Top 10 Tricks for Choosing the Right Stent
In addition to size and polymer choice, there are many additional factors that go into choosing the perfect stent that fellows need to take into account.
David Kandzari, MD (Piedmont Heart Institute, Atlanta, GA), is an interventional cardiologist and investigator who specializes in complex peripheral and coronary revascularization and is a member of the US Food and Drug Administration’s Circulatory System Devices Panel. Previously, he was the director of interventional cardiology research at the Scripps Clinic (La Jolla, CA) and served as Chief Medical Officer for the Cordis Corporation. He talked with TCTMD’s Fellows Forum to discuss his Top 10 Tricks for proper stent selection.
1. Evaluate efficacy
In the early 2000s, US practitioners were “consumed” by certain angiographic performance metrics associated with DES like restenosis, late lumen loss, and how potent antiproliferative drugs were in reducing neointimal hyperplasia within stented segments, Kandzari remembers. Then, efficacy was “of paramount importance to us as interventional cardiologists,” he said, and several subsequent studies compared different drug-eluting stents based on their efficacy and less so on “more clinically relevant and important measures like repeat revascularization.” Today’s interventionalists are fortunate to have several DES options that have been fine-tuned so much so that most of them available in the US marketplace are similarly efficacious. Because of this, the decision to choose one stent over another might not be as informed by comparative differences in efficacy as in the past, Kandzari says. “With today’s DES—almost independent of the brand of stent or the type of antiproliferative drugs—the 1-year rate of repeat revascularization is less than 5%. That’s a dramatic difference than what we even had 10 years ago, and certainly before 20 years ago.” Now, the perhaps more pertinent challenge lies in identifying the slight differences in outcomes among contemporary DES.
2. Consider safety
While eliminating the occurrence of stent thrombosis altogether remains an objective, today’s DES designs have rendered the event rate so low that physicians are more assured in using DES to treat patients previously considered at higher risk, Kandzari says. Comparative data now challenge the role of BMS, and this ambiguity is reflected in clinical practice worldwide. For example, the DAPT Study highlighted that compared with BMS, the risk of long-term stent thrombosis “if anything was lower with DES than it was with BMS,” he explains. While safety should always be a consideration, especially since stent thrombosis can cause MI and even death, deliberate changes in stents have given cardiologists more confidence in their decision making.
3. Deliberate deliverability
Physicians when surveyed have said that stent deliverability and performance rank as highly as safety and efficacy when considering different options, Kandzari reports. While deliverability is relevant, he observes, it is more important to keep in mind that though a procedure may be more convenient with a particular device compared with another, “it’s not really in context with next 15 years or more for the life of the patient.” So if a stent is simple to implant and works best for the patient, great. But if the patient would benefit more from a device that’s a little trickier to implant, up your skill and face the challenge. Attention to technique will be ever more important with forthcoming adoption of bioresorbable scaffolds in clinical practice, he says.
4. Examine DAPT adherence
The BMS versus DES debate is not as heated as it once was, but considering how well a patient will adhere to dual antiplatelet therapy (DAPT) and for how long might sway your decision in a certain direction, Kandzari says. That said, recently revised guidelines now endorse DAPT durations of less than 1 year in selected patients treated with newer generation DES. Still, if “patients have a high risk of bleeding [or] their compliance is challenged with long-term dual antiplatelet therapy,” BMS have historically been considered the better option, he says. But recent trials like ZEUS and LEADERS FREE have challenged this notion, suggesting that even with abbreviated DAPT durations, contemporary DES have similar rates of stent thrombosis and superior rates of reducing restenosis compared with BMS. “Altogether, there seems to be less and less of a role for the use of BMS in clinical practice,” Kandzari says. In addition, observational data also indicate a lower risk of adverse events following noncardiac surgery in patients treated with DES compared with BMS. How much longer will any debate over the two stent types even be relevant? In a recent JACC: Cardiovascular Interventions editorial he discusses the “unspoken reality that an ‘optimal’ DAPT duration does not exist for all patients.” Until more definitive randomized studies can give more clear-cut answers on this issue, BMS may retain some market share, but their window of utility “is increasingly becoming less narrowed,” he says.
