Assessing medium term cardiac outcomes in children with multi-system inflammatory syndrome

Background and Aim: Multi-system inflammatory syndrome in chil-dren (MIS-C) causes widespread systemic inflammation including a pancarditis in the weeks following a COVID infection. Further coronavirus surges appear inevitable and with vaccination rates lower in young people an understanding of the medium-term car-diac impacts of this condition is important for planning further treatment and understanding the impacts on their health. Method(s): A retrospective single-center study of 67 consecutive patients with MIS-C was performed. Three time points were determined as the point of worst cardiac dysfunction during the acute admission, then at intervals of 6-8 weeks and 6-8 months. Echocardiographic findings were used to evaluate both 2D and 3D measures of cardiac function. Coronary artery measurements were recorded. Corresponding serial ECG findings were evaluated. Result(s): The worst cardiac function arose 6.8 +/- 2.4 days after the onset of fever. The mean M mode-derived FS was 30.9 +/- 8.1% during the acute phase. The mean 3D left ventricle (LV) ejection fraction (EF) was borderline at 50.5 +/- 9.8%. A pancarditis was typ-ically present: 46.3% showed cardiac impairment;31.3% had some pericardial effusion;26.8% had moderate (or worse) valvar regur-gitation and;26.8% had coronary dilatation. Cardiac function returned to normal in all patients by 6-8 weeks (mean 3D LV EF 61.3 +/- 4.4%, plt;0.001 compared to admission). Coronary dila-tation normalized in all but one patient who initially developed large aneurysms at presentation;these continued 6 months later. ECG findings mainly featured T-wave changes resolving at fol-low-up. There were a small number of adverse events: need for ECMO (2), death as an ECMO-related complication (1), suben-docardial infarction (1), LV thrombus formation (1). Conclusion(s): MIS-C causes a pancarditis with decreased cardiac function and almost a quarter of patients showing coronary changes. In most, discharge from long-term follow-up can be con-sidered as full cardiac recovery is expected by 8 weeks. The excep-tion includes patients with medium sized aneurysms or greater or those with more of a Kawasaki disease phenotype as these require on-going surveillance for persistence of coronary changes.

Successful resolution of left ventricular thrombuses in a patient with MIS-C

Background and Aim: A 15 year old young man with symptoms and signs consistent with MIS-C was admitted to the Intensive Care Unit for inotropic support as he was exhibiting signs of cardiogenic shock. He was previously fit and healthy and he had been exposed to Covid 19 confirmed cases 6-8 weeks prior to becoming unwell. Method(s): The patient received IVIG and steroids as an immuno-modulating regime. On the admission echocardiogram there was a structurally normal heart with large LV thrombuses. The D-Dimers were extremely elevated on admission and the patient received therapeutic heparin infusion. Other prothrombotic causes were excluded. Result(s): The surveillance echocardiogram 24h post admission showed resolution of the thrombuses. The patient never exhibited any signs or symptoms of cardiac ischaemia on the electrocardio-gram or regional wall motion abnormality on the echocardiogram or neurologic impairment and the brain MRI-MRA one week post admission was normal. The patient was discharged home 5 days post admission and on follow ups up to a year after the acute phase remains very well physically and clinically. Conclusion(s): Thromboembolic events are frequently described in COVID-19 patients and in some patients with MIS-C and are the consequence of a hyperinflammatory response and endothelial dysfunction. There might be a potential role of an antiphospholi-pid syndrome secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection as has been proposed. An increase in D-dimer level has been shown to be associated with thromboembolic events, including arterial thrombosis especially in the older population and should be investigated promptly. With the appropriate immunomodulation and antithrombotic treat-ment adverse events are prevented. More studies to assess endothelial function and its role in the MIS-C prothrombotic state are necessary.

