Blood clots have emerged as one of an increasing number of deadly side effects of the novel coronavirus in some patients. Cockrell School of Engineering researchers are embarking on a project to learn more about the onset of thromboembolism, the obstruction of a blood vessel by a clot that can cause everything from strokes to heart attacks to pulmonary embolisms, as a result of COVID-19.

The new research will use the concept of fracture mechanics – the study of how and why things crack and break – to understand the relationship between coronavirus and blood clots. The research team aims to compare the blood of coronavirus patients with that of healthy people to see whether it is more likely to break apart under pressure.

"If COVID patients show a higher propensity for blood clots to break off, that would be monumental," said Manuel Rausch, an assistant professor in the Department of Aerospace Engineering and Engineering Mechanics and the Department of Biomedical Engineering. "We could then build a test — using just a few milliliters of blood — to predict whether they are more at risk for heart attacks, strokes and other side effects of thromboembolic disease that develops in COVID patients."

Though heart attacks, strokes and other similar medical emergencies are typically categorized separately, they all can result from blood clots, making thrombosis one of the most common causes of death.

Rausch and his team recently received approval to collect and analyze blood from COVID patients. That paves the way to begin experiments to mold clotted, or coagulated, blood so it can be analyzed.

The team has submitted the first of several papers on the topic. It looks at the mechanics of blood clots but does not include any COVID blood experiments.

Blood is a dynamic material, solidifying when it touches a surface or the skin is cut, to stop the bleeding. Blood clots aren't inherently harmful, as they are necessary to stanch bleeding and repair torn vessels. However, when clots break off and travel through the bloodstream, that's when they can become dangerous and lead to strokes and heart attacks. Renegade clots plug up blood vessels, keeping blood from traveling to vital organs.

For the experiment, the team will induce blood to clot around a mold they will use to make it into a thin sheet. They will partially cut it. A mechanical device will attempt to rip it along the cut line. The team will compare the respective "fracture points" of the different blood samples to determine which are more resistant to breaking apart. The lower the fracture point, the more likely the blood is to break off and put a patient at risk for clotting issues.

Rausch sees broader applications of the research, which is funded through the K.C. Williams Faculty Excellence Fund, beyond working with COVID patients. It could be used to measure whether drugs in development weaken blood and make clots more likely to break off and put people who take the drug at risk. Rausch said he wants to build a model that can determine the likelihood blood clots will fracture under different circumstances.

Rausch specializes in using computational tools to understand the mechanics and behavior of complicated biological soft tissues in the body. He’s fascinated by blood and has been working with it since his postdoctoral studies at Yale University several years ago. He's also followed the progress of fracture mechanics, which emerged during World War II to understand why battleships suddenly failed and has recently been adapted to study the mechanics of the human body.

When the COVID pandemic arrived, Rausch said his research projects ground to a halt as labs closed. He worked on a couple of different coronavirus projects, making masks and parts to help solve ventilator shortages. But those projects didn't fit his areas of expertise.

When he started reading reports about COVID patients experiencing strokes, heart attacks and other complications due to blood clots, Rausch started to put together the idea. 

“I immediately thought ‘this is exactly what I do,’” he said.

Rausch has a unique specialty in combining computational engineering with a focus on biomechanics. His mentor at UT is K. Ravi-Chander, a professor in the Department of Aerospace Engineering and Engineering Mechanics and the editor-in-chief of the International Journal of Fracture. Rausch’s interest in blood and fracturing, combined with the expertise to lean on for guidance helped quickly galvanize the team and idea for the project.

“I've always been interested in blood clots, and I always wanted to study fracture mechanics,” Rausch said. “This is an opportunity to step in and use my expertise to try to contribute to the discovery of a potentially new mechanism and translate really basic science into clinical advancement.”