Protamine dose to neutralize heparin at the completion of cardiopulmonary bypass can be reduced significantly without affecting post-operative bleeding.

BACKGROUND: Systemic anticoagulation with heparin during cardiopulmonary bypass (CPB) should be neutralized by protamine administration to restore normal hemostasis. Our previous study showed the protamine-to-heparin ratio (P-to-H) of 1:1 (1 mg protamine:100 IU circulating heparin; 1.0 Ratio) is likely an overestimation. Thus, we reduced the P-to-H in the HMS Plus Hemostasis Management System to 0.9:1 (0.9 Ratio) for 5 months and then to 0.8:1 (0.8 Ratio). We monitored post-operative (post-op) bleeding in the setting of reduced protamine dose (PD). METHODS: We performed a retrospective study of 632 patients (209 for the 1.0 Ratio, 211 for 0.9 Ratio, 212 for 0.8 Ratio group) who underwent cardiac surgery to measure the reduction of PD and how it affects 24-hour (24 h) post-op chest tube output. We also analyzed the entire data set to explore whether further reduction of P-to-H is warranted. RESULTS: While there was no difference in the indexed heparin dose among the three groups, we achieved a significant reduction in the indexed actual protamine dose (APDi) by 24% (0.9 Ratio) and 31% (0.8 Ratio) reductions compared to the 1.0 Ratio group. On average, APDi was 88 ± 22, 67 ± 18, and 61 ± 15 mg/m2 in the 1.0, 0.9, and 0.8 Ratio groups, respectively. We found no significant difference in 24 h post-op bleeding among the three groups. CONCLUSION: 1.0 Ratio at the completion of CPB is likely an excessive administration of protamine. With the stepwise reduction of PD, we observed no increase in post-op bleeding, which may indicate that no meaningful increase in heparin rebound occurred. In addition, further analysis of the entire data set demonstrates that a 0.75 Ratio is likely sufficient to neutralize the heparin completely.

Bivalirudin for cardiopulmonary bypass in a patient with heparin allergy.

BACKGROUND: Hypersensitivity reactions to heparin are uncommon conditions but pose a serious clinical problem for patients requiring cardiopulmonary bypass. Bivalirudin is a reversible direct thrombin inhibitor that can be used instead of heparin. CASE REPORT: A 49-year-old male patient was admitted to our hospital for coronary artery bypass graft operation with mitral insufficiency and tricuspid valve insufficiency. Heparin allergy was confirmed by skin biopsy and skin tests. Due to this allergy, we used bivalirudin (Bivacard VEM drug, Turkey) during the surgery. A loading dose of 1.0 mg/kg (100 mg) bivalirudin was administered through the central line and a continuous infusion of 2.5 mg/kg/h of the anticoagulant was initiated following the approved protocol. Serial ACTs were obtained at 15-minute intervals during the procedure and the measurements were 330s, 320s, 350s, 360s, and 340s consecutively. Additional boluses of 0.5 mg/kg (50 mg) were administered for each measurement. Left anterior descending, obtuse marginal arteries and the right coronary artery were grafted with the left internal mammary and saphenous veins. Also, mitral valve replacement with St Jude mechanical heart valve and tricuspid ring annuloplasty was performed with Medtronic Duran ring. After the surgery, the patient had an uneventful period in the postoperative intensive care unit with a total of 600ml and 300ml chest tube drainage for two days and was discharged on the 7th day. CONCLUSION: Alternative anticoagulation strategies are needed for cardiopulmonary bypass in patients unable to use heparin. Bivalirudin may be recommended as a viable alternative anticoagulant in patients with heparin allergy during cardiopulmonary bypass. However, each patient should be evaluated individually and it should not be forgotten that more than recommended doses may be needed.

The Effect of the Intra-Arterial Heparin Flushing (IAHF) Procedure on Hearing Threshold in Sensorineural Hearing Loss Patients.

