TABLE 3.
Additional measures of cardiac, vascular, muscle and autonomic function and hemoglobin status for participants with long COVID.
| Additional measures in participants with long COVID | |||||
|---|---|---|---|---|---|
| Mean ± SD median [IQR] or n (%) | Normal range or cut‐off for normal | Reference | Participants outside of normative values n [% (95% CI)] | p‐value | |
| Cardiopulmonary exercise test | (n = 28) | ||||
| Extrapolated V̇O2 max [mL/kg/min] | 30 ± 7 | a | Wasserman et al. (2005) | 9 [32% (18, 51%)] | <0.001 |
| OUES [mL/min] | 1877 ± 495 | <1500 | Wasserman et al. (2005) | 8 [31% (15, 47%)] | <0.001 |
| V̇E/V̇CO2 slope | 28 ± 3 | >30 | Nayor et al. (2020) | 4 [14% (6, 32%)] | 0.049 |
| V̇O2/WR [mL/min/W] | 8.6 ± 1.4 | <8.5 | Wasserman et al. (1999) | 13 [46% (30, 64%)] | <0.001 |
| Breathing reserve [L/min] | 72 ± 27 | <15 | American Thoracic Society and American College of Chest Physicians (ACCP) (2003) | 0 [0%] | ‐ |
| Lung function | (n = 32) | ||||
| Abnormal spirometry | ‐ | <−1.64 | Haynes (2018) | 10 [31% (18, 49%)] | <0.001 |
| Restrictive spirometry pattern | ‐ |
FVC < −1.64 & FEV1/FVC > −1.64 |
Haynes (2018) | 5 [16% (7, 32%)] | 0.020 |
| Obstructive spirometry pattern | ‐ | FEV1/FVC < −1.64 | Haynes (2018) | 2 [6% (2, 20%)] | 0.480 |
| Reduced FEV1 only | ‐ |
FEV1 < −1.64 & FVC > −1.64 & FEV1/FVC > −1.64 |
Haynes (2018) | 3 [9% (3, 24%)] | 0.214 |
| Echocardiography | (n = 32) | ||||
| Systolic function | |||||
| 3D LVEF [%] | 66 ± 8 | >55 | Lang et al. (2015) | 0 [0%] | ‐ |
| 3D GLS [%] | −24.6 [4.2] | <−14 | Lang et al. (2015) | 0 [0%] | ‐ |
| Diastolic function | |||||
| Average E/e′ | 7.5 [2.6] | ≤14 | Nagueh et al. (2016) | 1 [3% (1, 16%)] | 0.806 |
| Septal e′ velocity [cm/s] | 9.0 [2.4] | ≥7 | Nagueh et al. (2016) | 8 [25% (13, 42%)] | <0.001 |
| Lateral e′ velocity [cm/s] | 12.2 [3.4] | ≥10 | Nagueh et al. (2016) | 6 [19% (9, 35%)] | 0.005 |
| TR velocity [m/s] | NA | ≤2.8 | Nagueh et al. (2016) | 0 [0%] | ‐ |
| LA volume index [mL/m2] | 21.1 [5.3] | ≤34 | Nagueh et al. (2016) | 0 [0%] | ‐ |
| Presence of diastolic dysfunction by ASE criteria | 0 (0%) | >50% indicators positive | Nagueh et al. (2016) | 0 [0%] | ‐ |
| Vascular function | (n = 32) | ||||
| Peripheral SBP | 122 [21] | ≤140 | Jones, McCormack, et al. (2020) | 4 [13% (5, 28%)] | 0.074 |
| Peripheral DBP | 82 [14] | ≤90 | Jones, McCormack, et al. (2020) | 8 [25% (13, 42%)] | <0.001 |
| Peripheral HTN (either SBP or DBP HTN) | (n = 24) | ≥140/90 | Jones, McCormack, et al. (2020) | 9 [28% (14, 47%)] | <0.001 |
| Pulse wave velocity [m/s] | 7.5 ± 1.2 | b | Reference Values for Arterial Stiffness' Collaboration (2010) | 0 [0%] | ‐ |
| Muscle function | (n = 27) | ||||
| Hand‐grip strength [kPa] | 71.9 ± 18.3 | b | Massy‐Westropp et al. (2011) | 2 [7% (2, 23%)] | 0.394 |
| (n = 13) | |||||
| Knee extensor Pk. torque [Nm/kg] | 1.45 ± 0.67 |
Female: 1.26 (1.01–1.50) Male: 1.79 (1.34–2.23) |
Šarabon et al. (2021) | 2 [15% (4, 42%)] | 0.135 |
| Knee flexor Pk. torque [Nm/kg] | 0.71 ± 0.36 |
Female: 1.00 (0.78–1.21) Male: 1.03 (0.85–1.20) |
Šarabon et al. (2021) | 8 [62% (36, 82%)] | <0.001 |
| Autonomic function | (n = 28) | ||||
| SBP↓ after 1 min standing [mmHg] | 1 ± 11 | ||||
| SBP↓ after 3 min standing [mmHg] | −2 ± 11 | ≤20 | Schatz et al. (1996) | 1 [4% (1, 18%)] | 0.762 |
| HR↑ after 1 min standing [bpm] | 14 ± 9 | ||||
| HR↑ after 3 min standing [bpm] | 12 ± 8 | ≤30 | Freeman et al. (2011) | 2 [7% (2, 23%)] | 0.412 |
| Heart rate variability | (n = 26) | ||||
| RMSSD [ms] | 29 [29] | ≥19 | Nunan et al. (2010) | 5 [19% (9, 38%)] | 0.009 |
| LF [ms2] | 344 [734] | ≥193 | Nunan et al. (2010) | 10 [39% (22, 57%)] | <0.001 |
| LF normalized | 49 [35] | ≥30 | Nunan et al. (2010) | 4 [15% (6, 34%)] | 0.039 |
| HF [ms2] | 254 [828] | ≥83 | Nunan et al. (2010) | 5 [19% (9, 38%)] | 0.009 |
| LFHF | 0.95 [1.54] | ≤11.6 | Nunan et al. (2010) | 0 [0%] | ‐ |
| ↓RMSSD, ↓HF and ↓LF & ↑LF/HF ratio | ‐ | ‐ | ‐ | 0 [0%] | ‐ |
| Presence of at least one abnormal autonomic parameter | (n = 28) | ‐ | ‐ | 10 [36% (21, 54%)] | <0.001 |
| Hemoglobin status | (n = 25) | ||||
| Hemoglobin (Hb) [g/L] | 135 ± 11 |
Female: >120 g/L Male: >130 g/L |
World Health Organization (2011) | 5 [20% (9, 39%)] | 0.007 |
Note: Details are provided in full in references provided.
Abbreviations: ASE, American Society of Echocardiography; DBP, diastolic blood pressure; FEV1, forced expiratory volume in the 1st second; FEV1/FVC ratio, ratio of the forced expiratory volume in the 1st second to the forced vital capacity; FVC, forced vital capacity; GLS, global longitudinal strain; HF, high frequency; HR, heart rate; LA, left atria; LF, low frequency; LFHF, low frequency high frequency ratio; LVEF, left ventricular ejection fraction; OUES, oxygen uptake efficiency slope; Pk, Peak; RMSSD, root mean square of successive differences between normal beats; SBP, systolic blood pressure; TR, tricuspid regurgitation; V̇E/V̇CO2, ventilation/carbon dioxide production; V̇O2, oxygen uptake; V̇O2WR, oxygen uptake work rate.
Normative values were calculated using sex specific equations.
Normative values were stratified by sex and age decade.