Anti-Xa assays: their role in managing un-fractioned heparin therapy in special population

Abstract

Anca Tau, Andreea Rachieru, Alina Ganta and Catalin Copaescu

Assessing and managing the risk of bleeding in a preoperative patient can be achieved by a multidisciplinary approach. Risk factors that increase the likelihood of perioperative bleeding may include the patient�??s underlying health problems as well as factors associated with each specific type of surgery. The benefits of stroke prevention still outweigh the risks of bleeding in most patients with AF. By combining risk scores for patient co-morbidity and the complexity of surgery, we can stratify overall risk and determine which patients should undergo more extensive preoperative evaluation and close monitoring of antithrombotic therapy. The anti - Xa assay is designed to measure plasma heparin (UH and LMWH) levels and to monitor anticoagulant therapy. Most patients receiving LMWH do not need anticoagulation monitoring . If LMWH is administered to patients with renal dysfunction, those at the extremes of weight, infants, pregnant women, or patients at high risk for thrombosis/bleeding, the anti-Xa assay plays an essential role, since it is the only assay offered for this purpose ( LMWH has minimal effect on PTT). We assessed 98 patients, critically ill patients and special populations receiving LMWH �?? with morbid obesity undergoing bariatric surgery, renal disease, suspected heparin resistance, etc. The primary end point of the study was to evaluate the correlation between the prophylactic or therapeutic doses of LMWH and anti X-a assay. Secondary end points, including major bleeding and thrombotic events, were evaluated for the duration of hospitalization. For all bleeding and thrombotic events, we also evaluated aPTT and anti-X a values during the treatment period with LMWH. In conclusion, in patients at a significantly increased risk of major bleeding events, we outline the importance of anti-X a assay. Our aim is to guide clinical management of LMWH to determine whether discordance in laboratory values was associated with adverse clinical outcomes.

PDF