Myocarditis is rare in COVID-19 autopsies: cardiovascular findings across 277 postmortem examinations

Abstract

The COVID-19 pandemic, the result of severe acute respiratory syndrome (SARS)-CoV-2, is a major cause of worldwide mortality with a significant cardiovascular component. While a number of different cardiovascular histopathologies have been reported at postmortem examination, their incidence is unknown, due to limited numbers of cases in any given study. A literature review was performed identifying 277 autopsied hearts across 22 separate publications of COVID-19 positive patients. The median age of the autopsy cohort was 75 and 97.6% had one or more comorbidities. Initial review of the data indicate that myocarditis was present in 20 hearts (7.2%); however, closer examination of additional reported information revealed that most cases were likely not functionally significant and the true prevalence of myocarditis is likely much lower (<2%). At least one acute, potentially COVID-19-related cardiovascular histopathologic finding, such as macro or microvascular thrombi, inflammation, or intraluminal megakaryocytes, was reported in 47.8% of cases. Significant differences in reporting of histopathologic findings occurred between studies indicating strong biases in observations and the need for more consistency in reporting. In conclusion, across 277 cases, COVID-19-related cardiac histopathological findings, are common, while myocarditis is rare.

Keywords: COVID-19; SARS-CoV-2; autopsy; heart; inflammation; myocarditis.

Fig. 1

Autopsy cohort information. (A) Relative number of the 277 autopsy cases from each country (the distribution of cases from a consortium could not be determined, but included the Netherlands, Italy and USA). (B) The presence of intravascular megakaryocytes are only described in 2 cases. (C) Although myocarditis was diagnosed in multiple studies, the overall prevalence was significantly skewed due to 12 reports in one study.