The role of recombinant factor VIIa in on-pump cardiac surgery: Proceedings of the Canadian Consensus Conference

The Use of Factor Eight Inhibitor Bypass Activity (FEIBA) for the Treatment of Perioperative Hemorrhage in Left Ventricular Assist Device Implantation

OBJECTIVE

To test the hypothesis that factor eight inhibitor bypassing activity (FEIBA) can be used to control bleeding following left ventricular assist device (LVAD) implantation without increasing the 14-day composite thrombotic outcome of pump thrombus, ischemic cerebrovascular accidents, pulmonary embolism, and deep venous thrombosis.

DESIGN

Retrospective cohort study.

SETTING

Academic hospital.

PARTICIPANTS

Three hundred nineteen consecutive patients who underwent LVAD implantation (December 1, 2009 to December 30, 2018).

INTERVENTION

FEIBA administered to control perioperative hemorrhage.

MEASUREMENTS AND MAIN RESULTS

The 82 patients (25.7%) in the FEIBA cohort had more risk factors for perioperative hemorrhage, such as lower preoperative platelet count (169 ± 66 v 194 ± 68 × 10³/mL, p = 0.004), prior cardiac surgery (36.6% v 21.9%, p = 0.008), and longer cardiopulmonary bypass (CPB) time (100.3 v 75.2 minutes, p = 0.001) than the 237 controls. After 16.6 units (95% CI: 14.3-18.9) of blood products were given, 992 units (95% CI: 821-1163) of FEIBA were required to control bleeding in the FEIBA cohort. Compared to the controls, there were no differences in the 14-day composite thrombotic outcome (11.0% v 7.6%, p = 0.343) or mortality rate (3.7% v 1.3%, p = 0.179). Multivariate logistical regression identified preoperative international normalized ratio (odds ratio [OR]: 1.30, 95% CI: 1.04-1.62) and CPB time (OR: 1.11, 95% CI: 1.02-1.20) as risk factors for 14-day thrombotic events, but FEIBA usage was not associated with an increased risk.

CONCLUSIONS

In this retrospective cohort study, the use of FEIBA (∼1,000 units, ∼13 units/kg) to control perioperative hemorrhage following LVAD implantation was not associated with increases in mortality or composite thrombotic outcome.

Thrombin generation and bleeding in cardiac surgery: a clinical narrative review

This narrative review discusses the role of thrombin generation in coagulation and bleeding in cardiac surgery, the laboratory methods for clinical detection of impaired thrombin generation, and the available hemostatic interventions that can be used to improve thrombin generation. Coagulopathy after cardiopulmonary bypass (CPB) is associated with excessive blood loss and adverse patient outcomes. Thrombin plays a crucial role in primary hemostasis, and impaired thrombin generation can be an important cause of post-CPB coagulopathy. Existing coagulation assays have significant limitations in assessing thrombin generation, but whole-blood assays designed to measure thrombin generation at the bed-side are under development. Until then, clinicians may need to institute therapy empirically for non-surgical bleeding in the setting of normal coagulation measures. Available therapies for impaired thrombin generation include administration of plasma, prothrombin complex concentrate, and bypassing agents (recombinant activated factor VII and factor eight inhibitor bypassing activity). In vitro experiments have explored the relative potency of these therapies, but clinical studies are lacking. The potential incorporation of thrombin generation assays into clinical practice and treatment algorithms for impaired thrombin generation must await further clinical development.

Case report: Intraoperative thrombosis cardiac arrest in extended right hepatectomy involving use of local haemostatic agent in intraoperative cell salvage (ICS) and administration of recombinant activated factor VII (rFVIIa)

•

Intractable intraoperative haemorrhage is a result of both surgical and coagulopathic (nonsurgical) components.

•

There is increasing off-label use of rFVIIa for ceasing refractory bleeding aside from its application in patient with haemophilia.

•

rFVIIa use may be associated with increased thromboembolic events according to some literature.

