A review of transfusion risks and optimal management of perioperative bleeding with cardiac surgery

Retrospective study assessing outcomes in cardiac surgery after implementation of Quantra

BACKGROUND

The Quantra QPlus System is a cartridge-based device with a unique ultrasound technology that can measure the viscoelastic properties of whole blood during coagulation. These viscoelastic properties correlate directly with hemostatic function. The primary objective of this study was to assess blood product utilization in cardiac surgery patients before and after the implementation of the Quantra QPlus System.

METHODS

Yavapai Regional Medical Center implemented the Quantra QPlus System to aid in their efforts to reduce the transfusion of allogenic blood products and improve outcomes in patients undergoing cardiac surgery. A total of 64 patients were enrolled prior to the utilization of the Quantra (pre-Quantra cohort), and 64 patients were enrolled after (post-Quantra cohort). The pre-Quantra cohort had been managed via standard laboratory assays along with physician discretion for transfusion decisions. The utilization of blood products and frequency of transfusions were compared and analyzed between the two cohorts. (using the Student's t-test) RESULTS: The implementation of the Quantra resulted in a change in the pattern of blood product utilization leading to a demonstrated decrease in the amount of blood products transfused and the associated costs. The amount of FFP transfused was significantly decreased by 97% (P = 0.0004), whereas cryoprecipitate decreased by 67% (P = 0.3134), platelets decreased by 26% (P = 0.4879), and packed red blood cells decreased by 10% (P = 0.8027) however these trends did not reach statistical significance. The acquisition cost of blood products decreased by 41% for total savings of roughly $40,682.

CONCLUSIONS

Use of the Quantra QPlus System has the potential to improve patient blood management and decrease costs. STUDY REGISTERED AT CLINICALTRIALS.GOV: NCT05501730.

Perioperative transfusion and long-term mortality after cardiac surgery: a meta-analysis

OBJECTIVES

Cardiac surgical procedures are associated with a high incidence of periprocedural blood loss and blood transfusion. Although both may be associated with a range of postoperative complications there is disagreement on the impact of blood transfusion on long-term mortality. This study aims to provide a comprehensive review of the published outcomes of perioperative blood transfusion, examined as a whole and by index procedure.

METHODS

A systematic review of perioperative blood transfusion cardiac surgical patients was conducted. Outcomes related to blood transfusion were analysed in a meta-analysis and aggregate survival data were derived to examine long-term survival.

RESULTS

Thirty-nine studies with 180,074 patients were identified, the majority (61.2%) undergoing coronary artery bypass surgery. Perioperative blood transfusions were noted in 42.2% of patients and was associated with significantly higher early mortality (OR 3.87, p < 0.001). After a median of 6.4 years (range 1-15), mortality remained significantly higher for those who received a perioperative transfusion (OR 2.01, p < 0.001). Pooled hazard ratio for long-term mortality similar for patients who underwent coronary surgery compared to isolated valve surgery. Differences in long-term mortality for all comers remained true when corrected for early mortality and when only including propensity matched studies.

CONCLUSIONS

Perioperative red blood transfusion appears to be associated with a significant reduction in long-term survival for patients after cardiac surgery. Strategies such as preoperative optimisation, intraoperative blood conservation, judicious use of postoperative transfusions, and professional development into minimally invasive techniques should be utilised where appropriate to minimise the need for perioperative transfusions.

Factor eight inhibitor bypassing activity for refractory bleeding in coronary artery bypass grafting: A propensity-matched analysis

Background

Perioperative bleeding and transfusion have been associated with major morbidity and mortality after cardiac surgery. As concerns remain regarding potential graft thrombosis following administration of a prothrombin factor concentrate, the use of factor eight inhibitor bypassing activity (FEIBA) in managing refractory postoperative bleeding has never been evaluated in patients undergoing isolated coronary artery bypass grafting (CABG).

Objectives

We aimed to examine the safety of FEIBA in patients undergoing isolated CABG, with respect to 30-day mortality, perioperative outcomes, and thrombotic complications.

Methods

A retrospective review was undertaken of all consecutive patients who had undergone isolated on-pump CABG between January 2015 and December 2019 at North Shore University Hospital. Patients requiring intraoperative extracorporeal membrane oxygenator support were excluded. Patients were divided into two groups, dependent upon whether they received FEIBA (n = 63) versus no FEIBA (n = 2493). A 1:5 propensity match analysis was employed, and patients were analyzed with respect to thrombotic complications, reintervention for myocardial ischemia, and short-term clinical outcomes.

Results

There was no difference in 30-day mortality between the two cohorts. There was also no significant difference in a composite of thrombotic complications (composed of deep vein thrombosis, pulmonary embolism, and stroke) between the two groups. Similarly, there was no significant difference in the requirement for postoperative reintervention for myocardial ischemia between patients who received FEIBA versus those who did not.

Conclusions

Factor eight inhibitor bypassing activity may be safe when used as rescue therapy for refractory bleeding following isolated CABG.

