Argatroban and Bivalirudin for Perioperative Anticoagulation in Cardiac Surgery

An ISHLT consensus statement on strategies to prevent and manage hemocompatibility related adverse events in patients with a durable, continuous-flow ventricular assist device

Life expectancy of patients with a durable, continuous-flow left ventricular assist device (CF-LVAD) continues to increase. Despite significant improvements in the delivery of care for patients with these devices, hemocompatability-related adverse events (HRAEs) are still a concern and contribute to significant morbility and mortality when they occur. As such, dissemination of current best evidence and practices is of critical importance. This ISHLT Consensus Statement is a summative assessment of the current literature on prevention and management of HRAEs through optimal management of oral anticoagulant and antiplatelet medications, parenteral anticoagulant medications, management of patients at high risk for HRAEs and those experiencing thrombotic or bleeding events, and device management outside of antithrombotic medications. This document is intended to assist clinicians caring for patients with a CF-LVAD provide the best care possible with respect to prevention and management of these events.

Plasma exchange and intravenous immunoglobulin for the peri-operative management of type 2 heparin-induced thrombocytopaenia in a patient requiring urgent surgery for critical limb ischaemia

We report the case of a 61-year-old female who developed heparin-induced thrombocytopaenia following treatment of a submassive pulmonary embolism, and who then required an above knee amputation for critical limb ischaemia. Heparin-induced thrombocytopaenia is a rare, immune-mediated complication associated with an in-hospital mortality rate of 10%. It is more common in surgical patients, with patients undergoing orthopaedic surgery more likely to develop it than patients undergoing cardiac surgery, but heparin-dependent immunoglobulin G antibodies are more likely to be formed in the latter. Peri-operative management remains a challenge. Ideally, it is preferable to wait for the platelet count to improve; but in certain cases, surgery cannot be delayed. Heparin-induced thrombocytopaenia is usually managed with direct thrombin inhibitors, such as argatroban and bivalirudin. Newer therapeutic modalities, such as plasmapheresis and intravenous immunoglobulin, as used in this case, can rapidly remove antibodies, but the certainty of evidence is low. Our case adds to the literature regarding the use of these modalities and highlights the multidisciplinary team approach required to manage such complex cases.

Stroke prevention strategies for cardiac surgery: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Stroke is a much-feared complication of cardiac surgery, but existing literature on preventive strategies is fragmented. Hence, a systematic review and meta-analysis of stroke prevention strategies for cardiac surgery was conducted.

METHODS

An electronic literature search was conducted to retrieve randomized controlled trials (RCTs) investigating perioperative interventions for cardiac surgery, with stroke as an outcome. Random-effects meta-analyses were conducted to generate risk ratios (RRs), 95% confidence intervals (95% CI), and forest plots. Descriptive analysis and synthesis of literature was conducted for interventions not amenable to meta-analysis, focusing on risks of stroke, myocardial infarction and study-defined major adverse cardiovascular events (MACE).

RESULTS

Fifty-six RCTs (61 894 patients) were retrieved. Many included trials were underpowered to detect differences in stroke risk. Among pharmacological therapies, only preoperative amiodarone was shown to reduce stroke risk in one trial. Concomitant left atrial appendage closure (LAAC) significantly reduced stroke risk (RR = 0.55, 95% CI = 0.36-0.84, P = 0.006) in patients with preoperative atrial fibrillation, and there was no difference in on-pump versus off-pump coronary artery bypass grafting (CABG) (RR = 0.94, 95% CI = 0.64-1.37, P = 0.735). Much controversy exists in literature on the timing of carotid endarterectomy relative to CABG in patients with severe carotid stenosis. The use of preoperative remote ischemic preconditioning was not found to reduce rates of stroke or MACE.

CONCLUSION

This review presents a comprehensive synthesis of existing interventions for stroke prevention in cardiac surgery, and identifies gaps in research which may benefit from future, large-scale RCTs. LAAC should be considered to reduce stroke incidence in patients with preoperative atrial fibrillation.

Bivalirudin anticoagulation for cardiopulmonary bypass during cardiac surgery

INTRODUCTION

Heparin is the primary anticoagulant for cardiopulmonary bypass (CPB) support during cardiac surgery. While widely used, ∼2% of cardiac surgery patients develop heparin-induced thrombocytopenia (HIT) and 4-26% develop heparin resistance. Bivalirudin is an alternative anticoagulant mainly used for percutaneous coronary interventions. Given the challenges associated with heparin anticoagulation, we conducted a review to explore the use of bivalirudin for CPB surgery.

