Longitudinal Deformation of Drug-Eluting Stents: Evaluation by Multislice Computed Tomography

Background. Some modifications introduced in the design of the new generation of drug-eluting stent (DES) to improve their flexibility may entail a reduction in their longitudinal strength. This study sought to evaluate the longitudinal deformation of DESs by multislice computed tomography (MSCT). Methods. This study included DESs that could have been potentially deformed by mechanical actions such as: (1) catheter impingement; (2) postdilation; (3) kissing balloon; and (4) intravascular imaging after implantation. Patients on atrial fibrillation or with overlapping stents were excluded. All patients underwent stent length evaluation by MSCT 9-12 months after implantation. Results. Forty-five stents were included: 15 platinum chromium (PtCr-DES), 15 cobalt chromium (CoCr-DES), and 15 stainless-steel (SS-DES). The relative longitudinal deformation by stent type was 6.93 +/- 5.82% for PtCr-DES, 6.19 +/- 5.79% for CoCr-DES, and 4.03 +/- 4.07% for SS-DES (P=.31). Among the mechanical actions studied, only catheter impingement was related to longitudinal stent deformation (P<.01). After adjustment, only catheter impingement (P<.01) and nominal stent length (P=.049) were independently related to longitudinal deformation. There were no stent fractures. Conclusions. Longitudinal deformation of DESs is common in all the studied platforms when subject to longitudinal forces. Guiding catheter impingement is the only mechanical action significantly associated with DES shortening.