Background: Sensorineural hearing loss (SNHL) is a frequent problem in Indonesia but its treatment is still limited. This type of hearing loss is related to oxidative stress and decreased vascularization, which can damage the hair cell. The intra-arterial heparin flushing (IAHF) is a procedure that can recover circulation and its agent, namely heparin, also has antioxidant activity. Therefore, the IAHF procedure has the potential to improve hearing function and can be considered an alternative therapy for SNHL. Objective: The study evaluates the effect of the IAHF on hearing improvement based on the difference in hearing threshold values before and after the procedure. Methods: This experimental study used a Pretest-Posttest One-Group Only design. A total of 17 patients with sensorineural hearing loss who met inclusion and exclusion criteria were subjected to pure tone audiometry tests before and 4 hours after the IAHF procedure. The mean difference in hearing threshold was analyzed using paired Students t-test for normally distributed data and Wilcoxon for non-normally distributed data. Results: There was a decrease in the means of hearing threshold in the right and left ear 4 hours after the IAHF procedure. However, based on the paired Students t-test, there was not a significant difference in hearing threshold before and after the procedure (p-value > 0.05). Conclusion: There was hearing threshold improvement 4 hours after the IAHF procedure. This study showed that the IAHF procedure can have a therapeutic effect on sensorineural hearing loss patients.

Efficacy and safety of inhaled heparin in asthmatic and chronic obstructive pulmonary disease patients: a systematic review and a meta-analysis.

Asthma and chronic obstructive pulmonary disease (COPD) are prevalent chronic respiratory disorders that cause significant morbidity and mortality. Some studies evaluated the use of inhaled unfractionated heparin (UFH) in the treatment of asthma and COPD. We aimed to synthesize the available evidence for the efficacy and safety of inhaled heparin in improving lung functions among asthmatic and COPD patients. A comprehensive search was performed using Pubmed, Embase, EBSCO, Scopus, Web of Science, Cochrane CENTRAL, WHO Clinical trials, clinicaltrials.gov, Iranian Clinical trials, Google Scholar, Research Gate, ProQuest Thesis, OVID, and medRxiv databases. Two independent reviewers included all pertinent articles according to PRISMA guidelines, and extract data independently. The two reviewers checked the quality of studies using the ROB2 tool. To determine the pooled effect estimate of the efficacy and safety of inhaled heparin, a meta-analysis was carried out using the R programming language. Publication bias was evaluated using Egger's regression test. The heterogeneity was explained using a meta-regression, and the quality of evidence was assessed by the GRADE approach. Twenty-six studies with a total of 581 patients were included in the qualitative analysis and 16 in the meta-analysis. The primary outcome was treatment success (improvement of lung function) that was measured by standardized mean differences (SMD) of the forced expiratory volume per second (FEV1) either per ml or percentage. Heparin has a large effect on both FEV1% and FEV1 ml when compared to the control group (SMD 2.7, 95% CI 1.00; 4.39; GRADE high, SMD 2.12, 95% CI - 1.49; 5.72: GRADE moderate, respectively). Secondary outcomes are other lung functions improving parameters such as PC20 (SMD 0.91, 95% CI - 0.15; 1.96). Meta-regression and subgroup analysis show that heparin type, dose, year of publication, study design, and quality of studies had a substantial effect. Regarding safety, inhaled heparin showed a good coagulation profile and mild tolerable side effects. Inhaled heparin showed improvement in lung functions either alone or when added to standard care. More large parallel RCTs are needed including COPD patients, children, and other types, and stages of asthmatic patients.

Direct Oral Anticoagulants Affect Activated Clotting Time During and Bleeding Events After Percutaneous Coronary Intervention.

