Effectiveness of the proximal optimization technique for longitudinal stent elongation caused by post-balloon dilatation.

Abstract

To evaluate the effectiveness of the proximal optimization technique (POT) to prevent longitudinal stent elongation. The mechanism of stent elongation, which occurs after post-balloon dilation, is still unclear. A total of 103 lesions treated with optical coherence tomography guided coronary intervention between May 2013 and November 2017 were retrospectively analyzed. Lesions were divided according to the circumferential degree of malapposition at the stent edge immediately after deployment into well-apposed group (<180°) and malapposed group (≥180°). Post-dilation was performed from distal to proximal within the stent until August 2016 (non-POT cohort), and POT was applied thereafter (POT cohort). In the POT cohort, post-dilation was done at the proximal portion of the stent with sufficiently large balloon to minimize malapposition followed by distal dilatations. Stent elongation length was defined as the change in stent length from stent deployment to after post-dilatation. In the non-POT cohort, 72 lesions, including 54 lesions in the well-apposed group and 18 in the malapposed group were analyzed. Stent elongation length was significantly longer in the malapposed group than in the well-apposed group (1.51 ± 1.34 mm vs 0.13 ± 0.84 mm, P < 0.01). In the POT cohort, 31 lesions including 21 in the well-apposed group and 10 in the malapposed group were analyzed. Stent elongation length was not significantly different between the groups (-0.09 ± 0.91 mm vs 0.30 ± 0.99 mm, P = 0.29). Malapposition of the stent edge is responsible for longitudinal stent elongation caused by post-dilatation. POT appeared to effectively prevent longitudinal stent elongation.