hirudin 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

Heparin-induced thrombocytopenia with thrombosis (HITT) is a rare complication of cardiac surgery with cardiopulmonary bypass. We report two cases of HITT treated with the direct thrombin inhibitor Lepirudin. Immediate diagnosis was essential to prompt heparin discontinuation and successful early Lepirudin administration in the first case. In the second, the presence of an intra-aortic balloon pump delayed HITT recognition, and Lepirudin infusion could not prevent limb amputation. In both cases HITT occurred earlier (< 5 days after heparin exposure) than its usual presentation.

Topics: Adult; Aged; Amputation, Surgical; Anticoagulants; Aorta; Aortic Aneurysm; Aortic Dissection; Aortic Valve; Blood Vessel Prosthesis Implantation; Combined Modality Therapy; Coronary Artery Bypass; Early Diagnosis; Fibrinolytic Agents; Heart Valve Prosthesis Implantation; Heparin; Hirudins; Humans; Intra-Aortic Balloon Pumping; Ischemia; Leg; Male; Marfan Syndrome; Mitral Valve; Postoperative Complications; Recombinant Proteins; Thrombocytopenia; Thrombophlebitis