AEGIS: An Operational Infrastructure for Post-Market Governance of Adaptive Medical AI Under US and EU Regulations
Organizations: Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 17177 Stockholm, Sweden · Department of Medical Radiation Physics, Stockholm University, Solna, Sweden · Department of Oncology-Pathology, Karolinska Institutet, Solna, Sweden · Department of Clinical Physiology, Karolinska University Hospital, 17176 Stockholm, Sweden · Department of Textile Technology, University of Bor˚as, Bor˚as 50190, Sweden · Department of Medical Technologies, Karolinska University Hospital, 141 57 Huddinge, Sweden · Department of Biomedical Engineering and Health System, KTH Royal Institute of Technology, 14157 Huddinge, Sweden
Abstract
Machine learning systems deployed in medical devices require governance frameworks that ensure safety while enabling continuous improvement. Regulatory bodies including the FDA and European Union have introduced mechanisms such as the Predetermined Change Control Plan (PCCP) and Post-Market Surveillance (PMS) to manage iterative model updates without repeated submissions. This paper presents AI/ML Evaluation and Governance Infrastructure for Safety (AEGIS), a governance framework applicable to any healthcare AI system. AEGIS comprises three modules, i.e., dataset assimilation and retraining, model monitoring, and conditional decision, that operationalize FDA PCCP and EU AI Act Article 43(4) provisions. We implement a four-category deployment decision taxonomy (APPROVE, CONDITIONAL APPROVAL, CLINICAL REVIEW, REJECT) with an independent PMS ALARM signal, enabling detection of the critical state in which no deployable model exists while the released model is simultaneously at risk. To illustrate how AEGIS can be instantiated across heterogeneous clinical contexts, we provide two examples: sepsis prediction from electronic health records and brain tumor segmentation from medical imaging. Both cases use identical governance architecture, differing only in configuration. Across 11 simulated iterations on the sepsis example, AEGIS yielded 8 APPROVE, 1 CONDITIONAL APPROVAL, 1 CLINICAL REVIEW, and 1 REJECT decision, exercising all four categories. ALARM signals were co-issued at iterations 8 and 10, including the critical state where no deployable model exists and the released model is simultaneously failing. AEGIS detected drift before observable performance degradation. These results demonstrate that AEGIS translates regulatory change-control concepts into executable governance procedures, supporting safe continuous learning for adaptive medical AI across diverse clinical applications.
Figures & tables
| Dimension | FDA (510(k)/ PCCP ) | EU MDR |
| Core Philosophy | SE | Continuous risk management |
| Foundational Question | “Is this device as safe and effective as something already proven?” | “Does the ongoing risk-benefit analysis remain acceptable?” |
| Evidence Paradigm | Comparative (new vs. predicate) | Cumulative (ongoing real-world evidence) |
| Clinical Data Focus | Premarket; 510(k) may rely on bench testing | Continuous clinical evaluation ( Post-Market Clinical Follow-up (PMCF) ) |
| Change Control Logic | Modifications within PCCP bounds maintain equivalence | Changes assessed against evolving risk profile |
| Methodological Backbone | Predicate device comparison | ISO 14971:2019 risk management |
| Parameter Categories | Description |
| Tolerance | Acceptable deviation from target value |
| Range | Minimum and maximum bounds for acceptable values |
| Reference | Reference values against which comparisons are made |
| Distribution Shift Metrics | KL divergence, JS distance, mean drift |
| Trustworthy AI (TAI) Metrics | Demographic parity, equalized odds metrics |
| Model Performance Metrics | Accuracy, sensitivity, specificity, AUC, F1-score |
| Decision | Question answered | Boolean Function f | Operator & Rationale |
| CHANGE-CONTROL DEPLOYMENT DECISIONS: new candidate model | |||
| REJECT | Is new model safe? | OR — any single safety failure blocks deployment | |
| CLINICAL REVIEW | Does new model need human validation? | OR — any metric in buffer zone, or any regression from (fixed performance reference comparison fails). | |
| CONDITIONAL APPROVAL | Does the new model need enhanced monitoring? | OR — minor drift or any TAI concern each independently warrant enhanced monitoring | |
| APPROVE | Does new model pass all checks? | AND — all checks must pass; any single failure routes to a lower category | |
| PMS ALARM SIGNAL: currently released model | |||
| Priority | Check | Condition | Decision |
| New Model Deployment Hierarchy (evaluate in priority order on and ) | |||
| P1 | deployment safety performance floor | REJECT | |
| P2 | performance buffer / regression from fixed performance reference | CLINICAL REVIEW | |
| P3 | minor drift / TAI | CONDITIONAL APPROVAL | |
| P4 | all pass | all checks passed | APPROVE |
| PMS ALARM Signal (evaluate in parallel using released model on ) | |||
| Parameter | AEGIS Definition | Sepsis Instantiation | Segmentation Instantiation |
| Data modality | Any supervised learning data | Tabular Electronic Health Record (EHR) time-series (202 features) | 3D multi-parametric Magnetic Resonance Imaging (MRI) |
| Model architecture | Agnostic (wrapper) | RF | nnU-Net ResENC-M |
| Primary metrics | Domain-configurable | Sens., Spec., ROC-AUC | Dice Similarity Coefficient (DSC) ( Tumor Core (TC) ) |
