The evidence for the use of recombinant factor VIIa in massive bleeding: development of a transfusion policy framework

Anesthesia for Patients with Extensive Trauma

Trauma anesthesiology is a unique and growing subspecialty. With the growing number of adult and pediatric trauma centers in the United States, a thorough understanding of the early management of severely injured patients with trauma is an important aspect of anesthesia. Trauma anesthesiology requires the ability to adapt to different work environments, including the trauma bay, the operating room, and even the intensive care unit, where a patient room may require conversion to an operating suite for emergencies. This article provides a review of the anesthetic management for patients with extensive trauma, focusing on physiology, pharmacology, and bedside management.

Inferior Vena Cava Volume Is an Independent Predictor of Massive Transfusion in Patients With Trauma

OBJECTIVES

Early adequate resuscitation of patients with trauma is crucial in preventing shock and early mortality. Thus, we aimed to determine the performance of the inferior vena cava (IVC) volume and other risk factors and scores in predicting massive transfusion and mortality.

METHODS

We included all patients with trauma who underwent computed tomography (CT) scan of the torso, which included the abdominal area, in our emergency department (ED) from January 2014 to January 2017. We calculated the 3-dimensional IVC volume from the left renal vein to the IVC bifurcation. The primary outcome was the performance of IVC volume in predicting massive transfusion, and the secondary outcome was the performance of IVC volume in predicting 24-hour and 30-day in-hospital mortality.

RESULTS

Among the 236 patients with trauma, 7.6% received massive transfusions. The IVC volume and revised trauma score (RTS) were independent predictors of massive transfusion (adjusted odds ratio [OR]: 0.79 vs 1.86, 95% confidence interval [CI], 0.71-0.89 vs 1.4-2.47, respectively). Both parameters showed the good area under the curve (AUC) for the prediction of massive transfusion (adjusted AUC: 0.83 and 0.82, 95% CI, 0.74-0.92 vs 0.72-0.93, respectively). Patients with a large IVC volume (fourth quartile) were less likely to receive massive transfusion than those with a small IVC volume (first quartile, ≥28.29 mL: 0% vs <15.08 mL: 20.3%, OR: 0.13, 95% CI, 0.03-0.66).

CONCLUSIONS

The volume of IVC measured on CT scan and RTS are independent predictors of massive transfusion in patients with trauma in the ED.

Off-label use of recombinant factor VIIa in two tertiary hospitals in Queensland

BACKGROUND

Recombinant factor VIIa (rFVIIa) is used for many off-label indications without high quality evidence to support its efficacy. The aim of this study was to determine indications for use of off-label rFVIIa, efficacy and safety, and adherence to institutional guidelines.

METHODS

We performed a retrospective review of off-label rFVIIa at two tertiary hospitals from 2007 to 2010.

RESULTS

One hundred forty-five administrations were identified and analysed. Haemorrhage associated with cardiac surgery made up one-third of all rFVIIa usage, with trauma (20%) and other surgery (11%) the next most frequent indications. Compared with all others, cardiac surgery patients were older (60.0 years versus 47.4 years, P < 0.001) and had lower pre-rFVIIa transfusion requirements, a higher subjective response rate (88% versus 46%, P < 0.001) and lower mortality rates (6.1% versus 33%, P < 0.001), but higher rates of arterial thrombormbolic events (16.7% versus 2.1%, P = 0.002). Most patients received only one or two doses (n = 137; 95%), with no subject receiving a third or subsequent dose having an appreciable reduction in bleeding. Only a small number of patients (n = 15; 10.3%) had rFVIIa administered in accordance with our institutions' guidelines.

CONCLUSION

Patients administered rFVIIa for haemorrhage not associated with cardiac surgery were severely unwell. Despite lack of evidence, administration of rFVIIa may be justified by the high mortality rate, but more than two doses are unlikely to provide further benefit. The high rate of arterial thromboembolism in cardiac surgical patients raises risk-benefit considerations. Adherence to our institutions' guidelines was poor.

