Safety and Efficacy of Recombinant Activated Factor VII: A Randomized Placebo-Controlled Trial in the Setting of Bleeding After Cardiac Surgery

The coagulopathy of cardiopulmonary bypass

There have been numerous publications on the coagulopathy of cardiopulmonary bypass (CPB). This review provides an introduction to the history and main components of current CPB circuits and summarizes the current knowledge of pathogenesis, prevention, and treatment of the CPB coagulopathy. It encompasses an overview of intra- and postoperative monitoring of coagulation with special emphasis on the near-patient testing, its main complications, and the transfusion support, while taking into account the major changes in the technology used and supportive care provided since its inception.

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.

Off-label use of recombinant activated factor VII in intractable haemorrhage after cardiovascular surgery: an observational study of practices in 23 French cardiac centres (2005-7)

OBJECTIVES

The study aimed to describe French off-label use of rFVIIa for intractable bleeding in major cardiovascular surgery.

METHODS

Retrospective observational analysis of data from 2005 to October 2007 (no formal guidelines were available) was employed. The collect request form was elaborated by a multidisciplinary committee.

RESULTS

Data on 109 patients--37 mechanical cardiac assist devices--were collected, with repeated injection for 24%. Bleeding stopped, decreased or continued in 43%, 37% and 20% of the cases, respectively. For patients treated in the intensive care unit (ICU), hourly bleeding decreased from 365 ± 212 to 115 ± 106 ml h(-1) (p<0.001). The median number of transfused products was 25 (2-90) before and 6 (0-48) after rFVIIa (p<0.001). Most patients had been well compensated with fibrinogen (>1g.l(-1)) and platelets (>50 G.l(-1)) before rFVIIa. The bleeding outcome (cessation, decrease or no change) was associated with the infused dose (81 ± 31, 71 ± 24, 64 ± 23 μg.kg(-1); p = 0.044) and did not differ whether rFVIIa was administered in the operating room (49%) or ICU (51%). Thrombotic events occurred in 13% of patients without assist devices and in 27% of those with them (but without obvious intra-device clotting). The overall 28-day survival rate was 60% and associated with bleeding outcome (p = 0.002).

CONCLUSIONS

rFVIIa rescue therapy was followed by control of bleeding in a substantial number of the patients with seemingly acceptable safety; however, thrombotic risk remains a matter of concern. Our observational study suggests that the dose to be tested prospectively is at least 80 μg.kg(-1).

2011 update to the Society of Thoracic Surgeons and the Society of Cardiovascular Anesthesiologists blood conservation clinical practice guidelines

BACKGROUND

Practice guidelines reflect published literature. Because of the ever changing literature base, it is necessary to update and revise guideline recommendations from time to time. The Society of Thoracic Surgeons recommends review and possible update of previously published guidelines at least every three years. This summary is an update of the blood conservation guideline published in 2007.

METHODS

The search methods used in the current version differ compared to the previously published guideline. Literature searches were conducted using standardized MeSH terms from the National Library of Medicine PUBMED database list of search terms. The following terms comprised the standard baseline search terms for all topics and were connected with the logical 'OR' connector--Extracorporeal circulation (MeSH number E04.292), cardiovascular surgical procedures (MeSH number E04.100), and vascular diseases (MeSH number C14.907). Use of these broad search terms allowed specific topics to be added to the search with the logical 'AND' connector.

RESULTS

In this 2011 guideline update, areas of major revision include: 1) management of dual anti-platelet therapy before operation, 2) use of drugs that augment red blood cell volume or limit blood loss, 3) use of blood derivatives including fresh frozen plasma, Factor XIII, leukoreduced red blood cells, platelet plasmapheresis, recombinant Factor VII, antithrombin III, and Factor IX concentrates, 4) changes in management of blood salvage, 5) use of minimally invasive procedures to limit perioperative bleeding and blood transfusion, 6) recommendations for blood conservation related to extracorporeal membrane oxygenation and cardiopulmonary perfusion, 7) use of topical hemostatic agents, and 8) new insights into the value of team interventions in blood management.

CONCLUSIONS

Much has changed since the previously published 2007 STS blood management guidelines and this document contains new and revised recommendations.

Bleeding and management of coagulopathy

Bleeding after cardiac surgery remains a significant problem, increasing both length of stay and mortality, and is caused by multiple factors including dilutional changes, ongoing fibrinolysis, and platelet dysfunction. The evaluation of coagulopathy is problematic because of the long turnaround time of standard coagulation tests. Algorithms involving point of care testing, including thromboelastography and thromboelastometry, have been published; all have the potential to reduce transfusion requirements. Massive transfusion coagulopathy that occurs in trauma can also be seen in complex aortic surgery and other massive bleeding patients and should prompt consideration of a transfusion protocol involving fixed ratios of fresh frozen plasma, platelets, and red blood cells. Pharmacologic agents such as antifibrinolytics are commonly administered, but a multimodal approach to management is important. Recombinant and purified coagulation products are being studied and provide clinicians specific agents to treat targeted deficiencies. A general multi-modal approach is required and recommendations are made for the management of bleeding and coagulopathy in cardiac surgical patients.