| MLcps weighting | User-defined via risk assessment | Sens.: 1.5, AUC: 1.3, Bal. Acc.: 1.1, Spec.: 1.0 (raw; normalized internally) | DSC : 1 |
| Drift detection | Pluggable method | Bonferroni-corrected Kolmogorov-Smirnov (KS) drift score | Performance comparison |
| Clinical thresholds | Risk-assessment derived (ISO 14971:2019) | Sens. 0.65 ∗ | DSC 0.676 ( TC ) ∗∗ |
| Decision | Definition | FDA PCCP Status | EU MDR / AI Act | Trigger |
| APPROVE | All metrics satisfied | Within PCCP scope | Art. 43(4) exemption | All pass |
| CONDITIONAL APPROVAL | Enhanced monitoring | Limited PCCP scope | Enhanced PMS | Minor drift or low trust scores |
| CLINICAL REVIEW | Human validation required | May exceed PCCP | Pre-modification review | Near threshold |
| ALARM | Released model at risk in field; issued as a PMS signal independently of the new model deployment decision | Activates PMS reporting; may require vigilance report depending on severity | EU MDR Art. 83 PMS obligation; potential Art. 87 serious incident notification | PMS safety performance floor breach; released model regression; major distributional shift |
| REJECT | Deployment blocked | New 510(k) required | New CA | Safety violation |
| AEGIS Parameter | Concrete Value | Clinical Justification | CDM Decision |
| Sens.: 0.723, Spec.: 0.933, AUC: 0.922 | performance of the first fully approved model on the Golden dataset | fixed performance reference | |
| Sens.: | derived from published systematic reviews of sepsis prediction performance [ 8 , 30 ] | REJECT | |
| Sens. Spec. | Performance thresholds (buffer zone) | CLINICAL REVIEW | |
| Major drift threshold | of 34 key features shifted ( KS test) | ALARM (A3) | |
| Minor drift range | Moderate distributional change detected | CONDITIONAL APPROVAL | |
| Sens.: | ALARM (A1) |
| Iter. | Sens. | Spec. | AUC | MLcps | Trigger | Routing Trace ∗ | Deploy. Decision | PMS Signal | ||
| 0 | 8,134 | 0.723 | 0.933 | 0.922 | 0.721 | 0.000 | All satisfied | P1 P2 P3 P4 | APPR. | — |
| 1 | 9,760 | 0.745 | 0.926 | 0.922 | 0.731 | 0.000 | All satisfied | P1 P2 P3 P4 | APPR. | — |
| 2 | 11,386 | 0.745 | 0.926 | 0.923 | 0.731 | 0.000 | All satisfied | P1 P2 P3 P4 | APPR. | — |
| 3 | 13,012 | 0.742 | 0.926 | 0.923 | 0.729 | 0.000 | All satisfied | P1 P2 P3 P4 | APPR. | — |
| 4 | 14,638 | 0.742 | 0.932 | 0.923 | 0.733 | 0.000 | All satisfied | P1 P2 P3 P4 | APPR. | — |
| 5 | 16,268 | 0.753 | 0.929 | 0.924 | 0.739 | 0.000 | All satisfied | P1 P2 P3 P4 | APPR. | — |
| Iter. | Trigger | Routing Trace* | Deploy. Decision | PMS Signal | |||
| 0 | 1150 | 0.726 0.313 | — | fixed performance reference | — | — | — |
| 1 | 200 | 0.646 0.337 | 0.694 0.325 | safety violation ( ) | REJ. | — | |
| 2 | 400 | 0.673 0.337 | 0.748 0.289 | safety violation ( ) | REJ. | — | |
| 3 | 600 | 0.690 0.326 | 0.745 0.308 | minor drift ( ; ) | APPR. | ALARM | |
| 4 | 800 | 0.700 0.321 | 0.758 0.284 | All satisfied ( ) | APPR. | — | |
| 5 | 1000 | 0.725 0.325 | 0.735 0.325 | minor drift ( ; ) | APPR. | ALARM |
| AEGIS Parameter | Concrete Value | Clinical Justification | CDM Decision |
| DSC : 0.726 | fixed performance reference. performance of the model trained on the full cohort on the Golden set ( TC region) | — | |
| 0.05 | Defines boundary. Clinically acceptable margin below fixed performance reference | — | |
| 0.676 | Minimum acceptable TC segmentation for treatment planning | — | |
| Performance falls below the minimum requirement for safe radiotherapy and surgical planning | REJECT | ||
| Non-regression condition: must match or exceed released performance reference | APPROVE | ||
| Regression condition: must be less than released performance reference | REJECT |
| Dimension | ABCDS (Duke) | FDA AILC | Babic et al. | AEGIS |
| Focus | Institutional governance | Conceptual lifecycle | Surveillance gaps | Operational implementation |
| Contribution | Committee structure | Phase-based model | Policy recommendations | Metrics-driven logic |
| Decision Mechanism | Committee review | Phase guidance | Quarterly updates | Threshold-based, five categories |
| Monitoring | Periodic human review | Conceptual | Recommended | Continuous with drift detection |
| Drift Detection | Not specified | Conceptual | Recommended | KS-test with threshold |
| Regulatory Mapping | Implicit | General | FDA MAUDE | Explicit PCCP / MDR / AI Act |
| Recommendation | AEGIS Implementation |
| Quarterly deployment updates | DARM iterative cycle; Table VIII shows 11 tracked iterations |
| Concept drift detection | MMM KS -test (threshold 0.90) triggers ALARM |
| Covariate shift monitoring | Golden dataset static; drifting dataset compared against reference |
| Algorithmic stability | fixed performance reference comparison (1% tolerance) |
| Subgroup tracking | MMM bias score across demographics |
Appendix figures & tables1 asset
Supplementary material from the paper’s appendix.
Appendix
| Symbol | Definition |
| Tolerance: acceptable deviation from target value | |
| Acceptable performance ranges for Golden/Drifting datasets | |
| fixed performance reference: performance of the first fully approved model on the Golden dataset. Set at first APPROVE; never updated. | |
| deployment/ PMS safety performance floor below which REJECT/ALARM is triggered | |
| candidate model performance on Golden/Drifting dataset at iteration | |
| fully approved released model performance on Golden/Drifting set |