Conclusions
Patients with moderate to severe COVID-19 have a reduced hyperemic coronary flow and CFVR indicating presence of CMD. The degree of CMD correlates with biomarkers of inflammation, fibrin turnover, myocardial injury and myocyte stretch, though it remains to be determined whether these associations represent causal relationships between inflammation, thrombosis, microvascular dysfunction, and finally myocardial injury. Further work is needed to understand the clinical importance of these findings, as well as therapeutic approaches to prevent or treat CMD in COVID-19 patients.