Treatment and monitoring of coagulation abnormalities in children undergoing heart surgery

Bleeding is a considerable clinical problem during and after pediatric heart surgery. While the primary cause of bleeding is surgical trauma, its treatment is often complicated by the presence of coagulopathy. The principle causes of coagulopathy are discussed to provide a context for treatment. The role of laboratory and point of care tests, which aim to identify the cause of bleeding in the individual patient, is also discussed. An attempt is made to examine the current evidence for available therapies, including use of blood products and, more recently proposed, approaches based on human or recombinant factor concentrates.

Off-label recombinant factor VIIa use and thrombosis in children: a multi-center cohort study

OBJECTIVE

To describe the off-label use of recombinant factor VIIa (rFVIIa) in tertiary care pediatric hospitals across the United States and to assess thrombotic events.

STUDY DESIGN

A retrospective multi-center cohort study using the Pediatric Health Information System administrative database. Children 18 years of age or younger who received rFVIIa between 2000 and 2007 were included. A label admission was defined as an admission with an International Classification of Diseases diagnostic code for hemophilia or factor VII deficiency; admissions without these codes were classified as off-label.

RESULTS

There were 4942 rFVIIa admissions, representing 3764 individual subjects; 74% (3655) of the admissions were off-label. There was a 10-fold increase in the annual rate of off-label admissions from 2000 to 2007 (from 2 to 20.8 per 10 000 hospital admissions, P < .001). The mortality rate in the off-label group was 34% (1258/3655). Thrombotic events occurred in 10.9% (399/3655) of the off-label admissions.

CONCLUSIONS

The off-label use of rFVIIa in hospitalized children is increasing rapidly despite the absence of adequate clinical trials demonstrating safety and efficacy. Thrombotic events are common and mortality is high among patients receiving off-label rFVIIa. Further studies are warranted to determine whether these adverse events are attributable to rFVIIa.

Off-label use of recombinant factor VIIa in U.S. hospitals: analysis of hospital records

BACKGROUND

Recombinant factor VIIa (rFVIIa) is approved for treatment of bleeding in patients who have hemophilia with inhibitors but has been applied to a wide range of off-label indications.

OBJECTIVE

To estimate patterns of off-label rFVIIa use in U.S. hospitals.

DESIGN

Retrospective database analysis.

SETTING

Data were extracted from the Premier Perspectives database (Premier, Charlotte, North Carolina), which contains discharge records from a sample of academic and nonacademic U.S. hospitals.

PATIENTS

12 644 hospitalizations for patients who received rFVIIa during a hospital stay.

MEASUREMENTS

Hospital diagnoses and patient dispositions from 1 January 2000 to 31 December 2008. Statistical weights for each hospital were used to provide national estimates of rFVIIa use.

RESULTS

From 2000 to 2008, off-label use of rFVIIa in hospitals increased more than 140-fold, such that in 2008, 97% (95% CI, 96% to 98%) of 18 311 in-hospital uses were off-label. In contrast, in-hospital use for hemophilia increased less than 4-fold and accounted for 2.7% (CI, 1.9% to 3.5%) of use in 2008. Adult and pediatric cardiovascular surgery (29% [CI, 21% to 33%]), body and brain trauma (29% [CI, 19% to 38%]), and intracranial hemorrhage (11% [CI, 7.7% to 14%]) were the most common indications for rFVIIa use. Across all indications, in-hospital mortality was 27% (CI, 19% to 34%) and 43% (CI, 26% to 59%) of patients were discharged to home.

LIMITATION

Accuracy and completeness of the discharge diagnoses and patient medication records in the database sample cannot be verified.

CONCLUSION

Off-label use of rFVIIa in the hospital setting far exceeds use for approved indications. These patterns raise concern about the application of rFVIIa to conditions for which strong supporting evidence is lacking.

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.

