Correcting thrombin generation ex vivo using different haemostatic agents following cardiac surgery requiring the use of cardiopulmonary bypass

Factor Eight Inhibitor Bypassing Activity as First-line Therapy for Coagulopathy in Cardiac Surgery

OBJECTIVES

To compare the outcomes of factor eight inhibitor bypassing activity (FEIBA) versus fresh frozen plasma (FFP) as the primary treatment for postoperative coagulopathy in patients undergoing cardiac surgery.

DESIGN

A retrospective, propensity-matched study.

SETTING

A single, tertiary hospital.

PARTICIPANTS

Patients who underwent noncoronary cardiac surgery with cardiopulmonary bypass between 2015 and 2023.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We stratified patients into 2 groups based on whether they received intraoperative FFP or FEIBA; cases using both were excluded. We analyzed 434 cases, with 197 receiving FFP and 237 receiving FEIBA. After propensity matching, there was no significant difference in the proportion of the patients who required packed red blood cell transfusions (p = 0.08). However, of those who required packed red blood cell transfusions, patients in the FEIBA group required significantly fewer units of packed red blood cells (p < 0.001). Significantly fewer patients in the FEIBA group required platelet (p < 0.001) and cryoprecipitate (p < 0.001) transfusions. The FEIBA group showed decreased prolonged postoperative intubation (p = 0.05), decreased intensive care unit length of stay (p = 0.04), and lower 30-day readmission rates (p = 0.03). There were no differences in the rates of thrombotic complications between the 2 cohorts.

CONCLUSIONS

In the initial treatment of postcardiopulmonary bypass coagulopathy, FEIBA may be more effective than FFP in decreasing blood product transfusions and readmission rates. Further studies are needed to explore the potential routine use of FEIBA as first-line agent in this patient population.

4-Factor Prothrombin Complex Concentrate Dosing Strategies: A Retrospective Evaluation

ObjectivesDetermine indication specific 4-Factor prothrombin complex concentrate (4FPCC) dosing strategies within a hospital system and subsequent effectiveness. Background: 4FPCC is FDA approved for reversal of vitamin K antagonists (VKA) for acute major bleeding or need for urgent surgery/invasive procedure. Since its approval, off label use has expanded to include direct oral anticoagulant reversal and perioperative hemostasis. Optimal dosing strategies remain controversial, and recent studies have evaluated fixed-dose regimens with lower doses than those recommended in product labeling. Methods/Materials: Retrospective cohort with manual chart review for patients who received 4FPCC spanning 2 years. Primary outcome was to characterize dosing. Secondary outcomes were INR normalization, hemostatic efficacy, in-hospital mortality, and renal function change. Results: Of the 300 patients evaluated, 80% received 4FPCC for anticoagulant reversal, with 66% of those for VKA and 34% for DOAC. The remaining 20% received 4FPCC for a non-reversal indication. Of the patients requiring anticoagulation reversal, 25% received doses lower than recommended and 6% received higher. 71% of patients received 4FPCC for life-threatening bleed, and 45% of them had intracranial hemorrhage. Higher mortality with higher than recommended doses was the only statistically significant secondary outcome (P = .018). Conclusion: We found that lower doses than recommended were used in a significant number of patients. The higher than recommended doses group constituted a small proportion of patients and the higher mortality was attributed to patient acuity on presentation. Additional studies evaluating dosing approach are required to determine lowest effective dosing for various indications.

