of fluids. High-dose recombinant factor VIIa (FVIIa, Novoseven, Novo Nordisk, Bagsvaerd, Denmark) has been used off-label to treat severe coagulopathy following trauma. Expense has limited use. Recently, we began administering low dose FVIIa (1.2mg) to patients with mild to moderate coagulopathy after trauma, hypothetising that it would be effective and safe.

PATIENTS AND METHODS

We retrospectively reviewed consecutive patients who received a low dose of 1.2mg of FVIIa over a 2-year period. Factor VIIa is administered after approval by a gatekeeper at the discretion of the treating physician. Demographics, injury and laboratory data were abstracted as were indications for use, source of coagulopathy, effectiveness, and complications. A two-tailed paired t-test was used to determine significant changes in coagulation parameters and blood product utilisation.

RESULTS

Eighty-one patients received 84 low doses of FVIIa. The mean age of the patients was 51 (+/-22) with a mean ISS of 29 (+/-11). Seventy-three per cent were male and 67% had a traumatic brain injury (TBI) as their primary injury. The aetiology of the coagulopathy in the study population included; TBI (40%), warfarin use (22%), and cirrhosis (13%). Mean prothrombin time (PT) fell from 17.0 s (+/-3.2) to 10.6s (+/-1.4) (p<0.0001). All patients had a good clinical response with no bleeding complications. Utilisation of packed red blood cells and fresh frozen plasma were significantly less in the 24h after FVIIa administration as compared to the 24h prior. Subsequent thromboembolic events were observed in 12 of the 81 patients (15%) and included; cerebrovascular accident (CVA) (6), mesenteric thrombosis (2), myocardial infarction (MI) (1), pulmonary embolism/deep venous thrombosis (PE/DVT) (2), and atrial thrombus (1). Only four of these events were thought to be related to the FVIIa administration, with two of the four contributing to a lethal outcome.

CONCLUSIONS

Low dose FVIIa rapidly and effectively treats mild to moderate coagulopathy following injury. This low dose (1.2mg) FVIIa is the smallest available unit dose. It costs approximately the same as 8 units of plasma and may be cost-effective in patients who require high volume factor administration. Low dose FVIIa may be effective in coagulopathic trauma patients who are not in shock but require rapid normalisation of clotting function.

Activated recombinant factor VII in orthotopic liver transplantation

Orthotopic liver transplantation (OLT) is affected by important alterations of hemostasis. The aim of this study was to evaluate the efficacy of recombinant factor VII activated (rFVIIa) to reduce intraoperative bleeding during OLT.

METHODS

Twenty OLT patients were assigned in double-blind way to a rFVIIa group or a control group. Inclusion criteria were hemoglobin > 8 g/dL: INR > 1,5 and fibrinogen > 100 mg/dL. We administered a single bouls of rFVIIa (40 microg/kg) or placebo. We determined INR, partial thromboplastin time, fibrinogen, ATIII, and blood cell counts. Blood products were administered as follows: 4 units of fresh frozen plasma when INR > 1.5, and 1 unit of RBC for Hb < 10 g/dL. The study ended 6 hours after the bolus.

RESULTS

No thromboembolic events occurred. The INR was different between rFVIIa group and the controls at T0 (1.9 vs 1.6 P < .021) and during T1 (1.2 vs 1.6 P < .004). The total transfused red blood cells was 300 mL +/- 133 in rFVIIa group and 570 mL +/- 111 in control group (P < .017). The total fresh frozen plasma was 600 mL +/- 154 in rFVIIa group and 1400 mL +/- 187 in control group (P < .001). Total blood loss was greater in the control group than the rFVIIa group: 1140 mL +/- 112 vs 740 mL +/- 131 (P < .049).

DISCUSSION

The use of rFVIIa during OLT can reduce the risk of bleeding during surgery. The literature has described cases who did not benefit from the treatment. An adequate cut-off of INR, allowed us to treat only patients at greater bleeding risk.