•

The use of topical haemostatic agent in conjunction with ICS may potentially lead to systemic clot formation upon re-infusion of the chemical.

•

Avoid use of cell saver suction while the surgical field is contaminated with topical clotting factors before irrigation with 0.9% sodium chloride.

Introduction

In modern surgical era, local haemostatic agents and blood components such as recombinant activated factor VII (rFVIIa) have expanded surgeons’ armamentarium in controlling “surgical” and “nonsurgical bleeding”. We report a case of intraoperative thrombosis and cardiac arrest involving use of local haemostatic agent in intraoperative cell salvage and rFVIIa administration in extended right hepatectomy.

Presentation of case

A 46-year-old lady underwent extended right hepatectomy using cardiopulmonary bypass (CPB) and autotransfusion with ICS for metastatic gastrointestinal stromal tumour. She became extremely coagulopathic following weaning of CPB despite an array of fluid and blood products replacements. Decision to administer rFVIIa as a measure to arrest bleeding was unsuccessful. Extensive systemic thrombosis occurred which resulted in cardiac arrest and mortality.

Discussion

The thromboembolic event was unclear but likely multifactorial. Two important hypotheses were the administration of rFVIIa and use of local haemostatic agent in ICS.

Conclusion

Reported incidence of thromboembolism with use of rFVIIa in refractory bleeding is variable. More randomised controlled trials are needed to ascertain the efficacy and safety profile of the haemostatic agent. At present, off-label use of rFVIIa should be guided by the risk:benefit profile on a case-to-case basis. The authors also feel strongly against the use of local haemostatic gel in conjunction with ICS due to potential systemic circulation of the thrombin.

Vascular Injury and Thrombotic Potential: A Note of Caution About Recombinant Factor VIIa

Postoperative hemorrhage following cardiac surgery increases morbidity, mortality, and costs. Several case reports have described the successful use of recombinant factor VIIa to decrease or stop bleeding in patients undergoing cardiac surgery. The mechanism of action of recombinant factor VIIa is thought to be increased site-specific thrombin generation by tissue factor—mediated activation of coagulation or from activated platelets. However, there have also been many reports of thrombotic complications after recombinant factor VIIa administration. Randomized clinical trials and further laboratory studies should help better clarify the efficacy, safety, cost-effectiveness, and optimal dosing of recombinant factor VIIa in the cardiac surgical setting.

Recombinant Activated Factor VII Significantly Reduces Transfusion Requirements in Cardiothoracic Surgery

Background

The off-label use of recombinant activated factor VII (rFVIIa) for intractable bleeding is associated with a risk of thrombotic events. The objective of this study was to evaluate the incidence and predictors of rFVIIa-related thrombotic events and its efficacy in the reduction of transfusion requirements during various surgeries.

Methods

Ninety-two cases received rFVIIa for uncontrollable bleeding despite medical and surgical hemostasis. The incidence and risk factors of thrombotic events were analyzed. Blood products transfused in the 24 h before and after rFVIIa injection were calculated. Subgroup analysis was performed to see which types of surgeries benefited most from rFVIIa.

Results

The main indication for rFVIIa administration was uncontrollable bleeding during cardiothoracic surgery followed by coagulopathy due to liver failure followed by neurosurgical procedures. Requirements of blood products after rFVIIa decreased significantly by 45 % (p = 0.012), 52 % (p = 0.0001), and 75 % (p = 0.0001) for red blood cells, plasma, and cryoprecipitate, respectively. Subgroup analysis showed that cardiothoracic surgery was the sole group that benefited from rFVIIa with a reduction in transfusion of red blood cells (p = 0.013), plasma (p = 0.0001), and cryoprecipitate (p = 0.0001). Thrombotic events occurred in 9.8 % of the cases mostly on the arterial side (89 %) and have not contributed to mortality.