Four-Factor Prothrombin Complex Concentrate in Left Ventricular Assist Device Implantation: Inverse Propensity Score-Weighted Analysis

We compare the effect of intraoperative administration of four-factor prothrombin complex concentrates (PCCs) versus fresh frozen plasma (FFP) on major bleeding, transfusions, and complications. Out of 138 patients undergoing left ventricle assist device (LVAD) implantation, 32 received PCCs as first-line hemostatic agents and 102 FFP (standard group). The crude treatment estimates indicated that, compared with the standard group, the PCC group required more FFP units (odds ratio [OR]: 4.17, 95% confidence interval [CI]: 1.58-11; p = 0.004) intraoperatively, whereas a greater number of patients received FFP at 24 hours (OR: 3.01, 95% CI: 1.19-7.59; p = 0.021) and less packed red blood cells (RBC) at 48 hours (OR: 0.61, 95% CI: 0.01-1.21; p = 0.046). After the inverse probability of treatment weighting (IPTW) adjusted analyses, in the PCC group there was still a higher number of patients who required FFP (OR: 2.9, 95% CI: 1.02-8.25; p = 0.048) or RBC (OR: 6.23, 95% CI: 1.67-23.14; p = 0.007] at 24 hours and RBC at 48 hours (OR: 3.09, 95% CI: 0.89-10.76; p = 0.007). Adverse events and survival were similar before and after the ITPW adjustment. In conclusion, the PCCs, although relatively safe with respect to thrombotic events, were not associated with a reduction of major bleeding and blood product transfusions.

Immediate Higher-Dose Prothrombin Complex Concentrate Without Fresh Frozen Plasma or Fibrinogen Concentrate for Significant Coagulopathic Cardiac Surgical Field Bleeding

BACKGROUND

Treatment of significant coagulopathic cardiac surgical field bleeding with immediate higher-dose prothrombin complex concentrate (PCC) without fresh frozen plasma (FFP) or fibrinogen concentrate is unexplored.

AIMS

To study characteristics, chest drainage, and clinical outcomes of patients with significant coagulopathic surgical field bleeding treated with immediate higher-dose (defined at >15 IU/kg based on factor IX) PCC without FFP or fibrinogen concentrate.

METHODS

We screened sequential cardiac surgery patients. We reviewed electronic blood bank data, Australian Society of Cardiothoracic Surgery database information and anaesthetic, intensive care unit (ICU), ward and radiological charts and electronic data. We identified patients deemed by the operating surgeon to require treatment for significant coagulopathic surgical field bleeding who underwent immediate higher-dose PCC without FFP or fibrinogen concentrate.

RESULTS

Among 168 patients, we identified 30 who underwent immediate higher-dose PCC without FFP or fibrinogen concentrate. Median age was 68 years, 23 were male, 17 underwent coronary artery bypass surgery and three underwent complex surgery (David procedure, redo mitral valve surgery, and redo thoraco-abdominal aneurysm repair). Median dose of PCC was 2,500 IU. In addition, 27% underwent platelets and one underwent cryoprecipitate. Chest drainage at 24 hours was 505 ml. Survival to hospital discharge was 100%. There were no cases of pulmonary embolism, stroke, or other thrombotic events. Stage 1 AKI occurred in one patient.

CONCLUSION

In a pilot cohort of patients with significant coagulopathic surgical field bleeding, immediate higher-dose PCC without FFP or fibrinogen concentrate was feasible and had an acceptable efficacy and safety profile, which justifies future controlled studies.

Perioperative Guidelines on Antiplatelet and Anticoagulant Agents: 2022 Update

Purpose of Review

Multiple guidelines and recommendations have been written to address the perioperative management of antiplatelet and anticoagulant drugs. In this review, we evaluated the recent guidelines in non-cardiac, cardiac, and regional anesthesia. Furthermore, we focused on unresolved problems and novel approaches for optimized perioperative management.

Recent Findings

Vitamin K antagonists should be stopped 3 to 5 days before surgery. Preoperative laboratory testing is recommended. Bridging therapy does not decrease the perioperative thromboembolic risk and might increase perioperative bleeding risk. In patients on direct-acting oral anticoagulants (DOAC), a discontinuation interval of 24 and 48 h in those scheduled for surgery with low and high bleeding risk, respectively, has been shown to be saved. Several guidelines for regional anesthesia recommend a conservative interruption interval of 72 h for DOACs before neuraxial anesthesia. Finally, aspirin is commonly continued in the perioperative period, whereas potent P2Y12 receptor inhibitors should be stopped, drug-specifically, 3 to 7 days before surgery.