Emergency cardiac surgery in patients with acute coronary syndromes: a review of the evidence and perioperative implications of medical and mechanical therapeutics

Patients with acute coronary syndromes who require emergency cardiac surgery present complex management challenges. The early administration of antiplatelet and antithrombotic drugs has improved overall survival for patients with acute myocardial infarction, but to achieve maximal benefit, these drugs are given before coronary anatomy is known and before the decision to perform percutaneous coronary interventions or surgical revascularization has been made. A major bleeding event secondary to these drugs is associated with a high rate of death in medically treated patients with acute coronary syndrome possibly because of subsequent withholding of antiplatelet and antithrombotic therapies that otherwise reduce the rate of death, stroke, or recurrent myocardial infarction. Whether the added risk of bleeding and blood transfusion in cardiac surgical patients receiving such potent antiplatelet or antithrombotic therapy before surgery specifically for acute coronary syndromes affects long-term mortality has not been clearly established. For patients who do proceed to surgery, strategies to minimize bleeding include stopping the anticoagulation therapy and considering platelet and/or coagulation factor transfusion and possibly recombinant-activated factor VIIa administration for refractory bleeding. Mechanical hemodynamic support has emerged as an important option for patients with acute coronary syndromes in cardiogenic shock. For these patients, perioperative considerations include maintaining appropriate anticoagulation, ensuring suitable device flow, and periodically verifying correct device placement. Data supporting the use of these devices are derived from small trials that did not address long-term postoperative outcomes. Future directions of research will seek to optimize the balance between reducing myocardial ischemic risk with antiplatelet and antithrombotics versus the higher rate perioperative bleeding by better risk stratifying surgical candidates and by assessing the effectiveness of newer reversible drugs. The effects of mechanical hemodynamic support on long-term patient outcomes need more stringent analysis.

High-dose tranexamic acid is related to increased risk of generalized seizures after aortic valve replacement

OBJECTIVE

To investigate the incidence of postoperative generalized seizures in patients undergoing aortic valve replacement (AVR) under extracorporeal circulation, who received either high-dose tranexamic acid (TXA) or epsilon aminocaproic acid (EACA) as an antifibrinolytic agent.

METHODS

This retrospective analysis comprised 682 consecutive patients undergoing AVR with or without simultaneous coronary artery bypass surgery. Patients operated on before March 2008 were treated intra-operatively with TXA (100 mg kg⁻¹; n = 341), patients operated on after March 2008 received EACA (50 mg kg⁻¹ loading dose, followed by 25 mg kg⁻¹ h⁻¹, and an additional 5 g in the extracorporeal circuit; n = 341).

RESULTS

Clinically diagnosed generalized seizures were observed within the first 24h postoperatively, more frequently in patients receiving TXA compared with EACA (6.4% vs 0.6%, p < 0.001, difference = 5.8%, 95% confidence interval 3.1-8.5%). Besides the antifibrinolytic agent, three other variables differed significantly between patients with and without postoperative seizures: age (mean (SD), 77.0 (5.9) years vs 73.2 (9.0) years, p = 0.039), preoperative creatinine clearance (55.4 (16.5)ml min⁻¹ vs 72.6 (28.5)ml min⁻¹, p = 0.002), and administration of recombinant activated factor VIIa (3 out of 24 patients (12.5%) vs 8 out of 658 patients (1.2%), p = 0.005). Logistic regression analysis demonstrated a significant impact of the antifibrinolytic drug, creatinine clearance, and the application of recombinant activated factor VIIa on the occurrence of generalized seizures.

CONCLUSIONS

Our results indicate that high-dose TXA is associated with an increased incidence of postoperative generalized seizures in patients undergoing AVR compared with EACA, especially when suffering from renal impairment. A possible association between recombinant activated factor VIIa and the occurrence of postoperative seizures needs further investigation.

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.

Association of coagulation-related and inflammation-related genes and factor VIIc levels with stroke: the Cardiovascular Health Study

BACKGROUND

Thrombosis and inflammation are critical in stroke etiology, but associations of coagulation and inflammation gene variants with stroke, and particularly factor VII levels, are inconclusive.

OBJECTIVES

To test the associations between 736 single-nucleotide polymorphisms (SNPs) between tagging haplotype patterns of 130 coagulation and inflammation genes, and stroke events, in the 5888 participants aged ≥ 65 years of the observational Cardiovascular Health Study cohort.

PATIENTS/METHODS

With 16 years of follow-up, age-adjusted and sex-adjusted Cox models were used to estimate associations of SNPs and FVIIc levels with future stroke.

RESULTS

Eight hundred and fifteen strokes occurred in 5255 genotyped participants without baseline stroke (748 ischemic strokes; 586 among whites). Among whites, six SNPs were associated with stroke, with a nominal P-value of < 0.01: rs6046 and rs3093261 (F7); rs4918851 and rs3781387 (HABP2); and rs3138055 (NFKB1A) and rs4648004 (NFKB1). Two of these SNPs were associated with FVIIc levels (units of percentage activity): rs6046 (β = -18.5, P = 2.38 × 10(-83)) and rs3093261 (β = 2.99, P = 3.93 × 10(-6)). After adjustment for age, sex, race, and cardiovascular risk factors, the association of FVIIc quintiles (Q) with stroke were as follows (hazard ratio; 95% confidence interval): Q1, reference; Q2, 1.4, 1.1-1.9); Q3, 1.1, 0.8-1.5); Q4, 1.5, 1.1-2.0); and Q5, 1.6, 1.2-2.2). Associations between SNPs and stroke were independent of FVIIc levels.

