A study led by University of California- Los Angeles Health Sciences (UCLA) used 3D-printed 'blood vessels' to explain how Covid-19 virus increases the risk of stroke. Researchers did a study about the running fluid spiked with a COVID-19-like protein through a 3D-printed model of the arteries of a patient who had suffered a stroke. Although Covid-19 was first identified by its severe respiratory symptoms, little is known about how the virus increases the risk for stroke.