Plasma fibrinogen level, bleeding, and transfusion after on-pump coronary artery bypass grafting surgery: a prospective observational study

Comprehensive perioperative blood management in patients undergoing elective bypass cardiac surgery: Benefit effect of health care education and systematic correction of iron deficiency and anemia on red blood cell transfusion

STUDY OBJECTIVE

The aim of this study was to investigate the efficacy of a two-step patient blood management (PBM) program in red blood cell (RBC) transfusion requirements among patients undergoing elective cardiopulmonary bypass (CPB) surgery.

DESIGN

Prospective, non-randomized, two-step protocol design.

SETTING

Cardiac surgery department of Clinique Pasteur, Toulouse, France.

PATIENTS

897 patients undergoing for elective CPB surgery.

INTERVENTIONS

We conducted a two-steps protocol: PBMe and PBMc. PBMe involved a short quality improvement program for health care workers, while PBMc introduced a systematic approach to pre- and postoperative correction of deficiencies, incorporating iron injections, oral vitamins, and erythropoiesis-stimulating agents.

MEASUREMENTS

The PBM program's effectiveness was evaluated through comparison with a pre-PBM retrospective cohort after propensity score matching. The primary objective was the proportion of patients requiring RBC transfusions during their hospital stay. Secondary objectives were also analyzed.

MAIN RESULTS

After matching, 343 patients were included in each group. Primary outcomes were observed in 35.7% (pre-PBM), 26.7% (PBMe), and 21.1% (PBMc) of patients, resulting in a significant reduction (40.6%) in the overall RBC transfusion rate. Both the PBMe and PBMc groups exhibited significantly lower risks of RBC transfusion compared to the pre-PBM group, with adjusted odds ratios of 0.59 [95% CI 0.44-0.79] and 0.44 [95% CI 0.32-0.60], respectively. Secondary endpoints included reductions in transfusions exceeding 2 units, total RBC units transfused, administration of allogeneic blood products, and total bleeding volume recorded on Day 1. There were no significant differences noted in mortality rates or the duration of hospital stays.

CONCLUSIONS

This study suggests that health care education and systematic deficiency correction are associated with reduced RBC transfusion rates in elective CPB surgery. However, further randomized, controlled studies are needed to validate these findings and refine their clinical application.

Preoperative fibrinogen level and blood transfusions in liver transplantation: A systematic review

BACKGROUND

Orthotopic liver transplantation (OLT) is a major surgery often associated with significant bleeding. We conducted a systematic review to explore the association between preoperative fibrinogen level and intraoperative blood products transfusion, blood loss and clinical outcomes in patients undergoing OLT.

METHODS

We included observational studies conducted in patients undergoing an OLT mostly for end-stage liver disease that reported an association between the preoperative fibrinogen level and our outcomes of interest. Our primary outcome was the intraoperative red blood cell (RBC) transfusion requirements. Our secondary outcomes were intraoperative blood loss, intraoperative transfusion of any blood product, postoperative RBC transfusion, postoperative thrombotic or hemorrhagic complications, and mortality. We used a standardized search strategy. We reported our results mostly descriptively but conducted meta-analyses using random-effect models when judged feasible.

RESULTS

We selected 24 cohort studies reporting at least one of our outcomes. We found that a high preoperative fibrinogen level was associated with fewer intraoperative RBC and other blood products transfusions, and lower blood loss. We also found a lower overall survival in patients with a higher fibrinogen level (pooled hazard ratio [95% CI] of 1.50 [1.23 to 1.84]; 5 studies, n = 1012, I2 = 48%). Only one study formally explored a fibrinogen level threshold effect. Overall, reporting was heterogeneous, and risk of bias was variable mostly because of uncontrolled confounding.

CONCLUSION

A higher preoperative fibrinogen level was associated with fewer intraoperative RBC and other blood products transfusions, lower blood loss, and higher mortality. Further studies may help clarify observed associations and inform guidelines.

Hemostatic Profiles of Patients Who Underwent Transcatheter Versus Surgical Aortic Valve Replacement Versus Percutaneous Coronary Intervention

Guidelines for transcatheter aortic valve replacement (TAVR) antithrombotic prophylaxis are extrapolated predominantly from percutaneous coronary intervention (PCI) data. Here, we examined temporal coagulation changes occurring in the early perioperative period to determine the pathobiologic validity of this supposition. This was a prospective observational study of consecutive patients who underwent transfemoral TAVR (n = 27), PCI (n = 12), or surgical aortic valve replacement (SAVR) requiring cardiopulmonary bypass and cross-clamping (n = 12). Blood samples were taken at 4 time points: T1 (baseline), after general anesthesia or sedation; T2, after heparin administration; T3, at the end of the procedure; and T4, 6 hours after the procedure. The samples were assessed concurrently using standard laboratory coagulation tests and viscoelastic tests of whole blood clotting, including the latest generation thromboelastometry (ROTEM sigma) and thromboelastometry (TEG 6s). Patients in the TAVR cohort were older and a had lower baseline hemoglobin level than patients in the PCI and SAVR cohorts. The baseline platelet function was similar between the TAVR and PCI cohorts and impaired in the SAVR cohort Figure S1. The baseline hemostatic measures were comparable among cohorts. Regarding the per-patient change from baseline, the TAVR cohort showed an overall more prothrombotic state than the other cohorts, with the most marked differences from the SAVR cohort after intraoperative heparin administration and from the PCI cohorts 6 hours after the procedure. In addition, the ROTEM and TEG parameters were well correlated but not interchangeable. In conclusion, patients who underwent TAVR have a more prothrombotic hemostatic profile than PCI and SAVR patients. These findings question the current guidelines that extrapolate antithrombotic regimens from PCI to TAVR settings.

Blood Product Replacement for Postpartum Hemorrhage

Consideration for blood products replacement in postpartum hemorrhage should be given when blood loss exceeds 1.5 L or when an estimated 25% of blood has been lost. In cases of massive hemorrhage, standardized transfusion protocols have been shown to improve maternal morbidity and mortality. Most protocols recommend a balanced transfusion involving a 1:1:1 ratio of packed red blood cells, platelets, and fresh frozen plasma. Alternatives such as cryoprecipitate, fibrinogen concentrate, and prothrombin complex concentrates can be used in select clinical situations. Although transfusion of blood products can be lifesaving, it does have associated risks.

Plasma Fibrinogen as a Predictor of Perioperative-Blood-Component Transfusion in Major-Nontraumatic-Orthopedic-Surgery Patients: A Cohort Study

There is a trend towards increased perioperative bleeding in patients with plasma fibrinogen levels < 200 mg/dL^-1. This study aimed to assess whether there is an association between preoperative fibrinogen levels and perioperative blood-product transfusion up to 48 h after major orthopedic surgery. This cohort study included 195 patients who underwent primary or revision hip arthroplasty for nontraumatic etiologies. Plasma fibrinogen, blood count, coagulation tests, and platelet count were measured preoperatively. A plasma fibrinogen level of 200 mg/dL^-1 was the cutoff value used to predict blood transfusion. The mean (SD) plasma fibrinogen level was 325 (83) mg/dL^-1. Only thirteen patients had levels < 200 mg/dL^-1, and only one of them received a blood transfusion, with an absolute risk of 7.69% (1/13; 95%CI: 1.37-33.31%). Preoperative plasma fibrinogen levels were not associated with the need for blood transfusion (p = 0.745). The sensitivity and the positive predictive value of plasma fibrinogen < 200 mg/dL^-1 as a predictor of blood transfusion were 4.17% (95%CI: 0.11-21.12%) and 7.69% (95%CI: 1.12-37.99%), respectively. Test accuracy was 82.05% (95%CI: 75.93-87.17%), but positive and negative likelihood ratios were poor. Therefore, preoperative plasma fibrinogen level in hip-arthroplasty patients was not associated with the need for blood-product transfusion.

