P157Myocardial blood flow response to vasodilator cardiac stress testing in patients referred for pre-kidney transplant risk assessment
Bibliographic record
Abstract
Background. A nuclear stress test is frequently ordered for risk assessment prior to kidney transplantation (KT). Myocardial blood flow (MBF) can be measured with 82Rb-PET which permits to estimate the rate of insufficient response to vasodilator stress, potentially leading to false negative results. Methods. We reviewed the PET/CT scans of 150 patients receiving hemodialysis (HD), 66 on peritoneal dialysis (PD) and 100 controls referred for dipyridamole stress PET/CT for pre-KT evaluation and suspected coronary artery disease, respectively. The tomographic PET images were qualitatively and quantitatively evaluated for the presence of ischemia, and a stress/rest MBF ratio >2 was considered an adequate response to dipyridamole. Patients were asked to abstain from eating and ingesting caffeinated drinks for 12 hours prior to testing. Results. The mean age of HD, PD patients and controls was 59, 58, 65 years. Among pre-KT and control subjects the MBF response was inadequate (Figure 1) in 36%-HD, 24%-PD and 24%-controls (p < 0.0001). Overall ischemia was identified in 10-HD patients (6.6%), 15-PD patients (23%) and 26-controls (26%) (p < 0.0001 HD vs other groups). The rate of ischemia among non-responders in the 3 groups was: 0%-HD, 40%-PD and 31%-controls (p < 0.001 HD vs other groups). The rate of non-responders among HD patients was the same for patients with an AV access (32%) or a central venous catheter (36%). Serum hemoglobin levels, and AV access blood flow rate were not predictive of lack of response to dipyridamole. Limitations. Retrospective design; we did not measure serum caffeine levels to ascertain that patients abstained from caffeine. Conclusions. More than one-third of HD patients failed to respond sufficiently to vasodilator stress compared with PD or control patients, potentially reducing the rate of detectable ischemia on myocardial perfusion imaging. Neither anemia nor vascular access type were predictive of vasodilator response. Future studies should evaluate the utility of alternate forms of cardiac stress testing with PET, such as dobutamine, in HD patients. If the no-response rate were to remain low, other forms of pre-KT risk assessment may be indicated. Abstract P157 Figure 1
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".