Summary

Many guidelines have been published from various societies. Their applicability is limited in emergent or urgent surgery, where novel approaches might be helpful. However, their evidence is commonly based on small series, case reports, or expert opinions.

The association of thrombin generation with bleeding outcomes in cardiac surgery: a prospective observational study

BACKGROUND

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with coagulopathic bleeding. Impaired thrombin generation may be an important cause of coagulopathic bleeding but is poorly measured by existing hemostatic assays. We examined thrombin generation during cardiac surgery, using calibrated automated thrombography, and its association with bleeding outcomes.

METHODS

We conducted a prospective observational study in 100 patients undergoing cardiac surgery with CPB. Calibrated automated thrombography parameters were expressed as a ratio of post-CPB values divided by pre-CPB values. The association of thrombin generation parameters for bleeding outcomes was compared with conventional tests of hemostasis, and the outcomes of patients with the most severe post-CPB impairment in thrombin generation (≥ 80% drop from baseline) were compared with the rest of the cohort.

RESULTS

All 100 patients were included in the final analysis, with a mean age of 63 (12) yr, 31 (31%) female, and 94 (94%) undergoing bypass and/or valve surgery. Post-CPB, peak thrombin decreased by a median of 73% (interquartile range [IQR], 49-91%) (P < 0.001) and total thrombin generation, expressed as the endogenous thrombin potential (ETP), decreased 56% [IQR, 30-83%] (P < 0.001). In patients with ≥ 80% decrease in ETP, 21% required re-exploration for bleeding compared with 7% in the rest of the cohort (P = 0.04), and 48% required medical or surgical treatment for hemostasis compared with 27% in the rest of the cohort (P = 0.04).

CONCLUSIONS

Thrombin generation is significantly impaired by CPB and associated with higher bleeding severity. Clinical studies aimed at the identification and treatment of patients with impaired thrombin generation are warranted.

Comparison of 4-Factor Prothrombin Complex Concentrate With Frozen Plasma for Management of Hemorrhage During and After Cardiac Surgery: A Randomized Pilot Trial

IMPORTANCE

Approximately 15% of patients undergoing cardiac surgery receive frozen plasma (FP) for bleeding. Four-factor prothrombin complex concentrates (PCCs) have logistical and safety advantages over FP and may be a suitable alternative.

OBJECTIVES

To determine the proportion of patients who received PCC and then required FP, explore hemostatic effects and safety, and assess the feasibility of study procedures.

DESIGN, SETTING, AND PARTICIPANTS

Parallel-group randomized pilot study conducted at 2 Canadian hospitals. Adult patients requiring coagulation factor replacement for bleeding during cardiac surgery (from September 23, 2019, to June 19, 2020; final 28-day follow-up visit, July 17, 2020). Data analysis was initiated on September 15, 2020.

INTERVENTIONS

Prothrombin complex concentrate (1500 IU for patients weighing ≤60 kg and 2000 IU for patients weighing >60 kg) or FP (3 U for patients weighing ≤60 kg and 4 U for patients weighing >60 kg), repeated once as needed within 24 hours (FP used for any subsequent doses in both groups). Patients and outcome assessors were blinded to treatment allocation.

MAIN OUTCOMES AND MEASURES

Hemostatic effectiveness (whether patients received any hemostatic therapies from 60 minutes to 4 and 24 hours after initiation of the intervention, amount of allogeneic blood components administered within 24 hours after start of surgery, and avoidance of red cell transfusions within 24 hours after start of surgery), protocol adherence, and adverse events. The analysis set comprised all randomized patients who had undergone cardiac surgery, received at least 1 dose of either treatment, and provided informed consent after surgery.