Preoperative fibrinogen level and postcardiac surgery morbidity and mortality rates

BACKGROUND

High preoperative fibrinogen levels are associated with reduced bleeding rates after cardiac surgery. Fibrinogen is directly involved in inflammatory processes and is a cardiovascular risk factors. Whether high fibrinogen levels before cardiac surgery are a risk factor for mortality or morbidity remains unclear.

AIMS

This study aimed to examine the association between preoperative fibrinogen levels and mortality and morbidity rates after cardiac surgery.

SETTINGS AND DESIGN

This is a single-center retrospective study.

MATERIAL AND METHODS

Patients (n = 1628) were divided into high (HFGr) and normal (NFGr) fibrinogen level groups, based on the cutoff value of 3.3 g/L, derived from the receiver operating characteristic (ROC) curve analysis. The primary outcome was the 30-day mortality rate. The rates of postoperative complications, including postoperative bleeding and transfusion rates, were examined.

STATISTICAL ANALYSIS

Between-group comparisons were performed with the Mann-Whitney U test and Chi-squared test, as suitable. Model discriminative power was examined with the area under the ROC curve.

RESULTS

The HFGr and NFGr included 1103 and 525 patients, respectively. Mortality rate was higher in the HFGr than in the NFGr (2.7% vs. 1.1%, P = 0.04). The 12-h bleeding volume (280 mL [195-400] vs. 305 mL [225-435], P = 0.0003) and 24-h bleeding volume values (400 mL [300-550] vs. 450 mL [340-620], P &lt; 0.0001) were lower in the HFGr than in the NFGr. However, the rate of red blood cell transfusion during hospitalization was higher in the HFGr than in the NFGr (21.7% vs. 5.9%, P = 0.0103). Major complications were more frequent in the HFGr than in the NFGr.

CONCLUSION

High fibrinogen levels were associated with reduced postoperative bleeding volume and increased mortality and morbidity rates.

Can C-reactive protein predict coagulation in off pump coronary artery bypass grafting? A cohort study

Background

Previous study found that C-reactive protein (CRP) can predict bleeding after on-pump CABG. To evaluate whether preoperative C-reactive protein (CRP) can be a novel marker of postoperative bleeding in patients having off-pump coronary artery bypass grafting (CABG).

Methods

This is a retrospective cohort study. Multiple variable regression analyses were performed. 537 patients undergoing off-pump isolated primary CABG at Fuwai Hospital from September 2017 to July 2018 were recorded. The primary endpoint was bleeding volume within 24 h after surgery.

Results

Data of 537 patients undergoing off-pump isolated primary CABG at Fuwai Hospital were recorded. The correlations between bleeding volume within 24 h after surgery and preoperative data were analyzed with univariate and multivariate linear regression. Much more preoperative CRP concentration (B = −0.089, P < 0.05) was associated with less postoperative bleeding volume and fibrinogen (B = 0.594, p < 0.001).

Conclusions

Preoperative CRP concentration is independently correlated with the postoperative volume of bleeding within 24 h. CRP may become a novel coagulation index in coronary artery atherosclerotic disease.

Does Abnormal Preoperative Coagulation Status Lead to More Perioperative Blood Loss in Spinal Deformity Correction Surgery?

This study aims to analyze the potential association between the preoperative coagulation status and perioperative blood loss in spinal deformity correction surgery. The preoperative coagulation status and estimated blood loss (EBL) during operation, postoperative wound drainage, and allogeneic transfusion during and after operation were recorded and analyzed. Among the 164 patients, 26 had a longer prothrombin time (PT), 13 had a lower fibrinogen level, 55 had a longer activated partial thromboplastin time (APTT), and 2 had a longer thrombin time (TT), and the platelet count (PLT) was all normal or higher than the normal level. The mean EBL per surgical level was 77.8 ml (range, 22–267 ml), and the mean drainage per surgical level was 52.7 ml (range, 7–168 ml). Fifty-five patients and 12 patients underwent allogeneic transfusion during and after the operation, respectively. The differences in EBL per surgical level, mean drainage per surgical level, the occurrences of allogeneic transfusion during and after operation between the patients with a longer PT, lower fibrinogen level, longer APTT or longer TT, and the normal controls were not significant (all P’s > 0.05). The Spearman correlation analysis showed that there was no correlation between PT, fibrinogen, APTT, TT or PLT with EBL per surgical level, mean drainage per surgical level, or allogeneic transfusion during and after the operation (all P’s > 0.05). The abnormal preoperative coagulation status but not hemophilia does not lead to more perioperative blood loss or a higher rate of perioperative allogeneic transfusion in spinal deformity correction surgery.

Association Between Preoperative Fibrinogen-to-Albumin Ratio and All-Cause Mortality After Off-Pump Coronary Artery Bypass Grafting: A Retrospective Observational Study

BACKGROUND

The fibrinogen-to-albumin ratio (FAR) is a recently introduced prognostic marker for patients with coronary artery disease. The present study investigated whether the FAR is associated with clinical outcome after off-pump coronary artery bypass grafting (OPCAB).

METHODS

We retrospectively reviewed 1759 patients who underwent OPCAB (median duration of follow-up, 46 months). To evaluate the association between FAR and mortality in OPCAB patients, time-dependent coefficient Cox regression analyses were used to assess the association between FAR and all-cause mortality.

RESULTS

In multivariable time-dependent coefficient Cox regression analyses, preoperative FAR was an independent risk factor for all-cause mortality after OPCAB (adjusted hazard ratio, 1.051; 95% confidence interval, 1.021-1.082). In the restricted cubic spline function curve of the multivariable-adjusted relationship between the preoperative FARs, a linear increase in the relative hazard for all-cause mortality was observed as the FAR increased (P = .001).

CONCLUSIONS

A higher FAR is associated with increased all-cause mortality after OPCAB. The preoperative FAR could be a prognostic factor for predicting higher mortality after OPCAB.

Evaluation of health outcomes after the implementation of rotational thromboelastometry in patients undergoing cardiac surgery

BACKGROUND

Viscoelastic tests (rotational thromboelastometry, ROTEM^®), together with the implementation of a specific algorithm for coagulation management in cardiac surgery, enable perioperative coagulopathy to be better controlled.

METHODS

Retrospective cohort study including 675 patients who underwent cardiac surgery with cardiopulmonary bypass. The incidence of allogeneic blood transfusions and clinical postoperative complications were analyzed before and after ROTEM^® implementation.

RESULTS

Following viscoelastic testing and the implementation of a specific algorithm for coagulation management, the incidence of any allogeneic blood transfusion decreased (41.4% vs 31.9%, p = .026) during the perioperative period. In the group monitored with ROTEM^®, decreased incidence of transfusion was observed for packed red blood cells (31.3% vs 19.8%, p = .002), fresh frozen plasma (9.8% vs 3.8%, p = .008), prothrombin complex concentrate administration (0.9% vs 0.3%, p = .599) and activated recombinant factor VII (0.3% vs 0.0%, p = .603). Increased incidence was observed for platelet transfusion (4.8% vs 6.8%, p = .530) and fibrinogen concentrate (0.9% vs 3.5%, p = .066), tranexamic acid (0.0% vs 0.6%, p = .370) and protamine administration (0.6% vs 0.9%, p = .908). Similar results were observed in the postoperative period, but with a decreased incidence of platelet transfusion (4.8% vs 3.8%, p = .813). In addition, statistically significant reductions were detected in the incidence of postoperative bleeding (9.5% vs 5.3%, p = .037), surgical reexploration (6.0% vs 2.9%, p = .035), and length of Intensive Care Unit (ICU) stay (6.0 days vs 5.3 days, p = .026).