METHODS

PubMed and Embase scoping review included 2 randomized controlled trials, a retrospective comparison study, 3 pilot studies, and 30 case reports. To provide a contemporary series, we searched for articles published from 2010 to 2023. Our review included studies from both adult and pediatric populations.

RESULTS

While data is limited, bivalirudin seems to supply similar effectiveness and safety as heparin for CPB anticoagulation. Across the three comparative studies, the heparin cohorts had a 0-9% mortality rate and 0-27% rate of major bleeding/reoperation compared to a 0-3% mortality and 0-6% major bleeding/reoperation rate for the bivalirudin cohorts. Bivalirudin was successfully used as an anticoagulant in a wide range of CPB surgeries (e.g., heart transplants, ventricular assisted device placements, and valve repairs). Successful patient outcomes were reported with bivalirudin infusion of ∼2 mg/kg/hour, activated clotting time monitoring (target >400 s or 2.5× baseline), use of cardiotomy suctions, minimization of stagnant blood, and post-bypass modified ultrafiltration.

CONCLUSION

Bivalirudin is a safe and effective anticoagulant for CPB, especially for patients with HIT or heparin resistance. Further comparative research is called for to optimize bivalirudin utilization for CPB during cardiac surgery.

Current knowledge gaps in extracorporeal respiratory support

Extracorporeal life support (ECLS) for acute respiratory failure encompasses veno-venous extracorporeal membrane oxygenation (V-V ECMO) and extracorporeal carbon dioxide removal (ECCO2R). V-V ECMO is primarily used to treat severe acute respiratory distress syndrome (ARDS), characterized by life-threatening hypoxemia or ventilatory insufficiency with conventional protective settings. It employs an artificial lung with high blood flows, and allows improvement in gas exchange, correction of hypoxemia, and reduction of the workload on the native lung. On the other hand, ECCO2R focuses on carbon dioxide removal and ventilatory load reduction ("ultra-protective ventilation") in moderate ARDS, or in avoiding pump failure in acute exacerbated chronic obstructive pulmonary disease. Clinical indications for V-V ECLS are tailored to individual patients, as there are no absolute contraindications. However, determining the ideal timing for initiating extracorporeal respiratory support remains uncertain. Current ECLS equipment faces issues like size and durability. Innovations include intravascular lung assist devices (ILADs) and pumpless devices, though they come with their own challenges. Efficient gas exchange relies on modern oxygenators using hollow fiber designs, but research is exploring microfluidic technology to improve oxygenator size, thrombogenicity, and blood flow capacity. Coagulation management during V-V ECLS is crucial due to common bleeding and thrombosis complications; indeed, anticoagulation strategies and monitoring systems require improvement, while surface coatings and new materials show promise. Moreover, pharmacokinetics during ECLS significantly impact antibiotic therapy, necessitating therapeutic drug monitoring for precise dosing. Managing native lung ventilation during V-V ECMO remains complex, requiring a careful balance between benefits and potential risks for spontaneously breathing patients. Moreover, weaning from V-V ECMO is recognized as an area of relevant uncertainty, requiring further research. In the last decade, the concept of Extracorporeal Organ Support (ECOS) for patients with multiple organ dysfunction has emerged, combining ECLS with other organ support therapies to provide a more holistic approach for critically ill patients. In this review, we aim at providing an in-depth overview of V-V ECMO and ECCO2R, addressing various aspects of their use, challenges, and potential future directions in research and development.

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.

