Outcome and Impact of Surgery in Paradoxical Low-Flow, Low-Gradient Severe Aortic Stenosis and Preserved Left Ventricular Ejection Fraction
Bibliographic record
Abstract
BACKGROUND: The clinical relevance and management of paradoxical low-flow, low-gradient aortic stenosis (LFLG-AS) with preserved left ventricular ejection fraction remain debated. The aim of this study is to determine the features and outcome of LFLG-AS assessed using cardiac catheterization. METHODS AND RESULTS: Between 2000 and 2010, 768 patients with preserved left ventricular ejection fraction (>50%) and severe AS (valve area ≤ 1 cm(2)) without other valvular disease underwent cardiac catheterization. Mean age was 74 ± 8 years, 42% were women, and 46% had associated coronary artery disease. The prevalence of LFLG (indexed left ventricular stroke volume <35 mL/m(2) and mean gradient <40 mm Hg), normal flow high gradient, normal flow low gradient, and low flow high gradient were 13%, 50%, 22%, and 15%, respectively. Compared with patients with normal flow high gradient, those with LFLG were significantly older, with significantly reduced systemic arterial compliance and vascular resistances and increased valvulo-arterial impedance (all P<0.05). Ten-year survival was reduced in LFLG-AS (32 ± 9%) compared with normal flow high gradient (66 ± 4%; P=0.0002). After adjustment for other risk factors, LFLG-AS was independently associated with reduced long-term survival (hazard ratio, 1.85; 95% confidence interval, 1.08-3.07; P=0.02). However, despite higher operative mortality, patients with LFLG-AS undergoing aortic valve replacement seemed to have better long-term survival than those managed conservatively (5-year survival rate: 63 ± 6% versus 38 ± 15%; P=0.007; hazard ratio, 0.23; 95% confidence interval, 0.09-0.59; P=0.002). CONCLUSIONS: This large cardiac catheterization-based study reports that the LFLG-AS entity is not rare and is associated with worse outcome whether treated medically or surgically. However, these patients may have better long-term survival if treated surgically. Further prospective studies are needed to confirm this finding.
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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 | 0.003 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".