Cardiac dyssynchrony in patients with Paediatric Inflammatory Multisystem Syndrome Temporarily associated with SARS-CoV-2 (PIMS-TS)

Introduction: Paediatric Inflammatory Multisystem Syndrome Temporarily associated with SARS-CoV-2 (PIMS-TS) is commonly associated with cardiovascular compromise. We have previously described the time course and magnitude of left ventricular (LV) systolic dysfunction in children and young adults with PIMSTS. However, it remains unknown if this inflammatory process can cause LV dyssynchrony. We aim to establish whether paediatric patients with PIMS TS develop LV dyssynchrony as assessed by echocardiography. Methods: Comprehensive transthoracic echocardiography in 10 PIMS-TS patients was performed during the acute stage of the initial illness when LV systolic function (3D Ejection Fraction (EF)) was worst and then again at six months post PIMS-TS. At both time points, we compared: 3D EF, LV fractional shortening (FS) and global longitudinal strain (GLS). Intraventricular LV dyssynchrony was assessed byMmode, PW tissue Doppler Velocities (TDI), 2-D speckle tracking and 3D echocardiography, while the interventricular dyssynchrony was also assessed by TDI at both time points. Results: Any improvement in 3D-LV EF at six months post illness (57.8±5.5 %) vs acute phase (51.8± 9.9%) was not statistically significant (p=0.166), whereas the LV FS (29.9± 9.5% vs 36.5± 12.5%, p=0.043) and GLS (-13.8±1.9% vs -18.6±3.1%, p=0.005) were significantly lower during the acute phase of the illness compared to six months later. Regarding dyssynchrony, none of the measures differed at follow up compared with acute phase;the septal to posterior wall motion delay assessed by Mmode (46.1±2.7msec vs 38.6±2.1msec, p=0.417), the basal septal to basal lateral peak velocity delay assessed by TDI (23.2±1.9.msec vs 24±1.9msec, p=0.930), the 2D speckle tracking-derived strain delay index was 1.1±1.2% at the time of the worst LV systolic performance and 0.62±0.26% at 6 months in the recovery period (p=0.219). The 3D echocardiography demonstrated that the 3D systolic dyssynchrony index (SDI) remained similar throughout the follow up period (3.04±1.23% at baseline vs 3.22±1.25% at 6 months, p=0.466). Conclusions: Despite the fact that in patients with PIMS TS cardiac involvement show a decline on LV systolic performance, this does not appear to be associated with LV dyssynchrony as assessed by echocardiography. We recommend larger patient cohort studies to investigate this further.

Long term non-invasive endothelial function assessment in patients with paediatric inflammatory multisystem syndrome temporarily associated with Covid 19 (PIMS TS)

Introduction: Patients with PIMS-TS present with features of vasculitis (bright coronary arteries and diffuse coronary ectasia on transthoracic echocardiography) and prothrombotic features (e.g. elevated D Dimers) indicating involvement of the endothelial layer in the inflammatory process. Impairment in endothelial function may contribute to the acute but also to possible long-term consequences in patients with PIMSTS. The aim of this pilot study is to assess non-invasively the endothelial (dys)function using reactive hyperemic peripheral arterial tonometry (RH-PAT) 6 months after the acute inflammatory phase. Methods: Ten patients with previous diagnosis of PIMS-TS were compared to age-matched controls. The endothelial function was assessed using the EndoPAT device which provides the reactive hyperemic index (RHI) of endothelial function in a 15-min test. Cardiac function indices by means of LV fractional shortening (FS) was also assessed. Results: There were no significant differences regarding age (11.2 ± 3.0 vs 13.6 ± 2.4, p = 0.063), height, weight and body surface area, (BSA: 1.49 ± 0.36 vs 1.52 ± 0.25, p = 0.856) in patients with previous diagnosis of PIMS-TS and controls respectively. The two groups also had similar LV systolic function assessed by FS (36.3 ± 9.1% vs 36.7 ± 7.1%, p = 0.922). The RHI in the PIMS TS group was similar to the control group (1.65 ± 0.43 vs 1.81 ± 0.60, p = 0.533 respectively). Conclusions. Patients with PIMS-TS who may present with features of vasculitis during the acute phase, do not show evidence of endothelial dysfunction during the long term follow-up, suggesting resolution. Further studies are required to accurately determine the endothelial (dys)function during the acute phase of the inflammatory syndrome and course.