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Using cardiac MRI, researchers found myocardial injury in more than half of patients hospitalized with severe COVID-19 and elevated troponin a few months after hospital discharge. “We found evidence of high rates of heart muscle injury that could be seen on the scans a month or two after discharge. Whilst some of this may have been preexisting, MRI scanning shows that some were new, and likely caused by COVID-19,” Marianna Fontana, MD, PhD, professor of cardiology at University College London, said in a press release. “Importantly, the pattern of damage to the heart was variable, suggesting that the heart is at risk of different types of injury. While we detected only a small amount of ongoing injury, we saw injury to the heart that was present even when the heart’s pumping function was not impaired and might not have been picked up by other techniques. In the most severe cases, there are concerns that this injury may increase the risks of heart failure in the future, but more work is needed to investigate this further.”
For this analysis, researchers included 148 patients from six hospitals (mean age, 64 years; 70% men) with severe COVID-19 infection and elevated troponin levels, all requiring hospitalization (32% requiring mechanical ventilation), who underwent convalescent cardiac MRI and adenosine stress perfusion at a median of 68 days after discharge. “Raised troponin levels are associated with worse outcomes in COVID-19 patients. Patients with severe COVID-19 disease often have preexisting heart-related health problems, including diabetes, raised blood pressure and obesity,” Fontana said in the release. “During severe COVID-19 infection, however, the heart may also be directly affected. Unpacking how the heart can become damaged is difficult, but MRI scans of the heart can identify different patterns of injury, which may enable us to make more accurate diagnoses and to target treatments more effectively.”
Myocardial injury in COVID-19
Patients with abnormal troponin levels were offered a cardiac MRI after discharge and were compared with a control group of patients who did not have COVID-19 and 40 healthy volunteers. Researchers observed that left ventricular function was normal in 89% of the overall cohort (mean ejection fraction, 67%). Late gadolinium enhancement and/or ischemia was found in 54% of participants hospitalized for severe COVID-19 infection, which included a myocarditis-like scar in 26%, MI and/or ischemia in 22% and dual pathology in 6%. According to the study, myocarditis-like injury was limited to three or fewer myocardial segments in 88% of patients with no LV dysfunction, of which 30% had active myocarditis. In addition, MI was observed in 19% and inducible ischemia in 26% of patients who underwent stress perfusion after discharge. Moreover, of patients with ischemic injury, 66% had no prior history of coronary disease. Researchers found no evidence of diffuse fibrosis or edema in the remote myocardium.
Two new opportunities
“These findings give us two opportunities,” Fontana said in the release. “Firstly, to find ways of preventing the injury in the first place, and from some of the patterns we have seen, blood clotting may be playing a role, for which we have potential treatments. Secondly, detecting the consequences of injury during convalescence may identify subjects who would benefit from specific supporting drug treatments to protect heart function over time.”
Findings published in European Heart Journal (Feb. 18, 2021):
