Prolonged acenocoumarol treatment in patients with venous thromboembolic disease from a rural area.

To the Editor: The recent American College of Chest Physicians conference has recommended more prolonged periods of anticoagulant treatment in patients with venous thromboembolic disease (VTD). (1) For example, it has suggested that patients with a first episode of idiopathic VTD be considered for indefinite anticoagulant treatment. (1) However, the incidence of major hemorrhage is higher in the clinical practice than in clinical trials. (2,3) We studied the outcomes in patients treated with acenocoumarol for more than 6 months in a series of consecutive outpatients with VTD from a rural Spanish area.

We conducted a prospective observational study of 94 consecutive outpatients diagnosed in a first-level hospital from a rural area of Extremadura (Spain) with venous thromboembolic disease (VTD), deep vein thrombosis and/or pulmonary embolism. All patients were treated with low molecular weight heparin in the acute phase. As long-term treatment, 35 patients received acenocoumarol for more than 6 months, according to the attendant physician's criterion. Twenty patients (57.1%) had "idiopathic" VTD (nonassociated with "classical" risk factors: recent surgery, immobilization and/or cancer). Sixteen patients (45.7%) had pulmonary thromboembolism, 13 (37.1%) proximal isolated deep vein thrombosis and 6 (17.1%) distal isolated deep vein thrombosis. The other characteristics of patients are shown in the Table. The median follow-up was 12.7 months (range 8-29 mo). No patient died and no patient had thromboembolic recurrence. One patient (2.8%) had a major hemorrhage (gastrointestinal hemorrhage after 14 months of acenocoumarol treatment).

The annual incidence of major hemorrhage associated with anticoagulant treatment in patients with VTD in clinical trials is usually lower than 4%. (2) In the clinical practice, this incidence may be higher. For example, an observational study of patients treated with oral anticoagulants because of diverse indications reported an incidence of major hemorrhage (7%) in the first year. (3) Therefore, the recent recommendation of more prolonged anticoagulant treatments in patients with VTD (1) might not be applicable in the clinical practice.

In our study of outpatients with VTD treated with acenocoumarol for more than 6 months, there was no death and no thromboembolic recurrence and the frequency of major hemorrhage was about 3% after a mean follow-up of almost 13 months. We point out that most patients were elderly, and major hemorrhages associated with anticoagulant treatment may be more frequent in the elderly. (2) However, other risk factors for hemorrhage associated with anticoagulant treatment, such as cancer and chronic renal failure, (2,3) were infrequent in our study. Prolonging treatment for VTD with acenocoumarol for more than 6 months may be useful in outpatients with characteristics similar to the patients of this study. However, further studies in the clinical practice with a higher number of patients and other characteristics are necessary to confirm and to extend this recommendation.

Jose Maria Calvo-Romero, MD

Internal Medicine Service

Hospital Ciudad de Coria, Coria (Caceres)

Spain

Esther Maria Lima-Rodriguez, MD

Family Medicine

Area de Salud de Coria (Caceres)

Spain

References

1. Buller HR, Agnelli G, Hull RD, et al. Antithrombotic therapy for venous thromboembolic disease: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004;126(3 Suppl):401S-428S.

2. Levine MN, Raskob G, Beyth RJ, et al. Hemorrhagic complications of anticoagulant treatment: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004;126(3 Suppl):287S-310S.

3. McMahan DA, Smith DM, Carey MA, et al. Risk of major hemorrhage for outpatients treated with warfarin. J Gen Intern Med 1998; 13:311-316.

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Table. Characteristics of study patients (n = 35)

Age (mean, years)                72.7

Age (range, years)               46-88
Age >70 years                    25 (71.4%)
Sex male                         19 (54.3%)
Cancer                            3 (8.6%)
Chronic cardiopulmonary disease  10 (28.6%)
Chronic renal failure*            3 (8.6%)
Previous VTD                      4 (11.4%)

*Serum creatinine >1.5 mg/dL. VTD: venous thromboembolic disease.