Cardiopulmonary Exercise Testing in Children and Young Adolescents after a Multisystem Inflammatory Syndrome: Physical Deconditioning or Residual Pathology?

Multisystem inflammatory syndrome in children (MIS-C) is a serious health condition that imposes a long-term follow-up. The purpose of our pilot study is to evaluate the usefulness of the cardiopulmonary stress test (CPET) in the follow-up after MIS-C. All patients admitted for MIS-C in our hospital in the 12 months preceding the date of observation were considered for inclusion in the study. Pre-existing cardio-respiratory diseases and/or the lack of collaboration were the exclusion criteria. At enrolment, each subject passed a cardiological examination, rest ECG, echocardiogram, 24 h Holter-ECG, blood tests, and a CPET complete of spirometry. A total of 20 patients met the inclusion criteria (11.76 ± 3.29 years, 13 male). In contrast to the normality of all second-level investigations, CPET showed lower-than-expected peakVO(2) and peak-oxygen-pulse values (50% of cases) and higher-than-expected VE/VCO(2-)slope values (95% of cases). A statistically significant inverse correlation was observed between P-reactive-protein values at admission and peakVO(2)/kg values (p = 0.034), uric acid values at admission, and peakVO(2) (p = 0.011) or peak-oxygen-pulse expressed as a percentage of predicted (p = 0.021), NT-proBNP values at admission and peakVO(2) expressed as a percentage of predicted (p = 0.046). After MIS-C (4–12 months) relevant anomalies can be observed at CPET, which can be a valuable tool in the follow-up after this condition.