Anticoagulant levels in patients admitted for an acute myocardial infarction and treated with non-vitamin K antagonist oral anticoagulants

Abstract

Introduction

A significant rate of patients admitted for acute myocardial infarction (MI) are under chronic treatment with non-vitamin K antagonist oral anticoagulants (NOACs). Their initial anticoagulant management should be limited to an unfractionated heparin bolus during percutaneous coronary angiography (PCI), according to the new ESC guidelines. However, level of anticoagulants through standard laboratory tests or specific dosages could provide important information to adapt anticoagulation therapy and limit the early bleeding risk.

Objective

We aimed to investigate the levels of NOACs in patients admitted for an acute MI.

Method

Between February 1st, 2021 and January 31st, 2023, all consecutive adults admitted in coronary care unit for an acute MI and chronically treated with NOACs were prospectively included. Blood sampling was made on admission for anticoagulant assessment. NOAC concentrations (expressed in ng/mL) were measured using Liquid anti-Xa (Stago, Asnières sur Seine, France) for rivaroxaban and apixaban, and ECA-2 (Stago, Asnières sur Seine, France) for dabigatran, with specific set-up tests, according to the manufacturer's recommendations. Calibrations were performed using rivaroxaban, apixaban, dabigatran plasma calibrators (Stago, Asnières sur Seine, France). Patients were divided into 3 ranges according to levels of NOAC (Group 1: < 50 ng/mL, Group 2: 50–100 ng/mL, Group 3: > 100 ng/mL) taking account the haemostatic threshold of 50 ng/mL for surgery (except neurosurgery) or use of antidote and the through concentration of 100 ng/mL observed before next dose of twice-daily treatments.

Results

Rate of MI patients under chronic NOAC was 8,5% (n = 155). Their median (IQR) anticoagulant concentration was at 98 (51–179) ng/mL and the time from the last dose of NOACs was 495 (240–660) min. The main indication for chronic NOAC was atrial fibrillation. Among the 155 patients, 39 (25%), were in group 1, 42 (27%) in group 2 and 74 (48%) in group 3. Baseline characteristics were similar for the 3 groups (Table 1), including age, risk factors, type of NOAC and rate of PCI. However, there was a trend toward a higher rate of ST segment elevation MI in patients with elevated levels of anticoagulant.

Conclusion

Our prospective pilot study suggests that the dosage of NOACs could be a relevant guiding tool for anticoagulant strategy in patients with acute MI. However, its clinical utility and prognosis value remains to be determined in larger prospective multicentric studies.