Development and Publication of Clinical Practice Parameters, Reviews, and Meta-analyses: A Report From the Society of Cardiovascular Anesthesiologists Presidential Task Force

The Society of Cardiovascular Anesthesiologists (SCA) is committed to improving the quality, safety, and value that cardiothoracic anesthesiologists bring to patient care. To fulfill this mission, the SCA supports the creation of peer-reviewed manuscripts that establish standards, produce guidelines, critically analyze the literature, interpret preexisting guidelines, and allow experts to engage in consensus opinion. The aim of this report, commissioned by the SCA President, is to summarize the distinctions among these publications and describe a novel SCA-supported framework that provides guidance to SCA members for the creation of these publications. The ultimate goal is that through a standardized and transparent process, the SCA will facilitate up-to-date education and implementation of best practices by cardiovascular and thoracic anesthesiologists to improve patient safety, quality of care, and outcomes.

Finding a common definition of heparin resistance in adult cardiac surgery: communication from the ISTH SSC subcommittee on perioperative and critical care thrombosis and hemostasis

Ensuring adequate anticoagulation for patients requiring cardiac surgery and cardiopulmonary bypass (CPB) is important due to the adverse consequences of inadequate anticoagulation with respect to bleeding and thrombosis. When target anticoagulation is not achieved with typical doses, the term heparin resistance is routinely used despite the lack of uniform diagnostic criteria. Prior reports and guidance documents that define heparin resistance in patients requiring CPB and guidance documents remain variable based on the lack of standardized criteria. As a result, we conducted a review of clinical trials and reports to evaluate the various heparin resistance definitions employed in this clinical setting and to identify potential standards for future clinical trials and clinical management. In addition, we also aimed to characterize the differences in the reported incidence of heparin resistance in the adult cardiac surgical literature based on the variability of both target-activated clotting (ACT) values and unfractionated heparin doses. Our findings suggest that the most extensively reported ACT target for CPB is 480 seconds or higher. Although most publications define heparin resistance as a failure to achieve this target after a weight-based dose of either 400 U/kg or 500 U/kg of heparin, a standardized definition would be useful to guide future clinical trials and help improve clinical management. We propose the inability to obtain an ACT target for CPB of 480 seconds or more after 500 U/kg as a standardized definition for heparin resistance in this setting.

Evaluation of the efficacy and safety of amustaline/glutathione pathogen-reduced RBCs in complex cardiac surgery: the Red Cell Pathogen Inactivation (ReCePI) study-protocol for a phase 3, randomized, controlled trial

BACKGROUND

Red blood cell (RBC) transfusion is a critical supportive therapy in cardiovascular surgery (CVS). Donor selection and testing have reduced the risk of transfusion-transmitted infections; however, risks remain from bacteria, emerging viruses, pathogens for which testing is not performed and from residual donor leukocytes. Amustaline (S-303)/glutathione (GSH) treatment pathogen reduction technology is designed to inactivate a broad spectrum of infectious agents and leukocytes in RBC concentrates. The ReCePI study is a Phase 3 clinical trial designed to evaluate the efficacy and safety of pathogen-reduced RBCs transfused for acute anemia in CVS compared to conventional RBCs, and to assess the clinical significance of treatment-emergent RBC antibodies.

METHODS

ReCePI is a prospective, multicenter, randomized, double-blinded, active-controlled, parallel-design, non-inferiority study. Eligible subjects will be randomized up to 7 days before surgery to receive either leukoreduced Test (pathogen reduced) or Control (conventional) RBCs from surgery up to day 7 post-surgery. The primary efficacy endpoint is the proportion of patients transfused with at least one study transfusion with an acute kidney injury (AKI) diagnosis defined as any increased serum creatinine (sCr) level ≥ 0.3 mg/dL (or 26.5 µmol/L) from pre-surgery baseline within 48 ± 4 h of the end of surgery. The primary safety endpoints are the proportion of patients with any treatment-emergent adverse events (TEAEs) related to study RBC transfusion through 28 days, and the proportion of patients with treatment-emergent antibodies with confirmed specificity to pathogen-reduced RBCs through 75 days after the last study transfusion. With ≥ 292 evaluable, transfused patients (> 146 per arm), the study has 80% power to demonstrate non-inferiority, defined as a Test group AKI incidence increase of no more than 50% of the Control group rate, assuming a Control incidence of 30%.

