Active Medical Device Product Use Period Verification Requirements

Active medical devices have the functions of disease diagnosis, prevention, monitoring and treatment, etc. In order to maintain the above functions in clinical use, the registrant is required to determine the use period of the product. Within this period, not only to ensure the safety use, but also ensure the effective use of the product. Therefore, when registering active products, the basis for determining the expected use period of the product and the verification report must be submitted. In previous registrations, we found that companies have many questions about the validation of the use period, this paper will explain the validation of the use period (expiration date) of active medical devices from the definition, evaluation methods, evaluation path, and influencing factors.

Definition

Use period of active medical device: The use period during which the safe and effective use of a product can be assured by the applicant for medical device registration through risk management, and during which the product can maintain its scope of application.

Expiration date: The end of the use period, after which the safety and effectiveness of the medical device cannot be guaranteed. The use period of an active medical device is from the date the device is made into an end product to the expiration date, including both the time period before the device is put into use and the time period after the device is put into use.

Expected duration of use of active medical devices: The expected period during which the medical device applicant ensures the safe and effective use of the product through risk management before its launch, during which the product can maintain its scope of application.

Evaluation Methods

There are two ways of determining the use period of a product:

• Setting a predetermined use periodbased on evaluation or experience, and then verifying the reasonableness of the predetermined value by one or more methods.
• The product’s use periodis determined by one or more methods without setting a predetermined duration of use.

Evaluation Paths

There are two evaluation paths:

• Direct verification of the product. We list the state of use of the product, completely analyze the clinical use, and directly conduct real-time aging tests or accelerated aging tests, etc. of the product. The frequency and intensity of clinical use and the requirements of the use environment should be considerated during the test.
• Evaluate the product (system) by decomposing it into different subsystems/components. First, the decomposition relationship should be analyzed, and based on this, the service life of the product should be determined by different ways of decomposition (e.g., by dividing the product into critical and non-critical parts and/or featured and non-featured parts and/or replaceable and non-replaceable parts and/or moving and non-moving parts and/or electronic and mechanical parts, etc.).

Influencing factors

To determine the use period of active medical devices, the following aspects need to be considered: critical components such as high integrity components, frequency and intensity of use, transportation, storage and use of the environment, cleaning and disinfection, packaging and sterilization, maintenance and repair of components and commercial factors. In addition to analyzing the above factors, the registrant should also evaluate the product’s useful life through the dynamics of the product’s risk analysis throughout the life cycle process.

Evaluation methods

When evaluating the use period of a product, first of all, an evaluation program (including a sampling plan) should be formulated, including the purpose of collecting products/components, the number of and reasons for selection, the selection standards, and sampling batch; in conjunction with the influencing factors mentioned above, specify the specific assessment methodology to be used in evaluating the duration of use; secondly, the results should be tested according to the evaluation program or by other means, leading to an analytical report.

• Prospective studies of products/critical components using accelerated aging tests and/or validation with real-time aging correlations
• Aggregate studies in conjunction with experience with this or similar products, which may involve testing of samples, installation and use, repair rates or repair records, complaint histories, or research in the open literature.
• Analytical methods, simulation test methods/theory and simulation calculation methods for evaluating product/critical component reliability.

The above methods can be used individually or in combination. Other rational and scientific methods can also be used.

01 Verification of different components

The service life of critical electronic components is evaluated by analyzing methods such as reliability prediction or reliability simulation. Evaluate the service life of mechanical components by using life acceleration tests or direct clinical scenario cumulative tests.

02 Principles of analogies

Similar products/components should ensure that the hardware structure and materials are basically the same, the electrical performance index (voltage, power, current) is close, the main process flow is similar, work environment and clinical should refer to products/components with close intensity of use.

03 Empirical data

The useful life of a registered product can be inferred from data on the use of domestic and foreign marketed products of the same type. The following characteristics should be taken into consideration when using available empirical data to evaluate the use period:

• Authenticity: market data should be authentic and reliable;
• Adequacy: market data should be large enough and cover a long enough period of time for statistical analysis;
• Unbiased: market data should be selected without bias or selectivity;
• Traceability: market data should be traceable and their traceability chain should be reliable.

Information on the distribution of data with the above characteristics should be provided, giving confidence intervals.

Types of accelerated tests

The first article of the previous section on the specific evaluation and analysis methods for product life expectancy mentions that “prospective studies of products/critical components using accelerated aging tests and/or validation with real-time aging correlations”, so how should accelerated aging tests be conducted? What are the types of this test method? According to GB/T 34986-2017 “Accelerated Test Methods for Products”, based on the cumulative damage model, relevant information obtained from experiments, and assumptions about the product’s usage status, accelerated testing methods are divided into three types:

Category A (qualitative accelerated test): used to identify failure modes and/or failure events.

Category B (quantitative accelerated test): used to predict the distribution of failures during normal use.

Category C (quantitative time and event compression tests): used to predict the distribution of failures during normal use.

The test time can be shortened by accelerated tests of categories B and C. Category B accelerated tests need to be based on a specific failure mechanism and are usually applied to accelerate the life of a product. If a category C acceleration test is selected, it is necessary to investigate how it will be used prior to the test and to make assumptions about the specific conditions under which it will be used, which can be applied to failure rate acceleration.