Early postoperative hemorrhage requiring urgent surgical reintervention after orthotopic liver transplantation

Hemorrhage is a common complication in the early postoperative period after orthotopic liver transplantation (OLT) and surgical reintervention may be necessary. We sought to assess the incidence as well as to identify potential risk factors for bleeding requiring surgical reintervention in the early postoperative period. From January 2003 to December 2005, we retrospectively reviewed the courses of 261 patients who underwent OLT. We analyzed the pretransplantation parameters, transplantation features, and clinical data for surgical reintervention due to early postoperative hemorrhage. Twenty-two of 261 patients (8.4%) had early postoperative hemorrhage requiring urgent surgical reintervention during the initial hospital stay. In-hospital mortality of the patients with hemorrhage (9/22; 41%) was significantly higher than that of other patients (29/239; 12.1%; P < .001). The surgical problem was the main cause of hemorrhage (18/22; 81.8%). More intraoperative blood transfusions were necessary for patients with hemorrhage than for other patients. Furthermore, a greater number of blood transfusions, including red blood cells, plasma, and platelet concentrates, during the transplantation procedure correlated with a greater mortality. In conclusion, early postoperative hemorrhage requiring urgent surgical reintervention is a severe complication with a high mortality. It is mainly caused by errors in surgical technique. Blood transfusion during transplantation was correlated with a higher mortality.

Recombinant factor VIIa reduces transfusion requirements in liver transplant patients with high MELD scores

Patients undergoing orthotopic liver transplantation (OLT) often experience significant coagulopathy and remain at risk for excessive blood loss and massive transfusion. The ability of recombinant factor VIIa (rFVIIa) to reduce transfusion requirements during OLT has not been well established. This retrospective study investigates whether rFVIIa reduces transfusion requirements in liver transplant patients with a significantly prolonged prothrombin time (PT) and a model of end-stage liver disease (MELD) score of > 20. Eleven patients received a single dose of rFVIIa (58 +/- 18 microg kg(-1)) at the time of incision. This group was matched with a selected control group that fulfilled all of the inclusion/exclusion criteria. Patient characteristics, pre-operative PT, HCT, PLT and MELD were identical between groups. Prophylactic application of rFVIIA reduced packed red blood cells (3.9 +/- 2.6 versus 6.9 +/- 2.3 U, P = 0.01) and fresh-frozen plasma (FFP) (12.6 +/- 6 versus 19.8 +/- 7 U, P = 0.018) transfusion requirements when compared with the control group. FFP administration in the first 24 h after surgery was also significantly less in the rVIIa group when compared with the control group (388 +/- 385 versus 1225 +/- 701 mL, P = 0.003). Hospital stay following transplantation tended to be shorter in the rFVIIa group, albeit statistical significance was not achieved (11 +/- 7.3 versus 7.9 +/- 2.7, P = 0.2). All but one patient in the control group survived for 30 days after transplantation. In a selected group of patients with prolonged PT and high MELD score, the prophylactic application of rFVIIa at the start of the OLT may reduce perioperative transfusion requirements.

Liver Transplantation for Fulminant Hepatic Failure Without Venovenous Bypass and Without Portacaval Shunting

Preservation of the caval vein during liver transplantation (OLT) has gained wide acceptance but portosystemic bypass or temporary portocaval shunt is still believed to be indicated in patients with fulminant hepatic failure. Herein we have described our initial experience with piggyback OLT without venovenous bypass and without portocaval shunting in five such patients. Division of the portal vein was always delayed until the native liver was completely dissected off the caval vein. The donor hepatic artery was anastomosed to the recipient aorta via an iliac interposition graft placed in the supraceliac position in two and at an infrarenal site in three patients. The ahepatic phase urinary output was low in the two patients in whom we applied supraceliac cross-clamping of the aorta. The mean ahepatic phase was 53 (45 to 67) minutes in four recipients who remained hemodynamically stable throughout surgery and prolonged to 5 hours in one patient due to a complicated supraceliac aortic anastomosis. Its repair resulted in hemodynamic instability, multiorgan failure, and death at 4 days following OLT. Four (80%) patients are alive in good condition with normal liver function after a mean of 12 (5 to 25) months of follow-up. In summary, liver transplantation for fulminant hepatic failure may be safely performed without venovenous bypass and without temporary portocaval shunting if the ahepatic phase is minimized and portal flow to the liver maintained up to the moment of hepatic excision. Arterial anastomosis with the supraceliac aorta prolongs the ahepatic phase and may impair kidney function: therefore, it should be avoided in these patients.

