Echocardiographic characterisation in severe Covid-19 with respiratory failure - an observational study

Objective We aimed to investigate cardiac effects of severe SARS-CoV-2 and the importance of echocardiography-assessment and biomarkers. Methods This is an observational study of the first patients admitted to intensive care due to SARS-CoV-2-respiratory failure. Thirty-four underwent echocardiography of which twenty-five were included, compared to forty-four non-echo patients. Exclusion was based on absence of normofrequent sinus rhythm and/or mechanical respiratory support. Biomarkers were analysed on clinical indication. Results Mortality was higher in the echo-compared to non-echo group (44 % vs. 16%, p<0.05). Right-sided parameters were not under significant strain. Tricuspid valve regurgitation velocity indicated how increased pulmonary pressure was associated with mortality (survivors: 2.51 ± 0.01 m/s vs. non-survivors: 3.06 ± 0.11 m/s, p<0.05), before multiple comparison-correction. Setting cut-off for pulmonary hypertension to 2.8 m/s generated p<0.01 using frequency distribution testing. Cardiac markers, high sensitivity cardiac troponin I and N-terminal pro brain natriuretic peptide, and D-dimer were higher in the echocardiography group. (hs-TnI (ng/L): echo : 133 ± 45 vs. non-echo: 81.3 ± 45, p<0.01; NT-proBNP (ng/L): echo: 2959 ± 573 vs. non-echo: 1641 ± 420, p<0.001; D-dimer (mg/L): echo: 16.1 ± 3.7 vs. non-echo: 6.1 ± 1.5, p<0.01) and non-survivor group (hs-TnI (ng/L): survivors: 59.1 ± 21 vs. non-survivors: 211 ± 105, p<0.0001; NT-proBNP (ng/L): survivors: 1310 ± 314 vs. non-survivors: 4065 ± 740, p<0.0001; D-dimer (mg/L): survivors: 7.2 ± 1.5 vs. non-survivors: 17.1 ± 4.8, p<0.01). Tricuspid regurgitation velocity was positively correlated with cardiac troponin I (r=0.93, r 2 =0.74, p<0.001). Conclusions These results suggest there is no negative effect on cardiac function in critical SARS-CoV-2. Pulmonary pressure appears higher amongst non-survivors indicating pulmonary disease as the driver of mortality. Echocardiography was more commonly performed in the non-survivor group, and cardiac biomarkers as well as D-dimer was higher in the non-survivor group suggesting they carry negative prognostic values. Trial registration number This is an observational study from patients included in “Clinical trials NCT04316884 ” Strength and limitations of this study - The patient cohort is recruited from consecutive patients admitted to the ICU in need of mechanical respiratory support independent of background which makes it relevant to clinical practice. - The echocardiographic image acquisition was carried out by hospital assigned agents on clinical indication, which makes the results applicable in a clinical setting. - Since the image acquisition was carried out on a clinical indication, the results may be skewed towards the false positive if applied to all Covid19 patients.