Recombinant activated factor VIIa in uncontrolled bleeding: a haemostasis laboratory study in non-haemophilia patients

Extensive surgery and massive tissue trauma are often associated with severe bleeding. We present retrospective data on the use of recombinant factor VIIa in haemostatic emergencies in13 non-hemophilia patients with uncontrolled bleeding. Recombinant factor VIIa was administered in doses ranging from 16 mug/kg bodyweight to 60 microg/kg bodyweight. Blood loss during 24 h before and after the infusion was registered, showing that 10 out of 13 patients (77%) had a 70% or greater reduction in transfusion requirement decreasing significantly in mean from 28.1 to 9.9 red blood cell units. Coagulation parameters were studied in blood samples collected 10 min before and 10-15 min after the injection of recombinant factor VIIa. Factors VII:C, II:C, and X:C increased significantly while the activated partial thromboplastin time, platelet numbers, and concentration of fibrinogen and D-dimers were unchanged. The dose of rFVIIa correlated significantly with the rise in factor X:C and inversely with transfusion requirements. Dynamic clot velocity of whole blood was recorded before and after rFVIIa infusion in four patients. Judged from red blood cell usage no improvement in haemostasis was seen in one patient suffering thrombocytopenia and low fibrinogen. This patient died 6 h after recombinant factor VIIa infusion, and three other patients died before 1 month. None of the fatalities appeared to be related to recombinant factor VIIa usage. No thromboembolic complications were seen. In conclusion, 12 out of 13 patients survived the first 24 h after treatment with relatively low doses of recombinant factor VIIa for large-scale bleeding. Recombinant factor VIIa was well tolerated and safe in these non-hemophilia patients. With quite low doses of recombinant factor VIIa (<or= 60 microg/kg), the dose of recombinant factor VIIa correlated positively with efficacy. Activation of factor X appeared to predict haemostatic efficacy.

Recombinant activated factor VII for bleeding in patients without inherited bleeding disorders

(1) Recombinant activated factor VII (rFVIIa) is licensed in Canada for the prevention and treatment of bleeding in hemophiliacs, but it is increasingly used to control bleeding in non-hemophilic patients during surgery, or during treatment for severe trauma or intracerebral hemorrhage (ICH). (2) In one clinical trial, there was a significant reduction in mortality among patients with ICH treated with rFVIIa. In another trial, administration of rFVIIa significantly reduced the number of trauma patients needing massive blood transfusions although there was no significant difference in mortality. (3) Adequately powered randomized controlled trials are needed to clarify the efficacy and safety of rFVIIa for non-bleeding disorder indications. Phase III trials in ICH and trauma are underway. (4) There is potential for non-hemophilic use, particularly if clinical efficacy and cost effectiveness are established.

Safety and hemostatic effect of recombinant activated factor VII in cirrhotic patients undergoing partial hepatectomy: a multicenter, randomized, double-blind, placebo-controlled trial

BACKGROUND

Coagulopathy caused by cirrhosis may contribute to excessive bleeding during hepatectomy. We evaluated the hemostatic effect and safety of recombinant factor VIIa (rFVIIa) in cirrhotic patients undergoing partial hepatectomy.

METHODS

Patients were randomized to rFVIIa 50 or 100 mug/kg or placebo, administered intravenously 10 minutes before surgery and every second hour during surgery. The primary efficacy end points were the proportion of patients receiving red blood cell (RBC) transfusions and the amount of RBCs transfused. The RBC transfusion trigger was blood loss of 500 mL. Safety end points included thromboembolic and adverse events.

RESULTS

No statistically significant effect of rFVIIa treatment on efficacy end points was observed. Serious and thromboembolic adverse events occurred at similar incidences in the study groups.

CONCLUSIONS

Using blood loss as a transfusion trigger, the efficacy of rFVIIa in reducing the requirement for RBC transfusion was not established in this study. No safety concerns were identified.

