Fletcher Factor Deficiency in Cardiac Anesthesia A Case Report

摘要

Introduction Fletcher-factor deficiency (Fletcher-trait) was first described by Hathaway et al. in 1965 1. The asymptomatic clotting defect is characterized by a prolonged partial thromboplastin time APTT, normal prothrombin time PT and bleeding time. In 1973 and 1974 other authors identified Fletcher-factor as plasma prekallikrein 23. The coagulation disorder is considered as very rare and as clinically non-significant 4. We describe for the first time the management of anticoagulation in a patient with Fletcher-factor deficiency undergoing cardiopulmonary bypass for coronary artery bypass graft surgery. Case Report A 64-year-old white woman was admitted to the hospital with severe retrosternal pain with radiation to the neck and left shoulder. In her medical history she was known to have hypertension and coronary artery disease with myocardial infarction. In addition, the patient had a history of peptic ulcer disease, GI bleeding, transient ischemic attack and mild stroke in the past. The cardiac enzymes did not show evidence of acute myocardial infarction. The patient was diagnosed with severe coronary artery disease, hypertension, progressive angina pectoris and abdominal aortic aneurysm. Left heart catheterization showed a 70 -80% stenosis of the mid-portion of the left anterior descending (LAD), a 70% stenosis of the obtuse marginal (OM) and a 80% stenosis of the proximal circumflex coronary artery (RCX). Ejection fraction (EF) measured by cardiac echocardiography was 35 - 40%. There was a global left-ventricular hypokinesis. The patient was scheduled for coronary artery bypass graft surgery.During the preanesthetic evaluation she disclosed that she had a Fletcher-factor deficiency. Prothrombin time (PT = 11.3 sec.) and partial thromboplastin time (APTT = 27 sec.) were normal. She denied having a clinically significant bleeding disorder. It was decided that heparinization for cardiopulmonary bypass should be monitored with the protamine-titration-test (Hepcon HMS, Medtronic, Hemotec Inc) rather than be guided by the routinely used activated clotting time (ACT). We did not know what impact the Fletcher-factor deficiency may have on ACT’s, therefore we preferred direct heparin measurements.After induction of anesthesia a blood sample was taken for baseline heparin level and ACT. The celite-based ACT (Hemochron 801, International Technidyne Corporation, Edison, NJ) showed a baseline ACT of 320 sec., the Hepcon-test a baseline heparin level of 0 mg/kg and the kaolin-based ACT a baseline ACT of 449 sec. Subsequently the patient was heparinized with 240 mg (4 mg/kg) porcine heparin prior to connection to the cardiopulmonary bypass. Thereafter a heparin level of 3 mg/kg, a celite-based ACT of 648 sec. and a kaolin-based ACT of >1000 sec. were measured. Another 50 mg heparin were added to the cardiopulmonary bypass machine (CPB). The surgeon found on exposure an ascending aortic aneurysm which ruptured slightly during administration of the cardioplegic solution after aortic cross-clamping. He decided to replace the proximal portion of the ascending aorta. 30 minutes later we obtained a heparin level of 3 mg/kg and a kaolin-based ACT of >1000 sec. Celite-based ACT was not measured at this time. Additional 50 mg heparin were added to the CPB. After the next 30 minutes the heparin level was 2.5 mg/kg, the celite ACT 528 sec. and the kaolin ACT >1000 sec. Additional 50 mg heparin were added to the CPB. After another 25 minutes the heparin level was 2.5 mg/kg and the kaolin ACT >1000 sec. Celite-based ACT was not measured at this time. During the surgery 3 vessel coronary artery bypass graft and ascending aorta repair was performed. The patient was then separated from the CPB. Heparin reversal was accomplished with 240 mg of protamine. The patient received a transfusion of 3 singles units of fresh frozen plasma FFP and 10 units of platelets. 5 minutes after completion of the protamine infusion a heparin level of 0 mg/kg was obtained.