Conclusion

rFVIIa can significantly reduce transfusion requirements when given for intractable bleeding during cardiothoracic surgery at the expense of thrombotic events in approximately one tenth of the cases. Further prospective studies are necessary to study if this effect of rFVIIa is translated to a favorable outcome.

Electronic supplementary material

The online version of this article (doi:10.1007/s40268-015-0093-9) contains supplementary material, which is available to authorized users.

Evaluation of a novel transfusion algorithm employing point-of-care coagulation assays in cardiac surgery: a retrospective cohort study with interrupted time-series analysis

BACKGROUND

Cardiac surgery requiring the use of cardiopulmonary bypass is frequently complicated by coagulopathic bleeding that, largely due to the shortcomings of conventional coagulation tests, is difficult to manage. This study evaluated a novel transfusion algorithm that uses point-of-care coagulation testing.

METHODS

Consecutive patients who underwent cardiac surgery with bypass at one hospital before (January 1, 2012 to January 6, 2013) and after (January 7, 2013 to December 13, 2013) institution of an algorithm that used the results of point-of-care testing (ROTEM; Tem International GmBH, Munich, Germany; Plateletworks; Helena Laboratories, Beaumont, TX) during bypass to guide management of coagulopathy were included. Pre- and postalgorithm outcomes were compared using interrupted time-series analysis to control for secular time trends and other confounders.

RESULTS

Pre- and postalgorithm groups included 1,311 and 1,170 patients, respectively. Transfusion rates for all blood products (except for cryoprecipitate, which did not change) were decreased after algorithm institution. After controlling for secular pre- and postalgorithm time trends and potential confounders, the posttransfusion odds ratios (95% CIs) for erythrocytes, platelets, and plasma were 0.50 (0.32 to 0.77), 0.22 (0.13 to 0.37), and 0.20 (0.12 to 0.34), respectively. There were no indications that the algorithm worsened any of the measured processes of care or outcomes.

CONCLUSIONS

Institution of a transfusion algorithm based on point-of-care testing was associated with reduced transfusions. This suggests that the algorithm could improve the management of the many patients who develop coagulopathic bleeding after cardiac surgery. The generalizability of the findings needs to be confirmed.

The Effect of Intravenous Administration of Active Recombinant Factor VII on Postoperative Bleeding in Cardiac Valve Reoperations; A Randomized Clinical Trial

BACKGROUND

Postoperative bleeding after cardiac reoperations is among the most complicating problems, both for the physicians and for the patients. Many modalities have been used to decrease its adverse effects and the need for blood products administration.

OBJECTIVES

In a randomized double-blinded clinical trial of redo cardiac valve surgery in adult, the effect of active recombinant factor VII (rFVIIa) on postoperative bleeding was compared with placebo. Chest tube drainage was used for comparison of bleeding between the two groups.

PATIENTS AND METHODS

Two groups of 18 patients undergoing redo valve surgeries were treated and compared regarding chest tube drainage, need for blood products, prothrombin time (PT), partial thromboplastin time (PTT), hemoglobin and hematocrit, platelet count, and international normalized ratio (INR) in first 24 hours after surgery. Bleeding was assessed at 3rd, 12th, and 24th hour after operation. In rFVIIa group, 40 µg/kg of AryoSeven was administered before end of surgery and same volume of normal saline was administered as placebo in the control group.

RESULTS

Study groups showed no difference regarding baseline variables. Three patients in rFVIIa group (16.67%) and 13 in placebo group (72.23%) received blood products (P < 0.01). Chest tube blood drainage at 24th hour after operation was 315 ± 177 mL in rFVIIa group and 557 ± 168 mL in control group (P = 0.03). At third and 12th hour after operation, the difference was not statistically significant (P = 0.71 and P = 0.22, respectively). Postoperative ICU stay was not different; while extubation was longer in the placebo group (352 ± 57 vs. 287 ± 46 minutes; P = 0.003).