The evidence for the use of recombinant factor VIIa in massive bleeding: revision of the transfusion policy framework

In 2006, the Canadian National Advisory Committee on Blood and Blood Products (NAC) developed a transfusion policy framework for the use of off-label recombinant factor VIIa (rFVIIa) in massive bleeding. Because the number of randomised controlled trials has doubled, the NAC undertook a review of the policy framework in 2011. On the basis of the review of 29 randomised controlled trials, there remains little evidence to support the routine use of rFVIIa in massive bleeding. Mortality benefits have not been demonstrated. Contrarily, an increase in arterial thromboembolic events has been observed with the use of off-label rFVIIa. Given the absence of evidence of benefit and with evidence of the risk of harm, the NAC recommends that recombinant VIIa no longer be used for the off-label indications of prevention and treatment of bleeding in patients without haemophilia.

Recombinant factor VIIa for the prevention and treatment of bleeding in patients without haemophilia

BACKGROUND

Recombinant factor VIIa (rFVIIa) is licensed for use in patients with haemophilia and inhibitory allo-antibodies. It is also increasingly being used for off-license indications to prevent bleeding in operations where blood loss is likely to be high, and/or to stop bleeding that is proving difficult to control by other means.

OBJECTIVES

To assess the effectiveness of rFVIIa when used therapeutically to control active bleeding, or prophylactically to prevent (excessive) bleeding in patients without haemophilia.

SEARCH STRATEGY

We searched the Cochrane Injuries Group Specialised Register, CENTRAL, MEDLINE, EMBASE and other specialised databases up to 25 February 2009.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing rFVIIa with placebo, or one dose of rFVIIa with another, in any patient population (except haemophilia). Outcomes were mortality, blood loss or control of bleeding, red cell transfusion requirements, number of patients transfused and thromboembolic adverse events.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed potentially relevant studies for inclusion, extracted data and examined risk of bias. We considered prophylactic and therapeutic rFVIIa studies separately.

MAIN RESULTS

Twenty-five RCTs were included: 24 were placebo-controlled double-blind RCTs and one compared different doses of rFVIIa.Fourteen trials involving 1137 participants examined the prophylactic use of rFVIIa; 713 received rFVIIa. There was no evidence of mortality benefit (RR 1.06; 95% CI 0.50 to 2.24). There was decreased blood loss (WMD -272 mL; 95% CI -399 to -146) and decreased red cell transfusion requirements (WMD -243 mL; 95% CI -393 to -92) with rFVIIa treatment; however these values were likely overestimated due to the inability to incorporate data from trials showing no difference of rFVIIa treatment compared to placebo. There was a trend in favour of rFVIIa in the number of participants transfused (RR 0.91; 95% CI 0.82 to 1.02). But there was a trend against rFVIIa with respect to thromboembolic adverse events (RR 1.32; 95% CI 0.84 to 2.06).Eleven trials involving 2366 participants examined the therapeutic use of rFVIIa; 1507 received rFVIIa. There were no outcomes where any observed advantage, or disadvantage, of rFVIIa over placebo could not have been observed by chance alone. There was a trend in favour of rFVIIa for reducing mortality (RR 0.89; 95% CI 0.77 to 1.03). However, there was a trend against rFVIIa for increased thromboembolic adverse events (RR 1.21; 95% CI 0.93 to 1.58).

AUTHORS' CONCLUSIONS

The effectiveness of rFVIIa as a more general haemostatic drug, either prophylactically or therapeutically, remains unproven. The use of rFVIIa outside its current licensed indications should be restricted to clinical trials.

Recombinant factor VIIa affects anastomotic patency of vascular grafts in a rabbit model

OBJECTIVE

Recombinant factor VIIa can decrease postoperative bleeding after cardiac surgery. However, the potential for recombinant factor VIIa to cause early vascular graft occlusion at the site of new vascular anastomoses has not been fully explored. We hypothesized that recombinant factor VIIa would cause a dose-dependent reduction in vascular graft patency in rabbits.

