Venous Thromboembolism and Acute Coronary Syndrome: Community Pharmacists' Key Position in The Continuum of Care
Robert B. Parker, PharmD*
Despite important advances in the treatment of acute coronary syndrome (ACS) and venous thromboembolism (VTE), these 2 conditions continue to be associated with major morbidity and mortality in the United States each year. VTE, which comprises deep venous thrombosis (DVT) and pulmonary embolism (PE), is estimated to affect approximately 1 to 2 per 1000 people each year, and the risk increases exponentially with age,1 with an estimated annual prevalence of more than 250 000 cases per year.2 More than 33% of these cases are thought to represent recurrent disease3; despite initial management of a first DVT or PE, patients remain at high risk for recurrence, with 7% to 14% of patients experiencing a subsequent DVT or PE. The majority of recurrence is typically noted within 3 months following the incident DVT or PE event.4 VTE also represents a significant financial burden. In a recent retrospective cohort study in 2 large US healthcare plans, the mean total reimbursed costs associated with VTE incidence were $7712 (median: $3131) for a DVT event, rising to $12 200 for a combined DVT and PE event (median: $6678). This study also showed that patients who experienced recurrent DVT, PE, or both incurred an additional mean total healthcare cost of $12 326 per event.5
Acute coronary syndrome is an umbrella term describing a group of symptoms caused by acute myocardial ischemia. ACS is typically caused by atherosclerotic coronary artery disease. Upon presentation, patients with symptoms of ACS are typically classified by the absence or presence of ST-segment elevation on a 12-lead electrocardiogram, as well as abnormal elevations of certain cardiac enzymes. Based on these criteria, patients are classified into 1 of 3 categories—unstable angina (UA), ST-elevation myocardial infarction (STEMI), or non-STEMI (NSTEMI). ACS also represents a significant public health burden. According to the American Heart Association (AHA), preliminary estimates indicate that approximately 1.6 million patients were hospitalized for ACS in 2004, including 896 000 patients diagnosed with myocardial infarction (MI) and 669 000 with UA. Approximately 21 000 of these patients were discharged with both diagnoses.6 For patients experiencing ACS, UA/NSTEMI occurs more frequently, with only 30% to 45% of patients with MI having STEMI.7 ACS also exacts a high toll in terms of direct treatment-related and management costs, as well as indirect social and economic costs.8,9 Direct US costs in 2007 for coronary heart disease (CHD)—most of which consist of costs for ACS, physician, and other professional costs—are estimated at $83.6 billion. These include hospital costs ($48.4 billion), nursing home costs ($11.6 billion), the cost of drugs and other medical durables ($9.2 billion), physicians/other professionals ($12.5 billion), and home healthcare at $1.9 billion.10 Indirect US costs of CHD for 2007 (because of lost productivity) are estimated to be $68 billion.10
Because thrombosis is the underlying mechanism for both ACS and VTE, antithrombotic therapy represents a key component of treatment and prophylaxis for both conditions. For many years, treatment options were limited to unfractionated heparin and warfarin. However, over the past 15 years, newer agents have emerged that make the choice of an appropriate agent more complex. Therapeutic options now include low molecular weight heparins, direct thrombin inhibitors, and indirect inhibitors of factor Xa.
In this issue of University of Tennessee Advanced Studies in Pharmacy, William E. Dager, PharmD, begins with a review of the 3 components of ACS—UA, NSTEMI, or STEMI. He discusses risk stratification, pathophysiology, and updates to the American College of Cardiology/AHA treatment guidelines for UA/STEMI and NSTEMI. Edith A. Nutescu, PharmD, then explains the epidemiology, risk factors, and pathophysiology of DVT and PE, along with the criteria used to confirm the diagnosis of VTE. She also reviews the economic impact of VTE and outlines the current and emerging pharmacologic strategies, in addition to the American College of Chest Physician guidelines for treatment and prophylaxis of VTE. Next, James Groce, PharmD, CACP, reviews anticoagulation strategies in the community setting. His article covers established pharmacologic strategies for the management of prophylaxis and treatment of VTE and ACS; the risks, benefits, and therapeutic drawbacks of older and newer agents; and compares the efficacy and safety data of various agents for use in the prevention of both conditions. In addition, Dr Groce addresses issues relative to whether newer agents are likely to be more cost effective throughout the continuum of care.
This monograph also includes case studies presented by Dr Dager and Dr Nutescu. In his case, Dr Dager emphasizes the important role the community pharmacist plays in reinforcing the importance of medication adherence in order to maximize patient outcomes and quality of life. Dr Nutescu follows with a case study that illustrates the complexities of managing VTE in a patient undergoing hip replacement surgery.
This issue of University of Tennessee Advanced Studies in Pharmacy provides pharmacists with an update on the cornerstones of current antithrombotic strategies, most recent practice guidelines for VTE and ACS, and focuses on the importance of early diagnosis and prolonged prophylaxis. After completing this monograph, readers should be better equipped to help their patients with thromboembolic disorders achieve improved clinical survival and long-term functional benefit.
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5. Bullano MF, Willey V, Hauch O, et al. Longitudinal evaluation of health plan cost per venous thromboembolism or bleed event in patients with a prior venous thromboembolism event during hospitalization. J Manag Care Pharm. 2005;11:663-673.
6. Rosamond W, Flegal K, Friday G, et al. Heart disease and stroke statistics–2007 update. A report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation. 2007;115:e69-e171.
7. Viviott SD, Morrow DA, Giugliano RP, et al. Performance of the thrombolysis in myocardial infarction risk index for early acute coronary syndrome in the National Registry of Myocardial Infarction: a simple risk index predicts mortality in both ST and non-ST elevation myocardial infarction. J Am Coll Cardiol. 2003;41:365A-366A.
8. Kauf TL, Velazquez EJ, Crosslin DR, et al. The cost of acute myocardial infarction in the new millennium: evidence from a multinational registry. Am Heart J. 2006;151:206-212.
9. Turpie A. Burden of disease: medical and economic impact of acute coronary syndromes. Am J Manag Care. 2006; 12:S430-S434.
10. American Heart Association and American Stroke Association. Heart Disease and Stroke Statistics–2007 Update At-a-Glance. Available at: http://www.americanheart.org/downloadable/heart/1166712318459HS_StatsInsideText.pdf. Accessed September 20, 2007.
*Professor, University of Tennessee College of Pharmacy, Department of Clinical Pharmacy, Memphis, Tennessee.
Address correspondence to: Robert B. Parker, PharmD, Professor, University of Tennessee, Department of Clinical Pharmacy, 26 South Dunlap Street, Memphis, TN 38163. E-mail: firstname.lastname@example.org.