Plasma fibrinogen level on admission to the intensive care unit is a powerful predictor of postoperative bleeding after cardiac surgery with cardiopulmonary bypass

High-Dose TXA Is Associated with Less Blood Loss Than Low-Dose TXA without Increased Complications in Patients with Complex Adult Spinal Deformity

BACKGROUND

Tranexamic acid (TXA) is commonly utilized to reduce blood loss in adult spinal deformity (ASD) surgery. Despite its widespread use, there is a lack of consensus regarding the optimal dosing regimen. The aim of this study was to assess differences in blood loss and complications between high, medium, and low-dose TXA regimens among patients undergoing surgery for complex ASD.

METHODS

A multicenter database was retrospectively analyzed to identify 265 patients with complex ASD. Patients were separated into 3 groups by TXA regimen: (1) low dose (<20-mg/kg loading dose with ≤2-mg/kg/hr maintenance dose), (2) medium dose (20 to 50-mg/kg loading dose with 2 to 5-mg/kg/hr maintenance dose), and (3) high dose (>50-mg/kg loading dose with ≥5-mg/kg/hr maintenance dose). The measured outcomes included blood loss, complications, and red blood cell (RBC) units transfused intraoperatively and perioperatively. The multivariable analysis controlled for TXA dosing regimen, levels fused, operating room time, preoperative hemoglobin, 3-column osteotomy, and posterior interbody fusion.

RESULTS

The cohort was predominantly White (91.3%) and female (69.1%) and had a mean age of 61.6 years. Of the 265 patients, 54 (20.4%) received low-dose, 131 (49.4%) received medium-dose, and 80 (30.2%) received high-dose TXA. The median blood loss was 1,200 mL (interquartile range [IQR], 750 to 2,000). The median RBC units transfused intraoperatively was 1.0 (IQR, 0.0 to 2.0), and the median RBC units transfused perioperatively was 2.0 (IQR, 1.0 to 4.0). Compared with the high-dose group, the low-dose group had increased blood loss (by 513.0 mL; p = 0.022) as well as increased RBC units transfused intraoperatively (by 0.6 units; p < 0.001) and perioperatively (by 0.3 units; p = 0.024). The medium-dose group had increased blood loss (by 491.8 mL; p = 0.006) as well as increased RBC units transfused intraoperatively (by 0.7 units; p < 0.001) and perioperatively (by 0.5 units; p < 0.001) compared with the high-dose group.

CONCLUSIONS

Patients with ASD who received high-dose intraoperative TXA had fewer RBC transfusions intraoperatively, fewer RBC transfusions perioperatively, and less blood loss than those who received low or medium-dose TXA, with no differences in the rates of seizure or thromboembolic complications.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Heat stress-induced platelet dysfunction is associated with loss of fibrinogen and is improved by fibrinogen supplementation

INTRODUCTION

Heatstroke is a critical heat-related condition characterized by coagulopathy and multiple organ dysfunction. One of the most severe complications of heatstroke is disseminated intravascular coagulation. This condition manifests as excessive clot formation and bleeding that are primarily due to platelet depletion and dysfunction. Fibrinogen plays a crucial role in hemostasis because it links integrin αIIbβ3 on adjacent platelets, thereby promoting the platelet activation and aggregation necessary for clot formation. However, reduced fibrinogen levels may impair the formation of the initial platelet plug and increase the risk of bleeding. The current study explored the effect of fibrinogen on platelet dysfunction in a heatstroke model.

MATERIALS AND METHODS

Male Wistar rats were subjected to heat stress, and subsequent changes in hemodynamic, biochemical, and coagulation parameters were analyzed. Platelet viability, aggregation, adhesion, spreading and fibrin clot retraction were assessed.

RESULTS

The rats with heatstroke exhibited a variety of clinical symptoms, including hypotension, tachycardia, multiple organ dysfunction, and coagulopathy. Platelet viability in the heatstroke group was comparable to that in the healthy control group. However, the heatstroke group exhibited significant reductions in plasma fibrinogen levels and platelet aggregation, adhesion, spreading, and fibrin clot retraction. Notably, fibrinogen supplementation markedly augmented the aggregation responses of platelets in the heatstroke group. The impairment of platelet adhesion, spreading, and fibrin clot retraction in the rats with heatstroke was partially ameliorated by fibrinogen supplementation.

CONCLUSIONS

An early use of fibrinogen replacement may serve as a therapeutic intervention to alleviate platelet hyporeactivity and prevent the complications in patients with heatstroke.