Perioperative Clinical Trials in AKI

To characterize current evidence and current foci of perioperative clinical trials, we systematically reviewed Medline and identified perioperative trials involving 100 or more adult patients undergoing surgery and reporting renal end points that were published in high-impact journals since 2004. We categorized the 101 trials identified based on the nature of the intervention and summarized major trial findings from the five categories most applicable to perioperative management of patients. Trials that targeted ischemia suggested that increasing perioperative renal oxygen delivery with inotropes or blood transfusion does not reliably mitigate acute kidney injury (AKI), although goal-directed therapy with hemodynamic monitors appeared beneficial in some trials. Trials that have targeted inflammation or oxidative stress, including studies of nonsteroidal anti-inflammatory drugs, steroids, N-acetylcysteine, and sodium bicarbonate, have not shown renal benefits, and high-dose perioperative statin treatment increased AKI in some patient groups in two large trials. Balanced crystalloid intravenous fluids appear safer than saline, and crystalloids appear safer than colloids. Liberal compared with restrictive fluid administration reduced AKI in a recent large trial in open abdominal surgery. Remote ischemic preconditioning, although effective in several smaller trials, failed to reduce AKI in two larger trials. The translation of promising preclinical therapies to patients undergoing surgery remains poor, and most interventions that reduced perioperative AKI compared novel surgical management techniques or existing processes of care rather than novel pharmacologic interventions.

The Use of Factor Eight Inhibitor Bypass Activity (FEIBA) for the Treatment of Perioperative Hemorrhage in Left Ventricular Assist Device Implantation

OBJECTIVE

To test the hypothesis that factor eight inhibitor bypassing activity (FEIBA) can be used to control bleeding following left ventricular assist device (LVAD) implantation without increasing the 14-day composite thrombotic outcome of pump thrombus, ischemic cerebrovascular accidents, pulmonary embolism, and deep venous thrombosis.

DESIGN

Retrospective cohort study.

SETTING

Academic hospital.

PARTICIPANTS

Three hundred nineteen consecutive patients who underwent LVAD implantation (December 1, 2009 to December 30, 2018).

INTERVENTION

FEIBA administered to control perioperative hemorrhage.

MEASUREMENTS AND MAIN RESULTS

The 82 patients (25.7%) in the FEIBA cohort had more risk factors for perioperative hemorrhage, such as lower preoperative platelet count (169 ± 66 v 194 ± 68 × 10³/mL, p = 0.004), prior cardiac surgery (36.6% v 21.9%, p = 0.008), and longer cardiopulmonary bypass (CPB) time (100.3 v 75.2 minutes, p = 0.001) than the 237 controls. After 16.6 units (95% CI: 14.3-18.9) of blood products were given, 992 units (95% CI: 821-1163) of FEIBA were required to control bleeding in the FEIBA cohort. Compared to the controls, there were no differences in the 14-day composite thrombotic outcome (11.0% v 7.6%, p = 0.343) or mortality rate (3.7% v 1.3%, p = 0.179). Multivariate logistical regression identified preoperative international normalized ratio (odds ratio [OR]: 1.30, 95% CI: 1.04-1.62) and CPB time (OR: 1.11, 95% CI: 1.02-1.20) as risk factors for 14-day thrombotic events, but FEIBA usage was not associated with an increased risk.

CONCLUSIONS

In this retrospective cohort study, the use of FEIBA (∼1,000 units, ∼13 units/kg) to control perioperative hemorrhage following LVAD implantation was not associated with increases in mortality or composite thrombotic outcome.

Perioperative hyperfibrinolysis - physiology and pathophysiology

Introduction and objectives

The role of the anesthesiologist in the perioperative management of hemostasis has attracted increasing attention. The fibrinolytic system participates in hemostasis, removing clots after repair of the vascular injury. Over the past two decades, several studies have assessed the efficacy and safety of antifibrinolytic agents in reducing perioperative bleeding and transfusion requirements. Some of the conditions that seem to benefit from antifibrinolytic drugs involve trauma, postpartum hemorrhage, cardiac surgery, spine surgery, knee or hip arthroplasty, urological and gynecological surgery, among others. However, there are currently few publications focusing on the perioperative features of fibrinolytic system, which will be the subject of the present review.

Content and conclusions

Fibrinolytic physiology, its relationship with the clot structure and its perioperative behavior are described. Pathophysiological mechanisms related to anesthesiology clinical practice and their possible perioperative scenarios are addressed according to a suggested classification. This article aims to provide anesthesiologists with a broader understanding of the normal functioning of fibrinolysis, the mechanisms of possible deviations from normality in the perioperative period, the pathophysiological rationale supporting the current indications of antifibrinolytics, and some recent outcomes obtained with their use.

Effect of acute normovolemic hemodilution on coronary artery bypass grafting: A systematic review and meta-analysis of 22 randomized trials

BACKGROUND

Efficacy of minimal acute normovolemic hemodilution (ANH) in avoiding homologous blood transfusion during cardiovascular surgery remains controversial. Postoperative bleeding and transfusion remain a source of morbidity and cost after open heart operations. To better understand the role of acute normovolemic hemodilution (ANH) in coronary artery bypass grafting (CABG), we compared ANH with standard intraoperative care in a systematic review including a standard pairwise meta-analysis of randomized controlled trials (RCTs).

METHODS

We searched the Cochrane Library, PubMed, EMBASE, Web of Science and Chinese National Knowledge Infrastructure (CNKI) up to April 1, 2020. The primary outcome was to assess the incidence of ANH-related number of allogeneic red blood cell units (ARBCu) transfused. Secondary outcomes included the rate of allogeneic blood transfusion and estimated total blood loss.

RESULTS

A total of 22 RCTs including 1688 patients were identified for the present meta-analysis. Of these studies, 19 were about CABG with on-pump and three with off-pump. Our pooled result indicated that patients received ANH experienced fewer ARBCu transfusions, with a standardized mean difference (SMD) of -0.60 (95%CI -0.96 to -0.24; P = 0.001). The rate of allogeneic blood transfusion in ANH group was significant reduced when compared with controls, with a relative risk (RR) of 0.65 (95%CI 0.52 to 0.82; P = 0.0002). In addition, less postoperative estimated total blood loss was present, with a SMD of -0.53 (95%CI -0.88 to -0.17; P = 0.004).

