부산대학교 도서관

Introduction: The pathophysiologic mechanisms underlying persistent post-COVID cardiorespiratory symptoms remain understudied, despite the significant worldwide prevalence. Invasive cardiopulmonary exercise testing (iCPET) is a novel investigation that can inform our understanding of underlying hemodynamic abnormalities.Research Question: What is the prevalence of dysfunctional breathing (DB) and preload insufficiency (PI) in post-COVID patients who undergo iCPET?Methods: We studied hemodynamic characteristics in a cohort of 52 post-COVID patients who underwent iCPET in a sitting bicycle. The protocol augments CPET with continuous hemodynamic and laboratory data from pulmonary artery catheterization and arterial line. PI is defined as abnormally low right atrial pressure during exercise and reduced peak cardiac output percentage of predicted. DB is characterized by exercise-induced oscillatory ventilation.Results: The study cohort had a mean age of 40.8 years, and 36 of the 52 patients (69.2%) were female. iCPET revealed the prevalence of only DB as 15.4%, only PI as 34.6%, both DB and PI as 34.6%, and neither DB nor PI as 15.4%. These 4 sub-groups were subsequently compared for analysis. Notably, the cardiac output percentage of predicted at peak exercise was significantly different between the 4 groups (95.4%, 81.2%, 85.1%, 102.9%; p=0.007). The differential between baseline (sitting) and peak (maximal exercise) right atrial pressure was also significantly different between the 4 groups (0.00, 0.056, 0.333, 4.875; p=0.026). Our study suggests that PI and DB are common entities noted in symptomatic post-COVID patients, and may co-occur.Conclusion: This study is a first step towards understanding the altered hemodynamics that drive common symptoms in post-COVID patients. iCPET yields physiologic mechanistic information that could inform targeted interventions.