RESULTS

Of 169 screened patients, 131 were randomized, and 101 were treated (54 with PCC and 47 with FP), provided consent, and were included in the analysis (median age, 64 years; interquartile range [IQR], 54-73 years; 28 [28%] were female; 82 [81%] underwent complex operations). The PCC group received a median 24.9 IU/kg (IQR, 21.8-27.0 IU/kg) of PCC (2 patients [3.7%; 95% CI, 0.4%-12.7%] required FP). The FP group received a median 12.5 mL/kg (IQR, 10.0-15.0 mL/kg) of FP (4 patients [8.5%; 95% CI, 2.4%-20.4%] required >2 doses of FP). Hemostatic therapy was not required at the 4-hour time point for 43 patients (80%) in the PCC group and for 32 patients (68%) in the FP group (P = .25) nor at the 24-hour time point for 41 patients (76%) in the PCC group and for 31 patients (66%) patients in the FP group (P = .28). The median numbers of units for 24-hour cumulative allogeneic transfusions (red blood cells, platelets, and FP) were 6.0 U (IQR, 4.0-11.0 U) in the PCC group and 14.0 U (IQR, 8.0-20.0 U) in the FP group (ratio, 0.58; 95% CI, 0.45-0.77; P < .001). After exclusion of FP administered as part of the investigational medicinal product, the median numbers of units were 6.0 U (IQR, 4.0-11.0 U) in the PCC group and 10.0 U (IQR, 6.0-16.0 U) in the FP group (ratio, 0.80; 95% CI, 0.59-1.08; P = .15). For red blood cells alone, the median numbers were 1.5 U (IQR, 0.0-4.0 U) in the PCC group and 3.0 U (IQR, 1.0-5.0 U) in the FP group (ratio, 0.69; 95% CI, 0.47-0.99; P = .05). During the first 24 hours after start of surgery, 15 patients in the PCC group (28%) and 8 patients in the FP group (17%) received no red blood cells (P = .24). Adverse event profiles were similar.

CONCLUSIONS AND RELEVANCE

This randomized clinical trial found that the study protocols were feasible. Adequately powered randomized clinical trials are warranted to determine whether PCC is a suitable substitute for FP for mitigation of bleeding in cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04114643.

Perioperative Factor Concentrate Use is Associated With More Beneficial Outcomes and Reduced Complication Rates Compared With a Pure Blood Product-Based Strategy in Patients Undergoing Elective Cardiac Surgery: A Propensity Score-Matched Cohort Study

OBJECTIVE

The goal of this study was to compare factor concentrate (FC)-based and blood product-based hemostasis management of coagulopathy in cardiac surgical patients in terms of postoperative bleeding, required blood products, and outcome.

DESIGN

Retrospective, propensity score-matched analysis.

SETTING

Single, tertiary, academic medical center.

PARTICIPANTS

One hundred eighteen matched pairs of 433 consecutive patients scheduled for cardiac surgery in two isolated periods with distinct strategies of hemostasis management.

INTERVENTIONS

Patients received either blood product-based (period I) or FC-based (period II) hemostasis management to treat perioperative coagulopathy.

MEASUREMENTS AND MAIN RESULTS

Patients treated with FC management experienced less postoperative blood loss (907 v 1,153 mL, p = 0.014) and required less red blood cell and fresh frozen plasma transfusion (2.3 v 3.7 units p < 0.0001, and 2.0 v 3.4 units p < 0.0001, respectively) compared with subjects in the blood product-based management group. The frequency of Stage 3 acute kidney injury and 30-day mortality rate were significantly higher in the blood product-based group than in the FC management group (6.8% v 0.8%, p = 0.016, and 7.2% v 0.8%, p = 0.022, respectively). FC management-related thromboembolic events were not registered. The FC strategy was associated with a 2.19-fold decrease in the odds of massive postoperative bleeding (p < 0.0001), a 2.56-fold decrease in the odds of polytransfusion (p < 0.0001), and a 13.16-fold decrease in the odds of early postoperative death (p = 0.003).

CONCLUSIONS

FC-based versus blood product-based management is associated with reduced blood product needs and fewer complications, and was not linked to a higher frequency of thromboembolic events or a decrease in long-term survival in cardiac surgical patients developing perioperative coagulopathy and bleeding.

