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Bleeding risk factors in chronic oral anticoagulation with acenocoumarol
P Casais1, A Sánchez Luceros, S Meschengieser
1Departamento de Hemostasia y Trombosis, Instituto de Investigaciones Hematológicas "Mariano R. Castex," Academia Nacional de Medicina de Buenos Aires, Argentina.
Insights
Acenocoumarol therapy increases bleeding risk, especially with higher INR targets and variability. Monitoring INR fluctuations and underlying conditions is crucial for patient safety in anticoagulant treatment.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Medicine
Background:
- Acenocoumarol is a widely used oral anticoagulant.
- Bleeding complications are a significant concern in patients receiving anticoagulant therapy.
- Identifying risk factors for hemorrhage is essential for improving patient outcomes.
Purpose of the Study:
- To investigate major bleeding complications and fatal hemorrhages in outpatients treated with acenocoumarol.
- To identify predisposing factors for bleeding events during acenocoumarol therapy.
Main Methods:
- Retrospective analysis of 811 outpatients at an anticoagulant therapy unit.
- Evaluation of intended and achieved International Normalized Ratio (INR) ranges, INR variability, and patient demographics.
- Calculation of major and fatal hemorrhage rates per 100 patient-years.
Main Results:
- 47 major bleeding episodes (2 fatal) occurred in 37 patients over 1,963.26 years of follow-up.
- Higher rates of hemorrhage were observed in patients with a higher intended INR range (3.5-4.5 vs. 2.0-3.0).
- Increased risk of major bleeding was associated with achieved INR > 6 and higher INR variability.
Conclusions:
- The intensity of anticoagulation and INR deviation from target are key risk factors for bleeding.
- Monitoring INR variability can help identify patients predisposed to bleeding.
- Screening for underlying diseases remains important in managing bleeding risk.
Abstract:
We studied major bleeding complications, death related to hemorrhage, and tried to identify predisposing factors for bleeding in outpatients treated with acenocoumarol. We evaluated 811 outpatients attending a specialized anticoagulant therapy unit. The intended INR range was 3.5-4.5 for mechanical heart valve replacement (N= 384) and 2.0-3.0 for other indications (N= 427). The variability of INR for the total follow-up and the 2 months before the hemorrhage was calculated. The total follow-up was 1,963.26 years with 27,321 control tests. We observed 47 major bleeding episodes, including 2 fatal (central nervous system hemorrhages), in 37 patients. 49.5% of the patients had underlying diseases. The rate of major and fatal hemorrhage was 2.39 and 0.10 episodes per 100 patients year, respectively. Hemorrhagic complications were more frequently observed in patients with a more intense intended range (8.2% in the INR 3.5-4.5 group vs. 1.5% in the 2.0-3.0 INR group). The risk of major bleeding increased in patients with an achieved INR higher than 6 and in those with higher INR variability during follow-up. The estimated probability of bleeding also increased with time: it was 0.102% at 78 months, and at the beginning of therapy it was 0.006% and 0.007% at 1 and 4 months, respectively. The intensity of anticoagulation and the deviation of the INR from the target are the most important risk factors for bleeding in patients taking acenocoumarol. Monitoring the variability of INR can help identifying patients predisposed to bleeding. However, the screening for underlying disease should always be performed.