Bibliographic record
Abstract
Question: Is duplex scanning superior to clinical vein graft surveillance with respect to amputation rates, quality of life, and cost following femoropopliteal or femorocrural vein bypass graft? Population: Between 1998 and 2001, patients from 29 centers in the UK and Europe who had a patent vein graft 30 days following femoropopliteal or femorocrural vein bypass surgery for critical ischemia, claudication or symptomatic popliteal aneurysms were recruited for the study. Methods and results: There were 592 patients included in this multicenter randomized controlled trial. Patients with patent vein grafts at 30 days were randomized to receive or not receive duplex surveillance in addition to clinical examinations and ankle-brachial indices at 6 weeks (time of recruitment), and 3, 6, 9, 12 and 18 months. Stenoses within grafts were defined as slow peak systolic velocity (<45 cm/s), or a ratio of peak systolic velocity in an area of stenosis to any other area within 2 cm of >2. The primary endpoints were time to amputation and time to vascular mortality (MI, CHF, arrhythmia or CVA). Secondary outcomes included graft patency (whether primary or secondary, assisted or unassisted), cost, and quality of life as measured by SF-36 and EuroQol. The primary endpoints were analyzed according to an intention-to-treat analysis using Cox-regression and Kaplan-Meier life tables, while secondary outcomes were analyzed by the Mann-Whitney test and a t-test. Approximately 11% of patients died during the study, while 12% withdrew (45% of which were due to amputations). There were significantly more diagnostic interventions in the clinical follow-up group (31% vs 22%, P = 0.01). Between the clinical follow-up and duplex groups, there was no difference in amputation rate (7% vs 7%) or vascular death rate (3% vs 4%). A greater proportion of patients in the clinical follow-up group had a stenosis in the graft identified at the end of the study (19% vs 12%, p = 0.04). There were no differences in Kaplan-Meier estimates of primary, primary assisted and secondary patency rates between the two groups at 18 months. No differences in quality of life as measured by SF-36 or EuroQol were detected between the two groups. The cost per patient was greater in the duplex group (US$ 1537 vs US$ 2406, p = 0.002). Conclusion: The authors conclude that surveillance with duplex scanning following femoropopliteal or femorocrural bypass was more costly, but did not result in lower amputation rates.
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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 | 0.009 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.004 | 0.004 |
| Insufficient payload (model declined to judge) | 0.275 | 0.129 |
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".