[Identification of factors responsible for oral over-anticoagulation in outpatients with heart disease].
BACKGROUND
Few studies have attempted to investigate the clinical course or identify factors responsible for excessive anticoagulation in patients with heart disease.


OBJECTIVE
To determine the incidence of excessive anticoagulation in outpatients with heart disease treated with acenocoumarol, analyze the factors related with over-anticoagulation, and identify bleeding complications.


METHODS
This 7-month prospective observational study included consecutive outpatients anticoagulated with acenocoumarol. They were seen in an anticoagulation unit. The high INR group of 55 over-anticoagulated patients had at least one test with INR > 5. The control group of 49 patients had INR results strictly within therapeutic range.


RESULTS
A total of 3,683 INR determinations were made in 512 patients. Seventy-seven tests had an INR > 5 (a 2% overall incidence of high-INR). In the group of 55 INR < 5 patients, 31% had more than one INR determination > 5 during follow-up. Multivariate analysis identified four variables as independent predictors of over-anticoagulation: artificial heart valve, poor treatment compliance, addition of potentially interactive new drugs, and illness in the last month. The high-INR group patients had more bleeding episodes (21.8 vs 4.08%; p = 0.008), one of which was major.


CONCLUSIONS
The incidence of excessive oral anticoagulation in our outpatient population was similar to that reported in other studies. Patients with INR > 5 had more total bleeding complications, mostly minor. It is recommended to proceed carefully with oral anticoagulant therapy in patients with an artificial heart valve, suspected poor treatment compliance, addition of potentially interactive new drugs, and illness in the last month.
Freixa
Román
R
Servicio de Cardiología, Hospital Creu Roja, Barcelona, Spain. roman.freixa@consorcicreuroja.es
Blanch
Pedro
P
Ibernón
Montse
M
Padró
Jaume
J
Delso
Javier
J
Sobrepera
José Luis
JL
Salas
Elena
E
Dos
Laura
L
Codinach
Pere
P
D000074:Acenocoumarol / Q000009:adverse effects*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects*; D004363:Drug Utilization / Q000706:statistics & numerical data*; D006331:Heart Diseases / Q000188:drug therapy*; D006470:Hemorrhage / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D019934:International Normalized Ratio; D008875:Middle Aged; D010045:Outpatients; D011446:Prospective Studies; D012307:Risk Factors
D000925:Anticoagulants; D000074:Acenocoumarol