Inappropriately high activated clotting time (ACT) during percutaneous coronary intervention (PCI) is associated with an increased risk of bleeding events. However, whether the prescription of direct oral anticoagulants (DOACs) affects ACT kinetics during heparin use and adverse clinical events in patients who underwent PCI remains unclear. We aimed to evaluate the relations between ACT changes during and adverse clinical events after PCI in patients who were prescribed DOAC. This observational study included 246 patients who underwent PCI at the 2 cardiovascular centers who were not receiving warfarin and whose ACT was recorded immediately before and 30 minutes after injection of unfractionated heparin. Patients were divided into 2 groups according to DOAC prescription at the time of the index PCI: DOAC users (n = 31) and nonusers (n = 215). Any bleeding and systemic thromboembolic events were investigated until 30 days after PCI. The average age of this population was 70.5 years, and 66.3% were male. Average ACT was significantly higher in DOAC users than nonusers both before and 30 minutes after unfractionated heparin induction (157.2 ± 30.1 vs 131.8 ± 25.1 seconds, p <0.001; 371.1 ± 122.2 vs 308.3 ± 82.2 seconds, p <0.001; respectively). The incidence of systemic thromboembolism after PCI was low and comparable between the 2 groups (0% vs 3.7%, p = 0.60). However, the rate of any bleeding event was significantly higher in DOAC users than in nonusers (16.1% vs 4.7%, p = 0.028). Patients receiving DOAC have higher ACT during PCI and higher incidence of bleeding events than those not receiving DOAC.

The effect of bivalirudin on coagulation function in male patients with coronary heart disease undergoing percutaneous coronary intervention.

Aim of this study was to explore the effect of bivalirudin on coagulation function with the treatment of percutaneous coronary intervention (PCI) in male coronary heart disease (CHD) patients. There were 90 male CHD cases treated with PCIas study object and were randomly divided into bivalirudin and unfractionated heparin group (n=45). Unfractionated heparin group patients were given unfractionated heparin and bivalirudin group cases were treated with bivalirudin. Activated clotting time (ACT), thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fib), platelet count (PLT) were determined and the major adverse cardiovascular events (MACCE) were observed in two group patients. There was no significant (p<0.05) difference with ACT, TT, PT, PLT, APTT and Fib between the two groups before and after 6h, 24h and 72h of operation. The incidence of stent thrombosis and general bleeding with in 24h after PCI in bivalirudin group was lower than in heparin group. After 13 months of follow-up, there was no significant (p<0.05) difference in the incidence of MACCE between the two groups. Compared with the treatment of unfractionated heparin in CHD patients after PCI in 24h, the bivalirudin had more remarkable effect, such as rapid onset, short half-life, lower incidence of thrombosis and bleeding.

The immunology of PF4 polyanion interactions.

PURPOSE OF REVIEW: Platelet factor 4 (PF4, CXCL4), the most abundant α-granule platelet-specific chemokine, forms tetramers with an equatorial ring of high positive charge that bind to a wide range of polyanions, after which it changes conformation to expose antigenic epitopes. Antibodies directed against PF4 not only help to clear infection but can also lead to the development of thrombotic disorders such as heparin-induced thrombocytopenia (HIT) and vaccine-induced thrombocytopenia and thrombosis (VITT). This review will outline the different mechanisms through which PF4 engagement with polyanions combats infection but also contributes to the pathogenesis of inflammatory and thrombotic disease states. RECENT FINDINGS: Recent work has shown that PF4 binding to microbial polyanions may improve outcomes in infection by enhancing leukocyte-bacterial binding, tethering pathogens to neutrophil extracellular traps (NETs), decreasing the thrombotic potential of NET DNA, and modulating viral infectivity. However, PF4 binding to nucleic acids may enhance their recognition by innate immune receptors, leading to autoinflammation. Lastly, while HIT is induced by platelet activating antibodies that bind to PF4/polyanion complexes, VITT, which occurs in a small subset of patients treated with COVID-19 adenovirus vector vaccines, is characterized by prothrombotic antibodies that bind to PF4 alone. SUMMARY: Investigating the complex interplay of PF4 and polyanions may provide insights relevant to the treatment of infectious disease while also improving our understanding of the pathogenesis of thrombotic disorders driven by anti-PF4/polyanion and anti-PF4 antibodies.

