bivalirudin and Purpura--Thrombocytopenic--Idiopathic

Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder characterized by heparin-dependent antibodies that activate platelets (PLTs) via PLT FcγIIa receptors. "Autoimmune" HIT (aHIT) indicates a HIT subset where thrombocytopenia progresses or persists despite stopping heparin; aHIT sera activate PLTs strongly even in the absence of heparin (heparin-independent PLT-activating properties). Affected patients are at risk of severe complications, including dual macro- and microvascular thrombosis leading to venous limb gangrene. High-dose intravenous immunoglobulin (IVIG) offers an approach to interrupt heparin-independent PLT-activating effects of aHIT antibodies.. A 78-year-old male who underwent cardiopulmonary bypass for aortic dissection developed aHIT, disseminated intravascular coagulation, and deep vein thrombosis; progression to venous limb gangrene occurred during partial thromboplastin time (PTT)-adjusted bivalirudin infusion (underdosing from "PTT confounding"). Thrombocytopenia recovered with high-dose IVIG, although the PLT count increase began only after the third dose of a 5-day IVIG regimen (0.4 g/kg/day × 5 days). We reviewed case reports and case series of IVIG for treating HIT, focusing on various IVIG dosing regimens used.. Patient serum-induced PLT activation was inhibited in vitro by IVIG in a dose-dependent fashion; inhibition of PLT activation by IVIG was much more marked in the absence of heparin versus the presence of heparin (0.2 U/mL). Our literature review indicated 1 g/kg × 2 IVIG dosing as most common for treating HIT, usually associated with rapid PLT count recovery.. Our clinical and laboratory observations support dose-dependent efficacy of IVIG for decreasing PLT activation and thus correcting thrombocytopenia in aHIT. Our case experience and literature review suggests dosing of 1 g/kg IVIG × 2 for patients with severe aHIT.

Topics: Aged; Aortic Aneurysm; Aortic Dissection; Cardiopulmonary Bypass; Cells, Cultured; Disease Progression; Gangrene; Heparin; Hirudins; Humans; Immunoglobulins, Intravenous; Male; Partial Thromboplastin Time; Peptide Fragments; Purpura, Thrombocytopenic, Idiopathic; Recombinant Proteins; Venous Thrombosis

The use of extracorporeal membrane oxygenation (ECMO) support for cardiac and respiratory failure has increased in recent years. Improvements in ECMO oxygenator and pump technologies have aided this increase in utilization. Additionally, reports of successful outcomes in supporting patients with respiratory failure during the 2009 H1N1 pandemic and reports of ECMO during cardiopulmonary resuscitation have led to increased uptake of ECMO. Patients requiring ECMO are a heterogenous group of critically ill patients with cardiac and respiratory failure. Bleeding and thrombotic complications remain a leading cause of morbidity and mortality in patients on ECMO. In this review, we describe the mechanisms and management of hemostatic, thrombotic and hemolytic complications during ECMO support.

Topics: Anticoagulants; Blood Coagulation; Blood Coagulation Tests; Cardiac Output, Low; Cardiac Tamponade; Extracorporeal Membrane Oxygenation; Hemolysis; Hemorheology; Hemorrhage; Heparin; Hirudins; Humans; Peptide Fragments; Purpura, Thrombocytopenic, Idiopathic; Recombinant Proteins; Respiratory Insufficiency; Thrombosis; von Willebrand Diseases

Heparin-induced thrombocytopenia/thrombosis is an immunologic reaction to unfractionated heparin characterized by thrombocytopenia, platelet activation and thrombosis. A high index of suspicion is required for timely diagnosis and treatment. Treatment is complex and outcome maybe less then satisfactory.

Topics: Ancrod; Antibodies; Anticoagulants; Arginine; Cardiovascular Diseases; Chondroitin Sulfates; Dermatan Sulfate; Fibrinolytic Agents; Heparin; Heparin, Low-Molecular-Weight; Heparitin Sulfate; Hirudin Therapy; Hirudins; Humans; Peptide Fragments; Pipecolic Acids; Practice Guidelines as Topic; Purpura, Thrombocytopenic, Idiopathic; Recombinant Proteins; Sulfonamides; Thrombin

Patients with a previous history of heparin-induced thrombocytopenia are at a higher risk for thromboembolic events, and heparin administration is formally contraindicated. Bivalirudin has been reported as an alternative therapy whenever an intervention that requires systemic anticoagulation and cardiopulmonary by-pass pump is needed. We present the case of a patient diagnosed with heparin-induced thrombocytopenia and heparin-PF4 (+) antibodies requiring a triple cardiac valve replacement who developed fulminant coagulopathy after bivalirudin administration. A discussion on the serious difficulties that the management of these types of patients involves, as well as a review of prevention strategies are presented.

Topics: Acute Kidney Injury; Aged; Anticoagulants; Antithrombins; Blood Loss, Surgical; Coronary Artery Bypass; Disseminated Intravascular Coagulation; Drug Substitution; Fatal Outcome; Heart Failure; Heart Valve Diseases; Heart Valve Prosthesis Implantation; Heparin; Hirudins; Humans; Immunoglobulin G; Intraoperative Complications; Male; Multiple Organ Failure; Peptide Fragments; Platelet Factor 4; Purpura, Thrombocytopenic, Idiopathic; Recombinant Proteins; Thrombophilia