Challenges of antithrombotic therapy in the management of cardiovascular disease in patients with inherited bleeding disorders: A single-centre experience

INTRODUCTION

Cardiovascular events in patients with inherited bleeding disorders are challenging to manage. The risk of bleeding secondary to antithrombotic treatment must be balanced against the risk of thrombosis secondary to haemostatic therapy.

METHODS

Patients with inherited bleeding disorders with coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI) or atrial fibrillation (AF) from a single centre (2010-2018) are included.

RESULTS

A total of 11 patients undergoing CABG (n = 3), PCI (n = 5) or with AF (n = 3) and a diagnosis of haemophilia A (n = 8), haemophilia B (n = 1), factor XI deficiency (n = 1) and von Willebrand disease (n = 1) managed by a multidisciplinary team are reported. In patients undergoing CABG, factor levels were normalized for 7-10 days with trough levels of 70-80% with severe patients continuing high-dose factor prophylaxis (trough 20-30%) three weeks post-operatively with daily aspirin. In a patient with mild haemophilia A and an inhibitor, recombinant factor VIIa dosing was monitored with thromboelastometry. For PCI, a 3rd-generation drug-eluting stent with one month of dual antiplatelet therapy in addition to high-dose prophylaxis as needed was preferred. Patients with AF and severe haemophilia did not receive antithrombotic treatment, and a thrombin generation assay was used to guide heparin dosing in mild haemophilia.

CONCLUSION

Our experience demonstrates the importance of interdisciplinary communication to identify strategies that decrease the risk of bleeding and thrombosis. The use of extended, increased intensity prophylaxis facilitated antiplatelet therapy. Global assays may help balance the intensity of haemostatic and antithrombotic treatment.

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.

Optimizing Perioperative Blood and Coagulation Management During Cardiac Surgery

Bleeding and transfusion are common in cardiac surgery and associated with poorer outcome. Bleeding is frequently due to coagulopathy caused by the complex interaction between cardiopulmonary bypass, major surgical trauma, anticoagulation management, and perioperative factors. Patient blood management has emerged to improve outcome by the prediction, prevention, monitoring, and treatment of bleeding and transfusion. Each part of this chain has several individual modalities and when combined leads to result in a better outcome. This article reviews the hemostasis disturbances in cardiac surgery with cardiopulmonary bypass and gives an overview of the most important patient blood management strategies.

Preventing and managing catastrophic bleeding during extracorporeal circulation

The use of extracorporeal circulation for cardiac surgery and extracorporeal life support poses tremendous challenges to the hemostatic equilibrium given its diametric tendency to trigger hyper- and hypocoagulopathy. The necessity of anticoagulant therapy to counteract the hemostatic activation by the extracorporeal circuitry compounded by unfavorable patient and surgical factors significantly increase the risk of catastrophic bleeding in patients who require extracorporeal circulation. Preoperative measures, such as stratification of high-risk bleeding patients, and optimization of the modifiable variables, including anemia and thrombocytopenia, provide a crude estimation of the likelihood and may modify the risk of catastrophic bleeding. The anticipation for catastrophic bleeding subsequently prompts the appropriate preparation for potential resuscitation and massive transfusion. Equally important is intraoperative prevention with the prophylactic application of tranexamic acid, an antifibrinolytic agent that has promising benefits in reduction of blood loss and transfusion. In the event of uncontrolled catastrophic bleeding despite preemptive strategies, all effort must be centered on regaining hemostasis through surgical control and damage control resuscitation to protect against worsening coagulopathy and end organ failure. When control of bleeding is reinstated, management should shift focus from systemic therapy to targeted hemostatic therapy aimed at the potential culprits of coagulopathy as identified by point of care hemostatic testing. This review article outlines the strategies to appropriately intervene using prediction, prevention, preparation, protection, and promotion of hemostasis in managing catastrophic bleeding in extracorporeal circulation.