Laboratory and demographic predictors of functional assay positive status in suspected heparin-induced thrombocytopenia: A multicenter retrospective cohort study.

Heparin-induced thrombocytopenia (HIT) is an antibody-mediated immune response against platelet factor 4 (PF4) bound to heparin anticoagulants. A priori identification of patients at-risk for HIT remains elusive and a number of risk factors have been identified, but these associations and their effect sizes have limited validation in large cohorts of suspected HIT patients. The aim of this study was to investigate existing anti-PF4/heparin antibody thresholds and model the relationship of demographic variables and anti-PF4/heparin antibody levels with functional assay positivity across multiple institutions in the absence of detailed clinical data. In a large collection of suspected HIT patients (n = 8904), we tested for associations between laboratory and demographic variables and functional assay positive status as well as anti-PF4/heparin antibody levels. We also tested for correlation between IgG-specific and polyspecific (IgG/IgA/IgM) anti-PF4/heparin antibody values and their ability to predict functional assay positive status using area under the receiver operating characteristic (AUROC). Logistic regression identified increasing anti-PF4/heparin antibody OD levels (OR = 51.84 [37.27-74.34], p < 2.0 × 10-16) and female sex (OR = 1.47 [1.19-1.82], p = 3.5 × 10-4) as risk factors for positive functional assay in the largest cohort with consistent effect sizes in two other cohorts. In a subset of 1175 patients, polyspecific and IgG-specific anti-PF4/heparin antibody values were heterogeneous (mean coefficient of variation = 31.9 %), but strongly correlated (rho = 0.878; p < 2 × 10-16) with similar prediction of functional assay positivity (polyspecific AUROC = 0.976 and IgG-specific AUROC = 0.980). Thus, we recapitulate previously identified risk factors of functional assay positivity, providing precise effect sizes in a large observational population of suspected HIT patients. Our data reinforce the necessity of functional assay confirmation and suggest that, despite heterogeneity, polyspecific and IgG-specific anti-PF4/heparin antibody assays predict functional assay positive status similarly, even in the absence of 4Ts scores and detailed clinical data.

Effects of low-dose intravenous heparin therapy in aneurysmal subarachnoid hemorrhage: a randomized controlled clinical trial protocol.

BACKGROUND: Heparin anticoagulation therapy is a widely used method to prevent cerebral vasospasm (CV) and venous thrombosis in patients with subarachnoid hemorrhage caused by ruptured cerebral aneurysms. Subcutaneous heparin injection is considered safe and effective, whereas continuous intravenous heparin infusion is still being debated due to the risk of bleeding. Although most retrospective studies have confirmed the safety and effectiveness of unfractionated heparin (UFH) after aneurysm embolization therapy and its ability to reduce CV, there is still no randomized clinical trial comparing UFH and subcutaneous low-molecular-weight heparin (LMWH) injection in this population. Therefore, this study aims to compare the clinical outcomes associated with these two treatment approaches. METHODS: The study is an open-label, single-center, randomized controlled trial and aims to recruit 456 patients, with 228 patients in each group. The primary outcome was CV; the second outcomes measures are occurrence of bleeding events, ischemic events, heparin-induced thrombocytopenia, deep vein thrombosis, cerebral venous circulation time, brain edema score, and hydrocephalus incidence. ETHICS AND DISSEMINATION: This study protocol obtained ethical approval from the Ethics Committee of Baoan People's Hospital, Shenzhen, Guangdong (approval number: BYL20220805). This work will be published in peer-reviewed international medical journals and presented at medical conferences. TRIAL REGISTRATION: ClinicalTrials ID: NCT05696639. Registered on March 30, 2023.