Cardiac Surgical Bleeding, Transfusion, and Quality Metrics: Joint Consensus Statement by the Enhanced Recovery After Surgery Cardiac Society and Society for the Advancement of Patient Blood Management

BACKGROUND

Excessive perioperative bleeding is associated with major complications in cardiac surgery, resulting in increased morbidity, mortality, and cost.

METHODS

An international expert panel was convened to develop consensus statements on the control of bleeding and management of transfusion and to suggest key quality metrics for cardiac surgical bleeding. The panel reviewed relevant literature from the previous 10 years and used a modified RAND Delphi methodology to achieve consensus.

RESULTS

The panel developed 30 consensus statements in 8 categories, including prioritizing control of bleeding, prechest closure checklists, and the need for additional quality indicators beyond reexploration rate, such as time to reexploration. Consensus was also reached on the need for a universal definition of excessive bleeding, the use of antifibrinolytics, optimal cessation of antithrombotic agents, and preoperative risk scoring based on patient and procedural factors to identify those at greatest risk of excessive bleeding. Furthermore, an objective bleeding scale is needed based on the volume and rapidity of blood loss accompanied by viscoelastic management algorithms and standardized, patient-centered blood management strategies reflecting an interdisciplinary approach to quality improvement.

CONCLUSIONS

Prioritizing the timely control and management of bleeding is essential to improving patient outcomes in cardiac surgery. To this end, a cardiac surgical bleeding quality metric that is more comprehensive than reexploration rate alone is needed. Similarly, interdisciplinary quality initiatives that seek to implement enhanced quality indicators will likely lead to improved patient care and outcomes.

Evaluation of Point-of-Care-Directed Coagulation Management in Pediatric Cardiac Surgery

BACKGROUND

 Coagulatory alterations are common after pediatric cardiac surgery and can be addressed with point-of-care (POC) coagulation analysis. The aim of the present study is to evaluate a preventive POC-controlled coagulation algorithm in pediatric cardiac surgery.

METHODS

 This single-center, retrospective data analysis included patients younger than 18 years who underwent cardiac surgery with cardiopulmonary bypass (CPB) and received a coagulation therapy according to a predefined POC-controlled coagulation algorithm. Patients were divided into two groups (<10 and >10 kg body weight) because of different CPB priming strategies.

RESULTS

 In total, 173 surgeries with the use of the POC-guided hemostatic therapy were analyzed. In 71% of cases, target parameters were achieved and only in one case primary sternal closure was not possible. Children with a body weight ≤10 kg underwent surgical re-evaluation in 13.2% (15/113), and respectively 6.7% (4/60) in patients >10 kg. Hemorrhage in children ≤10 kg was associated with cyanotic heart defects, deeper intraoperative hypothermia, longer duration of CPB, more complex procedures (RACHS-1 score), and with more intraoperative platelets, and respectively red blood cell concentrate transfusions (all p-values < 0.05). In children ≤10 kg, fibrinogen levels were significantly lower over the 12-hour postoperative period (without revision: 3.1 [2.9-3.3] vs. with revision 2.8 [2.3-3.4]). Hemorrhage in children >10 kg was associated with a longer duration of CPB (p = 0.042), lower preoperative platelets (p = 0.026), and over the 12-hour postoperative period lower platelets (p = 0.002) and fibrinogen (p = 0.05).

CONCLUSION

 The use of a preventive, algorithm-based coagulation therapy with factor concentrates after CPB followed by POC created intraoperative clinical stable coagulation status with a subsequent executable thorax closure, although the presented algorithm in its current form is not superior in the reduction of the re-exploration rate compared to equivalent collectives. Reduced fibrinogen concentrations 12 hours after surgery may be associated with an increased incidence of surgical revisions.

The differences of fibrinogen levels in various types of hemorrhagic transformations

Introduction

Hemorrhagic transformation (HT) is a serious complication that can occur spontaneously after an acute ischemic stroke (AIS) or after a thrombolytic/mechanical thrombectomy. Our study aims to explore the potential correlations between fibrinogen levels and the occurrence of spontaneous HT (sHT) and HT after mechanical thrombectomy (tHT).

