Abnormal coronary vascular response in patients with long COVID syndrome – a case‐control study using oxygenation‐sensitive cardiovascular magnetic resonance
Bibliographic record
Abstract
BACKGROUND: Following the worldwide coronavirus disease 2019 (COVID-19) pandemic, many patients reported ongoing severe cardiovascular symptoms after the acute phase. This multisystemic condition has been named long COVID syndrome. While cardiovascular magnetic resonance (CMR) imaging is the gold standard to diagnose acute myocardial damage, no specific changes have been shown in long COVID patients. However, endothelial dysfunction has been hypothesized to contribute to its pathogenesis. Oxygenation-sensitive CMR during breathing exercise is a simple, non-invasive, and accurate test to objectify vascular function, which has not been applied to long COVID patients yet. METHODS: After receiving approval from the local ethics committee, this prospective observational case-control study enrolled (i) patients reporting symptoms for ≥6 weeks following an acute COVID-19 infection or vaccination, and (ii) healthy volunteers with neither symptoms nor history of cardiovascular disease. Participants completed a questionnaire, point-of-care testing of cardiac biomarkers, a standard non-contrast CMR, and an oxygenation-sensitive CMR. Heart rate response and breathing-induced myocardial oxygenation reserve (B-MORE) were assessed during metronome-paced hyperventilation and apnea. RESULTS: Thirty-one patients (17 female; age 39.4 [30.3; 51.6] years) and 27 controls (12 female; age 33.3 [27.3; 46.8] years) were included with comparable demographics and cardiovascular risk factors between groups. Laboratory testing and standard CMR did not reveal any pathologies in either of the groups. Indexed left ventricular stroke volume was significantly lower in patients (44.5 mL [41.2; 46.6] vs 55.9 mL [49.2; 59.2]; p < 0.001), while ejection fraction and longitudinal strain of both ventricles were comparable (p > 0.05 for all). Vasoactive breathing exercises induced a significant increase in heart rate (+35/min [21; 45]) and B-MORE (9.8% [4.3; 17.2]) in controls. In patients, however, heart rate increase was blunted (+15/min [7; 26]; p < 0.001) and B-MORE was significantly lower (7.3% [3.4; 10.4], p = 0.044). CONCLUSION: This pilot study is the first to show a blunted hemodynamic and myocardial oxygenation response to vasoactive breathing maneuvers during oxygenation-sensitive CMR in long COVID patients. This simple, non-invasive test may be the first to objectify complaints of affected patients and indicates evidence for the crucial role of the endothelium in the pathophysiology of long COVID.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".