[Efficacy of arteriovenous argatroban versus heparin flush anticoagulation after cardiovascular surgery].

Objective: To compare the effects of arteriovenous argatroban and heparin flushes on platelet count and assess the occurrence of heparin-induced thrombocytopenia (HIT) and other complications in patients undergoing cardiovascular surgeries. Methods: A single-center, prospective randomized control study was conducted. Patients who underwent cardiovascular surgery at Fuwai Hospital, Chinese Academy of Medical Sciences from March to December 2019 were randomly divided into the argatroban group (250 ml normal saline plus 2.5 mg of argatroban) and the heparin group (250 ml normal saline plus 10 mg of heparin). Platelet count, hemorrhage, and thrombosis were assessed. The 4T scores of HIT, the incidences of HIT and other complications were also evaluated. Results: A total of 491 patients (307 males and 184 females) were included in the study, with a mean age of (52.3±13.7) years. There were 245 cases in the argatroban group and 246 cases in the heparin group, respectively. There was no statistically significant difference in the preoperative platelet count between the argatroban and heparin groups [198.0 (161.0, 248.0)×109/L vs 194.0 (157.2, 243.8)×109/L, P=0.498]. Likewise, there were no statistically significant differences in the platelet count between the argatroban and heparin groups at 12 h, 1 day, and 5 days after operation [127.0 (100.0, 154.0)×109/L vs 121.5 (90.2, 149.0)×109/L, 126.0 (97.0, 162.0)×109/L vs 123.5 (88.0, 151.0)×109/L, 168.0 (130.0, 215.0) ×109/L vs 161.0 (101.0, 210.5)×109/L] (repeated measures ANOVA between groups: F=3.327, P=0.069; time comparison: F=532.523, P<0.001; time interaction between groups: F=0.675, P=0.512). The proportion of 4T scores of medium and high scores (≥4)[9.8% (24/245) vs 10.6% (26/246), P=0.777] and incidence of HIT antibody positive [1.63% (4/245) vs 1.63% (4/246), P=0.726] were similar between argatroban group and the heparin group. Mechanical ventilation time was shorter in the argatroban group than that in the heparin group [13.0 (11.0, 21.0) vs 15.5 (12.0, 21.0) h, P=0.020]. Conclusion: Compared with heparin, routine management with argatroban for arteriovenous flush in patients undergoing cardiovascular surgery does not affect the HIT incidence.

Impact of Alteplase on Mortality in Critically Ill Patients with COVID-19 and Pulmonary Embolism.

COVID-19 is an independent risk factor for pulmonary embolism (PE). Little is known about alteplase therapy in this patient group. A retrospective study analyzed 74 patients with PE and acute respiratory distress syndrome (ARDS) due to COVID-19 who were hospitalized in the intensive care unit in 2021. Patients with or without confirmed right heart thrombi (RHT) were treated with unfractionated heparin or alteplase. The mortality rate in patients with RHT treated with heparin was 100% compared to 37.9% and 55.2% in those treated with alteplase without RHT and alteplase with RHT, respectively. The risk of death in the alteplase group increased with delayed thrombolysis (p = 0.009, odds ratio (OR) = 1.73 95% CI (confidence interval) 1.14-2.62), increased D-dimer concentration (p = 0.02, OR = 1.43 95% CI 1.06-1.93), and decreased PaO2/FiO2 ratio (p = 0.001, OR = 0.56 95% CI 0.41-0.78). The receiver operating characteristic method determined that a 1-day delay in thrombolytic treatment, D-dimer concentration >5.844 mg/L, and PaO2/FiO2 <144 mmHg predicted a fatal outcome. The risk of death in patients with severe COVID-19 with ARDS and PE increases with higher D-dimer levels, decreased PaO2/FiO2, and delayed thrombolytic treatment. Thrombolysis seems to be treatment of choice in severe COVID-19 with PE and RHT. It should be carried out as soon as possible after the diagnosis is established.