METHODS

Reversed end-to-end interpositional vein grafts were sutured into the carotid artery of heparinized rabbits, and then recombinant factor VIIa (300 μg/kg, 90 μg/kg, or 20 μg/kg intravenously) or placebo was administered (n = 16/group). Graft patency was assessed at 24 hours using a vascular ultrasound probe. Factor VII activity levels were measured using a prothrombin time-based assay. In different rabbits, the patency of venous end-to-side anastomoses and simple carotid arterial repairs was assessed (recombinant factor VIIa, 300 μg/kg vs placebo, n = 8/group). Data were analyzed using Fisher's exact test, t tests, or analysis of variance.

RESULTS

Physiologic variables (activated clotting time, hemoglobin, pH, Pao(2)) and vessel diameter were not different between groups. Vein graft patency was reduced (93.8%, 81.2%, 13.8%, and 6.3%) as factor VII activity levels increased (1.8 ± 0.4, 4.4 ± 2.1, 11.8 ± 4.7, and 23.6 ± 16.9 U/mL, respectively) with increasing doses of recombinant factor VIIa administered (0, 20, 90, and 300 μg/kg, respectively, P < .05). Patency in the arterial repairs and end-to-side venous grafts was also reduced in recombinant factor VIIa-treated rabbits (P < .05 for both).

CONCLUSIONS

This study suggests that recombinant factor VIIa is associated with a dose-dependent increase in fresh vascular graft occlusion. Higher doses of recombinant factor VIIa may be associated with increased thrombotic outcomes.

Hemotransfusion in Combat Trauma

The collaboration of blood transfusion service in the management of severely combat-injured individuals has proved to be an essential factor for the successful treatment of these patients. While the operating and anesthesiology teams are engaged in maintaining the vital signs and controlling blood loss of the injured, the transfusion service representatives follow the information on the amount of blood products given and the latest laboratory tests, as well as provide consultations regarding further blood component requirements on the basis of data obtained. A major effort of the treating team should be aimed at diagnosis and correction of coagulopathy, acidosis, and hypothermia. For the massively bleeding combat trauma injured, which can amount to as high as 8% of all trauma patients, a generous use of plasma at a one-to-one ratio with packed cells, along with the early addition of platelets and cryoprecipitates, should be considered. Early point-of-care thromboelastography is helpful for identification of coagulopathies. The use of a preset massive transfusion protocol is beneficial; however, it should be tailored according to the patient’s actual needs, depending on the type of injury and the individual’s general condition.

Correction of coagulation in dilutional coagulopathy: use of kinetic and capacitive coagulation assays to improve hemostasis

The management of dilutional coagulopathy due to fluid infusion and massive blood loss is a topic that deserves a biochemical approach. In this review article, we provide an overview of current guidelines and recommendations on diagnosis and on management of transfusion in acquired coagulopathy. We discuss the biochemical differences between kinetic clotting assays (clotting times) and new capacitive coagulation measurements that provide time-dependent information on thrombin generation and fibrin clot formation. The available evidence suggests that a combination of assay types is required for evaluating new transfusion protocols aimed to optimize hemostasis and stop bleeding. Although there is current consensus on the application of fresh frozen plasma to revert coagulopathy, factor concentrates may appear to be useful in the future.

Massive transfusion: new insights

Massive transfusion (MT) is used for the treatment of uncontrolled hemorrhage. Earlier definitive control of life-threatening hemorrhage has significantly improved patient outcomes, but MT is still required. A number of recent advances in the area of MT have emerged, including the use of "hypotensive" or "delayed" resuscitation for victims of penetrating trauma before hemorrhage is controlled and "hemostatic resuscitation" with increased use of plasma and platelet transfusions in an attempt to maintain coagulation. These advances include the earlier use of hemostatic blood products (plasma, platelets, and cryoprecipitate), recombinant factor VIIa as an adjunct to the treatment of dilutional and consumptive coagulopathy, and a reduction in the use of isotonic crystalloid resuscitation. MT protocols have been developed to simplify and standardize transfusion practices. The authors of recent studies have advocated a 1:1:1 ratio of packed RBCs to fresh frozen plasma to platelet transfusions in patients requiring MT to avoid dilutional and consumptive coagulopathy and thrombocytopenia, and this has been associated with decreased mortality in recent reports from combat and civilian trauma. Earlier assessment of the exact nature of abnormalities in hemostasis has also been advocated to direct specific component and pharmacologic therapy to restore hemostasis, particularly in the determination of ongoing fibrinolysis.