A Multichannel Portable Platform With Embedded Thermal Management for Miniaturized Dielectric Blood Coagulometry

This article presents a standalone, multichannel, miniaturized impedance analyzer (MIA) system for dielectric blood coagulometry measurements with a microfluidic sensor termed ClotChip. The system incorporates a front-end interface board for 4-channel impedance measurements at an excitation frequency of 1 MHz, an integrated resistive heater formed by a pair of printed-circuit board (PCB) traces to keep the blood sample near a physiologic temperature of 37 °C, a software-defined instrument module for signal generation and data acquisition, and a Raspberry Pi-based embedded computer with 7-inch touchscreen display for signal processing and user interface. When measuring fixed test impedances across all four channels, the MIA system exhibits an excellent agreement with a benchtop impedance analyzer, with rms errors of ≤0.30% over a capacitance range of 47-330 pF and ≤0.35% over a conductance range of 2.13-10 mS. Using in vitro-modified human whole blood samples, the two ClotChip output parameters, namely, the time to reach a permittivity peak (Tpeak) and maximum change in permittivity after the peak (Δϵr,max) are assessed by the MIA system and benchmarked against the corresponding parameters of a rotational thromboelastometry (ROTEM) assay. Tpeak exhibits a very strong positive correlation (r = 0.98, p < 10-6, n = 20) with the ROTEM clotting time (CT) parameter, while Δϵr,max exhibits a very strong positive correlation (r = 0.92, p < 10-6, n = 20) with the ROTEM maximum clot firmness (MCF) parameter. This work shows the potential of the MIA system as a standalone, multichannel, portable platform for comprehensive assessment of hemostasis at the point-of-care/point-of-injury (POC/POI).

Heparin-resistance in AL amyloidosis: a case report

BACKGROUND

Non-AT-III mediated heparin-resistance during CPB occurs by complex-forming with heparin-binding proteins. Currently, there are no specific recommendations for non-AT-III mediated heparin-resistance.

CASE PRESENTATION

We present a fatal case of a 70-yr-old male-patient undergoing cardiac-surgery in which refractory heparin-resistance was observed. The massive AL amyloidosis found at autopsy is thought to be responsible and illustrates that awareness and knowledge of the etiology and perioperative strategies of non-AT-III mediated heparin-resistance is important.

CONCLUSION

For anticoagulation during cardiopulmonary bypass surgery in case of a non-AT-III medicated heparin resistance, we refer to the decision tree added to this manuscript and if necessary to consider direct thrombin inhibitors, such as bivalirudin or argatroban, as it bypasses the complexing pathway.

Anticoagulation in adult patients supported with extracorporeal membrane oxygenation: guidance from the Scientific and Standardization Committees on Perioperative and Critical Care Haemostasis and Thrombosis of the International Society on Thrombosis and Haemostasis

Anticoagulation of patients supported by extracorporeal membrane oxygenation is challenging because of a high risk of both bleeding and thrombotic complications, and often empirical. Practice in anticoagulation management is therefore highly variable. The scope of this guidance document is to provide clinicians with practical advice on the choice of an anticoagulant agent, dosing, and the optimal anticoagulant monitoring strategy during extracorporeal membrane oxygenation support in adult patients.

How to Solve the Conundrum of Heparin-Induced Thrombocytopenia during Cardiopulmonary Bypass

Heparin-induced thrombocytopenia (HIT) is a major issue in cardiac surgery requiring cardiopulmonary bypass (CPB). HIT represents a severe adverse drug reaction after heparin administration. It consists of immune-mediated thrombocytopenia paradoxically leading to thrombotic events. Detection of antibodies against platelets factor 4/heparin (anti-PF4/H) and aggregation of platelets in the presence of heparin in functional in vitro tests confirm the diagnosis. Patients suffering from HIT and requiring cardiac surgery are at high risk of lethal complications and present specific challenges. Four distinct phases are described in the usual HIT timeline, and the anticoagulation strategy chosen for CPB depends on the phase in which the patient is categorized. In this sense, we developed an institutional protocol covering each phase. It consisted of the use of a non-heparin anticoagulant such as bivalirudin, or the association of unfractionated heparin (UFH) with a potent antiplatelet drug such as tirofiban or cangrelor. Temporary reduction of anti-PF4 with intravenous immunoglobulins (IvIg) has recently been described as a complementary strategy. In this article, we briefly described the pathophysiology of HIT and focused on the various strategies that can be applied to safely manage CPB in these patients.