CONCLUSIONS

The present meta-analysis indicated that ANH could reduce the number of ARBCu transfused in the CABG surgery setting. In addition, ANH could also reduce the rate of ARBCu transfusion and estimated total blood loss for CABG patients.

Implementation of Perioperative Point-of-Care Platelet Function Analyses Reduces Transfusion Requirements in Cardiac Surgery: A Retrospective Cohort Study

Background Platelet dysfunction is a common cause of bleeding, perioperative blood transfusion, and surgical re-exploration in cardiac surgical patients. We evaluated the effect of incorporating a platelet function analyzer utilizing impedance aggregometry (Multiplate, Roche, Munich, Germany) into our local transfusion algorithm on the rate of platelet transfusion and postoperative blood loss in patients undergoing coronary artery bypass grafting (CABG) surgery.

Methods Data were collected on patients undergoing CABG surgery from January 2015 to April 2017. Patients who underwent surgery before and after introduction of this algorithm were classified into prealgorithm and postalgorithm groups, respectively. The primary outcome was the rate of platelet transfusion before and after implementation of the Multiplate-based transfusion algorithm. Secondary outcomes included transfusion rate of packed red blood cells, postoperative blood loss at 12 and 24 hours, length of stay in the intensive care unit, and the hospital and mortality.

Results A total of 726 patients were included in this analysis with 360 and 366 patients in the pre- and postalgorithm groups, respectively. Transfusion rates of platelets (p = 0.01) and packed red blood cells (p = 0.0004) were significantly lower following introduction of the algorithm in patients (n = 257) who had insufficient time to withhold antiplatelet agents. Receiver operating characteristic curves defined optimal cutoff points of arachidonic acid and adenosine diphosphate assays on the Multiplate to predict future platelet transfusion were 23AU and 43AU, respectively.

Conclusions The introduction of a Multiplate-based platelet transfusion algorithm showed a statistically significant reduction in the administration of platelets to patients undergoing urgent CABG surgery.

Plasma and Urinary FGF-2 and VEGF-A Levels Identify Children at Risk for Severe Bleeding after Pediatric Cardiopulmonary Bypass: A Pilot Study

Severe bleeding after cardiothoracic surgery with cardiopulmonary bypass (CPB) is associated with increased morbidity and mortality in adults and children. Fibroblast Growth Factor-2 (FGF-2) and Vascular Endothelial Growth Factor-A (VEGF-A) induce hemorrhage in murine models with heparin exposure. We aim to determine if plasma and urine levels of FGF-2 and VEGF-A in the immediate perioperative period can identify children with severe bleeding after CPB. We performed a prospective, observational biomarker study in 64 children undergoing CPB for congenital heart disease repair from June 2015 - January 2017 in a tertiary pediatric referral center. Primary outcome was severe bleeding defined as ≥ 20% estimated blood volume loss within 24-hours. Independent variables included perioperative plasma and urinary FGF-2 and VEGF-A levels. Analyses included comparative (Wilcoxon rank sum, Fisher's exact, and Student's t tests) and discriminative (receiver operator characteristic [ROC] curve) analyses. Forty-eight (75%) children developed severe bleeding. Median plasma and urinary FGF-2 and VEGF-A levels were elevated in children with severe bleeding compared to without bleeding (preoperative: plasma FGF-2 = 16[10-35] vs. 9[2-13] pg/ml; urine FGF-2= 28[15-76] vs. 14.5[1.5-22] pg/mg; postoperative: plasma VEGF-A = 146[34-379] vs. 53 [0-134] pg/ml; urine VEGF-A = 132 [52-257] vs. 45[0.1-144] pg/mg; all p < 0.05). ROC curve analyses of combined plasma and urinary FGF-2 and VEGF-A levels discriminated severe postoperative bleeding (AUC: 0.73-0.77) with mean sensitivity and specificity above 80%. We conclude that the perioperative plasma and urinary levels of FGF-2 and VEGF-A discriminate risk of severe bleeding after pediatric CPB.

Thrombin generation and bleeding in cardiac surgery: a clinical narrative review

This narrative review discusses the role of thrombin generation in coagulation and bleeding in cardiac surgery, the laboratory methods for clinical detection of impaired thrombin generation, and the available hemostatic interventions that can be used to improve thrombin generation. Coagulopathy after cardiopulmonary bypass (CPB) is associated with excessive blood loss and adverse patient outcomes. Thrombin plays a crucial role in primary hemostasis, and impaired thrombin generation can be an important cause of post-CPB coagulopathy. Existing coagulation assays have significant limitations in assessing thrombin generation, but whole-blood assays designed to measure thrombin generation at the bed-side are under development. Until then, clinicians may need to institute therapy empirically for non-surgical bleeding in the setting of normal coagulation measures. Available therapies for impaired thrombin generation include administration of plasma, prothrombin complex concentrate, and bypassing agents (recombinant activated factor VII and factor eight inhibitor bypassing activity). In vitro experiments have explored the relative potency of these therapies, but clinical studies are lacking. The potential incorporation of thrombin generation assays into clinical practice and treatment algorithms for impaired thrombin generation must await further clinical development.

