[Heparin resistance and antithrombin deficiency]

Applications of rotational thromboelastometry in heparin monitoring in critical COVID-19 disease: Observations in the Maastricht Intensive Care COVID cohort

Background

Critically ill COVID-19 patients are at risk for venous thromboembolism (VTE). Therefore, they receive thromboprophylaxis and, when appropriate, therapeutic unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH). To monitor heparins in COVID-19 disease, whole-blood rotational thromboelastometry (ROTEM) may be a promising alternative to the aPTT and anti-Xa assays.

Objective

To evaluate the ROTEM INTEM/HEPTEM ratios in mechanically ventilated COVID-19 patients treated with UFH and therapeutic LMWH.

Material and methods

A subcohort of mechanically ventilated COVID-19 patients of the prospective Maastricht Intensive Care Covid (MaastrICCht) cohort was studied. Anti-Xa, aPTT, and ROTEM measurements following treatment with UFH or therapeutic dose of LMWH (nadroparin) were evaluated using uni- and multivariable linear regression analysis and receiver operating characteristics.

Results

A total of 98 patients were included, of which 82 were treated with UFH and 16 with therapeutic LMWH. ROTEM-measured INTEM/HEPTEM CT ratio was higher in patients using UFH (1.4 [1.3-1.4]) compared to patients treated with LMWH (1.0 [1.0-1.1], p < 0.001). Both the aPTT and anti-Xa were associated with the CT ratio. However, the β-regression coefficient (95%CI) was significantly higher in patients on UFH (0.31 (0.001-0.62)) compared to therapeutic LMWH (0.09 (0.05-0.13)) for comparison with the anti-Xa assay. Furthermore, ROC analysis demonstrated an area under the curve for detecting UFH of 0.936(0.849-1.00), 0.851(0.702-1.000), and 0.645(0.465-0.826) for the CT ratio, aPTT, and anti-Xa, respectively.

Conclusion

The ROTEM INTEM/HEPTEM CT ratio appears a promising tool to guide anticoagulant therapy in ICU patients with COVID-19 disease, but associations with clinical endpoints are currently lacking.

Pharmacological methods for blood stabilization in the extracorporeal circuit (review of literature)

We summarize the possible benefits and risks of using various anticoagulants during hemoperfusion. Clotting in the extracorporeal circuit can lead to a decrease in the effectiveness of therapy,  additional workload,  risk to the patient and economic losses. At the same time, relatively excessive anticoagulation against the background of existing hemostasis  disorders  can lead to severe hemorrhagic complications, which in turn  worsen the prognosis of patients. The article describes the causes of heparin resistance, the main techniques for overcoming it, and provides practical guidelines for anticoagulant therapy during hemoperfusion. It is well known that routine methods of monitoring hemostasis (such as platelet count, activated partial thromboplastin time) are unable to assess the balance of pro/anticoagulants. The authors have proposed a reasonable personalized approach to anticoagulant therapy  of extracorporeal blood purification depending  on the pathology  in patient and thromboelastography (TEG) data, and antithrombin III levels.

The role of rotational thromboelastometry during the COVID-19 pandemic: a narrative review

The coronavirus disease 2019 (COVID-19) pandemic is currently recognized as a global health crisis. This viral infection is frequently associated with hypercoagulability, with a high incidence of thromboembolic complications that can be fatal. In many situations, the standard coagulation tests (SCT) fail to detect this state of hypercoagulability in patients with COVID-19 since clotting times are either not or only mildly affected. The role of viscoelastic tests such as rotational thromboelastometry (ROTEM^®) during this pandemic is explored in this review. COVID-19-associated coagulopathy, as measured using the rotational thromboelastometry parameters, can vary from hypercoagulability due to increased fibrin polymerization and decreased fibrinolysis to bleeding from hypocoagulability. The use of a multimodal diagnostic and monitoring approach, including both rotational thromboelastometry and SCT, such as plasma fibrinogen and D-dimer concentrations, is recommended. Rotational thromboelastometry provides comprehensive information about the full coagulation status of each patient and detects individual variations. Since COVID-19-associated coagulopathy is a very dynamic process, the phenotype can change during the course of infection and in response to anticoagulation therapy. Data from published literature provide evidence that the combination of rotational thromboelastometry and SCT analysis is helpful in detecting hemostasis issues, guiding anticoagulant therapy, and improving outcomes in COVID-19 patients. However, more research is needed to develop evidence-based guidelines and protocols.

Understanding the andromeda strain - The role of cytokine release, coagulopathy and antithrombin III in SARS-CoV2 critical illness

As the current coronavirus pandemic continues and cases of COVID-19 critical illness rise, physicians and scientists across the globe are working to understand and study its pathophysiology. Part of the pathology of this illness may result from its prothrombotic potential as witnessed from derangements in coagulation and thrombotic complications reported in observational studies performed in China and Europe to findings of microthrombosis upon autopsy analysis of patients who succumbed to COVID-19. Multiple organizations, including the American Society of Hematology (ASH), recommend the routine use of prophylactic heparin to temper the thrombotic complications of this illness given its mortality benefit in severe COVID-19 infections. Reductions in circulating levels of Antithrombin III (AT), the primary mediator of heparin's action, is present in cases of coronavirus related critical illness. AT's use as a prognostic marker, an important effector of heparin resistance, and a potential therapeutic target for COVID-19 remains to be explored.