CONCLUSIONS

Variations in FVII-related genes and FVIIc levels were associated with risk of incident ischemic stroke in this elderly cohort, suggesting a potential causal role for FVII in stroke etiology.

Assessment of thrombin generation measured before and after cardiopulmonary bypass surgery and its association with postoperative bleeding

BACKGROUND

Bleeding after cardiopulmonary bypass (CPB) is a major cause of morbidity and mortality and consumes large amounts of blood. Identifying patients at increased risk of bleeding secondary to hemostatic impairment may improve clinical outcomes by allowing early intervention.

METHODS

This present study recruited 77 patients undergoing CPB and measured coagulation screens, coagulation factors, TEG(®), Rotem(®) and thrombin generation (TG) before surgery and 30 min after heparin reversal. The tests were analyzed to investigate whether they identified patients at increased risk of excess bleeding (defined as > 1000 mL) in the first 24 h postoperatively.

RESULTS

Patients who bled > 1000 mL had a lower: platelet count (P < 0.02), factors (F)IX, X and XI (P < 0.005), endogenous thrombin potential (ETP) and an initial rate of TG (P < 0.02) and higher activated partial thromboplastin time (aPTT) (P < 0.001) than patients who bled < 1000 mL. Receiver operating characteristic (ROC) analysis was significant for post-operative TG and aPTT (P < 0.001). Furthermore, reduced pre-operative TG was associated with increased postoperative bleeding (P < 0.02). Pre- and postoperative TG were correlated (ρ = 0.7, P < 0.001). TEG(®), Rotem(®) and prothrombin time (PT) at either time point were not associated with increased bleeding.

CONCLUSION

These data suggest that pre-operative defects in the propagation phase of hemostasis are exacerbated during CPB, contributing to bleeding post-CPB. TG taken both pre- and postoperatively could potentially be used to identify patients at an increased risk of bleeding post-CPB.

Use of recombinant factor VIIa for the prevention and treatment of bleeding in patients without hemophilia: a systematic review and meta-analysis

BACKGROUND

The benefits and risks of off-label use of recombinant factor VIIa in patients without hemophilia are contested. We performed a systematic review to assess the effectiveness and safety of such use.

METHODS

We searched electronic databases including MEDLINE, EMBASE and CENTRAL for randomized controlled trials comparing recombinant factor VIIa with placebo in any patient population except those with hemophilia up to January 2010. Eligible articles were assessed for inclusion, data were extracted, and study quality was evaluated. Outcomes included mortality, blood loss, requirements for red blood cell transfusion, number of patients transfused and thromboembolic events.

RESULTS

We identified 26 trials: 14 on off-label prophylactic use of recombinant factor VIIa (n = 1137) and 12 on off-label therapeutic use (n = 2538). In the studies on prophylactic use, we found no significant difference in mortality or thromboembolic events between the treatment and placebo groups. We found modest benefits favouring recombinant factor VIIa in blood loss (weighted mean difference -276 mL, 95% confidence interval [CI] -411 to -141 mL), red blood cell transfusion (weighted mean difference -281 mL, 95% CI -433 to -129 mL) and number of patients transfused (relative risk 0.71, 95% CI 0.50 to 0.99). In the therapeutic trials, we found a nonsignificant decrease in mortality and a nonsignificant increase in thromboembolic events but no difference in control of bleeding or red blood cell transfusion.

INTERPRETATION

Clinically significant benefits of recombinant factor VIIa as a general hemostatic agent in patients without hemophilia remain unproven. Given its potential risks, such use cannot be recommended, and in most cases, it should be restricted to clinical trials.

Pharmacotherapy for Mechanical Circulatory Support: A Comprehensive Review

Objective

To provide a comprehensive review of the pharmacotherapy associated with the provision of mechanical circulatory support (MCS) to patients with end-stage heart failure and guidance regarding the selection, assessment, and optimization of drug therapy for this population.

Data Sources:

The MEDLINE/PubMed, EMBASE, and Cochrane databases were searched from 1960 to July 2010 for articles published in English using the search terms mechanical circulatory support, ventricular assist system, ventricular assist device, left ventricular assist device, right ventricular assist device, biventricular assist device, total artificial heart, pulsatile, positive displacement, axial, centrifugal, hemostasis, bleeding, hemodynamic, blood pressure, thrombosis, antithrombotic therapy, anticoagulant, antiplatelet, right ventricular failure, ventricular arrhythmia, anemia, arteriovenous malformation, stroke, infection, and clinical pharmacist.

