Management of a Patient with Lupus Anticoagulant and Antiphospholipid Syndrome for Off-Pump Coronary Artery Bypass Grafting Using the Hepcon® System

Efficacy of the Hepcon system in reducing hemorrhagic and thrombotic complications in antiphospholipid syndrome patients undergoing cardiac surgery

INTRODUCTION

Patients with Antiphospholipid Syndrome (APS) undergoing cardiopulmonary bypass (CPB) surgery are at increased risk for thrombotic and hemorrhagic complications. Anticoagulation during CPB is typically monitored with activated clotting time (ACT) which may be falsely prolonged in patients with APS. The Hepcon Hemostasis Management System quantitatively determines the whole blood heparin concentration through heparin/protamine titration.

METHODS

This was a retrospective study of APS patients who underwent cardiac surgery requiring CPB at the Cleveland Clinic between April 2013, and July 2020. The primary endpoint was the composite rate of hemorrhagic or thromboembolic complications per surgical case in patients monitored by Hepcon versus patients monitored by ACT. Secondary endpoints were median volume of chest tube output and packed red blood cell (PRBC) transfusion within the first three post-operative days.

RESULTS

43 patients were included. 20 (47%) patients were monitored using Hepcon while 23 (53%) were monitored using ACT. For the primary endpoint of rate of thromboembolic or hemorrhagic complications per surgical case, there was no statistically significant difference between the Hepcon and ACT groups (HMS, 6/20 [30%]; ACT, 7/23 [30%]; p = >0.99). For the secondary endpoints, there was no statistically significant difference in median post-operative chest tube output (780 mL vs. 850 mL; p = 0.88) and median post-operative PRBC transfusion (1 unit vs. 0 unit; p = 0.28) between the Hepcon and ACT groups, respectively.

CONCLUSION

There was no difference in the composite outcome of thrombotic or hemorrhagic complications in patients monitored by Hepcon versus those monitored by ACT.

Antiphospholipid Syndrome and Cardiac Bypass: The Careful Balance between Clotting and Bleeding

Antiphospholipid syndrome (APS) is an acquired autoimmune condition characterized by the presence of antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibody, and anti-β₂ glycoprotein-I antibody) which leads to clinical thrombosis via a multifactorial mechanism of action. Despite the propensity to form clot in vivo, these antibodies interfere with the assembly of the prothrombinase complex on phospholipids in in vitro assays, leading to prolongation of activated clotting time and activated partial thromboplastin time. This disconnect between what occurs in vivo and in vitro makes monitoring anticoagulation during cardiac surgery particularly complex. We present a patient with APS undergoing coronary artery bypass grafting with cardiopulmonary bypass. We delineate our strategy for managing anticoagulation in the presence of this syndrome using the Hepcon Hemostasis Management System Plus (Medtronic, Inc. Minneapolis, MN) device by targeting whole blood heparin concentration to monitor anticoagulation.

Anaesthetic considerations for patients with antiphospholipid syndrome undergoing non-cardiac surgery

Antiphospholipid syndrome (APS) is an acquired thrombotic autoimmune disorder that is clinically characterized by the development of thrombosis and obstetric morbidities in patients with antiphospholipid antibodies. Due to hypercoagulability, the focus of management is anticoagulation for the prevention of thrombosis and its recurrence. When such patients undergo surgery, however, the underlying risk of thrombosis increases as a result of anticoagulant withdrawal, immobilization, and/or intimal injury. Conversely, there is also an increased risk of bleeding due to thrombocytopaenia, possible disseminated intravascular coagulation, or progression to catastrophic APS, as a result of excessive anticoagulation, surgery, and infection. Measures for appropriate perioperative anticoagulation are discussed in this review, as well as anaesthetic considerations for preventing perioperative complications in patients with APS undergoing non-cardiac surgery.

A case of acute myocardial infarction during perioperative period of non-cardiac surgery in a patient with antiphospholipid syndrome and a history of coronary artery bypass surgery

A 65-year-old woman underwent coronary artery bypass surgery and was diagnosed with antiphospholipid syndrome (APS) at the same time in 1985. She was admitted to our hospital to undergo mastectomy for left breast cancer in 2012. She was put on intravenous infusion of heparin and stopped receiving both antiplatelet agents and warfarin. The operation was performed without complications, and antithrombotic therapy was restarted one day after the operation. On day 6 postoperative, she complained of sudden chest pain and on examination she was diagnosed with acute myocardial infarction. The culprit lesion was in a saphenous vein graft and coronary intervention was performed. <Learning objective: Antithrombotic therapy for patients with APS is complicated because of prolonged baseline activated partial thromboplastin time (aPTT). An effective perioperative antithrombotic therapy for APS patients who have a history of coronary artery disease and have undergone non-cardiac surgery has not yet been established. A safe strategy for such a therapy should therefore be discussed.>.

Review article: heparin sensitivity and resistance: management during cardiopulmonary bypass

Heparin resistance during cardiac surgery is defined as the inability of an adequate heparin dose to increase the activated clotting time (ACT) to the desired level. Failure to attain the target ACT raises concerns that the patient is not fully anticoagulated and initiating cardiopulmonary bypass may result in excessive activation of the hemostatic system. Although antithrombin deficiency has generally been thought to be the primary mechanism of heparin resistance, the reasons for heparin resistance are both complex and multifactorial. Furthermore, the ACT is not specific to heparin's anticoagulant effect and is affected by multiple variables that are commonly present during cardiac surgery. Due to these many variables, it remains unclear whether decreased heparin responsiveness as measured by the ACT represents inadequate anticoagulation. Nevertheless, many clinicians choose a target ACT to assess anticoagulation, and interventions aimed at achieving the target ACT are routinely performed in the setting of heparin resistance. Treatments for heparin resistance/alterations in heparin responsiveness include additional heparin or antithrombin supplementation. In this review, we discuss the variability of heparin potency, heparin responsiveness as measured by the ACT, and the current management of heparin resistance.

Lupus Anticoagulant, Antiphospholipid Syndrome and Cardiac Surgery

The presence of lupus anticoagulant and the related condition antiphospholipid syndrome present a challenge in cardiac surgery where measured anticoagulation may not reflect the in vivo patient status of hypercoagulation. We report the successful management of a patient with lupus anticoagulant presenting for aortic valve replacement and coronary revascularisation. We used heparin for anticoagulation, specialised additional tests of anticoagulation and a reduced protamine dose. We also used tranexamic acid. The clinical problems with anticoagulation in patients with lupus anticoagulant include anticoagulant choice, measurement of adequate anticoagulation, antifibrinolytic usage, protamine dosing and blood product transfusion.