Evaluation of platelet count and platelet function analyzer - 100 testing for prediction of platelet transfusion following coronary bypass surgery

Platelet transfusions are commonly administered to treat bleeding in cardiac surgery. The aim of this study was to compare platelet (PLT) count and values of collagen adenosine diphosphate closure time (cADP-CT) measured by Platelet Function Analyzer (PFA) for prediction of PLT transfusion therapy following coronary bypass surgery. For this prospective observational study, 66 patients scheduled for coronary artery bypass grafting (CABG) who received early PLT transfusions (within 60 min after the operation) were enrolled. To assess changes in platelets, count and function, two time points were selected: 15 min before and 30 - 60 min after the end of PLT transfusion. The patients were divided into transfused and non-transfused with further PLT in the 48 h postoperatively. We used the receiver operating characteristics (ROC) curve to investigate whether the PLT count and cADP-CT values were predictors of PLT transfusion. The positive predictive values (PPV) of PLT count and cADP-CT after PLT transfusion for further PLT transfusion were 33% and 86% respectively, with a PLT count threshold of ≤200 × 10⁹/L and cADP-CT threshold of ≥118 s. The comparison among the ROC curves showed a statistical difference (p = .0002). In multiple regression analysis, cADP-CT was the strongest predictor for the number of PLT transfusion doses in the 48 h postoperatively. In CABG patients, the results of cADP-CT after PLT transfusion have a better predictive capacity for further PLT transfusions than the PLT count.

Mortality and Factors Associated With Hemorrhage During Pediatric Extracorporeal Membrane Oxygenation

OBJECTIVES

To quantify and identify factors associated with bleeding events during pediatric extracorporeal membrane oxygenation.

DESIGN

Retrospective cohort study with primary outcome of bleeding days on extracorporeal membrane oxygenation.

SETTING

Single tertiary care children's hospital.

SUBJECTS

One-hundred twenty-two children supported with extracorporeal membrane oxygenation for greater than 12 hours during January 2015 through December 2016.

INTERVENTIONS

Bleeding days were identified if mediastinal or cannula site exploration, activated factor VII administration, gastrointestinal, pulmonary, or intracranial hemorrhages occurred. Logistic regression was used to assess factors associated with bleeding days.

MEASUREMENTS AND MAIN RESULTS

Study population was identified from institutional extracorporeal membrane oxygenation database. Clinical, laboratory, and survival data were obtained from medical records. Only data from patients' first extracorporeal membrane oxygenation run were used. One-hundred twenty-two patients with median age of 17 weeks (interquartile range, 1-148 wk) were analyzed. Congenital heart disease (n = 56, 46%) was the most common diagnosis. Bleeding days comprised 179 (16%) of the 1,121 observed extracorporeal membrane oxygenation-patient-days. By extracorporeal membrane oxygenation day 4, 50% of users had experienced a bleeding day. Central rather than peripheral cannulation (odds ratio, 2.58; 95% CI, 1.47-4.52; p < 0.001), older age (odds ratio, 1.31 per increased week; 95% CI, 1.14-1.52; p < 0.001), higher lactate (odds ratio, 1.08 per 1 mmol/L increase; 95% CI, 1.05-1.12; p < 0.001), and lower platelets (odds ratio, 0.87 per 25,000 cell/μL increase; 95% CI, 0.77-0.99; p = 0.005) were associated with bleeding days. Patients who experienced more frequent bleeding (> 75th percentile) had fewer ventilator-free and hospital-free days in the 60 days after cannulation (0 vs 31; p = 0.002 and 0 vs 0; p = 0.008) and higher in-hospital mortality (68 vs 34%; p < 0.001).

CONCLUSIONS

Central cannulation, older age, low platelets, and high lactate are associated with bleeding days during pediatric extracorporeal membrane oxygenation. Patients who bleed more frequently during extracorporeal membrane oxygenation have higher in-hospital mortality, longer technological dependence, and reduced hospital-free days.

Factor XIII activity in patients requiring surgical re-exploration for bleeding after elective cardiac surgery - A prospective case control study

PURPOSE

Surgical re-exploration due to postoperative bleeding is associated with increased morbidity and mortality. The aim of our study was to assess a potential association between the level of postoperative FXIII activity and need for re-exploration due to bleeding in patients undergoing cardiothoracic surgery.

MATERIALS AND METHODS

In our prospective single center observational cohort study, we enrolled patients who underwent elective cardiothoracic surgery. Patients who required re-exploration (RE group) were matched to patients from the study population (non-RE group).

RESULTS

The study included 64 patients, out of a cohort of 678 patients, of whom 32 required surgical re-exploration due to bleeding within the first 24 h. Between patients of the RE and non-RE group, a significantly reduced FXIII activity was observed postoperatively (59.0 vs 71.1; p = .014). Multivariable analysis revealed reduced FXIII activity (p = .048) as a parameter independently associated with surgical re-exploration. Further, reduced FXIII activity (p = .037) and surgical re-exploration (p = .01) were significantly associated with increased 30 day mortality. In multivariable analysis re-exploration was independently associated with increased risk of 30 day mortality (p = .004, HR 9.68).

CONCLUSIONS

Reduced postoperative FXIII activity may be associated with the need for surgical re-exploration. Postoperative assessment of FXIII activity should therefore be considered in patients undergoing elective cardiothoracic surgery.

Noninvasive Continuous Hemoglobin Monitoring: Role in Cardiovascular Surgery

Blood transfusions in the operating room are associated with increased morbidity and mortality as well as increased cost. The technology exists for continuous noninvasive hemoglobin monitoring (SpHb), which could allow for the rapid diagnosis and treatment of acute blood loss anemia secondary to surgical bleeding. However, the accuracy of this technology has been called into question. SpHb in the operating room could reduce cost by decreasing lab draws, unnecessary transfusions, and the morbidity associated with blood transfusions. This review examines the accuracy of noninvasive hemoglobin monitoring as well as the role it may play in the operating room.