Methods

A total of 423 consecutive AIS patients diagnosed HT who did not undergone thrombolysis and 423 age- and sex-matched patients without HT (non-HT) were enrolled. Fibrinogen levels were measured within 24 h of admission after stroke. The cohorts were trisected according to fibrinogen levels. The HT were further categorized into hemorrhagic infarction (HI) or parenchymal hematoma (PH) based on their imaging characteristics.

Results

In sHT cohort, fibrinogen levels were higher in HT patients than non-HT patients (p < 0.001 versus p = 0.002). High fibrinogen levels were associated with the severity of HT. HT patients without atrial fibrillation (AF) had higher levels of fibrinogen compared to non-HT (median 3.805 vs. 3.160, p < 0.001). This relationship did not differ among AF patients. In tHT cohort, fibrinogen levels were lower in HT patients than non-HT patients (p = 0.002). Lower fibrinogen levels were associated with the severity of HT (p = 0.004). The highest trisection of fibrinogen both in two cohorts were associated with HT [sHT cohort: OR = 2.515 (1.339-4.725), p = 0.016; that cohort: OR = 0.238 (0.108-0.523), p = 0.003].

Conclusion

Our study suggests that lower fibrinogen level in sHT without AF and higher fibrinogen level in tHT are associated with more severe HT.

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.

Evaluation of fibrinogen concentration by clot firmness using a dielectric blood coagulation test system

PURPOSE

To determine if fibrinogen concentration can be evaluated by dielectric permittivity changes in dielectric blood coagulation testing (DBCM) during cardiovascular surgery with cardiopulmonary bypass (CPB).

METHODS

We performed a single-center prospective observational study at a university hospital. One hundred patients undergoing cardiovascular surgery with CPB were enrolled. Whole-blood samples were obtained after weaning from CPB, and dielectric clot strength (DCS) was measured by intrinsic pathway testing with or without heparinase in DBCM. The FIBTEM test was performed during rotational thromboelastometry using the same samples, and maximum clot firmness (MCF) was evaluated. Spearman's correlation analysis was performed, and receiver operating characteristics (ROC) curve analyses were used to evaluate the performance of hypofibrinogenemia detection.

RESULTS

DCS showed a strong positive correlation with plasma fibrinogen concentration (Rs = 0.76, P < 0.0001). The area under the ROC curve for evaluating plasma fibrinogen concentration < 200 mg/dL was 0.91 (95% confidence interval (CI) 0.85-0.97) for DCS, compared with 0.88 (95% CI 0.81-0.94) for FIBTEM MCF. The optimal cutoff value of DCS was 17.0 (sensitivity 94%, specificity 80%).

CONCLUSIONS

DCS variables showed a significantly strong correlation with plasma fibrinogen concentration, and the diagnostic performance for hypofibrinogenemia was comparable to that for FIBTEM MCF. This novel methodology has the potential to provide a point-of-care test with sufficient accuracy for the detection of perioperative hypofibrinogenemia during cardiovascular surgery with CPB.

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.

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 and Bleeding in Adult Cardiac Surgery: A Review of the Literature

Background: Fibrinogen is a substrate for blood clots formation. In cardiac surgery, a number of different mechanisms lead to a decrease in fibrinogen levels and consequent impaired haemostasis. Patients undergoing cardiac surgery are therefore frequently exposed to blood loss and allogeneic blood transfusion, which are risk factors associated with morbidity and mortality. Thus, particular efforts in fibrinogen management should be made to decrease bleeding and the need for blood transfusion. Therefore, fibrinogen remains an active focus of investigations from basic science to clinical practice. This review aims to summarise the latest evidence regarding the role of fibrinogen and current practices in fibrinogen management in adult cardiac surgery. Methods: The PubMed database was systematically searched for literature investigating the role and disorders of fibrinogen in cardiac surgery and diagnostic and therapeutic procedures related to fibrinogen deficiency aimed at reducing blood loss and transfusion requirements. Clinical trials and reviews from the last 10 years were included. Results: In total, 146 articles were analysed. Conclusion: The early diagnosis and treatment of fibrinogen deficiency is crucial in maintaining haemostasis in bleeding patients. Further studies are needed to better understand the association between fibrinogen levels, bleeding, and fibrinogen supplementation and their impacts on patient outcomes in different clinical settings.

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.

