Hyperechogenic signal from the pericardium after vaccination against SARS-CoV-2

The full-scale syndrome of pericarditis or subclinical changes in pericardium, as seen during transthoracic echocardiography, are detected in large number of patients with COVID-19 or or those who have recovered from COVID-19, and can persevering for about a year. There is a significant accumulation of reported cases of pericarditis following vaccination against SARS-CoV-2. Questions remain about subclinical pericardial involvement in vaccinated patients. The study is aimed to examine pericardial changes through transthoracic echocardiography in patients vaccinated against SARS-CoV-2, and describe their dynamics and compare the ultrasound views with symptoms and inflammatory changes in blood tests. Methods. Inclusion criteria: The patient’s consent, the intention to be vaccinated against SARS-CoV-2, no confirmation and suspicions about COVID-19 in the past, unchanged pericardium as of Visit 0, as well as no diseases which may cause any changes in the pericardium throughout the time of the study. Exclusion criteria: SARS-CoV-2 infection during the study, refusal or any impossibility to make more as 1 scheduled visit for check-up. Echocardiography was performed according to a standardized protocol at unchanged brightness settings with a focus on the pericardium in dynamics: before the vaccination (Visit 0), within a week after the first dose (Visit 1) and the second dose (Visit 2), and in a month (Visit 3), 2 months (Visit 4), 3 months (Visit 5) and 4 months (Visit 6) after the latest dose of the vaccine. Complete venous blood count with a leucogram and determination of the erythrocyte sedimentation rate was performed at visits 0 and 2. Results. 52 patients completed their participation in the study. Low-intensity changes in the pericardium after the first dose of the vaccine were found in 67% of patients. Ultrasound changes arose as a more enhanced echocardiographic signal in the basal segments of the inferolateral area in 57%, spread up to the basal segment of the anterior lateral area in 13%, the area around the atria in 15%. Pericardial layer separation for 3 and more mm was found in 23%. After the second dose of the vaccine was administered, 74% demonstrated the enhancement of the pericardium, including signs of minor effusion in 20% of patients. The pericardium image got slightly less bright in 4 ± 1 weeks after the second dose: up to the conditional normal state (the visual quality of the pericardium in a specific person as of visit 0) in 2 patients. However, the pericardium remained brighter in 71%, with the minimal effusion in 1 patient. 68% of patients demonstrated the pathological TTE image in the 8th week after the vaccination, with effusion being discovered in 2% of patients. The hyperechogenity of the pericardium was detected in 66% in 12 ± 1 weeks, without effusion being found. The pericardium still remained brighter in 16 ± 1 weeks in 7% of patients than it was before the vaccination. Low-intensity pericardial chest pain is detected only with active questioning and is recorded in up to 8% of cases in the first 4 days after the administration of the 1st and /or 2nd doses of the vaccine, did not correlate with the duration of hyperechogenity, but did- with exudation: r = 0,22 (p = 0,05). Of the analyzed blood parameters, an increase in the percentage of neutrophils by 2.8% was registered after vaccination, the increase in their proportion correlated with the presence of a combined point, including any of the considered echo parameters of the pericardium, at visit 2: r = 0.5, p < 0, 05; in 6% of patients, neutrophils exceeded normal values. Also, after vaccination, the erythrocyte sedimentation rate significantly increased (on average, by 4.2 mm/h), which correlated with the presence of a combined point of pericardial changes (r = 0.6, p < 0.05). The erythrocyte sedimentation rate threshold was exceeded in 12% of the subjects: all of them had a recorded effusion according to echocardiography. The appearance of band forms neutrophils by 1 week after the administration of the 2nd dose of the vaccine was registered in 50% of patients. None of the observed required hospitalization and died. Conclusion. The overwhelming majority of patients demonstrated the TTE phenomenon of the enhanced or effused pericardium as a result of the vaccination. Minimal changes completely disappeared in 4 months. The presence of ultrasound changes in the pericardium correlates with an increase in erythrocyte sedimentation rate and / or the proportion of neutrophils is accompanied by a stab shift in 50% of the analyzes. We believe more aimed research is needed to evaluate systemic effects of virus antigens on the body. Drawing upon the experience of the center, the above TTE changes are much less intense in terms of TTE signs than it happens after contacting a live pathogen. Therefore, it can definitely be more preferable than “natural” immunization due to illness Key words: COVID-19, complications, echocardiography, pericarditis, vaccination