The Association of Matrix Metalloproteinases With Acute Kidney Injury Following CPB-Supported Cardiac Surgery
Bibliographic record
Abstract
Background: Cardiac surgery–associated acute kidney injury (AKI) is an adverse outcome that increases morbidity and mortality in patients undergoing cardiac surgical procedures. To date, the use of serum creatinine levels as an early indicator of AKI has limitations because of its slow rise and poor predictive accuracy for renal injury. This delay in diagnosis may lead to prolonged initiation in treatment and increased risk for adverse outcomes. Objective: This pilot study explores serum and urine matrix metalloproteinases (MMPs)-2 and MMP-9 and their association, and potentially earlier detection of AKI in patients following cardiopulmonary bypass (CPB)–supported cardiac surgery. We hypothesize that increased activity of serum and urine levels MMP-2 and/ or MMP-9 are associated with AKI. Furthermore, MMP-2 and/ or MMP-9 may provide earlier identification of AKI as compared with serum levels of creatinine. Methods: During the study period, there were 150 CPB-supported surgeries, 21 of which developed AKI according to the Kidney Disease Improving Global Outcomes criteria. We then selected a sample of 21 matched cases from those patients who went through the surgery without developing AKI. Primary outcomes were the measurement via gel zymography of the serum and urine activity of MMP-2 and MMP-9 drawn at the following intervals: pre-CPB; 10-minute post-CPB; and 4-hour post-CPB time points. Secondary variables were the measurement of serum creatinine, intensive care unit (ICU) fluid balance, and length of ICU stay. Results: At the 10-minute and 4-hour post-CPB time points, the serum MMP-2 activity of AKI patients were significantly higher as compared with non-AKI patients ( P < .001 and P = .004), respectively. Similarly, at the 10-minute and 4-hour post-CPB time points, the serum MMP-9 activity of AKI patients was significantly higher as compared with non-AKI patients ( P = .001 and P = .014), respectively. The activity of urine MMP-2 and MMP-9 of AKI patients was significantly higher as compared with non-AKI patients at all 3 time points ( P = .004, P < .001, P < .001), respectively. Conclusion: Although the pilot study may have limitations, it has demonstrated that the serum and urine levels of activity of MMP-2 and MMP-9 are associated with the clinical endpoint of AKI and appear to have earlier rising levels as compared with those of serum creatinine. Furthermore, in depth, exploration is underway with a larger sample size to attempt validation of the analytical performance and reproducibility of the assay for MMP-2 and MMP-9 to aid in earlier diagnosis of AKI following CPB-supported cardiac surgery.
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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 | 0.004 |
| 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 | 0.000 | 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".