Heparin Resistance During Cardiopulmonary Bypass in Adult Cardiac Surgery

The use of heparin for anticoagulation has changed the face of cardiac surgery by allowing a bloodless and motionless surgical field throughout the introduction of cardiopulmonary bypass (CPB). However, heparin is a drug with complex pharmacologic properties that can cause significant interpatient differences in terms of responsiveness. Heparin resistance during CPB is a weighty issue due to the catastrophic consequences stemming from inadequate anticoagulation, and the treatment of it necessitates a rationalized stepwise approach due to the multifactorial contributions toward this entity. The widespread use of activated clotting time (ACT) as a measurement of anticoagulation during CPB is examined, as it may be a false indicator of heparin resistance. Heparin resistance also has been repeatedly reported in patients infected with COVID-19, which deserves further exploration in this pandemic era. This review aims to examine the variability in heparin potency, underlying mechanisms, and limitations of using ACT for monitoring, as well as provide a framework towards the current management of heparin resistance.

Successful Application of Argatroban During VV-ECMO in a Pregnant Patient Complicated With ARDS due to Severe Tuberculosis: A Case Report and Literature Review

Severe tuberculosis during pregnancy may progress to acute respiratory distress syndrome (ARDS), and venovenous (VV) extracorporeal membrane oxygenation (ECMO) should be considered if conventional lung-protective mechanical ventilation fails. However, thrombocytopenia often occurs with ECMO, and there are limited reports of alternative anticoagulant therapies for pregnant patients with thrombocytopenia during ECMO. This report describes the first case of a pregnant patient who received argatroban during ECMO and recovered. Furthermore, we summarized the existing literature on VV-ECMO and argatroban in pregnant patients. A 31-year-old woman at 17 weeks of gestation was transferred to our hospital with ARDS secondary to severe tuberculosis. We initiated VV-ECMO after implementing a protective ventilation strategy and other conventional therapies. Initially, we selected unfractionated heparin anticoagulant therapy. However, on ECMO day 3, the patient’s platelet count and antithrombin III (AT-III) level declined to 27 × 103 cells/μL and 26.9%, respectively. Thus, we started the patient on a 0.06 μg/kg/min argatroban infusion. The argatroban infusion maintenance dose ranged between 0.9 and 1.2 μg/kg/min. The actual activated partial thromboplastin clotting time and activated clotting time ranged from 43 to 58 s and 220–260 s, respectively, without clinically significant bleeding and thrombosis. On day 27, the patient was weaned off VV-ECMO and eventually discharged. VV-ECMO may benefit pregnant women with refractory ARDS, and argatroban may be an alternative anticoagulant for pregnant patients with thrombocytopenia and AT-III deficiency during ECMO.

The Changing Landscape of Anticoagulation in Pediatric Extracorporeal Membrane Oxygenation: Use of the Direct Thrombin Inhibitors

Bleeding and thrombosis frequently occur in pediatric patients with extracorporeal membrane oxygenation (ECMO) therapy. Until now, most patients are anticoagulated with unfractionated heparin (UFH). However, heparin has many disadvantages, such as binding to other plasma proteins and endothelial cells in addition to antithrombin, causing an unpredictable response, challenging monitoring, development of heparin resistance, and risk of heparin-induced thrombocytopenia (HIT). Direct thrombin inhibitors (DTIs), such as bivalirudin and argatroban, might be a good alternative. This review will discuss the use of both UFH and DTIs in pediatric patients with ECMO therapy.

Heparin desensitisation prior to cardiopulmonary bypass in a patient with alpha-gal allergy

This case report describes the implementation of a heparin desensitisation strategy for a patient with confirmed galactose-alpha-1,3-galactose (alpha-gal) allergy, prior to cardiac surgery. We describe the pre-, intra- and postoperative management. We believe this report can enhance the limited data currently in existence on alternative strategies for heparin utilisation in cardiopulmonary bypass in a previously intolerant patient population.

[The role of thrombin in the pathogenesis of atherosclerosis and its complications]

Thrombin is a key regulator of the homeostasis system. Also, it actively participates in progression of various systemic diseases, including atherosclerosis. There is a large amount of experimental and clinical data on the involvement of thrombin in the pathogenesis of ischemic heart disease (IHD). Thus, studying thrombin activity regulation is promising. Also, the question whether it is possible to use biomarkers of thrombin activity as predictors of cardiovascular complications in IHD patients is relevant. The present review focuses on major mechanisms of thrombin functioning, its role in development and progression of atherosclerosis, and available tests for evaluation of thrombin functional activity. Major clinical studies are discussed that evaluated the efficacy of thrombin inhibitors and protease-activated receptor antagonists.