DISCUSSION

RBCs are transfused to prevent tissue hypoxia caused by surgery-induced bleeding and anemia. AKI is a sensitive indicator of renal hypoxia and a novel endpoint for assessing RBC efficacy. The ReCePI study is intended to demonstrate the non-inferiority of pathogen-reduced RBCs to conventional RBCs in the support of renal tissue oxygenation due to acute anemia and to characterize the incidence of treatment-related antibodies to RBCs.

Defining heparin resistance: communication from the ISTH SSC Subcommittee of Perioperative and Critical Care Thrombosis and Hemostasis

The term heparin resistance (HR) is used by clinicians without specific criteria. We performed a literature search and surveyed our SSC membership to better define the term when applied to medical and intensive care unit patients. The most common heparin dosing strategy reported in the literature (53%) and by survey respondents (80.4%) was the use of weight-based dosing. Heparin monitoring results were similar based on the proportion of publications and respondents that reported the use of anti-Xa and activated partial thromboplastin time. The most common literature definition of HR was >35 000 U/d, but no consensus was reported among survey respondents regarding weight-based and the total dose of heparin when determining resistance. Respondent consensus on treating HR included antithrombin supplementation, direct thrombin inhibitors, or administering more heparin as the strategies available for treating HR. A range of definitions for HR exist. Given the common use of heparin weight-based dosing, future publications employing the term HR should include weight-based definitions, monitoring assay, and target level used. Further work is needed to develop a consensus for defining HR.

Mean distance from skin to epiglottis in parturients as measured by airway ultrasound

Introduction

There is an increasing interest in using airway ultrasound to predict difficult intubation. Studies to date have excluded pregnant women in reporting airway measurements. We performed this study to compare the mean distance from skin to epiglottis in parturients to that reported in previously published studies. We also assessed the correlation of mean distance from skin to epiglottis with other elements of the airway examination.

Methods

A total of 100 parturients were recruited from a tertiary hospital's labor and delivery floor. Standard physical examination parameters were recorded in addition to the mean distance from skin to epiglottis for all subjects. The ratio of height-to-thyromental distance was used to classify airways as potentially favorable or unfavorable.

Results

The average mean distance from skin to epiglottis in parturients was 19.9 ± 3.3 mm and followed a normal distribution. The mean distance from skin to epiglottis was moderately correlated with height and body mass index. There was no difference in mean distance from skin to epiglottis between subjects with favorable versus unfavorable airways as classified by ratio of height-to-thyromental distance.

Conclusion

The typical mean distance from skin to epiglottis in parturients falls between previously published values in mixed populations. Previously published cut-off values using airway ultrasound to predict difficult intubation are not likely to apply to parturients.

A Sticky Situation: Variable Agreement Between Platelet Function Tests Used to Assess Anti-platelet Therapy Response

Background

Platelet function testing to monitor antiplatelet therapy is important for reducing thromboembolic complications, yet variability across testing methods remains challenging. Here we evaluated the agreement of four different testing platforms used to monitor antiplatelet effects of aspirin (ASA) or P2Y₁₂ inhibitors (P2Y12-I).

Methods

Blood and urine specimens from 20 patients receiving dual antiplatelet therapy were analyzed by light transmission aggregometry (LTA), whole blood aggregometry (WBA), VerifyNow PRUTest and AspirinWorks. Result interpretation based on pre-defined cutoff values was used to calculate raw agreement indices, and Pearson's correlation coefficient determined using individual units of measure.