Study Selection And Data Extraction:

All relevant original studies, metaanalyses, systematic reviews, guidelines, and reviews were assessed for inclusion. References from pertinent articles were examined for content not found during the initial search.

Data Synthesis:

MCS has advanced significantly since the first left ventricular assist device was implanted in 1966. Further advancements in MCS technology that occurred in the tatter decade are changing the overall management of end-stage heart failure care and cardiac transplantation. These pumps allow for improved bridge-to-transplant rates, enhanced survival, and quality of life. Pharmacotherapy associated with MCS devices may optimize the performance of the pumps and improve patient outcomes, as well as minimize morbidity related to their adverse effects. This review highlights the knowledge needed to provide appropriate clinical pharmacy services for patients supported by MCS devices.

Conclusions:

The HeartMate II clinical investigators called for the involvement of pharmacists in MCS patient assessment and optimization. Pharmacotherapeutic management of patients supported with MCS devices requires individualized care, with pharmacists as part of the team, based on the characteristics of each pump and recipient.

Intensivtherapie nach Transplantation solider Organe

Der Intensivmedizin kommt eine zentrale Bedeutung in Rahmen der Transplantationsmedizin zu. Aufgrund ihrer marginalen Organfunktion benötigen die Patienten nicht selten bereits im Vorfeld der Transplantation eine intensivmedizinische Versorgung, zu der dann auch die Evaluation und Listung sowie die Koordination des zeitkritischen Transplantationsablaufs gehören können. Die direkte postoperative Betreuung nach komplexen Organtransplantationen bedarf fast ausschließlich der Versorgung im Rahmen von Überwachungsstationen, in denen sowohl direkt transplantationsassoziierte Komplikationen als auch Nebenerkrankungen eine intensivmedizinische Behandlungen notwendig machen. Sie zielt auf die Stabilisierung der Organfunktion, Behandlung begleitender Organdysfunktionen, adäquate Induktion der Immunsuppression und die möglichst frühe Wiedererlangung der Eigenständigkeit des Transplantierten ab.

Predictors of massive transfusion with thoracic aortic procedures involving deep hypothermic circulatory arrest

OBJECTIVE

Massive perioperative blood product transfusion may be required with thoracic aortic operations and is associated with poor outcomes. We analyzed independent predictors of massive transfusion in thoracic aortic surgical patients undergoing deep hypothermic circulatory arrest.

METHODS

The study consisted of 168 consecutive patients undergoing open thoracic aortic procedures involving deep hypothermic circulatory arrest between July 2005 and August 2008. We identified 26 preoperative and procedural variables as potentially related to blood product use, tested for association with total blood products transfused by multivariate linear regression model, and constructed logistic regression model for massive transfusion (requiring ≥ 5 units of transfused packed red blood cells between incision and 48 postoperative hours).

RESULTS

Multivariate linear regression determined that 6 significant variables accounted for 42% of variation in total blood products transfused: age (P = .008), preoperative hemoglobin (P = .04), weight (P = .02), cardiopulmonary bypass time (P < .0001), emergency status (P < .0001), and resternotomy (P < .0001). Final predictive logistic regression model included 1-g/dL increase in preoperative hemoglobin (odds ratio, 0.54; 95% confidence interval, 0.43-0.69; P < .0001), 10-minute increase in cardiopulmonary bypass time (odds ratio, 1.15; 95% confidence interval, 1.05-1.26; P = .0026), and emergency status (odds ratio, 4.02; 95% confidence interval, 1.53-10.55; P = .0047.

CONCLUSIONS

Cardiopulmonary bypass time, emergency status, and preoperative hemoglobin were independent predictors of massive transfusion. These variables, along with weight, age, and resternotomy, were associated with total blood product use in thoracic aortic operations involving deep hypothermic circulatory arrest.

Recombinant Factor VIIa: An Assessment of Evidence Regarding Its Efficacy and Safety in the Off-Label Setting

Recombinant human factor VIIa (rFVIIa) is approved by the US Food and Drug Administration for use in the setting of hemorrhage associated with factor VIII or factor IX inhibitors in patients with congenital or acquired hemophilia. This indication represents only a small number of bleeding conditions. Since it became available, rFVIIa has been increasingly used in the management of off-label indications, ranging from emergent hemostasis in traumatic hemorrhage to prophylactic hemostasis in patients undergoing major surgery. Prominent off-label indications include the management of patients with coagulopathies, such as occurs in trauma patients experiencing massive and uncontrolled hemorrhage, and in patients undergoing cardiovascular surgery with cardiopulmonary bypass. Other occasions for use occur in patients with intact coagulation systems, with nontraumatic intracranial hemorrhage being the most common in this group. Uncertainties regarding the efficacy and safety associated with use of rFVIIa in these off-label scenarios have led to evidence-based assessments of patient outcomes, including mortality, the rate of thromboembolic adverse events, and posttreatment functional status. We review the evidence regarding the efficacy and safety of this important, but controversial, hemostatic agent in the off-label setting.

