The combined role of hematocrit and shear flow on the morphology of platelet aggregates by Fast Fourier Transform and 4D confocal microscopy

The morphology of platelet aggregates is emerging as a key indicator for identifying thrombotic risk and coagulation disorders and is proving instrumental in early diagnosis and personalized antithrombotic therapies. Current methods lack standardized approaches for analyzing the morphology of mural platelet aggregates and often overlook the impacts of hematocrit and shear rate, despite their crucial role in platelet aggregation. To address this gap, here, we propose a standardized and versatile method for quantitatively assessing platelet aggregate morphology, focusing on the combined effects of hematocrit and shear rate. Our approach integrates microfluidics and high-resolution confocal microscopy, complemented by dynamic 3D reconstruction tools and fast Fourier transform analysis. Our results reveal that shear rate primarily governs the flow alignment of platelet aggregates and thrombus occlusive capacity. Additionally, we find that hematocrit plays a crucial role in stabilizing thrombus adhesion to the vessel wall, regulating plateletcovered area and aggregate width in a flow-dependent manner.