CONCLUSIONS

Our study demonstrated the efficacy of rFVIIa in controlling postoperative bleeding in redo cardiac valve surgeries regarding subsequent blood loss and transfusion requirement; however, outcome results remains to be defined.

Systematic review: benefits and harms of in-hospital use of recombinant factor VIIa for off-label indications

BACKGROUND

Recombinant factor VIIa (rFVIIa), a hemostatic agent approved for hemophilia, is increasingly used for off-label indications.

PURPOSE

To evaluate the benefits and harms of rFVIIa use for 5 off-label, in-hospital indications: intracranial hemorrhage, cardiac surgery, trauma, liver transplantation, and prostatectomy.

DATA SOURCES

Ten databases (including PubMed, EMBASE, and the Cochrane Library) queried from inception through December 2010. Articles published in English were analyzed.

STUDY SELECTION

Two reviewers independently screened titles and abstracts to identify clinical use of rFVIIa for the selected indications and identified all randomized, controlled trials (RCTs) and observational studies for full-text review.

DATA EXTRACTION

Two reviewers independently assessed study characteristics and rated study quality and indication-wide strength of evidence.

DATA SYNTHESIS

16 RCTs, 26 comparative observational studies, and 22 noncomparative observational studies met inclusion criteria. Identified comparators were limited to placebo (RCTs) or usual care (observational studies). For intracranial hemorrhage, mortality was not improved with rFVIIa use across a range of doses. Arterial thromboembolism was increased with medium-dose rFVIIa use (risk difference [RD], 0.03 [95% CI, 0.01 to 0.06]) and high-dose rFVIIa use (RD, 0.06 [CI, 0.01 to 0.11]). For adult cardiac surgery, there was no mortality difference, but there was an increased risk for thromboembolism (RD, 0.05 [CI, 0.01 to 0.10]) with rFVIIa. For body trauma, there were no differences in mortality or thromboembolism, but there was a reduced risk for the acute respiratory distress syndrome (RD, -0.05 [CI, -0.02 to -0.08]). Mortality was higher in observational studies than in RCTs.

LIMITATIONS

The amount and strength of evidence were low for most outcomes and indications. Publication bias could not be excluded.

CONCLUSION

Limited available evidence for 5 off-label indications suggests no mortality reduction with rFVIIa use. For some indications, it increases thromboembolism.

Recombinant factor VIIa (NovoSeven RT) use in high risk cardiac surgery

OBJECTIVE

The use of recombinant factor VIIa (rFVIIa) (NovoSeven RT(®)) to establish hemostasis during massive perioperative bleeding in cardiac surgery has been explored in several retrospective studies. While early results are promising, a paucity of data leaves many questions about its safety profile. We sought to further define its use and associated outcomes in a large cohort study at a single institution.

METHODS

A retrospective cohort study design was used, in which 236 patients received rFVIIa for bleeding after cardiac surgery. These patients were matched with a cohort of 213 subjects, who had similar operations during the same period of time. Primary end points included thrombo-embolic events, mortality, incidence of re-operation, use of blood products, and patient disposition at 30 days. Statistical significance was assessed at p < 0.05.

RESULTS

There was no statistically significant difference in the incidence of stroke (3.4%, 1.9%; p = 0.32), renal failure (8.5%, 7.0%; p = 0.57), or 30-day mortality (7.7%, 4.3%; p = 0.14) between the rFVIIa and the control groups, respectively. The rFVIIa group did experience a higher rate of re-operation for bleeding (11.0%, 1.9%; p = 0.0001) and had a two-fold increase in the use of each of the following: cryoprecipitate, fresh-frozen plasma, platelets, and packed red blood cells, relative to the control group (p < 0.00001).

CONCLUSIONS

rFVIIa is an effective hemostatic agent for intractable bleeding in high-risk cardiac surgery with an acceptable safety profile. rFVIIa does not appear to be associated with increased postoperative complications, including thrombo-embolic events and death.

