Point-of-Care International Normalized Ratio Testing Accelerates Thrombolysis in Patients With Acute Ischemic Stroke Using Oral Anticoagulants

Background and Purpose— Thrombolysis in patients using oral anticoagulants (OAC) and in patients for whom information on OAC status is not available is frequently delayed because the standard coagulation analysis procedure in central laboratories (CL) is time-consuming. By using point-of-care (POC) coagumeters, international normalized ratio (INR) values can be measured immediately at the bedside. The accuracy and effectiveness of POC devices for emergency management in acute ischemic stroke has not been tested. Methods— In phase 1, the reliability of emergency INR POC measurements in comparison to CL was determined. In phase 2, patients with ischemic stroke admitted within the time frame for systemic thrombolysis and who were either using OAC or for whom information on OAC status was not available were enrolled. Patients received thrombolysis if POC INR was ≤1.5. Precision and time gain was recorded for INR as measured by POC vs CL. Results— In phase 1 (n=113), Bland-Altman analysis showed close agreement between POC and CL, and Pearson correlation was highly significant (r=0.98; P<0.01). In phase 2, 48 patients were included, of whom 70.8% were using OAC; 23 patients received thrombolysis. After subtracting the time needed for the diagnostic work-up, the net time gain was 28±12 minutes (mean±SD). Conclusions— Measuring INR by POC in an emergency setting is sufficiently precise in OAC acute stroke patients and substantially reduces the time interval until INR values are available and therefore may hasten the initiation of thrombolysis.