OBJECTIVE: To determine whether the success and complication rates of oral
anticoagulation obtained in large, well controlled trials, upon which recom
mendations are based, are comparable with routine cardiology practice.
DESIGN: An observational, prospective cohort study collected data on all pa
tients followed at an anticoagulant clinic over one calendar year.
PATIENTS: One thousand and seventy-eight patients anticoagulated for cardio
vascular indications, mainly atrial fibrillation, prosthetic valves and ven
tricular 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 even
ts according to severity. International normalized ratios (INR) were compar
ed 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 hemo
rrhages, defined as those requiring treatment or hospital observation for m
ore 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). T
wenty-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 c
ausing two deaths (0.25% p-y). INRs were within target range 62.3% of the t
ime, with 2.2% of values recorded above 5 and 0.3% above 10.
CONCLUSION: The low failure and complication rates obtained in large, contr
olled trials are similar to those observed in actual cardiology practice.