Techniques and applications of perioperative therapeutic plasma exchange

Effect of Preoperative Therapeutic Plasma Exchange With Albumin Replacement Before Kidney Transplant on Intraoperative Coagulation Measured By the Thrombelastograph (TEGR 6s): A Case Report

Anesthesiologists should be aware of the coagulation implications of therapeutic plasma exchange (TPE) with albumin replacement for desensitization of kidney transplant (KT) recipients. We describe a case where the final preoperative TPE was performed with albumin. A TEGR 6s demonstrated defects in fibrinogen component to clot strength. With surgical oozing noted and the fibrinogen defect, cryoprecipitate was administered. Thereafter, fibrinogen contribution to clot strength normalized, coinciding with clinical hemostasis. With the increased use of TPE to reduce antibodies in KT recipients, visco-elastic testing may assist in the identification of coagulation defects when plasma is not used as replacement fluid.

Management of the sensitized heart transplant candidate

PURPOSE OF REVIEW

For sensitized heart transplant candidates who have antibodies to human leukocyte antigens (HLA), finding a suitable donor can be challenging and can lead to adverse waitlist outcomes. In recent years, the number of sensitized patients awaiting heart transplantation has increased likely due to the use of durable and mechanical circulatory support as well as increasing number of candidates with underlying congenital heart disease.

RECENT FINDINGS

Advances in the assessment of HLA antibodies allow for identification of heart transplant candidates who may benefit from desensitization strategies to widen the donor pool and mitigate the risk of adverse posttransplant outcomes.

SUMMARY

Antibody sensitization is a barrier to successful heart transplantation and strategies to identify sensitized patients, stratify their risk, and mitigate this risk through desensitization is crucial to optimize the quality of life and survival of HT recipients.

Detection and management of HLA sensitization in candidates for adult heart transplantation

Heart transplantation (HT) remains the preferred therapy for patients with advanced heart failure. However, for sensitized HT candidates who have antibodies to human leukocyte antigens , finding a suitable donor can be challenging and can lead to adverse waitlist outcomes. In recent years, the number of sensitized patients awaiting HT has increased likely due to the use of durable and mechanical circulatory support as well as increasing number of candidates with underlying congenital heart disease. This State-of-the-Art review discusses the assessment of human leukocyte antigens antibodies, potential desensitization strategies including mechanisms of action and specific protocols, the approach to a potential donor including the use of complement-dependent cytotoxicity, flow cytometry, and virtual crossmatches, and peritransplant induction management.

Effect on haemostasis of different replacement fluids during therapeutic plasma exchange—A comparative multicentre observational study

INTRODUCTION

Therapeutic plasma exchange (TPE) is used for several chronic conditions with little evidence on the efficacy and safety of different choice of replacement fluid. Measurement of haemostasis, particularly in vitro thrombin generation, could play a role in determining the immediate efficacy of different fluid replacement.

AIM

To determine the impact of different TPE replacement fluid regimens on haemostatic assays.

METHODS

Prospective observational multi-centre cohort study in adult patients 18 years and older evaluating haemostatic changes between four different TPE regimens: (1) 5% human albumin solution (Alb) only, (2) 50:50 mix of 5% Alb + modified gelatin, (3) 70:30 mix of 5% Alb and normal saline (NS), and (4) solvent-detergent, virus-inactivated fresh frozen plasma (FFP) (either alone or combined with other fluids). Twenty-one haemostasis variables were analysed (procoagulant, anticoagulant and fibrinolytic factors) pre and post TPE sessions, including in vitro thrombin generation. Linear mixed modelling and canonical discriminant analyses were used to examine the effect of TPE fluid type on haemostatic variables.

RESULTS

A total of 31 patients with up to 5 TPE sessions each (131 sessions in total) were enrolled. Out of 21 markers analysed using linear mixed modelling, the main effects of fluid type were found to be significant for 19 markers (P < 0.05), excluding plasminogen activator inhibitor-1 antigen and thrombin-anti-thrombin. Multivariate Analysis of Variance showed significant differences between the fluid types (Wilks' lambda = 0.07; F_63,245.61  = 5.50; P < 0.0001) and this was supported by a canonical discriminant analysis, which identified the 4 most discriminating markers for fluid types as thrombin generation (lag-time, time-to Peak), fibrinogen and Factor V. In our analyses, the effect of FFP on haemostasis was significantly greater compared with other fluid types. Of the non-FFP fluids, 5% Alb + NS had a lower effect on haemostasis compared to other fluid types (Alb and modified gelatin + 5% Alb).

CONCLUSION

Thrombin generation and fibrinogen discriminated better the effect of different TPE fluids on haemostasis and should be considered as potential markers to evaluate the immediate haemostatic effect of TPE procedures. The use of NS as a TPE replacement fluid had a distinctive impact on thrombin generation and fibrinogen responses compared to other non-FFP fluids.