Results

Agreement between LTA and WBA for P2Y12-I-response was 60% (r = 0.65, high-dose ADP; r = 0.75, low-dose ADP). VerifyNow agreed with LTA in 75% (r = 0.86, high-dose ADP; r = 0.75, low-dose ADP) and WBA in 55% (r = 0.57) of cases. Agreement between LTA and WBA for ASA-response was 45% (r = 0.09, high-dose collagen WBA; r = 0.19, low-dose collagen WBA). AspirinWorks agreed with LTA in 60% (r = 0.32) and WBA in 35% (r = 0.02, high-dose collagen WBA; r = 0.08, low-dose collagen WBA) of cases.

Conclusions

Overall agreement varied from 35 to 75%. LTA and VerifyNow demonstrated the highest agreement for P2Y12-I-response, followed by moderate agreement between LTA and WBA. LTA and AspirinWorks showed moderate agreement for aspirin response, while WBA showed the weakest agreement with both LTA and AspirinWorks. The results from this study support the continued use of LTA for monitoring dual antiplatelet therapy, with VerifyNow as an appropriate alternative for P2Y12-I-response. Integration of results obtained from these varied testing platforms with patient outcomes remains paramount for future studies.

COVID-19 patient plasma demonstrates resistance to tPA-induced fibrinolysis as measured by thromboelastography

Patients critically ill with COVID-19 are at risk for thrombotic events despite prophylactic anticoagulation. Impaired fibrinolysis has been proposed as an underlying mechanism. Our objective was to determine if fibrinolysis stimulated by tissue plasminogen activator (tPA) differed between COVID patients and controls. Plasma from 14 COVID patients on prophylactic heparin therapy was obtained and compared with heparinized plasma from 14 different healthy donors to act as controls. Kaolin activated thromboelastography with heparinase was utilized to obtain baseline measurements and then repeated with the addition of 4 nM tPA. Baseline fibrinogen levels were higher in COVID plasma as measured by maximum clot amplitude (43.6 ± 6.9 mm vs. 23.2 ± 5.5 mm, p < 0.0001) and Clauss assay (595 ± 135 mg/dL vs. 278 ± 44 mg/dL, p < 0.0001). With the addition of tPA, fibrinolysis at 30 min after MA (LY30%) was lower (37.9 ± 16.5% vs. 58.9 ± 18.3%, p = 0.0035) and time to 50% lysis was longer (48.8 ± 16.3 vs. 30.5 ± 15.4 min, p = 0.0053) in the COVID-19 samples. Clotting times and rate of fibrin polymerization ('R' or 'α' parameters) were largely the same in both groups. Clot from COVID patients contains a higher fibrin content compared to standard controls and shows resistance to fibrinolysis induced by tPA. These findings suggest the clinical efficacy of thrombolytics may be reduced in COVID-19 patients.

Therapeutic plasma exchange for COVID-19-associated hyperviscosity

Background

Recent data suggests an association between blood hyperviscosity and both propensity for thrombosis and disease severity in patients with COVID‐19. This raises the possibility that increased viscosity may contribute to endothelial damage and multiorgan failure in COVID‐19, and that therapeutic plasma exchange (TPE) to decrease viscosity may improve patient outcomes.

Here we sought to share our experience using TPE in the first 6 patients treated for COVID‐19‐associated hyperviscosity.

Study Design and Methods

Six critically ill COVID‐19 patients with plasma viscosity levels ranging from 2.6 to 4.2 centipoise (cP; normal range, 1.4‐1.8 cP) underwent daily TPE for 2‐3 treatments.

Results

TPE decreased plasma viscosity in all six patients (Pre‐TPE median 3.75 cP, range 2.6‐4.2 cP; Post‐TPE median 1.6 cP, range 1.5‐1.9 cP). TPE also decreased fibrinogen levels in all five patients for whom results were available (Pre‐TPE median 739 mg/dL, range 601‐1188 mg/dL; Post‐TPE median 359 mg/dL, range 235‐461 mg/dL); D‐dimer levels in all six patients (Pre‐TPE median 5921 ng/mL, range 1134‐60 000 ng/mL; Post‐TPE median 4893 ng/mL, range 620‐7518 ng/mL); and CRP levels in five of six patients (Pre‐TPE median 292 mg/L, range 136‐329 mg/L; Post‐TPE median 84 mg/L, range 31‐211 mg/L). While the two sickest patients died, significant improvement in clinical status was observed in four of six patients shortly after TPE.

