From the Guidelines
An elevated International Normalized Ratio (INR) indicates that a patient's blood is too thin, which can increase the risk of bleeding.
What is INR?
- The INR is a test used to measure the time it takes for blood to clot and is primarily used to monitor patients on warfarin therapy.
- It is calculated by comparing the patient's prothrombin time (PT) to a standard control sample, and then adjusting for the sensitivity of the thromboplastin used in the test 1.
Target INR Range
- The target INR range varies depending on the patient's condition, but for most patients with atrial fibrillation or mechanical heart valves, the target range is between 2.0 and 3.0 1.
- An INR above 3.0 increases the risk of bleeding, particularly intracranial hemorrhage (ICH) when INR > 3.5 1.
Managing Elevated INR
- If a patient's INR is elevated, the healthcare provider may need to adjust their warfarin dose or recommend vitamin K to help lower the INR 1.
- In cases of active bleeding, more aggressive measures such as fresh frozen plasma and intravenous vitamin K may be necessary 1.
Importance of INR Control
- Maintaining an INR within the therapeutic range is crucial to minimize the risk of thromboembolic events and bleeding complications 1.
- Regular monitoring and patient education can help improve INR control and reduce the risk of complications 1.
From the Research
Elevated International Normalized Ratio (INR) Meaning
An elevated International Normalized Ratio (INR) is associated with a high risk of bleeding, as seen in patients with INR higher than 9 2. The causes of an elevated INR can vary, including:
- Bleeding events, which can result in an elevated INR in patients previously stable on warfarin 3
- Post-thrombolytic coagulopathy in acute ischemic stroke patients after treatment with tissue plasminogen activator (tPA) 4
- Vitamin K deficiency, liver disease, or the use of direct oral anticoagulants (DOACs) in intensive care unit (ICU) patients 5
- Chronic liver disease (CLD) or warfarin therapy, with different risks of hemorrhage associated with elevated INR in these two cohorts 6
Risks Associated with Elevated INR
The risks associated with an elevated INR include:
- Bleeding complications, such as symptomatic intracerebral hemorrhage 4
- Increased risk of hemorrhage, particularly in patients with CLD or those taking warfarin with supratherapeutic INR values 6
- Poor prognosis, with high mortality rates in patients without anticoagulant treatment and elevated INR 2
Management of Elevated INR
The management of elevated INR depends on the underlying cause, but may include:
- Withholding warfarin or giving vitamin K treatment, although this may be ineffective in reducing INR within 24 hours 2
- Plasma infusion, which can immediately drop the INR to a safer range 2
- Caution when transfusing plasma to reverse an elevated INR in ICU patients, as this practice may be avoidable or inappropriate in certain cases 5