Severe thrombotic events associated with pre-procedural interruption of anticoagulation in systemic lupus erythematosus with secondary antiphospholipid syndrome: Cases and literature review

BACKGROUND

The American College of Chest Physicians (ACCP) and National Institutes for health and care Excellence in the United Kingdom (NICE) recommend that patients who are high risk for thrombotic events but require cessation of oral anticoagulation with warfarin, due to bleeding risk of a planned procedure, undergo bridging therapy with heparin. However, those conditions which are considered high risk are not universal, nor do guidelines differentiate between low molecular weight heparin (LMWH) and unfractionated heparin. Triple positive antiphospholipid syndrome (APS) is a thrombophilic state with a very high risk for thrombotic events during periods of anticoagulation cessation. Patients with secondary antiphospholipid syndrome in the setting of SLE may be at an even greater risk of thrombotic events during the perioperative period.

PURPOSE

Along with a review of the literature for perioperative management in APS we present three cases of triple positive secondary APS in systemic lupus erythematosus (SLE) patients who had severe thrombotic complications after cessation of their oral anticoagulation despite being bridged with LWMH.

CONCLUSION

Given the severity and rapidity of thrombotic complications with low molecular weight heparin bridging, we propose that all patients with triple positive APS, especially secondary APS with SLE should undergo bridging therapy with intravenous UFH to reduce time without anticoagulation and minimize risk of thrombotic complications. Furthermore, we propose that NICE include APS in the list of medical conditions which are high risk for thrombotic complications and require bridging therapy.

Serious acid-base disorder or life-threatening arrhythmia in patients with ABO-incompatible liver transplantation who received therapeutic plasma exchange - A report of two cases

Background

Excessive citrate load during therapeutic plasma exchange (TPE) can cause metabolic alkalosis with compensatory hypercarbia and electrolyte disturbances. If TPE is required immediately before ABO-incompatible (ABOi) liver transplant (LT) surgery, metabolic derangement and severe electrolyte disturbance could worsen during LT anesthesia.

Case

We report two ABOi LT cases who received TPE on the day of surgery because isoagglutinin titers did not be dropped below 1:8. One case had a surprisingly high metabolic alkalosis with a pH of 7.73 immediately after tracheal intubation because of hyperventilation during mask bagging. The other experienced sudden ventricular tachycardia and blood pressure drop after surgical incision accompanied with severe hypokalemia of 1.8 mmol/L despite supplementation with potassium.

Conclusions

Special attention should be paid to patients who just completed TPE the operative day morning as they are vulnerable to severe acid-base disturbances and life-threatening ventricular arrhythmias in ABOi LT.

Plasmapheresis for Management of Antiphospholipid Syndrome in the Neurosurgical Patient

BACKGROUND AND IMPORTANCE

Antiphospholipid syndrome (APS) is an autoimmune disorder associated with a hypercoagulable state and increased risk of intraoperative and postoperative thrombosis. Few neurosurgical studies have examined the management of these patients, though the standard of care in most other disciplines involves the use of anticoagulation therapy. However, this is associated with risks such as hemorrhage, thrombosis due to warfarin withdrawal, and is not compatible with operative intervention.

CLINICAL PRESENTATION

We report the cases of 2 antiphospholipid positive patients who were on anticoagulant therapy and underwent surgical bypasses and received perioperative management with plasmapheresis. The first was a 44-yr-old woman who presented with worsening vision, recurring headaches, and a known left internal carotid artery aneurysm that was unsuccessfully treated twice via extracranial to intracranial (ECIC) bypass at another institution. Preoperative tests at our institution revealed elevated beta 2 glycoprotein 1 IgA autoantibodies. The second case was a 24-yr-old woman with previously diagnosed APS, who presented for surgical evaluation of moyamoya disease after sustaining recurrent left hemispheric strokes. Both cases were managed with perioperative plasmapheresis to avoid the need for anticoagulation during the perioperative period, and both underwent successful ECIC bypass procedures without perioperative ischemic or hemorrhagic complications.

CONCLUSION

Management of neurosurgical patients with APS can be a precarious proposition. We describe the successful use of plasmapheresis and antiplatelet therapy to better manage patients undergoing neurosurgical procedures, specifically ECIC bypass, and feel this approach can be considered in future cases.

Literature review of apheresis procedures performed perioperatively in cardiac surgery for ASFA category indications

BACKGROUND

Perioperative therapeutic plasma exchange in patients with cardiovascular diseases poses several challenges, including alterations in intravascular volume, serum electrolytes, the coagulation cascade, and drug pharmacokinetics.

METHODS

This review article summarizes different indications of plasma exchange for patients requiring cardiac surgery based on reported case reports and case series.