[Intensive therapy after solid organ transplantation]

Transplantation medicine is an interdisciplinary task and the priority objective is a fast recovery to patient independence. After kidney transplantation the crucial aims are monitoring of transplant perfusion, maintainance of an adequate volume status and avoidance of nephrotoxic medications. Transplantation for patients with advanced chronic liver failure has become more common since the implementation of the model of end stage liver disease (MELD) allocation system which is associated with more complicated proceedings. The essentials of critical care after liver transplantation are monitoring of transplant function, diagnosis of perfusion or biliary tract problems, specific substitution of coagulation factors and hemodynamic optimation due to avoidance of hepatic congestion. Many patients listed for heart transplantation need preoperative intensive care due to impaired heart function. Postoperatively a specific cardiac support with pulmonary arterial dilatators and inotropics is usually necessary. Lung transplantation aims at an improvement of patient quality of life. Postoperative critical care should provide a limitation of the pulmonary arterial pressure, avoidance of volume overload and rapid weaning from the respirator.

Blood conservation in cardiac surgery

Cardiac surgery is one of the largest users of blood and blood products--currently estimated at 15% of U.K. blood stocks. While the blood supply could be considered to be the safest it has ever been, there are well recognised risks associated with the transfusion of red cells and blood products. It is appropriate that attempts should be made to decrease and optimise the transfusion of blood and blood products.

Safety of recombinant activated factor VII in randomized clinical trials

BACKGROUND

The use of recombinant activated factor VII (rFVIIa) on an off-label basis to treat life-threatening bleeding has been associated with a perceived increased risk of thromboembolic complications. However, data from placebo-controlled trials are needed to properly assess the thromboembolic risk. To address this issue, we evaluated the rate of thromboembolic events in all published randomized, placebo-controlled trials of rFVIIa used on an off-label basis.

METHODS

We analyzed data from 35 randomized clinical trials (26 studies involving patients and 9 studies involving healthy volunteers) to determine the frequency of thromboembolic events. The data were pooled with the use of random-effects models to calculate the odds ratios and 95% confidence intervals.

RESULTS

Among 4468 subjects (4119 patients and 349 healthy volunteers), 401 [corrected] had thromboembolic events (9.0%). [corrected] Rates of arterial thromboembolic events among all 4468 subjects were higher among those who received rFVIIa than among those who received placebo (5.5% vs. 3.2%, P=0.003). Rates of venous thromboembolic events were similar among subjects who received rFVIIa and those who received placebo (5.3% vs. 5.7%). Among subjects who received rFVIIa, 2.9% had coronary arterial thromboembolic events, as compared with 1.1% of those who received placebo (P=0.002). Rates of arterial thromboembolic events were higher among subjects who received rFVIIa than among subjects who received placebo, particularly among those who were 65 years of age or older (9.0% vs. 3.8%, P=0.003); the rates were especially high among subjects 75 years of age or older (10.8% vs. 4.1%, P=0.02).

CONCLUSIONS

In a large and comprehensive cohort of persons in placebo-controlled trials of rFVIIa, treatment with high doses of rFVIIa on an off-label basis significantly increased the risk of arterial but not venous thromboembolic events, especially among the elderly. (Funded by Novo Nordisk.).

New parenteral anticoagulants in development

The therapeutic armamentarium of parenteral anticoagulants available to clinicians is mainly composed by unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), fondaparinux, recombinant hirudins (i.e. bivalirudin, desirudin, lepirudin) and argatroban. These drugs are effective and safe for prevention and/or treatment of thromboembolic diseases but they have some drawbacks. Among other inconveniences, UFH requires regular anticoagulant monitoring as a result of variability in the anticoagulant response and there is a risk of serious heparin-induced thrombocytopaenia (HIT). LMWH, fondaparinux and recombinant hirudins are mainly cleared through the kidneys and their use in patients with severe renal insufficiency may be problematic. LMWH is only partially neutralized by protamine while fondaparinux and recombinant hirudins have no specific antidote. Novel anticoagulants in development for parenteral administration include new indirect activated factor Xa (FXa) inhibitors (idrabiotaparinux, ultra-low-molecular-weight heparins [semuloparin, RO-14], new LMWH [M118]), direct FXa inhibitors (otamixaban), direct FIIa inhibitors (flovagatran sodium, pegmusirudin, NU172, HD1-22), direct FXIa inhibitors (BMS-262084, antisense oligonucleotides targeting FXIa, clavatadine), direct FIXa inhibitors (RB-006), FVIIIa inhibitors (TB-402), FVIIa/tissue factor inhibitors (tifacogin, NAPc2, PCI-27483, BMS-593214), FVa inhibitors (drotrecogin alpha activated, ART-123) and dual thrombin/FXa inhibitors (EP217609, tanogitran). These new compounds have the potential to complement established parenteral anticoagulants. In the present review, we discuss the pharmacology of new parenteral anticoagulants, the results of clinical studies, the newly planned or ongoing clinical trials with these compounds, and their potential advantages and drawbacks over existing therapies.

