YY/T 0694-2020Standard test method for measuring intrinsic elastic recoil of balloon-expandable stents (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces YY/T 0694-2008 "Standard Test Method for Elastic Retraction of Balloon Expansion Stents", and YY/T 0694-2008 In comparison, the main technical changes except for editorial changes are as follows.

---The two ends of the stent have been added as measurement locations (see 7.2);

---Added additional measurement locations determined according to the design properties of the bracket (see 7.2);

---Added the requirement to evaluate the expected maximum implant diameter of the stent (see 7.6).

Please note that certain contents of this document may involve patents. The issuing agency of this document is not responsible for identifying these patents.

Introduction

The purpose of this test method is to quantify the stent diameter return from the expanded diameter on the balloon to the relaxed diameter after the balloon is decompressed. Shrinkage.

This test method can be carried out at room temperature, unless a certain material has a special temperature requirement, the test temperature (if applicable) should be indicated in the report. Standard test method for elastic retraction of balloon expandable stents

1 Scope

This standard specifies the standard test method for the elastic retraction of balloon expandable stents.

This standard applies to stents made of materials whose diameter can be plastically deformed before and after release under the action of mechanical methods.

Note. This standard does not include all safety issues related to use. The user of this standard is responsible for determining its applicability by establishing an appropriate safety and health evaluation mechanism before use.

2 Terms and definitions

The following terms and definitions apply to this document.

3 Overview of test methods

The samples that represent the market can be stents that are pre-installed or assembled on the balloon during use. The delivery balloon is expanded to a nominal nominal pressure.

When the stent is still on the inflated balloon, measure the outer diameter of the stent at at least 3 axial positions, and each axial position needs to be approximately perpendicular to 2 Measure the outer diameter of the stent in the direction of. After the pressure of the balloon is relieved, the outer diameter is re-measured in the same or close position with the same method.

4 Importance and application

The minimum stent retraction is a necessary stent characteristic because it can reduce the minimum expansion that must be reached in order to obtain the final release diameter.

Large diameter. Compared with a stent with a small retraction rate, a stent with a large retraction rate needs to be expanded to a larger diameter to obtain the final release diameter. real In fact, excessive expansion of blood vessels due to implantation of stents may cause tissue damage and fail to achieve short-term and long-term effects. The retraction of the stent is The inherent characteristics of the support material and the influence of its geometric characteristics. Therefore, measuring the retraction of the stent is an indispensable part of evaluating the stent design.

See Appendix A, which contains an explanation of the importance of balloon-expandable stent elastic retraction test.

5 Instruments

5.1 Use non-compressive liquid (water is a representative liquid) to inflate the delivery balloon of the pre-installed stent. This method can achieve and maintain The pressure required to expand the diameter of the stent allows its diameter to be measured. At the same time, there must be an instrument to monitor the pressure.

5.2 The method of measuring the outer diameter of the stent without deformation, usually using an optical system calibrated and not in contact with the stent. Measurement The resolution of the measurement system should be 0.01mm or higher, and the accuracy of the system should be 2% or higher of the reading.