You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

We evaluated vascular dysfunction with the single passive leg movement test (sPLM) in 22 frail elderly patients at 84 + 31 days after hospitalization for COVID-19 pneumonia, compared to 22 age-, sex- and comorbidity-matched controls (CTRL). At rest, all COVID-19 patients were in stable clinical condition without severe comorbidities. Patients (aged 72 +/- 6 years, 73% male) had moderate disability (Barthel index score 77 +/- 26), hypoxemia and normocapnia at arterial blood gas analysis and mild pulmonary restriction at spirometry. Values of circulating markers of inflammation (C-reactive protein: CRP; erythrocyte sedimentation rate: ESR) and coagulation (D-dimer) were: 27.13 +/- 37.52 mg/dL, 64.24 +/- 32.37 mm/1 h and 1043 +/- 729 ng/mL, respectively. At rest, femoral artery diameter was similar in COVID-19 and CTRL (p = 0.16). On the contrary, COVID-19 infection deeply impacted blood velocity (p = 0.001) and femoral blood flow (p < 0.0001). After sPLM, peak femoral blood flow was dramatically reduced in COVID-19 compared to CTRL (p = 0.001), as was blood flow peak (p = 0.05) and the area under the curve (p < 0.0001). This altered vascular responsiveness could be one of the unknown components of long COVID-19 syndrome leading to fatigue, changes in muscle metabolism and fibers' composition, exercise intolerance and increased cardiovascular risk. Impact of specific treatments, such as exercise training, dietary supplements or drugs, should be evaluated.
["Treatment", "Mechanism", "Diagnosis"]