Plasma exchange to remove heparin-induced thrombocytopenia antibodies and the use of heparin during cardiopulmonary bypass in critically ill cardiac patients

Adverse Events in Total Artificial Heart for End-Stage Heart Failure: Insight From the Food and Drug Administration Manufacturer and User Facility Device Experience (MAUDE)

Background and Objectives

Real-world clinical data, outside of clinical trials and expert centers, on adverse events related to the use of SyncCardia total artificial heart (TAH) remain limited. We aim to analyze adverse events related to the use of SynCardia TAH reported to the Food and Drug Administration (FDA)'s Manufacturers and User Defined Experience (MAUDE) database.

Methods

We reviewed the FDA's MAUDE database for any adverse events involving the use of SynCardia TAH from 1/01/2012 to 9/30/2020. All the events were independently reviewed by three physicians.

Results

A total of 1,512 adverse events were identified in 453 "injury and death" reports in the MAUDE database. The most common adverse events reported were infection (20.2%) and device malfunction (20.1%). These were followed by bleeding events (16.5%), respiratory failure (10.1%), cerebrovascular accident (CVA)/other neurological dysfunction (8.7%), renal dysfunction (7.5%), hepatic dysfunction (2.2%), thromboembolic events (1.8%), pericardial effusion (1.8%), and hemolysis (1%). Death was reported in 49.4% of all the reported cases (n=224/453). The most common cause of death was multiorgan failure (n=73, 32.6%), followed by CVA/other non-specific neurological dysfunction (n=44, 19.7%), sepsis (n=24, 10.7%), withdrawal of support (n=20, 8.9%), device malfunction (n=11, 4.9%), bleeding (n=7, 3.1%), respiratory failure (n=7, 3.1%), gastrointestinal disorder (n=6, 2.7%), and cardiomyopathy (n=3, 1.3%).

Conclusions

Infection was the most common adverse event following the implantation of TAH. Most of the deaths reported were due to multiorgan failure. Early recognition and management of any possible adverse events after the TAH implantation are essential to improve the procedural outcome and patient survival.

External Trigger Free Charge Switchable Cationic Ligands in the Design of Safe and Effective Universal Heparin Antidote

Thrombosis, the formation of blood clots within a blood vessel, can lead to severe complications including pulmonary embolism, cardiac arrest, and stroke. The most widely administered class of anticoagulants is heparin-based anticoagulants such as unfractionated heparin, low-molecular weight heparins (LMWHs), and fondaparinux. Protamine is the only FDA-approved heparin antidote. Protamine has limited efficacy neutralizing LMWHs and no reversal activity against fondaparinux. The use of protamine can lead to complications, including excessive bleeding, hypotension, and hypersensitivity, and has narrow therapeutic window. In this work, a new concept in the design of a universal heparin antidote: switchable protonation of cationic ligands, is presented. A library of macromolecular polyanion inhibitors (MPIs) is synthesized and screened to identify molecules that can neutralize all heparins with high selectivity and reduced toxicity. MPIs are developed by assembling cationic binding groups possessing switchable protonation states onto a polymer scaffold. By strategically selecting the identity and modulating the density of cationic binding groups on the polymer scaffold, a superior universal heparin reversal agent is developed with improved heparin-binding activity and increased hemocompatibility profiles leading to minimal effect on hemostasis. The activity of this heparin antidote is demonstrated using in vitro and in vivo studies.

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.

Antiplatelet and anticoagulation strategies for left ventricular assist devices

Left ventricular assist devices (LVAD) have revolutionized the management of advanced heart failure. However, complications rates remain high, among which hemorrhagic and thrombotic complications are the most important. Antiplatelet and anticoagulation strategies form a cornerstone of LVAD management and may directly affect LVAD complications. Concurrently, LVAD complications influence anticoagulation and anticoagulation management. A thorough understanding of device, patient, and management, including anticoagulation and antiplatelet therapies, are important in optimizing LVAD outcomes. This article provides a comprehensive state of the art review of issues related to antiplatelet and anticoagulation management in LVADs. We start with a historical overview, the epidemiology and pathophysiology of bleeding and thrombotic complications in LVADs. We then discuss platelet and anticoagulation biology followed by considerations prior to, during, and after LVAD implantation. This is followed by discussion of anticoagulation and the management of thrombotic and hemorrhagic complications. Specific problems, including management of heparin-induced thrombocytopenia, anticoagulant reversal, novel oral anticoagulants, artificial heart valves, and noncardiac surgeries are covered in detail.

