Clinical outcomes of cardiac surgery patients undergoing therapeutic plasma exchange for heparin-induced thrombocytopenia

2024 EACTS/EACTAIC/EBCP Guidelines on cardiopulmonary bypass in adult cardiac surgery

Clinical practice guidelines consolidate and evaluate all pertinent evidence on a specific topic available at the time of their formulation. The goal is to assist physicians in determining the most effective management strategies for patients with a particular condition. These guidelines assess the impact on patient outcomes and weigh the risk-benefit ratio of various diagnostic or therapeutic approaches. While not a replacement for textbooks, they provide supplementary information on topics relevant to current clinical practice and become an essential tool to support the decisions made by specialists in daily practice. Nonetheless, it is crucial to understand that these recommendations are intended to guide, not dictate, clinical practice, and should be adapted to each patient's unique needs. Clinical situations vary, presenting a diverse array of variables and circumstances. Thus, the guidelines are meant to inform, not replace, the clinical judgement of healthcare professionals, grounded in their professional knowledge, experience and comprehension of each patient's specific context. Moreover, these guidelines are not considered legally binding; the legal duties of healthcare professionals are defined by prevailing laws and regulations, and adherence to these guidelines does not modify such responsibilities. The European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Cardiothoracic Anaesthesiology and Intensive Care (EACTAIC) and the European Board of Cardiovascular Perfusion (EBCP) constituted a task force of professionals specializing in cardiopulmonary bypass (CPB) management. To ensure transparency and integrity, all task force members involved in the development and review of these guidelines submitted conflict of interest declarations, which were compiled into a single document available on the EACTS website (https://www.eacts.org/resources/clinical-guidelines). Any alterations to these declarations during the development process were promptly reported to the EACTS, EACTAIC and EBCP. Funding for this task force was provided exclusively by the EACTS, EACTAIC and EBCP, without involvement from the healthcare industry or other entities. Following this collaborative endeavour, the governing bodies of EACTS, EACTAIC and EBCP oversaw the formulation, refinement, and endorsement of these extensively revised guidelines. An external panel of experts thoroughly reviewed the initial draft, and their input guided subsequent amendments. After this detailed revision process, the final document was ratified by all task force experts and the leadership of the EACTS, EACTAIC and EBCP, enabling its publication in the European Journal of Cardio-Thoracic Surgery, the British Journal of Anaesthesia and Interdisciplinary CardioVascular and Thoracic Surgery. Endorsed by the EACTS, EACTAIC and EBCP, these guidelines represent the official standpoint on this subject. They demonstrate a dedication to continual enhancement, with routine updates planned to ensure that the guidelines remain current and valuable in the ever-progressing arena of clinical practice.

High-dose intravenous immunoglobulin G and usual heparin anticoagulation for urgent cardiac surgery in a patient with severe autoimmune heparin-induced thrombocytopenia

A 56-year-old woman required urgent cardiac surgery for Streptococcus mitis mitral valve infective endocarditis complicated by severe autoimmune heparin-induced thrombocytopenia (aHIT). We reasoned that the combination of high-dose intravenous immunoglobulin G (IVIG; to mitigate aHIT antibody-mediated platelet activation in the presence of heparin) together with the high concentrations of heparin attained during cardiac surgery (which typically produces less platelet activation in vitro vs usual therapeutic heparin concentrations) might prove effective. Accordingly, our patient underwent cardiac surgery with heparin following high-dose IVIG (1 g/kg × 2) without intra- or postoperative thrombosis. Serial serotonin release assays, using blood obtained pre-/post-IVIG, showed minimal platelet activation (∼30% serotonin release) post-IVIG at heparin concentrations typically obtained during cardiac surgery (2-5 U/mL) and significantly less than pre-IVIG serum in heparin's absence (∼85% serotonin release). In the setting of urgent cardiac surgery, preoperative high-dose IVIG appears to be a reasonable strategy to reduce platelet-activating effects of heparin-induced thrombocytopenia (including aHIT) antibodies, permitting safe use of standard intraoperative heparin dosing.

