Abstract

Coronary microvascular obstruction (MVO) is an injury of the microcirculation of the heart muscle. It typically follows successful recanalization of the blocked coronary artery (primary occlusion) after a heart attack. MVO leads to under-perfusion of the affected tissue and has a negative impact on patient outcomes. Next to other occluding factors, MVO may be caused by microthrombi (debris from the primary occlusion) which occlude vessels of less than 200µm diameter.

For the systematic study of MVO, we have developed a multi-scale in vitro model which comprises a microfluidic chip modeling a branching microvascular tree with vessel diameters ranging from 700 to 50µm. The chip is integrated into a model of the coronary circulation which is coupled to a left-heart mock loop. This experimental setup provides physiological flow conditions for the whole model. MVO is induced by injecting porcine microthrombi (~200µm) into the microfluidic chip where they randomly distribute and occlude some of the microchannels.

We will discuss the distribution of the microthrombi in the microfluidic chip and will characterize their effect on the perfusion of the chip. The reduced perfusion also limits the delivery of thrombolytic drugs toward the microthrombi. We will study the efficiency of thrombolysis in a microfluidic chip for different infusion protocols of available thrombolytic drugs and we will show that microthrombi can be resolved after a primary incubation time of 90 seconds at high drug concentration over the course of 20 minutes.

Biography

Dominik Obrist is Professor of Cardiovascular Engineering at the ARTORG Center for Biomedical Engineering Research of the University of Bern. He holds a degree in mechanical engineering from ETH Zurich and earned his doctoral degree in 2000 at the Department of Applied Mathematics of the University of Washington. From 2000 to 2005, he worked for the supercomputer company Cray Inc. In 2005, Dominik Obrist returned to academia as a senior researcher at the Institute of Fluid Dynamics of ETH Zurich, where he established a research group for biomedical fluid dynamics. He is co-founder of the start-up URODEA, which invented the world’s first non-invasive solution for urinary retention. His main research interests include the design of heart valve prostheses and the development of novel technology for the diagnosis and treatment of microvascular diseases.