Renal Protection with CO₂: A 90-Day Clinical Pathway for Approval, Risk Management, and KPI Implementation
A Kidney Preservation Clinical Pathway based on CO₂ angiography is a hospital care pathway designed to reduce exposure to iodinated contrast media during vascular procedures below the diaphragm, with the goal of decreasing the incidence of AKI/CA-AKI and related complications. This article is intended for Hospital Management, Clinical Governance teams, and Technology Assessment Committees that need to make transparent, evidence-based decisions regarding clinical criteria, risk management, Medical Device Regulation (MDR) requirements, staff training, and measurable performance indicators. Its value is practical: it provides a structured go/no-go framework together with a set of Key Performance Indicators (KPIs) for measuring outcomes over the first 90 days.
Why a "Kidney Preservation" Clinical Pathway—and Why Now?
Post-procedural acute kidney injury (AKI) and contrast-associated acute kidney injury (CA-AKI) have a significant impact on patient safety, hospital length of stay, readmissions, and healthcare costs. Across Europe, increasing pressure to improve clinical outcomes while optimizing reimbursement and healthcare sustainability makes it essential to standardize contrast-sparing strategies for patients with chronic kidney disease (CKD), diabetes, advanced age, dehydration, or multiple comorbidities. When appropriately indicated, CO₂ serves as an alternative contrast agent for peripheral vascular imaging and enables CO₂-first or Zero Contrast workflows in carefully selected patients.
A clinical pathway is more than a technology adoption decision—it is an exercise in clinical governance, informed consent, patient eligibility criteria, and clearly defined responsibilities. Without a formalized pathway, CO₂ angiography tends to remain an occasional, operator-dependent practice that is difficult to measure consistently. By implementing a structured clinical pathway, Hospital Management gains standardized practice, improved auditability, and a KPI dashboard aligned with the prevention of iatrogenic kidney injury.
Clinical Scope and Pathway Boundaries: Who, Where, and Which Procedures?
The most robust approach for a 90-day implementation is to begin with peripheral angiography and infra-diaphragmatic endovascular procedures performed in Interventional Radiology and Vascular Surgery, where the objective is to reduce or eliminate iodinated contrast exposure in patients at high renal risk. The pathway should clearly define its scope, including the clinical setting (angiography suite or hybrid operating room), the target procedures (diagnostic and therapeutic), patient inclusion criteria, and exclusion criteria or contraindications.
The pathway should also explicitly state that CO₂ is not a universal replacement for iodinated contrast media. Rather, it is a clinical option with specific indications and limitations. Safe implementation depends on appropriate patient selection, correct injection technique, catheter management, contamination prevention, and standardized injection protocols. At this stage, the primary governance objective is to transform what is currently an operator-dependent practice into a standardized, reproducible clinical process.
Clinical Governance and Risk Management (Safety, Contraindications, and Escalation Strategies)
Successful implementation requires a formally appointed multidisciplinary working group under the responsibility of Hospital Management or the Clinical Governance Office. Team members should include a designated clinical lead (Interventional Radiology or Vascular Surgery), a Risk Manager, representatives from Anesthesiology and Intensive Care, Nephrology for CKD patient management, Clinical Engineering and Pharmacy for medical devices and consumables, Procurement, and a Data Manager or ICT specialist responsible for traceability. This multidisciplinary group is responsible for defining institutional policies, training programs, audit processes, and escalation criteria.
Risk management should include a dedicated "safety-by-design" section covering patient selection, pre-procedural assessment of renal function (eGFR), hydration protocols where appropriate, management of nephrotoxic medications according to institutional policies, and adverse event response plans. For CO₂ angiography specifically, the pathway should clearly define contraindications and operational precautions in accordance with institutional clinical protocols, the manufacturer's Instructions for Use (IFU), and the clinical evidence adopted by the institution.
Another key component is the escalation strategy: what should happen when CO₂ imaging alone is insufficient or when the procedure requires completion using iodinated contrast media? The clinical pathway should establish predefined decision criteria, such as maximum acceptable iodinated contrast volume for high-risk patients, alternative imaging options, criteria for conversion to a hybrid imaging strategy, and documentation responsibilities. This level of clarity reduces both clinical risk and medico-legal exposure while ensuring consistent decision-making across the multidisciplinary team.
MDR Requirements and Procurement: What the Technology Assessment Committee Needs to Review
For approval by the Technology Assessment Committee, the submission dossier should demonstrate both regulatory compliance and appropriate clinical use. This includes CE marking in accordance with Regulation (EU) 2017/745 (MDR), availability of the Unique Device Identifier (UDI), Instructions for Use (IFU), approved indications and contraindications, maintenance requirements, and post-market surveillance procedures. The Committee should also verify that the device is integrated into the hospital's vigilance system, including incident reporting, consumable traceability, and field safety corrective action (FSCA) or recall management.