The role of recombinant-activated factor VII in bleeding trauma patients

PURPOSE OF REVIEW

Exsanguinating hemorrhage and postshock organ failure account for 35-40% of deaths from trauma, and there is an increasing recognition of the importance of coagulopathy in the evolution of this disease.

RECENT FINDINGS

Since 1999, case reports, small series, retrospective studies and a few controlled trials have reported the use of recombinant-activated factor VII (rFVIIa) as an adjunct for reversal of coagulopathy in trauma patients, and numerous other publications have examined the use of rFVIIa in related conditions such as traumatic brain injury, hemorrhagic stroke and uncontrolled surgical bleeding.

SUMMARY

We present a brief discussion of the mechanism of action of rFVIIa and its role in facilitating hemostasis and a review of the recent medical literature on the use of rFVIIa in trauma patients, including current guidelines and controversies.

Recombinant factor VIIa for the prevention and treatment of bleeding in patients without haemophilia

BACKGROUND

Recombinant factor VIIa (rFVIIa) is licensed for use in patients with haemophilia and inhibitory allo-antibodies. It is also increasingly being used for off-license indications to prevent bleeding in operations where blood loss is likely to be high, and/or to stop bleeding that is proving difficult to control by other means.

OBJECTIVES

To assess the effectiveness of rFVIIa when used therapeutically to control active bleeding, or prophylactically to prevent (excessive) bleeding in patients without haemophilia.

SEARCH STRATEGY

We searched the Cochrane Injuries Group's Specialised Register, CENTRAL, MEDLINE, EMBASE and other specialised databases up to March 2006. We also searched reference lists of articles and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing rFVIIa with placebo, or one dose of rFVIIa with another, in any patient population with the exception of those with haemophilia. There was no restriction by outcomes examined, but this review focuses on mortality, blood loss or control of bleeding, red cell transfusion requirements, number of patients transfused and thromboembolic adverse events.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed potentially relevant studies for inclusion. Data were extracted and methodological quality was examined. Studies using rFVIIa prophylactically and those using rFVIIa therapeutically have been considered separately. Data were pooled using fixed and random effects models, but random effects models were preferred because of the variability in clinical features of the included studies.

MAIN RESULTS

Thirteen trials met the inclusion criteria; all were placebo-controlled double-blind RCTs. Six trials involving 724 participants examined the prophylactic use of rFVIIa; 379 received rFVIIa. There were no outcomes by which any observed advantage, or disadvantage, of rFVIIa over placebo could not have been observed by chance alone. There were trends in favour of rFVIIa for a number of outcomes, particularly the number of participants transfused, pooled RR 0.85 (95% CI 0.72 to 1.01) but this was balanced by a trend against rFVIIa with respect to thromboembolic adverse events, pooled RR 1.25 (95% CI 0.76 to 2.07). Seven trials involving 1214 participants examined the therapeutic use of rFVIIa; 687 received rFVIIa. There were no outcomes where any observed advantage, or disadvantage, of rFVIIa over placebo could not have been observed by chance alone. There was a trend in favour of rFVIIa for reducing mortality, RR 0.82 (95% CI 0.64 to 1.04), although no other clear trends in favour of rFVIIa were noted for other desired outcomes. Interpretation of these results must take into account one study which could not be included in the quantitative summary but which showed results strongly in favour of rFVIIa for the treatment of intra-cerebral haemorrhage. There was a trend against rFVIIa with respect to thromboembolic adverse events; the RR 1.50 (95% CI 0.86 to 2.62).

AUTHORS' CONCLUSIONS

Although rFVIIa has a role in the management of patients with haemophilia, its effectiveness as a more general haemostatic drug, either prophylactically or therapeutically, remains uncertain. Its effectiveness as a therapeutic agent, particularly for intra-cerebral haemorrhage, looks more encouraging than prophylactic use. The use of rFVIIa outside its current licensed indications should be very limited and its wider use await the results of ongoing and possibly newly commissioned RCTs. In the interim, rFVIIa use should be restricted to clinical trials.