Cardiopulmonary Exercise Testing Distinguishes between Post-COVID-19 as a Dysfunctional Syndrome and Organ Pathologies.

(1) Background: Dyspnea is one of the most frequent symptoms among post-COVID-19 patients. Cardiopulmonary exercise testing (CPET) is key to a differential diagnosis of dyspnea. This study aimed to describe and classify patterns of cardiopulmonary dysfunction in post-COVID-19 patients, using CPET. (2) Methods: A total of 143 symptomatic post-COVID-19 patients were included in the study. All patients underwent CPET, including oxygen consumption, slope of minute ventilation to CO2 production, and capillary blood gas testing, and were evaluated for signs of limitation by two experienced examiners. In total, 120 patients reached a satisfactory level of exertion and were included in further analyses. (3) Results: Using CPET, cardiovascular diseases such as venous thromboembolism or ischemic and nonischemic heart disease were identified as either cardiac (4.2%) or pulmonary vascular (5.8%) limitations. Some patients also exhibited dysfunctional states, such as deconditioning (15.8%) or pulmonary mechanical limitation (9.2%), mostly resulting from dysfunctional breathing patterns. Most (65%) patients showed no signs of limitation. (4) Conclusions: CPET can identify patients with distinct limitation patterns, and potentially guide further therapy and rehabilitation. Dysfunctional breathing and deconditioning are crucial factors for the evaluation of post-COVID-19 patients, as they can differentiate these dysfunctional syndromes from organic diseases. This highlights the importance of dynamic (as opposed to static) investigations in the post-COVID-19 context.

Symptom burden correlates to impairment of diffusion capacity and exercise intolerance in long COVID patients.

After acute infection with the SARS-CoV-2 virus, a considerable number of patients remains symptomatic with pathological changes in various organ systems. This study aimed to relate the physical and mental burden of symptoms of long COVID patients to the findings of a somatic evaluation. In patients with persistent long COVID symptoms three months after acute infection we assessed physical and mental health status using the SF-36 questionnaire. The cohort was dichotomised by the results (upper two quartiles vs. lower to quartiles) and compared with regard to transthoracic echocardiography, body plethysmography (including diffusion capacity), capillary blood gas analysis and 6-min walk test (6-MWT). From February 22 to September 13, 2021, 463 patients were prospectively examined, of which 367 completed the SF-36 questionnaire. A positive correlation between initial disease severity (need for hospitalization, intensive care medicine) and resulting symptom burden at follow-up could be demonstrated. Patients with impaired subjective physical and mental status were significantly more likely to be women. There was a significant correlation between symptom severity and reduced exercise tolerance in the 6-MWT (495.6 ± 83.7 m vs 549.7 ± 71.6 m, p < 0.001) and diffusion capacity for carbon monoxide (85.6 ± 14.3% of target vs 94.5 ± 14.4, p < 0.001). In long COVID patients, initial disease severity is correlated with symptom burden after at least 3 months of follow-up. Highly symptomatic long COVID patients show impaired diffusion capacity and 6-MWT despite average or mildly affected mechanical lung parameters. It must be further differentiated whether this corresponds to a transient functional impairment or whether it is a matter of defined organ damage.

Long COVID: Distinction between Organ Damage and Deconditioning.

(1) Background: Long COVID syndrome refers to long-term sequelae of the novel viral disease, which occur even in patients with initially mild disease courses. However, there is still little evidence of the actual organic consequences and their frequency, and there is no standardized workup to diagnose long COVID syndrome yet. In this study, we aim to determine the efficiency of a stepwise diagnostic approach for reconvalescent COVID-19 patients with cardiopulmonary symptoms. (2) Methods: The diagnostic workup for long COVID syndrome included three steps. In the first step, the focus was on broad applicability (e.g., blood tests and body plethysmography). In the second step, cardiopulmonary exercise testing (CPET) and cardiac MRI (CMR) were used. The third step was tailored to the individual needs of each patient. The observation period lasted from 22 February to 14 May 2021. (3) Results: We examined 231 patients in our long COVID unit (mean [SD] age, 47.8 [14.9], 132 [57.1%] women). Acute illness occurred a mean (SD) of 121 (77) days previously. Suspicious findings in the first visit were seen in 80 (34.6%) patients, prompting further diagnostics. Thirty-six patients were further examined with CPET and CMR. Of those, 16 (44.4%) had pathological findings. The rest had functional complaints without organ damage ("functional long COVID"). Cardiopulmonary sequelae were found in asymptomatic as well as severe courses of the initial COVID-19 disease. (4) Conclusions: A structured diagnostic pathway for the diagnosis of long COVID syndrome is practicable and rational in terms of resource allocation. With this approach, manifest organ damage can be accurately and comprehensively diagnosed and distinguished from functional complaints.