Patient Care Hematology & Oncology - October 2007 - (Page 10)

I Bridge anticoagulation TABLE 1 Conditions that place patients at high risk for thromboembolic events Arterial indications Venous indications AF and previous thromboembolism AF and valvular heart disease Mechanical heart valve in mitral position Mechanical heart valve in aortic position with severe LV dysfunction Mechanical heart valve and previous thromboembolic event Caged-ball type prosthetic heart valve Acute peripheral thromboembolic event within 1 mo Key: AF, atrial fibrillation; LV, left ventricular; VTE, venous thromboembolism. Active malignancy Multiple episodes of VTE Acute thromboembolism within 1 mo (deep venous thrombosis or pulmonary embolism) Known thrombophilic states with single defect (protein C and S deficiencies, prothrombin gene mutation, systemic lupus erythematosus with cardiolipin antibodies, antithrombin deficiency, homozygous factor V Leiden, antiphospholipid antibody syndrome) or combined defects Source: Dunn AS, Turpie AG. Perioperative management of patients receiving oral anticoagulation: a systematic review. Arch Intern Med. 2003;163: 901-908. tal confinement from start to finish. The CBC and platelet counts should also be monitored for timely identification of the not uncommon UFH complication of heparin-induced thrombocytopenia (HIT).6 Although the use of LMWH for bridge therapy has become increasingly popular over the last decade, there are no randomized controlled trials that assess the optimal dosage regimens or timing of conversion to or from LMWH. LMWHs offer several advantages over UFH. Their longer half-life allows for once- or twice-daily SC administration. Their superior bioavailability and reduced protein binding result in a more predictable dose response and obviate the need for laboratory monitoring of the aPTT. In addition, LMWHs as a group are much less likely to cause HIT and osteopenia. The 3 LMWHs available in the United States are dalteparin (Fragmin), enoxaparin (Lovenox), and tinzaparin (Innohep). Approximately 2 decades of extensive clinical research have established the efficacy and safety of LMWH in the prevention and treatment of thromboembolic events. Limitations to its use for bridge anticoagulation therapy include the relative dearth of experience with it compared to UFH for this purpose, its lack of reversibility, and a relative contraindication for its use in those with renal impairment. Studies of LMWH in the periprocedural period have been largely observational. Collectively, the 11 studies evaluated included 1350 high-risk patients undergoing bridge therapy with one of the LMWHs.3,4 The indications for OAC and periprocedural bridging included AF mechanical heart , valves, thrombophilia, and documented hypercoagulable states, including protein C deficiency, protein S deficiency, and antiphospholipid antibody syndrome. Most of these studies employed therapeutic doses of LMWH before and after surgery, in some cases on an outpatient basis. Bleeding and thromboembolic events were comparable to rates seen with UFH. Accordingly, it was concluded that LMWHs are safe and effective anticoagulants in the perioperative period and that they can be used as an alternative to UFH. One of the largest observational studies of LMWH in the periprocedural period evaluated the 10 PATIENT CARE HEMATOLOGY & ONCOLOGY www.patientcareonline.com http://www.patientcareonline.com

Table of Contents Feed for the Digital Edition of Patient Care Hematology & Oncology - October 2007

Patient Care - Hematology & Oncology - October 2007 Research Digest Contents Information for Authors Medicine in the News Strategies for Bridge Anticoagulation Therapy How to Integrate the New Cervical Cancer Guidelines into Practice Dermatology Case Challenge Clinical Clips Classified Advertising

Patient Care Hematology & Oncology - October 2007

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.