A prospective randomized trial of high and standard dosages of recombinant factor VIIa for treatment of hemarthroses in hemophiliacs with inhibitors

AIM

A multicenter randomized open-label crossover prospective trial was designed to compare the efficacy, safety, and cost of standard and high dosages of recombinant factor VIIa (rFVIIa) for home treatment of hemarthroses in hemophiliacs with inhibitors.

METHODS

Patients were instructed to treat, within 6 h from the onset of bleeding, four consecutive hemarthroses of ankles, knees, or elbows, either with the rFVIIa standard dose of 90 microg kg(-1) (repeated as necessary every 3 h) or with a single high dose of 270 microg kg(-1). Patients who did not achieve a clinical success within 9 h continued rFVIIa treatment with repeated standard doses. Response to treatment was assessed for up to 48 h by patients/caregivers, who reported on a Visual Analogue Scale (VAS) graded from 0 to 100 the improvement in symptoms and also rated the responses as effective, partially effective or ineffective. Success was defined a treatment course rated as effective and with a VAS score > or =70 and failure a treatment course rated as ineffective and VAS score < or =30, whereas treatment courses that did not fulfill these criteria were considered partial responses.

RESULTS

Twenty hemophiliacs with inhibitors were originally enrolled (median age: 27 years), 18 of them treated 32 hemarthroses assigned to the standard-dosage and 36 to the high-dosage regimen, during the study period of 18 months. Forty-eight hemarthroses (71%) occurred in target joints. Success rates for standard- and high-dosage regimens were similar: 31% and 25% at 9 h, 53% and 50% at 24 h, 66% and 64% at 48 h, the end point for outcome assessment. The median number of rFVIIa infusions needed to achieve a successful course was significantly greater for the standard-dosage (n = 3) than for the high-dosage regimen (n = 1), and the median amount of rFVIIa ultimately used per successful course was identical (270 microg kg(-1)).

CONCLUSION

Our results indicate that a high-dosage regimen with rFVIIa for home treatment of hemarthroses is effective, safe, does not imply an increased consumption of rFVIIa and requires the infusion of a smaller number of rFVIIa doses. Its convenience is particularly relevant in cases with difficult venous access and in hemorrhages into target joints.

Thromboembolic adverse events after use of recombinant human coagulation factor VIIa

CONTEXT

The US Food and Drug Administration (FDA) licensed recombinant human coagulation factor VIIa (rFVIIa) on March 25, 1999, for bleeding in patients with hemophilia A or B and inhibitors to factors VIII or IX. Use in patients without hemophilia has been increasing since licensure.

OBJECTIVE

To review serious thromboembolic adverse events (AEs) reported to the FDA's Adverse Event Reporting System (AERS).

DESIGN, SETTING, AND PATIENTS

The AERS database was reviewed from March 25, 1999, through December 31, 2004, for thromboembolic AE reports with rFVIIa. The AERS database includes US and non-US spontaneous AE reports from both approved (specific indications for patients with hemophilia) and unlabeled uses. It also includes serious AEs in patients enrolled in postlicensure clinical trials who received rFVIIa. Manufacturer reporting to FDA is mandatory, but primary notification from clinicians and others to FDA or manufacturers is voluntary for spontaneous reports; therefore, AERS underrepresents actual event occurrences.

MAIN OUTCOME MEASURE

Reported thromboembolic events occurring in patients administered rFVIIa.

RESULTS

A total of 431 AE reports for rFVIIa were found, of which 168 reports described 185 thromboembolic events. Seventeen events occurred in patients with hemophilia and 59 occurred in patients enrolled in postlicensure trials. Unlabeled indications accounted for 151 of the reports, most with active bleeding (n = 115). Reported AEs were thromboembolic cerebrovascular accident (n = 39), acute myocardial infarction (n = 34), other arterial thromboses (n = 26), pulmonary embolism (n = 32), other venous thromboses (including deep vein thrombosis) (n = 42), and clotted devices (n = 10). In 36 (72%) of 50 reported deaths, the probable cause of death was the thromboembolic event. In 144 patients with timing information, 73 events (52%) occurred in the first 24 hours after the last dose (30 events within 2 hours). Sixty-four reports (38%) noted concomitant use of hemostatic agents. Most reports lacked sufficient information to evaluate potential dosage associations.

