VTE in Cardiology
Cardiovascular disease predisposes patients to VTE. Patients with acute or chronic congestive heart failure (CHF) are a group at known, high risk of VTE. Heart failure is associated with endothelial dysfunction, stasis, and a hypercoagulable state, which all increase thrombotic risk. As CHF worsens, so the risk of VTE increases. Data from a number of case series indicate that in CHF patients have approximately a 3-fold increased risk of DVT (odds ratio between 2.6 and 2.9).1,2 Patients with New York Heart Association (NYHA) class III or IV disease, where left ventricular ejection fraction (LVEF) is < 20%, have been shown to have an adjusted odds ratio for VTE risk of 38.3.1
Given the high risk faced by patients with CHF, there is a strong rationale for using antithrombotic agents in this patient group. Antithrombotic therapy not only helps to prevent VTE, but it can also help prevent systemic embolism, stroke, and coronary thrombosis.
In the MEDENOX study, which assessed LMWH prophylaxis in acutely ill patients, 34.1% of the cohort had acute CHF.3 A post-hoc analysis of this study found that patients with acute HF benefited from LMWH therapy. While the rate of VTE was 14.6% in patients given placebo, this was reduced to 4.0% in the enoxaparin group (40mg qd) (p = 0.02), a 74% relative risk reduction. In patients with class IV HF, there were no cases of VTE among patients given LMWH prophylaxis.4 Both dalteparin and fondaparinux thromboprophylaxis also reduced VTE rate in patients with CHF, as shown by PREVENT and ARTEMIS studies, respectively.5,6
In the THE-PRINCE study, which compared UFH and LMWH (enoxaparin) for VTE prevention in patients with CHF, the rate of VTE events was 16.1% in the UFH group and 9.7% in the LMWH group. Patient numbers were too small for this reduction in VTE events to be statistically significant, but the study clearly demonstrated at least the equivalence of LMWH and UFH.7
Current guidelines on the use of thromboprophylaxis give clear recommendations regarding cardiology patients. The 7th ACCP guidelines give a Grade 1A recommendation, and the International Consensus Statement a Grade A recommendation, that patients admitted to hospital with CHF should receive LMWH or low-dose unfractionated heparin (LDUH). 8,9 This recommendation is in keeping with the guidelines of the Institute for Clinical Systems Improvement (ICSI), which in 2005 declared that there should be an increase in the percentage of hospitalized patients given pharmacological and mechanical prophylaxis unless contraindicated.
- Howell MD, Geraci JM, et al. Congestive heart failure and outpatient risk of venous thromboembolism: a retrospective, case-control study. J Clin Epidemiol. 2001;54:810-6.
- Samama MM. An epidemiologic study of risk factors for deep vein thrombosis in medical outpatients: the Sirius study. Arch Intern Med. 2000;160:3415-20.
- Samama MM, Cohen AT, et al. A comparison of enoxaparin with placebo for the prevention of venous thromboembolism in acutely ill medical patients. Prophylaxis in Medical Patients with Enoxaparin Study Group. N Engl J Med. 1999;341:793-800.
- Alikhan R, Cohen AT, et al. Prevention of venous thromboembolism in medical patients with enoxaparin: a subgroup analysis of the MEDENOX study. Blood Coagul Fibrinolysis. 2003;14:341-6.
- Leizorovicz A, Cohen AT, et al. Randomized, placebo-controlled trial of dalteparin for the prevention of venous thromboembolism in acutely ill medical patients. Circulation. 2004;110:874-9.
- Cohen AT, Davidson BL, et al. Efficacy and safety of fondaparinux for the prevention of venous thromboembolism in older acute medical patients: randomised placebo controlled trial. BMJ. 2006;332:325-9.
- Kleber FX, Witt C, et al. Randomized comparison of enoxaparin with unfractionated heparin for the prevention of venous thromboembolism in medical patients with heart failure or severe respiratory disease. Am Heart J. 2003;145:614-21.
- Geerts WH, Pineo GF, et al. Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004;126(3 Suppl):338-400S.
- Nicolaides AN, Breddin HK, et al. Prevention of venous thromboembolism. International Consensus Statement. Guidelines compiled in accordance with the scientific evidence. Int Angiol. 2001;20:1-37.