Mitral valve replacement with the Quattro stentless pericardial bioprosthesis: mid-term clinical and echocardiographic follow up.
Bibliographic record
Abstract
BACKGROUND AND AIM OF THE STUDY: Preservation of the subvalvar apparatus during mitral valve replacement (MVR) is associated with improved ventricular function and patient outcome. The Quattro valve is a chordally supported stentless mitral valve bioprosthesis that undergoes anticalcification treatment and is sutured to both annulus and papillary muscles heads, thus preserving annuloventricular continuity. The study aim was to assess the mid-term hemodynamic and functional results following MVR using the Quattro valve. METHODS: Between 1998 and 2005, a total of 76 patients received the Quattro valve at the authors' institution. A competing-risks methodology was used to determine the time-related prevalence of four mutually exclusive end-states: death; subsequent valve removal for dysfunction; subsequent valve removal for endocarditis; and survival without valve reoperation. Serial echocardiograms (n = 321) were collected, and regression models adjusted for repeated measures were used to model the longitudinal progression of the prosthesis mitral valve area (MVA), peak gradient (PG), mean gradient (MG), mitral regurgitation (MR) and ejection fraction (EF) over time. RESULTS: The median patient age was 33 years, and the most common underlying pathology rheumatic fever (46%). Of the patients, 35 (46%) had undergone a prior mitral surgery. A competing-risks analysis showed that, at 10 years after Quattro implantation, 11% of patients had died without subsequent replacement, 57% underwent valve replacement for dysfunction, 7% for endocarditis, and 26% remained alive without reoperation. Overall, 24 valves were explanted (five for endocarditis and 19 for valve malfunction). On multivariable analysis, risk factors for reoperation were prior mitral surgery (p = 0.03), especially prior MVR (p = 0.04). Serial echocardiographic data showed progressive increases in PG and MR, a decrease in MVA, and stable MG and EF. CONCLUSION: In a fairly young population, the longevity of the Quattro valve was limited by a high risk of endocarditis and reoperation requirement. In addition to valve degeneration, malfunction without structural change was a frequent cause of prosthesis replacement. This may be due to an unpredictable geometric ventricular adaptation to the prosthesis, with subsequent development of prosthesis insufficiency or subvalvar stenosis. Further evaluation is required to identify the best candidates to receive the Quattro bioprosthesis.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| 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".