In-hospital COVID-19 infection echocardiographic analysis: a Brazilian, tertiary single-centre experience

The study comprised 111 of 154 consecutive adult (> 18 years old) symptomatic patients admitted from March to August 2020 to Hospital Israelita Albert Einstein, São Paulo, Brazil, with a positive diagnosis of COVID-19 (positive reverse transcription-polymerase chain reaction assay). Among the 154 patients, 43/154 (27.8%) patients were not included in the investigation because of poor quality of information. We performed complete transthoracic echocardiography and chest thoracic tomography, collected laboratory findings (biomarkers), considered the demographic data, comorbidities and clinical in-hospital events and related the findings to the composite endpoint of mortality, pulmonary thromboembolism or renal failure that occurred during hospitalization Echocardiographic examinations and thoracic computed tomography were performed following the request of the attending physician responsible for the patient, based on the patient’s clinical needs. Thoracic involvement of the parenchyma was considered as follows: > 25%, 25–50, and > 50%.

Acute renal failure was defined as any of the following: 1- Increase in serum Creatinine ≥0.3 mg/dL (≥26.5 μmol/L) within 48 h or; 2- Increase in serum Creatinine ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days; or 3- Urine volume < 0.5 mL/kg/h for 6 h [25]. This investigation received the approval of the Research Ethics Committee of the Hospital Israelita Albert Einstein (CEP-HIAE) (Institutional Review Board, Comissão Nacional de Ética em Pesquisa No 3.960.096). All patients or a person legally responsible signed the informed consent forms for the echocardiographic examination.

The patients underwent complete transthoracic echocardiography under the request of the attending physician responsible for the patient, based on clinical needs. Echocardiography was performed following current international recommendations for COVID-19 echocardiographic performance [26]. Thus, to perform the echocardiographic examinations, personal protection equipment, including airborne protection (N-95 masks), gloves, head covers, face shield protection and fluid-resistant gowns were required. The echocardiographic examinations were performed in a standard manner employing the same equipment (Epiq 7; Philips Medical Systems, Bothell, WA, USA) by cardiologists with complete echocardiographic training. The acquisition of echocardiographic data was from bedside studies performed in COVID-19 intensive care units or internal ward units, with posterior offline analysis in the Echolab section at a workstation employing the software Q lab 13.0 (Philips Medical Systems, Bothell, WA, USA). The echocardiographic examination comprised a two-dimensional echocardiogram with colour Doppler, spectral Doppler and tissue Doppler, as well as longitudinal strain measurements derived from speckle tracking concerning the left and right ventricles. Imaging acquisition comprised longitudinal parasternal projections of the left, transverse and apical 2, 3 and 4 chambers, following the American Society of Echocardiography standardization [27]. To evaluate the left ventricular volumes and ejection fraction, we employed the Simpson biplane method using an automatic calculation algorithm. Diastolic function was analysed considering the evaluation of the spectral Doppler of the transmitral flow, measurements of the maximum velocities of the E and A waves, E/A ratio and E wave deceleration time, and tissue Doppler traces obtained from the apical four-chamber view, with the Doppler sample in the basal region of the ventricular septum (medial mitral annulus) and lateral mitral annulus. The E/e’ ratio was obtained from the septal and lateral segments of the mitral ring. The pulmonary artery systolic pressure was estimated by the tricuspid reflux. Cardiac valves were analysed using bidimensional echocardiography and Doppler and Colour Doppler techniques. Global longitudinal left ventricular strain was analysed from the apical planes of four, three and two chambers. To analyse the right ventricle, we evaluated the tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), tissue Doppler (S wave) and longitudinal strain parameters. Longitudinal right ventricular strain was obtained from the apical plane of four chambers for better visualization of the right ventricle.

Images from echocardiographic studies are depicted in Figs. 1 and 2.

Figure 3 depicts the distribution of the echocardiographic findings.

The patients were analysed using qualitative parameters described as absolute and relative frequencies and quantitative parameters (mean, standard deviation, minimum and maximum) [28, 29] The associations between mortality and qualitative characteristics were evaluated using chi-squared test or exact tests (Fisher’s exact test or the likelihood ratio test); quantitative characteristics were compared between mortality or hospital discharge using using Student’s t-test or the Mann-Whitney test according the probability distribution of the variables [27, 28].

The area under the receiver operating (ROC curve) was constructed for echocardiographic parameters related to the prediction of a composite endpoint of mortality, pulmonary thromboembolism or acute renal failure of COVID-19 in-hospital patients, and odds ratios were calculated by logistic regression for the echocardiographic parameters and composite group of events. Analyses were performed using IBM-SPSS for Windows version 20.0 software, 5% significance level.

This investigations concerning echocardiographic evaluation of in-hospital COVID-19 patients from a single Brazilian tertiary hospital centre, comprising a limited population, could have caused imbalances and bias in the analysis. Therefore, further studies enrolling multiple different hospitals will add important information concerning the role of echocardiography in this infectious scenario.