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.

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.

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.

Detection of cellular traction forces via the force-triggered Cas12a-mediated catalytic cleavage of a fluorogenic reporter strand.

Molecular forces generated by cell receptors are infrequent and transient, and hence difficult to detect. Here we report an assay that leverages the CRISPR-associated protein 12a (Cas12a) to amplify the detection of cellular traction forces generated by as few as 50 adherent cells. The assay involves the immobilization of a DNA duplex modified with a ligand specific for a cell receptor. Traction forces of tens of piconewtons trigger the dehybridization of the duplex, exposing a cryptic Cas12-activating strand that sets off the indiscriminate Cas12-mediated cleavage of a fluorogenic reporter strand. We used the assay to perform hundreds of force measurements using human platelets from a single blood draw to extract individualized dose-response curves and half-maximal inhibitory concentrations for a panel of antiplatelet drugs. For seven patients who had undergone cardiopulmonary bypass, platelet dysfunction strongly correlated with the need for platelet transfusion to limit bleeding. The Cas12a-mediated detection of cellular traction forces may be used to assess cell state, and to screen for genes, cell-adhesion ligands, drugs or metabolites that modulate cell mechanics.

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.

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.

COVID-19 patient fibrinogen produces dense clots with altered polymerization kinetics, partially explained by increased sialic acid.

BACKGROUND: Thrombogenicity is a known complication of COVID-19, resulting from SARS-CoV-2 infection, with significant effects on morbidity and mortality. OBJECTIVE: We aimed to better understand the effects of COVID-19 on fibrinogen and the resulting effects on clot structure, formation, and degradation. METHODS: Fibrinogen isolated from COVID-19 patients and uninfected subjects was used to form uniformly concentrated clots (2 mg/ml), which were characterized using confocal microscopy, scanning electron microscopy, atomic force microscopy, and endogenous and exogenous fibrinolysis assays. Neuraminidase digestion and subsequent NANA assay were used to quantify sialic acid residue presence; clots made from the desialylated fibrinogen were then assayed similarly to the original fibrinogen clots. RESULTS: Clots made from purified fibrinogen from COVID-19 patients were shown to be significantly stiffer and denser than clots made using fibrinogen from noninfected subjects. Endogenous and exogenous fibrinolysis assays demonstrated that clot polymerization and degradation dynamics were different for purified fibrinogen from COVID-19 patients compared with fibrinogen from noninfected subjects. Quantification of sialic acid residues via the NANA assay demonstrated that SARS-CoV-2-positive fibrinogen samples contained significantly more sialic acid. Desialylation via neuraminidase digestion resolved differences in clot density. Desialylation did not normalize differences in polymerization, but did affect rate of exogenous fibrinolysis. DISCUSSION: These differences noted in purified SARS-CoV-2-positive clots demonstrate that structural differences in fibrinogen, and not just differences in gross fibrinogen concentration, contribute to clinical differences in thrombotic features associated with COVID-19. These structural differences are at least in part mediated by differential sialylation.

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.

A dose-escalation clinical trial of intranasal ketamine for uncontrolled cancer-related pain.

STUDY OBJECTIVE: The objective of our study was to determine safety and pharmacology (pharmacokinetics and preliminary efficacy) of intranasal (IN) ketamine for uncontrolled cancer-related pain. DESIGN: Dose escalation clinical trial. SETTING: Outpatient. PATIENTS: Ten adult patients with uncontrolled cancer-related pain. INTERVENTION: Each patient received escalating doses of ketamine over four visits, each 2-5 days apart: 10 mg IN at visit 1, 10 mg intravenous (IV) at visit 2, 30 mg IN at visit 3, and 50 mg IN at visit 4. MEASUREMENTS: Pain was measured before and after drug administration for up to 4 h using the 11 point (0-10) Numerical Pain Rating Scale (NPRS). MAIN RESULTS: All subjects had advanced cancer, with intractable pain, despite being on moderate dosage of opioids. There was a statistically significant reduction in median NPRS by 1.5 (1-4), 3 (2-3), and 4 (3-5) points at 60 min after receiving the medication and remained decreased by 1.5 (1-2), 2 (1-2) and 1 (1-4) points at the end of the study visit (240 min) with the 10 mg, 30 mg and 50 mg IN dosage, respectively. The median percentage of maximal pain relief being 22.5 (16.6-71.5), 65.5 (40-100), and 69.25 (50-100) for 10 mg, 30 mg and 50 mg IN dosage, respectively and 100 (75-100) with 10 mg IV dose. All side effects (nausea and feeling of unreality) resolved by the end of each study visit. No severe adverse events occurred. CONCLUSION: In this single-institution study, all dosages of IN ketamine administered in the study (10, 30, and 50 mg) provided significant pain relief for intractable cancer-related pain and were well tolerated. The 50 mg dose provided maximal pain relief without major side effects. Further study focused on repeated administration efficacy and safety for cancer-related pain is warranted.

