Is an International Normalized Ratio (INR) of 1.1, Prothrombin Time (PT) of 11.8, and Partial Thromboplastin Time (PTT) of 36.1 acceptable in a patient on Eliquis (apixaban) with bruising on the arm?

From the Guidelines

The coagulation levels (PT 11.8, INR 1.1, PTT 36.1) are not accurately reflective of the anticoagulant effect of Eliquis (apixaban) in this patient, and the presence of bruising on the arm is likely related to the expected anticoagulant effect of the medication. Eliquis is a direct oral anticoagulant (DOAC) that inhibits factor Xa, and its anticoagulant activity is not reflected in routine coagulation tests like PT/INR or PTT 1. The PT/INR and PTT tests are commonly used to monitor patients on warfarin or heparin, but they are not reliable for monitoring the anticoagulant effect of DOACs like Eliquis 1.

Some key points to consider in this patient's case include:

• The patient's PT/INR and PTT results are within normal range, but this does not necessarily indicate that the patient is not at risk for bleeding complications while on Eliquis 1.
• The bruising on the arm is a common side effect of Eliquis and may be related to the anticoagulant effect of the medication 1.
• If the bruising is extensive, spreading, or accompanied by other bleeding symptoms (such as blood in urine, stool, or gums), the patient should seek immediate medical attention 1.
• For patients on Eliquis with concerning bleeding, anti-factor Xa assays can be used to measure drug levels if available, though these are not routinely performed 1.
• Viscoelastic coagulation tests, such as thromboelastography (TEG) or rotational thromboelastometry (ROTEM), may be useful in detecting coagulopathy associated with DOACs, but their utility is limited in the emergency setting due to the need for specialized equipment and trained personnel 1.

In terms of management, it is essential to weigh the benefits and risks of continuing Eliquis in this patient, considering the presence of bruising and the potential for bleeding complications 1. However, the presence of some bruising alone, without other bleeding symptoms, does not necessarily indicate an inappropriate anticoagulation level while on Eliquis 1.

From the FDA Drug Label

Apixaban tablets should be discontinued at least 48 hours prior to elective surgery or invasive procedures with a moderate or high risk of unacceptable or clinically significant bleeding [see Warnings and Precautions (5. 2)]

Switching from warfarin to apixaban: Warfarin should be discontinued and apixaban started when the international normalized ratio (INR) is below 2. 0.

The patient's INR is 1.1, which is below 2.0, but the patient is already on apixaban (Eliquis). The coagulation levels provided are:

• PT: 11.8
• INR: 1.1
• PTT: 36.1 The presence of bruising on the arm may indicate an increased risk of bleeding. However, the provided information does not directly answer whether these coagulation levels are acceptable for a patient on apixaban. The FDA label does not provide a clear answer to what constitutes acceptable coagulation levels for patients on apixaban. Therefore, a conservative clinical decision would be to monitor the patient closely for signs of bleeding or thrombosis and consider consulting with a specialist or the patient's primary care physician for further guidance 2.

From the Research

Coagulation Levels on Eliquis

• The patient's coagulation levels are as follows: Pt 11.8, INR 1.1, PTT 36.1, while on Eliquis (apixaban) and experiencing bruising to the arm.
• According to 3, apixaban is associated with a notable increase in INR in hospitalized patients, with 84.5% of patients having an elevated INR on day 1 of therapy.
• The study 4 found that PT values significantly correlated between two reagents and were prolonged in patients taking apixaban, although there was significant interpatient variability.
• Another study 5 showed that apixaban affects thrombin generation parameters, including lag-time, endogenous thrombin potential, and thrombin-peak, but has little effect on PT or APTT.
• The comparison of apixaban and rivaroxaban effects on PT and APTT using various reagents 6 found that TriniCLOT PT Excel S was the only reagent sensitive to apixaban, while all PT reagents were sensitive to rivaroxaban.
• A practical laboratory guide 7 concluded that PT and/or dilute PT cannot be used to assess apixaban pharmacodynamic properties, and more specific and sensitive assays such as chromogenic FXa assays are required.

Acceptability of Coagulation Levels

• The patient's INR of 1.1 is slightly elevated, which is consistent with the findings of 3 that apixaban can increase INR in patients.
• However, the clinical significance of this elevation is unclear, as stated in 3.
• The presence of bruising on the arm may indicate an increased risk of bleeding, but the coagulation levels alone do not provide a clear indication of the acceptability of the patient's coagulation status while on Eliquis.
• Further evaluation and consideration of the patient's overall clinical condition, as well as the use of more specific and sensitive assays, may be necessary to determine the acceptability of the patient's coagulation levels.