Key result
Patients with suspected mRNA-vaccine associated myocarditis had a lower prevalence of non-ischemic LGE (6% vs 22%, p=0.04) but more abnormal T1/T2 mapping (45% vs 18%, p=0.010) than pre-COVID cases.
Why the study?
Case series suggested an increased risk of myocarditis after mRNA-based COVID vaccination, motivating an investigation of CMR findings in these patients.
Do CMR findings differ between patients with suspected mRNA-vaccine associated myocarditis and those with suspected myocarditis in the pre-COVID era?
Observational (n=168)
No
Do CMR findings differ between patients with suspected mRNA-vaccine associated myocarditis and those with suspected myocarditis in the pre-COVID era?
Absolute Event Rate: 6% vs 22%
p-value: p=0.04
Patients with suspected mRNA-vaccine associated myocarditis show less LGE but more abnormal T1/T2 mapping on CMR compared to pre-COVID myocarditis referrals, suggesting subtle myocardial damage.
May warrant cautious CMR interpretation in suspected vaccine-myocarditis; leaves open distinct phenotypes and need for prospective outcome studies.
Background: Vaccination is considered the key to overcome the COVID pandemic. For the first time mRNA-based vaccinations are used in humans. Case series suggested an increased risk of myocarditis after vaccination. This study sought to describe CMR findings in patients with suspected mRNA-vaccine associated myocarditis. Methods: A total of 33 consecutive patients referred for CMR work-up of suspected myocarditis associated with mRNA-based vaccination were included. A historical cohort of 135 consecutive patients referred for suspected myocarditis in the pre-COVID era served as control group. All patients underwent multi-parametric CMR including CINE and late gadolinium enhancement (LGE) imaging as well as parametric T1/T2 mapping of the left ventricular myocardium. Results: Patients referred for suspected vaccination-related myocarditis were more often female (55 % vs 32 %, p = 0.015) and demonstrated smaller LV dimensions as well as a better LV function compared to patients of the control group. CMR revealed a lower prevalence of non-ischemic LGE in patients with suspected vaccination-myocarditis (6 % vs 22 %, p = 0.04). However, among patients without LGE we observed a higher prevalence of an abnormal T1/T2 mapping result in patients with suspected vaccination-myocarditis compared to the control group (45 % vs 18 %, p = 0.010). Conclusion: In this small single-centre study, compared to myocarditis referrals in the pre-COVID era, patients currently referred for CMR work-up of suspected mRNA-vaccination-associated myocarditis demonstrated lower prevalence of LGE but higher prevalence of abnormal T1/T2 mapping. These hypothesis-generating observations may point towards a rather subtle myocardial damage and support the routine use of T1/T2 mapping in this indication.
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Seitz et al. (2022) conducted an observational in suspected myocarditis (n=168). mRNA-based COVID vaccination vs. pre-COVID era (no vaccination) was evaluated on prevalence of non-ischemic LGE (p=0.04). Patients with suspected mRNA-vaccine associated myocarditis had a lower prevalence of non-ischemic LGE (6% vs 22%, p=0.04) but more abnormal T1/T2 mapping (45% vs 18%, p=0.010) than pre-COVID cases.
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