Drug-Eluting Stent Solutions: Deliverability in DES

Carey Kimmelstiel, MD
Carey Kimmelstiel, MD
Dr. Kimmelstiel is the Director of Interventional Cardiology at New England Medical Center in Boston, Massachusetts. He received his medical degree from M.D. State University, followed by residencies at Kings County Hospital- Downstate Medical Center, and fellowships at the University of Massachusetts Medical Center and Tufts-New England Medical Center. Dr. Kimmelstiel is a member of several professional societies, has been a principal investigator in numerous clinical trials and is a member of several journal editorial boards. Why is deliverability in drug-eluting stents (DES) so important in treating patients today? Regardless of the type of lesion you are treating, deliverability helps you implant the stent exactly where you want it. It is especially important in the treatment of difficult-to-reach lesions, such as those occurring in tortuous and/or calcified segments. Patients with these lesions are an increasingly important part of everyday practice. Given equal efficacy of devices, deliverability is certainly one of the most important features of a stent. How do you determine whether one device is better than another in terms of deliverability? Real-world experience is critical for determining relative deliverability and for learning the best way to deliver a stent. Deliverability data from randomized clinical trials typically are nonexistent, and therefore cannot aid in determining whether one device is more deliverable than another. More importantly, failure to deliver a stent is unusual in clinical trials because the patients for whom deliverability would be an issue are often excluded. What strategies do you employ to aid in deliverability when you are facing a challenging lesion? We are treating an increasing number of complex patient populations older patients, patients with diabetes, patients who have been previously treated. It is becoming more challenging to address these patients and their lesions percutaneously. In typical situations, I use the less invasive approach of a less stiff wire without enhanced support guide catheters. In tougher scenarios, I use a stepwise approach to incrementally increase both supportability of the guide and, more importantly, the stiffness of the wire. I often predilate to prepare the lesion for stent delivery and good apposition. Depending on plaque burden, I may assess the lesion by predilating with a semi-compliant balloon. In calcified lesions, I use rotational atherectomy. For very tortuous lesions and more distal lesions, I may initially opt to use a less stiff wire perhaps with a hydrophilic tip, and then exchange for a stiffer wire to straighten out the vessel to aid in device delivery. Predilatation is also very useful in these situations. The existing TAXUS® Stent on an Express2 platform is already a very deliverable stent and we should see even greater enhancements in deliverability as DES are improved. When would you use a bare-metal stent versus a drug-eluting stent? I use bare-metal stents in settings where DES are not appropriate, such as in smaller vessels and in vessels larger than 4.0 mm. There are also populations of patients where even though there is perhaps enhanced deliverability of the TAXUS Stent over competing devices, a DES cannot be delivered. In such a case, a bare metal stent can be useful. Are there certain mechanical features of a stent that aid in deliverability? More deliverable stents are being manufactured that employ different alloys, thinner struts and other features that will come into play in the operator’s decision. Cell design is certainly an important feature, not just for vessel coverage, but also in terms of conformability to the vessel and deliverability to more tortuous segments. Interestingly, subtle changes in stent design are driving product cycles. I think there will be great advancement in DES in the near future and going forward. Sponsored by Boston Scientific