Oral anticoagulant therapy, including factors Xa and 2a inhibitors has become more popular in recent years due to its efficacy and convenience in preventing thrombotic events and reducing the risk for stroke in patients with rosk factors (e.g. atrial fibrillation, deep venous thrombosis, pulmonary embolism). These drugs have replaced traditional therapies such as warfarin, which requires frequent dose adjustments and control blood samples. Warfarin also has a higher risk of bleeding events.

Many patients with atrial fibrillation, particularly old patients and those with comorbidities may have trouble achieving the dose and control requirements for warfarin therapy. On the other hand, Direct Oral Anticoagulant therapies do not require a close monitorization and have a lower risk of bleeding events, which makes them a more attractive option for many patients.

There is solid evidence behind the efficacy and safety of Direct Oral Anticoagulant therapies. Multiple clinical trials have demonstrated that Factor Xa inhibitors like rivaroxaban and apixaban are as effective as warfarin in preventing blood clots and reducing stroke risk in patients living with atrial fibrillation.

These challenges remark the need for new research that can improve our comprehension about the risk of bleeding associated to anticoagulant therapies and develop novel and more effective strategies for minimizing this risk.

Hence, an observational analysis about anticoagulant-associated intracranial hemorrhage may help identifying its incidence and prevalence, as well as treatment patterns and identifying any patient with risk factors linked to these events.

This information can be used to improve patient outcomes and guide future research.

Work Hypothesis: The majority of intracranial hemorrhage events are associated with heparin, low molecular weight heparin and warfarin instead of Factor Xa inhibitors or direct thrombin inhibitors. Nevertheless, the growing use in recent years of factor Xa inhibitors can increase the number of this therapy related bleeding events.

Study observational. The total number of subjects for this study will be determined by the number of patients with intracranial bleeding associated with anticoagulant therapy on the clinical records.

Primary objective: To identify the incidence and prevalence of intracranial bleeding events associated to oral anticoagulant therapy including vitamin k antagonists, factor Xa inhibitors and factor 2a inhibitors.

Secondary objective:

• To identify mortality related to intracranial bleeding associated with oral anticoagulant therapy, including vitamin K antagonists, factor Xa inhibitors and factor 2a inhibitors.
• To identify patients´ characteristics correlated with intracranial hemorrhage associated with oral anticoagulants.
• To identify treatment patterns: anticoagulant-associated intracranial bleeding management, including clinical, pharmacological, surgical, and interventional treatments, as well as procoagulant therapies.

Sample size Justification / Statistical Analysis: Non probabilistic, incidental reasoned selection.

The sample size will be determined by the number of patients with intracranial hemorrhage associated with anticoagulation in the clinical records. All electronic medical records that meet the inclusion criteria will be included in the analysis.

Descriptive analysis:

Descriptive statistics will be used for demographic and clinical characteristics of the study sample. This will include measures of central tendency (mean, median) and measures of dispersion (standard deviation, range).

Analytic (Inferential) analysis:

A univariate analysis will take place in order to examine the relationship between demographic and clinical variables with anticoagulation-associated intracranial hemorrhage This will include chi-squared tests for categorical data and T-tests or Mann-Whitney U Tests for continuous data.

A multivariable logistic regression analysis will be done to identify independent predictors of intracranial bleeding associated with anticoagulant therapy. The variables to include in the model will be determined by de univariate analysis results.

The investigators will consider a p-value under 0.05 for statistical significance.

Inclusion Criteria:

• Age >18 years
• Intracranial hemorrhage diagnosis and concomitant oral anticoagulant therapy
• Available clinical record from January 2015 to July 2023

Exclusion Criteria:

• Non available clinical record
• Patients that did not complete follow up on days 30 and 90 after an intracranial bleeding.

All outpatients and/or hospitalized patients and patients from the emergency room of the National Institute of Neurology and Neurosurgery Manuel Velasco Suárez with intracranial hemorrhage diagnosis under anticoagulant therapy such as Vitamin K antangonists, Factor Xa inhibitors or direct thrombin inhibitors.