Systematic review: benefits and harms of in-hospital use of recombinant factor VIIa for off-label indications

BACKGROUND

Recombinant factor VIIa (rFVIIa), a hemostatic agent approved for hemophilia, is increasingly used for off-label indications.

PURPOSE

To evaluate the benefits and harms of rFVIIa use for 5 off-label, in-hospital indications: intracranial hemorrhage, cardiac surgery, trauma, liver transplantation, and prostatectomy.

DATA SOURCES

Ten databases (including PubMed, EMBASE, and the Cochrane Library) queried from inception through December 2010. Articles published in English were analyzed.

STUDY SELECTION

Two reviewers independently screened titles and abstracts to identify clinical use of rFVIIa for the selected indications and identified all randomized, controlled trials (RCTs) and observational studies for full-text review.

DATA EXTRACTION

Two reviewers independently assessed study characteristics and rated study quality and indication-wide strength of evidence.

DATA SYNTHESIS

16 RCTs, 26 comparative observational studies, and 22 noncomparative observational studies met inclusion criteria. Identified comparators were limited to placebo (RCTs) or usual care (observational studies). For intracranial hemorrhage, mortality was not improved with rFVIIa use across a range of doses. Arterial thromboembolism was increased with medium-dose rFVIIa use (risk difference [RD], 0.03 [95% CI, 0.01 to 0.06]) and high-dose rFVIIa use (RD, 0.06 [CI, 0.01 to 0.11]). For adult cardiac surgery, there was no mortality difference, but there was an increased risk for thromboembolism (RD, 0.05 [CI, 0.01 to 0.10]) with rFVIIa. For body trauma, there were no differences in mortality or thromboembolism, but there was a reduced risk for the acute respiratory distress syndrome (RD, -0.05 [CI, -0.02 to -0.08]). Mortality was higher in observational studies than in RCTs.

LIMITATIONS

The amount and strength of evidence were low for most outcomes and indications. Publication bias could not be excluded.

CONCLUSION

Limited available evidence for 5 off-label indications suggests no mortality reduction with rFVIIa use. For some indications, it increases thromboembolism.

Administration of recombinant activated factor VII in the intensive care unit after complex cardiovascular surgery: clinical and economic outcomes

OBJECTIVE

Refractory bleeding after complex cardiovascular surgery often leads to increased length of stay, cost, morbidity, and mortality. Recombinant activated factor VII administered in the intensive care unit can reduce bleeding, transfusion, and surgical re-exploration. We retrospectively compared factor VII administration in the intensive care unit with reoperation for refractory bleeding after complex cardiovascular surgery.

METHODS

From 1501 patients who underwent cardiovascular procedures between December 2003 and September 2007, 415 high-risk patients were identified. From this cohort, 24 patients were divided into 2 groups based on whether they either received factor VII in the intensive care unit (n = 12) or underwent reoperation (n = 12) for refractory bleeding. Preoperative and postoperative data were collected to compare efficacy, safety, and economic outcomes.

RESULTS

In-hospital survival for both groups was 100%. Factor VII was comparable with reoperation in achieving hemostasis, with both groups demonstrating decreases in chest tube output and need for blood products. Freedom from reoperation was achieved in 75% of patients receiving factor VII, whereas reoperation was effective in achieving hemostasis alone in 83.3% of patients. Prothrombin time, international normalized ratio, and median operating room time were significantly less (P < .05) in patients who received factor VII. Both groups had no statistically significant differences in other efficacy, safety, or economic outcomes.

CONCLUSIONS

Factor VII administration in the intensive care unit appears comparable with reoperation for refractory bleeding after complex cardiovascular surgical procedures and might represent an alternative to reoperation in selected patients. Future prospective, randomized controlled trials might further define its role.

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.