CONCLUSIONS

The monitoring of hemostasis by ROTEM^® in cardiac surgery, was associated with decreased incidence of allogeneic blood transfusion, clinical hematologic postoperative complications and lengths of ICU stay.

Evaluation of plasma fibrinogen levels before and after coronary artery bypass graft surgery and its association with the need for blood products

Background:

The present study investigated the plasma level of fibrinogen before and after removing the pump in coronary artery bypass graft (CABG) surgery and its relationship with the need for blood products.

Materials and Methods:

The present study was performed on 60 patients who were candidates for CABG surgery. The fibrinogen level of these patients was assessed and recorded before surgery and immediately after removing the pump. In addition, their hemoglobin level was recorded before the operation and 2 h after. In addition, the number and type of blood products transfusion were recorded intraoperatively and postoperatively and also at the intensive care unit.

Results:

Patients’ fibrinogen level after removing the pump with the mean of 130.53 ± 122.01 mg/dl decreased significantly compared to before surgery with the mean of mg/dl 224.95 ± 132.88 mg/dl (P < 0.001). In addition, the prognostic value of fibrinogen after removing the pump in determining the postoperative need of blood transfusion showed that the cut-off value of fibrinogen was < 196 mg/dl with a sensitivity of 16.82% and specificity of 80%, but it was not statistically significant (area under the curve [95% confidence interval]: 0.519 [0.350–0.689]; P = 0.825).

Conclusion:

According to the results of the present study, due to significant changes in fibrinogen levels after removing the pump compared to preoperation, it seems that this factor can play an important role in prognosis of the need to postoperative blood transfusion, although the prognostic value and the critical point mentioned in our study was not significant and it is required to do further studies.

Fibrinogen Replacement in Haemostatic Resuscitation: Dose, Laboratory Targets and Product Choice

Fibrinogen is a key coagulation protein that is necessary for the formation of stable clots. Fibrinogen levels have been reported to be one of the first to fall during major haemorrhage reflecting consumption, dilution and fibrinogenolysis. Its role in acquired major haemorrhage, both in relation to the contribution it plays to the coagulopathy of major bleeding that can exacerbate bleeding and how effective fibrinogen supplementation can be at improving clinical outcomes, has received a great deal of attention over the last 10 - 15 years. This commentary focuses on just three of the more recent publications from the last 5 years that provide some of the evidence behind how we can think about fibrinogen as a haemostatic treatment for acquired major haemorrhage and how we can use the laboratory thresholds to guide therapy.

Fibrinogen Level Combined With Platelet Count for Predicting Hemorrhagic Transformation in Acute Ischemic Stroke Patients Treated With Mechanical Thrombectomy

A serious complication of acute ischemic stroke (AIS) after mechanical thrombectomy (MT) is hemorrhagic transformation (HT), which is potentially associated with clinical deterioration. This study examined predictors of HT following MT in AIS patients. Patients with AIS due to large artery occlusion in the anterior circulation, treated with MT and successfully recanalized (modified Thrombolysis in Cerebral Infarction score 2b/3), were studied retrospectively. HT was evaluated by computed tomography (CT) 24 h after MT and was diagnosed and classified into parenchymal hematoma (PH) and hemorrhagic infarction (HI). Multivariate logistic regression models were used to determine the risk factors for HT. Receiver operating characteristic (ROC) curve analysis was performed to determine the predictive utility of risk factors for HT. We enrolled 135 patients: 49 in the HT group and 86 in the non-HT group. The two groups differed significantly in baseline fibrinogen levels (p = 0.003) and platelet counts (p = 0.006). Multivariate logistic regression analyses showed that lower fibrinogen levels [odds ratio (OR), 0.41; 95% CI, 0.23–0.72; p = 0.002] and platelet counts (OR, 0.58; 95% CI, 0.33–0.99; p = 0.048) were independently associated with a higher risk of HT. Together, the binary variates fibrinogen and platelets well-predicted HT (area under the curve, 0.703; specificity, 77.9%; sensitivity, 55.1%). The combination of fibrinogen <2.165 g/L and platelets <171.5 × 10⁹/L was the strongest predictor of HT (OR, 23.17; 95% CI, 5.75–126.80; p < 0.0001). Our study suggests that lower baseline fibrinogen levels and platelet counts may be risk factors for HT in AIS patients following MT and reperfusion. Specifically, the combination of fibrinogen level and platelet count may predict the risk of HT after MT in these patients.

Viscoelastic testing to assess the effects of rapid fibrinogen concentrate administration after cardiopulmonary bypass: insights from the REPLACE study

Haemorrhage during and following surgery results in increased morbidity and mortality. Low plasma fibrinogen levels have been associated with increased blood loss and transfusion requirements. Fibrinogen supplementation has been shown to reduce bleeding in coagulopathic patients. This post hoc study evaluated fibrinogen repletion and pharmacokinetic data from the REPLACE study. One hundred and fifty-two adult patients undergoing elective aortic surgery requiring cardiopulmonary bypass (CPB) with defined bleeding of 60-250 g at first 5 min bleeding mass were included in the phase III trial. Patients were randomized to receive either fibrinogen concentrate (FCH) or placebo following CPB removal. Plasma fibrinogen levels and viscoelastic testing parameters (ROTEM-based FIBTEM and EXTEM assays) were measured before, during, and after study treatment administration. A mean dose of 6.3 g FCH was administered in the FCH group, with a median infusion duration of 2 min. Immediately following completion of FCH administration, a rapid increase in plasma fibrinogen levels to near baseline (median change from baseline -0.10 g/l) was seen in the FCH group but not in the placebo group (median change from baseline -1.29 g/l). FCH administration also caused an immediate increase in FIBTEM maximum clot firmness (MCF) to 23 mm and improvements in EXTEM coagulation time and clot formation time by the end of infusion. There was a strong correlation between the plasma fibrinogen level and FIBTEM MCF. Treatment with high doses of FCH with a rapid infusion time resulted in immediate recovery to baseline levels of plasma fibrinogen and viscoelastic testing parameters.

Thrombotic activation before and after total hip arthroplasty. A prospective cohort study

BACKGROUND

Total hip arthroplasty (THA) causes acute blood loss. It may lead to a deficiency in coagulation factors, which, in turn, may lead to increased bleeding during the postoperative period.

METHODS

Thirty patients (18 women) with a mean age of 67 years (range: 63-72 years) participated in this prospective diagnostic study. THA was performed without tranexamic acid administration in the perioperative period. Activities of clotting factors II, VIII, X, and fibrinogen concentration were evaluated before surgery, 6 hours after the procedure, 2, 4, and 6 days after the operation. All laboratory tests were performed using ACL TOP 500 CTS analyzer.

RESULTS

No thromboembolic complications were noted during hospitalization. Mean fibrinogen concentration was 366 mg/dL before surgery, which decreased to 311 mg/dL 6 hours after the operation and peaked at 827 mg/dL on the 4th day after the procedure. Activities of factors II and X decreased on the second and fourth days after surgery. Although the activity of factor VIII decreased after the procedure, it remained within the normal range. Increased baseline fibrinogen concentrations were observed in 6 out of 30 (20%) patients. Mean blood loss was 1332 mL (range, 183-2479 mL) and did not correlate with changes in clotting factor activities.

CONCLUSIONS

In patients undergoing THA, fibrinogen acts as an acute-phase protein. Activities of clotting factors II and X normalize within 6 days, and although the activity of factor VIII decreases, it remains within the normal range.

TRIAL REGISTRATION

The study was pre-registered May 1st, 2020 on ClinicalTrials.gov.