Prothrombin Complex Concentrate in Cardiac Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Prothrombin complex concentrate (PCC) has recently emerged as an effective alternative to fresh frozen plasma (FFP) in treating excessive perioperative bleeding. This systematic review and meta-analysis evaluated the safety and efficacy of PCC administration as first-line treatment for coagulopathy after adult cardiac surgery.

METHODS

PubMed/MEDLINE, EMBASE, and the Cochrane Library were searched from inception to the end of March 2018 to identify eligible articles. Adult patients undergoing cardiac surgery and receiving perioperative PCC were compared with patients receiving FFP.

RESULTS

A total of 861 adult patients from four studies were retrieved. No randomized studies were identified. Pooled odds ratios (ORs) showed that the PCC cohort was associated with a significant reduction in the risk of RBC transfusion (OR, 2.22; 95% confidence interval [CI], 1.45 to 3.40) and units of RBC received (OR, 1.34; 95% CI, 0.78 to 1.90). No differences were observed between the groups for reexploration for bleeding (OR, 1.09; 95% CI, 0.66 to 1.82), chest drain output at 24 hours (OR, 66.36; 95% CI, -82.40 to 216.11), hospital mortality (OR, 0.94; 95% CI, 0.59 to 1.49), stroke (OR, 0.80; 95% CI, 0.41 to 1.56), and occurrence of acute kidney injury (OR, 0.80; 95% CI, 0.58 to 1.12). A trend toward increased risk of renal replacement therapy was observed in the PCC group (OR, 0.41; 95% CI, 0.16 to 1.02).

CONCLUSIONS

In patients with significant bleeding after cardiac surgery, PCC administration seems to be more effective than FFP in reducing perioperative blood transfusions. No additional risks of thromboembolic events or other adverse reactions were observed. Randomized controlled trials are needed to establish the safety of PCC in cardiac surgery definitively.

Enzymatically oxidized phospholipids restore thrombin generation in coagulation factor deficiencies

Hemostatic defects are treated using coagulation factors; however, clot formation also requires a procoagulant phospholipid (PL) surface. Here, we show that innate immune cell–derived enzymatically oxidized phospholipids (eoxPL) termed hydroxyeicosatetraenoic acid–phospholipids (HETE-PLs) restore hemostasis in human and murine conditions of pathological bleeding. HETE-PLs abolished blood loss in murine hemophilia A and enhanced coagulation in factor VIII- (FVIII-), FIX-, and FX-deficient human plasma . HETE-PLs were decreased in platelets from patients after cardiopulmonary bypass (CPB). To explore molecular mechanisms, the ability of eoxPL to stimulate individual isolated coagulation factor/cofactor complexes was tested in vitro. Extrinsic tenase (FVIIa/tissue factor [TF]), intrinsic tenase (FVIIIa/FIXa), and prothrombinase (FVa/FXa) all were enhanced by both HETE-PEs and HETE-PCs, suggesting a common mechanism involving the fatty acid moiety. In plasma, 9-, 15-, and 12-HETE-PLs were more effective than 5-, 11-, or 8-HETE-PLs, indicating positional isomer specificity. Coagulation was enhanced at lower lipid/factor ratios, consistent with a more concentrated area for protein binding. Surface plasmon resonance confirmed binding of FII and FX to HETE-PEs. HETE-PEs increased membrane curvature and thickness, but not surface charge or homogeneity, possibly suggesting increased accessibility to cations/factors. In summary, innate immune-derived eoxPL enhance calcium-dependent coagulation factor function, and their potential utility in bleeding disorders is proposed.

Innate immune-derived enzymatically oxidized phospholipids enhance calcium-dependent coagulation factor function.

