Recombinant Activated Factor VII in Cardiac Surgery: A Systematic Review

Aprotinin use during cardiac surgery: recent alterations and effects on blood product utilization

OBJECTIVE

To investigate a single institution's changing use of aprotinin and subsequent effects on intraoperative blood product utilization (red blood cells/fresh frozen plasma) and postoperative clinical bleeding requiring reoperation.

DESIGN

Retrospective study.

SETTING

Single university institution (University of Chicago).

MEASUREMENTS

Data from 499 adult patients undergoing cardiac surgery requiring cardiopulmonary bypass (CPB) over a two-year period (February 2005 - January 2007) were reviewed. The first 12 months (Feb 2005 - Jan 2006, Group 2005-2006) of data were compared with that from the second 12-month period (Feb 2006 - Jan 2007, Group 2006-2007). Information regarding patient demographics, surgical procedures, aprotinin use (none, half-dose, full-dose), and blood product use during CPB was retrospectively retrieved and analyzed.

MAIN RESULTS

When Group 2006-2007 data was compared with that from Group 2005-2006, full-dose aprotinin use had significantly decreased (58% to 17%, P < 0.001), non-use of aprotinin significantly increased (18% to 47%, P < 0.001), while fresh frozen plasma (FFP) utilization during CPB significantly increased (24% to 36%, P = 0.004). Red blood cell (RBC) transfusion rates remained stable (67% - 69%) yet rates of RBC and FFP transfusion during CPB significantly increased (23% to 34%, P = 0.003). There was also a trend toward increased unplanned reoperations for excessive clinical bleeding (0 pts in Group 2005-2006, three pts in Group 2006-2007).

CONCLUSIONS

As the institution's use of high-dose aprotinin has significantly decreased, the number of patients requiring FFP and FFP/RBC combinations during CPB has significantly increased. Furthermore, a trend toward increasing incidence of unplanned reoperations for excessive clinical bleeding was noted.

[Efficacy of recombinant activated factor VII for massive bleeding after cardiac surgery: experience with 32 patients]

OBJECTIVE

To determine the efficacy of recombinant activated factor VII (rFVIIa) to treat massive bleeding refractory to conventional treatment following cardiac surgery.

PATIENTS AND METHODS

Retrospective study of 32 adults who underwent cardiac surgery and received rFVIIa to treat life-threatening postoperative bleeding after conventional means of correcting coagulopathy had failed.

RESULTS

After administration of rFVIIa (90 microg x kg(-1), coagulation parameters soon became normal and blood loss decreased, with drainage going from a mean (SD) of 463 (321) mL in the hour when rFVIIa was infused to 155 (101) mL in the next hour (P < .001). Blood loss decreased by between 22% and 90% (mean, 66%), and the reduction was over 75% in 45% of the patients. Decreases in the transfusion of packed red blood cells (from 7A.4 [4.1] units to 2.7 [ 2.9] units; P < .001), plasma (from 4.7 [2.9] units to 1.6 [2.0] units; P < .001), and platelets were also noted. Mortality was 25%, although only 1 patient died from hemorrhagic shock. One patient developed thromboembolic complications (ischemic stroke).

CONCLUSION

rFVIIa was effective in treating refractory bleeding after cardiac surgery, reducing blood loss and transfusion requirements and restoring blood parameters to normal.

[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.

Use of rFVIIa for critical bleeding in cardiac surgery: dose variation and patient outcomes

BACKGROUND AND OBJECTIVES

Recombinant activated factor VIIa (rFVIIa) is increasingly being used in non-haemophiliac patients for the treatment of severe bleeding refractory to standard interventions. Optimal dosing regimens remain debated in cardiac surgery. Therefore, this study investigated the use of different rFVIIa dosing practices on response to bleeding and patient outcomes in cardiac surgery patients using data from the Haemostasis Registry.

METHODS

Data were extracted from the Haemostasis Registry that records cases of off-licence rFVIIa use in participating institutions. Univariate analyses compared patients receiving < or =40 microg/kg, 41-60 microg/kg, 61-80 microg/kg, 81-100 microg/kg and >100 microg/kg of rFVIIa on key parameters. Logistic regression models investigated the relationship between independent variables and 28-day mortality.