CONCLUSIONS

Most reported thromboembolic AEs followed the use of rFVIIa for unlabeled indications and occurred in arterial and venous systems, often resulting in serious morbidity and mortality. Analysis of the relationship between AEs and rFVIIa is hindered by concomitant medications, preexisting medical conditions, confounding by indication, and inherent limitations of passive surveillance. Randomized controlled trials are needed to establish the safety and efficacy of rFVIIa in patients without hemophilia.

A prospective pilot study of prophylactic treatment of preterm neonates with recombinant activated factor VII during the first 72 hours of life

OBJECTIVE

Intraventricular hemorrhage (IVH) in the preterm infant is a devastating complication, causing marked mortality and morbidity. A general hemostatic agent such as recombinant activated factor VII (rFVIIa) might have the potential to reduce the extent of severe IVH.

DESIGN

Prospective, single-arm pilot study.

SETTING

Level III neonatal intensive care unit.

PATIENTS

Ten preterm infants between 23 and 28 wks of gestation.

INTERVENTION

Administration of a 100-microg/kg rFVIIa bolus injection within the first 2 hrs of life, followed by 100 microg/kg rFVIIa every 4 hrs, for the first 72 hrs of life.

MEASUREMENTS AND MAIN RESULTS

Cranial ultrasonography and flow studies of the major arteries and the venae cava, aorta, vena portae, and venae renales, was performed at study enrollment and at 12 hrs, 24 hrs, 48 hrs, and 72 hrs. Blood cell counts and coagulation studies were performed. End points of the study were occurrences of adverse events, with an emphasis on thrombotic events or disseminated intravascular coagulation (DIC). Ten preterm infants with a gestational age of 23 wks 1 day to 28 wks 3 days were included. None had venous thrombosis or cerebral infarction during or after the treatment. Neither platelet consumption nor DIC was observed. Two infants with an umbilical artery catheter had a thrombus at the catheter tip (one during infusion of the study drug), which was successfully treated with heparin. One had grade III IVH and died on day 6 of life; in another, grade II IVH progressed to grade III after termination of the drug.

CONCLUSION

One hundred microg/kg rFVIIa does not accumulate if administered prophylactically to preterm infants of <28 wks of gestation every 4 hrs in the first 72 hrs of life. In this population, rFVIIa does not cause DIC. Thrombus formation was observed in two infants with umbilical artery catheters but in none of the infants with venous catheters. Embolic events were not observed. In this pilot study, which did not provide the sample size to assess any effect of rFVIIa on the incidence of IVH, 20% of the neonates went on to have grade III or IV IVH, which is similar to the rate in studies in which rFVIIa was not given.

A multicenter assessment of recombinant factor VIIa off-label usage: clinical experiences and associated outcomes

BACKGROUND

Off-label use of recombinant factor VIIa (rFVIIa) occurs despite minimal data. The purpose of this study was to describe prescribing practices and clinical outcomes for off-label rFVIIa use.

STUDY DESIGN AND METHODS

A retrospective, multicenter chart audit of 315 nonhemophiliac patients was performed.