Procurement should evaluate not only the device's capital expenditure (CAPEX), but also operating costs (OPEX), single-use consumables, staff training, and change management support. In solutions such as the Angiodroid model (automatic CO₂ injector, dedicated consumables, and standardized protocols), the workflow itself is part of the technology. It reduces operator-dependent variability while facilitating standardization and clinical audit. For this reason, the Technology Assessment Committee should specifically assess how procedural standardization is achieved (standardized parameters, operating protocols, and pre-use safety checks) and how clinical adoption will be supported.
Digital Traceability: From Injection Parameters to Clinical Outcome KPIs
An effective Kidney Preservation Clinical Pathway must be measurable. Digital traceability should encompass three complementary data domains: patient information (baseline eGFR, serum creatinine, comorbidities, allergies), procedural information (procedure type, iodinated contrast volume, CO₂ use, procedure duration, intra-procedural complications), and outcome data (AKI/CA-AKI, dialysis, length of stay, and readmissions). Hospital Management should ensure that these data can be extracted efficiently, ideally through integration with the Radiology Information System (RIS), Picture Archiving and Communication System (PACS), the Electronic Health Record (EHR), and institutional business intelligence platforms.
To ensure meaningful before-and-after comparisons, the pathway should define a minimum dataset together with standardized documentation rules. In addition, digital recording of injection parameters and consumable usage supports both clinical audit and risk management by allowing complete reconstruction of protocol adherence in the event of an adverse event or internal review.
Multidisciplinary Training Program: Safely Reducing the Learning Curve
Introducing CO₂ angiography requires more than technical instruction. It demands multidisciplinary education focused on clinical decision-making, workflow standardization, and patient safety. The training program should involve interventional radiologists, vascular surgeons, nurses, radiographers, anesthesiology staff when appropriate, clinical engineers, and risk management personnel. The objective is to develop reproducible competence in patient selection, imaging technique, image interpretation, management of unexpected situations, and accurate clinical documentation.
A practical approach is a train-the-team model combining supervised clinical cases with short-cycle audits. Structured educational programs such as Angiodroid workshops and clinical mentorships help reduce early operator variability while accelerating the adoption of CO₂-first and Zero Contrast protocols in patients at increased renal risk. Hospital Management should require a formal education plan that includes learning objectives, attendance records, competency assessment, and clear authorization criteria before independent clinical use.
Go/No-Go Checklist for Approval and Implementation: Governance, Risk Management, and KPIs
- Governance and leadership: multidisciplinary working group formally established; clinical lead appointed; Risk Manager and Clinical Engineering involved; audit schedule defined.
- Clinical pathway scope: target infra-diaphragmatic procedures identified; participating departments and procedure rooms defined; inclusion and exclusion criteria established; escalation rules for iodinated contrast or hybrid strategies documented.
- Regulatory compliance (MDR): MDR CE marking verified; UDI and IFU available; maintenance and training plans established; vigilance and incident reporting integrated into institutional quality systems.
- Workflow and patient safety: written operating protocol (setup, contamination prevention, pre-use safety checks); documentation responsibilities defined; adverse event management process established; informed consent updated to explain the contrast-sparing/CO₂ strategy.
- Traceability and data management: minimum dataset defined; mandatory documentation fields in the EHR/RIS established; standardized recording of iodinated contrast volume and CO₂ use; data owner assigned; monthly data extraction schedule implemented.
- Training program: multidisciplinary education completed; practical simulation sessions performed; competency assessment criteria defined; mentoring during initial clinical cases; periodic refresher training scheduled.
- KPIs and baseline: operational definitions for AKI/CA-AKI, readmissions, and dialysis established; historical baseline (3–6 months) or comparable cohort available; 90-day targets defined; review process for results and scale-up decisions established.
- Economic assessment: estimated technology and consumable costs; expected impact on length of stay and readmissions; DRG and care pathway analysis; sustainability and scalability criteria documented.
Standard KPIs for Measuring Performance During the First 90 Days
KPIs should be limited in number, directly comparable, and closely linked to renal outcomes and healthcare costs. A standard Technology Assessment Committee dashboard should include the incidence of post-procedural AKI and/or CA-AKI according to the institution's adopted definition, total iodinated contrast volume per procedure and per patient, the percentage of CO₂-first and Zero Contrast cases, hospital length of stay (LOS), 30-day readmission rate, acute dialysis events, procedural complications, conversion to iodinated contrast, and selected economic indicators such as direct consumable costs, avoided hospital bed-days, DRG impact, and complication-related costs.