RESULTS

Complete data was available on 804 cardiac surgery patients who received rFVIIa. Of these, 42 (5.2%) were treated with doses < or =40 microg/kg, while the dose group containing the most patients was 81-100 microg/kg (368, 45.77%). Results demonstrated no significant differences in the rate of thromboembolic adverse events, response to bleeding or 28-day mortality.

CONCLUSIONS

These findings raise the important question of whether lower doses of rFVIIa may be as effective as higher doses in the treatment of severe bleeding in cardiac surgery patients.

Defining the role of recombinant activated factor VII in pediatric cardiac surgery: where should we go from here?

OBJECTIVES

Postoperative hemorrhage is a recognized complication of pediatric cardiac surgery. Both the immature coagulation system and increased susceptibility to hemodilution increase the likelihood of pediatric patients developing coagulopathy when compared with adult counterparts. Treatment options remain limited. Recombinant factor VII (rFVIIa) is a hemostatic agent increasingly used to reduce hemorrhage in other surgical settings, the role of which is unclear in this population. This article systematically reviews the published literature on the use of rFVIIa in pediatric cardiac surgery.

DATA SOURCES AND STUDY SELECTION

A systematic literature search identified reports of rFVIIa administration in pediatric patients undergoing cardiac surgery. Where possible, individual patient-specific data were extracted and pooled statistical analysis was performed.

DATA EXTRACTION AND SYNTHESIS

Twenty-nine articles reporting on the administration of rFVIIa to 169 patients were identified. rFVIIa has been administered to patients with predefined congenital abnormalities of hemostasis to arrest hemorrhage refractory to other interventions and prophylactically in the hope of reducing blood loss. Treatment regimens vary widely, in terms of both first and cumulative dose. Data on chest tube blood loss and two markers of coagulation were pooled and analyzed, and significant improvements were demonstrated. Mortality was 4.4% for the entire cohort but 20% of patients on extracorporeal membrane oxygenation suffered significant thromboembolic complications.

CONCLUSIONS

rFVIIa has an increasingly accepted role in the management of patients with congenital coagulopathies undergoing major surgery. However, randomized trials are required to define the role of rFVIIa as an adjunct to control major hemorrhage in the pediatric cardiac surgical population. Any future work must focus not only on benefits but also on patient safety, particularly, risk of morbid thromboembolic complication.

Safety and Efficacy of Recombinant Activated Factor VII

Background— Blood loss is a common complication of cardiac surgery. Evidence suggests that recombinant activated factor VII (rFVIIa) can decrease intractable bleeding in patients after cardiac surgery. Our objective was to investigate the safety and possible benefits of rFVIIa in patients who bleed after cardiac surgery.

Methods and Results— In this phase II dose-escalation study, patients who had undergone cardiac surgery and were bleeding were randomized to receive placebo (n=68), 40 μg/kg rFVIIa (n=35), or 80 μg/kg rFVIIa (n=69). The primary end points were the number of patients suffering critical serious adverse events. Secondary end points included rates of reoperation, amount of blood loss, and transfusion of allogeneic blood. There were more critical serious adverse events in the rFVIIa groups. These differences did not reach statistical significance (placebo, 7%; 40 μg/kg, 14%; P =0.25; 80 μg/kg, 12%; P =0.43). After randomization, significantly fewer patients in the rFVIIa group underwent a reoperation as a result of bleeding ( P =0.03) or required allogeneic transfusions ( P =0.01).

Conclusions— On the basis of this preliminary evidence, rFVIIa may be beneficial for treating bleeding after cardiac surgery, but caution should be applied and further clinical trials are required because there is an increase in the number of critical serious adverse events, including stroke, in those patients randomized to receive rFVIIa.