Association of Plasma Fibrinogen and Thromboelastography With Blood Loss in Complex Cardiac Surgery

Postoperative coagulopathic bleeding is common in cardiac surgery and is associated with increased morbidity and mortality. Ideally, real-time information on in-vivo coagulation should be available. However, up to now it is unclear which perioperative coagulation parameters can be used best to accurately identify patients at increased risk of bleeding. The present study analyzed the associations of perioperative fibrinogen concentrations and whole blood viscoelastic tests with postoperative bleeding in 89 patients undergoing combined cardiac surgery procedures. Postoperative bleeding was recorded until 24 hours after surgery. Regression analyses were performed to establish associations between blood loss and coagulation parameters after cardiopulmonary bypass including a prediction model with known confounding factors for bleeding. Coagulation tests show large changes over the perioperative course with the strongest coagulopathic deviations from baseline after cardiopulmonary bypass. After adjustment for multiple confounders, viscoelastic clot strength instead of fibrinogen concentration showed a similar performance for 24 hour blood loss and a better performance for 6 hour blood loss. This makes intraoperative viscoelastic testing a useful tool to strengthen early clinical decision-making with the potential to reduce perioperative blood transfusions.

The role of cryoprecipitate in human and canine transfusion medicine

OBJECTIVE

To evaluate the current role of cryoprecipitate in human and canine transfusion medicine.

DATA SOURCES

Human and veterinary scientific reviews and original studies found using PubMed and CAB Abstract search engines were reviewed.

HUMAN DATA SYNTHESIS

In the human critical care setting, cryoprecipitate is predominantly used for fibrinogen replenishment in bleeding patients with acute traumatic coagulopathy. Other coagulopathic patient cohorts for whom cryoprecipitate is recommended include those undergoing cardiovascular or obstetric procedures or patients bleeding from advanced liver disease. Preferential selection of cryoprecipitate versus fibrinogen concentrate (when available) is currently being investigated. Also a matter of ongoing debate is whether to administer this product as part of a fixed-dose massive hemorrhage protocol or to incorporate it into a goal-directed transfusion algorithm applied to the individual bleeding patient.

VETERINARY DATA SYNTHESIS

Although there are sporadic reports of the use of cryoprecipitate in dogs with heritable coagulopathies, there are few to no data pertaining to its use in acquired hypofibrinogenemic states. Low fibrinogen in dogs (as in people) has been documented with acute traumatic coagulopathy, advanced liver disease, and disseminated intravascular coagulation. Bleeding secondary to these hypocoagulable states may be amenable to cryoprecipitate therapy. Indications for preferential selection of cryoprecipitate (versus fresh frozen plasma) remain to be determined.

CONCLUSIONS

In the United States, cryoprecipitate remains the standard of care for fibrinogen replenishment in the bleeding human trauma patient. Its preferential selection for this purpose is the subject of several ongoing human clinical trials. Timely incorporation of cryoprecipitate into the transfusion protocol of the individual bleeding patient with hypofibrinogenemia may conserve blood products, mitigate adverse transfusion-related events, and improve patient outcomes. Cryoprecipitate is readily available, effective, and safe for use in dogs. The role of this blood product in clinical canine patients with acquired coagulopathy remains unknown.

Factors associated with excessive bleeding following elective on-pump coronary artery bypass grafting

INTRODUCTION

Excessive bleeding following cardiac surgery is associated with worse outcomes. We aimed to analyze preoperative and operative factors associated with excessive bleeding in coronary artery bypass patients to better understand which patients are under increased risk.

METHODS

The study was conducted as an observational study in a tertiary center for cardiac surgery by retrospective analysis of the hospital database. Patients were grouped according to chest tube output within the postoperative 24 h. Patients in the 4th percentile of chest tube output per kilogram were categorized as having excessive bleeding. Patients with excessive bleeding were compared with the other patients for preoperative and operative factors. Factors significant in univariate analysis were carried onto the multivariate analysis.

RESULTS

Patients with excessive bleeding were more likely to be males (91.4% vs. 78.7%, p = .002), have lower body mass index (BMI) (27.4 vs. 29.2, p < .001), and low platelets (6.9% vs. 1.5%, p = .006). Cardiopulmonary bypass (101.8 vs. 110.9 min, p = .022) time was longer in the excessive bleeding group. Patients with excessive bleeding were more likely to have more than three vessels revascularized. Male sex, lower BMI, low platelets, and longer cardiopulmonary bypass time were independently associated with increased bleeding.

CONCLUSION

Male sex, lower BMI, low platelet count, and longer cardiopulmonary bypass time are associated with extensive bleeding after elective coronary artery bypass surgery (CABG). Patients with higher bleeding risk should be identified preoperatively to account for adverse outcomes after CABG.

MiR-223 levels predicting perioperative bleeding in off-pump coronary artery bypass grafting

Background

To investigate the predictive value of platelet-related microRNAs (miRNAs) for bleeding during and after off-pump coronary artery bypass grafting (OPCABG) and the influence of dual antiplatelet therapy (DAPT) on miRNAs.

Methods

This prospective study included 59 patients scheduled for OPCABG. The plasma miR-126 and miR-223 levels were measured and platelet aggregation was determined by thromboelastography during DAPT. The plasma miRNA levels were compared between patients treated with ticagrelor or clopidogrel. Multivariable logistic regression analysis was performed to determine the independent risk factors for bleeding during and after surgery. Active bleeding was defined as a blood loss >1.5 mL/kg/h for 6 consecutive hours within the first 24 hours or in case of reoperation during the first 12 postoperative hours. Severe perioperative bleeding was defined using the universal definition of perioperative bleeding in adult cardiac surgery.

Results

Higher circulating miR-223 levels [odds ratio (OR) =1.348, 95% confidence interval (CI): 1.001–1.814, P=0.047] and lower body mass index (OR =0.648, 95% CI: 0.428–0.980, P=0.040) were independent predictors for severe perioperative bleeding in OPCABG. Ticagrelor treatment led to significant increases in circulating miR-223 levels compared with clopidogrel treatment.

Conclusions

The plasma miR-223 levels served as a predictor for bleeding during and after OPCABG. Circulating miR-223 levels were significantly elevated with ticagrelor treatment compared with clopidogrel treatment. MiR-223 may be a novel biomarker for bleeding in cardiac surgery and can help explain the different efficacies of ticagrelor and clopidogrel.

The role of exogenous Fibrinogen in cardiac surgery: stop bleeding or induce cardiovascular disease

The surgical treatment contributes to broad variety of cardiovascular diseases (CVD). Due to many involved factors in preoperative bleeding, it is almost difficult to perform better Haemostatic approach. Fibrinogen is a major blood glycoprotein and a coagulation factor which decreases postoperative bleeding. It has a potential role in platelet activation and bleeding inhibition; it may reflect the inflammatory responses and be related to the endothelial dysfunction. Fibrinogen can act as a pro-inflammatory element via increasing some inflammatory markers including IL-6, tumor necrosis factor-α (TNF-α), monocyte chemo attractant protein (MCP-1), macrophage inflammatory protein-1 (MIP-1a and b), matrix metalloproteinase (MMP-1 and MMP-9) and Toll-like Receptors (TLRs); through activation of these factors, fibrinogen may induce some inflammatory mechanisms such as focal adhesion kinase (FAK), mitogen-activated protein kinases (MAPK) and nuclear factor κB (NF-κB) pathways. It may cause endothelial dysfunction by increasing P and E-selection, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) levels which activate MAPK and NF-κB pathways. This factor is also associated with increased exocytosed von Willebrand factor (vWF) as well as activation of Rho-GTPase mechanism. All of these data demonstrate the dual role of fibrinogen in cardiac surgeries, bleeding inhibition and CVD. Therefore, identifying the CVD factors is helpful for designing preventive strategies and alternative drugs.