Conclusions

This series demonstrates the utility of TPE to rapidly correct increased blood viscosity in patients with COVID‐19‐associated hyperviscosity. Large randomized trials are needed to determine whether TPE may improve clinical outcomes for patients with COVID‐19.

Trends and diagnostic value of D-dimer levels in patients hospitalized with coronavirus disease 2019

Coronavirus disease 2019 (COVID-19) has been associated with increased incidence of venous thromboembolic events (VTE) as well as mortality. D-dimer is a marker of fibrinolysis and has been used as a diagnostic and prognostic marker in VTE among other diseases. The purpose of our study is to describe outcomes from out center and to examine trends in D-dimer levels as it relates to VTE and mortality.Patients admitted with confirmed COVID-19 cases to Emory Healthcare from March 12, 2020 through April 6, 2020 with measured plasma D-dimer levels were included in our retrospective analysis. Relevant data about comorbidities, hospitalization course, laboratory results, and outcomes were analyzed.One hundred fifteen patients were included in our study. Mean age was 64 ± 15 years, 47 (41%) females and 84 (73%) African-American. Hypertension was present in 83 (72%) and diabetes in 60 (52%). Mean duration of hospitalization was 19 ± 11 days with 62 (54%) patients intubated (mean duration of 13 ± 8 days). VTE was diagnosed in 27 (23%) patients (mean time to diagnosis 14 ± 9 days). Median D-dimer within the first 7 days of hospitalization was higher (6450 vs. 1596 ng/mL, p < 0.001) in VTE cases compared to non-VTE cases, and was predictive of VTE (area under the curve [AUC] = 0.72, optimal threshold 2500 ng/mL) although not of mortality (AUC 0.55, P = .34). Change in D-dimer level (AUC = 0.72 P = .004) and rate of D-dimer rise (AUC = 0.75 P = .001) were also predictive of VTE, though neither predicted death (P > .05 for all). Within the first 7 days of hospitalization, peak D-dimer level of >2500 ng/mL and a rate of change exceeding 150 ng/mL/d were predictive of future diagnosis of VTE. Rise in D-dimer >2000 ng/mL within any 24 hour period through hospital day 10 had 75% sensitivity and 74% specificity for diagnosis of VTE.We found that both magnitude and rate of rise in d-dimer within the first 10 days of hospitalization are predictive of diagnosis of VTE but not mortality. These parameters may aid in identifying individuals with possible underlying VTE or at high risk for VTE, thereby guiding risk stratification and anticoagulation policies in COVID-19 patients.

Controlled Multifactorial Coagulopathy: Effects of Dilution, Hypothermia, and Acidosis on Thrombin Generation In Vitro

BACKGROUND

Coagulopathy and hemostatic abnormalities remain a challenge in patients following trauma and major surgery. Coagulopathy in this setting has a multifactorial nature due to tissue injury, hemodilution, hypothermia, and acidosis, the severity of which may vary. In this study, we combined computational kinetic modeling and in vitro experimentation to investigate the effects of multifactorial coagulopathy on thrombin, the central enzyme in the coagulation system.

METHODS

We measured thrombin generation in platelet-poor plasma from 10 healthy volunteers using the calibrated automated thrombogram assay (CAT). We considered 3 temperature levels (31°C, 34°C, and 37°C), 3 pH levels (6.9, 7.1, and 7.4), and 3 degrees of dilution with normal saline (no dilution, 3-fold dilution, and 5-fold dilution). We measured thrombin-generation time courses for all possible combinations of these conditions. For each combination, we analyzed 2 scenarios: without and with (15 nM) supplementation of thrombomodulin, a key natural regulator of thrombin generation. For each measured thrombin time course, we recorded 5 quantitative parameters and analyzed them using multivariable regression. Moreover, for multiple combinations of coagulopathic conditions, we performed routine coagulation tests: prothrombin time (PT) and activated partial thromboplastin time (aPTT). We compared the experimental results with simulations using a newly developed version of our computational kinetic model of blood coagulation.

