The Role of Tissue Doppler Imaging in the Noninvasive Detection of Chronic Rejection after Heterotopic Cardiac Transplantation in Rats
Bibliographic record
Abstract
BACKGROUND: Chronic rejection is a risk factor for the development of cardiac allograft vasculopathy (CAV) in heart transplant recipients. A useful animal model to study the role of immunosuppressive strategies in the prevention of chronic rejection involves heterotopic abdominal cardiac transplantation in rats. The detection of rejection and concurrent CAV traditionally involves subjective serial palpation of the graft from a scale of 0 to 4, with 4 indicating vigorous beats. Recent advances in murine echocardiography, in particular Tissue Doppler imaging (TDI), may allow for objective in vivo monitoring of chronic rejection in this transplant model. OBJECTIVE: The objective of this study was to compare the diagnostic accuracy of murine echocardiography as compared to the abdominal palpation heart score for the noninvasive detection of chronic cardiac graft rejection. METHODS: In an animal model of heterotopic cardiac transplantation, 18 male Fischer and Lewis rats were used as donors and recipients, respectively. Abdominal palpation and murine transthoracic echocardiography were performed to assess in vivo function of the transplanted heart. Left ventricular (LV) structure and function and TDI indices, including endocardial velocity (Vendo) and strain rate (SR), were evaluated in the ectopic heart. Graft tissues were processed for histological examination and graded for chronic rejection. RESULTS: Abdominal palpation scores were obtained in all 18 rats; score 1 (n = 5); score 2 (n = 4); score 3 (n = 6); and score 4 (n = 3). The mean LV ejection fraction was significantly (P <0.01) lower in score 3 and 4 grafts as compared to score 1 grafts. There was no correlation between the abdominal palpation score and LV systolic function. There was a significant relationship between decreasing Vendo or SR values and increasing grades of rejection (r = 0.65, P <0.05 and r = 0.75, P < 0.05, respectively). CONCLUSION: TDI of the transplanted heart in rats is feasible, reproducible, and more sensitive than palpation for the detection of chronic rejection.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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".