Heparin-induced Thrombocytopenia: Perioperative Diagnosis and Management

Heparin-induced thrombocytopenia is a severe prothrombotic disease. Timely diagnosis and treatment are essential. Application of diagnostic algorithms based on validated clinical scoring tools and rapid, specific laboratory assays may improve outcomes.

Bivalirudin for the prevention of hepatic artery thrombosis in pediatric liver transplantation

BACKGROUND

Early hepatic artery thrombosis (HAT) after liver transplantation is a serious complication that frequently results in graft loss and the need for retransplantation. Although studies have reported on various operative and endovascular treatment approaches, pharmacologic strategies for the prevention or management of HAT are not well defined. Patients with blood clotting disorders, those with a contraindication to heparin, and those who have previously developed HAT represent unique challenges in management.

METHODS

We present the case of a 9-month-old male with a hypercoagulable state who developed early HAT after two liver transplants, despite the use of postoperative therapeutic heparin infusion.

RESULTS AND CONCLUSION

The patient successfully underwent a third liver transplant using intraoperative and postoperative bivalirudin infusion, a direct thrombin inhibitor. Rotational thromboelastometry (ROTEM) was used to guide anticoagulation and blood product administration in the perioperative period. At 1.5 years post-transplant, the patient has good graft function with patent hepatic vasculature. This case demonstrates the innovative use of bivalirudin anticoagulant therapy and viscoelastic methodologies to improve outcomes in hypercoagulable liver transplant recipients.

Anticoagulation Monitoring for Perioperative Physicians

From preoperative medications to intraoperative needs to postoperative thromboprophylaxis, anticoagulants are encountered throughout the perioperative period. This review focuses on coagulation testing clinicians utilize to monitor the effects of these medications.

Affinity ultrafiltration and UPLC-HR-Orbitrap-MS based screening of thrombin-targeted small molecules with anticoagulation activity from Poecilobdella manillensis

This study aims to screen potential anticoagulant components from leeches, a representative animal-sourced traditional Chinese medicine using thrombin (THR)-targeted ultrafiltration combined with ultrahigh performance liquid chromatography and high-resolution Orbitrap mass spectrometry (UPLC-HR-Orbitrap-MS). As a result, five small molecules in leech extract were discovered to interact with THR for the first time. Among them, two new compounds were isolated and their structures were identified by IR, HR-MS and NMR data. Furthermore, their THR inhibitory activity was confirmed with IC₅₀ values of 4.74 and 8.31 μM, respectively. In addition, molecular docking analysis showed that the active (catalytic) site of THR might be the possible binding site of the two hits. Finally, reverse screening analysis indicated that LTA4-H, ACE and ALOX5AP were potential anticoagulant targets of the two new compounds. This study will broaden our understanding of the medicinal substance basis in leeches and further contribute to the discovery and development of clinical anticoagulant drugs from leeches.

COVID-19 Associated Hypercoagulability: Manifestations, Mechanisms, and Management

ABSTRACT

Patients with severe coronavirus disease-2019 (COVID-19) frequently have hypercoagulability caused by the immune response to the severe acute respiratory syndrome coronavirus-2 infection. The pathophysiology of COVID-19 associated hypercoagulability is not fully understood, but characteristic changes include: increased fibrinogen concentration, increased Factor VIII activity, increased circulating von Willebrand factor, and exhausted fibrinolysis. Anticoagulant therapy improves outcomes in mechanically ventilated patients with COVID-19 and viscoelastic coagulation testing offers an opportunity to tailor anticoagulant therapy based on an individual patient's coagulation status. In this narrative review, we summarize clinical manifestations of COVID-19, mechanisms, monitoring considerations, and anticoagulant therapy. We also review unique considerations for COVID-19 patients who are on extracorporeal membrane oxygenation.

Argatroban Anticoagulation for Adult Extracorporeal Membrane Oxygenation: A Systematic Review

BACKGROUND

Heparin is the widely used anti-coagulation strategy for patients on extracorporeal membrane oxygenation (ECMO). Nevertheless, heparin-induced thrombocytopenia (HIT) and acquired anti-thrombin (AT) deficiency preclude the use of heparin requiring utilization of an alternative anticoagulant agent. Direct thrombin inhibitors are being proposed as potential alternatives with argatroban as one of the main agents. We aimed to review the evidence with regard to safety and efficacy of argatroban as a potential definitive alternative to heparin in the adult patient population undergoing ECMO support.

