(28 days)
The SPY System is an imaging system used in capturing and viewing fluorescent images for the visual assessment of blood flow as an adjunctive method for the evaluation of tissue perfusion, and related tissuetransfer circulation in tissue and free flaps used in plastic, micro- and reconstructive surgical procedures.
The Novadaq® Technologies SPY® Fluorescent Imaging System consists of 2 components: the SP2000 Imaging Device and the SPY Paq®. The SP2000 Imaging Device consists of an imaging head containing a charge coupled device (CCD) camera, a laser light source, motion sensor and distance sensor attached via an articulating arm to a mobile cart. The mobile cart contains a flat panel display, computer, electronics enclosure and printer. The SPY® System provides the surgeon with the capability to view record and replay fluorescent images of blood flow in vessels and bypass grafts of the heart. A laser light source is used to illuminate the area of interest. ICG is injected intravenously through the central or peripheral venous line, bypass pump, cardioplegia line and coronary graft and while it is passing through the vessels, the absorption of laser light causes excitation of the dye followed by emission of infrared energy. The result is a fluorescent image of blood flow and related tissue perfusion in the vessels. A CCD camera captures the image.
The provided document, K072222, is a 510(k) summary for the SPY® Fluorescent Imaging System (SP2000 model), specifically concerning a proposed change to allow the use of an alternative brand of Indocyanine Green (ICG) dye (ICG Pulsation®) in addition to the already approved IC-Green™.
The document does not describe a study that explicitly sets acceptance criteria for device performance and then proves the device meets those criteria with specific statistical metrics. Instead, it focuses on demonstrating substantial equivalence to previously cleared predicate devices and proving the safety and effectiveness of using the new brand of ICG with the existing system. The "acceptance criteria" can therefore be inferred from the rigorous testing and positive clinical outcomes reported in previously cleared indications and the current submission's focus on equivalence.
Here's an analysis based on the available information:
1. Table of Acceptance Criteria and Reported Device Performance
Since explicit acceptance criteria with numerical targets are not stated, the table below infers the performance goals based on the described safety and effectiveness outcomes. The "Reported Device Performance" reflects the evidence presented to demonstrate that these inferred criteria are met.
| Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|
| Safety: | |
| 1. No thermal damage to tissue: The system should not cause thermal damage to the area of interest, even after repeated imaging sequences. | 1. Exposure for the SPY® System is 35 mW/cm², "far below" the maximum permissible exposure of 327 mW/cm² established by ANSI for skin exposure. |
| 2. Pig studies demonstrated no increase in myocardial tissue temperature. | |
| 3. "Use of the SPY System does not cause any thermal damage to the area of interest, even after repeated imaging sequences." | |
| 2. No adverse physiological effects (cardiac, renal, hepatic): Use of the system should not induce changes in cardiac function (ECG, arterial pressure) or acute/long-term cellular, renal, or hepatic adverse effects. | 1. Pig studies demonstrated "no detrimental effects on heart function, coronary flow or peripheral pressure." |
| 2. Over 4000 CABG procedures in humans showed "no reports of adverse acute or long-term cellular, renal or hepatic effects." | |
| 3. "For the heart, there were no changes in electrocardiograms or arterial pressures during and/or following SPY use." | |
| 4. "There were no acute or long-term cellular effects of using the SPY System." and "There were no acute or long-term renal or hepatic effects of using the SPY System." | |
| 3. Compatibility with ICG: The system must function safely and effectively with both IC-Green™ and ICG-PULSION® brands of ICG. | 1. The document explicitly states the 510(k) "demonstrates the equivalence of IC-Green™ and ICG-PULSION ICG products when used with the SPY Intra-operative Imaging Device." |
| Effectiveness: | |
| 4. High-quality image acquisition: Ability to acquire high-quality, high-resolution fluorescent images of blood flow and tissue perfusion in vessels and grafts. | 1. Pig studies demonstrated the ability to "acquire high quality images in a simple and reproducible manner." |
| 2. "The SPY System was able to acquire high quality images of the entire vascular bed on each area of interest." | |
| 3. Clinical utility demonstrated "in producing high quality and resolution images of the entire vascular bed of the point of interest." | |
| 5. Clinical utility in identifying patency issues: Ability to non-invasively, quickly, and safely identify vascular issues (e.g., lack of patency in grafts) to aid surgeons in revision. | 1. Literature reports that the SPY System "was able to non-invasively, quickly and safely identify 17 conduits in 311 patients that required revision during the surgical procedures. In all cases the lack of patency was visualized clearly by the SPY System... allowing the surgeon to revise the graft thus decreasing subsequent myocardial infarctions and the morbidity and mortality associated with poor graft patency." |
| 6. Imaging capabilities through skin (for specific indications): Ability to image dermal and subdermal blood flow. (This is a specific indication for plastic, micro- and reconstructive surgery.) | 1. "The SPY System is capable of imaging through the skin to provide a visual assessment of dermal and subdermal blood flow." |
| Equivalence to Predicates: The updated device (with ICG-PULSION®) must be substantially equivalent to previously cleared SPY systems and predicate devices for its intended use, without raising new questions of safety or effectiveness. | 1. Animal studies, human experience, and in vitro testing from previous 510(k) clearances (K042961, K060867, K063345, K071037) demonstrated safety and effectiveness. 2. The current submission specifically "demonstrates the equivalence of IC-Green™ and ICG-PULSION ICG products when used with the SPY Intra-operative Imaging Device." 3. The FDA letter confirms the device is determined "substantially equivalent" for the stated indications, pending the drug approval for ICG-PULSION®. |
2. Sample Sizes and Data Provenance
- Test Set Sample Size:
- Human Data: Over 4000 CABG procedures.