Approaches to management of HIT in complex scenarios, including cardiac surgery

Although heparin-induced thrombocytopenia (HIT) presents management challenges for any population, it adds complexity to the management of certain patient populations, including those undergoing cardiac surgery and those with refractory HIT and/or acute bleeding. For each of these scenarios, we review alternative management strategies when standard therapies-heparin cessation and the initiation of a nonheparin anticoagulant-are either insufficient or not practicable. In patients with HIT undergoing cardiac surgery, we review the clinical experience for heparin reexposure using therapeutic plasma exchange (TPE) or antiplatelet therapy. In patients with refractory HIT despite adequate nonheparin anticoagulation, we address the use of intravenous immune globulin, TPE, and rituximab. Finally, in patients with active bleeding, we discuss bleeding management and the risks associated with platelet transfusion. Although they may facilitate a patient-centered approach, most of these strategies are supported by limited evidence.

Efficacy of Therapeutic Plasma Exchange or Cangrelor as an Adjunctive Strategy to Facilitate Cardiopulmonary Bypass in Patients with Heparin-Induced Thrombocytopenia: A Systematic Review and Meta-Analysis

OBJECTIVE

Conduct a systematic review and meta-analysis of the efficacy of therapeutic plasma exchange (TPE) or intravenous cangrelor to prevent thromboembolism in patients with heparin-induced thrombocytopenia (HIT) who undergo cardiopulmonary bypass (CPB) with heparin.

DESIGN

Systematic review and meta-analysis.

SETTING

N/A.

PARTICIPANTS

Adults having cardiac surgery with a history of HIT who received preoperative or intraoperative TPE or intravenous cangrelor as an adjunct to CPB with heparin.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: A systematic review was performed using MEDLINE, PubMed, and Google Scholar. The primary outcome was avoidance of thromboembolism (venous or arterial) during or after CPB. Proportional meta-analysis with a random effects model was used to calculate a weighted-pooled proportion/efficacy for the study's primary outcome. Fifty-seven patients in 17 reports received TPE as an adjunctive treatment to prevent HIT-related thrombosis related to heparinization during CPB and 3 (5.3%) experienced thrombosis. Proportional meta-analysis suggested a weighted-pooled freedom from perioperative thromboembolism rate of 91.0% (95% CI 82.6%-96.9%). Fifteen patients in 6 reports received intravenous cangrelor as an adjunctive treatment to prevent HIT-related thrombosis related to heparinization during CPB and 2 (13.3%) experienced thrombosis. Proportional meta-analysis suggested a weighted-pooled freedom from perioperative thromboembolism rate of 83.0% (95% CI 61.2%- 97.6%).

CONCLUSIONS

TPE and cangrelor are feasible strategies to prevent thromboembolism in adults with HIT who require CPB with heparin. Given the relatively small number of cases in the published literature and a high likelihood for publication and detection biases, prudence remains warranted when using these strategies.

Bleeding recurrence risk among hospitalized patients undergoing therapeutic plasma exchange: a multi-center study

BACKGROUND

In hospitalized patients undergoing therapeutic plasma exchange (TPE), it is not known how TPE-associated bleeding risk is impacted by a prior bleeding episode. Therefore, to assess the prevalence and predictors of bleeding recurrence, we analyzed data from the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III).

MATERIALS AND METHODS

Using a retrospective cross-sectional analysis of REDS-III public use files, we identified hospitalized adults who had a major bleeding episode prior to their first TPE procedure. Patients were classified into two cohorts based on bleeding recurrence (no-recurrence vs recurrence). After identifying potential predictors, we used multiple imputation by chained equations to impute variables with <30% missing data. Variable selection was optimized using a 10-fold cross validated least absolute shrinkage and selection operator. Final predictors were identified by fitting a logistic regression model.