Prediction and management of bleeding in cardiac surgery

Excessive bleeding after cardiac surgery can result in increased morbidity and mortality related to transfusion- and hypoperfusion-related injuries to critical organ systems. Our objective was to review mechanisms that result in bleeding after cardiac surgery as well as current and emerging interventions to reduce bleeding and transfusion. We discovered that of point-of-care (POC) tests of hemostatic function can facilitate the optimal management of excessive bleeding and reduce transfusion by facilitating administration of specific pharmacologic or transfusion-based therapy and by allowing physicians to better differentiate between microvascular bleeding and surgical bleeding. Emerging interventions like recombinant FVIIa have the potential to reduce bleeding and transfusion-related sequelae and may be life-saving; however, randomized, controlled trials are needed to confirm safety before they can be used as either first-line therapies for bleeding or bleeding prophylaxis. In conclusion, careful investigation of the role of new interventions is essential as the ability to reduce use of blood products, to decrease operative time and/or re-exploration rates has important implications for overall patient safety and health care costs.

Failure of recombinant factor VIIa to correct the coagulopathy in a case of severe postpartum hemorrhage

BACKGROUND

Postpartum hemorrhage (PPH)remains an important cause of maternal morbidity and mortality. Several published reports suggest that recombinant factor VIIa (rFVIIa) is effective in controlling bleeding in PPH. This study reports a case of severe PPH complicated by disseminated intravascular coagulation(DIC), in which early rFVIIa (44 mg/kg) administration not only failed to control the bleeding in vivo but also, surprisingly, failed to correct the patient's international normalized ratio (INR) in vitro. It was hypothesized that the failure of rFVIIa to correct the INR indicated a deficiency in a downstream coagulation factor(s). To investigate this, coagulation factor levels were measured in blood samples that had been drawn periodically during resuscitation in the operating room.

STUDY DESIGN AND METHODS

Clinical and laboratory data were extracted from the medical record.Plasma samples that had been obtained during resuscitation were frozen, and activity levels of the following factors were subsequently measured: fibrinogen, FII, FV, FVII, F IX, and FX.

RESULTS

After rFVIIa administration, the patient's INR remained elevated at 1.9, and bleeding continued. It was determined that at the time rFVIIa was administered, the patient's fibrinogen level was very low(60 mg/dL). INR normalization and control of bleeding was achieved only after the patient's fibrinogen level was restored to normal. FII, F IX, and FX remained at hemostatic levels throughout resuscitation.

CONCLUSIONS

In this case of severe PPH complicated by DIC, fibrinogen appears to have been limiting at the time rFVIIa was administered. It is suggested that fibrinogen levels should be corrected during PPH resuscitation before rFVIIa use is considered.

Pediatric off-label use of recombinant factor VIIa

OBJECTIVE

Our goal was to report our institutional experience with recombinant factor VIIa for the treatment and/or prevention of bleeding in nonhemophiliac children.

METHODS

This was a retrospective case series in a tertiary pediatric referral hospital.

RESULTS

During 1999-2006, 135 patients received recombinant factor VIIa for off-label use. The median number of doses was 2; the median dose was 88 mug/kg. The most common diagnoses among patients receiving recombinant factor VIIa were disseminated intravascular coagulation/sepsis (28), surgical bleeding (19), procedural prophylaxis (16), and trauma (15). The median volume of blood products administered 24 hours before recombinant factor VIIa treatment was 29.7 vs 11.7 mL/kg 24 hours after treatment. Only 1 high-risk patient had significant bleeding after receiving prophylactic recombinant factor VIIa before an invasive procedure. Nonsurvivors had significantly increased incidence of multiple organ dysfunction syndrome (75%) compared with survivors (23%). The largest group of patients (n = 28) received recombinant factor VIIa for bleeding and/or coagulopathy because of disseminated intravascular coagulation; the mortality in this group was 26 (93%) of 28. Eleven patients received multiple doses of recombinant factor VIIa to treat bleeding complications after hematopoietic stem cell transplant, without improvement in blood use. Mortality in medical patients was 58% vs 16% in surgical patients. Three patients had significant thrombotic adverse events after receiving recombinant factor VIIa, resulting in 2 deaths and 1 leg amputation.

