Practical approach to anticoagulation for cardiopulmonary bypass in the patient with congenital prolonged activated partial thromboplastin time
Department of Anesthesiology, The University of Alabama at Birmingham, 901 19th Street South, Birmingham, AL 35294, USA.Blood Coagulation and Fibrinolysis (Impact Factor: 1.4). 11/2008; 19(7):725-6. DOI: 10.1097/MBC.0b013e32830891ab
Patients with rare, congenital deficiencies of contact proteins (e.g., factor XII, prekallikrein, high-molecular-weight kininogen) present an important challenge with regard to safe anticoagulation during cardiopulmonary bypass. Specifically, activated coagulation time values are obtained with devices that utilize contact protein activators to generate thrombin and assess the efficacy of heparin-mediated antithrombin activation, with an activated coagulation time value of 480 s considered 'safe'. Patients with contact protein deficiencies will routinely have activated coagulation time values that exceed normal baseline values to an unpredictable extent, which, when coupled with heparin administration may well exceed 480 s but still potentially not reflect adequate antithrombin activation. We present the successful management of anticoagulation of a patient with either a prekallikrein or kininogen deficiency during cardiopulmonary bypass for coronary artery bypass graft surgery with Hepcon-based heparin concentration determinations. This approach, and the other alternatives previously mentioned, can be utilized to safely care for these rare patients in the setting of cardiac surgery.
- [Show abstract] [Hide abstract]
ABSTRACT: Prekallikrein is 1 of the factors involved in the contact phase of coagulation, and prekallikrein deficiency is characterized with no spontaneous or injury-related bleeding, despite markedly prolonged activated partial thromboplastin time (aPTT). The literature on the management of these patients during preoperative evaluation and delivery to surgery is limited, Herein we present a prekallikrein deficient 14-month-old boy who experienced no bleeding during or after epilepsy surgery with 1 course of fresh frozen plasma prior to surgery.Laboratory Medicine 04/2010; 41(5):271-274. DOI:10.1309/LM5VS8FIFRF1OHCT · 0.51 Impact Factor
Article: Congenital prekallikrein deficiency[Show abstract] [Hide abstract]
ABSTRACT: The congenital deficiency of prekallikrein (PK) is a rare condition in which there is a peculiar discrepancy between a severe in vitro defect and absence of bleeding. The gene controlling PK synthesis is located on chromosome 4 and consists of 14 exons and 15 introns. Only approximately 80 cases of PK deficiency have been described in the literature. Owing to the lack of bleeding, most cases go undetected or, if detected, go unreported. Occasional bleeding or thrombosis have been reported in a few patients but this was only due to the presence of associated risk factors. It is certain that the defect does not protect from thrombosis. Diagnosis is based on the presence of a great prolongation of partial thromboplastin time and normal prothrombin time and thrombin time. The long partial thromboplastin time is fully corrected by the addition of normal plasma or normal serum and presents the unusual feature of shortening on long incubation times. Platelet and vascular tests are normal. Immunological studies allow differentiation into two types, namely cases of true deficiency, which are approximately 70% of the total, and cases with abnormal forms. PK is a glycoprotein synthesized in the liver as a single-chain peptide of 88000 Da. It mostly circulates (∼75%) as a complex with high-molecular-weight kininogen. It is cleaved by FXIIa into a heavy chain and a light chain (catalytic domain), held together by disulfide bonds. Molecular biology techniques have so far only been applied to eleven families, and these studies do not yet allow definite phenotype/genotype conclusions. The exons involved are 5, 8, 11, 14 and 15. The noncoagulative effects of PK, mainly based on the effect of kallikrein, have been studied less, since they appear to be the result of the involvement of other components of the contact phase. Kallikrein can mainly affect the formation of bradykinin from high-molecular-weight kininogen and the activation of pro-urokinase to urokinase. Bradykinin causes inflammation, vasodilatation and an increase in vessel permeability. The activation of pro-urokinase results in enhanced fibrinolysis. However, fibrinolysis has been reported to be normal or defective in these patients.Expert Review of Hematology 12/2010; 3(6):685-95. DOI:10.1586/ehm.10.69 · 2.07 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Factor XII deficiency is a laboratory finding in patients who normally do not present with bleeding tendencies. This deficiency is important in the patient undergoing cardiopulmonary bypass because activated clotting times are not helpful in determining proper levels of heparin anticoagulation and its reversal. We present a case of a patient with factor XII deficiency that had coronary artery bypass grafting and cardiopulmonary bypass using heparin for anticoagulation. Cardiopulmonary bypass was successfully carried out by monitoring heparin concentration ensuring adequate heparinization during the procedure. Results from activated clotting time, heparin dose-response, and heparin protamine titration are given. Heparin anticoagulation in patients with factor XII deficiency can be safely carried out with heparin concentration monitoring.The Journal of extra-corporeal technology 09/2015; 46(3):254-7.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.