Table 1.
Baseline characteristics
| Variable | Healthy controls | Historical ICU COVID-19 cohort | Long COVID cohort | p value# | p value++ |
|---|---|---|---|---|---|
| Number of participants (n; %) | 15 | 16 | 27 | – | – |
| Female sex (n; %) | 8 (53.3) | 3 (13) | 12 (44.4) | 0.75 | 0.03 |
| Age [years, median (IQR)] | 53 (39–69) | 62 (56–72) | 53 (39–51) | 0.45 | 0.004 |
| BMI [kg/m2, median (IQR)] | 23.7 (22.0–25.2) | 27.3 (23.5–31.5) | 27.1 (23.2–29.1) | 0.17 | 0.74 |
| Hospitalized (n; %) | – | 16 (100) | 15 (55.5) | – | – |
| SOFA score [pts, median (IQR)] | – | 6 (2–13) | – | – | – |
| Vasopressors (n; %) | – | 6 (37.5) | – | – | – |
| Invasive mechanical ventilation (n; %) | – | 14 (87.5) | – | – | – |
| In-hospital mortality (n; %) | – | 6 (26.1) | – | – | – |
| Days after COVID-19 infection | – | 7 (1–17) | 541 (305–569) | – | < 0.001 |
| CCI score [median (IQR)] | 0 | 1 (0–3) | 0 (0) | 0.99 | 0.005 |
| Comorbidities (n; %) | |||||
| Arterial hypertension | 0 | 11 (68.8) | 4 (14.8) | 0.28 | < 0.001 |
| Diabetes mellitus | 0 | 0 | 0 | – | – |
| Chronic respiratory disease | 0 | 3 (18.8) | 2 (7.4) | 0.53 | 0.34 |
| Congestive heart failure | 0 | 6 (37.5) | 0 | 0.99 | 0.001 |
| Rheumatologic disease | 0 | 3 (17.2) | 3 (11.1) | 0.54 | 0.65 |
| Malignancy | 0 | 3 (18.8) | 1 (3.7) | 0.99 | 0.14 |
| Long COVID symptoms (n; %) | |||||
| > 1 Symptoms | – | – | 23 (85.2) | – | – |
| Fatigue/Weakness | – | – | 23 (85.2) | – | – |
| Dyspnea | – | – | 22 (81.5) | – | – |
| Chest discomfort | – | – | 6 (22.2) | – | – |
| Neurocognitive dysfunction | – | – | 4 (14.8) | – | – |
| Persistent cough | – | – | 2 (7.4) | – | – |
| Headache | – | – | 2 (7.4) | – | – |
| Sublingual videomicroscopy [median (IQR)] | |||||
| PBR (µm) | 2.23 (2.02–2.31) | 2.39 (2.13–2.52) | 2.15 (2.03–2.27) | 0.45 | 0.02 |
| Capillary density (10−2 mm/mm2) | 77.89 (66.66–83.27) | 19.88 (12.13–42.08) | 46.43 (39.15–63.49) | < 0.001 | < 0.001 |
| VRBC4–7 µm (µm/sec) | 103 (89.87–112.6) | 82.67 (75.03–95.53) | 114.9 (102.7–134.4) | 0.01 | < 0.001 |
| VRBC≥10 µm (µm/sec) | 100.60 (93.95–110.10) | 85.14 (97.12–69.55) | 124 (119.60–132.20) | < 0.001 | < 0.001 |
| MVHS (points) | 3.87 (3.15–4.87) | 0.92 (0.766–1.85) | 2.72 (2.21–3.01) | 0.002 | < 0.001 |
| Capillary recruitment (%)* | 70 | 17 | 29 | – | – |
Bold indicates the statistically significant p values (p < 0.05)
BMI Body mass index, CBV capillary blood volume, CCI score Charlson Comorbidity Index, COVID-19 Coronavirus disease 2019, CRP C-reactive protein, D capillary diameter, IQR interquartile range, MVHS Microvascular Health Score, PBR Perfused boundary region, PCT Procalcitonin, SOFA score Sequential Organ Failure Assessment score, VRBC red blood cell velocity
*Capillary recruitment was estimated using 1 − slope (VRBC (D ≤ 7 µm), VRBC (D ≥ 10 µm)) in a per group analysis
#p values were calculated between healthy controls and long COVID patients
++p values were calculated between historical COVID-19 cohort and long COVID patients