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.

Preventing and managing catastrophic bleeding during extracorporeal circulation

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

Perioperative point of care platelet function testing and postoperative blood loss in high-risk cardiac surgery patients

Postoperative coagulopathic bleeding is common in cardiac surgery and associated with increased morbidity and mortality. Platelet function is affected by multiple factors, including patient and procedural characteristics. Point-of-care (POC) multiple electrode aggregometry (MEA) can rapidly detect and quantify platelet dysfunction and could contribute to optimal patient blood management. In patients undergoing CABG and heart valve surgery platelet function was assessed using POC MEA at four different perioperative timepoints in response to stimulation with four specific receptor agonists (ADP, AA, COL, TRAP). Postoperative bleeding was recorded during 24 h after surgery. Regression analyses were performed to establish associations between perioperative platelet function and postoperative blood loss. Ninety-nine patients were included in the study. Fifty-nine patients (60%) were on antiplatelet therapy (APT) at time of surgery. ADP- and AA-induced platelet aggregation declined during CPB and after decannulation from CPB, with a maximum decrease of 55% for ADP (35 vs. 77 AU at baseline; P < 0.001) and 78% for ASPI (14 vs. 64 AU at baseline; P < 0.001). A linear relationship was present between ADP-induced platelet aggregometry at baseline and postoperative blood loss (r = -0.249; P = 0.015). In aspirin users, the maximum decline in platelet function between baseline and CPB decannulation was related to postoperative blood loss (r = 0.308; P = 0.037). In multivariate analysis, a reduced ADP platelet function prior to surgery remained associated with postoperative blood loss (r = -0.239; P = 0.012). Reduced ADP-induced platelet aggregation at baseline is associated with increased postoperative blood loss in high-risk cardiac surgery patients.

Factors influencing transfusion requirement in patients undergoing first-time, elective coronary artery bypass graft surgery

CONTEXT

Coronary artery bypass graft (CABG) operation is associated with high frequency of allogeneic blood transfusion due to the acquired hemostatic challenges in patients undergoing CABG. However, allogeneic blood transfusion carries risks of infection, adverse reaction, and mortality as well as prolonged hospital stay and increased hospital cost. It is important to identify patients who require blood transfusion to mitigate their risk factors and reduce the chance of exposure to allogeneic blood.

AIMS

This study was conducted to evaluate factors that influence the decision to transfuse red cell in first-time elective CABG patients.

SETTINGS AND DESIGN

This was a cross-sectional study based on a retrospective record review. The study was done in the National Heart Institute.

MATERIALS AND METHODS

All patients who underwent first-time elective CABG were included in this study. Variables analyzed include age, gender, body weight, preoperative hemoglobin (Hb) level, patients' comorbidities, and other clinical parameters.

STATISTICAL ANALYSIS USED

Data were analyzed using SPSS software version 20.

RESULTS

A total of 463 patients underwent first-time elective CABG during the period of the study. Three hundred and eighty-six (83.4%) patients received red cell transfusion. From multiple logistic regression analysis, only age (odds ratio [OR] = 1.040, 95% confidence interval [CI]: 1.003, 1.077, P = 0.032), body weight (OR = 0.951, 95% CI: 0.928, 0.974, P < 0.001), Hb level (OR = 0.500, 95% CI: 0.387, 0.644, P < 0.001), and cardiopulmonary bypass time (OR = 1.013, 95% CI: 1.004, 1.023, P < 0.001) were the significant independent predictors of red cell transfusion.

CONCLUSIONS

By stratifying patients according to their risk factor for red cell transfusion, the high-risk patients could be recognized and should be enrolled into effective patient blood management program to minimize their risk of exposure to allogeneic blood transfusion.

Recombinant Factor VIIa to Manage Major Bleeding from Newer Parenteral Anticoagulants

Objective

To evaluate the use of recombinant factor VIIa (rFVIIa) to reverse major bleeding from newer parenteral anticoagulant therapy.

Data sources

MEDLINE/PubMed was searched from January 2000 through December 2009 using the terms recombinant factor VIIa, rFVIIa, NovoSeven, enoxaparin, argatroban, fondaparinux, lepirudin, bivalirudin, idraparinux, nadroparin, hirudin, and desirudin. References of identified articles were reviewed.

Data synthesis

Data evaluating the role of rFVIIa to reverse major bleeding from newer parenteral anticoagulant therapy is limited to case reports and small laboratory investigations. Laboratory investigations suggest that rFVIIa may be effective in reversing the hemostatic effects of newer parenteral anticoagulants. In most case reports analyzed, standard interventions for bleeding (eg, fresh frozen plasma, packed red blood cells) were attempted prior to using rFVIIa. Sixteen published cases describe the use of rFVIIa to reverse major bleeding from low-molecular-weight heparins, synthetic pentasaccharides, and direct thrombin inhibitors. Initial doses ranged from 20 to 120 μg/kg. rFVIIa was considered effective or partially effective based upon clinical response in 13 cases. Use was not effective in 3 cases because of a thrombotic event, no change in hemostasis, and death from bleeding complications. As thrombosis is the major safety concern, an individualized risk-benefit assessment is required prior to the use of rFVIIa therapy to restore hemostasis.

Conclusions

rFVIIa may be considered to manage major refractory bleeding from newer parenteral anticoagulant agents when the benefit is thought to outweigh the thrombotic risk.

