Warfarin and three direct oral anticoagulants are associated with different patterns of thrombus-formation inhibition under flow conditions, patterns which can be identified by means of visual analysis using a microchip flow chamber system, a new study finds.

The microchip in this case was the AR chip and the system, the Total Thrombus-formation Analysis System (T-TAS), which offers a novel way to obtain quantitative assessment of whole-blood thrombogenicity. The paper was published online Aug. 7 in Scientific Reports.

“We sought to clarify the different mechanisms responsible for the suppression of bleeding events using the Total Thrombus-formation Analysis System (T-TAS), a flow-microchip chamber with thrombogenic surfaces,” said the researchers, led by Masanobu Ishii, with the department of cardiovascular medicine at Kunamoto University Graduate School of Medical Sciences in Kunamoto, Japan.

One-hundred and twenty patients with atrial fibrillation (AFib) comprised the study population. All the patients were > 20 years of age and had undergone radiofrequency catheter ablation for AFib at Kumamoto Hospital between September 2013 and August 2015. The researchers assigned the patients to one of four study groups: warfarin, dabigatran, rivaroxaban, and apixaban.

The researchers took blood samples for analysis from the patients on the day of RFCA (off-coagulant) and one month after RFCA (on-coagulant).

“The findings suggested that visual analysis of the AR-chip can identify the differential inhibitory patterns of warfarin and DOACs on thrombus formation under flow conditions,” they wrote.

This study is, they believe, the first one to determine the differential mechanism of antithrombotic effects in patients treated with warfarin and DOACs, using T-TAS.