RESULTS

The most common reported indication is plasma exchange for the management of allosensitized cardiac transplant candidate patients in combination with immunosuppressive regimens, which increases the likelihood of obtaining a cross-match-negative allograft, improving post-transplant clinical outcome. The second most common indication is for patients with a history of heparin-induced thrombocytopenia syndrome that permits the use of heparin in cardiopulmonary bypass in an urgent cardiac surgery. Less common indications are restoration of clotting factors for patients with congenital bleeding disorders or removal of cold agglutinins. No severe complications were described in reported cases.

CONCLUSION

Therapeutic plasma exchange is an effective and safe procedure that could be performed preoperatively and intraoperatively in urgent cardiac surgery for the management of antibody-mediated disorders including allosensitized cardiac transplant candidate patients or patients with heparin-induced thrombocytopenia syndrome.

Prevalent metabolic derangement and severe thrombocytopenia in ABO-incompatible liver recipients with pre-transplant plasma exchange

Desensitisation with therapeutic plasma exchange (TPE) is essential for ABO-incompatible (ABO-I) liver transplants (LTs). However, excessive citrate load and coagulation disturbances after TPE have been poorly studied, in particular in cirrhotic patients with hypocapnic alkalosis, metabolic compensation and electrolyte imbalances. We retrospectively evaluated 1123 consecutive LT recipients (923 ABO-compatible [ABO-C], 200 ABO-I) from November 2008 to May 2015. TPE was generally performed a day before LT and blood sampling was performed before anaesthesia induction. We performed propensity score matching (PSM) and inverse probability treatment weighting (IPTW) analyses. In 199 PSM pairs, metabolic alkalosis was prevalent in ABO-I LT recipients (expectedly due to citrate conversion) with higher pH ≥ 7.50 (IPTW-adjusted odds ratio [aOR] = 2.23) than in ABO-C LT recipients. With increasing cirrhosis severity, the arterial pH and bicarbonate levels showed dose-dependent relationships, whereas mild hypoxaemia was more prevalent in ABO-I LT recipients. ABO-I LT recipients exhibited worsened hypokalaemia ≤3.0 mmol/l (17.6%, aOR = 1.44), hypomagnesaemia ≤1.7 mg/dl (27.6%, aOR = 3.43) and thrombocytopenia <30,000/µl (19.1%, aOR = 2.26) confirmed by lower maximal clot firmness (P = 0.001) in rotational thromboelastometry (EXTEM), which necessitated platelet transfusions. Preoperative identification of these change may prevent worsening of severe electrolyte disturbances and thrombocytopenia for optimal LT anaesthesia.

Therapeutic plasma exchange in heart transplantation: role of coagulation assessment with thromboelastometry

Therapeutic plasma exchange (TPE) is a potentially life-saving procedure which effectively removes donor-specific human leukocyte antigen (HLA) antibodies from the bloodstream, allowing critically ill heart transplant recipients to receive a donor organ with less wait time, and reducing the risk of acute organ rejection. The bulk of coagulation factors is initially removed from the blood during TPE using albumin and is later replaced with allogeneic plasma. Coagulopathy may develop during TPE and then can persist due to intraoperative blood loss and hemodilution during surgery and cardiopulmonary bypass. We hereby describe the utility of rotational thromboelastometry to assess rapid coagulation changes during TPE and subsequent heart transplant (HT) surgery.

Assessment of Hemostasis after Plasma Exchange Using Rotational Thrombelastometry (ROTEM)

Background

Therapeutic plasma exchange (TPE)-based protocols immediately before cadaveric donor kidney transplantation have been extensively used in highly sensitized recipients. Plasma is generally preferred over human albumin as replacement fluid to avoid depletion of coagulation factors and perioperative bleeding. The aim of this study was to estimate bleeding risk after TPE replaced with albumin using rotational thromboelastography (ROTEM).

Methodology

Ten patients without overt coagulation abnormalities underwent TPE. Standard laboratory coagulation tests (thromboplastin time, activated partial thromboplastin time (aPTT), international normalized ratio (INR), thrombin clotting time, fibrinogen levels and antithrombin activity) were compared with thrombelastometry analysis (EXTEM and INTEM tests) before and after TPE.

Principal Findings

TPE significantly reduced fibrinogen levels (482 ± 182 vs. 223 ± 122 mg/dL), antithrombin activity (103 ± 11 vs. 54 ± 11 %), and prolonged aPTT (28 ± 3 vs. 45 ± 8 s), thromboplastin time (108 ± 11 vs. 68 ± 11 %), INR (0.95 ± 0.06 vs. 1.25 ± 0.16), and thrombin clotting time (18 ± 2 vs. 20 ± 3 s). INTEM and EXTEM analyses revealed significantly prolonged clot-formation time and reduced maximum clot firmness.

Conclusions/Significance

TPE replaced with albumin induces significant changes in global hemostasis parameters thus potentially increasing bleeding risk. Therefore, pretransplant TPE should be considered carefully in indicated patients before kidney transplantation. The role of the ROTEM point-of-care test to estimate the risk of bleeding in renal transplantation needs to be evaluated in further studies.