Oxygenation via a Biventricular Assist Device for Emergency Airway Management

A 56-year-old man receiving mechanical circulatory support via a biventricular assist device suffered an airway emergency secondary to bleeding into the airway. An improvised solution to gain control of the airway in the short term was devised, and an oxygenator was inserted into the circuit, providing an alternative means of gas exchange while definitive control of the airway was achieved. This case changed practice in our institution, where we now make contingency plans for emergency oxygenator insertion into the circuits of all patients with a biventricular assist device who show any sign of airway hemorrhage.

Point-of-Care Hemostatic Testing in Cardiac Surgery: A Stepped-Wedge Clustered Randomized Controlled Trial

BACKGROUND

Cardiac surgery is frequently complicated by coagulopathic bleeding that is difficult to optimally manage using standard hemostatic testing. We hypothesized that point-of-care hemostatic testing within the context of an integrated transfusion algorithm would improve the management of coagulopathy in cardiac surgery and thereby reduce blood transfusions.

METHODS

We conducted a pragmatic multicenter stepped-wedge cluster randomized controlled trial of a point-of-care-based transfusion algorithm in consecutive patients undergoing cardiac surgery with cardiopulmonary bypass at 12 hospitals from October 6, 2014, to May 1, 2015. Following a 1-month data collection at all participating hospitals, a transfusion algorithm incorporating point-of-care hemostatic testing was sequentially implemented at 2 hospitals at a time in 1-month intervals, with the implementation order randomly assigned. No other aspects of care were modified. The primary outcome was red blood cell transfusion from surgery to postoperative day 7. Other outcomes included transfusion of other blood products, major bleeding, and major complications. The analysis adjusted for secular time trends, within-hospital clustering, and patient-level risk factors. All outcomes and analyses were prespecified before study initiation.

RESULTS

Among the 7402 patients studied, 3555 underwent surgery during the control phase and 3847 during the intervention phase. Overall, 3329 (45.0%) received red blood cells, 1863 (25.2%) received platelets, 1645 (22.2%) received plasma, and 394 (5.3%) received cryoprecipitate. Major bleeding occurred in 1773 (24.1%) patients, and major complications occurred in 740 (10.2%) patients. The trial intervention reduced rates of red blood cell transfusion (adjusted relative risk, 0.91; 95% confidence interval, 0.85-0.98; P=0.02; number needed to treat, 24.7), platelet transfusion (relative risk, 0.77; 95% confidence interval, 0.68-0.87; P<0.001; number needed to treat, 16.7), and major bleeding (relative risk, 0.83; 95% confidence interval, 0.72-0.94; P=0.004; number needed to treat, 22.6), but had no effect on other blood product transfusions or major complications.

CONCLUSIONS

Implementation of point-of-care hemostatic testing within the context of an integrated transfusion algorithm reduces red blood cell transfusions, platelet transfusions, and major bleeding following cardiac surgery. Our findings support the broader adoption of point-of-care hemostatic testing into clinical practice.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02200419.

Economic aspects of intraoperative coagulation management targeting higher fibrinogen concentrations during major craniosynostosis surgery

BACKGROUND

Results of a previously published study demonstrated a significant decrease in transfusion requirements and calculated blood loss for pediatric major craniosynostosis surgery, if a ROTEM(®) FIBTEM trigger of <13 mm (early substitution group) was applied as compared to a trigger of <8 mm (conventional group). The aim of this study was a posthoc analysis of the costs for this coagulation management.

METHODS

The total volume as well as the number of units or bags for all transfused blood products and coagulation factors were recorded for each case. The number of laboratory and point-of-care coagulation tests was also analyzed. Total blood product costs were calculated according to the local prices per unit.

RESULTS

The total cost for all transfused/administered blood products/coagulation factors per patient was a median of 1023EUR (IQR 850EUR-1058EUR) in the early substitution group as compared to a median of 910EUR (IQR 719EUR-1351EUR) in the conventional group (P = 0.81). No difference in the number of coagulation tests performed was observed.

CONCLUSION

In this study, the use of a higher fibrinogen trigger was not linked to a significant increase in total costs for transfused blood products and coagulation factors, and may offer an economically equivalent approach to coagulation management.

Single vs double antiplatelet therapy in acute coronary syndrome: Predictors of bleeding after coronary artery bypass grafting

AIM: To investigate the contribution of anti-platelet therapy and derangements of pre-operative classical coagulation and thromboelastometry parameters to major bleeding post-coronary artery bypass grafting (CABG).

METHODS: Two groups of CABG patients were studied: Group A, treated with aspirin alone (n = 50), and Group B treated with aspirin and clopidogrel (n = 50). Both had similar preoperative, clinical, biologic characteristics and operative management. Classic coagulation parameters and rotational thromboelastometry (ROTEM) profiles were determined preoperatively for both groups and the same heparin treatment was administered. ROTEM profiles (INTEM and EXTEM assays) were analyzed, both for traditional parameters, and thrombin generation potential, expressed by area-under-curve (AUC).

RESULTS: There was no significant difference between rates of major bleeding between patients treated with aspirin alone, compared with those treated with aspirin and clopidogrel (12% vs 16%, P = 0.77). In the 14 cases of major bleeding, pre-operative classic coagulation and traditional ROTEM parameters were comparable. Conversely we observed that the AUC in the EXTEM test was significantly lower in bleeders (5030 ± 1115 Ohm*min) than non-bleeders (6568 ± 548 Ohm*min) (P < 0.0001).

CONCLUSION: We observed that patients with a low AUC value were at a significantly higher risk of bleeding compared to patients with higher AUC, regardless of antiplatelet treatment. This suggests that thrombin generation potential, irrespective of the degree of platelet inhibition, correlates with surgical bleeding.

