Hand crimping of stents

Hand crimping of stents

Hand crimping of stents can be resorted to when there is a need to reduce the cost or when the exact size of stent (diameter) is not available. Bare stents can usually be used in the range of 2.5 to 4 mm diameter in case of coronary stent. There can be slightly higher chance of stent getting dislodged from the balloon than in case of premounted stents, especially while negotiating tortuous vessels. The carrier balloon is prepared by connecting the inflation device and creating a vacuum. It may be useful to initially inflate and deflate it to check the proper functioning of the balloon and also check the match of the balloon length to that of the stent. After checking for leakage, balloon is put on negative pressure and re-wrapped. The distal end of the mounting tube is kept on the distal end of the carrier balloon and the stent is carefully slided on to the balloon using transverse force. A protection stylet is placed in the lumen of the carrier balloon. The stent is crimped starting from the proximal to distal end (distal to proximal of the balloon). Then the stent along with the balloon is rotated 90 degrees. The stent is crimped a second time. Firm crimping of the stent is continued with 45 degrees turns after each crimp, until optimum profile is obtained. The stent should not be rolled, twisted or kinked, nor should the balloon be turned while crimping. Stent and carrier balloon should be inspected and a slight pull on the stent may be applied to be sure that is securely and accurately loaded on the carrier balloon. The stylet is removed after the crimping is over. Never use sponge gauze to wipe the stent as the fibers could dislodge or pollute the stent. If there is any resistance while introducing the stent into the vessel, force should not be used as it can cause dislodgement of the stent. About 5% shortening can be expected while inflating above 3.5 mm diameter.

Hand crimping is an old technique in resource poor situations, seldom used or needed now.