51Regional heterogeneity in the oxygenation reserve of women with syndrome-x
Bibliographic record
Abstract
OnBehalf: MUHC CMR Group INTRODUCTION: The pathophysiology of women presenting with acute coronary syndrome with no obstructive coronary artery disease, termed Syndrome-X, remains incompletely understood. Microvascular dysfunction of the coronaries and the myocardium have been suggested as a potential mechanism of disease. However, cardiovascular magnetic resonance imaging (CMR) studies investigating microvascular disease have presented conflicting results. Oxygenation-Sensitive CMR (OS-CMR), combined with a breathing maneuver, has emerged as a powerful tool to investigate the Myocardial Oxygenation Reserve (MORE) of the myocardium. PURPOSE: This study aims to assess microvascular dysfunction in women with Syndrome-X when compared to age-controlled healthy women utilizing OS-CMR. METHODS: Fourteen Syndrome-X patients (mean age 54.6+/-6.58 years) and eighteen age-controlled healthy participants (mean age 52.7+/-3.90 years) underwent a CMR scan on a 3T Siemens scanner. Functional parameters were obtained from 2- and 4-chamber long axis standard SSFP cine images using the biplanar method. OS-CMR parameters were obtained from Oxygenation Sensitive (OS) images obtained in the basal and mid-ventricular short-axis. A combined breathing maneuver of 60 seconds of paced hyperventilation followed by a maximal breath-hold was performed. Global MORE values were obtained as a percent change in signal intensity from the beginning of the breath hold to the 30 second timepoint. Three methods were used to assess regional homogeneity. Radial difference, circumferential difference, and combined difference OS values were obtained from analyzing the endocardial and epicardial layers of the myocardium independently. Radial difference is the sum of the absolute differences between the endo- and epicardium in each of the myocardial segments. Circumferential difference is the sum of the differences between myocardial segments within the endo- and epicardium. Combined difference is a sum of radial and circumferential differences. RESULTS: There was no significant difference in age, body mass index, body surface area, or cardiac output between the Syndrome-X and the healthy control participants. Syndrome-X patients had a significantly lower left ventricular ejection fraction than healthy control participants (76.45+/-6.88 vs. 71.5+/-5.89, p < 0.05). Global myocardial oxygenation reserve values were not significantly different in Syndrome-X (6.90+/-6.59) when compared to healthy controls (5.06+/-4.47). Syndrome-X patients had a significantly higher radial (p = 0.026), circumferential (p = 0.0037), and combined difference (p = 0.0026) when compared to healthy participants. CONCLUSIONS: While the global myocardial oxygenation response between women with Syndrome-X and healthy control women was not significant, significant heterogeneity within the myocardium is present. This may indicate that heterogenous microvascular dysfunction is present in this patient population.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".