The Need for Red Cell Support During Non-Cardiac Surgery Is Associated to Pre-Transfusion Levels of FXIII and the Platelet Count

Unexpected intraoperative bleeding is associated with a reduced availability of crosslinking capacity (provided through factor XIII (FXIII)) per unit of generated thrombin. Furthermore, FXIII deficiency and thrombocytopenia (but not fibrinogen deficiency) are the most prevalent modulators of clot firmness in the immediate postoperative setting. In this study, we therefore evaluated whether levels of FXIII, fibrinogen, or the platelet count influenced the probability of intraoperative red cell transfusions in patients in the operating theatre. This retrospective study was comprised of 1023 patients, which were in need of blood product support in the operating theatre and of which 443 received red cell transfusions. Due to standard operating procedures, FXIII activity, fibrinogen concentration, and platelet count were measured before transfusion took place, but without influencing the decision to transfuse. FXIII deficiency was frequent (50%), as was thrombocytopenia (49%), but not fibrinogen deficiency (9%). FXIII deficiency was associated with a significantly increased probability to receive red cell transfusions (OR 4.58, 95% CI 3.46–6.05) as was thrombocytopenia (OR 1.94, 95% CI 1.47–2.56), but not fibrinogen deficiency (OR 1.09, 95% CI 0.67–1.76). Similar results were seen for cut-off independent evaluations (receiver operating characteristics (ROC) curves, using continuously distributed variables), where the areas under the curves (AUC) of red cell transfusion for FXIII activity was 0.744 (95% CI 0.716–0.770)/0.632 (95% CI 0.601–0.661) for the platelet count, and 0.578 (95% CI 0.547–0.609) for fibrinogen concentration. All AUCs were significantly different from each other (p < 0.0001 and p = 0.0106, respectively), indicating that FXIII activity was a significantly better predictor of red blood cell (RBC) transfusion than platelet count and fibrinogen concentration. These results suggest that pre-transfusion FXIII activity and to a lesser extent the platelet count influence the probability of intraoperative red cell transfusions. Modifying FXIII activity and/or the platelet count might influence the need for downstream red cell transfusion, thus potentially reducing transfusion associated morbidity. This, however, needs confirmation in future studies.

U-shaped relationship between pre-operative plasma fibrinogen levels and severe peri-operative bleeding in cardiac surgery

BACKGROUND

An inverse linear relationship has been reported between pre-operative fibrinogen levels and postoperative blood loss in cardiac surgery. However, recently high pre-operative fibrinogen levels have also been reported to be associated with increased blood transfusion and re-operation.

OBJECTIVE

We tested the hypothesis that the relationship between pre-operative fibrinogen levels and severe peri-operative bleeding is not linear.

DESIGN

A large-scale (n = 3883) single-centre retrospective study.

SETTING

A tertiary care teaching hospital.

PATIENTS

We analysed data from our institutional database which includes all patients above 18 years who underwent on-pump cardiac surgery through a sternotomy between September 2010 and May 2014.

MAIN OUTCOME MEASURES

Peri-operative severe bleeding adapted from the Universal Definition of Peri-operative Bleeding, class 3 or 4. The relationship between pre-operative fibrinogen levels and peri-operative severe bleeding was analysed by binary logistic regression. A cubic B-spline transformation was used to estimate the relationship between pre-operative fibrinogen level associated with excessive peri-operative bleeding.

RESULTS

Severe peri-operative bleeding was observed in 957 (24.6%) patients. An L-shaped relationship was observed between pre-operative fibrinogen levels and 24-h postoperative blood loss. The relationship between pre-operative fibrinogen levels and severe peri-operative bleeding (i.e. Universal Definition of Peri-operative Bleeding class 3 or 4) was U-shaped: the risk of severe peri-operative bleeding bottomed at 3.3 g l when the upward sloping curve started at 5.8 g l with a steeper increase above 8.2 g l.

CONCLUSION

We reported a U-shaped relationship between severe peri-operative bleeding and pre-operative fibrinogen levels. While a low-level of fibrinogen appears to be associated with a high risk of bleeding, a high level does not necessarily protect the patient against such a risk and could even be a risk factor for peri-operative bleeding.

The prophylactic use of fibrinogen concentrate in high-risk cardiac surgery

BACKGROUND

Perioperative blood loss is a major contributor to morbidity and mortality in cardiac surgery. Plasma fibrinogen levels play an essential role in hemostasis and deplete quickly during hemorrhage. The objective of this study was to determine whether prophylactic fibrinogen concentrate administration lowers overall blood product transfusion requirements in high-risk cardiac surgery in patients with low fibrinogen plasma levels.

METHODS

The study was performed in a prospective, randomized, and double-blinded design. The investigation included 62 patients undergoing elective, high-risk cardiac surgery. After weaning from cardiopulmonary bypass and reversal of heparin patients received either fibrinogen concentrate or placebo. The primary outcome variable was overall blood product usage 24 hours after intervention.

RESULTS

The fibrinogen group received numerically fewer total units of blood products than the placebo group, but the difference was not statistically or clinically significant (for groups n = 27; n = 29 and 19 vs 37 units, respectively, P = .908). The overall transfusion rate in both groups was significantly lower than the institutional average suggested (fibrinogen group 26%, placebo group 28%). The fibrinogen group showed significantly higher fibrinogen levels (2.38 vs 1.83 g/L (end of surgery), P < .001; 3.33 vs 2.68 g/L (12 hours after intervention), P = .003) and improved viscoelastic coagulation parameters (FIBTEM MCF, 27 vs 23 mm, P = .022).

CONCLUSION

This randomized, controlled trial demonstrates that point-of-care guided and prophylactic treatment with fibrinogen concentrate does not reduce transfusion of blood products in a setting of unexpectedly low transfusion rate as tested in this cohort, but may improve coagulation parameters in the setting of high-risk cardiac surgery.

Society of Cardiovascular Anesthesiologists Clinical Practice Improvement Advisory for Management of Perioperative Bleeding and Hemostasis in Cardiac Surgery Patients

Bleeding after cardiac surgery is a common and serious complication leading to transfusion of multiple blood products and resulting in increased morbidity and mortality. Despite the publication of numerous guidelines and consensus statements for patient blood management in cardiac surgery, research has revealed that adherence to these guidelines is poor, and as a result, a significant variability in patient transfusion practices among practitioners still remains. In addition, although utilization of point-of-care (POC) coagulation monitors and the use of novel therapeutic strategies for perioperative hemostasis, such as the use of coagulation factor concentrates, have increased significantly over the last decade, they are still not widely available in every institution. Therefore, despite continuous efforts, blood transfusion in cardiac surgery has only modestly declined over the last decade, remaining at ≥50% in high-risk patients. Given these limitations, and in response to new regulatory and legislature requirements, the Society of Cardiovascular Anesthesiologists (SCA) has formed the Blood Conservation in Cardiac Surgery Working Group to organize, summarize, and disseminate the available best-practice knowledge in patient blood management in cardiac surgery. The current publication includes the summary statements and algorithms designed by the working group, after collection and review of the existing guidelines, consensus statements, and recommendations for patient blood management practices in cardiac surgery patients. The overall goal is creating a dynamic resource of easily accessible educational material that will help to increase and improve compliance with the existing evidence-based best practices of patient blood management by cardiac surgery care teams.