End-on PEGylation of heparin: Effect on anticoagulant activity and complexation with protamine.

Heparin is the most common anticoagulant used in clinical practice but shows some downsides such as short half-life (for the high molecular weight heparin) and secondary effects. On the other hand, its low molecular weight analogue cannot be neutralized with protamine, and therefore cannot be used in some treatments. To address these issues, we conjugated polyethylene glycol (PEG) to heparin reducing end (end-on) via oxime ligation and studied the interactions of the conjugate (Hep-b-PEG) with antithrombin III (AT) and protamine. Isothermal titration calorimetry showed that Hep-b-PEG maintains the affinity to AT. Dynamic light scattering demonstrated that the Hep-b-PEG formed colloidal stable nanocomplexes with protamine instead of large multi-molecular aggregates, associated with heparin side effects. The in vitro (human plasma) and in vivo experiments (Sprague Dawley rats) evidenced an extended half-life and higher anticoagulant activity of the conjugate when compared to unmodified heparin.

Safety of routine protamine in the reversal of heparin in percutaneous coronary intervention: A systematic review and meta-analysis.

OBJECTIVES: To determine the safety and efficacy of protamine in the reversal of heparin in percutaneous coronary intervention (PCI). BACKGROUND: Heparin is routinely used for anticoagulation in PCI. Protamine is not used routinely to reverse heparin's effects in PCI, partly due to the perceived risk of stent thrombosis. METHODS: Relevant studies published in English were searched for in PubMed, Embase, and Cochrane databases from inception to April 26th, 2023. Our primary outcome of interest was stent thrombosis in patients receiving PCI for all indications. Secondary outcomes included mortality, major bleeding complications, and hospitalization length. Dichotomous outcomes were analyzed using a Mantel-Haenszel random-effects model and expressed as odds ratios (OR) with their 95% confidence intervals (CI), while continuous outcomes were analyzed using an inverse variance random-effects model expressed as mean differences (MD) with their 95% CI. RESULTS: 11 studies were included in our analysis. Protamine use was not associated with stent thrombosis: OR 0.58, 95% CI: 0.33, 1.01 (p = 0.05) nor with mortality (p = 0.89). Protamine administration was associated with a decreased incidence of major bleeding complications: OR 0.48; 95% CI: 0.25, 0.95 (p = 0.03) and decreased length of hospitalization (p < 0.0001). CONCLUSIONS: In patients pre-treated with dual antiplatelet therapy (DAPT), protamine may be a safe and efficacious option to facilitate earlier sheath removal, reduce major bleeding complications, and reduce length of hospitalization without increased risk of stent thrombosis.

Novel Tissue Factor Inhibition for Thromboprophylaxis in COVID-19: Primary Results of the ASPEN-COVID-19 Trial.

