Stent dislodgement force of drug-eluting coronary stents: a bench test

Coronary stent dislodgement can cause critical complications. The dislodgement force of coronary drug-eluting stents (DES) remains unknown. This study aimed to compare the dislodgement force and pattern of contemporary DES.

Five DES designs which commonly used in clinical practice were tested. The force at which the stent dislodges relative to the balloon was measured. For the shim test, peak displacement force, defined as the first peak force that occurs during stent displacement and peak dislodgement force, defined as the peak force required to completely dislodge the stent from the delivery system, were measured. Three examples of each of the stents were tested using the shim test.

The peak displacement force of Orsiro (3.1±0.8 N) was lower than that of Xience Sierra (5.8±0.5 N) [Firehawk 3.8±0.2 N, Resolute Onyx 4.5±1.5 N, Synergy 4.8±0.5 N (P=0.024)]. The peak dislodgement force was lowest in Orsiro (3.2±0.8 N) when compared to the other stents (Firehawk 6.6±0.6 N, Resolute Onyx 7.4±0.3 N, Synergy 11.8±0.4 N, Xience Sierra 11.1±1.6 N) (P<0.001); this remained significant in the multiple comparison analysis. During pullback of the stents, most stents buckled without removal. However, the whole Orsiro stent was completely removed from the delivery system.

The dislodgement force of DESs differed between stent designs. The Orsiro stent was lower than that of other DES; additionally, it easily removed the whole stent from the delivery system. During the coronary intervention, operators should consider stent design and be cautious when pulling DES back in lesions with calcifications or a previously implanted stent, which are at high risk for stent dislodgement.