Abstract 11676: Importance of Longitudinal Dyssynchrony in Low Flow Low Gradient Severe Aortic Stenosis Patients Undergoing Dobutamine Stress Echocardiography. A Multicenter Study (on behalf of the HAVEC group)
Bibliographic record
Abstract
Introduction: Patients with reduced left ventricular ejection fraction (LVEF), low-flow low-gradient aortic stenosis (LFLG AS) represent a challenging cohort with high morbidity and mortality. Low-dose dobutamine stress echocardiogram (DSE) is recommended for assessment of flow reserve (FR, defined as ≥ 20% increase in stroke volume) which is prognostically important. Hypothesis: Presence of longitudinal dyssynchrony (LD) is independently associated with no FR during DSE. Methods: 185 LFLG AS patients from 4 different institutions who underwent DSE between 1997 through 2013 were studied. Baseline LD, transverse dyssynchrony and strain analysis were performed using vendor-independent 2D CPA TomTec software using DICOM images from apical 2 and 4-chamber and feasible in 97% of patients (N=179). Multivariate logistic regression analysis of predictors of no FR was performed. Results: The mean age was 74 ± 9 yrs; LVEF 30 ± 10%; indexed AV area 0.44 ± 0.1 cm2/m2; mean AV gradient 24 ± 7 mmHg; mean QRS width 126 ± 32 msec and 28% of the cohort had a QRS width ≥ 130 msec. LD, pre-defined as maximum opposite wall delay ≥ 130 msec, was present in 83% (149/179) of study cohort, whereas FR on DSE was present in 54%. Coronary artery disease was more common in those without FR. Although baseline LVEF was not different according to FR status (p=0.23), greater LV stroke volume index (p=0.001) and longitudinal strain (p=0.004) were seen in those without FR. LD was more prevalent in patients without FR (90% vs 77%, p=0.02). On multivariate analysis (Figure 1), presence of LD (HR=4.58, p=0.01) was an independent predictor of no FR despite several adjustments. Conclusions: LD is very prevalent in patients with LFLG AS undergoing DSE. Quantification of LD provides important insights as LD is independently associated with no FR. Whether LD improves after valvular intervention and whether its correction confers a better prognosis to these patients remains to be studied.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".