Clinical Outcomes of Critically III Patients with COVID-19 by Race.

BACKGROUND: Studies of COVID-19 have shown that African Americans have been affected by the virus at a higher rate compared to other races. This cohort study investigated comorbidities and clinical outcomes by race among COVID-19 patients admitted to the intensive care unit. METHODS: This is a case series of critically ill patients admitted with COVID-19 to an academic healthcare system in Atlanta, Georgia. The study included all critically ill hospitalized patients between March 6, 2020, and May 5, 2020. Clinical outcomes during hospitalization included mechanical ventilation, renal replacement therapy, and mortality stratified by race. RESULTS: Of 288 patients included (mean age, 63 ± 16 years; 45% female), 210 (73%) were African American. African Americans had significantly higher rates of comorbidities compared to other races, including hypertension (80% vs 59%, P = 0.001), diabetes (49% vs 34%, P = 0.026), and mean BMI (33 kg/m2 vs 28 kg/m2, P < 0.001). Despite African Americans requiring continuous renal replacement therapy during hospitalization at higher rates than other races (27% vs 13%, P = 0.011), rates of intubation, intensive care unit length of stay, and overall mortality (30% vs 24%, P = 0.307) were similar. CONCLUSION: This racially diverse series of critically ill COVID-19 patients shows that despite higher rates of comorbidities at hospital admission in African Americans compared with other races, there was no significant difference in mortality.

Identification of coagulation factor IX variants with enhanced activity through ancestral sequence reconstruction.

Orthologous proteins contain sequence disparity guided by natural selection. In certain cases, species-specific protein functionality predicts pharmacological enhancement, such as greater specific activity or stability. However, immunological barriers generally preclude use of nonhuman proteins as therapeutics, and difficulty exists in the identification of individual sequence determinants among the overall sequence disparity. Ancestral sequence reconstruction (ASR) represents a platform for the prediction and resurrection of ancient gene and protein sequences. Recently, we demonstrated that ASR can be used as a platform to facilitate the identification of therapeutic protein variants with enhanced properties. Specifically, we identified coagulation factor VIII (FVIII) variants with improved specific activity, biosynthesis, stability, and resistance to anti-human FVIII antibody-based inhibition. In the current study, we resurrected a panel of ancient mammalian coagulation factor IX (FIX) variants with the goal of identifying improved pharmaceutical candidates. One variant (An96) demonstrated 12-fold greater FIX activity production than human FIX. Addition of the R338L Padua substitution further increased An96 activity, suggesting independent but additive mechanisms. after adeno-associated virus 2 (AAV2)/8-FIX gene therapy, 10-fold greater plasma FIX activity was observed in hemophilia B mice administered AAV2/8-An96-Padua as compared with AAV2/8-human FIX-Padua. Furthermore, phenotypic correction conferred by the ancestral variant was confirmed using a saphenous vein bleeding challenge and thromboelastography. Collectively, these findings validate the ASR drug discovery platform as well as identify an ancient FIX candidate for pharmaceutical development.

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.

Validation of an admission coagulation panel for risk stratification of COVID-19 patients.