RESULTS

Regression analysis allowed us to identify trends in our data (P < 10). In both model simulations and experiments, dilution progressively reduced the peak of thrombin generation. However, we did not experimentally detect the model-predicted delay in the onset of thrombin generation. In accord with the model predictions, hypothermia delayed the onset of thrombin generation; it also increased the thrombin peak time (up to 1.30-fold). Moreover, as predicted by the kinetic model, the experiments showed that hypothermia increased the area under the thrombin curve (up to 1.97-fold); it also increased the height of the thrombin peak (up to 1.48-fold). Progressive acidosis reduced the velocity index by up to 24%; acidosis-induced changes in other thrombin generation parameters were much smaller or none. Acidosis increased PT by 14% but did not influence aPTT. In contrast, dilution markedly prolonged both PT and aPTT. In our experiments, thrombomodulin affected thrombin-generation parameters mainly in undiluted plasma.

CONCLUSIONS

Dilution with normal saline reduced the amount of generated thrombin, whereas hypothermia increased it and delayed the time of thrombin accumulation. In contrast, acidosis in vitro had little effect on thrombin generation.

Anticoagulation Management and Heparin Resistance During Cardiopulmonary Bypass: A Survey of Society of Cardiovascular Anesthesiologists Members

We surveyed Society of Cardiovascular Anesthesiologists members regarding anticoagulation practices for cardiopulmonary bypass and attitudes on heparin resistance. Of 550 respondents (18.5% response rate), 74.9% (95% CI, 71.3%–78.5%) used empiric weight-based dosing of heparin, and 70.7% (95% CI, 66.9%–74.5%) targeted an activated clotting time of either 400 or 480 seconds to initiate cardiopulmonary bypass. Of note, 17.1% (95% CI, 13.9%–20.2%) of respondents reported activated clotting time targets lower than those recommended by recent 2018 Society of Thoracic Surgeons/Society of Cardiovascular Anesthesiologists/American Society of Extracorporeal Technology guidelines or failed to monitor heparin effects at all. When heparin resistance was encountered, 54.2% of respondents (95% CI, 50.0%–58.4%) administered antithrombin concentrates as a first-line therapy.

Catastrophic Intracardiac Thrombosis During Emergency Repair of an Expanding Aortic Pseudoaneurysm: A Case Report

Catastrophic thrombosis is a rare but frequently fatal event following complex cardiac surgery. It is most often encountered following separation from cardiopulmonary bypass (CPB) and reversal of heparin anticoagulation, and somewhat paradoxically, at the time when bleeding from post-CPB coagulopathy is being treated. We report the case of a 41-year-old female taken to the operating room for repair of an expanding ascending aortic pseudoaneurysm. Following a prolonged operation, she developed intracardiac thrombus during transfusion of hemostatic blood products and procoagulant agents. Potential contributing factors are discussed.

Platelet function, but not thrombin generation, is impaired in acute normovolemic hemodilution (ANH) blood

STUDY OBJECTIVE

We investigated the coagulation changes that might occur in acute normovolemic hemodilution (ANH) blood over several hours during cardiac surgery requiring cardiopulmonary bypass.

DESIGN

This study was a prospective observational study.

SETTING

This study took place at a university teaching hospital.

PATIENTS

This study included 26 patients, either ASA 3 or 4 and without known coagulation disorders, undergoing cardiac surgery. Patients were included if the use of cardiopulmonary bypass was expected to reach 2.5 h.

INTERVENTIONS

ANH blood was collected into CPDA-1 collection bags before systemic heparinization. Samples were taken directly from the bags at time of collection and reinfusion to assess changes in platelet and thrombin generation parameters.

MEASUREMENTS

Whole blood from citrated tubes was used immediately for rotational thromboelastometry and platelet aggregometry analyses. Thrombin generation was assessed using calibrated automated thrombography with platelet poor plasma.