CONCLUSIONS

Off-label use of recombinant factor VIIa significantly decreases blood-product administration; surgical patients had control of life-threatening bleeding with low associated mortality. Prophylactic recombinant factor VIIa may be effective in preventing bleeding if given before invasive procedures in children at high risk. Prolonged use of recombinant factor VIIa for bleeding complications after hematopoietic stem cell transplant is not effective in preventing packed red blood cell transfusion. Presence of disseminated intravascular coagulation and mulitorgan dysfunction syndrome may help predict futility of recombinant factor VIIa treatment. Off-label use of recombinant factor VIIa is associated with thromboembolic events in children.

Recombinant factor VIIa treatment of severe bleeding in cardiac surgery patients: a retrospective analysis of dosing, efficacy, and safety outcomes

OBJECTIVE

To describe rFVIIa dosing and clinical outcomes in cardiovascular surgery patients with refractory bleeding.

DESIGN

Retrospective chart review of patients receiving rFVIIa from January 1, 2004 to September 30, 2005, in the cardiovascular surgery setting.

SETTING

Tertiary care, private teaching hospital.

PARTICIPANTS

Ninety-three patients who received rFVIIa after cardiovascular surgery for the management of refractory bleeding.

INTERVENTIONS

None.

MEASURES AND MAIN RESULTS

Patients received an average of 7.6 +/- 6.8 units of red blood cells (RBCs) before rFVIIa dosing (mean dose, 56.2 +/- 26.5 microg/kg). Median and 25th and 75th quartile blood product consumption was significantly reduced 6 hours after rFVIIa versus 6 hours before (RBCs, -3 units, [-1, -7]; cryoprecipitate, -7.5 units [0, -20]; platelet, -3 units [-1, -4]; fresh frozen plasma, -4 units [-2, -7]). Repeated rFVIIa dosing occurred in 10% of patients, with 8 (8.6%) and 2 (2.25%) patients receiving second and third doses, respectively. Subgroup analysis of each rFVIIa dosing quartile >30 microg/kg showed a significant reduction in RBCs; however, no significant differences were found in the magnitude of RBC reduction or percent of patients requiring massive transfusion among the quartiles. No adverse thrombotic episodes were noted, and the observed mortality (22.6%) was not attributed to rFVIIa therapy.

CONCLUSIONS

rFVIIa effectively reduces blood product use in cardiovascular surgery patients having massive blood loss. Although the optimal dose of rFVIIa for use in cardiovascular surgery remains undetermined, these data provide evidence that dosing regimens using <90 microg/kg are effective in this population and may provide guidance for centers establishing standardized protocols for rFVIIa use in cardiovascular surgery patients.

On-label versus off-label use of recombinant activated factor VII: a comprehensive review of use in two Canadian centers

Recombinant activated factor VII (rFVIIa; NovoSeven, NiaStase, Novo Nordisk, Bagsvaerd, Denmark) was originally developed for the treatment of bleeds in patients with hemophilia and inhibitors. However, the agent is increasingly being employed in "off-label"/unlicensed indications. Consequently there is a need to undertake comprehensive reviews of rFVIIa use; the resulting information will facilitate understanding of how the agent is currently being employed and help to determine trends in its use. This article considers two recently reported reviews describing the use of rFVIIa in two heavily populated regions of Canada--regions with a combined population capture area of approximately 8.5 million people. The reviews report rFVIIa use in a total of 196 patients who collectively received 15,262.8 mg of rFVIIa. Both reviews obtained similar findings and reached similar conclusions: the majority of patients receiving rFVIIa are being treated for "off-label" indications, with numbers of such patients having grown rapidly between the years 2000 and 2005. However, hemophilia patients still account for the vast majority of rFVIIa use, as small numbers of hemophilia patients can consume large quantities of the agent. It is important to be aware of the increasing use of rFVIIa in off-label indications.

