Prognostic Utility of Quantitative Perfusion PET in Patients With Prior CABG: Incremental Value of Myocardial Flow Reserve and Coronary Vascular Resistance
Bibliographic record
Abstract
BACKGROUND: The prognostic utility of quantitative positron emission tomography (PET) with myocardial blood flow (MBF) measurements in patients with prior coronary artery bypass grafting remains unestablished. We evaluated PET-derived myocardial flow reserve (MFR) and coronary vascular resistance (CVR) for risk stratification in patients who have undergone coronary artery pass grafting. METHODS: This retrospective study included consecutive patients undergoing Rubidium-82 PET myocardial perfusion imaging between May 2017 and November 2023. MFR and CVR were defined as the ratio of stress to rest myocardial blood flow and mean arterial pressure divided by stress myocardial blood flow, respectively. The primary end point was major adverse cardiovascular events (MACE), defined as a composite of cardiac mortality and nonfatal myocardial infarction. The secondary end point (expanded MACE) included MACE plus hospitalization for unstable angina or heart failure. Associations were assessed using multivariable Cox proportional hazards models after adjusting for clinical variables and PET parameters. RESULTS: A total of 556 patients (median age 72 years, 79% male) were included. Over a median follow-up of 676 (482–1077) days, 39 patients (7.0%) experienced MACE, and 74 (13.3%) experienced expanded MACE. Receiver operating characteristic analysis identified optimal cutoff values of 2.05 for MFR and 66.4 mm Hg·min·g/mL for CVR. Impaired MFR and CVR were each significantly associated with increased rates of MACE and expanded MACE (all P <0.001). Stratification by combined MFR and CVR status demonstrated significant differences in event rates across groups (all P <0.001). In multivariable analysis, MFR (≤2.05), CVR (≥66.4 mm Hg·min·g/mL), and their combination were all independently associated with MACE, with adjusted hazard ratio of 2.954 ([95% CI, 1.287–6.780]; P =0.011), 2.356 ([95% CI, 1.075–5.161]; P =0.032), and 5.437 ([95% CI, 2.700–10.950]: P <0.001), respectively. CONCLUSIONS: PET-derived MFR and CVR provide independent and incremental prognostic value in coronary artery bypass grafting patients, enhancing risk stratification beyond conventional perfusion and function parameters.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".