(136 days)
The iFR® Modality of the s5/s5i/CORE/CORE Mobile Precision Guided Therapy System is indicated in all blood vessels, including coronary and peripheral arteries, to measure intravascular blood pressure during diagnostic angiography and/or interventional procedures. The iFR® Modality is intended to be used in conjunction with currently marketed Volcano pressure wires.
The Volcano iFR® Modality is new software that calculates blood pressures in the coronary and peripheral vasculature through isolation of the cardiac wave cycle where intracoronary resistance is naturally constant and minimized and where intracoronary flow is maximized. This results in the ability to measure pressure without the administration of a hyperemic agent.
Pressure measurement is captured through the use of currently marketed pressure wires compatible with the currently marketed s5/s5i/CORE/CORE Mobile imaging and pressure measurement system.
Here's a breakdown of the acceptance criteria and study details for the Volcano iFR® Modality, based on the provided 510(k) summary:
Acceptance Criteria and Device Performance
The provided document does not explicitly state pre-defined acceptance criteria in terms of specific sensitivity, specificity, or accuracy thresholds. Instead, it presents the "Study Results" as the performance metrics achieved by the device. The conclusion states that "The results of the performance data demonstrate equivalence to the predicate device."
However, we can infer that the reported performance metrics (sensitivity, specificity, PPV, NPV, and diagnostic accuracy) act as the de facto "acceptance criteria" that the device met to demonstrate equivalence.
| Parameter | Acceptance Criteria (Inferred from Study Results) | Reported Device Performance |
|---|---|---|
| Sensitivity | Sufficiently high for clinical utility | 90.7% (225/248) [86.4%, 94.0%] |
| Specificity | Sufficiently high for clinical utility | 96.2% (425/442) [93.9%, 97.7%] |
| Positive Predictive Value | Sufficiently high for clinical utility | 93.0% (225/242) [89.0%, 95.9%] |
| Negative Predictive Value | Sufficiently high for clinical utility | 94.9% (425/448) [92.4%, 96.7%] |
| Diagnostic Accuracy | Sufficiently high for clinical utility | 94.2% (650/690) [92.2%, 95.8%] |
| Percentage of Lesions free from Hyperemic Agent | Sufficiently high for clinical utility | 69.1% (477/690) [65.5%, 72.6%] |
| Percentage of Patients free from Hyperemic Agent | Sufficiently high for clinical utility | 65.1% (389/598) [61.1%, 68.9%] |
Interpretation: The "acceptance criteria" are implied by the demonstration of a "statistically high correlation" with FFR and the favorable percentages of patients/lesions where hyperemic agents could be avoided.
Study Information
Here's the detailed breakdown of the ADVISE II study, which provided the clinical data for the iFR® Modality:
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Sample Size used for the test set and the data provenance:
- Sample Size: 690 lesions. 598 patients.
- Data Provenance: Prospective, observational, non-randomized, double-blind, global, multi-center registry. This indicates data from various countries/sites. Specific countries are not detailed in the summary.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The document states that the iFR values were calculated at the "core lab using the HARVEST software (investigators were blinded to the iFR results)." The ground truth (FFR) was obtained using "standard guidelines for the FFR procedure."
- Number of Experts: Not explicitly stated how many individuals or experts were involved in the "core lab" analysis or in performing the FFR procedures.
- Qualifications of Experts: Not explicitly stated, but performing FFR and interpreting its results typically involves interventional cardiologists or highly trained catheterization lab personnel. The "core lab" would likely have experienced personnel for data processing and analysis.
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Adjudication method for the test set:
- Not explicitly described as a formal adjudication process between multiple readers. The ground truth (FFR) was established from direct physiological measurement. The "Hybrid approach" used FFR to categorize a subset of iFR values, which is a predefined algorithm rather than an inter-expert adjudication. The "counts provided in the cells of the below 2x3 matrix were provided by the study core laboratory," suggesting a single source for applying the FFR criteria.
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If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- No, a multi-reader multi-case (MRMC) comparative effectiveness study focusing on human reader improvement with/without AI assistance was not explicitly mentioned or conducted as described. This study directly compared the iFR modality (software-calculated pressure measurement) against FFR (a standard physiological measurement) as a diagnostic tool. It wasn't about humans interpreting images with or without AI.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, the performance metrics (sensitivity, specificity, etc.) presented are for the iFR Hybrid method in comparison to FFR. The iFR calculation itself is an "algorithm only" process where the software calculates the iFR from pressure wire data. While physicians perform the initial data acquisition, the iFR value itself is generated by the device's software without human interpretation or adjustment of the core iFR calculation. The "Hybrid approach" then uses these iFR values to selectively determine if FFR is needed, which is also an algorithmic decision-making process.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc):
- The ground truth was established using Fractional Flow Reserve (FFR) measurements, which is a universally accepted physiological measurement of coronary stenosis severity performed using a pressure wire and a hyperemic agent (adenosine). FFR values ≤ 0.80 were considered indicative of ischemia, and FFR values > 0.80 were considered not ischemic. This is a physiological reference standard, often considered a gold standard in cardiology.
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The sample size for the training set:
- The document describes the ADVISE II study as providing clinical data to support the iFR modification. It does not explicitly mention a separate "training set" for the iFR algorithm within the context of this 510(k) summary. The iFR modality is described as "new software that calculates blood pressures." It's possible the core iFR algorithm was developed and trained prior to this study, or it might be based on physiological principles rather than machine learning training on a dataset. The ADVISE II study appears to be a validation study for the overall performance of the iFR modality, not a study used for "training" the algorithm.
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How the ground truth for the training set was established:
- As no training set is explicitly described in this submission for the iFR algorithm itself, the method for establishing its ground truth is not provided. The ADVISE II study focused on validating the iFR Modality against FFR.
§ 892.1560 Ultrasonic pulsed echo imaging system.
(a)
Identification. An ultrasonic pulsed echo imaging system is a device intended to project a pulsed sound beam into body tissue to determine the depth or location of the tissue interfaces and to measure the duration of an acoustic pulse from the transmitter to the tissue interface and back to the receiver. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II (special controls). A biopsy needle guide kit intended for use with an ultrasonic pulsed echo imaging system only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.