Transapical Transcatheter Aortic Valve Implantation in Humans
Bibliographic record
Abstract
BACKGROUND: Aortic valve replacement with cardiopulmonary bypass is currently the treatment of choice for symptomatic aortic stenosis but carries a significant risk of morbidity and mortality, particularly in patients with comorbidities. Recently, percutaneous transfemoral aortic valve implantation has been proposed as a viable alternative in selected patients. We describe our experience with a new, minimally invasive, catheter-based approach to aortic valve implantation via left ventricular apical puncture without cardiopulmonary bypass or sternotomy. METHODS AND RESULTS: A left anterolateral intercostal incision is used to expose the left ventricular apex. Direct needle puncture of the apex allows introduction of a hemostatic sheath into the left ventricle. The valve prosthesis, constructed from a stainless steel stent with an attached trileaflet equine pericardial valve, is crimped onto a valvuloplasty balloon. The prosthetic valve and balloon catheter are passed over a wire into the left ventricle. Positioning within the aortic annulus is confirmed by fluoroscopy, aortography, and echocardiography. Rapid ventricular pacing is used to reduce cardiac output while the balloon is inflated, deploying the prosthesis within the annulus. Transapical aortic valve implantation was successfully performed in 7 patients in whom surgical risk was deemed excessive because of comorbidities. Echocardiographic median aortic valve area increased from 0.7 +/- 0.1 cm2 (interquartile range) to 1.8 +/- 0.8 cm2 (interquartile range). There were no intraprocedural deaths. At a follow up of 87 +/- 56 days, 6 of 7 patients remain alive and well. CONCLUSIONS: This initial experience suggests that transapical aortic valve implantation without cardiopulmonary bypass is feasible in selected patients with aortic stenosis.
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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 | 0.002 | 0.002 |
| 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 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
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".