To produce robust 90-day comparisons, it is essential to define a homogeneous target cohort (for example, patients with eGFR below an institutionally defined threshold or documented CKD) together with a consistent procedural population. In the absence of randomized data, credibility depends on standardized definitions, comprehensive traceability, and rigorous clinical auditing rather than on the number of collected indicators. A concise report presented to the Technology Assessment Committee should complete the improvement cycle by summarizing clinical outcomes, protocol deviations, incident reports, proposed corrective actions, and recommendations regarding expansion of the clinical pathway.
How to Implement a Kidney Preservation Clinical Pathway with CO₂ in 90 Days
Step 1: Define the Clinical Scope, Patient Eligibility, and Baseline Data
Identify the target infra-diaphragmatic procedures and the patient cohort at increased renal risk. Establish inclusion and exclusion criteria together with escalation rules for iodinated contrast. Create a historical baseline (3–6 months) for AKI/CA-AKI, iodinated contrast volume, and hospital length of stay using standardized operational definitions.
Step 2: Prepare the Technology Assessment Dossier (MDR, Risk Management, and Procurement)
Assemble MDR documentation (CE marking, UDI, IFU), maintenance plans, and vigilance procedures. Formalize the institutional risk assessment, including patient selection, contraindications, adverse event management, and the economic evaluation covering CAPEX, OPEX, consumables, and expected effects on length of stay, readmissions, and DRG performance.
Step 3: Standardize Workflow and Digital Traceability
Develop a written operating protocol covering setup, pre-use safety checks, documentation requirements, and contamination prevention. Make documentation of iodinated contrast volume, CO₂ use, and renal outcomes mandatory within the EHR and RIS. Assign a data owner and establish a monthly schedule for data extraction and clinical audit.
Step 4: Deliver Multidisciplinary Training and Mentor the First Clinical Cases
Provide structured education for physicians, nurses, and radiographers, including escalation scenarios and competency requirements. Supervise the first clinical cases through mentorship and conduct early-cycle reviews to reduce technical variability while improving imaging quality and procedural safety.
Step 5: Measure KPIs and Decide on Program Expansion
At 30 and 90 days, produce a structured report including AKI/CA-AKI incidence, iodinated contrast volume, hospital length of stay, readmissions, dialysis events, conversion to iodinated contrast, and economic outcomes. Present clinical results, incident reports, and protocol adherence to the Technology Assessment Committee to determine whether the Kidney Preservation Clinical Pathway should be expanded or further optimized.
Frequently Asked Questions
What is a Kidney Preservation Clinical Pathway in angiography?
A Kidney Preservation Clinical Pathway is a structured hospital care pathway that integrates clinical criteria, standardized workflows, and outcome measurement to reduce iatrogenic kidney injury associated with iodinated contrast media. It includes patient selection, contrast-sparing or Zero Contrast protocols, risk management, and predefined Key Performance Indicators (KPIs). The expected outcome is a measurable reduction in AKI/CA-AKI incidence and related complications.
Does CO₂ always replace iodinated contrast media?
No. CO₂ is indicated for selected peripheral vascular procedures performed below the diaphragm and for carefully selected patients, particularly those at increased renal risk or with a history of severe iodinated contrast allergy. The clinical pathway should clearly define when to adopt a CO₂-first strategy, when a hybrid approach is appropriate, and when iodinated contrast remains clinically necessary.
Which MDR requirements should be reviewed by the Technology Assessment Committee?
At a minimum, the Committee should verify CE marking under Regulation (EU) 2017/745 (MDR), the availability of the Unique Device Identifier (UDI) and Instructions for Use (IFU), maintenance and training requirements, and integration into the hospital's vigilance system. Traceability of both the medical device and its consumables is also essential for clinical audits, post-market surveillance, and recall management. These elements ensure that adoption is both regulatorily compliant and clinically sustainable.
What are the minimum KPIs needed to evaluate impact during the first 90 days?
The minimum KPI set should include the incidence of AKI/CA-AKI within the target patient cohort, total iodinated contrast volume per procedure and per patient, and the percentage of contrast-sparing or Zero Contrast procedures. From a governance perspective, hospitals should also monitor length of stay (LOS), 30-day readmission rates, and—when clinically relevant—acute dialysis events. Using identical definitions before and after implementation is essential to ensure meaningful comparison.
How important is staff training for the safe implementation of CO₂ angiography?
Staff training is fundamental because procedural safety depends on appropriate patient selection, correct imaging technique, and consistent adherence to standardized protocols. A multidisciplinary education program combined with mentorship during the initial clinical cases reduces operator variability, improves image quality and traceability, and enhances patient safety. Hospital Management should require clearly defined learning objectives, competency assessment criteria, authorization requirements, and regular clinical audits to support continuous improvement.
