Sustained Impairment in Cardiopulmonary Exercise Capacity Testing in Patients after COVID-19: A Single Center Experience

Abstract

Background. Following COVID-19, patients often present with ongoing symptoms comparable to chronic fatigue and subjective deterioration of exercise capacity (EC), which has been recently described as postacute COVID-19 syndrome. Objective. To objectify the reduced EC after COVID-19 and to evaluate for pathologic limitations. Methods. Thirty patients with subjective limitation of EC performed cardiopulmonary exercise testing (CPET). If objectively limited in EC or deteriorated in oxygen pulse, we offered cardiac stress magnetic resonance imaging (MRI) and a follow-up CPET. Results. Eighteen male and 12 female patients were included. Limited relative EC was detected in 11/30 (36.7%) patients. Limitation correlated with reduced body weight-indexed peak oxygen (O2) uptake (peakV̇O2/kg) (mean 74.7 (±7.1) % vs. 103.6 (±14.9) %, p < 0.001 ). Reduced peakV̇O2/kg was found in 18/30 (60.0%) patients with limited EC. Patients with reduced EC widely presented an impaired maximum O2 pulse (75.7% (±5.6) vs. 106.8% (±13.9), p < 0.001 ). Abnormal gas exchange was absent in all limited EC patients. Moreover, no patient showed signs of reduced pulmonary perfusion. Using cardiac MRI, diminished biventricular ejection fraction was ruled out in 16 patients as a possible cause for reduced O2 pulse. Despite noncontrolled training exercises, follow-up CPET did not reveal any exercise improvements. Conclusions. Deterioration of EC was not associated with ventilatory or pulmonary vascular limitation. Exercise limitation was related to both reduced O2 pulse and peakV̇O2/kg, which, however, did not correlate with the initial severity of COVID-19. We hypothesize that impaired microcirculation or limited peripheral O2 utilization might be causative for prolonged deterioration of EC following acute COVID-19 infection.

Cardiopulmonary exercise testing to evaluate post-acute sequelae of COVID-19 (“Long COVID”): a systematic review and meta-analysis

“…30,33 Five studies reported chronotropic incompetence to be a major cause of reduced exercise capacity, 25,30,44,63,64 and most studies reported a lower peak heart rate among individuals with reduced exercise capacity. One study each specifically reported pulmonary fibrosis, 65 pulmonary vascular limitation, 66 impaired microcirculation, 61 endothelial dysfunction, 67 dysautonomia, 64 and loss of mechanical efficiency 28 as the primary etiology of reduced exercise capacity. Despite concerns about pulmonary thromboembolism during acute infection, pulmonary vascular limitations were uncommon.…”

“…29 Evers found no significant changes in peak VO2 over 3 months among 23 individuals with reduced exercise capacity who underwent repeat CPET. 61 Moulson found that peak VO2 improved among young symptomatic athletes 5 months after index study. 32 Improvement correlated with symptom resolution, but peak heart rate was unexpectedly reduced.…”

“…50,[52][53][54][55][56][57] Muscular/peripheral oxygen extraction abnormalities were also commonly reported. 26,29,[58][59][60][61][62] Using invasive CPET, Singh found reduced peripheral oxygen extraction, and others reported alterations in metabolism and lactate production. 27,58,60 Cardiac limitations were uncommon, but Mancini reported attenuations in preload augmentation 52 and Brown and Szekely reported reduced stroke volume augmentation.…”

Effect of Oral Nirmatrelvir on Long COVID Symptoms: 4 Cases and Rationale for Systematic Studies

“…In this case, the participant already has objective findings (reduced peak VO2 and chronotropic incompetence) consistent with PASC, which may contribute to reduced exercise capacity and have been shown to persist in some cases. [5][6][7] This suggests that although a short course of early antiviral therapy is adequate to prevent severe acute disease in high-risk patients, [8] it may be insufficient to prevent the development of Long COVID, and those experiencing rebound symptoms could remain at risk. A related hypothesis is that SARS-CoV-2 may persist for weeks to months in some individuals, causing inflammation, local tissue damage, and end-organ disease.…”

Return to exercise post-COVID-19 infection: A pragmatic approach in mid-2022

“…However, it is possible to have a reduced exercise capacity as part of “Long COVID” even in the presence of a completely normal cardiac workup. 26 …”