COVID-19 in an adult with right isomerism and Fontan circulation: Successful management using risk stratification.

Reports regarding coronavirus disease 2019 (COVID-19) with Fontan circulation are limited. Most studies indicate a relatively good clinical outcome in which SARS-CoV-2 infection is abated; however, COVID-19 can still cause severe pneumonia, and some studies report circulatory breakdown associated with acute respiratory distress syndrome in patients with Fontan circulation. We present the case of a 32-year-old Japanese woman with right isomerism and a single right ventricle who had undergone a fenestrated extracardiac total cavopulmonary connection (Fontan operation), atrioventricular valve replacement, and pacemaker implantation. Despite receiving three doses of the severe acute respiratory syndrome coronavirus 2 mRNA vaccine, the patient contracted COVID-19 and presented with pneumonia. Although her symptoms were mild, the patient was classified as high-risk based on the European Society of Cardiology risk stratification guidelines for COVID-19 in patients with adult congenital heart disease and was admitted to the hospital. Initially, the patient received only symptomatic treatment. However, 2 days later, the patient's COVID-19 condition worsened to moderate grade level II (SpO₂ ≤93%, oxygen demand), with SpO₂ dropping from 95% to 88% on room air. Treatment with remdesivir and dexamethasone following Japanese treatment protocols resulted in clinical improvement and discharge without hemodynamic complications. COVID-19 pneumonia risks disrupting Fontan circulation in affected patients. This case illustrates the importance of prompt risk stratification using anatomical and physical evaluation and adherence to treatment guidelines in the management of patients with Fontan circulation and COVID-19.