Myocardial Inflammation After COVID-19 Improves Over Short-Term Follow-Up

Although previous cardiac magnetic resonance imaging (MRI) studies examined myocardial disease in patients who recovered from COVID-19, there is a lack of data regarding persistent changes in myocardial metabolism in this patient population.

Accordingly, a recent cohort study of patients recently recovered from COVID-19 identified myocardial inflammation on fluorodeoxyglucose–positron emission tomography (PET) and observed associations with cardiac MRI abnormalities and elevated inflammatory blood markers.

“In all PET-positive participants, FDG uptake, LVEF, and inflammatory blood markers resolved or improved at follow-up, suggesting that these abnormalities were not related to preexisting cardiovascular disease,” investigators wrote.

The Study

Kate Hanneman, MD, MPH and Paaladinesh Thavendiranathan, MD, University of Toronto, Toronto General Hospital led the prospective cohort study. They examined myocardial metabolic changes early after recovery using PET to associate these changes to abnormalities in cardiac MRI-based function, tissue characterization measures, and inflammatory blood markers.

From November 2020 - June 2021, adult patients (≥18 years) with a positive SARS-CoV-2 test were invited for cardiac PET/MRI and blood biomarker evaluation within 3 months following a positive test. Exclusions were defined as contraindications to PET/MRI, such as impaired kidney function and claustrophobia.

The exposure of interest was defined as myocardial inflammation determined by focal fluorodeoxyglucose (FDG) uptake on PET. Investigators collected data on demographic characteristics, cardiac and inflammatory blood markers, and fasting combined cardiac 18-F-FDG PET/MRI imaging.

Additionally, all patients with focal FDG uptake at baseline then returned for repeated PET/MRI and blood marker assessment 2 months later.

Findings

Invitations were sent to 1263 patients recently recovered from COVID-19 and 47 patients voluntarily joined the cohort, of which 24 (51%) were female and had a mean age of 43 years. Most patients (n = 40) recovered at home during acute infection, with 4 (9%) admitted to the ward and 3 (6%) admitted to the intensive care unit.

The findings showed PET/MRI was performed at a mean of 67 days following COVID-19 diagnosis. Further, FDG uptake on PET was positive in 8 participants (17%) with a focal uptake pattern consistent with myocardial infarction,

In comparison to those without FDG uptake on cardiac MRI, those with focal FDG uptake had significantly higher regional T2, T1, and extracellular volume (ECV). Additionally, they had higher prevalence of gadolinium enhancement (6 of 8, 75% versus 9 of 39, 23%; P = .009), lower left ventricular ejection fraction (mean, 55% versus 62%; P <.001), worse global longitudinal and circumferential strain (mean, -16% versus -17%; P = .02 and -18% versus -20%; P = .047, respectively).

With regards to blood biomarkers, higher systemic inflammatory blood markers including interleukin 6, interleukin 8, and high-sensitivity C-reactive protein were higher in participants with focal FDG uptake compared to those without.

During the follow-up period, PET/MRI and inflammatory blood markers were shown to be resolved or improved at a mean of 52 days after baseline PET/MRI.

The study, “Combined Cardiac Fluorodeoxyglucose–Positron Emission Tomography/ Magnetic Resonance Imaging Assessment of Myocardial Injury in Patients Who Recently Recovered From COVID-19,” was published in JAMA Cardiology.