Trigger and Target for Fibrinogen Supplementation Using Thromboelastometry (ROTEM) in Patients Undergoing Open Thoraco-Abdominal Aortic Aneurysm Repair

OBJECTIVE

To determine the relationship between the value of fibrinogen assessed by the FIBTEM clot amplitude at 10 minutes (A10 FIBTEM) measured on admission to the intensive care unit (ICU) and the amount of drainage output at 24 hours, to investigate whether the A10 FIBTEM predicts severe bleeding (SB), and to define A10 FIBTEM thresholds to prevent (trigger) and treat (target) severe bleeding by fibrinogen supplementation.

METHODS

In a single centre, retrospective observational study, 166 patients underwent elective open thoraco-abdominal aortic aneurysm (TAAA) repair between March 2016 and January 2019. Exclusion criteria were emergency, congenital, or acquired coagulopathy, or administration of P₂Y₁₂ inhibitor antiplatelet agents in the five days before surgery. All patients were managed intra-operatively and post-operatively according to a rotational thromboelastometry driven transfusion protocol. The principal endpoint was a composite outcome, which included bleeding, large volume transfusion, and re-operation.

RESULTS

FIBTEM clot amplitude after 10 minutes measured on ICU admission and post-operative bleeding at 24 hours showed an inverse linear relationship (R² = .03; p = .026). Performance of A10 FIBTEM in predicting SB evaluated by Receiving Operating Curve analysis showed an area under the curve of 0.63 (95% CI 0.56 - 0.70; p = .026) with a best cutoff of 9 mm. An A10 FIBTEM of 3 mm was the cutoff associated with a positive predictive value of 50%, while an A10 FIBTEM of 9 mm showed a negative predictive value of 92%. On multivariable analysis, an A10 FIBTEM ≤ 3 mm remained independently associated with SB.

CONCLUSION

The present investigation shows for the first time in a population undergoing open TAAA repair that an A10 FIBTEM ≤ 3mm on ICU admission is associated with post-operative severe bleeding. Trigger and target values for fibrinogen supplementation, based on A10 FIBTEM, have been provided. The transferability and reliability of these cutoff values require further study.

Fibrin clot susceptibility to lysis is impaired after on-pump coronary artery by-pass grafting with tranexamic acid: clinical implications

Coronary artery bypass grafting (CABG) done on-pump may cause a significant blood loss. Low fibrinogen is associated with perioperative bleeding. The influence of cardiopulmonary bypass on fibrin clot properties is poorly investigated. We studied 55 patients with isolated coronary artery disease on aspirin undergoing on-pump CABG with tranexamic acid. Fibrinogen levels, fibrinolytic capacity expressed as clot lysis time (CLT), thrombin generation potential and platelet count were assessed before and after the surgery (prior to admission to the intensive care unit). A postoperative drop in haemoglobin (-30% from baseline), haematocrit (-31% from baseline) and platelet count (-42% from baseline) was observed (all, P < 0.0001). Postoperative fibrinogen level was lower by 57%, compared with preoperative value (1.5 [1.3-1.8] vs. 3.5 [2.8-3.9] g/l, P < 0.0001). Postoperative CLT was longer by 48 min, compared with preoperative (182 [170-218] vs. 134 [122-165] min, P < 0.0001). Thrombin generation was impaired postoperatively: both lag time and time to peak thrombin were prolonged by 44 and 45%, respectively, whereas endogenous thrombin potential and peak thrombin generation decreased by 45 and 78%, respectively (all P < 0.0001). Median postoperative drainage at 12 h was 400 [290-570] ml. Predictors of blood loss at 12 h identified in multivariable linear regression model adjusted for sex and preoperative fibrinogen level were: BMI (b = -23.4, P = 0.048) and postoperative CLT (b = -2.4, P = 0.042). Despite decreased fibrinogen levels after on-pump CABG with tranexamic acid, fibrin clot susceptibility to lysis is impaired, as reflected by prolonged CLT. Postoperative CLT is associated with mediastinal drainage at 12 h.

Detection of hypofibrinogenemia during cardiac surgery: a comparison of resonance-based thrombelastography with the traditional Clauss method

