Discussion
The unequal distribution of race in our study likely reflects the
demographics that our institute caters to. Although there have been
reports that Hispanic and African American patients are
disproportionately more effected and have worse outcomes. Hypertension
and diabetes mellitus were the most common co morbidities in our
patients associated with COVID-19 infection as seen in most of the
previously published literature. Elevated brain natriuretic peptide
(BNP) and cardiac troponin (cTr) have been associated with myocardial
injury and poor outcomes. Inflammatory biomarkers also play an
important role in risk stratification of disease severity and
prognostication. The prevalence of elevated biomarkers in our study was
higher than the 8-12% observed by Lippi et al [2]. This was most
likely the result of selection bias of performing echocardiograms on
the patients suspected to have cardiac injury. Other inflammatory
biomarkers, like LDH , ferritin. and D-dimer suggesting were elevated in
majority of our patients. These markers have been found to be associated
with severe disease, hyper coagulation and increased mortality.
Myocarditis based on elevated troponins and inflammatory markers has
been described previously [1] but no data on echocardiographic
findings in these patients is available. The etiology of left
ventricular dysfunction can be multifactorial in these patients. These
patients can have acute myocardial infarction(AMI) due to plaque rupture
secondary to stress of infection as was seen in one of our patients who
had complete occlusion on the mid left anterior descending artery and
underwent percutaneous intervention. One patient in our study group
developed stress related cardiomyopathy secondary to COVID-19 infection.
He presented as cardiac arrest with minimal troponin elevation,
echocardiogram was typical for takotsubo cardiomyopathy. Other possible
etiologies for poor LV function in these patients could be myocarditis
and prior LV dysfunction. Two echocardiograms were requested to rule LV
thrombus as the patients presented with acute limb ischemia but LV
thrombus was not seen in any patients in our study including these two
patients. The arterial thrombosis in these patients could result from
coagulopathy secondary to disseminated intravascular coagulation,
heparin-induced thrombocytopenia, thrombotic microangiopathy and
antiphospholipid antibodies [3].
We had 2 patients with pulmonary embolism (PE) in our study group,
echocardiogram guided diagnosis in these patients. There is a very high
risk of thromboembolism including pulmonary embolism in patients with
severe COVID-19 infection. Recently published data suggests incidence of
thromboembolism as high 31% critically ill patients, pulmonary embolism
was the most frequent (81%) thromboembolic complication in these
patients [4]. In our study RV thrombus was visualized in one
patient, which was confirmed on computed tomography angiography (CTA)
of the chest, showing diffuse pulmonary embolism. She was treated with
low molecular weight heparin and repeat echocardiogram done 2 weeks
later showed near complete resolution of thrombus. The other patient
with PE who was a 28 year old female with COVID -19 infection and no
other risk factors, presented with severe shortness of breath was found
to have CTA confirmed extensive bilateral pulmonary embolism after her
echocardiogram showed RV dilatation with flattening of IVS. She received
tissue plasminogen activator (tPA) and was eventually discharged home on
apixaban. There is growing consensus that patients with COVID -19
infection have a prothrombotic state and development of microthrombi in
pulmonary vasculature as demonstrated by pathological studies [5],
this most likely could explain the elevated pulmonary pressures and RV
dysfunction in these patients. Emerging evidence suggests that
anticoagulation could help a selected group of patients[6],
echocardiogram may act as an aid to identify these patients. Also
hypoxemia and high positive end expiratory pressure ventilation
requirement in these patients can lead to RV dysfunction and eventually
poor cardiac output. Bedside echocardiogram in critical care units can
help in identifying features of RV dysfunction and help in management of
ventilators to minimize adverse effects on cardiac output.
In conclusion, 2-dimensional echocardiography can be an important
bedside tool in assessment of left and right ventricular function and
hemodynamic status COVID-19 patients. When appropriately chosen for the
correct group of patients echocardiogram can help in navigating
management options and identifying complications.
Table 1 showing echocardiographic and laboratory parameters