Coagulation Testing in Acute Ischemic Stroke Patients Taking Non–Vitamin K Antagonist Oral Anticoagulants

Aim: The aim of this study was to establish whether non-vitamin K antagonist oral anticoagulants (NOACs) are superior to warfarin in preventing stroke recurrence for atrial fibrillation (AF) patients with an ischemic or hemorrhagic stroke at the baseline. Methods: From 1 January 2009 to 31 December 2017, stroke patients with AF treated with oral anticoagulants in the National Health Insurance Research Database in Taiwan were enrolled. The study was retrospective cohort design. Outcome measures were ischemic and hemorrhagic stroke recurrence. The Cox proportional hazard model was used to obtain the hazard ratio (HR). Results: In total, 39,840 stroke patients with AF treated with NOAC and 42,583 treated with warfarin were identified. NOACs were superior to warfarin in preventing all recurrent stroke [adjusted HR: 0.67, 95% confidence interval (CI), 0.63–0.71, p < 0.001]. Results for the ischemic stroke population were the same as that for all types for stroke (adjusted HR: 0.66, 95% CI, 0.62–0.70, p < 0.001). For the hemorrhagic stroke population, NOACs were equivalent to warfarin in preventing ischemic stroke (adjusted HR: 1.11, 95% CI, 0.86–0.43, p < 0.001), but NOACs were superior to warfarin in preventing hemorrhagic stroke (adjusted HR: 0.64, 95% CI, 0.55–0.74, p < 0.001). Conclusions: NOACs were generally superior to warfarin in terms of efficacy and safety in previous stroke patients. The robustness of our findings was verified and should add new information to current recommendations for Asian stroke patients in selecting NOACs.

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Coagulation Testing in Acute Ischemic Stroke Patients Taking Non-Vitamin K Antagonist Oral Anticoagulants

American Journal of Clinical Pathology ◽

10.1093/ajcp/aqaa161.222 ◽

2020 ◽

Vol 154 (Supplement_1) ◽

pp. S101-S102

Author(s):

Y S Kamel

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Oral Anticoagulants ◽

False Negative ◽

International Normalized Ratio ◽

Vitamin K Antagonist ◽

Activated Partial Thromboplastin Time ◽

Test Results ◽

Coagulation Testing ◽

Coagulation Tests

Abstract Introduction/Objective In patients who present with acute ischemic stroke while on treatment with non-vitamin K antagonist oral anticoagulants (NOACs), coagulation testing is necessary to confirm the eligibility for thrombolytic therapy. We evaluated the current use of coagulation testing in routine clinical practice in patients who were on NOAC treatment at the time of acute ischemic stroke. Methods Prospective multicenter observational RASUNOA registry (Registry of Acute Stroke Under New Oral Anticoagulants). Results of locally performed nonspecific (international normalized ratio, activated partial thromboplastin time, and thrombin time) and specific (antifactor Xa tests, hemoclot assay) coagulation tests were documented. The implications of test results for thrombolysis decision-making were explored. Results In the 290 patients enrolled, nonspecific coagulation tests were performed in ≥95% and specific coagulation tests in 26.9% of patients. Normal values of activated partial thromboplastin time and international normalized ratio did not reliably rule out peak drug levels at the time of the diagnostic tests (false-negative rates 11%-44% [95% confidence interval 1%-69%]). Twelve percent of patients apparently failed to take the prescribed NOAC prior to the acute event. Only 5.7% (9/159) of patients in the 4.5-hour time window received thrombolysis, and NOAC treatment was documented as main reason for not administering thrombolysis in 52.7% (79/150) of patients. Conclusion NOAC treatment currently poses a significant barrier to thrombolysis in ischemic stroke. Because nonspecific coagulation test results within normal range have a high false-negative rate for detection of relevant drug concentrations, rapid drug-specific tests for thrombolysis decision-making should be established.

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Abstract WP188: Clinical Severity and Timing of Onset for Acute Ischemic Stroke and TIA During Oral Anticoagulation Using Warfarin or Non-vitamin K Antagonist Oral Anticoagulants

Stroke ◽

10.1161/str.47.suppl_1.wp188 ◽

2016 ◽

Vol 47 (suppl_1) ◽

Author(s):

Kenta Seki ◽

Masatoshi Koga ◽

Hiroshi Yamagami ◽

Shoji Arihiro ◽

Kazuyuki Nagatsuka ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Vitamin K ◽

Oral Anticoagulants ◽

Vitamin K Antagonist ◽

Clinical Severity ◽

Neurological Deficits ◽

Chads2 Score ◽

Nihss Score ◽

Stroke Center

Background and Purpose: In Japan, four non-vitamin K antagonist oral anticoagulants (NOACs) became available in clinical use for prevention of stroke in patients with non-valvular atrial fibrillation (NVAF) between 2011 through 2014. The aim of this study is to determine underlying characteristics and ischemic stroke/TIA features of patients taking NOACs or warfarin, a vitamin K antagonist (VKA) prior to stroke/TIA. Methods: We enrolled oral anticoagulant (OAC) users for NVAF, who were admitted to our stroke center for acute ischemic stroke/TIA between March 2011 and June 2015 (ClinicalTrials.gov Identifier: NCT02251665). Results: 381 OAC users who developed stroke/TIA were studied. Of these, 63 patients took NOACs [23 women, 77±9 years, dabigatran in 33 (7 taking higher dosage between two official ones), rivaroxaban in 22 (5), apixaban in 8 (3), edoxaban in none] and 318 took VKA (143 women, 79±8 years). There were no significant differences between NOACs users and VKA users in sex, age, CHADS2 score (median 3[IQR 2-4] vs. 3 [2-4]), history of ischemic stroke/TIA (57% vs. 51%) and prior antiplatelet use (25% vs. 24%). Admission NIHSS score tended to be lower (3 [1-15] vs. 7 [2-20], p=0.076) and discharge NIHSS score was lower (1[0-5] vs 3[1-13], p=0.032) in NOACs users. Discharge mRS (2 [1-4] vs. 3 [1-4]) and mortality during hospitalization (5% vs. 4%) were similar between two groups. A different point was timing of stroke/TIA after initiating OAC ; 6% of NOAC users developed events within 14 days and 32% within 3 months, whereas 4% and 7% of VKA users did, respectively (p<0.001). Congestive heart failure tended to be more common in NOACs users developing events within 3 months than those developing events later (43% vs. 19%, p=0.070). Conclusions: NOACs users tended to show milder neurological deficits than VKA users during acute hospitalization of ischemic stroke/TIA, although discharge mRS was similar. NOACs users often developed stroke/TIA within the initial 3 months after initiating OAC, particularly between 14 days and 3 months. One would take special care of ischemic events during early months after initiating NOACs.

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