Damage to polymer of undelivered sirolimus-eluting stents.

Background. Damage to the polymer coating on sirolimus-eluting stents (SES) may occur when it is delivered through complex lesions such as calcified lesions. The present study evaluated damage to the polymer of SES that could not be delivered into lesions. Methods. SES that could not be delivered into lesions were prospectively collected and examined using a scanning electron microscope. Results. There were 5 undelivered SES. In all cases, moderate or severe calcification with and without vessel tortuosity were reasons for unsuccessful delivery. Scanning electron microscopy demonstrated damage to the polymer of 4 out of the 5 undelivered SES. Conclusion. Damage to the polymer coating of SES may occur when delivered through a calcified coronary artery.