Oral anticoagulant therapy for heart disease: results in actual cardiology practice.

OBJECTIVE

To determine whether the success and complication rates of oral anticoagulation obtained in large, well controlled trials, upon which recommendations are based, are comparable with routine cardiology practice.

DESIGN

An observational, prospective cohort study collected data on all patients followed at an anticoagulant clinic over one calendar year.

PATIENTS

One thousand and seventy-eight patients anticoagulated for cardiovascular indications, mainly atrial fibrillation, prosthetic valves and ventricular dysfunction, were followed for 804 patient-years of treatment. No patient was lost to follow-up.

INTERVENTIONS

Telephone conversations and regular verification of medical files were used to record and classify all bleeding and thromboembolic events according to severity. International normalized ratios (INR) were compared with target ranges.

RESULTS

One hundred and twelve bleeding events, ie, 13.9/100 patient-years (% p-y), were recorded, of which 61 required medical attention. Major hemorrhages, defined as those requiring treatment or hospital observation for more than 24 h, occurred in 15 instances (1.9% p-y). Among these, 9 (1.1% p-y) were classified as life threatening, with four being fatal (0,5% p-y). Twenty-two thromboembolic events (2.7% p-y) occurred, of which 10 were major (1.2% p-y), leaving three patients (0.4% p-y) with long term sequelae and causing two deaths (0.25% p-y). INRs were within target range 62.3% of the time, with 2.2% of values recorded above 5 and 0.3% above 10.

CONCLUSION

The low failure and complication rates obtained in large, controlled trials are similar to those observed in actual cardiology practice.