Prothrombin complex concentrate mitigates diffuse bleeding after cardiopulmonary bypass in a porcine model

Background

Extracorporeal circuit priming and intravascular volume expansion during cardiopulmonary bypass (CPB) may lead to dilutional coagulopathy and excessive diffuse postoperative bleeding. Prothrombin complex concentrate (PCC) containing clotting factors II (FII), VII (FVII), IX (FIX), and X (FX) could be of potential value in correcting dilutional coagulopathy and reducing blood loss.

Methods

Anaesthetized pigs underwent CPB with hypothermia for 2 h at 25°C followed by 1 h of normothermia. Approximately 1 h after CPB, animals randomly received either isotonic saline 1 ml kg⁻¹ or PCC 30 IU kg⁻¹ in a volume of 1 ml kg⁻¹. Diffuse coagulopathic bleeding was assessed as suture hole blood loss from a Gore-Tex patch placed over a full-thickness incision in the left carotid artery.

Results

After CPB, levels of FII, FVII, FIX, and FX declined from baseline by 32% to 48%, and PCC fully or partially reversed those deficits. Median suture hole blood loss after administration of saline placebo was 74 ml. PCC reduced suture hole bleeding by a median of 54 ml with a 95% confidence interval of 6–112 ml (P=0.026) compared with saline. PCC, but not saline, normalized skin bleeding time. Peak thrombin generation markedly decreased after CPB, but then returned in PCC-treated animals to a level higher than baseline by 28.7 nM (14.5–41.1 nM; P=0.031).

Conclusions

PCC was effective in correcting dilutional coagulopathy and reducing diffuse bleeding in an in vivo large-animal CPB model. Further research is warranted on PCC as a haemostatic agent in CPB.

Anesthetic concerns for patients with coagulopathy

PURPOSE OF REVIEW

Patients often receive preoperative therapies that interfere with hemostasis, and can present for surgery with underlying hemostatic disorders because of pre-existing preoperative anticoagulation or antiplatelet therapy. Perioperative bleeding can occur following surgery due to multiple causes; however, the addition of pharmacologic agents creates an acquired defect that complicates the surgical injury and may result in increased blood loss. An understanding of the potential impact of anticoagulation therapies on hemostasis is critical in managing these patients. Further, newer agents are evolving in clinical practice that clinicians should be aware of.

RECENT FINDINGS

The anticoagulants and antiplatelet agents that patients are receiving preoperatively apart from unfractionated heparin include low-molecular-weight heparins (LMWHs); a pentasaccharide (fondaparinux); oral anticoagulants: vitamin K antagonists (warfarin), new oral Xa inhibitors (rivaroxaban, apixiban), or the oral direct thrombin inhibitor (DTI) dabigatran; platelet inhibitors: thienopyridines (clopidogrel, ticlopidine, prasugrel) or IIb/IIIa receptor antagonists (tirofiban, abciximab, eptifibatide); or DTIs (r-hirudin, bivalirudin, argatroban).

SUMMARY

There are multiple pharmacologic therapies that surgical patients may be exposed to preoperatively, although there are currently few available methods to antagonize their effects. Often therapeutic prohemostatic pharmacologic approaches are used to treat or prevent bleeding, in addition to transfusional therapies.

Recombinant activated factor VII attenuates major arterial bleeding in noncoagulopathic rabbits

BACKGROUND AND OBJECTIVE

Recombinant activated factor VII (rFVIIa), which is used off-label as an adjuvant therapy for uncontrolled and life-threatening bleeding, might also attenuate intractable bleeding related to macrovascular arterial lesions. Here we evaluated the efficacy of rFVIIa in sealing a large arterial wound in haemostatically competent rabbits.