Management of bleeding emergencies: when to use recombinant activated Factor VII

Recombinant activated Factor VII (rVIIa) was originally released as a clotting factor, with use limited to a select group of patients who had few other treatment options. Due to the apparent ability of rVIIa to stop bleeding, no matter what the underlying cause, there is great interest in use of rVIIa in a wide range of bleeding patients. This article discusses rVIIa and its uses in a variety of patients, especially liver disease and trauma patients, and makes suggestions for appropriate use. Although most of the reports on rVIIa are anecdotes and case series, there is increasing data for clinical trials to help guide usage.

The Effect of In Vitro Recombinant Factor VIIA on Coagulation Parameters for Blood Taken During Liver Transplantation

Recombinant factor VIIa (rFVIIa) has been utilized in pilot studies in orthotopic liver transplantation (OLT) when administered to patients at doses of 68.37 microg/kg and 80 microg/kg. Although some effectiveness in normalizing measurements of coagulation has been demonstrated, the optimal dose for patients undergoing OLT has not been established. This study evaluated the effects of an in vitro equivalent dose of 120 microg/kg of rFVIIa on coagulation parameters when applied to the blood drawn from patients undergoing OLT. Coagulation function was assessed in 10 patients at four points during OLT. These time points were baseline, 5 minutes prior to reperfusion, 10 minutes after reperfusion, and 70 minutes after reperfusion. These patients did not receive rFVIIa perioperatively. At each of these four time points, a native sample was analyzed for prothrombin time (PT) and thromboelastogram. The rFVIIa (6.1 microg/kg or the approximate equivalent dose of 120 microg/kg for a 70 kg patient) was added to a second sample from the same patient. This second sample was also analyzed for PT and thromboelastogram. There was a statistically significant difference in baseline PT between native versus rFVIIa supplemented samples (15.8 +/- 3.21 vs 13.6 +/- 2.36 seconds, P < .02). The maximum amplitude of the thromboelastogram was larger in the native samples at 5 minutes prior to reperfusion (53.5 mm vs 39 mm, P < .02). No significant differences existed in the variables at any of the other sampling times. This study failed to demonstrate a consistent in vitro effect of rFVIIa on the blood taken from patients during OLT.

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

The hemostatic properties of recombinant activated factor VII (rFVIIa) are established in patients with inherited or acquired hemophilia with inhibitors and in patients with congenital factor VII deficiencies. Emerging clinical evidence suggests that there may be a wider role for rFVIIa in the management of hemorrhage associated with traumatic injury/accident and severe bleeding associated with critical surgery. This article considers recent data from studies in which rFVIIa was used in an attempt to control bleeding in clinical situations as diverse as coagulopathy associated with chronic liver disease, massive perioperative bleeding and bleeding during prostatectomy, organ transplantation and orthopedic surgery, uncontrollable obstetric hemorrhage, and intracerebral hemorrhage. In nontrauma settings involving acute and potentially life threatening bleeding, there may be a place for rFVIIa as adjunctive therapy in the control of hemostasis.

Hemostatic defects in end stage liver disease

End stage liver disease results in a complex and variably severe failure of hemostasis that predisposes to abnormal bleeding. The diverse spectrum of hemostatic defects includes impaired synthesis of clotting factors, excessive fibrinolysis, disseminated intravascular coagulation, thrombocytopenia, and platelet dysfunction. Hemostasis screening tests are used to assess disease severity and monitor the response to therapy. Correction of hemostatic defects is required in patients who are actively bleeding or require invasive procedures. Fresh frozen plasma, cryoprecipitate, and platelet transfusion remain the mainstays of therapy until larger trials confirm the safety and efficacy of recombinant factor VIIa in this population.

