Beyond the Acute Phase: Long-Term Impact of COVID-19 on Functional Capacity and Prothrombotic Risk-A Pilot Study.

Background and Objectives : Assessment of the prothrombotic, proinflammatory, and functional status of a cohort of COVID-19 patients at least two years after the acute infection to identify parameters with potential therapeutic and prognostic value. Materials and Methods : We conducted a retrospective, descriptive study that included 117 consecutive patients admitted to Iasi Pulmonary Rehabilitation Clinic for reassessment and a rehabilitation program at least two years after a COVID-19 infection. The cohort was divided into two groups based on the presence ( n = 49) or absence ( n = 68) of pulmonary fibrosis, documented through high-resolution computer tomography. Results : The cohort comprises 117 patients, 69.23% females, with a mean age of 65.74 ± 10.19 years and abnormal body mass index (31.42 ± 5.71 kg/m 2 ). Patients with pulmonary fibrosis have significantly higher levels of C-reactive protein (CRP) ( p < 0.05), WBC (7.45 ± 7.86/mm 3 vs. 9.18 ± 17.24/mm 3 , p = 0.053), neutrophils (4.68 ± 7.88/mm 3 vs. 9.07 ± 17.44/mm 3 , p < 0.05), mean platelet volume (MPV) (7.22 ± 0.93 vs. 10.25 ± 0.86 fL, p < 0.05), lactate dehydrogenase ( p < 0.05), and D-dimers ( p < 0.05), but not ferritin ( p = 0.470), reflecting the chronic proinflammatory and prothrombotic status. Additionally, patients with associated pulmonary fibrosis had a higher mean heart rate ( p < 0.05) and corrected QT interval ( p < 0.05). D-dimers were strongly and negatively correlated with diffusion capacity corrected for hemoglobin (DLCO corr), and ROC analysis showed that the persistence of high D-dimers values is a predictor for low DLCO values (ROC analysis: area under the curve of 0.772, p < 0.001). The results of pulmonary function tests (spirometry, body plethysmography) and the 6-minute walk test demonstrated no significant difference between groups, without notable impairment within either group. Conclusions: Patients with COVID-19-related pulmonary fibrosis have a persistent long-term proinflammatory, prothrombotic status, despite the functional recovery. The persistence of elevated D-dimer levels could emerge as a predictive factor associated with impaired DLCO.