METHODS

A web-based systematic literature search was performed in Medline (PubMed) and Embase from inception until June 18, 2020.

RESULTS

The search identified 13 publications relevant to the target (4 cohort studies and 9 case series). Case reports and case series with less than 3 cases were not included in the qualitative synthesis. The aggregate number of argatroban treated patients on ECMO was n = 307. In the majority of studies argatroban was used as a continuous infusion without loading dose. Starting doses on ECMO varied between 0.05 and 2 μg/kg/min and were titrated to achieve the chosen therapeutic target range. The activated partial thormboplastin time (aPTT) was the anticoagulation parameter used for monitoring purposes in most studies, whereas some utilized the activated clotting time (ACT). Optimal therapeutic targets varied between 43-70 and 60-100 seconds for aPTT and between 150-210 and 180-230 seconds for ACT. Bleeding and thromboembolic complication rates were comparable to patients treated with unfractionated heparin (UFH).

CONCLUSIONS

Argatroban infusion rates and anticoagulation target ranges showed substantial variations. The rational for divergent dosing and monitoring approaches are discussed in this paper. Argatroban appears to be a potential alternative to UFH in patients requiring ECMO. To definitively establish its safety, efficacy and ideal dosing strategy, larger prospective studies on well-defined patient populations are warranted.

GTH 2021 State of the Art-Cardiac Surgery: The Perioperative Management of Heparin-Induced Thrombocytopenia in Cardiac Surgery

Heparin-induced thrombocytopenia (HIT) is a severe, immune-mediated, adverse drug reaction that paradoxically induces a prothrombotic state. Particularly in the setting of cardiac surgery, where full anticoagulation is required during cardiopulmonary bypass, the management of HIT can be highly challenging, and requires a multidisciplinary approach. In this short review, the different perioperative strategies to run cardiopulmonary bypass will be summarized.

Successful HeartMate 3 LVAD implantation in a patient with active heparin-induced thrombocytopaenia with thrombosis using pre-implantation plasmapheresis and intraoperative continuous prostacyclin

Heparin-induced thrombocytopaenia describes a prothrombotic state with significant rates of thrombus formation. We present a rare case of successful implantation of a HeartMate 3 left ventricular assist device in a patient with active heparin-induced thrombocytopaenia with thrombosis using preoperative plasmapheresis followed by intraoperative prostacyclin administration.

Evaluation of direct thrombin inhibitors during a critical heparin shortage

A recent heparin shortage related to an outbreak of African Swine Flu in China led to substantial increase in the use of direct thrombin inhibitors (DTI) as an alternative. We evaluated the safety and efficacy of DTIs by assessing the anticoagulation assays within the initial 48 h of therapy comparing before and during shortage. A retrospective evaluation of bivalirudin and argatroban was conducted at a single center before (May 24, 2018 through August 25, 2019) and during heparin shortage (August 26, 2019 through February 20, 2020). The primary outcome was time to first therapeutic activated partial thromboplastin time (aPTT). Secondary outcomes included the percentage of time in therapeutic aPTT range, in-hospital mortality, incidence of recurrent thrombosis, and hemorrhagic events. Of the 204 patients included in the study, 95 patients [bivalirudin (n = 35), argatroban (n = 60)] were included in the pre-shortage cohort and 109 patients [bivalirudin (n = 68), argatroban (n = 41)] were during shortage. No significant difference was observed in the time to first therapeutic aPTT pre- and during shortage (8.9 h ± 10.8 vs 8.8 h ± 10.2, P = 0.62). Compared to pre-shortage cohort, a greater percentage of time was spent in therapeutic aPTT range within the initial 48 h (32% (0-50) vs. 41.6% (0-63), P = 0.04) during shortage without statistically significant differences in the rates of in-hospital mortality, thrombosis, or bleeding. While the optimal DTI protocol is still be determined, the protocols presented in this study allowed for wide-spread utilization of DTIs during a critical heparin shortage without compromising patient safety and effectiveness, likely reflective of the enhancement of DTI protocols, clinician education, and multidisciplinary collaboration and guidance from pharmacy and hematology.

How would we treat our own heparin-induced thrombocytopenia during cardiac surgery?