MAIN RESULTS

Despite no significant change in platelet count over the ANH storage period, there was significant degradation in platelet function as measured by thrombin receptor activating peptide stimulation on Mulltiplate™ analysis and maximum clot formation on ROTEM™ EXTEM. Notably, there was no change in the ability to generate thrombin.

CONCLUSIONS

Little data exists regarding the quality of coagulation factors in autologous blood. Our study confirms ANH collection results in decreased platelet aggregation with TRAP stimulation; however, this is not appreciated with ADP stimulation. Thrombin generation capacity remains preserved.

Safety of Intranasal Ketamine for Reducing Uncontrolled Cancer-Related Pain: Protocol of a Phase I/II Clinical Trial

Background

Approximately 12 million Americans are affected with cancer. Of these, 53% experience pain at all stages of cancer. Pain may remain uncontrolled despite high-dose opioid therapy, and opioids have many well-documented harmful side effects. Intranasal ketamine has been shown to be effective in controlling breakthrough noncancer pain in a double-blind randomized control trial (DBRCT) by Carr et al in 2003 as well as to help with depression in a DBRCT by Lapidus et al in 2014. We seek to obtain preliminary data on the safety, feasibility, and utility of this novel technique for the treatment of uncontrolled cancer pain.

Objective

This study aimed to obtain preliminary data via a clinical trial addressing the safety, feasibility, pharmacokinetics, and pharmacodynamics of intranasal ketamine. These initial findings will be applied to a subsequent trial to determine the effectiveness and associated toxicities of ketamine in a larger sample of cancer patients and to address the compelling need to identify new, successful management therapies for cancer pain.

Methods

This is an institutional review board– and investigational new drug–approved, prospective phase I/II trial to investigate the safety and use of intranasal ketamine in patients with uncontrolled pain related to cancer or cancer treatment. Informed consent will be obtained prior to all study procedures. All patients will be assigned to the same investigational treatment arm. After patient selection via inclusion/exclusion criteria, patients will be seen over 5 visits, with each visit conducted 2-7 days apart. Patients will be administered ketamine on visits 1-4 and monitored for 240 minutes with continuous pulse oximetry and regular blood pressure checks. Blood samples as well as patient-reported outcomes will be collected at set time points at baseline and after drug delivery. Patients will receive 10 mg intranasal ketamine on visit 1, 10 mg intravenous ketamine on visit 2, 30 mg intranasal ketamine on visit 3, and 50 mg intranasal ketamine on visit 4. On visit 5, an addition blood sample will be drawn.

Results

As of March 2019, enrollment is in progress, and a total of 7 subjects have completed the study. Enrollment is expected to be completed by April 2019. Final data analysis will commence soon after, and the results are expected to be submitted for publication in 2019.

Conclusions

If intranasal ketamine can be utilized for pain control in cancer patients, it could provide superior analgesia and better quality of life, without the risk of significant respiratory depression and constipation associated with opioid medications. These findings will be an important initial step toward testing the effectiveness of intranasal ketamine as a nonopioid medication for cancer pain and as potential maintenance outpatient therapy.

Trial Registration

ClinicalTrials.gov NCT03146806; https://clinicaltrials.gov/ct2/show/NCT03146806.

International Registered Report Identifier (IRRID)

DERR1-10.2196/12125

Effects of blood storage age on immune, coagulation, and nitric oxide parameters in transfused patients undergoing cardiac surgery

BACKGROUND

Retrospective studies suggested that storage age of RBCs is associated with inflammation and thromboembolism. The Red Cell Storage Duration Study (RECESS) trial randomized subjects undergoing complex cardiac surgery to receive RBCs stored for shorter versus longer periods, and no difference was seen in the primary outcome of change in multiple organ dysfunction score.

STUDY DESIGN AND METHODS

In the current study, 90 subjects from the RECESS trial were studied intensively using a range of hemostasis, immunologic, and nitric oxide parameters. Samples were collected before transfusion and on Days 2, 6, 28, and 180 after transfusion.