Safety of rFVIIa in hemodynamically unstable polytrauma patients with traumatic brain injury: post hoc analysis of 30 patients from a prospective, randomized, placebo-controlled, double-blind clinical trial

BACKGROUND

Trauma is a leading cause of mortality and morbidity, with traumatic brain injury (TBI) and uncontrolled hemorrhage responsible for the majority of these deaths. Recombinant activated factor VIIa (rFVIIa) is being investigated as an adjunctive hemostatic treatment for bleeding refractory to conventional replacement therapy in trauma patients. TBI is a common component of polytrauma injuries. However, the combination of TBI with polytrauma injuries is associated with specific risk factors and treatment modalities somewhat different from those of polytrauma without TBI. Although rFVIIa treatment may offer added potential benefit for patients with combined TBI and polytrauma, its safety in this population has not yet been assessed. We conducted a post hoc sub analysis of patients with TBI and severe blunt polytrauma enrolled into a prospective, international, double-blind, randomized, placebo-controlled study.

METHODS

A post hoc analysis of study data was performed for 143 patients with severe blunt trauma enrolled in a prospective, randomized, placebo-controlled study, evaluating the safety and efficacy of intravenous rFVIIa (200 + 100 + 100 microg/kg) or placebo, to identify patients with a computed tomography (CT) diagnosis of TBI. The incidences of ventilator-free days, intensive care unit-free days, and thromboembolic, serious, and adverse events within the 30-day study period were assessed in this cohort.

RESULTS

Thirty polytrauma patients (placebo, n = 13; rFVIIa, n = 17) were identified as having TBI on CT. No significant differences in rates of mortality (placebo, n = 6, 46%, 90% confidence interval (CI): 22% to 71%; rFVIIa, n = 5, 29%, 90% CI: 12% to 56%; P = 0.19), in median numbers of intensive care unit-free days (placebo = 0, rFVIIa = 3; P = 0.26) or ventilator-free days (placebo = 0, rFVIIa = 10; P = 0.19), or in rates of thromboembolic adverse events (placebo, 15%, 90% CI: 3% to 51%; rFVIIa, 0%, 90% CI: 0% to 53%; P = 0.18) or serious adverse events (placebo, 92%, 90% CI: 68% to 98%; rFVIIa, 82%, 90% CI: 60% to 92%; P = 0.61) were observed between treatment groups.

CONCLUSION

The use of a total dose of 400 (200 + 100 + 100) microg/kg rFVIIa in this group of hemodynamically unstable polytrauma patients with TBI was not associated with an increased risk of mortality or with thromboembolic or adverse events.

Practical considerations when developing guidelines for managing critical bleeding

In the critical care environment, clinicians strive to provide the best treatment possible for patients in desperate need. Such motivation, however, can be a key driver of escalating costs, especially when the use of nonreimbursable therapies goes unchecked or when futile attempts are made to improve outcomes in patients who may not benefit from aggressive management. Proactive intervention in the form of protocols is necessary to guide the use of blood products, coagulation factors, and antifibrinolytic agents. Evidence from clinical trials as well as recommendations from opinion leaders and professional societies should be critically evaluated and used to develop institution-specific protocols. If adopted with multidisciplinary cooperation, such protocols can curb the temptation to rely on anecdotal bedside observations to guide care and treat the patient with critical bleeding. Forming an ad hoc group of an institution's pharmacy and therapeutics committee can be an important step toward this end. The processes that a multidisciplinary group might follow are described, thus providing an idealized example of how pharmacists, working collaboratively with other clinicians and administrators, can be positioned at the center of an institution-wide solution to promote carefully considered, safe, effective, and cost-conscious care.

The successful use of recombinant factor VIIa in a patient with vascular-type Ehlers-Danlos syndrome

Vascular-type Ehlers-Danlos syndrome is an inherited connective tissue disorder resulting in an increased risk of serious peri-operative bleeding during surgery for spontaneous organ or vessel rupture. The excessive bleeding may result in coagulopathy, and thus compound the difficulty in securing surgical haemostasis. With the advent of recombinant factor VIIa, a new therapy has become available for the management of intractable surgical bleeding.

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.