BACKGROUND: Thrombo-inflammation is central to COVID-19-associated coagulopathy. TF (tissue factor), a driver of disordered coagulation and inflammation in viral infections, may be a therapeutic target in COVID-19. The safety and efficacy of the novel TF inhibitor rNAPc2 (recombinant nematode anticoagulation protein c2) in COVID-19 are unknown. METHODS: ASPEN-COVID-19 was an international, randomized, open-label, active comparator clinical trial with blinded end point adjudication. Hospitalized patients with COVID-19 and elevated D-dimer levels were randomized 1:1:2 to lower or higher dose rNAPc2 on days 1, 3, and 5 followed by heparin on day 8 or to heparin per local standard of care. In comparisons of the pooled rNAPc2 versus heparin groups, the primary safety end point was major or nonmajor clinically relevant International Society of Thrombosis and Haemostasis bleeding through day 8. The primary efficacy end point was proportional change in D-dimer concentration from baseline to day 8, or discharge if before day 8. Patients were followed for 30 days. RESULTS: Among 160 randomized patients, median age was 54 years, 43.1% were female, and 38.8% had severe baseline COVID-19. There were no significant differences between rNAPc2 and heparin in bleeding or other safety events. Overall, median change in D-dimer was -16.8% (interquartile range, -45.7 to 36.8; P=0.41) with rNAPc2 treatment and -11.2% (-36.0 to 34.4; P=0.91) with heparin (Pintergroup=0.47). In prespecified analyses, in severely ill patients, D-dimer levels tended to increase more within the heparin (median, 29.0% [-14.9 to 145.2]; P=0.02) than the rNAPc2 group (median, 25.9% [-49.1 to 136.4]; P=0.14; Pintergroup=0.96); in mildly ill patients, D-dimer levels were reduced within each group with a numerically greater reduction with rNAPc2 versus heparin (rNAPc2 median, -32.7% [-44.7 to 4.3]; P=0.007 and heparin median, -16.8% [-36.0 to 0.5]; P=0.008, Pintergroup=0.34). CONCLUSIONS: rNAPc2 treatment in hospitalized patients with COVID-19 was well tolerated without excess bleeding or serious adverse events but did not significantly reduce D-dimer more than heparin at day 8. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04655586.

[Evaluation of a diagnostic test for heparin-induced thrombocytopenia: validation of a delayed test time]. / Évaluation d'un test d'orientation diagnostique de thrombopénie induite à l'héparine : validation d'un délai différé de réalisation du test.

Heparin-induced thrombocytopenia (HIT) is a rare, iatrogenic condition, characterized by its potential severity and diagnostic difficulties. The diagnosis is based on a set of arguments allowing the calculation of a pre-test score pointing to HIT. There are rapid diagnostic tests for suspected HIT. Among these, the STic Expert® HIT has a good sensitivity to detect HIT. However, it must be performed within 2 hours after sampling. The aim of this study was to evaluate a delayed STic Expert® HIT test at 8 hours and in frozen plasma. Thirty-six patients were prospectively included for HIT testing between April 01, 2018, and July 1, 2022, at the University Rouen Hospital. For any request for HIT testing, an analysis by STic Expert® HIT was performed within 2 hours and 8 hours post-sampling. Any positive result was confirmed by a functional test, platelet aggregation with heparin, release of 14C-serotonin assay (SRA), and immunological assay by a research for anti-platelet factor 4 IgG antibodies. Twenty-three patients had a STic Expert® HIT. Sixteen presented platelet aggregations in the presence of heparin and had a positive anti-PF4 test, 17 had a positive SRA. Six patients had no HIT. For the test performed within 2 hours of collection, the Se = 100%, Sp = 68.42%, PPV = 73.91%, and NPV = 100%. The X2 = 18.21 with p < 0.001. For the test performed at 8 hours post sampling, the Se = 100%, Sp = 68.42%, PPV = 73.91% and NPV = 100%. The X2 = 18.21 with p < 0.001. In conclusion, we have demonstrated that the STic Expert® can be used to perform an HIT diagnostic test 8 hours after sampling and on thawed plasma. However, this study needs to be confirmed on a larger number of samples.

Low-dose thrombolytic therapy versus unfractionated heparin in patients with intermediate-high risk pulmonary embolism.