The aim of this article is to provide a comprehensive review of the current state of knowledge on heparin-induced thrombocytopenia (HIT) in cardiac surgery. The management of HIT patients undergoing cardiac surgery with cardiopulmonary bypass is complex and requires an interdisciplinary and patient-tailored approach because available evidence is limited and current anticoagulation strategies have potential risks. An index case is used to discuss both the established and new perioperative therapeutic options in HIT patients undergoing urgent cardiac surgery with cardiopulmonary bypass.

ISTH DIC subcommittee communication on anticoagulation in COVID-19

Hypercoagulability is an increasingly recognized complication of SARS-CoV-2 infection. As such, anticoagulation has become part and parcel of comprehensive COVID-19 management. However, several uncertainties exist in this area, including the appropriate type and dose of heparin. In addition, special patient populations, including those with high body mass index and renal impairment, require special consideration. Although the current evidence is still insufficient, we provide a pragmatic approach to anticoagulation in COVID-19, but stress the need for further trials in this area.

Heparin Induced Thrombocytopenia for the Perioperative and Critical Care Clinician

Purpose of Review

This review will illustrate the importance of heparin-induced thrombocytopenia in the intraoperative and critical care settings.

Recent Findings

Heparin-induced thrombocytopenia (HIT) occurs more frequently in surgical patients compared with medical patients due to the inflammatory release of platelet factor 4 and perioperative heparin exposure. Recognition of this disease requires a high index of suspicion. Diagnostic tools and therapeutic strategies have been expanded and refined in recent years.

Summary

HIT is a condition where antibodies against the heparin/platelet factor 4 complex interact with platelet receptors to promote platelet activation, aggregation, and thrombus formation. Our review will focus on intraoperative and postoperative considerations related to HIT to help the clinician better manage this rare but often devastating hypercoagulable disease process.

Efficiency and safety evaluation of prophylaxes for venous thrombosis after gynecological surgery

BACKGROUND

In this study, we investigate the incidence of venous thrombosis (VT), and evaluate the effectiveness and safety of 3 major thromboprophylaxes and the potential risk factors for VT in women undergoing surgery for a gynecological malignancy.

METHODS

We performed a randomized controlled trial of 307 patients undergoing laparoscopic surgery for gynecological malignancies at a single institution from January 2016 to October 2017. Patients were divided into 3 groups: one receiving a half dose of low-molecular-weight heparin sodium injection (FLUXUM, Alfa Wassermann, Italy) delivered by injection, one receiving a full dose of FLUXUM, and a third group receiving an Argatroban injection.

RESULTS

None of the patients in our study developed a pulmonary embolism, bleeding, or infectious complications. There were no statistical differences in the rate of deep venous thrombosis (DVT) (0%, 0%, and 2.38%) and the superficial venous thromboembolism (SVT) (15.66%, 8.97%, and 18.6%) among the 3 groups. None of the patients developed symptomatic VT. The effect of treatment on alanine aminotransferase and aspartate aminotransferase differed between the groups, with a minimal effect in the Argatroban group, and all 3 methods resulted in minimal impairment of renal function. Decreased hemoglobin, elevated levels of D-dimer, and prothrombin time were closely related to thrombogenesis.

CONCLUSION

In conclusion, the incidence of postoperative thrombosis in gynecological malignancy among these Chinese people is not as low as we had originally presumed. Argatroban is not more effective than Parnaparin as a direct thrombin inhibitor, but it has less influence on liver function, which is beneficial for patients undergoing chemotherapy. Hemoglobin, D-dimer, and prothrombin time may be used to predict or detect thrombogenesis.

Hematologic concerns in extracorporeal membrane oxygenation

This ISTH "State of the Art" review aims to critically evaluate the hematologic considerations and complications in extracorporeal membrane oxygenation (ECMO). ECMO is experiencing a rapid increase in clinical use, but many questions remain unanswered. The existing literature does not address or explicitly state many pertinent details that may influence hematologic complications and, ultimately, patient outcomes. This review aims to broadly introduce modern ECMO practices, circuit designs, circuit materials, hematologic complications, transfusion-related considerations, age- and size-related differences, and considerations for choosing outcome measures. Relevant studies from the 2019 ISTH Congress in Melbourne, which further advanced our understanding of these processes, will also be highlighted.

