Abstract
Background and aims: Myocardial injury is frequent in patients
hospitalized with Sars-COV-2 infection and portents a worse prognosis,
but the cause of myocardial injury is uncertain. Coronary microvascular
dysfunction (CMD) has been hypothesized as a possible explanation, but
direct evidence demonstrating CMD in COVID-19 patients is missing. In
the present study, we aimed to investigate whether CMD is present in
hospitalized COVID-19 patients, and to understand whether there is a
relationship between biomarkers of myocardial injury, myocardial strain
and inflammation and CMD in COVID-19 patients. Methods: 39
patients that were hospitalized with COVID-19 and 40 control subjects
were included to the present study. Biomarkers for myocardial injury,
myocardial strain, inflammation and fibrin turnover were obtained at
admission. A comprehensive echocardiographic examination, including
measurement of coronary flow velocity reserve (CFVR), were done after
the patient was stabilized. Results: Patients with COVID-19 infection
had a lower hyperemic coronary flow velocity, resulting in a
significantly lower CFVR (2.0±0.3 vs. 2.4±0.5, p<0.001).
Patients with severe COVID-19 also had a lower CFVR compared to those
with moderate COVID-19 (1.8±0.2 vs. 2.2±0.2, p<0.001) due to
an increase in basal flow velocity (30.0±6.2 vs. 26.0±4.8, p=0.04). CFVR
correlated with troponin (p=0.003,r:-0.470), B-type natriuretic peptide
(p<0.001,r:-0.580), C-reactive protein
(p<0.001,r:-0.369), interleukin-6 (p<0.001,r:-0.597)
and d-dimer (p<0.001,r:-0.561), with the three latter
biomarkers having the highest area-under-curve for predicting CMD.
Conclusions: CMD is common in patients with COVID-19, and is related
with the severity of the infection. CMD may also explain the “cryptic”
myocardial injury seen in patients with severe COVID-19 infection.