: Bleeding after cardiac surgery is associated with significant morbidity and mortality. Hypofibrinogenemia is a crucial factor for bleeding in this setting and may be rapidly detected using point-of-care viscoelastic tests (POC-VET). However, the correlation of POC-VET with conventional coagulation assays is still unclear. The current study aimed to correlate resonance-based POC-VET assays (Haemonetics TEG 6s) with the traditional nonrapid Clauss method. Another aim was to identify a cut-off value for the detection of hypofibrinogenemia (fibrinogen plasma level below 150 mg/dl) focusing on the maximum amplitude of the TEG 6s citrated functional fibrinogen (CFF) assay. Adult patients undergoing cardiac surgery were screened for inclusion in this single-centre retrospective cohort study. Inclusion criteria were the availability of a TEG assay and timely corresponding laboratory results. Calculation of a CFF-maximum amplitude (CFF-MA) cut-off value was performed using receiver operating curve analysis in the baseline cohort and validated in the control cohort. The best correlation with the Clauss method was observed for the CFF-MA (r = 0.77; P < 0.0001) compared with the citrate kaolin maximum amplitude assay (r = 0.57; P < 0.0001) and the citrate kaolin heparinase maximum amplitude assay (r = 0.67; P < 0.0001). A cut-off value of 19.9 mm for the CFF-MA was calculated [area under the curve 0.87 (95% confidence interval: 0.82-0.92; P < 0.0001)]. This cut-off value had a sensitivity of 81.8% and a specificity of 71.1% for identification of hypofibrinogenemia in the control cohort. The resonance-based thrombelastography analyser can identify hypofibrinogenemia. Future clinical studies should investigate whether cut-off value guided coagulation therapy with POC-VET may improve patient outcomes in patients who suffer from bleeding complications.

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.

The velocity curve of the clotting waveform of rotational thromboelastometry predicts bleeding after cardiac surgery but conventional rotational thromboelastometric parameters do not

BACKGROUND

Early detection of a risk of postoperative bleeding is essential in cardiac surgery patients. The aim of the present study was to evaluate the utility of the first derivative curve (the V-curve) of the clotting waveform of rotational thromboelastometry (ROTEM) in terms of predicting bleeding after cardiac surgery.

METHODS

We retrospectively analysed 534 cardiac surgery patients. We used the chest tube output during the stay in the intensive care unit to divide patients into a higher blood loss group (HBL group; the fourth quartile) and a lower blood loss group (LBL group; the lower quartiles). We performed multivariable logistic regression using the V-curve parameters and potential confounders including conventional ROTEM parameters.

RESULTS

In the multivariable model, the adjusted odds ratios for HBL of patients with a lower maximum clotting velocity (MaxVel ≤9 mm*100 s-1) as revealed by extrinsically activated ROTEM (EXTEM), and the area under the velocity curve (AUC ≤988 mm*100) of the fibrin-based extrinsically activated ROTEM (FIBTEM), both measured at skin closure in the end of surgery, were 1.78 (95% CI 1.03 to 3.07) and 2.14 (95% CI 1.20 to 3.82), respectively. However, conventional ROTEM parameters were not included in the final model. Additionally, lower EXTEM MaxVel and FIBTEM AUC values were associated with the need for a higher transfusion volume, longer postoperative intensive care unit and hospital stays, and more frequent re-exploration to control bleeding.

CONCLUSIONS

The ROTEM V-curve parameters can predict postoperative bleeding and clinical outcomes after cardiac surgery.

Factors associated with the increased bleeding in the postoperative period of cardiac surgery: A cohort study

AIMS AND OBJECTIVES

To identify factors associated with the increased bleeding in patients during the postoperative period after cardiac surgery.

BACKGROUND

Bleeding is among the most frequent complications that occur in the postoperative period after cardiac surgery, representing one of the major factors in morbidity and mortality. Understanding the factors associated with the increased bleeding may allow nurses to anticipate and prioritise care, thus reducing the mortality associated with this complication.

DESIGN

Prospective cohort study.

METHODS

Adult patients in a cardiac hospital who were in the postoperative period following cardiac surgery were included. Factors associated with the increased bleeding were investigated by means of linear regression, considering time intervals of 6 and 12 hr.

RESULTS

The sample comprised 391 participants. The factors associated with the increased bleeding in the first 6 hr were male sex, body mass index, cardiopulmonary bypass duration, anoxia duration, metabolic acidosis, higher heart rate, platelets and the activated partial thromboplastin time in the postoperative period. Predictors in the first 12 hr were body mass index, cardiopulmonary bypass duration, metabolic acidosis, higher heart rate, platelets and the activated partial thromboplastin time in the postoperative.

CONCLUSIONS

This study identified factors associated with the increased postoperative bleeding from cardiac surgery that have not been reported in previous studies. The nurse is important in the vigilance, evaluation and registry of chest tube drainage and modifiable factors associated with the increased bleeding, such as metabolic acidosis and postoperative heart rate, and in discussions with the multiprofessional team.