RESULTS

Off-label indications included prevention of bleeding primarily related to procedural manipulation in 37.8 percent of patients and treatment of bleeding in 62.2 percent of patients. Baseline coagulopathy was present in 79.7 percent of patients. Prescriber specialty varied. The median doses for prevention and treatment were 75.6 and 89.4 microg per kg, respectively (p = 0.0006). The international normalized ratio (INR) decreased (p < 0.0001) from baseline in both groups. Transfusions of blood products were provided to 85.1 percent of patients before rFVIIa administration with considerable practice variation. Few patients received other procoagulant agents. In the prevention group, 14.3 percent of patients bled within 6 hours of their procedure. No variable was independently associated with bleeding prevention. In the treatment group, 52.6 percent of patients stopped bleeding within 6 hours of rFVIIa administration. The only independent variable associated with bleeding cessation was an arterial pH value of less than 7.20, which was a negative predictor (odds ratio, 0.207; 95% confidence interval, 0.084-0.507). Possible rFVIIa-associated adverse events occurred in 9.8 percent of patients and primarily involved undesirable clotting. No variable was independently associated with adverse events.

CONCLUSIONS

Off-label use of rFVIIa includes prevention and treatment of bleeding. rFVIIa is associated with INR reduction. Bleeding is rare with prophylactic rFVIIa but the cessation of bleeding is less than reported in the literature and may be related to pH. Possible adverse events are related to undesirable clotting.

The safety and efficacy of the administration of recombinant activated factor VII in major surgery and trauma patients

Recombinant activated Factor VII (rFVIIa) has been successfully used in the treatment of haemophilia A and B with associated inhibitors for some years. Activated Factor VII binds to activated platelets independently of tissue factor. The resulting stimulation of an exaggerated early thrombin burst at sites of vascular injury makes it an attractive potential treatment for massive, uncontrolled bleeding associated with surgery and trauma. This article describes the evidence relating to surgery and trauma. The lack of large, controlled trials of rFVIIa means that a definitive recommendation regarding its use cannot be made at present. However, in the context of clearly defined protocols and balanced treatment strategies, rFVIIa may have a role in traumatic bleeding. Large scale, randomised controlled trials in trauma are required, as is further work on the safety profile of rFVIIa with an independent international safety monitoring committee.

Recombinant factor VIIa (NovoSeven) as a hemostatic agent after surgery for congenital heart disease

BACKGROUND

Postoperative bleeding and blood product requirements can be substantial in children undergoing open-heart surgery, and reexploration is required in 1% of cases. Recombinant activated factor VII (rFVIIa, NovoSeven, NovoNordisk, Denmark) is a hemostatic agent approved for the treatment of hemophilic patients with inhibitors to factor VIII or factor IX. It has also been used with success in other conditions. We present our experience with rFVIIa treatment for uncontrolled bleeding after open-heart surgery in five pediatric patients.

METHODS

The study group consisted of five patients after open-heart surgery with excessive blood loss. The patients were treated with rFVIIa after failure of conventional treatment to control the bleeding. Blood loss, blood product consumption, and coagulation test results were recorded before and after rFVIIa administration.

RESULTS

In all cases, blood loss decreased considerably after rFVIIa administration (mean 7.8 ml x kg(-1) x h(-1)), almost eliminating the need for additional blood products, and the prolonged prothrombin time normalized. In two patients with thrombocytopathy, rFVIIa helped to discriminate surgical bleeding from bleeding caused by a defect in hemostasis. No side effects of rFVIIa treatment were noted.

CONCLUSIONS

These cases support the impression that RFVIIa is efficient and safe in correcting hemostasis in children after cardiopulmonary bypass when other means fail. However, the data are still limited, and more extensive research is needed.

Recombinant activated factor VII for acute intracerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage is the least treatable form of stroke and is associated with high mortality. Among patients who undergo computed tomography (CT) within three hours after the onset of intracerebral hemorrhage, one third have an increase in the volume of the hematoma related to subsequent bleeding. We sought to determine whether recombinant activated factor VII (rFVIIa) can reduce hematoma growth after intracerebral hemorrhage.

METHODS

We randomly assigned 399 patients with intracerebral hemorrhage diagnosed by CT within three hours after onset to receive placebo (96 patients) or 40 microg of rFVIIa per kilogram of body weight (108 patients), 80 microg per kilogram (92 patients), or 160 microg per kilogram (103 patients) within one hour after the baseline scan. The primary outcome measure was the percent change in the volume of the intracerebral hemorrhage at 24 hours. Clinical outcomes were assessed at 90 days.

