ISO 25539-4-2021 pdf free download – Cardiovascular implants — Endovascular devices — Part 4: Application of ISO 17327-1 for coated endovascular devices.
4 Requirements for coating properties 4.1 General Subclauses 4.2, 4.3, and 4.4 address the requirements as related to ISO 17327-1 for vascular stents, endovascular prostheses and vena cava filters, respectively. The coating types identified in Table 1 are addressed in this document. A device can have multiple coatings, each of which can be identified as different or multiple coating sub-types. For example, a drug eluting stent with an absorbable matrix can fit into eluting and absorbable coating sub-types.
Evaluations identified in ISO 17327-1 will possibly not always be appropriate for all coated endovascular prostheses, vascular stents and vena cava filters. The device evaluation strategy described in ISO 25539- 1 and ISO 25539-2 guides the development of the rationale for the testing selected to evaluate the endovascular device based on the requirements of the device design and potential failure modes. Evaluation of generic coating properties listed in ISO 17327-1 and identified as necessary by the device evaluation strategy shall be completed. Evaluation of coating properties listed in ISO 17327-1 deemed as not necessary by the device evaluation strategy do not need to be completed. Due to the broad scope of ISO 17327-1, some terminology and associated requirements in that standard are appropriate for other types of nonactive surgical implants, but inconsistent with standard terminology and requirements for endovascular devices.
In these cases, more relevant terminology and requirements are presented in this document and correlated to the requirements in ISO 17327- 1. This includes the requirements for the consideration of adhesion strength and coating abrasion resistance. For the coatings and implants addressed in this document, these generic coating properties are evaluated by other tests. For example, adhesion strength is defined in ISO 17327-1:2018, as the “load per unit area required to separate the coating from the substrate.” For the coatings and implants addressed in this document, coating adhesion is considered part of the assessment of maintenance of coating integrity which is evaluated through other means such as simulated use, durability, and particulate generation. Thus, the specific characterization of the adhesion strength (i.e. load per unit area required to separate the coating from the substrate) is not required. Similarly, coating abrasion resistance is considered part of the assessment of maintenance of coating integrity. For chemistry-related surface modifications on the devices within the scope of ISO 25539-1, ISO 25539- 2, and ISO 25539-3, coating coverage integrity evaluation is addressed through corrosion testing, while corrosion resistance is not identified as a generic coating property in ISO 17327-1. Evaluation of porosity and pore size, surface wettability, and surface texture are generally not applicable to coatings on endovascular devices. The potential need to evaluate these properties can be identified through the device evaluation strategy.
4.2 Vascular stents In order to conform to the requirements of ISO 17327-1, the evaluation of drug coatings, non-drug coatings, and chemistry-related surface modifications of stents shall be conducted for the properties as outlined in Tables 3, 4, and 5, respectively. A description of column headings associated with Tables 3, 4, and 5 is provided in Table 2. The available test methods (non-mandatory) that can be of use in meeting the applicable requirements are provided in Tables 3, 4, and 5.ISO 25539-4 pdf download.