CT-derived fractional flow reserve (FFRct) for functional coronary artery evaluation in the follow-up of patients after heart transplantation
Bibliographic record
Abstract
OBJECTIVES: Invasively measured fractional flow reserve (FFR) is associated with outcome in heart transplant (HTx) patients. Coronary computed tomography angiography (CCTA)-derived FFR (FFRct) provides additional functional information from anatomical CT images. We describe the first use of FFRct in HTx patients. METHODS: HTx patients underwent CCTA with FFRct to screen for cardiac allograft vasculopathy. FFRct was measured distal to each coronary stenosis > 30% and FFRct ≤ 0.8 indicated hemodynamically significant stenosis. FFRct was also measured at the most distal location of each vessel. Overall distal FFRct was calculated as the mean of the distal values in the left, right, and circumflex coronary artery in each patient. RESULTS: Seventy-three patients (age 56 (42-65) years, 63% males) at 11 (8-16) years after HTx were included. Eighteen (25%) patients had a focal hemodynamically significant stenosis (stenosis > 30% with FFRct ≤ 0.8). In the 55 patients without a hemodynamically significant focal FFRct stenosis (FFRct > 0.80), the distal left anterior descending artery FFRct was < 0.90 in 74% of the patients and 10 (18%) patients had ≥ 1 coronary artery with a distal FFRct ≤ 0.8, including 1 with a distal FFRct ≤ 0.8 in all coronaries. Overall distal FFRct in patients without focal stenosis was 0.88 (0.86-0.91), 0.87 (0.86-0.90), and 0.88 (0.86-0.91) (median with 25th-75th percentile) at 5-9, 10-14, or ≥ 15 years post-transplantation, respectively (p = 0.93). CONCLUSIONS: FFRct performed on CCTA scans of HTx patients demonstrated that 25% of patients had a focal coronary stenosis with FFRct ≤ 0.8. Even without a focal stenosis, FFRct values are often abnormal in HTx patients. KEY POINTS: • This is the first report describing the use of FFRct in in heart transplant patients. • FFRct identifies patients after heart transplantation with hemodynamically significant coronary stenosis. • Even without a focal stenosis, FFRct values are often abnormal in heart transplant patients.
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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 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".