We implanted either large or medium Palmaz stents, or a Palmaz Corinthian stent, in various stenotic vessels, such as the pulmonary arteries, pulmonary veins, aorta, or superior caval vein. Using angiograms, we measured the diameter of the stenotic vessel before or after the implantation, the minimal diameter of the lumen, the minimal diameter of the largest fully expanded balloon used to expand the stent, and the diameter immediately after withdrawal of the balloon.
The minimal diameter of the fully expanded balloon, and the minimal diameter of the lumen subsequent to expansion, were 8.2 ± 2.4, and 7.7 ± 2.3 mm, giving an absolute recoil of 0.5 ± 0.4 mm, and a proportional recoil of 7 ± 4%. There was no significant difference in either the absolute or proportional recoil for any of the stents, or for any of the different stenotic vessels. The proportional recoil correlated linearly with the minimal diameter of the lumen prior to the procedure, and with the ratio of the stenosis to the balloon, while the diameter of the stenotic vessels, the minimal diameter of the largest fully expanded balloon, the proportional stenosis prior to the procedure, and the ratio of the balloon to the diameter of the stenotic vessel, had no significant correlation with proportional recoil. The proportional recoil exceeded more than one-tenth when the minimal diameter of the lumen prior to the dilation was less than 3 mm, or the ratio of the balloon to the stenosis was greater than 3.0.
An absolute recoil of around 1 mm is common when a large or medium Palmaz, or a Palmaz Corinthian stent, is implanted in great vessels. Balloons with a diameter of approximately one-tenth greater than that of the adjacent vessel may be needed if the minimal diameter of the lumen is small prior to the procedure.