Expert consensus on the diagnosis and treatment of thrombocytopenia in adult critical care patients in China

Thrombocytopenia is a common complication of critical care patients. The rates of bleeding events and mortality are also significantly increased in critical care patients with thrombocytopenia. Therefore, the Critical Care Medicine Committee of Chinese People's Liberation Army (PLA) worked with Chinese Society of Laboratory Medicine, Chinese Medical Association to develop this consensus to provide guidance for clinical practice. The consensus includes five sections and 27 items: the definition of thrombocytopenia, etiology and pathophysiology, diagnosis and differential diagnosis, treatment and prevention.

Anticoagulation management strategies in heart transplantation

Anticoagulation before, during, and after heart transplantation (HT) presents unique challenges to clinicians. Bleeding and thrombotic morbidity continues to affect this patient population throughout all phases of the HT journey. Reversal is commonly required since patients are commonly bridged to HT with left ventricular assist devices, which require chronic anti platelet and anticoagulation. Caution must be exercised in patients requiring cardiopulmonary bypass during surgery who are at risk of complications from heparin induced thrombocytopenia. The reported incidence of venous thromboembolism following HT is high, particularly during the first post-HT year, most likely due to surgery, biopsies, specific immunosuppression (mTOR inhibitors) and immobilization. It is crucial to maintain long-term oral anticoagulation after the first venous thromboembolism event, especially when risk factors exist. A major issue, and one for which there remains considerable debate, is the optimal treatment of such complications, particularly upper extremity venous thrombosis. For both warfarin and the thrombin inhibitors or Factor Xa inhibitors, the clinician must determine potential drug interactions based on the HT drug regimen, and then develop a patient-specific management strategy.

Therapeutic plasma exchange for management of heparin-induced thrombocytopenia: Results of an international practice survey

INTRODUCTION

Anti-heparin/platelet factor 4 antibody immune complexes resulting from heparin-induced thrombocytopenia (HIT) are removed by therapeutic plasma exchange (TPE). We sought to define TPE in HIT practice patterns using an international survey.

METHODS

A 31-item online survey was disseminated through the American Society for Apheresis. After institutional duplicate responses were eliminated, a descriptive analysis was performed.

RESULTS

The survey was completed by 94 respondents from 78 institutions in 18 countries. Twenty-nine institutions (37%) used TPE for HIT (YES cohort) and 49 (63%) did not (NO cohort). Most NO respondents (65%) cited "no requests received" as the most common reason for not using TPE. Of the 29 YES respondents, 10 (34%) gave incomplete information and were excluded from the final analysis, leaving 19 responses. Of these, 18 (95%) treated ≤10 HIT patients over a 2-year period. The most common indications were cardiovascular surgery (CS; 63%) and HIT-associated thrombosis (HT; 26%). The typical plasma volume processed was 1.0 (63% CS and 58% HT). For CS, the typical replacement fluid was plasma (42%) and for HT, it was determined on an individual basis (32%). For CS, patients were treated with a set number of TPE procedures (37%) or laboratory/clinical response (37%). For HT, the number of TPE procedures typically depended on laboratory/clinical response (42%).

CONCLUSION

In a minority of responding institutions, TPE is most commonly used in HIT to prophylactically treat patients who will undergo heparin re-exposure during CS. Prospective studies are needed to more clearly define the role of TPE in HIT.

Anticoagulating patients with high-risk acquired thrombophilias

Antiphospholipid syndrome (APS), heparin-induced thrombocytopenia, and paroxysmal nocturnal hemoglobinuria are 3 acquired thrombophilias that carry a high risk of venous and arterial thromboembolism. Management of these conditions has largely included anticoagulation with a vitamin K antagonist after an initial period of a parenteral anticoagulant, for as long as the thrombotic risk is still present. The available evidence for the use of direct oral anticoagulants (DOACs) is limited and primarily consists of case series and cohort studies, which are summarized in this chapter. Randomized trials evaluating DOACs in patients with APS are reviewed. Further research is needed prior to widely adopting DOACs for use in these high-risk acquired thrombophilias; however, there may be selected low-risk subgroups where DOAC use is possible after careful consideration and patient discussion.

Anticoagulating patients with high-risk acquired thrombophilias

Antiphospholipid syndrome (APS), heparin-induced thrombocytopenia, and paroxysmal nocturnal hemoglobinuria are 3 acquired thrombophilias that carry a high risk of venous and arterial thromboembolism. Management of these conditions has largely included anticoagulation with a vitamin K antagonist after an initial period of a parenteral anticoagulant, for as long as the thrombotic risk is still present. The available evidence for the use of direct oral anticoagulants (DOACs) is limited and primarily consists of case series and cohort studies, which are summarized in this chapter. Randomized trials evaluating DOACs in patients with APS are reviewed. Further research is needed prior to widely adopting DOACs for use in these high-risk acquired thrombophilias; however, there may be selected low-risk subgroups where DOAC use is possible after careful consideration and patient discussion.