Lack of effect of Imrecoxib, an innovative and moderate COX-2 inhibitor, on pharmacokinetics and pharmacodynamics of warfarin in healthy volunteers

Imrecoxib is a registered treatment for osteoarthritis pain symptoms in China. This study aims to assess the effect of imrecoxib on the pharmacodynamics and pharmacokinetics of warfarin. 12 healthy male volunteers with CYP2C9*3 AA and VKORC1 AA genotypes took a 5 mg dose of warfarin both alone and concomitantly with steady-state imrecoxib. Both warfarin alone and concomitantly with imrecoxib have safey and good tolerance across the trial. Following warfarin and imrecoxib co-administration, neither C_max, AUC_0-t and t_1/2 of warfarin enantiomers nor AUC of international normalized ratio (INR) were markedly different from those of warfarin alone. The geometric mean ratios (GMRs) (warfarin + imrecoxib: warfarin alone) of INR_(AUC) was 1 (0.99, 1.01). The GMRs of warfarin AUC_0-∞ (90% confidence interval, CIs) for warfarin + imrecoxib: warfarin alone were 1.12 (1.08, 1.16) for R-warfarin and 1.13 (1.07, 1.18) for S- warfarin. The 90% CIs of the GMRs of AUC_0-∞, C_max and INR _(AUC) were all within a 0.8–1.25 interval. The combination of warfarin and imrecoxib did not impact the pharmacodynamics and pharmacokinetics of single-dose warfarin; therefore, when treating a patient with imrecoxib and warfarin, it is not required to adjust the dosage of warfarin.

Relationship Between Preoperative Plasma Fibrinogen Concentration, Perioperative Bleeding, and Transfusions in Elective Adult Spinal Deformity Correction

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

This study sought to investigate the relationship between preoperative (preop) fibrinogen, bleeding, and transfusion requirements in adult spinal deformity corrections.

SUMMARY OF BACKGROUND DATA

Blood loss after major spinal reconstruction increases the risks and costs of surgery. Preoperative fibrinogen levels may predict intra- and postoperative blood loss.

METHODS

Data were collected from clinic charts and hospital medical records of all 142 of a single surgeon's consecutive adult spine patients undergoing 7 or more levels deformity correction surgeries from January 2011 to December 2014. t tests were used to compare perioperative variables between patients with total blood loss in the upper quartile (≥1,000 mL) and the remaining patients. Similarly, patients receiving >2 units of packed red cells (PRCs) were compared with others. Analysis of variance was used to compare the blood loss between the patients' groups (quartiles) based on their preoperative fibrinogen concentration.

RESULTS

Mean total blood loss was 847.9 (±543.6) mL. Overall, mean preoperative fibrinogen concentration was 254.8 (±82.9) mg/dL. Patients with lower fibrinogen concentration (<193 mg/dL) experienced significantly higher blood loss than those with higher concentrations (p < .05). Patients with transfusion >2 units PRC had significantly greater number of spinal levels treated, higher mean operative time, total blood loss and lower mean preoperative fibrinogen than those transfused 2 or fewer units PRC (p < .05). Total blood loss correlated significantly with preoperative fibrinogen concentration (r = -0.51, p < .05). All the thromboelastography (TEG) variables (G, K, and Angle) correlated significantly with preoperative fibrinogen (p < .05).

CONCLUSIONS

In our cohort undergoing correction of adult spinal deformity, patients with preoperative fibrinogen level lower than 193 mg/dL had significantly higher bleeding than their counterparts. Perioperative transfusion requirements correlated moderately both with the blood loss and preoperative fibrinogen concentration. Incorporation of preoperative fibrinogen allows better prediction of total perioperative blood loss and may therefore guide the treatment team in use of ameliorating therapies.

LEVEL OF EVIDENCE

Level IV.

Can Preoperative C-Reactive Protein Predict Bleeding After On-Pump Coronary Artery Bypass Grafting?

BACKGROUND

Bleeding after cardiac surgery remains a challenge. Numerous studies suggest that higher level of C-reactive protein (CRP) increases cardiovascular risk. There is limited information revealing the association of preoperative CRP concentration and postoperative bleeding while undergoing on-pump coronary artery bypass grafting (CABG). This study aimed to investigate the relationship between preoperative CRP level and postoperative bleeding within 24 hours after CABG.

METHODS

Data on 1055 patients accepting isolated primary CABG at Fuwai Hospital, Chinese Academy of Medical Sciences from September 2017 to July 2018 were recorded. Preoperative CRP concentration, laboratory coagulation parameters, intraoperative data, and postoperative bleeding volume within 24 hours after surgery were recorded. The primary endpoint was bleeding volume within 24 hours after surgery. We analyzed the correlation between bleeding volume within 24 hours after surgery and preoperative data with univariate and multiple linear regression.

RESULTS

Preoperative CRP concentration (B = -0.094, P < .001), platelet count (B = -0.115, P < .01), thrombocytocrit (B = -0.127, P < .001), prothrombin time (B = 0.052, P < .01), and fibrinogen (B = -0.096, P < .01) were univariably correlated with postoperative bleeding volume. However preoperative CRP concentration (B = -0.089, P < .05) was an independent predictor of postoperative bleeding volume after multiple linear regression. Preoperative CRP concentration was also associated with body mass index (B = 0.068, P = .038), activated partial thromboplastin time (B = 0.089, P < .01), and fibrinogen (B = 0.519, P < .01) after multiple linear regression.

CONCLUSIONS

Our findings suggested that preoperative CRP concentration independently correlated with postoperative bleeding volume within 24 hours and that it could be a new potential coagulation biomarker for patients undergoing CABG surgery.

Effects of storage over a 36-month period on coagulation factors in a canine plasma product obtained by use of plasmapheresis

OBJECTIVE

To evaluate stability of coagulation factors in canine plasma obtained by use of plasmapheresis and stored over a 36-month period.

SAMPLE

Canine plasma obtained by use of plasmapheresis acquired from a commercial blood bank.

PROCEDURES

Coagulation testing for fibrinogen concentration and activity of factors II, V, VII, VIII, and IX and von Willebrand factor was performed on canine plasma obtained by use of plasmapheresis. Samples were obtained for testing at 6-month intervals from plasma stored for up to 36 months.

RESULTS

A simple mixed linear regression model was created for each analysis. Median value for the fibrinogen concentration was > 150 mg/dL for all time points, except at 467, 650, and 1,015 days of storage. Median value for factor VIII was > 70% only at 650 days. Median value for factor V was > 50% through 650 days. Median value for factors VII and X was > 50% through 833 days, and median value for factors II and VII was > 50% through 1,015 days. Median value for von Willebrand factor was > 50% for the entire study (1,198 days). Median value for factor X was always < 50%.

CONCLUSIONS AND CLINICAL RELEVANCE

Coagulation factors degraded over time at variable rates, and all labile factors remained at > 50% activity for longer than 1 year. Plasma collected by plasmapheresis potentially offers prolonged life span of some clotting factors. Plasmapheresis is an acceptable form of canine plasma collection for transfusion purposes, and further studies should be performed to determine all of its benefits.

Fibrinogen levels measured by the dry hematology method are lower than those measured by the Clauss method under a high concentration of heparin

The activity of fibrinogen has been reported to decrease soon after the onset of major bleeding and to be an important determinant of the final extent of bleeding and postoperative outcome. A device that measures the perioperative fibrinogen level using the dry hematology (DH) method has recently become available. The aim of this study was to compare perioperative fibrinogen levels measured by the DH method with those measured by the conventional Clauss method and to assess the effects of heparin on these measurements. The study included 206 samples from 36 patients undergoing major surgery who received high-dose heparin (HH group, 23 samples), low-dose heparin (LH group, 57 samples), or no heparin (C group, 126 control samples). Each sample was measured using the DH and Clauss methods. After excluding samples outside the effective measurement range, the three study groups (HH group, n=23; LH group, n=49; C group, n=115) were compared. The mean fibrinogen level measured by the DH method in the HH group (87.9 ± 3.1%) was significantly lower than that measured by the Clauss method. There were no significant differences between the fibrinogen measurements obtained by the two methods between the LH and C groups. In patients on high-dose heparin, the mean fibrinogen level measured by the DH method was significantly lower than that measured by the Clauss method. When hemorrhage requires emergency treatment, a method that can measure the fibrinogen level rapidly is important. The DH method may be useful for decision-making with regard to perioperative coagulation factor replacement.

