bivalirudin and Aortic-Aneurysm

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

A 74-year-old female had urgent surgery with replacement of the ascending aorta for acute type A dissection. Postprocedure, the electrocardiogram showed an ST-segment elevation myocardial infarction in the antero-lateral leads. Angiography revealed a thrombotic occlusion of the left anterior descending artery, treated successfully with bivalirudin administration, thrombus aspiration and a balloon angioplasty. This case involves the rare coexistence of acute type A aortic dissection and myocardial infarction due to coronary plaque thrombosis.

Topics: Acute Disease; Aged; Angioplasty, Balloon, Coronary; Aorta; Aortic Aneurysm; Aortic Dissection; Coronary Angiography; Coronary Vessels; Electrocardiography; Female; Hirudins; Humans; Myocardial Infarction; Peptide Fragments; Recombinant Proteins; Thrombectomy; Thrombosis; Treatment Outcome

Heparin-induced thrombocytopenia is a well-recognized complication of anticoagulation with heparin. We present the case of a patient with recent heparin-induced thrombocytopenia who subsequently needed surgery on an emergency basis for acute type A aortic dissection. This article reports the successful use of bivalirudin, a direct thrombin inhibitor, as an alternative to heparin throughout cardiopulmonary bypass and deep hypothermic circulatory arrest. We contend that bivalirudin is a safe alternative to heparin when performing surgery for aortic dissection and should be considered as an option for use in patients who present with heparin-induced thrombocytopenia.

Topics: Aged, 80 and over; Anticoagulants; Aortic Aneurysm; Aortic Dissection; Blood Vessel Prosthesis Implantation; Cardiopulmonary Bypass; Circulatory Arrest, Deep Hypothermia Induced; Contraindications; Drug Administration Schedule; Emergencies; Heparin; Hirudins; Humans; Male; Peptide Fragments; Recombinant Proteins; Risk Factors; Thrombocytopenia; Treatment Outcome

A patient with myocardial failure after repair of an acute type A aortic dissection had acute heparin-induced thrombocytopenia develop during extracorporeal membrane oxygenation. Heparin was discontinued and the anticoagulant was switched to the direct thrombin inhibitor bivalirudin given with a bolus of 0.5 mg/kg followed by a continuous infusion of 0.5 mg/kg/h. Using this protocol, activated clotting time values ranged from 200 to 220 seconds. After prolonged extracorporeal membrane oxygenation support and recovery of left ventricular function, a right ventricular assist device was implanted during extracorporeal membrane oxygenation support with bivalirudin anticoagulation. For this procedure an additional bolus of 0.25 mg/kg bivalirudin was given, and the infusion rate increased to 1 mg/kg/h to achieve activated clotting time values of 300 to 350 seconds. Surgery was successfully performed with moderate intraoperative and postoperative blood loss and transfusion requirements.

Topics: Adult; Anticoagulants; Aortic Aneurysm; Aortic Dissection; Cardiac Surgical Procedures; Extracorporeal Membrane Oxygenation; Female; Heart Failure; Heart-Assist Devices; Heparin; Hirudins; Humans; Peptide Fragments; Recombinant Proteins; Thrombocytopenia