BACKGROUND: Patients with intermediate-high risk pulmonary embolism (PE) who have acute right ventricular dysfunction and myocardial injury without overt hemodynamic compromise may be candidates for thrombolytic therapy (TT). In this study, we aimed to compare the clinical outcomes of low-dose prolonged TT and unfractionated heparin (UFH) in intermediate-high risk PE patients. METHODS: This study enrolled 83 (female: 45 [54.2%], mean age: 70.07±10.7 years) retrospectively evaluated patients with the diagnosis of acute PE who were treated with low-dose and slow-infusion of TT or UFH. The primary outcomes of the study were de-fined as a combination of death from any cause and hemodynamic decompensation, and severe or life-threatening bleeding. Secondary endpoints were recurrent PE, pulmonary hypertension, and moderate bleeding. RESULTS: The initial management strategy of intermediate-high risk PE was TT in 41 (49.4%) patients and UFH in 42 (50.6%) cases. Low-dose prolonged TT was successful in all patients. While the frequency of hypotension decreased significantly after TT (22 vs. 0%, P<0.001), it did not decrease after UFH (2.4 vs. 7.1%, p=0.625). The proportion of hemodynamic decompensation was significantly lower in the TT group (0 vs. 11.9%, p=0.029). The rate of secondary endpoints was significantly higher in the UFH group (2.4 vs. 19%, P=0.016). Moreover, the prevalence of pulmonary hypertension was significantly higher in UFH group (0 vs. 19%, p=0.003). CONCLUSION: Prolonged TT regimen with low dose, slow infusion of tissue plasminogen activator was found to be associated with a lower risk of hemodynamic decompensation and pulmonary hypertension in patients with acute intermediate-high-risk PE compared to UFH.

Clinical decision support to reduce unnecessary diagnostic testing for heparin-induced thrombocytopenia.

Appropriate evaluation of heparin-induced thrombocytopenia (HIT) is imperative because of the potentially life-threatening complications. However, overtesting and overdiagnosis of HIT are common. Our goal was to evaluate the impact of clinical decision support (CDS) based on the HIT computerized-risk (HIT-CR) score, designed to reduce unnecessary diagnostic testing. This retrospective observational study evaluated CDS that presented a platelet count versus time graph and 4Ts score calculator to clinicians who initiated a HIT immunoassay order in patients with predicted low risk (HIT-CR score 0-2). The primary outcome was the proportion of immunoassay orders initiated but cancelled after firing of the CDS advisory. Chart reviews were conducted to assess anticoagulation usage, 4Ts scores and the proportion of patients who had HIT. In a 20-week period, 319 CDS advisories were presented to users who initiated potentially unnecessary HIT diagnostic testing. The diagnostic test order was discontinued in 80 (25%) patients. Heparin products were continued in 139 (44%) patients, and alternative anticoagulation was not given to 264 (83%). The negative predictive value of the advisory was 98.8% (95% CI: 97.2-99.5). HIT-CR score-based CDS can reduce unnecessary diagnostic testing for HIT in patients with a low pretest probability of HIT.

Inadequate Venous Thromboembolism Chemoprophylaxis Is Associated With Higher Venous Thromboembolism Rates Among Trauma Patients With Epidurals.

INTRODUCTION: Guidelines encourage higher doses of low molecular weight heparin (LMWH) for prophylaxis in trauma patients. The risks of LMWH must be considered for patients who require an epidural catheter. We compared adequate and inadequate prophylaxis to determine if venous thromboembolism (VTE) and complication rates differed among patients with epidural catheters. METHODS: Trauma patients who required an epidural catheter between 2012 and 2019 were reviewed for VTE and epidural-related complications. Adequate dosing was defined as enoxaparin 30 mg or 40 mg twice daily. Inadequate dosing was defined as unfractionated heparin subcutaneously or enoxaparin once daily. RESULTS: Over the 8-y study period, 113 trauma patients required an epidural catheter of which 64.6% were males with a mean age of 55.8 y and injury severity score of 14. Epidural catheters were associated with 11 (9.7%) patients developing an acute deep vein thrombosis (DVT) and 2 (1.8%) patients with an acute pulmonary embolism. Those patients who received adequate doses of enoxaparin were less likely to have any VTE or DVT. Complications associated with epidural catheters were not dependent on the type of pharmacological prophylaxis. CONCLUSIONS: Given the high VTE rate observed in trauma patients who required an epidural catheter, along with the low complication rate that was observed independent of the type of pharmacological prophylaxis given, the data indicate that current efforts for higher doses of LMWH appear to be safe and associated with a lower VTE rate.