RESULTS

Hematoma volume increased more in the placebo group than in the rFVIIa groups. The mean increase was 29 percent in the placebo group, as compared with 16 percent, 14 percent, and 11 percent in the groups given 40 microg, 80 microg, and 160 microg of rFVIIa per kilogram, respectively (P=0.01 for the comparison of the three rFVIIa groups with the placebo group). Growth in the volume of intracerebral hemorrhage was reduced by 3.3 ml, 4.5 ml, and 5.8 ml in the three treatment groups, as compared with that in the placebo group (P=0.01). Sixty-nine percent of placebo-treated patients died or were severely disabled (as defined by a modified Rankin Scale score of 4 to 6), as compared with 55 percent, 49 percent, and 54 percent of the patients who were given 40, 80, and 160 microg of rFVIIa, respectively (P=0.004 for the comparison of the three rFVIIa groups with the placebo group). Mortality at 90 days was 29 percent for patients who received placebo, as compared with 18 percent in the three rFVIIa groups combined (P=0.02). Serious thromboembolic adverse events, mainly myocardial or cerebral infarction, occurred in 7 percent of rFVIIa-treated patients, as compared with 2 percent of those given placebo (P=0.12).

CONCLUSIONS

Treatment with rFVIIa within four hours after the onset of intracerebral hemorrhage limits the growth of the hematoma, reduces mortality, and improves functional outcomes at 90 days, despite a small increase in the frequency of thromboembolic adverse events.

Recombinant Coagulation Factor VIIa in Major Liver Resection

Background

Prevention of bleeding episodes in noncirrhotic patients undergoing partial hepatectomy remains unsatisfactory in spite of improved surgical techniques. The authors conducted a randomized, placebo-controlled, double-blind trial to evaluate the hemostatic effect and safety of recombinant factor VIIa (rFVIIa) in major partial hepatectomy.

Methods

Two hundred four noncirrhotic patients were equally randomized to receive either 20 or 80 microg/kg rFVIIa or placebo. Partial hepatectomy was performed according to local practice at the participating centers. Patients were monitored for 7 days after surgery. Key efficacy parameters were perioperative erythrocyte requirements (using hematocrit as the transfusion trigger) and blood loss. Safety assessments included monitoring of coagulation-related parameters and Doppler examination of hepatic vessels and lower extremities.

Results

The proportion of patients who required perioperative red blood cell transfusion (the primary endpoint) was 37% (23 of 63) in the placebo group, 41% (26 of 63) in the 20-microg/kg group, and 25% (15 of 59) in the 80-microg/kg dose group (logistic regression model; P = 0.09). Mean erythrocyte requirements for patients receiving erythrocytes were 1,024 ml with placebo, 1,354 ml with 20 microg/kg rFVIIa, and 1,036 ml with 80 microg/kg rFVIIa (P = 0.78). Mean intraoperative blood loss was 1,422 ml with placebo, 1,372 ml with 20 microg/kg rFVIIa, and 1,073 ml with 80 microg/kg rFVIIa (P = 0.07). The reduction in hematocrit during surgery was smallest in the 80-microg/kg group, with a significant overall effect of treatment (P = 0.04).

Conclusions

Recombinant factor VIIa dosing did not result in a statistically significant reduction in either the number of patients transfused or the volume of blood products administered. No safety issues were identified.

Safety and Feasibility of Recombinant Factor VIIa for Acute Intracerebral Hemorrhage

Background and Purpose— Hematoma growth occurs in 38% of intracerebral hemorrhage (ICH) patients scanned by computed tomography (CT) within 3 hours of onset. Activated recombinant factor VII (rFVIIa) promotes hemostasis at sites of vascular injury and may minimize hematoma growth after ICH.