Haemotherapy with Fibrinogen for Perioperative Bleeding Prevention-A View on Arterial Thrombogenesis and Myocardial Infarction in the Rat In Vivo

Major blood loss during cardiac surgery is associated with increased morbidity and mortality. Clinical pilot studies indicated that preoperative fibrinogen supplementation reduces postoperative blood loss without increasing thrombotic complications. However, an increase in fibrinogen concentration might rather aggravate pre-existing thrombosis than increase the incidence of thrombotic events. Therefore, we investigated, in the present study, whether fibrinogen supplementation influences (1) arterial thrombus formation, (2) the extent of myocardial infarction and (3) the cardioprotective effect of ischaemic preconditioning. Arterial thrombogenesis of the femoral artery was induced by topic FeCl₃ treatment in anaesthetised Wistar rats after pretreatment with 60 mg/kg (Fib_low), 120 mg/kg (Fib_high) or vehicle (Con). Vessel blood flow was monitored, and time to vessel occlusion was analysed as a marker for arterial thrombogenesis. In addition, regional myocardial I/R injury was induced by temporary left coronary artery occlusion in rats pretreated with or without fibrinogen supplementation. In additional groups, ischaemic preconditioning (IPC) was induced by 3 cycles of 5 min of ischaemia/reperfusion. In all groups, myocardial infarct size was determined by triphenyltetrazoliumchlorid staining. Arterial thrombogenesis was not affected by fibrinogen pretreatment. No differences in time until vessel occlusion between Con, Fib_low and Fib_high groups were observed. In addition, fibrinogen supplementation in low and high concentrations had no effect on infarct size after regional myocardial ischaemia and reperfusion (Fib_low: 66 ± 10%, Fib_high: 62 ± 9%; each ns vs. Con). IPC reduced infarct size from 62 ± 14% to 34 ± 12% (p < 0.05 vs. Con). Furthermore, both fibrinogen concentrations did not affect cardioprotection by ischaemic preconditioning (Fib_low + IPC: 34 ± 11%, Fib_high + IPC: 31 ± 13%; each ns vs. IPC). Haemotherapy with fibrinogen did not affect arterial thrombogenesis, myocardial infarction and the cardioprotective effect of ischaemic preconditioning.

A Low-dose human fibrinogen is not effective in decreasing postoperative bleeding and transfusion requirements during cardiac surgery in case of concomitant clinical bleeding and low FIBTEM values: A retrospective matched study

Background

Studies evaluating the hemostatic effects of fibrinogen administration in cardiac surgery are not conclusive.

Aims

We investigated whether the use of a low-dose human fibrinogen in case of clinical bleeding after protamine administration and concomitant low FIBTEM values is effective in reducing postoperative bleeding. Secondary end-point was to investigate the consumption of allogeneic blood products.

Setting and Design

This was a retrospective matched study conducted at university hospital.

Materials and Methods

Among 2257 patients undergoing surgery with cardiopulmonary (CPB) bypass, 73 patients received a median dose of 1 g human fibrinogen (ROTEM-Fibri group). This group was matched with 73 patients who had not received human fibrinogen (control group) among 390 patients having undergone surgery at the moment FIBTEM analysis was unavailable.

Statistical Analysis

Matching was performed for the type and the presence of redo surgery. McNemar and Wilcoxon paired tests were used to respectively compare the categorical and quantitative variables.

Results

The CPB bypass time was significantly higher in the ROTEM-Fibri group (P = 0.006). This group showed significantly higher bleeding in the first 12 and 24 h postoperatively (P < 0.001) and required significantly more transfusion of blood products (P < 0.001) and surgical revision (P = 0.007) when compared with the control group. There was no significant difference in the number of thromboembolic complications.

Conclusions

These results show that the administration of 1 g of fibrinogen based on low-FIBTEM values and clinical bleeding after protamine administration does not stop bleeding and the need for transfusion of allogeneic blood products.

Clinical Impact of Protamine Titration-Based Heparin Neutralization in Patients Undergoing Coronary Bypass Grafting Surgery

OBJECTIVES

A hemostasis management system (HMS) is a point-of-care method for heparin and protamine titration. The authors hypothesized that protamine dosing over the HMS estimate would be associated with elevated activated clotting time (ACT), increased bleeding, and transfusion owing to protamine's anticoagulant activity.

DESIGN

A retrospective cohort study.

SETTING

Single-center university hospital.

PARTICIPANTS

One hundred eighty-nine patients undergoing elective coronary artery bypass grafting surgery.

INTERVENTIONS

Patients were stratified into 3 groups per ratio of actual total administered protamine versus the HMS-derived protamine estimate: (1) low-ratio (≤66% of HMS estimate), (2) moderate-ratio (66%-100% of HMS estimate), and (3) high-ratio (>100% of HMS estimate).

MEASUREMENTS AND MAIN RESULTS

The primary endpoints were post-protamine ACT, and residual heparin levels on HMS among the 3 groups in addition to bleeding and transfusion. There were 54 (28.6%) patients in the low, 95 (50.3%) in the moderate, and 40 (21.2%) in the high-ratio group. The high-ratio patients who were overdosed with protamine relative to the HMS estimate had elevated ACT, international normalized ratio, and activated partial thromboplastin time values, and subsequently received more red blood cell (RBC) and non-RBC transfusions compared to lower-ratio groups. Higher actual/HMS protamine ratios were associated independently with post-protamine ACT elevations after adjustment for sex, body mass index (BMI), and cardiopulmonary bypass (CPB) time.

CONCLUSION

Most patients received the protamine dose sufficiently close to the HMS estimate, but protamine dosing above the HMS estimate occurred in both obese and nonobese patients, which was associated independently with prolonged ACT after adjusting for sex, BMI, and CPB time.

Rotational Thromboelastometry for Assessing Bleeding Complications and Factor XIII Deficiency in Cardiac Surgery Patients

We aimed to detect alterations and deficits in hemostasis during cardiac surgery with cardiopulmonary bypass (CPB) using point-of-care-supported coagulation analysis (rotational thromboelastometry, impedance aggregometry), in addition to single factor assays for the measurement of fibrinogen (FI) and factor XIII (FXIII) levels. Forty-one patients scheduled for elective cardiac surgery with CPB were enrolled in this observational study. Perioperative measurement (pre-, postheparin, 30-minutes before the end of bypass, 1-hourpostoperatively) of standard laboratory variables, additional rotational thromboelastometry (ROTEM; International GmbH, Munich, Germany), Multiplate analysis (Roche, Switzerland), and an assay of FXIII activity were performed as well as the collection of epidemiological data and blood loss. The FI and FXIII levels as well as the measured ROTEM and Multiplate parameters correlated weakly with the blood loss. Clotting time and maximum clot firmness (MCF) of the intrinsically activated ROTEM showed a good correlation (r_CT-INTEM = 0.378; P < .05, r_MCF-INTEM = 0.305; P < .05) with postoperative drainage loss, suggesting a dependence of blood loss on the initial intrinsic activity. Additionally, perioperative FI or FIBTEM levels and the FXIII levels correlated with each other. Intrinsically activated ROTEM showed a good correlation with postoperative drainage loss, thus suggesting a dependence of blood loss on the initial intrinsic activity and therefore facilitating clinicians to assess postoperative bleeding complications. Based on the FI level or the MCF_FIBTEM measured by ROTEM, it may also be possible to assess the FXIII concentration. Especially in chronically ill and massive bleeding cardiac surgery patients with significantly decreased FXIII levels, the knowledge of FXIII deficiency may help clinicians to treat coagulation disorders more adequately.

