While early news in January described only the hallmark symptoms of coronavirus - fever, fatigue and an unrelenting cough - new and ever-increasing cases around the world draw a complex picture.
For some patients, we now know, SARS-CoV-2 doesn’t just ravage the lungs. The virus can also induce serious cardiovascular complications - some of which turn deadly. To understand what’s happening, researchers are grasping for more data. Eventually, the right algorithm could help catch looming heart problems in COVID-19 patients - hopefully, before lasting damage is done.
Collin Stultz, a biomolecular engineer and practicing cardiologist at Massachusetts General Hospital (MGH), is working on one such project with J-Clinic. The aim is to create an algorithm to predict heart damage in patients with COVID-19 using readily available data - which would bypass the need for additional invasive tests that provide more detailed information.
For Stultz and other researchers, many clues about cardiovascular complications come out of published data, arising mainly from Wuhan, China. Several studies, which collectively summarize the clinical experience with thousands of patients, provided useful insights into the relationship between cardiovascular disease and COVID-19.
“By the time the disease was prevalent in the U.S., we had a little more than anecdotal evidence,” Stultz says. From case reports and patient registries, it is apparent that people with advanced age, diabetes, high blood pressure, chronic lung disease and cardiovascular disease fare the worst after contracting COVID-19.
Many patients - in some cases, up to a third of them - present evidence of myocardial injury, or damage to the heart, Stultz says. In one study from Wuhan, approximately 20% of 416 hospitalized patients with Covid-19 had evidence of heart damage. In the end, 51% of those patients died - compared to just 4.5% of patients without signs of injury.
For now, underlying mechanisms of heart damage remain a mystery. Coronavirus binds to angiotensin converting enzyme-2 (ACE2), which is found on the surface of a variety of different cell types, including cells in the lung, vasculature, and the heart. Some have hypothesized that SARS-CoV-2 may affect cardiac function by directly attacking cells in the heart muscle, sparking an inflammatory response. The theory could explain why certain people are at higher risk for bad outcomes: patients with heart disease or high blood pressure often take medications that upregulate ACE2 in the body, making them more susceptible to heart damage.
But so far, “all of these things are unknown,” Stultz says.
Clinicians can assess damage to the heart by measuring the level of certain proteins in the blood. But after seeing an elevation in these markers, in some ways it’s too late. “You’d like to be able to predict these things before somebody has signs and symptoms of myocardial injury,” Stultz says.
As the heart starts to fail, pressures in chambers of the heart often go up. To measure those pressures, doctors must thread a catheter through a deep vein, and eventually into the heart and pulmonary arteries. The procedure is invasive and comes with its own set of risks. The algorithm that Stultz is working on is meant to be a substitute for this procedure, predicting the risk for heart damage using EKG and early lab values. While the project is “really in its infancy,” he hopes it can be adapted to help COVID-19 patients. Early non-invasive measurement of these pressures in patients with COVID-19 may provide additional information on who is most likely to have the direst outcomes.
Knowing who is at high risk for heart damage could be helpful in several ways. It could help sort patients based on who needs more monitoring, and who would benefit from being transferred to the ICU sooner. Knowing the risk might also shift the calculus for who should try medications currently being investigated for treating COVID-19.
Currently, Stultz is working to get approval to gather data from COVID-19 patients at MGH and Brigham and Women’s Hospital. “[At J-Clinic], we have a route that we could potentially contribute to,” he says. “I’m hopeful we can come together and tease out the most important problems.”