Cost-effectiveness of Argatroban Versus Heparin Anticoagulation in Adult Extracorporeal Membrane Oxygenation Patients

Purpose: The purpose of this study was to evaluate the cost effectiveness of argatroban compared to heparin during extracorporeal membrane oxygenation (ECMO) therapy. Methods: This was a retrospective study of patients who received argatroban or heparin infusions with ECMO therapy at a community hospital between January 1, 2017 and June 30, 2018. Adult patients who received heparin or argatroban for at least 48 hours while on venovenous (VV) or venoarterial (VA) ECMO were included. Patients with temporary mechanical circulatory assist devices were excluded. Each continuous course of anticoagulant exposure that met the inclusion criteria was evaluated. The primary endpoint was the total cost of anticoagulant therapy for heparin versus argatroban, including all administered study drugs, blood or factor products, and associated laboratory tests. Secondary endpoints included safety and efficacy of anticoagulation with each agent during ECMO. Documentation of bleeding events, circuit clotting, and ischemic events were noted. Partial thromboplastin time (PTT) values were evaluated for time to therapeutic range and percentage of therapeutic PTTs. Results: A total of 11 courses of argatroban and 24 courses of heparin anticoagulation were included in the study. The average cost per course of argatroban was less than the average cost per course of heparin ($7,091.98 vs $15,323.49, respectively; P value = 0.15). Furthermore, argatroban was not associated with an increased incidence of bleeding, thrombotic, or ischemic events. Conclusion: Argatroban may be more cost-effective during ECMO therapy in patients with low antithrombin III levels without increased risk of adverse events.

To be or not to be a case of heparin resistance

Heparin resistance can be defined as high doses of unfractionated heparin (UFH), greater than 35,000 IU/day, required to raise the activated partial thromboplastin time (aPTT) and activated coagulation time (ACT) to within therapeutically desired ranges or the impossibility of doing so. The most common pathology responsible is the deficiency of anti-thrombin III (ATIII) deficiency. Other clinically relevant conditions that can present with heparin resistance are congenital deficiencies; use of high doses of heparin during extracorporeal circulation, use of asparaginase therapy and disseminated intravascular coagulation (DIC). Most of these conditions effect the ATIII levels. Patients are typically identified in an acute phase, when determination of the cause of resistance is challenging. We present a case where a patient presented with suspected heparin resistance in an acute phase of sickness, where timely intervention was able to prevent a potentially fatal situation.

Abbreviations: Neuroendocrine tumors (NETs), World health Organization (WHO), Radiation therapy (RT)

Incomplete Resolution of Deep Vein Thromboses during Rivaroxaban Therapy

We present the case of a patient with a deep vein thrombosis (DVT) who failed rivaroxaban therapy. Our patient initially presented with left lower extremity edema, erythema, and pain. He was subsequently started on rivaroxaban therapy for a combined treatment period of 12 months, during and after which he persisted to have evidence of a DVT. The patient's prescribed drug regimen was changed from rivaroxaban to warfarin, which demonstrated a rapid resolution of the DVTs as determined by ultrasound assessment of our patient's lower extremity veins. Rivaroxaban, a factor Xa inhibitor, is a well-known oral anticoagulant that is used for a variety of indications and has become a mainstay in the treatment of deep vein thrombosis. With the introduction and emergence of this medication in the clinic, postmarketing reports of efficacy or lack thereof are important to review. In conclusion, we anticipate that it is likely that there are other patients with DVTs who may not respond to rivaroxaban and for whom alternative anticoagulation therapies should be explored.

The evaluations of frequency distribution heparin resistance during coronary artery bypass graft

BACKGROUND

Heparin is one of the most important medication that is used in coronary artery bypass graft (CABG) operations, but some patients demonstrate heparin resistance (HR) during CABG. Heparin resistance was defined as at least one activated clothing time <400 seconds after heparinization and/or the need for purified antithrombin III (AT-III) administration. The goal of this study was the investigation of HR prevalence in our country and relation between HR and post-operative CABG complications.

MATERIALS AND METHODS

One hundred patients that candidate for CABG were selected and surveyed for HR and complications. The data entered to computer and analyzed by SPSS soft ware. The Chi-square and student t-tests were used for data analysis.

RESULTS

The prevalence of heparin resistance in our study was 3%. There was no relation among bleeding, cardiac arrest and HR. Bleeding happened in 13 patients of which 1 person was in HR group (33.3%) and 12 in non HR group (12.4%) (P = 0.34). Cardiac arrest happened in 8 patients, 1 person was in HR group (33.3%) and 7 in non HR group (7.2%) (P = 0.22). According our data there were no relation among HR and gender and ventilator dependency time.

CONCLUSIONS

HR is a nearly prevalent complication among patients that undergone CABG that may led to some complications such as bleeding and cardiac arrest. In our study, we did not find significant relation among them, but in frequency these complications were higher in HR group.