Retrospective Review of a Prothrombin Complex Concentrate (Beriplex P/N) for the Management of Perioperative Bleeding Unrelated to Oral Anticoagulation

A multicenter, retrospective, observational study of 4-factor prothrombin complex concentrate (PCC) and/or fresh frozen plasma (FFP) use within routine clinical care unrelated to vitamin K antagonists was conducted. The PCC was administered preprocedure for correction of coagulopathy (prophylactic cohort) and treatment of bleeding postsurgery (treatment cohort). Of the 445 patients included, 40 were in the prophylactic cohort (PCC alone [n = 16], PCC and FFP [n = 5], FFP alone [n = 19]) and 405 were in the treatment cohort (PCC alone [n = 228], PCC and FFP [n = 123], FFP alone [n = 54]). Cardiovascular surgery was the most common setting. PCC doses ranged between 500 and 5000 IU. Effectiveness (assessed retrospectively) was reported as effective in 93.0% in the PCC-only group (95% confidence interval, 89.1% to 95.9%), 78.9% (70.8% to 85.6%) with PCC and FFP, and 86.3% (76.2% to 93.2%) with FFP alone. In the treatment cohort, international normalized ratio was significantly reduced in all 3 groups. In patients who received PCC, the rate of thromboembolic events (1.9%) was below rates in the literature for similar procedures. PCCs offer a potential alternative to FFP in the management of perioperative bleeding unrelated to oral anticoagulant therapy.

A reduction of prothrombin conversion by cardiac surgery with cardiopulmonary bypass shifts the haemostatic balance towards bleeding

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with blood loss and post-surgery thrombotic complications. The process of thrombin generation is disturbed during surgery with CPB because of haemodilution, coagulation factor consumption and heparin administration. We aimed to investigate the changes in thrombin generation during cardiac surgery and its underlying pro- and anticoagulant processes, and to explore the clinical consequences of these changes using in silico experimentation. Plasma was obtained from 29 patients undergoing surgery with CPB before heparinisation, after heparinisation, after haemodilution, and after protamine administration. Thrombin generation was measured and prothrombin conversion and thrombin inactivation were quantified. In silico experimentation was used to investigate the reaction of patients to the administration of procoagulant factors and/or anticoagulant factors. Surgery with CPB causes significant coagulation factor consumption and a reduction of thrombin generation. The total amount of prothrombin converted and the rate of prothrombin conversion decreased during surgery. As the surgery progressed, the relative contribution of α2-macroglobulin-dependent thrombin inhibition increased, at the expense of antithrombin-dependent inhibition. In silico restoration of post-surgical prothrombin conversion to pre-surgical levels increased thrombin generation excessively, whereas co-administration of antithrombin resulted in the normalisation of post-surgical thrombin generation. Thrombin generation is reduced during surgery with cardiopulmonary bypass because of a balance shift between prothrombin conversion and thrombin inactivation. According to in silico predictions of thrombin generation, this new balance increases the risk of thrombotic complications with prothrombin complex concentrate administration, but not if antithrombin is co-administered.

Current use of factor concentrates in pediatric cardiac anesthesia

Excessive bleeding following pediatric cardiopulmonary bypass is associated with increased morbidity and mortality, both from the effects of hemorrhage and the therapies employed to achieve hemostasis. Neonates and infants are especially at risk because their coagulation systems are immature, surgeries are often complex, and cardiopulmonary bypass technologies are inappropriately matched to patient size and physiology. Consequently, these young children receive substantial amounts of adult-derived blood products to restore adequate hemostasis. Adult and pediatric data demonstrate associations between blood product transfusions and adverse patient outcomes. Thus, efforts to limit bleeding after pediatric cardiopulmonary bypass and minimize allogeneic blood product exposure are warranted. The off-label use of factor concentrates, such as fibrinogen concentrate, recombinant activated factor VII, and prothrombin complex concentrates, is increasing as these hemostatic agents appear to offer several advantages over conventional blood products. However, recognizing that these agents have the potential for both benefit and harm, well-designed studies are needed to enhance our knowledge and to determine the optimal use of these agents. In this review, our primary objective was to examine the evidence regarding the use of factor concentrates to treat bleeding after pediatric CPB and identify where further research is required. PubMed, MEDLINE/OVID, The Cochrane Library and the Cochrane Central Register of Controlled Trials (CENTRAL) were systematically searched to identify existing studies.