RELEVANCE TO CLINICAL PRACTICE

Knowledge of the factors associated with the increased bleeding is critical for nurses so they can provide prophylactic interventions and early postoperative treatment when needed.

Identifying optimal heparin management during cardiopulmonary bypass in obese patients: A prospective observational comparative study

BACKGROUND

The heparin regimen providing anticoagulation during cardiopulmonary bypass (CPB) is usually adapted to total body weight (TBW), but may be inaccurate in obese patients in whom TBW exceeds their ideal body weight.

OBJECTIVES

The objective is to compare the effects of heparin injection based on TBW on haemostatic parameters between obese and nonobese patients during cardiac surgery and to calculate the optimal heparin regimen.

DESIGN

Prospective comparative study.

SETTING

University hospital.

PATIENTS

Two groups of 50 patients (BMI≥ or <30 kg m) were included in the study over a 9-month period in 2013. The study started on 27 February 2013.

INTERVENTIONS

An unfractionated heparin (UFH) bolus of 300 IU kg TBW was injected before initiation of CPB followed by additional doses (50 to 100 IU kg) to maintain a target activated coagulation time (ACT) of at least 400 s.

MAIN OUTCOME MEASURES

ACT and plasma heparin concentration were measured at different time points after initiation of, and weaning from CPB.

RESULTS

Obese patients received higher initial and total doses of heparin (P < 0.0001). Plasma heparin concentrations were significantly higher in obese patients at each time point (P < 0.001) and reached very high values after the initial bolus (5.90 vs. 4.48 IU ml, P < 0.0001). The relationship between plasma heparin concentration and ACT after the initial bolus was not linear and followed an asymptotic regression curve. Haemoglobin concentration decreased intraoperatively to a greater extent in the obese group (P < 0.001). No significant differences in postoperative bleeding or global transfusion requirements were observed.

CONCLUSION

The standard heparin regimen based on TBW in obese patients during CPB results in excessive plasma heparin concentrations and a significant intraoperative decrease in haemoglobin concentration. ACT monitoring was not accurate in identifying this excess dosage. An initial bolus of 340 IU kg ideal body weight would achieve a heparin concentration of 4.5 IU ml, similar to that observed in nonobese patients. Further investigations are warranted to confirm this heparin regimen.

Prophylactic Fibrinogen Decreases Postoperative Bleeding but Not Acute Kidney Injury in Patients Undergoing Heart Transplantation

The present study is the premier clinical attempt to scrutinize the practicability of prophylactic fibrinogen infusion in patients undergoing heart transplantation (HT). A total of 67 consecutive patients who had undergone HT between January 2012 and December 2014 were assessed. After exclusion of some patients, 23 patients were given preoperative 2 g fibrinogen concentrate over a period of 15 minutes after the termination of cardiopulmonary bypass pump and complete reversal of heparin, and 30 patients were not given. Some laboratories were measured before general anesthesia and at 6 and 24 hours after surgery. In addition, major adverse events were also evaluated during hospitalization. The mean age of the patients was 39.5 ± 11.4 years, with a predominance of male sex (77.4%). All laboratories at baseline were comparable between groups. The length of hospital stay was longer in the control group compared to the fibrinogen group (20 [16-22] vs 16 [12-19] days; P = .005). There was a trend for patients in the fibrinogen group to have more acute kidney injury (AKI) after surgery (10% vs 30.4%) and less reoperation for bleeding (20% vs 8.7%). The amount of postoperative bleeding was significantly higher in the control group compared to the fibrinogen group (P < .001). The number of packed red blood cell transfused during 24 hours after surgery was significantly lower in the fibrinogen group (P < .001). The transfusion of fibrinogen in patients undergoing HT may be associated with reductions in postoperative bleeding, the number of packed red blood cells, and hospital length of stay; however, it may enhance postoperative AKI.

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.