5. Geometry matters
In terms of performance, the main differentiating factor among the newest-generation DES choices is geometry, Kandzari reports. How much do they expand? How are the strut cells designed? What are their radial strength and scaffolding properties? If their struts are particularly thin, what are the odds of stent distortion? Because so much comparative research has been done on stents, he recommends studying up on past experience and knowing the geometrical structures of the devices you use inside and out. For example, in a very calcified lesion, would you be able to choose a stent with good radial strength to serve as scaffolding support for the artery itself? Kandzari also recommends thinking about stent geometry with respect to visibility. “The thinner the struts we go, the harder it is to see the stent,” he says, adding that manufacturers are now creatively embedding metals like iridium, molybdenum, or platinum within the devices to increase their radio-opacity.
6. Size appropriately
Many of the early IVUS studies highlighted that, despite the angiographic appearance of the vessel, interventionalists often practice a concept called geographic miss, Kandzari said. “This is where we’re stenting the vessel, but we’re actually leaving residual disease in many segments not adequately covered by the stent,” he explains. So in considering stent selection, it is important to know which device will appropriately cover the entire diseased segment of the vessel, if possible. Considering the diameter of the vessel is essential as well, Kandzari adds, as “the greatest predictor of restenosis with current-generation DES is undersizing of the stent in the vessel itself. Appropriate expansion of the stent and sizing of the stent and achieving the largest permissible minimal luminal area of the stent are important factors in achieving the best outcomes for the patient.”
7. Know your polymers
By definition, DES elute drugs—and you should understand each of their characteristics as well as the polymers releasing them. Specifically, Kandzari recommends knowing drug elution kinetics, safety and efficacy profiles, and how these details influence outcomes like late lumen loss, restenosis rates, and clinical events. Most current DES designs feature durable, or biopermanent, polymers that become a lasting fixture of the stent itself, he explains. Although new bioresorbable-polymer stents are approved for use in the United States, and other designs are in ongoing studies, whether they will “confer [an] additional safety or biocompatibility advantage is something that remains under investigation,” Kandzari says.
8. Adapt for specific lesion subsets
When treating complex lesions, Kandzari suggests thinking about which stent is best for specific lesion types like bifurcation lesions, chronic total occlusions, long lesions, and calcified lesions. “Because we’ve almost leveled the playing field with current DES, it is difficult to say that a particular stent brand is definitely suited for certain indications over others,” he says. “But on the other hand, it also doesn’t mean we should assume a ‘class effect’ of all DES. There are certain settings in which specific stent types have been more extensively studied and therefore may be preferred.” For example, there have been many more dedicated trials with everolimus-eluting stents in unprotected left main disease, chronic total occlusions, and in-stent restenosis, circumstances in which their efficacy may be preferred. So while we may not have a definitive answer on which stent to use for every situation, pay attention to the totality of evidence.
9. Develop cost sensitivity
The fact that different DES brands are now more similar than before in terms of safety and efficacy “has motivated many different hospital programs to largely determine their inventory of stents based on cost alone,” Kandzari explains. Although there are many other reasons for why an interventionalist might choose one stent over another, fellows need to “develop a sensitivity for costs related to the DES.” Cost depends on a hospital’s purchasing volume and also the cost per stent, he says. “Even with a difference of $100 per stent between two stent brands, if you’re doing several thousand procedures a year and you’re using an average of let’s say 1.5 to 1.7 stents per patient, you can imagine that over an annualized basis that $100 difference . . . actually translates into several hundred thousand dollars.”
10. Be ready to explain your choice
Because of the way training programs are designed, fellows often learn to mimic the choices of their mentors, especially with regard to stent selection, Kandzari observes. The presence of manufacturers’ representatives in the cath lab can also add pressure. But regardless of the ultimate reason for your choice, acknowledge the dynamics that influence stent selection and question yourself with every case you perform, he says. Challenging ourselves and encouraging these discussions as operators and colleagues “is actually a positive experience that keeps us grounded in the need for science . . . and why we practice the way we do.” It’s also important to constructively question your coworkers, even if they are more senior than you, Kandzari adds, so that everyone holds each other accountable. “When fellows or patients challenge me, . . . it then makes me provide a good justification for why I recommend a certain medicine to a patient or why I did choose a specific stent. It then motivates me to always keep learning, to have detailed knowledge of the medicines and devices we use to treat patients, and [to know] why we have a particular reason for choosing the therapies we do,” he says.
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