An Interdisciplinary Education Initiative to Promote Blood Conservation in Cardiac Surgery

Transfusion practices vary extensively for patients undergoing cardiac surgical procedures, leading to high utilization of blood products despite evidence that transfusions negatively impact outcomes. An important factor affecting transfusion practice is recognition of the importance of teams in cardiac surgery care delivery. This article reports an evidenced-based practice (EBP) initiative constructed using the Society of Thoracic Surgery (STS) 2011 Blood Conservation Clinical Practice Guidelines (CPGs) to standardize transfusion practice across the cardiac surgery team at a large academic medical center. Project outcomes included: a) Improvement in clinician knowledge related to the STS Blood Conservation CPGs; and b) Decreased blood product utilization for patients undergoing cardiac surgical procedures. Participants' scores reflected an improvement in the overall knowledge of the STS CPGs noting a 31.1% (p = 0.012) increase in the number of participants whose practice reflected the Blood Conservation CPGs post intervention. Additionally, there was a reduction in overall blood product utilization for all patients undergoing cardiac surgery procedures post intervention (p = 0.005). Interdisciplinary education based on the STS Blood Conservation CPGs is an effective way to reduce transfusion practice variability and decrease utilization of blood products during cardiac surgery.

Near-Infrared Spectroscopy Hemoglobin Index Measurement During Fluid Challenge: A Prospective Study in Cardiac Surgery Patients

OBJECTIVE

Little is known about changes in near-infrared spectroscopy-derived tissue hemoglobin index (HbI). The authors tested the hypothesis that absolute values and changes in brain hemoglobin index (HbIb) and skeletal muscle hemoglobin index (HbIm) could differ from the reference arterial hemoglobin (Hb) during fluid challenge.

DESIGN

A prospective, monocenter observational study.

SETTING

A 16-bed cardiac surgical intensive care unit in a teaching university hospital.

PARTICIPANTS

Fifty consecutive adult patients.

INTERVENTIONS

Investigation before and after a fluid challenge.

MEASUREMENTS AND MAIN RESULTS

Simultaneous comparative Hb, HbIb and HbIm data points were collected from a blood-gas analyzer and the EQUANOX device (Nonin Medical Inc., Plymouth, MN). Correlations were determined by linear regression. No significant relationship was found between absolute values of Hb and HbIb before (R(2)= 0.04, p = 0.627) and after (R(2) = 0.00006, p = 0.956) fluid challenge. No significant relationship was found between absolute values of Hb and HbIm before (R(2)= 0.030, p = 0.226) and after (R(2) = 0.05, p = 0.117) the fluid challenge. No significant relationship was found between changes in Hb and HbIb (R(2)= 0.26, p = 0.263) and between changes in Hb and HbIm (R(2) = 0.001, p = 0.801) after the fluid challenge. Bland-Altman analysis showed a poor concordance between changes in Hb and HbIb, and changes in Hb and HbIm, with large limits of agreement.

CONCLUSIONS

HbIb and HbIm cannot be used to provide continuous noninvasive estimation of Hb, and trends in HbIb and HbIm cannot be considered as noninvasive surrogates for the trend in Hb after cardiac surgery.

Extracorporeal membrane oxygenation-hemostatic complications

The use of extracorporeal membrane oxygenation (ECMO) support for cardiac and respiratory failure has increased in recent years. Improvements in ECMO oxygenator and pump technologies have aided this increase in utilization. Additionally, reports of successful outcomes in supporting patients with respiratory failure during the 2009 H1N1 pandemic and reports of ECMO during cardiopulmonary resuscitation have led to increased uptake of ECMO. Patients requiring ECMO are a heterogenous group of critically ill patients with cardiac and respiratory failure. Bleeding and thrombotic complications remain a leading cause of morbidity and mortality in patients on ECMO. In this review, we describe the mechanisms and management of hemostatic, thrombotic and hemolytic complications during ECMO support.

Can plasma fibrinogen levels predict bleeding after coronary artery bypass grafting?

BACKGROUND

Fibrinogen is the main biomarker for bleeding. To prevent excessive postoperative bleeding, it would be useful to identify high-risk patients before coronary artery bypass grafting (CABG).

OBJECTIVES

In order to predicating bleeding after CABG, we sought to determine whether preoperative fibrinogen concentration was associated with the amount of bleeding following CABG.

PATIENTS AND METHODS

A total of 144 patients (mean age = 61.50 ± 9.42 years; 65.7% men), undergoing elective and isolated CABG, were included in this case-series study. The same anesthesia technique and medicines were selected for all the patients. In the ICU, the patients were assessed in terms of bleeding at 12 and 24 hours post-operation, amount of contingent blood products received, and relevant tests. Statistical tests were subsequently conducted to analyze the correlation between preoperative fibrinogen concentration and the amount of post-CABG bleeding.

RESULTS

The mean ± standard deviation of bleeding at 12 and 24 hours post-operation was 285.37 ± 280.27 and 499.31 ± 355.57 mL, respectively. The results showed that postoperative bleeding was associated with different factors whereas pre-anesthesia fibrinogen was not correlated with bleeding at 12 (P = 0.856) and 24 hours (P = 0.936) post-operation. There were correlations between the extra-corporal circulation time and bleeding at 12 hours post-operation (ρ = 0.231, P = 0.007) and bleeding at 24 hours post-operation (ρ = 0.218, P = 0.013).

CONCLUSIONS

Preoperative assessment of plasma fibrinogen levels failed to predict post-CABG bleeding.

