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The Proxis System is indicated for use as a proximal embolic protection system to prevent distal release of and to aspirate embolic material (thrombus/debris) in saphenous vein coronary bypass graft(s) (3.0 mm – 5.0 mm) during percutaneous transluminal coronary angioplasty and/or stenting procedures.

The Proxis System is also indicated to control the flow of fluids and aid in the removal of fresh, soft emboli and thrombi in the coronary and peripheral vasculature.

The safety and effectiveness of this device as an embolic protection system has not been established in the cerebral, carotid or peripheral vasculature; native coronary arteries; or for treatment of patients with acute myocardial infarction.

The Proxis Embolic Protection System is used in conjunction with other percutaneous transluminal coronary angioplasty devices (PTCA). It is compatible with 8F guide catheters. The Proxis System protects the patient from distal embolization by preventing antegrade flow of emboli released during a PTCA and then removing it from the vessel. The Proxis System consists of an Evacuation Sheath Catheter, Accessory Pack (contains an inflation system, evacuation syringe and double y-adaptor) and an optional additional accessory called the Proxis Infusion Catheter (packaged separately).

The Evacuation Sheath Catheter is loaded into the hemostasis valve and tracked down to the distal portion of the guide catheter. The Evacuation Sheath lines the inner lumen of the distal end of the guide catheter. When the sealing balloons are inflated, the proximal balloon seals against the guide catheter wall and the distal balloon seals against the blood vessel wall and the antegrade flow of the fluid in the target vessel is stopped. The stagnation of flow is accomplished before any devices touch or cross the lesion(s). This minimizes the distal release of embolic material.

Interventional devices are passed through the evacuation sheath to the treatment site and the procedure is performed in stagnant fluid. After the procedure, fluid and particles from the procedure are evacuated using the Evacuation Syringe. The Proxis Infusion Catheter may be used to augment the retrograde flow during the evacuation by infusing saline distal to the treatment site while simultaneously applying vacuum to evacuate fluid and particles from the treatment site.

This document describes the Proxis System, an embolic protection device, and the study supporting its expanded indications. Here's an analysis of the acceptance criteria and the study details:

1. Table of Acceptance Criteria and Reported Device Performance:

The document describes the "Proximal Trial" which assessed the safety and effectiveness of the Proxis System for embolic protection. The primary acceptance criterion appears to be non-inferiority in the 30-day Major Adverse Cardiac Event (MACE) rate compared to existing distal protection devices.

Interpretation: The reported performance of the Proxis System (9.2% MACE in the test arm) and the control arm (10.0% MACE) demonstrates a difference of -0.8% (Proxis < Control). The upper confidence interval (CI) for this difference was 4% (for the ITT population) and 0.3% (for the as-treated population). Both of these are "well below" the absolute non-inferiority delta of 7.0% and the relative delta of 5.5%, indicating that the Proxis System was found to be non-inferior to the predicate devices.

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

• Sample Size: 600 randomized patients, with an additional 117 roll-in and 5 educational patients.
  • Included in Analysis: 594 randomized patients.
• Data Provenance: The study was conducted in 68 investigational sites across Canada, Europe, and the United States. It was a prospective clinical trial ("Proximal Trial").

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

The document does not specify the number of experts used to establish the ground truth for the MACE events, nor their specific qualifications. Typically, MACE events in clinical trials are adjudicated by an independent clinical events committee (CEC) composed of experts (e.g., cardiologists), but this detail is not provided in the summary.

4. Adjudication Method for the Test Set:

The document does not specify the adjudication method for MACE events (e.g., 2+1, 3+1, none). It mentions that "the 30 day MACE rate is 9.2% in the Test arm and 10.0% in the Control arm," implying that MACE events were tracked and presumably adjudicated, but the method is not detailed.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, and the effect size of how much human readers improve with AI vs. without AI assistance:

• No, an MRMC comparative effectiveness study was not done. This study is a clinical trial comparing two device-based interventions (Proxis vs. existing distal protection devices) in human patients, not an AI efficacy study involving human readers.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:

• No, a standalone algorithm performance study was not done. The Proxis System is a physical medical device, not an AI algorithm.

7. The Type of Ground Truth Used:

• The ground truth for the "Proximal Trial" was clinical outcomes data, specifically the occurrence of Major Adverse Cardiac Events (MACE) at 30 days. This involves documented clinical events such as death, myocardial infarction, and target vessel revascularization, diagnosed by medical professionals.

8. The Sample Size for the Training Set:

• Not applicable. The "Proximal Trial" is a clinical efficacy and safety trial designed to evaluate a physical medical device, not to train a machine learning algorithm. Therefore, there is no "training set" in the context of AI/ML.

9. How the Ground Truth for the Training Set was Established:

• Not applicable. As noted above, there is no training set for an AI/ML algorithm in this context. The study established the ground truth (MACE rates) from the observed clinical events in the randomized patient population.

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