Cardiac Surgery Successfully Managed With Cangrelor in a Patient With Persistent Anti-PF4/Heparin Antibodies 8 Years After Heparin-Induced Thrombocytopenia

A 66-YEAR-OLD female requiring cardiac surgery had persisting anti-platelet factor 4 (PF4)/heparin antibodies (HIT-abs) 8 years after heparin-induced thrombocytopenia (HIT). In 2010, she developed thrombotic thrombocytopenic purpura (TTP) (ADAMTS-13 <5%, inhibitor at 1.0 BU/mL), which was treated successfully with corticotherapy, plasmapheresis, and intravenous heparin. While taking heparin, she developed HIT, as evidenced by a positive functional test. Her platelet count fully resolved without thrombotic complications with danaparoid treatment. In 2018, the preoperative titer of HIT-abs was still 0.38 U/mL by chemoluminescent immunoassay (CLIA), and positive by particle-gel agglutination immunoassay (PaGIA) with a titer of 2 and was strongly positive on an enzyme-linked immunosorbent assay (ELISA). The authors of the case report chose to use cangrelor combined with heparin during cardiopulmonary bypass (CPB). Cangrelor was used without increased postoperative bleeding or thrombotic complications. Postoperatively she exhibited a huge rise in HIT-abs (14.22 U/mL on postoperative day 11) with a positive functional assay. There was no recurrence of HIT, however. This case illustrates the importance of excluding the presence of persisting HIT-abs before CPB and ensuring close medical follow-up after even a single exposure to heparin.

Traditional and non-traditional anticoagulation management during extracorporeal membrane oxygenation

Unfractionated heparin (UFH) is the anticoagulant of choice during extracorporeal membrane oxygenation (ECMO) support. Despite its favorable pharmacologic properties, management of heparin anticoagulation during ECMO remains a major challenge. To date, little is known about the optimal monitoring strategy or the heparin dose offering the best safety/efficacy profile. Therefore, it remains unclear if the heparin dose should be adapted to target a specific "clotting time" [e.g., activated clotting time (ACT) or activated partial thromboplastin time (aPTT)] or a heparin concentration, measured by coagulation factor anti-Xa assay. In addition, no study has compared the relevance of modern viscoelastic coagulation tests over the single value of a clotting time or heparin concentration value. Although guidelines for anticoagulation during ECMO support have been published, the absence of evidence limits the quality of the recommendations provided, which explains the major intra- and inter-institutional variability observed. Large prospective multicenter trials are urgently needed to investigate the optimal anticoagulation management strategy during ECMO support.

Antithrombotic therapy management of adult and pediatric cardiac surgery patients

Despite the development of catheter-based interventions for ischemic and valvular heart disease, hundreds of thousands of people undergo open heart surgery annually for coronary artery bypass graft (CABG), valve replacement or cardiac assist device implantation. Cardiac surgery patients are unique because therapeutic anticoagulation is required during cardiopulmonary bypass. Developmental hemostasis and altered drug metabolism affect management in children. This narrative review summarizes the current evidence-based and consensus guidelines regarding perioperative, intraoperative and postoperative antithrombotic therapy in patients undergoing cardiac surgery. Anticoagulation preoperatively is required in the setting of cardiac arrhythmias, prior valve replacement or history of venous thromboembolism. In patients with ischemic heart disease, aspirin is continued in the perioperative period, whereas oral P2Y12 antagonists are withheld for 5-7 days to reduce the risk of perioperative bleeding. Intraoperative management of cardiopulmonary bypass in adults and children includes anticoagulation with unfractionated heparin. Variability in dose-response to heparin and influence of other medical conditions on dosing and reversal of heparin make intraoperative anticoagulation challenging. Vitamin K antagonist therapy is the standard anticoagulant after mechanical heart valve or left ventricular assist device (LVAD) implantation. Longer duration of dual antiplatelet therapy is recommended after CABG if patients undergo surgery because of acute coronary syndrome. Antiplatelet therapy after LVAD implantation includes aspirin, dipyridamole and/or clopidogrel in children and aspirin in adults. A coordinated approach between hematology, cardiology, anesthesiology, critical care and cardiothoracic surgery can assist to balance the risk of thrombosis and bleeding in patients undergoing cardiac surgery.