Insufficient fibrinogen response following free flap surgery is associated with bleeding complications

Background: Microvascular tissue transfer has become a safe and reliable tool in the reconstructive armamentarium, yielding high success rates. However, little is known about the changes in coagulation after free tissue transfer and their potential impact on morbidity. Methods: Fibrinogen concentration and platelet count among other values were available and assessed in 139 undergoing free tissue transfer before, immediately after, and 1-3 as well as 8-11 days after surgery. In patients undergoing urgent revision for either bleeding or microvascular thrombosis, blood samples were drawn directly before re-exploration. Results: In the patients without any surgical revision and in those with thrombosis of the microvascular pedicle, both fibrinogen concentration and platelet count increased significantly during the early and late post-operative window. Patients that developed bleeding necessitating re-exploration showed an inadequate increase in fibrinogen levels, resulting in significantly lower concentrations compared to the other two groups. There were no significant differences in platelet count or PTT between these groups. Conclusion: Free flap surgery induces acute and subacute changes in coagulation, comparable to other major surgeries and severe injuries. This leads to an increase in platelet count and fibrinogen over the post-operative course. Patients that developed bleeding requiring surgical re-exploration showed an insufficient increase in fibrinogen, resulting in significantly lower fibrinogen levels. Therefore, monitoring and correction of fibrinogen levels might aid in preventing or treating bleeding complications following free flap surgery.

Trends in isolated coronary artery bypass grafting over the last decade

OBJECTIVES

The purpose of this study was to assess the impact on hospital mortality and morbidity of extensive myocardial revascularization, using arterial grafts in patients undergoing isolated coronary artery bypass grafting (CABG).

METHODS

Our prospective perioperative database was used to define two groups of patients who underwent isolated CABG with cardiopulmonary bypass, based on the years in which the operation was performed: Group A (2000-2003; 898 patients) and Group B (2009-2012; 1249 patients). The baseline and operative characteristics and outcomes were compared.

RESULTS

Several significant changes in perioperative variables were observed. Group B included higher percentages of patients aged over 80 years (+58.1%), with diabetes (+32.0%) and with a history of percutaneous coronary intervention (+24.9%). The mean EuroSCORE II was significantly increased from 2.5 ± 4.4% in Group A to 3.2 ± 5.7% in Group B (P= 0.001). The mean number of distal anastomoses was significantly increased over time (total: 2.6 ± 0.8 vs 3.1 ± 1.0, P< 0.0001 and with arterial grafts: 1.6 ± 0.8 vs 2.6 ± 0.9, P< 0.0001). In-hospital mortality was low and did not significantly differ between Groups A and B (1.3 vs 2.4%; P= 0.08). Significant increases of new-onset atrial fibrillation (11.7 vs 21.9%, P= 0.017) and deep sternal infection (0.2 vs 1.1%, P= 0.017) were observed in Group B, compared with Group A. In multivariate analysis, extensive use of arterial grafts was not a risk factor of hospital mortality or sternal morbidity.

CONCLUSIONS

Despite the increasing risk profiles of patients undergoing CABG, extensive myocardial revascularization using arterial grafts is associated with good early results.

Predictors of Atrial Fibrillation After Coronary Artery Bypass Grafting: A Bayesian Analysis

BACKGROUND

This study was conducted to identify preoperative predictors of postoperative atrial fibrillation (POAF) after isolated coronary artery bypass grafting (CABG) by using a Bayesian analysis that included information from prior studies.

METHODS

We performed a prospective observational study from October 2008 to December 2013 of 1,481 patients who underwent isolated CABG with cardiopulmonary bypass and had no history of AF. Bayesian analysis was used to study the preoperative risks factors for POAF.

RESULTS

The POAF incidence was 21%. Multivariate analysis identified the following independent predictors of POAF after CABG: high CHA₂DS₂-VASc (Congestive heart failure, Hypertension [blood pressure >140/90 mm Hg or treated hypertension on medication], Age ≥75 years, Diabetes mellitus, prior Stroke or transient ischemic attack or thromboembolism, vascular disease, Age 65 to 74 years, Sex category [female sex]) score (odds ratio [OR], 1.23; 95% credible interval [CI], 1.14 to 1.33 per 1-point increment, probability (Pr) [OR > 1] = 1), severe obesity with a body mass index of 35 kg/m² or higher (OR, 1.28; 95% CI, 1.12 to 1.45; Pr [OR > 1] = 1), preoperative β-blocker use (OR, 1.12; 95% CI, 1.06 to 1.20; Pr [OR > 1] = 1), preoperative antiplatelet therapy (OR, 1.75; 95% CI, 1.14 to 2.79, Pr [OR > 1] = 1), and renal insufficiency with a creatinine clearance of less than 60 mL/min (OR, 1.34; 95% CI, 1.03 to 1.74; Pr [OR > 1] = 1).