Methods— In this randomized, double-blind, placebo-controlled, dose-escalation trial, 48 subjects with ICH diagnosed within 3 hours of onset were treated with placebo (n=12) or rFVIIa (10, 20, 40, 80, 120, or 160 μg/kg; n=6 per group). The primary endpoint was the frequency of adverse events (AEs). Safety assessments included serial electrocardiography (ECG), troponin I and coagulation testing, lower extremity Doppler ultrasonography, and calculation of edema:ICH volume ratios.

Results— Mean age was 61 years (range, 30 to 93) and 57% were male. At admission, mean National Institutes of Health Stroke Scale (NIHSS) score was 14 (range, 1 to 26), median Glasgow Coma Scale score was 14 (range, 6 to 15), and mean ICH volume was 21 mL (range, 1 to 151). Mean time from onset to treatment was 181 minutes (range, 120 to 265). Twelve serious AEs occurred, including 5 deaths (mortality 11%). Six AEs were considered possibly treatment-related, including rash, vomiting, fever, ECG T-wave inversion, and 2 cases of deep vein thrombosis (placebo and 20-μg/kg groups). No myocardial ischemia, consumption coagulopathy, or dose-related increase in edema:ICH volume occurred.

Conclusion— This small phase II trial evaluated a wide range of rFVIIa doses in acute ICH and raised no major safety concerns. Larger studies are justified to determine whether rFVIIa can safely and effectively limit ICH growth.

Recombinant factor VIIa for intractable blood loss after cardiac surgery: a propensity score-matched case-control analysis

BACKGROUND

Cardiac surgery is occasionally complicated by massive blood loss that is refractory to standard hemostatic interventions. Recombinant factor VIIa (rF-VIIa) is being increasingly used as rescue therapy in such cases, but little information is available on its safety and efficacy for this indication.

STUDY DESIGN AND METHODS

The outcomes of the first 51 cardiac surgery patients who received rF-VIIa for intractable blood loss (from November 2002 to February 2004) at a single institution according to a standardized clinical guideline were compared to 51 matched control patients, with the control patients identified from a large database and matched based on the propensity for massive blood loss.

RESULTS

Blood loss and blood product usage were significantly decreased after 2.4 to 4.8 mg of rF-VIIa. In those treated after sternal closure (n = 32), there was a significant reduction in blood loss from the hour before to the hour after treatment: 100 (70, 285) mL (median [25th, 75th percentiles]; p < 0.0001). Except for a slower postoperative recovery and higher incidence of acute renal dysfunction, the adverse event rates were similar between the rF-VIIa-treated patients and their matched controls.

CONCLUSIONS

These results suggest that rF-VIIa may be an effective rescue therapy for patients with intractable hemorrhage after cardiac surgery. A clinically important risk of stroke or other major thrombotic complications could not be ruled out by our study. Controlled clinical trials with adequate power to detect the impact of rF-VIIa therapy on morbidity and mortality therefore are necessary before one can recommend its routine use in patients undergoing cardiac surgery who have excessive bleeding.

Intérêt du facteur VII activé recombinant dans l’hémorragie de la délivrance sévère réfractaire à la prise en charge conservatrice conventionnelle

Postpartum haemorrhage remains the main cause of maternal morbidity and mortality. Treatment aims at maintaining hemodynamic circulation and preventing shock by stopping blood loss both medically and surgically. We report two cases of major postpartum haemorrhage due to uterine atony. Patients developed haemorrhagic shock and severe coagulation disorders (nadir values of PTT were <10% and fibrinogen was <0.1 g/l). Well-codified medical (ocytocin, sulprostone) and surgical management (ligation of both hypogastic arteries in the two cases completed by staged uterine ligation in one case) failed to stop bleeding. Recently, several case reports described successful use of recombinant activated factor VII (rFVIIa) in scheduled surgery, trauma and major postpartum haemorrhage. Thus, after transfusion of more than one blood mass and failure of surgical haemostasis to stop bleeding, rFVIIa (60 microg/kg) was given. A single iv bolus injection stopped ongoing diffuse haemorrhage in the two cases. No further transfusion was required afterwards in both patients. RFVIIa might thus be a strong complementary agent in the management of major postpartum haemorrhage. Optimal dose, timing and safety characteristics of rVIIa administration remain to be determined. One patient developed four weeks later thrombosis of both ovarian veins, a complication that can be related to either rFVIIa or to the staged uterine ligations performed during surgery.

