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The Restep DVT System is a prescriptive device that helps stimulate blood flow in the deep veins of the legs and is intended for use in :- . Preventing Deep Vein Thrombosis due to the presence of risk factors for thrombus formation during orthopedic, trauma, neurology, urologic, critical care, general medicine obstetrics and general surgery.

The Restep DVT System consists of the Restep pump and compatible leg and foot compression garments. The system is a lightweight, portable, prescriptive pneumatic compression device that helps to stimulate blood flow in the deep veins of the legs through the use of pneumatically controlled single chamber pressure cuffs, actuated by an electronically controlled pump unit and solenoid valves.

The Restep DVT System is an intermittent pneumatic compression device intended to prevent Deep Vein Thrombosis (DVT). The 510(k) submission (K090308) indicates that no separate acceptance criteria or a dedicated study proving device performance against such criteria were performed for this device in the same way a diagnostic AI device might be evaluated. This device was deemed substantially equivalent to predicate devices based on technological characteristics and similar performance in pressure/cycle profile and blood flow augmentation.

Here's an analysis of the provided information based on your requested criteria:

1. Table of Acceptance Criteria and Reported Device Performance

• Sensitization: Material does not elicit a sensitization response (ISO10993-10).
• Irritation: Material is a non-irritant (ISO10993-10). | - Cytotoxicity testing (ISO10993-5) results indicate the material is non-cytotoxic.
• Sensitization testing (ISO10993-10) results indicate the material does not elicit a sensitization response.
• Primary skin Irritation testing (ISO10993-10) results indicate the material is a non-irritant.
  Overall: "results indicate that the material used will have negligible effects on the patient." |
  | Clinical Performance (Blood Flow Augmentation) | Produce a similar pressure/cycle profile and similar level of blood flow velocity augmentation in the femoral vein compared to predicate devices (specific quantitative acceptance criteria are not provided for "similar," but implied to be within an acceptable range for therapeutic equivalence). | Test results of the Restep DVT System and predicate devices have shown that the Restep DVT System produces a similar pressure and time profile whilst squeezing a patient's limb and this results in similar level of blood flow velocity augmentation, as measured in the femoral vein. |

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

The documentation does not explicitly state a specific "test set" sample size or its provenance (country of origin, retrospective/prospective) for a study intended to "prove the device meets acceptance criteria" in the way a diagnostic algorithm would.

Instead, the performance evaluation relies on bench testing (for pump and software) and biocompatibility testing (for garments) against established standards and in-house protocols. For clinical performance, it refers to:

• "test results of the predicate devices"
• "the Restep DVT System have been done for pressure/cycle profile, and blood flow augmentation on test subjects."

The number of "test subjects" for the blood flow augmentation comparison is not provided. The data provenance is also not specified.

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

Not applicable in the context of this device. The "ground truth" for electrical safety, EMC, software validation, pump output, and biocompatibility is based on adherence to published international standards and in-house testing protocols, not expert consensus on clinical cases.
For blood flow augmentation, the "ground truth" would be the measured femoral vein velocity, but this is a physiological measurement, not an expert-adjudicated ground truth.

4. Adjudication Method for the Test Set

Not applicable. This is not an AI diagnostic device that requires expert adjudication of cases. The performance is assessed through objective measurements against technical specifications and physiological responses in test subjects.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done

No, an MRMC comparative effectiveness study was not done. This type of study is typically used for diagnostic devices where human readers interpret images or data, and their performance is compared with and without AI assistance. The Restep DVT System is a therapeutic device (intermittent pneumatic compression).

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

Yes, in a sense, a standalone evaluation of the device's functional performance was central to its submission. The "algorithm" here would be the pump's control software and the pneumatic mechanism.

• Software verification and validation was performed.
• Performance testing of the output parameters and profiles of the pump was done to ensure it met its specifications (e.g., pressure, cycle times).
• The comparison for blood flow augmentation was described as "test results... on test subjects" measuring a physiological response directly, implying an "algorithm only" (device only) assessment of its effect.

7. The Type of Ground Truth Used

The "ground truth" for the various tests performed can be characterized as:

• Technical Specifications/Standards: For electrical safety, EMC, software validation, and pump output performance, the ground truth is defined by the requirements of the cited industry standards (e.g., UL, CSA, IEC, EN) and the device's design specifications (e.g., 40mmHg pressure, 12s inflate/48s deflate cycle).
• Biological/Chemical Assays: For biocompatibility (cytotoxicity, sensitization, irritation), the ground truth is derived from laboratory tests adhering to ISO10993 standards.
• Physiological Measurements: For blood flow velocity augmentation, the ground truth is the direct measurement of femoral vein velocity in test subjects.

8. The Sample Size for the Training Set

Not applicable. This device does not use machine learning or AI that would require a "training set." Its operation is based on fixed algorithms and pneumatic principles.

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

Not applicable as there is no training set for this device.

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