RESULTS

Of 71 parameters tested, only 4 showed a significant difference after transfusion between study arms: CD8+ T-cell interferon-γ secretion and the concentration of extracellular vesicles bearing the B-cell marker CD19 were higher, and plasma endothelial growth factor levels were lower in recipients of fresh versus aged RBCs. Plasma interleukin-6 was higher at Day 2 and lower at Days 6 and 28 in recipients of fresh versus aged RBCs. Multiple parameters showed significant modulation after surgery and transfusion. Most analytes that changed after surgery did not differ based on transfusion status. Several extracellular vesicle markers, including two associated with platelets (CD41a and CD62P), decreased in transfused patients more than in those who underwent surgery without transfusion.

CONCLUSIONS

Transfusion of fresh versus aged RBCs does not result in substantial changes in hemostasis, immune, or nitric oxide parameters. It is possible that transfusion modulates the level of platelet-derived extracellular vesicles, which will require study of patients randomly assigned to receipt of transfusion to define.

Antithrombin: anti-inflammatory properties and clinical applications

Many humoral and cellular components participate in bidirectional communication between the coagulation and inflammation pathways. Natural anticoagulant proteins, including antithrombin (AT), tissue factor pathway inhibitor, and protein C, suppress proinflammatory mediators. Conversely, inflammation blunts anticoagulant activity and, when uncontrolled, promotes systemic inflammation-induced coagulation, such as those that occur in disseminated intravascular coagulation and severe sepsis. This review discusses the mechanisms of action and clinical use of AT concentrate in critically ill patients and in the settings of perioperative anticoagulation management for surgery and obstetrics. AT is a serine protease inhibitor with broad anticoagulant activity and potent anti-inflammatory properties. In clinical conditions associated with hereditary or acquired AT deficiency, administration of AT concentrate has been shown to restore proper haemostasis and attenuate inflammation. Of note, AT modulates inflammatory responses not only by inhibiting thrombin and other clotting factors that induce cytokine activity and leukocyte-endothelial cell interaction, but also by coagulation-independent effects, including direct interaction with cellular mediators of inflammation. An increasing body of evidence suggests that AT concentrate may be a potential therapeutic agent in certain clinical settings associated with inflammation. In addition to the well-known anticoagulation properties of AT for the treatment of hereditary AT deficiency, AT also possesses noteworthy anti-inflammatory properties that could be valuable in treating acquired AT deficiency, which often result in thrombotic states associated with an inflammatory component.

Anticoagulation management associated with extracorporeal circulation

The use of extracorporeal circulation requires anticoagulation to maintain blood fluidity throughout the circuit, and to prevent thrombotic complications. Additionally, adequate suppression of hemostatic activation avoids the unnecessary consumption of coagulation factors caused by the contact of blood with foreign surfaces. Cardiopulmonary bypass represents the greatest challenge in this regard, necessitating profound levels of anticoagulation during its conduct, but also quick, efficient reversal of this state once the surgical procedure is completed. Although extracorporeal circulation has been around for more than half a century, many questions remain regarding how to best achieve anticoagulation for it. Although unfractionated heparin is the predominant agent used for cardiopulmonary bypass, the amount required and how best to monitor its effects are still unresolved. This review discusses the use of heparin, novel anticoagulants, and the monitoring of anticoagulation during the conduct of cardiopulmonary bypass.

Bleeding and management of coagulopathy

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

Coagulopathy After Cardiopulmonary Bypass in Jehovah’s Witness Patients: Management of Two Cases Using Fractionated Components and Factor VIIa

BACKGROUND

Changes in the Jehovah's Witness (JW) blood refusal policy now give members the personal choice to accept certain processed fractions of blood, such as factor concentrates and cryoprecipitate.

METHODS

Two JW patients undergoing complex aortic surgery who developed severe microvascular bleeding after prolonged use of cardiopulmonary bypass were treated with recombinant activated factor VII, cryoprecipitate, and antithrombin concentrate.

RESULTS

Cardiopulmonary bypass-induced coagulopathy was successfully treated, allowing chest closure without evidence of thrombotic complications.

CONCLUSIONS

Processed blood fractions can be a valuable adjuvant to drugs when treating bleeding in JW patients.