Recombinant factor VIIa for upper gastrointestinal bleeding in patients with cirrhosis: a randomized, double-blind trial

BACKGROUND & AIMS

Upper gastrointestinal bleeding (UGIB) is a severe and frequent complication of cirrhosis. Recombinant coagulation factor VIIa (rFVIIa) has been shown to correct the prolonged prothrombin time in patients with cirrhosis and UGIB. This trial aimed to determine efficacy and safety of rFVIIa in cirrhotic patients with variceal and nonvariceal UGIB.

METHODS

A total of 245 cirrhotic patients (Child-Pugh < 13; Child-Pugh A = 20%, B = 52%, C = 28%) with UGIB (variceal = 66%, nonvariceal = 29%, bleeding source unknown = 5%) were randomized equally to receive 8 doses of 100 microg/kg rFVIIa or placebo in addition to pharmacologic and endoscopic treatment. The primary end point was a composite including: (1) failure to control UGIB within 24 hours after first dose, or (2) failure to prevent rebleeding between 24 hours and day 5, or (3) death within 5 days.

RESULTS

Baseline characteristics were similar between rFVIIa and placebo groups. rFVIIa showed no advantage over standard treatment in the whole trial population. Exploratory analyses, however, showed that rFVIIa significantly decreased the number of failures on the composite end point (P = 0.03) and the 24-hour bleeding control end point (P = 0.01) in the subgroup of Child-Pugh B and C variceal bleeders. There were no significant differences between rFVIIa and placebo groups in mortality (5- or 42-day) or incidence of adverse events including thromboembolic events.

CONCLUSIONS

Although no overall effect of rFVIIa was observed, exploratory analyses in Child-Pugh B and C cirrhotic patients indicated that administration of rFVIIa significantly decreased the proportion of patients who failed to control variceal bleeding. Dosing with rFVIIa appeared safe. Further studies are needed to verify these findings.

Recombinant activated factor VII decreases bleeding without increasing arterial thrombosis in rabbits

PURPOSE

To compare the effects of recombinant activated factor VII (rFVIIa) and platelet-rich plasma (PRP) in an experimental model of bleeding and arterial thrombosis.

METHODS

The Folts model was used in 60 rabbits. After anesthesia, the carotid artery was exposed and a 75% stenosis was induced. A compression injury of the artery triggered a series of cyclic flow reductions (CFRs). After counting baseline CFRs, animals were assigned randomly to one of four groups (n = 15 in each): control, PRP, rFVIIa and placebo. Control animals received 10 mL.kg(-1) of saline while 10 mL.kg(-1) of a hydroxyethyl starch solution (200,000/6%/0.5) were infused in the three other groups. CFRs were measured again, followed by treatment with PRP, rFVIIa or placebo and by a final measurement of CFRs. At the end of each observation period, an ear immersion bleeding time (BT) was measured and a blood sample was drawn for the evaluation of hematological variables. Microvascular bleeding was evaluated at the end of the experiment in grams of blood shed from liver and spleen sections. Results are presented as median (range).

RESULTS

rFVIIa shortened the BT and decreased microvascular bleeding as compared with placebo [60 (35-100) sec vs 110 (50-140) sec, P = 0.0019 and 9 (4-24) g vs 17 (5-28) g, P = 0.002, respectively]. rFVIIa did not increase CFRs [3(0-9) vs |(0-5), P = 0.11].

CONCLUSION

rFVIIa led to a decrease in BT and microvascular bleeding but did not significantly affect arterial thrombosis in rabbits.