A 2014 Update on Coagulation Management for Cardiopulmonary Bypass

Coagulopathy after cardiac surgery with cardiopulmonary bypass is a serious complication that may result in massive bleeding requiring transfusion of significant amounts of blood products, plasma, and platelets. In addition to increased patient morbidity and mortality it is associated with longer hospital stay and increased resource utilization. The current review discusses aspects in cardiopulmonary bypass–induced coagulopathy with emphasis on point-of-care testing and individualized “goal-directed” therapy in patients who develop excessive bleeding after cardiac surgery.

Safety and efficacy of prothrombin complex concentrates for the treatment of coagulopathy after cardiac surgery

OBJECTIVE

Coagulopathy is an important cause of bleeding after complex cardiac surgery. The conventional treatment for coagulopathy is transfusion, which is associated with adverse outcomes. We report our initial experience with the prothrombin complex concentrate FEIBA (factor VIII inhibitor bypassing activity) for the rescue treatment of coagulopathy and life-threatening bleeding after cardiac surgery.

METHODS

Twenty-five patients who underwent cardiac surgery with coagulopathy and life-threatening bleeding refractory to conventional treatment received FEIBA as rescue therapy at our institution. This cohort represents approximately 2% of patients undergoing cardiac surgery in our university-based practice during the study.

RESULTS

The patients were at high risk for postoperative coagulopathy with nearly all patients having at least 2 risk factors for this. Aortic root replacement (Bentall or valve-sparing procedure) and heart transplant with or without left ventricular assist device explant were the most common procedures. The mean FEIBA dose was 2154 units. The need for fresh frozen plasma and platelet transfusion decreased significantly after FEIBA administration (P = .0001 and P < .0001). The mean internationalized normalized ratio decreased from 1.58 to 1.13 (P < .0001). Clinical outcomes were excellent. No patient returned to the operating room for reexploration. There was no hospital mortality and all patients were discharged home. One patient who had a central line and transvenous pacemaker developed an upper extremity deep vein thrombosis.

CONCLUSIONS

Our initial experience with FEIBA administration for the rescue treatment of postoperative coagulopathy and life-threatening bleeding has been favorable. Further studies are indicated to confirm its efficacy and safety and determine specific clinical indications for its use in patients undergoing cardiac surgery.

Economic evaluation of cell salvage in pediatric surgery

BACKGROUND

Red blood cells are a scarce resource with demand outstripping supply. Use of intraoperative red cell salvage (CS) - the process of collecting shed blood during surgery and reinfusing it to patients - is often used as an effective blood conservation strategy. However, little is known about the economic impact of CS during pediatric surgery.

METHODS

A decision tree model was used to estimate the transfusion-related costs per patient (2010 USD) from a healthcare system perspective of four transfusion strategies among children undergoing elective orthopedic or cardiac surgery: (i) CS followed by allogeneic transfusion, (ii) CS followed by autologous transfusion, (iii) allogeneic transfusion alone, and (iv) autologous transfusion alone.

RESULTS

Cell salvage and allogeneic transfusion was the least expensive strategy (USD 883.3) followed by CS and autologous blood transfusion (USD 1,269.7), allogeneic transfusion alone (USD 1,443.0), and autologous transfusion alone (USD 1,824.7). Savings associated with CS use persisted in separate analyses of orthopedic and cardiac surgery, as well as in one-way and probabilistic sensitivity analyses.

CONCLUSIONS

Use of CS, particularly along with allogeneic blood transfusion, appears cost-saving and cost-effective in pediatric surgery.

Restoration of the coagulation cascade on CPB: a case report

Coagulopathy can sometimes be observed when CPB times are prolonged. Correction of coagulopathy post CPB can present the surgical team with a number of challenges, including right ventricular volume overload, hemodilution, anemia and excessive cell salvage with further loss of coagulation factors. Restoration of the coagulation cascade on CPB may help to avoid these issues. This case report is of a 64-year-old male with a delayed diagnosis of aortic dissection. The patient presented to the cardiac surgery operating room with hepatic and renal shock/failure, with the resulting coagulopathy. The described technique is representative of a technique that we sometimes employ to restore the clotting mechanism before separating from bypass.

Cardiac surgery-associated acute kidney injury

Cardiac surgery-associated acute kidney injury (AKI) is a major health problem that is extremely common and has a significant effect on cardiac surgical outcomes. AKI occurs in nearly 30 % of patients undergoing cardiac surgery, with about 1-2 % of these ultimately requiring dialysis. The development of AKI predicts a significant increase in morbidity and mortality independent of other risk factors. The pathogenetic mechanisms associated with cardiac surgery-associated AKI include several biochemical pathways, of which the most important are hemodynamic, inflammatory and nephrotoxic factors. Risk factors for AKI have been identified in several models, and these facilitate physicians to prognosticate and develop a strategy for tackling patients predisposed to developing renal dysfunction. Effective therapy of the condition is still suboptimal, and hence the accent has always been on risk factor modification. Thus, strategies for reducing preoperative anemia, perioperative blood transfusions and surgical re-explorations may be effective in attenuating the incidence and severity of this complication.

[Managing of excessive bleeding after cardiac surgery under cardiopulmonary bypass]

The occurrence of abnormal bleeding in postoperative cardiac surgery performed under cardiopulmonary bypass is relatively common. If the option of reoperation is not retained, the initiation of medical treatment is inevitable. Next to the transfusion of blood products, other therapies were often used empirically and as "off-label". The place of each in a future regimen should be based on well-conducted clinical studies to determine the optimal risk/benefit ratio.