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HeartFlow FFRCT is a post-processing software for the clinical quantitative and qualitative analysis of previously acquired Computed Tomography DICOM data for clinically stable symptomatic patients with coronary artery disease. It provides FFRCT, a mathematically derived quantity, computed from simulated pressure, velocity and blood flow information obtained from a 3D computer model generated from static coronary CT images. FFRCT analysis intended to support the functional evaluation of coronary artery disease.

The results of this analysis are provided to support qualified clinicians to aid in the evaluation and assessment of coronary arteries. The results of HeartFlow FFRCT are intended to be used by qualified clinicians in conjunction with the patient's clinical history, symptoms, and other diagnostic tests, as well as the clinician's professional judgment.

FFRc v2.0 is post-processing image analysis software developed for the clinical quantitative and qualitative analysis of CT DICOM data. It is a tool for the analysis of CT DICOM-compliant cardiac images and data, to assess the anatomy and function of the coronary arteries.

The software displays the anatomy combined with function using graphics and text, including computed and derived quantities of blood flow, pressure and velocity, to aid the clinician in the assessment of coronary artery disease.

The HeartFlow FFRct v2.0 device is a post-processing software that uses previously acquired Computed Tomography DICOM data to provide FFRct (Fractional Flow Reserve derived from CT), a mathematically derived quantity from simulated pressure, velocity, and blood flow information. This analysis supports the functional evaluation of coronary artery disease in clinically stable symptomatic patients.

The device's performance was evaluated in two main clinical studies: HeartFlowNXT and FFRct v2.0 Clinical Validation. The FFRct v2.0 Clinical Validation re-processed the sequestered HeartFlowNXT data with the updated software version to demonstrate equivalence.

Here's a breakdown of the requested information based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for the HeartFlow FFRct v2.0 device were pre-specified target goals for per-vessel sensitivity and specificity, defined by the lower one-sided 95% Confidence Interval (LCL) being above the target rate.

2. Sample Size Used for the Test Set and Data Provenance

The test set for the FFRct v2.0 Clinical Validation study used the same data as the HeartFlowNXT study.

• Sample Size: 254 adult subjects, resulting in 484 vessels for direct comparison of invasive FFR and FFRct.
• Data Provenance: Prospective, multicenter study conducted at 11 sites in 8 countries across Canada, Europe, and Asia.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

• Number of Experts: Not explicitly stated, however, the text mentions that "All invasive FFR data was reviewed by an independent FFR/QCA core laboratory." This implies a group of qualified experts, but their specific number or individual qualifications are not detailed.
• Qualifications of Experts: The core laboratory specialized in FFR and Quantitative Coronary Angiography (QCA), indicating expertise in these areas.

4. Adjudication Method for the Test Set

• Adjudication Method: Not explicitly detailed. However, the mention of an "independent FFR/QCA core laboratory" reviewing all invasive FFR data suggests a standardized and likely adjudicated process for determining the ground truth, rather than relying on individual site interpretations.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

• MRMC Study: The document does not describe a Multi-Reader Multi-Case (MRMC) comparative effectiveness study involving human readers. Instead, it compares the performance of FFRct to site-read cCTA (which implicitly involves human interpretation) in a standalone manner against the FFR reference standard.
• Effect Size of Human Readers' Improvement with AI: Since no MRMC study with AI assistance vs. without AI assistance for human readers was reported, an effect size of human reader improvement with AI cannot be determined from this document. The comparison is between FFRct performance and initial cCTA interpretation.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

• Standalone Study: Yes, a standalone performance evaluation of the FFRct v2.0 algorithm was done. The study assessed the FFRct v2.0's ability to identify hemodynamically significant obstructions (FFR ≤ 0.80) directly against the invasive FFR reference standard, without human-in-the-loop interpretation of the FFRct results. The reported sensitivity and specificity values are for the algorithm's output.

7. The Type of Ground Truth Used

• Type of Ground Truth: The ground truth used was invasive fractional flow reserve (FFR) measurements, with a threshold of ≤ 0.80 indicating a hemodynamically significant obstruction. This is considered the standard of care in-vivo measurement in humans for determining the hemodynamic significance of coronary lesions.

8. The Sample Size for the Training Set

• Sample Size for Training Set: The document states that HeartFlow conducted three primary clinical studies for validation. The HeartFlowNXT study provided the clinical validation for the predicate device, FFRct v1.4. The FFRct v2.0 (the device in question) "was clinically validated using the sequestered HeartFlowNXT dataset to evidence equivalence." This implies that the HeartFlowNXT dataset was used as a validation set for FFRct v2.0, rather than a training set. The size of any explicit training set prior to this validation is not specified in the document.

9. How the Ground Truth for the Training Set Was Established

• Ground Truth for Training Set: As the document refers to the HeartFlowNXT dataset as a validation set for FFRct v2.0, it doesn't describe the establishment of ground truth for a distinct training set for v2.0.
  • For the HeartFlowNXT dataset itself (which served as the basis for predicate validation and v2.0 validation), the ground truth was "direct measurement of FFR (≤0.80) during cardiac catheterization". All invasive FFR data was reviewed by an independent FFR/QCA core laboratory. If any part of the HeartFlowNXT data was used for training or development of v2.0 (before final "sequestering" for validation), the ground truth would have been established the same way.

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