Randomized evaluation of fibrinogen vs placebo in complex cardiovascular surgery (REPLACE): a double-blind phase III study of haemostatic therapy

BACKGROUND

Single-dose human fibrinogen concentrate (FCH) might have haemostatic benefits in complex cardiovascular surgery.

METHODS

Patients undergoing elective aortic surgery requiring cardiopulmonary bypass were randomly assigned to receive FCH or placebo. Study medication was administered to patients with a 5 min bleeding mass of 60-250 g after separation from bypass and surgical haemostasis. A standardized algorithm for allogeneic blood product transfusion was followed if bleeding continued after study medication.

RESULTS

519 patients from 34 centres were randomized, of whom 152 (29%) met inclusion criteria for study medication. Median (IQR) pretreatment 5 min bleeding mass was 107 (76-138) and 91 (71-112) g in the FCH and placebo groups, respectively (P=0.13). More allogeneic blood product units were administered during the first 24 h after FCH, 5.0 (2.0-11.0), when compared with placebo, 3.0 (0.0-7.0), P=0.026. Fewer patients avoided transfusion in the FCH group (15.4%) compared with placebo (28.4%), P=0.047. The FCH immediately increased plasma fibrinogen concentration and fibrin-based clot strength. Adverse event rates were comparable in each group.

CONCLUSIONS

Human fibrinogen concentrate was associated with increased allogeneic blood product transfusion, an unexpected finding contrary to previous studies. Human fibrinogen concentrate may not be effective in this setting when administered according to 5-minute bleeding mass. Low bleeding rates and normal-range plasma fibrinogen concentrations before study medication, and variability in adherence to the complex transfusion algorithm, may have contributed to these results.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier no. NCT01475669; EudraCT trial no. 2011-002685-20.

Perioperative management of the bleeding patient

Perioperative bleeding remains a major complication during and after surgery, resulting in increased morbidity and mortality. The principal causes of non-vascular sources of haemostatic perioperative bleeding are a preexisting undetected bleeding disorder, the nature of the operation itself, or acquired coagulation abnormalities secondary to haemorrhage, haemodilution, or haemostatic factor consumption. In the bleeding patient, standard therapeutic approaches include allogeneic blood product administration, concomitant pharmacologic agents, and increasing application of purified and recombinant haemostatic factors. Multiple haemostatic changes occur perioperatively after trauma and complex surgical procedures including cardiac surgery and liver transplantation. Novel strategies for both prophylaxis and therapy of perioperative bleeding include tranexamic acid, desmopressin, fibrinogen and prothrombin complex concentrates. Point-of-care patient testing using thromboelastography, rotational thromboelastometry, and platelet function assays has allowed for more detailed assessment of specific targeted therapy for haemostasis. Strategic multimodal management is needed to improve management, reduce allogeneic blood product administration, and minimize associated risks related to transfusion.

Effect of Local Fibrinogen Administration on Postoperative Bleeding in Open Prostatectomy Surgery

Background

Open prostatectomy is still accompanied by some postoperative bleeding. Prescribing fibrinogen to promote clot formation in patients with bleeding is of critical importance. This research studied the effects of local injection of fibrinogen on level of postoperative bleeding in open prostatectomy.

Methods

Overall, 44 patients were randomly entered in a study on open prostatectomy. Patients in the intervention group received local injections of 500 mg fibrinogen (20 mL) dissolved in distilled water, and the control group patients only received 20 mL of normal saline, where the injections were given by the surgeon at the prostatectomy operation site. All patients were tested for hemoglobin, hematocrit, PT, PTT, INR, and fibrinogen level. Also, the amount of blood loss and requirement for blood products were recorded.

Results

The study groups showed no difference regarding baseline variables. One patient in the fibrinogen group (1.66%) and four patients in the control group (6.66%) received blood products (P < 0.05), and the blood drainage tube at 24 hours after operation was 36.50) 18.70 (mL in the fibrinogen group and 151.36) 120.58 (mL in the control group (P = 0.005). There were no differences in hemoglobin, hematocrit, PT, PTT, INR, and serum fibrinogen level between the groups at any time.

Conclusions

The current study demonstrated that using fibrinogen in patients with high bleeding risk may effectively reduce the amount of bleeding and its subsequent blood transfusion requirement, after open prostatectomy surgery.

Protocol for a phase III, non-inferiority, randomised comparison of a new fibrinogen concentrate versus cryoprecipitate for treating acquired hypofibrinogenaemia in bleeding cardiac surgical patients: the FIBRES trial

INTRODUCTION

Coagulopathic bleeding is a serious complication of cardiac surgery to which an important contributor is acquired hypofibrinogenaemia (plasma fibrinogen <1.5-2.0 g/L). The standard intervention for acquired hypofibrinogenaemia is cryoprecipitate, but purified fibrinogen concentrates are also available. There is little comparative data between the two therapies and randomised trials are needed.

METHODS AND ANALYSIS

FIBrinogen REplenishment in Surgery (FIBRES) is a multicentre, randomised (1:1), active-control, single-blinded, phase III trial in adult cardiac surgical patients experiencing clinically significant bleeding related to acquired hypofibrinogenaemia. The primary objective is to demonstrate that fibrinogen concentrate (Octafibrin/Fibryga; Octapharma) is non-inferior to cryoprecipitate. All patients for whom fibrinogen supplementation is ordered by the clinical team within 24 hours of cardiopulmonary bypass will receive 4 g of fibrinogen concentrate or 10 units of cryoprecipitate (dose-equivalent to 4 g), based on random allocation and deferred consent. The primary outcome is total red cell, platelet and plasma transfusions administered within 24 hours of bypass. Secondary outcomes include major bleeding, fibrinogen levels and adverse events within 28 days. Enrolment of 1200 patients will provide >90% power to demonstrate non-inferiority. One preplanned interim analysis will include 600 patients. The pragmatic design and treatment algorithm align with standard practice, aiding adherence and generalisability.

ETHICS AND DISSEMINATION

The study is approved by the local research ethics board and will be conducted in accordance with the Declaration of Helsinki, Good Clinical Practice guidelines and regulatory requirements. Patient consent prior to treatment is waived, as per criteria in the Tri-Council Policy Statement. Results will be published in the scientific/medical literature, and at international congresses. Non-inferiority of purified fibrinogen concentrate would support its use in acquired hypofibrinogenaemia. The results are likely to improve care for cardiac surgical patients experiencing significant bleeding, an understudied yet high-risk population.

TRIAL REGISTRATION NUMBER

NCT03037424; Pre-results.

The role of fibrinogen in trauma-induced coagulopathy

Fibrinogen plays an essential role in clot formation and stability. Importantly it seems to be the most vulnerable coagulation factor, reaching critical levels earlier than the others during the course of severe injury. A variety of causes of fibrinogen depletion in major trauma have been identified, such as blood loss, dilution, consumption, hyperfibrinolysis, hypothermia and acidosis. Low concentrations of fibrinogen are associated with an increased risk of diffuse microvascular bleeding. Therefore, repeated measurements of plasma fibrinogen concentration are strongly recommended in trauma patients with major bleeding. Recent guidelines recommend maintaining plasma fibrinogen concentration at 1.5–2 g/l in coagulopathic patients. It has been shown that early fibrinogen substitution is associated with improved outcome.