The safety of recombinant factor VIIa in cardiac surgery

We investigated whether there was an association between recombinant activated factor VII (rFVIIa) use in cardiac surgery and thromboembolic events by comparing cases in two medical registries. The incidence of thromboembolic events in patients undergoing cardiac surgery (except isolated coronary artery bypass grafts) who had received rFVIIa and were entered into the Australian and New Zealand Haemostasis Registry was compared with the background incidence in patients entered in the Australasian Society for Cardiac and Thoracic Surgeons database. Mortality, length of hospital stay and thromboembolic complications such as stroke, perioperative myocardial infarction and pulmonary embolism data were analysed. A total of 705 patients in the Registry were compared with 6554 patients in the Thoracic Surgeons database. The use of rFVIIa was independently associated with higher mortality (odds ratio 2.55, P < 0.001) and longer hospital stay (odds ratio 1.54, P = 0.020). However multiple regression analyses showed no independent association between rFVIIa and stroke (odds ratio 1.0, P = 0.994) or perioperative myocardial infarction (odds ratio 0.29, P = 0.053), while the use of rFVIIa was associated with fewer pulmonary emboli (odds ratio 0.02, P < 0.001). These findings indicate that patients who received rFVIIa had increased mortality and length of hospital stay, as expected, but that rFVIIa use was not associated with an increased incidence of stroke or perioperative myocardial infarction. In the absence of randomised controlled clinical trials, this analysis suggests that the off-label use of rFVIIa in cardiac surgery does not significantly increase thromboembolic events.

Recombinant activated factor VII in controlling bleeding in non-hemophiliac patients

BACKGROUND

There have been recent reports on the successful use of recombinant factor VIIa (rFVIIa) in non-hemophiliac patients who have experienced heavy blood loss due to trauma with extensive organ damage and who have received multiple blood transfusions with hemostatic changes without success. The timing of administration, dosage, mortality, units of blood transfusion saved, risk of thrombotic events, and the risk/benefit ratio are still poorly defined.

PATIENTS AND METHODS

We conducted a retrospective review of all medical records of patients who received rFVIIa between January 2003 and March 2008. Data collection included demographic characteristics, diagnosis, indications, comorbidities, and amount of blood products used with rFVIIa, dose of rFVIIa, mortality, and adverse events.

RESULTS

We identified 45 patients, 27 (60%) males and 18 (40%) females, with a median age of 52 years. The median dose of rFVIIa was 40 microg/kg (range, 20-120 microg/kg). Five (11.1%) patients needed a second dose of rFVIIa (dose range of 20-85 microg/kg) whereas three patients (6.7%) needed a third dose of rFVIIa (dose range of 40-60 microg/kg). There was a marked and significant reduction in transfusion requirements for packed red blood cells (P=.0078). Overall transfusion requirements significantly decreased after the infusion of rFVIIa (P=.0323). Nineteen patients (42.2%) died and thrombosis was documented in 3 patients (6.7%).

CONCLUSION

Use of rFVIIa should be based on sound clinical evidence to balance the risks, benefits, and cost if used among non-hemophiliacs. Prospective randomized studies are needed to investigate the efficacy and cost-effectiveness of rFVIIa for this indication and to allow a final assessment of the importance of this treatment.

[Successful use of recombinant factor VIIa in the control of a massive bleeding in two patients with biventricular assist device (Thoratec)]

Massive bleeding is a dreaded complication of biventricular mechanical assistance implantation. Its origin is multifactorial. Blood products transfusion associated with correction of coagulopathy are sometimes insufficient. We report two cases of massive bleeding after a Thoratec biventricular assistance implantation. After surgical haemostasis failure and despite the correction of coagulation disorders, a major bleeding persisted, so these patients received a single injection of 90 microg/kg of rFVIIa. This allowed in both cases a significant reduction of the bleeding and the restoration of normal haemodynamic conditions. This treatment was not complicated by any thrombotic accident.