BACKGROUND: There is limited data on the markers of coagulation and hemostatic activation (MOCHA) profile in Coronavirus disease 2019 (COVID-19) and its ability to identify COVID-19 patients at risk for thrombotic events and other complications. METHODS: Hospitalized patients with confirmed SARS-COV-2 from four Atlanta hospitals were included in this observational cohort study and underwent admission testing of MOCHA parameters (plasma d-dimer, prothrombin fragment 1.2, thrombin-antithrombin complex, fibrin monomer). Clinical outcomes included deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke, access line thrombosis, ICU admission, intubation and mortality. MAIN RESULTS: Of 276 patients (mean age 59 ± 6.4 years, 47% female, 62% African American), 45 (16%) had a thrombotic endpoint. Each MOCHA parameter was independently associated with a thrombotic event (p<0.05) and ≥ 2 abnormalities was associated with thrombotic endpoints (OR 3.3, 95% CI 1.2-8.8) as were admission D-dimer ≥ 2000 ng/mL (OR 3.1, 95% CI 1.5-6.6) and ≥ 3000 ng/mL (OR 3.6, 95% CI 1.6-7.9). However, only ≥ 2 MOCHA abnormalities were associated with ICU admission (OR 3.0, 95% CI 1.7-5.2) and intubation (OR 3.2, 95% CI 1.6-6.4). MOCHA and D-dimer cutoffs were not associated with mortality. MOCHA with <2 abnormalities (26% of the cohort) had 89% sensitivity and 93% negative predictive value for a thrombotic endpoint. CONCLUSIONS: An admission MOCHA profile is useful to risk-stratify COVID-19 patients for thrombotic complications and more effective than isolated d-dimer for predicting risk of ICU admission and intubation.

Fibrinolysis Shutdown and Thrombosis in a COVID-19 ICU.

ABSTRACT: The coronavirus disease (COVID-19) pandemic has threatened millions of lives worldwide with severe systemic inflammation, organ dysfunction, and thromboembolic disease. Within our institution, many critically ill COVID-19-positive patients suffered major thrombotic events, prompting our clinicians to evaluate hypercoagulability outside of traditional coagulation testing.We determined the prevalence of fibrinolysis shutdown via rotational thromboelastometry (ROTEM, Instrumentation Laboratories, Bedford, Mass) in patients admitted to the intensive care unit over a period of 3 weeks. In 25 patients who had a ROTEM test, we found that 11 (44%) met criteria for fibrinolysis shutdown. Eight of 9 (73%) of the VTE patients met criteria for fibrinolysis shutdown.Given the high rate of fibrinolysis shutdown in these patients, our data support using viscoelastic testing to evaluate for the presence of impaired fibrinolysis. This may help identify patient subsets who might benefit from the administration of fibrinolytics.

Feasibility of Auricular Field Stimulation in Fibromyalgia: Evaluation by Functional Magnetic Resonance Imaging, Randomized Trial.

OBJECTIVE: To evaluate the feasibility of recruitment, preliminary efficacy, and acceptability of auricular percutaneous electrical nerve field stimulation (PENFS) for the treatment of fibromyalgia in veterans, using neuroimaging as an outcome measure and a biomarker of treatment response. DESIGN: Randomized, controlled, single-blind. SETTING: Government hospital. SUBJECTS: Twenty-one veterans with fibromyalgia were randomized to standard therapy (ST) control or ST with auricular PENFS treatment. METHODS: Participants received weekly visits with a pain practitioner over 4 weeks. The PENFS group received reapplication of PENFS at each weekly visit. Resting-state functional connectivity magnetic resonance imaging (rs-fcMRI) data were collected within 2 weeks prior to initiating treatment and 2 weeks following the final treatment. Analysis of rs-fcMRI used a right posterior insula seed. Pain and function were assessed at baseline and at 2, 6, and 12 weeks post-treatment. RESULTS: At 12 weeks post-treatment, there was a nonsignificant trend toward improved pain scores and significant improvements in pain interference with sleep among the PENFS treatment group as compared with the ST controls. Neuroimaging data displayed increased connectivity to areas of the cerebellum and executive control networks in the PENFS group as compared with the ST control group following treatment. CONCLUSIONS: There was a trend toward improved pain and function among veterans with fibromyalgia in the ST + PENFS group as compared with the ST control group. Pain and functional outcomes correlated with altered rs-fcMRI network connectivity. Neuroimaging results differed between groups, suggesting an alternative underlying mechanism for PENFS analgesia.