- Animal Data: Six (6) pig studies.
- Data Provenance:
- Human Data: Retrospective and prospective (implied by "commercially available," "over 4000 CABG procedures," and "literature reports"). Originated in Europe, Japan, and Canada.
- Animal Data: Prospective (specifically conducted for original 510(k)).
3. Number of Experts and Qualifications for Ground Truth
The document does not explicitly state the number of experts used to establish ground truth for this specific 510(k) submission's equivalence testing of the ICG brands.
However, for the original studies and clinical utility, it refers to:
- "surgeons" using the system.
- "literature reports" from 12 peer-reviewed journal articles, implying assessment and validation by medical professionals (surgeons, clinicians, researchers).
The qualifications of these experts are not explicitly detailed but would implicitly be surgeons and other medical specialists involved in cardiovascular, plastic, micro- and reconstructive surgeries, and researchers in those fields who authored or reviewed the peer-reviewed articles.
4. Adjudication Method
The document does not describe a formal adjudication method (like 2+1 or 3+1 consensus) for the test set as would typically be done for a diagnostic AI device. The evaluation of patency and the decision for revision were clinical decisions made by the operating surgeons based on the real-time SPY system images. The "ground truth" here is the clinical outcome or intervention guided by the system's visualization.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study is mentioned comparing human readers with and without AI assistance. The SPY system is an imaging device, not an AI algorithm in the contemporary sense. It provides intra-operative visual assessment of blood flow to assist the surgeon, implying human-in-the-loop use. The document describes clinical utility and safety, not an improvement in human reader performance with AI versus without AI assistance.
6. Standalone (Algorithm Only) Performance
Not applicable. The SPY system is a medical imaging device used intra-operatively by surgeons to visualize blood flow. It is intrinsically a human-in-the-loop system and not a standalone algorithm.
7. Type of Ground Truth Used
The ground truth used is primarily clinical observation/outcomes and expert judgment (surgical decisions).
- For the original CABG use, the "lack of patency was visualized clearly by the SPY System... allowing the surgeon to revise the graft." The successful revision and subsequent decrease in myocardial infarctions and morbidity/mortality serve as ultimate clinical ground truth for the system's utility.
- For safety, lack of adverse events (cellular, renal, hepatic, cardiac function) observed during real-world use and animal studies serves as ground truth.
- For image quality, expert assessment by surgeons and researchers (implied by peer-reviewed publications) provides the ground truth.
- In pig studies, direct physiological measurements (heart function, coronary flow, peripheral pressure, myocardial tissue temperature) were used.
8. Sample Size for Training Set
The concept of a "training set" is not applicable as this is not an AI/machine learning device. The previous human experience and animal studies (from prior 510(k)s) could be considered analogous to a "development dataset" or "validation dataset" in that they established the device's fundamental capabilities.
9. How Ground Truth for Training Set Was Established
Not applicable as there is no training set in the AI sense. For the underlying science and validation of the device:
- Original 510(k) (K042961) and subsequent clearances:
- Animal studies: Physiological measurements, direct observation, and imaging outcomes in six pigs.
- Human experience: Intra-operative visual assessment by surgeons, clinical outcomes, and lack of reported adverse events over 4000 CABG procedures.
- In vitro testing: Conformance to electrical, electromagnetic, and laser safety standards (IEC, UL, CFR, ANSI).
The combination of these methods established the ground truth for the device's initial safety and effectiveness. The current submission leverages this existing ground truth to demonstrate equivalence for the new ICG brand.
§ 892.1600 Angiographic x-ray system.
(a)
Identification. An angiographic x-ray system is a device intended for radiologic visualization of the heart, blood vessels, or lymphatic system during or after injection of a contrast medium. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II.