Pharmacy & Therapeutics - February 2008 - (Page 107)

Evaluation of the Management of Acute Venous Thromboembolism and Its Outcomes One Institution’s Experience Cristin Williams, PharmD, Ji Koo, PharmD, and Jonathan Hass, PharmD ABSTRACT Background: There is often a divergence between standardized practice guidelines and actual practice. Such deviations can result in adverse outcomes. In addition, studies that identify independent risk factors associated with bleeding or recurrent venous thromboembolism (VTE) are often limited. Objective: We sought to evaluate the appropriateness of VTE management at our Veterans Affairs facility in Fargo and to identify independent patient characteristics or treatments that were associated with recurrence of VTE or major bleeding. Methods: We performed a retrospective chart review of patients admitted for deep vein thrombosis (DVT) and/or pulmonary embolism (PE). Results: Of the patients who were given enoxaparin, 96% received an appropriate dose; however, of the patients receiving unfractionated heparin, only 54.7% received an appropriate initial dose. The International Normalized Ratio (INR) was below 1.9 in 19.3% of patients when heparin was stopped, unknown in 12.7%, and 1.9 or higher in 68%. Thirty-two patients (21.3%) continued to take warfarin for three months or less, and 13 of these patients (41%) were treated for an idiopathic VTE. Forty-eight patients (57%) being treated for VTE for the first time continued with warfarin for more than six months. Twenty-one patients (14%) were started on 10 mg of warfarin daily; 40% received heparin for less than five days. The only significant difference between the bleeding and non-bleeding groups was an INR above 3 at the time of the bleeding episode (P < 0.0001). Conclusion: We learned that the management of VTE at our institution diverged from standardized practice guidelines. Larger randomized, prospective studies are needed to identify independent risk factors for major bleeding or recurrence of VTE and their correlation with patient outcomes. as 36.4%.1 In 2005, a retrospective cohort study by Caprini et al. suggested that there was a difference between actual practice and international treatment guidelines for acute VTE.2 For the initial management of DVT, the 2004 American College of Chest Physicians (ACCP) guidelines recommended that low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) be continued for at least five days and that heparin be discontinued only when the patient’s INR was stable and higher than 2.3 The goal INR for the treatment of VTE is 2 to 3. The duration of therapy with warfarin (Coumadin, Bristol-Myers Squibb) depends on whether the patient has a history of VTE or other pre-existing risk factors for VTE. Because bleeding is a significant risk factor when anticoagulation therapy begins, patients must be adequately monitored for signs and symptoms of bleeding. At a minimum, laboratory monitoring should include the INR, hemoglobin and platelet counts, and an activated partial thromboplastin time if the patient is receiving therapeutic doses of UFH. Bleeding events are generally considered major if they are associated with a decrease in hemoglobin of at least 2 g/dL, if the patient needs a transfusion of 2 or more units of red blood cells, or if a critical site (i.e., the retroperitoneal cavity or intracranial space) is affected.4 Previous research had indicated that standardized guidelines for treating VTE were not being followed in actual clinical practice; whether that held true for our Veterans Affairs (VA) facility in Fargo was unclear. Therefore, our primary objective was to evaluate the appropriateness of VTE management at our center in an attempt to determine whether standardized recommendations were being followed. Our secondar y objective was to identify differences in patient characteristics or treatment strategies that might have contributed to recurrence of VTE or bleeding events. INTRODUCTION Patients with venous thromboembolism (VTE), which includes deep vein thrombosis (DVT), pulmonary embolism (PE), or a combination of both, need proper initial and followup management in order to reduce the risk of serious complications (i.e., recurrence, major bleeding, and death). The death rate in the first year after an acute VTE can be as high Dr. Williams is a Pharmacy Practice Resident, Dr. Koo is a Clinical Pharmacy Coordinator and Adjunctive Assistant Professor of Pharmacy Practice, and Dr. Hass is a Clinical Pharmacy Specialist, all at the Veterans Affairs Medical Center in Fargo, North Dakota. METHODS We conducted a retrospective review of all charts from a computer-generated list of patients who were admitted to the VA Medical Center in Fargo with DVT or PE between January 1, 1998, and December 31, 2005. Diagnostic codes were based on criteria from the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Patients were excluded from the study if they were already using warfarin at the time of admission, but they were not excluded if they had previously been treated for an acute VTE and were not using warfarin at the time of admission for the current VTE. Patients were also excluded if they were not manDisclosure: The authors have no commercial or financial relationships to disclose in regard to this article. Accepted for publication December 10, 2007. Vol. 33 No. 2 • February 2008 • P&T® 107

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Pharmacy & Therapeutics - February 2008 Contents Editorial Medication Errors Prescription: Washington The Language of (Forgive Us) Change, As P&T Enters the Digital Age New Drugs/Drug News/New Medical Devices Drug Forecast Use and Outcomes of Antifibrinolytic Therapy in Patients Undergoing Cardiothoracic Surgery at 20 Academic Medical Centers in the United States Evaluation of the Management of Acute Venous Thromboembolism and Its Outcomes: One Institution's Experience American Society of Hematology, 49th Annual Meeting Pharmaceutical Approval Update

Pharmacy & Therapeutics - February 2008

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