Uses of recombinant factor VIIa in trauma

PURPOSE OF REVIEW

Despite advances in the care of the injured, the morbidity and mortality of traumatic hemorrhage remain a significant problem. Traumatologists continue to look for ways to treat bleeding and prevent the sequelae of hemorrhagic shock. Recombinant factor VIIa, developed for the treatment of patients with hemophilia, has been used with some success in acute bleeding associated with injuries.

RECENT FINDINGS

The mechanism of action is via a tissue factor-dependent effect and/or platelet activation. Coagulation occurs at the site of tissue injury, where tissue factor is exposed. Case series have described the beneficial effects of recombinant factor VIIa in the treatment of acute hemorrhage, early treatment of traumatic brain injury, and reversal of premorbid anticoagulation. In addition, there have been numerous reports of recombinant factor VIIa use in acute bleeds secondary to other causes as well as some evidence that recombinant factor VIIa may be efficacious when used prophylactically in high-risk patients and for high-risk procedures. Typical doses range from 50 to 100 microg/kg as a single bolus. Although there has been concern over the risk of inappropriate thrombosis with recombinant factor VIIa administration, this complication has seldom been described in published series.

SUMMARY

Although case experience is encouraging, no level 1 evidence has been published that demonstrates clinical or economic benefit of the use of recombinant factor VIIa in trauma patients. Many questions remain to be answered, ideally through randomized, prospective clinical trials. In particular, the issues of patient selection, ideal dosing, and factors associated with futile administration need to be elucidated.

Emerging Off-Label Uses for Recombinant Activated Factor VII: Grading the Evidence

Recombinant activated factor VII (rFVIIa) is currently licensed in the United States for treatment of bleeding episodes in patients with deficiencies of factor VIII (FVIII) or IX (FIX) who are refractory to factor replacement because of circulating inhibitors. A 1999 report of its successful use to stop what was deemed to be lethal hemorrhage after an abdominal gunshot wound in a young soldier without pre-existing coagulopathy has prompted exploration of other uses for rFVIIa. The virtual explosion of proposed uses of rFVIIa raises issues not only regarding our understanding of the coagulation system, but also regarding its efficacy, cost-effectiveness, and safety.

Effect of Activated Recombinant Human Factor 7 (Niastase) on Laboratory Testing of Inhibitors of Factors VIII and IX

Activated recombinant human factor VIIa (rFVIIa) has been used as a hemostatic agent in patients with hemophilia and acquired inhibitors. Other indications for rFVIIa may include liver disease, warfarin sodium (Coumadin) overdose, or trauma. Monitoring patients on this treatment with standard laboratory testing is problematic. Bleeding risk does not correlate well with the prothrombin time (PT) or the activated partial thromboplastin time (aPTT) during therapy with rFVIIa. In addition, there is no identifiable literature on the effect of rFVIIa on assays of inhibitors in this patient group. Monitoring inhibitors may be important during interventions aimed at acutely reducing inhibitor levels, such as during plasma exchange or protein adsorption. We performed factor assays and evaluated inhibitor levels in plasma from 3 patients with deficiencies in FVIII (2 patients) or FIX (1 patient) and inhibitors (titer range, 5.8-17.4 Bethesda units) before and after adding rFVIIa (range, 0.25-8 microg/mL) in vitro. Additionally, we performed assays of factors of both intrinsic and extrinsic systems to determine the impact of rFVIIa on these tests. We found that both factor levels and inhibitor titers from patients with hemophilia A or B could be measured accurately, even in the presence of suprapharmacologic doses of rFVIIa (8 microg/mL). We also obtained accurate measurements for other assays of the intrinsic coagulation system (FXI and FXII) based on the aPTT. Conversely, we found that assays of the extrinsic system based on the PT (FII, FV, and FX) produced results that were unreliable. FVII results were very high but reproducible. These results suggest that assays based on the PT are inaccurate and should be avoided during FVIIa treatment. Conversely, FVIII and FIX levels and inhibitor titers can be accurately monitored in hemophilia patients receiving rFVIIa according to results of aPTT-based coagulation tests.