RESULTS

In 310 patients with major bleeding prior to TPE initiation, bleeding recurred in 121 (39.0%). We identified the following seven unique predictors: 1) >10 TPE procedures (OR 2.23); 2) intensive care unit stay (OR 1.35); 3) thrombocytopenia (OR 1.26); 4) surgery (OR 1.22); 5) hepatic disease (OR 1.21); 6) 6-10 TPE procedures (OR 1.04); and 7) Asian race (OR 1.01). We also identified the following five interactions: 1) surgery and therapeutic anticoagulation (OR 1.50); 2) 6-10 TPE procedures and therapeutic anticoagulation (OR 1.05); 3) 6-10 TPE procedures and antiplatelets (OR 1.02); 4) >10 TPE procedures and antiplatelets (OR 1.00); and 5) albumin-only TPE and antiplatelets (OR 0.53). When assessed for adjusted performance, the prediction model had a C-statistic of 0.617 (95% CI 0.613-0.619) and Brier Score of 0.342 (95% CI 0.340-0.347).

DISCUSSION

In this study assessing predictors of bleeding recurrence among hospitalized patients undergoing TPE, we identified seven variables and five interactions. These findings should be validated in future studies.

Therapeutic strategies in FcγIIA receptor-dependent thrombosis and thromboinflammation as seen in heparin-induced thrombocytopenia (HIT) and vaccine-induced immune thrombocytopenia and thrombosis (VITT)

INTRODUCTION

Fcγ-receptors (FcγR) are membrane receptors expressed on a variety of immune cells, specialized in recognition of the Fc part of immunoglobulin G (IgG) antibodies. FcγRIIA-dependent platelet activation in platelet factor 4 (PF4) antibody-related disorders have gained major attention, when these antibodies were identified as the cause of the adverse vaccination event termed vaccine-induced immune thrombocytopenia and thrombosis (VITT) during the COVID-19 vaccination campaign. With the recognition of anti-PF4 antibodies as cause for severe spontaneous and sometimes recurrent thromboses independent of vaccination, their clinical relevance extended far beyond heparin-induced thrombocytopenia (HIT) and VITT.

AREAS COVERED

Patients developing these disorders show life-threatening thromboses, and the outcome is highly dependent on effective treatment. This narrative literature review summarizes treatment options for HIT and VITT that are currently available for clinical application and provides the perspective toward new developments.

EXPERT OPINION

Nearly all these novel approaches are based on in vitro, preclinical observations, or case reports with only limited implementation in clinical practice. The therapeutic potential of these approaches still needs to be proven in larger cohort studies to ensure treatment efficacy and long-term patient safety.

Research priorities for therapeutic plasma exchange in critically ill patients

Therapeutic plasma exchange (TPE) is a therapeutic intervention that separates plasma from blood cells to remove pathological factors or to replenish deficient factors. The use of TPE is increasing over the last decades. However, despite a good theoretical rationale and biological plausibility for TPE as a therapy for numerous diseases or syndromes associated with critical illness, TPE in the intensive care unit (ICU) setting has not been studied extensively. A group of eighteen experts around the globe from different clinical backgrounds used a modified Delphi method to phrase key research questions related to "TPE in the critically ill patient". These questions focused on: (1) the pathophysiological role of the removal and replacement process, (2) optimal timing of treatment, (3) dosing and treatment regimes, (4) risk-benefit assumptions and (5) novel indications in need of exploration. For all five topics, the current understanding as well as gaps in knowledge and future directions were assessed. The content should stimulate future research in the field and novel clinical applications.

Management of severe peri-operative bleeding: Guidelines from the European Society of Anaesthesiology and Intensive Care: Second update 2022

BACKGROUND

Management of peri-operative bleeding is complex and involves multiple assessment tools and strategies to ensure optimal patient care with the goal of reducing morbidity and mortality. These updated guidelines from the European Society of Anaesthesiology and Intensive Care (ESAIC) aim to provide an evidence-based set of recommendations for healthcare professionals to help ensure improved clinical management.

DESIGN

A systematic literature search from 2015 to 2021 of several electronic databases was performed without language restrictions. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to assess the methodological quality of the included studies and to formulate recommendations. A Delphi methodology was used to prepare a clinical practice guideline.

