Pediatric Cardiology Fellow University of Tennessee Health Science Center Cordova, Tennessee, United States
Abstract: Introduction and
Objective: Multisystem inflammatory disease in childhood (MIS-C) is a novel pediatric syndrome occurring after a COVID-19 infection that causes systemic injury. This damage includes myocardial inflammation and vasoplegia with potential life-threatening hemodynamic compromise requiring ECMO support. Myocarditis is a salient feature of MIS-C and given the inflammatory mechanism of myocardial injury, the pathophysiology is comparable to other forms of infectious and non-infectious myocarditis. Literature on the use and outcomes of ECMO support in pediatric MIS-C patients is scant due to the relative novelty of the disease process. The aim of this study is to characterize the population needing ECMO and compare the characteristics and outcomes of MIS-C and non-MIS-C myocarditis in pediatric patients requiring ECMO support.
Methods: Observational retrospective cohort study in children aged 0 to 18 years with MIS-C and non-MIS-C myocarditis supported on ECMO from January 1, 2020 to December 31, 2021, from the ELSO Registry database. Primary outcome was survival to hospital discharge. Secondary outcomes were ECMO duration, mechanical ventilation duration, length of stay, and requirement of heart transplantation or ventricular assist device for decannulation. Distribution of all variables between both the groups have been compared using chi-square statistics for categorical variables and for the means of the continuous variables, t-test was used
Results: The ELSO Registry reported 310 pediatric ECMO patients with diagnosis of MIS-C (n=174, 56.1%) and non-MIS-C myocarditis (n=136, 43.9%). Median age and weight of the cohort were 7.1 years (IQR 0.5-14.9) and 34.7 kilograms (IQR 8.45-72.3). MIS-C patients were significantly older (10.7 vs 2.15 years, p < 0.0001). Veno-arterial support was the most frequent (78.1%) and cannulation via extracorporeal cardiopulmonary resuscitation occurred in 11.9% of patients. MIS-C patients required significantly more veno-venous support (38% vs 0.7%, p < 0.0001), likely due to higher rates of acute respiratory distress syndrome (45% vs 0%, p < 0.0001) and pneumonia (33.9% vs 0%, p < 0.0001). Patients with MIS-C also had significantly higher rates of septic shock (25% vs 0.8%, p < 0.0001), acute renal failure (28.7% vs 0.8%, p < 0.0001) and received higher rates of intravenous immunoglobulins (41% vs 2%, p < 0.0001). Median ECMO duration was significantly higher in MIS-C patients (182.5 hours vs 117 hours, p < 0.0001). No statistical difference was found in survival to hospital discharge between groups (67.2% for MIS-C vs 69.1% for non-MIS-C myocarditis, p 0.725). Length of stay was significantly longer in non-MIS-C myocarditis patients (38 days vs 28 days, p 0.009) with 10.3% of those being transitioned to a ventricular assist device and 2.2% requiring heart transplantation. Table 1 compares characteristics of MIS-C vs. non-MIS-C myocarditis patients.
Conclusions: Outcomes of children with MIS-C requiring ECMO support are similar to those of non-MIS-C myocarditis despite the higher infectious, multiorgan dysfunction and respiratory complications accompanying COVID-19 infections. Prospective studies on the use of ECMO support in MIS-C patients may improve outcomes in this pediatric population.
