MRI Monitor: Screen or Pass?
By Beth W. Orenstein
Vol. 22 No. 3 P. 6
Should student athletes with COVID-19 undergo CMR?
COVID-19 is not solely a respiratory infection. It can also cause myocarditis, a viral infection that can weaken the heart muscle and cause arrhythmias and sudden death. According to the Myocarditis Foundation, myocarditis is a rare condition—affecting approximately 22 out of every 100,000 people worldwide each year. However, myocarditis is a recognized cause of death among student athletes, even in those who had no known heart trouble. A report published by the Myocarditis Foundation in 2005 found that 75 athletes between the ages of 13 and 25 die each year from myocarditis.
So, a question has arisen: Does strenuous exercising during or after being infected with COVID increase the risk of developing myocarditis? Studies are ongoing and producing different answers to this important question.
A study published in September 2020 in JAMA Cardiology of 26 competitive athletes at The Ohio State University found a sizable number to have myocarditis injuries after recovering from COVID. Cardiac MR (CMR) showed that four (15%) of the athletes had findings suggestive of myocarditis, while another eight (30.8%) exhibited findings suggestive of prior myocardial injury. However, in December 2020, researchers at Vanderbilt University Medical Center in Nashville published a study of 59 student athletes in the American Heart Association’s journal Circulation. It found a much lower degree of myocarditis in competitive athletes than what was reported by Ohio State. The degree of myocarditis found by CMR in Vanderbilt athletes was only 3%.
Dan Clark, MD, MPH, first author of the Vanderbilt study and an instructor of cardiovascular medicine as well as an adult congenital heart disease fellow, says the differences in the findings are extremely important. While he believes that more multicenter research involving larger sample sizes is needed, he also believes that the initial degree of myocarditis in college athletes found by MRI may be unnecessarily alarming. “Prior publications, including The Ohio State University study and a study in Germany, suggested a much higher rate of myocarditis,” Clark says. “I think it’s reassuring that our study showed there is a much more modest degree of myocarditis from COVID-19 in athletes than originally suspected.”
The German study also used CMR. Of 100 patients recovering from COVID, 78% had cardiac involvement and 60% had ongoing myocardial inflammation independent of preexisting conditions. None of the patients were identified as athletes.
Is CMR Necessary?
Since publishing their paper, the Vanderbilt researchers have screened additional student athletes—almost double the initial amount—and the same small percentage of myocarditis seems to be holding true, Clark says. They plan to publish their new findings shortly.
Clark cautions, however, that not all their news on myocarditis and COVID in athletes is good. The researchers would not have found myocarditis, even in the 3%, had they not performed CMR.
“While our first message is reassuring that the incidence of myocarditis in athletes is much lower than previously suspected, it’s disappointing news that our athletes with myocarditis would have been missed by other screening methods,” Clark says. “If they had not undergone a cardiac MR, they would not have known they had myocarditis.” CMR produces black and white scans, which can be used to create a 3D view of the heart muscle. It is considered to be among the best available tools for identifying inflammation and scar tissue.
The Vanderbilt study evaluated 59 athletes representing different sports—endurance and static insertional or sports that blended the two—who had recovered from COVID-19 and compared them with a healthy control group as well as a group of 60 athletic controls. All of the students underwent blood work, clinical exams, EKG, echocardiograms, and other cardiovascular screenings. All of the results were normal.
“Initially, we hoped that the standard screening tests for athletes would be definitive because we wanted something that was widely available and quick,” Clark says.
The researchers had planned to use CMR only if absolutely necessary. But because it has been well documented that COVID-19 may affect the heart, they decided to dig deeper. When they did, they found more scarring in healthy heart muscle than expected. The athletic control group without COVID-19 showed 24% scarring in the heart muscle, while those athletes who had recovered from COVID had a 27% scarring ratio. “So, it’s a very similar rate between the two groups,” Clark says.
It’s not uncommon for athletes to have athletic remodeling of their hearts. “There’s no definitive literature that tells us exactly what athletic remodeling is,” Clark says, but generally it is a group of molecular, cellular, and interstitial changes that manifest clinically as changes in size, mass, geometry, and function of the heart after injury. Athletes often have a small area of benign scarring due to athletic remodeling. He notes that myocarditis after COVID tends to be in a similar spot. The latter is rather important information because, if clinicians aren’t aware that this area of scarring is common in healthy athletes, they may attribute the scarring they see on MR to consequences of COVID, he says, “and they could restrict some athletes from competition.”
Last fall, the American Medical Society for Sports Medicine and the American College of Cardiology recommended that any athlete diagnosed with COVID be asymptomatic for at least 10 days before considering returning to exercise and that they undergo cardiac screening before resuming participation in sports. According to these groups, the screening should include a review of symptoms, physical exams, EKG, blood tests for damage of heart muscle cells, and/or an echocardiogram or ultrasound of the heart. If there are no signs of myocarditis, the societies recommend a gradual increase in exercise intensity over at least one week and monitoring for symptoms.
Symptoms of myocarditis are chest tightness, exercise intolerance, and shortness of breath. The societies recommended CMR only if the suggested screenings show positive findings. Clark believes they did not recommend CMR because of the cost and availability of the imaging exam. If Vanderbilt had strictly followed these recommendations, he notes, “we would have missed the myocarditis in the few recovering athletes where we found it.”
What should other schools do about screening their athletes for myocarditis after COVID, before allowing them to return to play? Vanderbilt is continuing to screen all of its athletes with CMR, but, Clark says, “Hopefully, our next paper will shed some more light on that discussion.”
Do the athletes’ chances for developing myocarditis change if their COVID is mild or severe? Do CMR screening recommendations change with the severity of the disease? Clark says those are some of the questions the researchers are planning to study.
“In our initial study,” he says, “we didn’t have a large enough sample size to really explore that specific topic, but, with our larger group, that’s what we’re hoping to do. We want to answer the question: How much do symptoms predict whether there is cardiovascular sequelae of COVID-19? The short answer is, no one really knows yet.”
— Beth W. Orenstein, of Northampton, Pennsylvania, is a freelance medical writer and regular contributor to Radiology Today.