METHODS

Sixty male New Zealand rabbits were randomly divided into vehicle control and 80 and 200 μg kg⁻¹ rFVIIa groups (n = 20 animals each). A standardized wound of the isolated right carotid artery was made in all rabbits with an 18-G catheter. Bleeding, which was limited by mild compression, was assessed every minute. At 5 min, an intravenous bolus of vehicle or human rFVIIa was given and the animals were further observed for 1 h. Efficacy was assessed from the bleeding duration and blood mass lost. Statistical significance was defined as P less than 0.05. All investigators were blinded to the treatment the animals received.

RESULTS

The bleeding duration and blood mass lost were significantly reduced in both rFVIIa dosage groups as compared with the vehicle control group. For the vehicle, 80 and 200 μg kg⁻¹ rFVIIa groups, the median bleeding durations were 56 min (range 7-60 min), 15 min (range 5-60 min) and 10 min (range 5-60 min), respectively; and the median blood mass losses were 22.5 g (range 1-58 g), 12 g (range 0-36 g) and 5 g (range 0-31 g), respectively. The prothrombin time was shorter in the rFVIIa groups. Visual inspection of the carotid artery and microscopic analysis of the liver and kidney revealed neither gross thrombi nor entrapped microthrombi in any rabbit.

CONCLUSION

Recombinant FVIIa at 80 or 200 μg kg⁻¹ promoted the sealing of a large and slightly compressed arterial wound in rabbits. These results suggest a potential role for the drug in the management of massive bleeds due to an arterial lesion when surgical intervention is not immediately and readily available. Safety should remain a matter of concern.

Prophylactic Fibrinogen Infusion in Cardiac Surgery Patients: Effects on Biomarkers of Coagulation, Fibrinolysis, and Platelet Function

Objective: We have recently reported that prophylactic fibrinogen infusion reduces bleeding after coronary artery bypass grafting (CABG) surgery. Because fibrinogen for the first time was administered to patients without hereditary fibrinogen deficiency or ongoing bleeding, a detailed analysis of the effects of fibrinogen concentrate on biomarkers of coagulation, fibrinolysis, and platelet function was performed. Methods: Twenty CABG patients with preoperative plasma fibrinogen levels <3.8 g/L were included in a prospective study. Patients were randomized to preoperative infusion of 2 g fibrinogen concentrate (fibrinogen group) or no infusion (control group). Activated partial thromboplastin time (aPTT), prothrombin time, activated clotting time, and plasma concentrations of fibrinogen, antithrombin, thrombin-antithrombin complex, prothrombin fragment 1.2, and D-dimer, thromboelastometry, platelet count, and platelet aggregometry were analyzed before and 15 minutes after infusion, and 2 and 24 hours after surgery. Results: Fifteen minutes after infusion of fibrinogen concentrate, fibrinogen plasma levels increased by 0.6 ± 0.2 g/L (P < .001 between groups), and induced minimal changes in aPTT and plasma levels of antithrombin, while remaining variables remained unchanged. After surgery, fibrinogen levels no longer differed between groups. D-dimer was significantly higher after surgery in the fibrinogen group (P = .03), while none of the other markers were statistically different between groups. Conclusions: Infusion of 2 g fibrinogen to cardiac surgery patients, without hereditary or acquired fibrinogen deficiency or ongoing bleeding, results in no or minimal changes in biomarkers reflecting coagulation and platelet function. An increased release of fibrin degradation products was detected after surgery in fibrinogen-treated patients.

Managing fibrinolysis without aprotinin

Cardiopulmonary bypass increases perioperative bleeding and produces a consumptive coagulopathy, which is defined as the simultaneous production of thrombin and fibrinolysis. Thrombin formation and fibrinolysis primarily occur in the surgical wound and peak at the time heparin is reversed by protamine. Neither aprotinin nor lysine analogs successfully control bleeding in many complex procedures, reoperations, aortic resections, or in implantations of mechanical circulatory devices. This analysis reviews the mechanisms involved and current treatment protocols, with the conclusion that changes in treatment protocols rather than use of a specific anti-fibrinolytic drug may provide better control of bleeding in these patients.

Perioperative Coagulopathy, Bleeding, and Hemostasis During Cardiac Surgery

Cardiac surgery patients use 10%-25% of the blood products transfused annually in the United States. The transfusion of red blood cells or blood products has been the subject of intense scrutiny over the past 10 years. Bleeding after cardiac surgery can be surgical or nonsurgical and lead to hemodynamic compromise and surgical reexploration. Because hemorrhage and blood product transfusions are associated with multiple negative outcomes, including increased mortality, it is prudent to understand the mechanisms responsible for nonsurgical bleeding. This review focuses on the physiology of the normal coagulation and fibrinolysis, risk factors associated with patients presenting for cardiac surgery, impairments of normal hemostasis associated with cardiac surgery and cardiopulmonary bypass (CPB), and potential interventions to reduce perioperative blood loss and blood transfusion.

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.