RESULTS

These searches identified 137 999 articles. All articles were assessed, and the existing 2017 guidelines were revised to incorporate new evidence. Sixteen recommendations derived from the systematic literature search, and four clinical guidances retained from previous ESAIC guidelines were formulated. Using the Delphi process on 253 sentences of guidance, strong consensus (>90% agreement) was achieved in 97% and consensus (75 to 90% agreement) in 3%.

DISCUSSION

Peri-operative bleeding management encompasses the patient's journey from the pre-operative state through the postoperative period. Along this journey, many features of the patient's pre-operative coagulation status, underlying comorbidities, general health and the procedures that they are undergoing need to be taken into account. Due to the many important aspects in peri-operative nontrauma bleeding management, guidance as to how best approach and treat each individual patient are key. Understanding which therapeutic approaches are most valuable at each timepoint can only enhance patient care, ensuring the best outcomes by reducing blood loss and, therefore, overall morbidity and mortality.

CONCLUSION

All healthcare professionals involved in the management of patients at risk for surgical bleeding should be aware of the current therapeutic options and approaches that are available to them. These guidelines aim to provide specific guidance for bleeding management in a variety of clinical situations.

Coagulation and Transfusion Updates From 2021

2021 and the COVID 19 pandemic have brought unprecedented blood shortages worldwide. These deficits have propelled national efforts to reduce blood usage, including limiting elective services and accelerating Patient Blood Management (PBM) initiatives. A host of research dedicated to blood usage and management within cardiac surgery has continued to emerge. The intent of this review is to highlight this past year's research pertaining to PBM and COVID-19-related coagulation changes.

Hemostatic effects of therapeutic plasma exchange: A concise review

Therapeutic plasma exchange (TPE) alters the hemostatic balance. Contributing to TPE's hemostatic effects is the mechanical processing of blood in the extracorporeal circuit, circuit anticoagulant, type of replacement fluid, TPE schedule and number of procedures, TPE timing relative to invasive procedures, and removal of nontargeted components such as platelets, coagulation proteins, and cytokines. Although TPE's hemostatic effects are well established, how it impacts the bleeding risk is not clearly understood. In this concise review, we describe the effects of the above TPE-related factors on hemostatic balance, present data on the effects of TPE on blood hemostasis, including its effects on platelet counts and clotting assays, and review the literature on the impact of TPE-induced hemostatic changes on TPE-associated bleeding events. Finally, we discuss risk factors associated with bleeding during TPE and review the literature on TPE-associated hemostatic effects in the pediatric population.

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.

Heparin-induced thrombocytopenia and cardiovascular surgery

Clinicians generally counsel patients with a history of heparin-induced thrombocytopenia (HIT) to avoid heparin products lifelong. Although there are now many alternative (nonheparin) anticoagulants available, heparin avoidance remains challenging for cardiac surgery. Heparin is often preferred in the cardiac surgery setting based on the vast experience with the agent, ease of monitoring, and reversibility. To "clear" a patient with a history of HIT for cardiac surgery, hematologists must first confirm the diagnosis of HIT, which can be challenging due to the ubiquity of heparin exposure and frequency of thrombocytopenia in patients in the cardiac intensive care unit. Next, the "phase of HIT" (acute HIT, subacute HIT A/B, or remote HIT) should be established based on platelet count, immunoassay for antibodies to platelet factor 4/heparin complexes, and a functional assay (eg, serotonin release assay). As long as the HIT functional assay remains positive (acute HIT or subacute HIT A), cardiac surgery should be delayed if possible. If surgery cannot be delayed, an alternative anticoagulant (preferably bivalirudin) may be used. Alternatively, heparin may be used with either preoperative/intraoperative plasma exchange or together with a potent antiplatelet agent. The optimal strategy among these options is not known, and the choice depends on institutional experience and availability of alternative anticoagulants. In the later phases of HIT (subacute HIT B or remote HIT), brief intraoperative exposure to heparin followed by an alternative anticoagulant as needed in the postoperative setting is recommended.

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.