CONCLUSIONS

This prospective Bayesian analysis identified five independent preoperative predictors of POAF after isolated CABG with cardiopulmonary bypass: CHA₂DS₂-VASc score, severe obesity, preoperative β-blocker use, preoperative antiplatelet therapy, and renal failure. The main interest in the CHA₂DS₂-VASc score as a predictor of POAF is that it is a simple and widely used bedside tool. Patients with these independent predictors of POAF may constitute a target population to test preventive strategies, such as non-antiarrhythmic and antiarrhythmic drugs.

A Snapshot of Coagulopathy After Cardiopulmonary Bypass

Cardiac surgery involving cardiopulmonary bypass (CPB) is often associated with important blood loss, allogeneic blood product usage, morbidity, and mortality. Coagulopathy during CPB is complex, and the current lack of uniformity for triggers and hemostatic agents has led to a wide variability in bleeding treatment. The aim of this review is to provide a simplified picture of the data available on patients’ coagulation status at the end of CPB in order to provide relevant information for the development of tailored transfusion algorithms. A nonsystematic literature review was carried out to identify changes in coagulation parameters during CPB. Both prothrombin time and activated partial thromboplastin time increased during CPB, by a median of 33.3% and 17.9%, respectively. However, there was marked variability across the published studies, indicating these tests may be unreliable for guiding hemostatic therapy. Some thrombin generation (TG) parameters were affected, as indicated by a median increase in TG lag time of 55.0%, a decrease in TG peak of 17.5%, and only a slight decrease in endogenous thrombin potential of 7%. The most affected parameters were fibrinogen levels and platelet count/function. Both plasma fibrinogen concentration and FIBTEM maximum clot firmness decreased during CPB (median change of 36.4% and 33.3%, respectively) as did platelet count (44.5%) and platelet component (34.2%). This review provides initial information regarding changes in coagulation parameters during CPB but highlights the variability in the reported results. Further studies are warranted to guide physicians on the parameters most appropriate to guide hemostatic therapy.

Randomized, double-blinded, placebo-controlled trial of fibrinogen concentrate supplementation after complex cardiac surgery

BACKGROUND

Postoperative bleeding after heart operations is still a common finding, leading to allogeneic blood products transfusion. Fibrinogen and coagulation factors deficiency are possible determinants of bleeding. The experimental hypothesis of this study is that a first-line fibrinogen supplementation avoids the need for fresh frozen plasma (FFP) and reduces the need for any kind of transfusions.

METHODS AND RESULTS

This was a single-center, prospective, randomized, placebo-controlled, double-blinded study. One-hundred sixteen patients undergoing heart surgery with an expected cardiopulmonary bypass duration >90 minutes were admitted to the study. Patients in the treatment arm received fibrinogen concentrate after protamine administration; patients in the control arm received saline solution. In case of ongoing bleeding, patients in the treatment arm could receive prothrombin complex concentrates (PCCs) and those in the control arm saline solution. The primary endpoint was avoidance of any allogeneic blood product. Patients in the treatment arm had a significantly lower rate of any allogeneic blood products transfusion (odds ratio, 0.40; 95% confidence interval, 0.19 to 0.84, P=0.015). The total amount of packed red cells and FFP units transfused was significantly lower in the treatment arm. Postoperative bleeding was significantly (P=0.042) less in the treatment arm (median, 300 mL; interquartile range, 200 to 400 mL) than in the control arm (median, 355 mL; interquartile range, 250 to 600 mL).

CONCLUSIONS

Fibrinogen concentrate limits postoperative bleeding after complex heart surgery, leading to a significant reduction in allogeneic blood products transfusions. No safety issues were raised.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01471730.

How I use fibrinogen replacement therapy in acquired bleeding

Fibrinogen is a critical protein for hemostasis and clot formation. However, transfusion guidelines have variable recommendations for maintaining fibrinogen levels in bleeding patients. An increasing number of studies support the practice of fibrinogen replacement therapy for acquired coagulopathies, and additional studies are underway. Fibrinogen therapy can be administered with cryoprecipitate or fibrinogen concentrates, and clinical practice varies according to their availability and licensing status. Fibrinogen concentrate therapy has been studied in animal models and clinical trials and supports the critical role of fibrinogen repletion in bleeding patients. Point-of-care testing will have an important role in guiding fibrinogen replacement for hemostatic therapy in clinical settings such as cardiovascular surgery, postpartum hemorrhage, and trauma. Fibrinogen therapy is an important component of a multimodal strategy for the treatment of coagulopathic bleeding.