Scientific and logistical challenges in designing the CONTROL trial: recombinant factor VIIa in severe trauma patients with refractory bleeding

BACKGROUND

Clinical research in trauma patients poses multiple challenges in study design. These reflect the heterogeneity of injury and treatment, the paucity of acceptable study endpoints aside from mortality, and the difficulties inherent in obtaining informed consent in acutely ill populations. A current example of this problem is the study of recombinant factor VIIa (rFVIIa), which has attracted considerable interest as a systemic procoagulant agent for use in trauma patients with exsanguinating hemorrhage.

PURPOSE

To report on the implementation of an international trial - CONTROL - intended to assess the efficacy and safety of rFVIIa in trauma, and discuss trauma research study design in light of this experience.

METHODS

The CONTROL trial international steering committee confronted a number of barriers in the design of the CONTROL trial. They addressed methodologies for (1) standardizing entry criteria for trauma patients suffering inherently heterogeneous injuries, (2) obtaining informed consent in an acutely injured population with altered levels of consciousness, (3) avoiding futile care, while recruiting subjects with incompletely diagnosed injuries, (4) standardizing trauma intensive care across different investigating sites and countries, and (5) establishing study endpoints that were both clinically relevant and convincing to regulatory authorities. The resulting study methodology is reported.

RESULTS

The CONTROL trial began active recruitment in October 2005, and was halted on June 11, 2008 because the observed mortality in the 576 enrolled patients was so far below expectations that the study would lack sufficient statistical power at the planned number of subjects to demonstrate a benefit. The utility of the endpoints selected for study will not be known until completion of data analysis.

LIMITATIONS

Any clinical trial in trauma patients must cope with the urgency of care required, issues of patient heterogeneity, standardization of care across multiple centers, and the difficulties of obtaining informed consent.

CONCLUSION

Research in acutely hemorrhaging trauma patients presents numerous scientific and ethical challenges. The methodology of the CONTROL study is presented as an example of how some of these challenges can be approached and managed, and of the pitfalls that may arise.

Effect of Recombinant Activated Factor VII in Critical Bleeding: Clinical Experience of a Single Center

Recombinant activated factor VII (rFVIIa) has been successfully used ‘‘off-label’’ in patients with refractory life-threatening hemorrhage. Intravenous rFVIIa was given to 31 patients unresponsive to standard therapy with blood products and surgical reexploration, who were bleeding due to trauma, surgery, organ transplantation, liver cirrhosis, ruptured uterus. We recorded their coagulation and hematologic profiles, acid-base balance, blood loss, number of red blood cells (RBC), plasma and platelet transfusions, complications, and survival. rFVIIa (mean dose 132.2 ± 56.3 μg/kg) effectively contained the hemorrhage in 28/31 (90.3%) cases, with a mean reduction in blood loss from 12.4 ± 10.2 to 2.7 ± 2.2 L (P < .0001). The need for RBC, platelet, and plasma transfusion decreased significantly after rFVIIa, with a consequent significant improvement in clotting of test hematocrit, pH, and bicarbonates. Four patients had adverse events potentially related to rFVIIa. The survival rates after 1 and 30 days were 48.4% and 29.1%, respectively.

Further understanding of recombinant activated factor VII mode of action

Recombinant activated factor VII (rFVIIa) is being increasingly used to treat bleeding associated with a variety of non-hemophilic coagulopathic indications, and its mechanism of action in these areas is under active investigation. Numerous studies have shown that FVIIa binds with low affinity to activated platelets; rFVIIa can subsequently enhance platelet-surface thrombin generation by activating factor (F) X and by contributing additional FIXa to the hemostatic process. This FIXa can rapidly activate additional FX, which may explain why non-hemophilic coagulopathic bleeds respond to lower doses of rFVIIa than do hemophilic bleeds. However, the platelet surface may be able to process only a limited amount of FXa, accounting for the observation that some models of non-hemophilic coagulopathy show a plateau in the effect of rFVIIa.