Abstract 255: A Normokalemic Nondepolarizing Cardioplegia Minimizes Myocardial Injury and Improves Cardiac Function in a Large Animal Model of Donation After Cardiocirculatory Death
Bibliographic record
Abstract
Background: Procurement of donor hearts is typically preceded by delivery of a cold hyperkalemic cardioplegia (CP) that achieves arrest by depolarization of the membrane potential. This method has no intrinsic cardioprotective properties and may exacerbate ischemia-reperfusion (IR) injury. A tepid adenosine-lidocaine (AL) non-depolarizing CP has been shown to limit IR injury and improve myocardial functional recovery in a small animal model of orthotopic heart transplantation. We sought to determine the impact of AL CP on myocardial injury and function, in a porcine model of donation after cardio-circulatory death (DCD). Methods: Female Yorkshire pigs (60 kg) were subjected to a hypoxic cardiac arrest. Following a 15-minute standoff period donor hearts were procured, resuscitated ex-vivo, and transplanted into a recipient animal. Hearts in group 1 (N=7) were protected with a cold blood-Plegisol CP, perfused with a blood-crystalloid solution during ex-vivo assessment, and arrested with a cold blood-Plegisol CP prior to transplantation. Hearts in group 2 (N=5) were protected with a tepid AL-STEEN CP and perfused with a blood-STEEN solution in a continuous fashion during ex-vivo assessment and transplantation. Results: Animals in group 2 had a significantly longer ex-vivo perfusion time compared to those in group 1 (174±29 vs. 135±45 min, p<0.05), yet they demonstrated significantly less weight gain (14±4 vs. 25±8 grams/hour, p<0.05). Further, animals in group 2 exhibited less troponin I release during ex-vivo perfusion and had significantly better diastolic function following wean from cardiopulmonary bypass (left ventricular end-diastolic pressure volume relationship 0.115±0.052 vs. 0.508±0.223, p<0.05). However, there was no significant difference in level of calpain activity between groups (171.3±68.6 vs. 140.12±50.6, p=0.36). Conclusion: A tepid non-depolarizing AL CP results in less myocardial edema during ex-vivo perfusion, minimizes myocardial injury, and improves diastolic function following transplantation of DCD hearts, but fails to eliminate the activation of calcium-dependent proteases. Further studies should investigate if a calpain inhibitor delivered at reperfusion could further minimize IR injury in DCD hearts.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".